SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Mörgelin M) "

Sökning: WFRF:(Mörgelin M)

  • Resultat 1-50 av 56
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • van Os, G M A, et al. (författare)
  • Induction of Auto-Antibodies Against β(2) -Glycoprotein I in Mice by Protein H of Streptococcus Pyogenes.
  • 2011
  • Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 9:12, s. 2447-2456
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The antiphospholipid syndrome (APS) is characterized by the persistent presence of auto-antibodies against β(2) -Glycoprotein I (β(2) -GPI). β(2) -GPI can exist in two conformations. In plasma it is a circular protein, whereas it adopts a fish-hook shape after binding to phospholipids. Only the latter conformation is recognized by patient antibodies. β(2) -GPI has been shown to interact with Streptococcus pyogenes. Objective: Here we evaluated the potential of S. pyogenes derived proteins to induce auto-antibodies against β(2) -GPI. Methods and results: Four S. pyogenes surface proteins (M1 protein, protein H, SclA and SclB) were found to interact with β(2) -GPI. Only binding to protein H induces a conformational change in β(2) -GPI, thereby exposing a cryptic epitope for APS-related auto-antibodies. Mice were injected with the four proteins. Only mice injected with protein H developed antibodies against the patient antibody related epitope in domain I of β(2) -GPI. Patients with pharyngotonsillitis caused by S. pyogenes who developed antibodies towards protein H also generated anti-β(2) -GPI antibodies. Conclusion: Our study demonstrated that a bacterial protein can induce a conformational change in β(2) -GPI resulting in the formation of auto-antibodies against β(2) -GPI. This constitutes a novel mechanism for the formation of auto-antibodies against β(2) -GPI.
  •  
2.
  • Agar, Cetin, et al. (författare)
  • beta(2)-Glycoprotein I can exist in 2 conformations: implications for our understanding of the antiphospholipid syndrome
  • 2010
  • Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 116:8, s. 1336-1343
  • Tidskriftsartikel (refereegranskat)abstract
    • The antiphospholipid syndrome is defined by the presence of antiphospholipid antibodies in blood of patients with thrombosis or fetal loss. There is ample evidence that beta(2)-glycoprotein I (beta(2)GPI) is the major antigen for antiphospholipid antibodies. The autoantibodies recognize beta(2)GPI when bound to anionic surfaces and not in solution. We showed that beta(2)GPI can exist in at least 2 different conformations: a circular plasma conformation and an "activated" open conformation. We also showed that the closed, circular conformation is maintained by interaction between the first and fifth domain of beta(2)GPI. By changing pH and salt concentration, we were able to convert the conformation of beta(2)GPI from the closed to the open conformation and back. In the activated open conformation, a cryptic epitope in the first domain becomes exposed that enables patient antibodies to bind and form an antibody-beta(2)GPI complex. We also demonstrate that the open conformation of beta(2)GPI prolonged the activated partial thromboplastin time when added to normal plasma, whereas the activated partial thromboplastin time is further prolonged by addition of anti-beta(2)GPI antibodies. The conformational change of beta(2)GPI, and the influence of the autoantibodies may have important consequences for our understanding of the antiphospholipid syndrome. (Blood. 2010; 116(8): 1336-1343)
  •  
3.
  • Agar, Cetin, et al. (författare)
  • beta(2)-Glycoprotein I: a novel component of innate immunity
  • 2011
  • Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 117:25, s. 6939-6947
  • Tidskriftsartikel (refereegranskat)abstract
    • Sepsis is a systemic host response to invasive infection by bacteria. Despite treatment with antibiotics, current mortality rates are in the range of 20%-25%, which makes sepsis the most important cause of death in intensive care. Gram-negative bacteria are a prominent cause of sepsis. Lipopolysaccharide (LPS), one of the major constituents of the outer membrane of Gram-negative bacteria, plays a major role in activating the host's immune response by binding to monocytes and other cells. Several proteins are involved in neutralization and clearance of LPS from the bloodstream. Here, we provide evidence that beta(2)-glycoprotein I (beta(2)GPI) is a scavenger of LPS. In vitro, beta(2)GPI inhibited LPS-induced expression of tissue factor and IL-6 from monocytes and endothelial cells. Binding of beta(2)GPI to LPS caused a conformational change in beta(2)GPI that led to binding of the beta(2)GPI-LPS complex to monocytes and ultimately clearance of this complex. Furthermore, plasma levels of beta(2)GPI were inversely correlated with temperature rise and the response of inflammatory markers after a bolus injection of LPS in healthy individuals. Together, these observations provide evidence that beta(2)GPI is involved in the neutralization and clearance of LPS and identify beta(2)GPI as a component of innate immunity. (Blood. 2011;117(25):6939-6947)
  •  
4.
  • Baker, Naomi L., et al. (författare)
  • Molecular consequences of dominant Bethlem myopathy collagen VI mutations
  • 2007
  • Ingår i: Annals of Neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 62:4, s. 390-405
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Dominant mutations in the three collagen VI genes cause Bethlem myopathy, a disorder characterized by proximal muscle weakness and commonly contractures of the fingers, wrists, and ankles. Although more than 20 different dominant mutations have been identified in Bethlem myopathy patients, the biosynthetic consequences of only a subset of these have been studied, and in many cases, the pathogenic mechanisms remain unknown. Methods: We have screened fourteen Bethlem myopathy patients for collagen VI mutations and performed detailed analyses of collagen VI biosynthesis and intracellular and extracellular assembly. Results: Collagen VI abnormalities were identified in eight patients. One patient produced around half the normal amount of alpha 1(VI) messenger RNA and reduced amounts of collagen VI protein. Two patients had a previously reported mutation causing skipping of COL6A1 exon 14, and three patients had novel mutations leading to in-frame deletions toward the N-terminal end of the triple-helical domain. These mutations have different and complex effects on collagen VI intracellular and extracellular assembly. Two patients had single amino acid substitutions in the A-domains of COL6A2 and COL6A3. Collagen VI intracellular and extracellular assembly was normal in one of these patients. Interpretation: The key to dissecting the pathogenic mechanisms of collagen VI mutations lies in detailed analysis of collagen VI biosynthesis and assembly. The majority of mutations result in secretion and deposition of structurally abnormal collagen VI. However, one A-domain mutation had no detectable effect on assembly, suggesting that it acts by compromising collagen VI interactions in the extracellular matrix of muscle.
  •  
5.
  • Blom, A M, et al. (författare)
  • Structural characterization of inter-alpha-inhibitor. Evidence for an extended shape
  • 1999
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 274:1, s. 298-304
  • Tidskriftsartikel (refereegranskat)abstract
    • Inter-alpha-inhibitor (IalphaI) is a 180-kDa serum protein consisting of three polypeptides. Two of these, the heavy chains 1 and 2 (H1 and H2), are of 75-80 kDa and have similar amino acid sequences. The third polypeptide, bikunin, has a molecular mass of 25 kDa and contains a 7-kDa chondroitin sulfate chain that is covalently linked to the C-terminal amino acid residues of H1 and H2. IalphaI has been shown to be required for the formation of the hyaluronan-containing extracellular matrix of certain cell types. How IalphaI exerts this function is not known, but it appears that upon interaction with cells, the heavy chains are released and become covalently linked to hyaluronan. Our results indicate that IalphaI and its heavy chains are extended molecules; thus, upon electron microscopy, IalphaI appeared to consist of two globular domains connected by a thin structure 31-nm long and the isolated heavy chains of a globular domain and a "tail" about 15-nm long. Analysis of the heavy chains by partial proteolysis showed that the C-terminal halves are particularly sensitive to hydrolysis indicating that they are loosely folded. Furthermore, electron microscopy showed that partially degraded heavy chains lacked the extended regions. Taken together, these results suggest that the N-terminal half of the heavy chains forms a globular domain, whereas the other half has an extended and loosely folded structure.
  •  
6.
  • Edström, Anneli M L, et al. (författare)
  • The major bactericidal activity of human seminal plasma is zinc-dependent and derived from fragmentation of the semenogelins.
  • 2008
  • Ingår i: Journal of immunology. - 1550-6606. ; 181:5, s. 3413-3421
  • Tidskriftsartikel (refereegranskat)abstract
    • One of the major roles of seminal plasma is to provide antimicrobial protection for the spermatozoa in the female reproductive tract. We found that the bactericidal activity of seminal plasma was highest after resolution of the seminal clot and that this antibacterial activity subsequently became greatly diminished. The antibacterial activity was derived from peptides generated by fragmentation of the semenogelins while the semenogelin holoproteins displayed no antibacterial activity. After ejaculation the semenogelin-derived peptides were fragmented to smaller and smaller fragments over time and thereby lost antibacterial activity. This paralleled the loss of antibacterial activity of whole seminal plasma both in vitro and after sexual intercourse. Moreover, the antibacterial activity of the semenogelin-derived peptides generated in seminal plasma was strictly zinc-dependent both at neutral and low pH. These data provide novel roles for the resolution of seminal clots and for the high zinc concentration in human seminal plasma.
  •  
7.
  • Elezagic, D., et al. (författare)
  • Antimicrobial peptides derived from the cartilage.-specific C-type Lectin Domain Family 3 Member A (CLEC3A) – potential in the prevention and treatment of septic arthritis
  • 2019
  • Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584.
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To investigate the antimicrobial activity of peptides derived from C-type Lectin Domain Family 3 Member A (CLEC3A), shed light on the mechanism of antimicrobial activity and assess their potential application in prevention and treatment of septic arthritis. Design: We performed immunoblot to detect CLEC3A peptides in human cartilage extracts. To investigate their antimicrobial activity, we designed peptides and recombinantly expressed CLEC3A domains and used them to perform viable count assays using E.coli, P.aeruginosa and S.aureus. We investigated the mechanism of their antimicrobial activity by fluorescence and scanning electron microscopy, performed ELISA-style immunoassays and transmission electron microscopy to test for lipopolysaccharide binding and surface plasmon resonance to test for lipoteichoic acid (LTA) binding. We coated CLEC3A peptides on titanium, a commonly used prosthetic material, and performed fluorescence microscopy to quantify bacterial adhesion. Moreover, we assessed the peptides’ cytotoxicity against primary human chondrocytes using MTT cell viability assays. Results: CLEC3A fragments were detected in human cartilage extracts. Moreover, bacterial supernatants lead to fragmentation of recombinant and cartilage-derived CLEC3A. CLEC3A-derived peptides killed E.coli, P.aeruginosa and S.aureus, permeabilized bacterial membranes and bound lipopolysaccharide and LTA. Coating CLEC3A antimicrobial peptides (AMPs) on titanium lead to significantly reduced bacterial adhesion to the material. In addition, microbicidal concentrations of CLEC3A peptides in vitro displayed no direct cytotoxicity against primary human chondrocytes. Conclusions: We identify cartilage-specific AMPs originating from CLEC3A, resolve the mechanism of their antimicrobial activity and point to a novel approach in the prevention and treatment of septic arthritis using potent, non-toxic, AMPs.
  •  
8.
  • Eriksson, S., et al. (författare)
  • Antibacterial and antibiofilm effects of sodium hypochlorite against Staphylococcus aureus isolates derived from patients with atopic dermatitis
  • 2017
  • Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963. ; 117:2, s. 513-521
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Atopic dermatitis (AD) is characterized by an increased susceptibility to skin infections. Staphylococcus aureus is reported to dominate in AD lesions and reports have revealed the presence of staphylococcal biofilms. These infections contribute to aggravation of the eczema. Sodium hypochlorite is known to reduce bacterial load of skin lesions, as well as disease severity, in patients with AD, but the effect on biofilms is unknown. Objectives: To investigate the antimicrobial and antibiofilm effects of sodium hypochlorite against S. aureus isolates derived from patients with AD. Methods: Skin biopsies derived from patients with infected AD were examined by scanning electron microscopy (SEM). Using radial diffusion assays, biofilm assays and confocal laser scanning microscopy, we assessed the effect of sodium hypochlorite on S. aureus isolates derived from lesional skin of patients with AD. Results: SEM revealed clusters of coccoid bacteria embedded in fibrin and extracellular substances at the skin of a patient with infected AD. At concentrations of 0·01-0·08%, sodium hypochlorite showed antibacterial effects against planktonic cells. Eradication of S. aureus biofilms in vitro was observed in concentrations ranging from 0·01% to 0·16%. Confocal laser scanning microscopy confirmed these results. Finally, when human AD skin was subjected to sodium hypochlorite in an ex vivo model, a dose of 0·04% reduced the bacteria derived from AD skin. Conclusions: Sodium hypochlorite has antimicrobial and antibiofilm effects against clinical S. aureus isolates. Our findings suggest usage of a higher concentration than currently used in bleach baths of patients with skin-infected AD.
  •  
9.
  • Grommes, Jochen, et al. (författare)
  • Disruption of Platelet-derived Chemokine Heteromers Prevents Neutrophil Extravasation in Acute Lung Injury
  • 2012
  • Ingår i: American Journal of Respiratory and Critical Care Medicine. - 1535-4970. ; 185:6, s. 628-636
  • Tidskriftsartikel (refereegranskat)abstract
    • Rationale: Acute lung injury (ALI) causes high mortality, but its molecular mechanisms and therapeutic options remain ill-defined. Gram-negative bacterial infections are the main cause of ALI, leading to lung neutrophil infiltration, permeability increases, deterioration of gas exchange, and lung damage. Platelets are activated during ALI, but insights into their mechanistic contribution to neutrophil accumulation in the lung are elusive. Objectives: To determine mechanisms of platelet-mediated neutrophil recruitment in ALI. Methods: Interference with platelet-neutrophil interactions using antagonists to P-selectin and glycoprotein IIb/IIIa or a small peptide antagonist disrupting platelet chemokine heteromer formation in mouse models of ALI. Measurements and Main Results: In a murine model of LPS-induced ALI, we uncover important roles for neutrophils and platelets in permeability changes and subsequent lung damage. Furthermore, platelet depletion abrogated lung neutrophil infiltration, suggesting a sequential participation of platelets and neutrophils. Whereas antagonists to P-selectin and glycoprotein IIb/IIIa had no effects on LPS-mediated ALI, antibodies to the platelet-derived chemokines CCL5 and CXCL4 strongly diminished neutrophil eflux and permeability changes. The two chemokines were found to form heteromers in human and murine ALI samples, positively correlating with leukocyte influx into the lung. Disruption of CCL5-CXCL4 heteromers in LPS-, acid-, and sepsis-induced ALI abolished lung edema, neutrophil infiltration, and tissue damage, thereby revealing a causal contribution. Conclusions: Taken together, our data identify a novel function of platelet-derived chemokine heteromers during ALI and demonstrate means for therapeutic interference.
  •  
10.
  • Malmström, Erik, et al. (författare)
  • Targeted mass spectrometry analysis of neutrophil-derived proteins released during sepsis progression.
  • 2014
  • Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 112:6, s. 1230-1243
  • Tidskriftsartikel (refereegranskat)abstract
    • Early diagnosis of severe infectious diseases is essential for timely implementation of lifesaving therapies. In a search for novel biomarkers in sepsis diagnosis we focused on polymorphonuclear neutrophils (PMNs). Notably, PMNs have their protein cargo readily stored in granules and following systemic stimulation an immediate increase of neutrophil-borne proteins can be observed into the circulation of sepsis patients. We applied a combination of mass spectrometry (MS) based approaches, LC-MS/MS and selected reaction monitoring (SRM), to characterise and quantify the neutrophil proteome in healthy or disease conditions. With this approach we identified a neutrophil-derived protein abundance pattern in blood plasma consisting of 20 proteins that can be used as a protein signature for severe infectious diseases. Our results also show that SRM is highly sensitive, specific, and reproducible and, thus, a promising technology to study a complex, dynamic and multifactorial disease such as sepsis.
  •  
11.
  • Mazzucato, M, et al. (författare)
  • Vascular PG-M/versican variants promote platelet adhesion at low shear rates and cooperate with collagens to induce aggregation
  • 2002
  • Ingår i: FASEB Journal. - 1530-6860. ; 16:14, s. 1903-1916
  • Tidskriftsartikel (refereegranskat)abstract
    • We have identified a novel von Willebrand factor/fibrinogen/selectin-independent, platelet adhesion-promoting function of vascular PG-M/versicans that may be relevant in normal venous thrombosis and critical in atherosclerotic conditions. A purification scheme was devised to obtain vascular versicans, which by biochemical, immunochemical, and ultrastructural means were asserted to be 1) composed primarily of isoforms V1 and V2; 2) free of contaminants; 3) prevalently substituted with chondroitin-4-sulfate and dermatan sulfate (DS) chains; and 4) capable of binding hyaluronan to form link protein-stabilized ternary complexes. Real-time analysis of human platelet perfused under diverse shear forces showed that they largely failed to bind to several vascular and nonvascular proteoglycans (PGs). In contrast, they bound in a dose- and shear rate-dependent manner to vascular versicans, exhibiting a unique attachment-detachment kinetics and establishing a firm substrate tethering characterized with no significant aggregation. Digestion of these PGs with lyases and competition experiments with purified glycosaminoglycans revealed that platelet adhesion to vascular versicans was primarily mediated by their DS chains. Incorporation of the versicans into fibrillar collagen substrates augmented their adhesive activity and strongly promoted platelet aggregation at low and high shear rates. Affinity chromatography of platelet surfaces on DS columns identified a 120-140 kDa polypeptide complex that behaved as a specific vascular versican binding membrane ligand in solid-phase binding assays. These findings indicate that selective versican variants of the subendothelium may serve as ancillary GPIbalpha/integrin/selectin-independent platelet ligands in healthy and diseased vascular beds and may be directly responsible for the platelet accruing after rupture of atherosclerotic plaques., versican variants promote platelet adhesion at low shear rates and cooperate with collagens to induce aggregation.
  •  
12.
  • Neumann, Ariane, et al. (författare)
  • Novel Role of the Antimicrobial Peptide LL-37 in the Protection of Neutrophil Extracellular Traps against Degradation by Bacterial Nucleases
  • 2014
  • Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 6:6, s. 860-868
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutrophil extracellular traps (NETs) have been described as a fundamental innate immune defence mechanism. They consist of a nuclear DNA backbone associated with different antimicrobial peptides (AMPs) which are able to engulf and kill pathogens. The AMP LL-37, a member of the cathelicidin family, is highly present in NETs. However, the function of LL-37 within NETs is still unknown because it loses its antimicrobial activity when bound to DNA in the NETs. Using immunofluorescence microscopy, we demonstrate that NETs treated with LL-37 are distinctly more resistant to S. aureus nuclease degradation than nontreated NETs. Biochemical assays utilising a random LL-37-fragment library indicated that the blocking effect of LL-37 on nuclease activity is based on the cationic character of the AMP, which facilitates the binding to neutrophil DNA, thus protecting it from degradation by the nuclease. In good correlation to these data, the cationic AMPs human beta defensin-3 and human neutrophil peptide-1 showed similar protection of neutrophil-derived DNA against nuclease degradation. In conclusion, this study demonstrates a novel role of AMPs in host immune defence: beside its direct antimicrobial activity against various pathogens, cationic AMPs can stabilise neutrophil-derived DNA or NETs against bacterial nuclease degradation. (C) 2014 S. Karger AG, Basel
  •  
13.
  • Nilsson, Maria, et al. (författare)
  • The antibacterial activity of peptides derived from human beta-2 glycoprotein I is inhibited by protein H and M1 protein from Streptococcus pyogenes.
  • 2008
  • Ingår i: Molecular Microbiology. - : Wiley. - 1365-2958 .- 0950-382X. ; 67:3, s. 482-492
  • Tidskriftsartikel (refereegranskat)abstract
    • During the last years, the importance of antibacterial peptides has attracted considerable attention. We report here that peptides derived from the fifth domain of beta-2 glycoprotein I (beta(2)GPI), a human heparin binding plasma protein, have antibacterial activities against Gram-positive and Gram-negative bacteria. Streptococcus pyogenes, an important human pathogen that can survive and grow in human blood, has developed mechanisms to escape the attack by these peptides. Thus, protein H and M1 protein, two surface proteins of the highly pathogenic S. pyogenes AP1 strain, bind full-length beta(2)GPI and thereby prevent the processing of beta(2)GPI by proteases from polymorphonuclear neutrophils (PMNs) into antibacterial peptides. In addition, protein H and M1 protein, released from the bacterial cell wall by PMN-derived proteases, bind to, and inhibit the activity of, beta(2)GPI-derived antibacterial peptides. Taken together, the data suggest that the interaction between the streptococcal proteins and beta(2)GPI or beta(2)GPI-derived peptides presents a novel mechanism to resist an antibacterial attack by beta(2)GPI-cleavage products.
  •  
14.
  •  
15.
  • Smolag, Karolina I., et al. (författare)
  • Complement inhibitor factor H expressed by breast cancer cells differentiates CD14+ human monocytes into immunosuppressive macrophages
  • 2020
  • Ingår i: OncoImmunology. - 2162-4011. ; 9:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Macrophages are a major immune cell type in the tumor microenvironment, where they display a tumor-supporting phenotype. Factor H (FH) is a complement inhibitor that also plays a role in several cellular functions. To date, the phenotype of monocytes stimulated with FH has been unexplored. We discovered that FH is a survival factor for CD14+ primary human monocytes, promoting their differentiation into macrophages in serum-free medium. This activity was localized to the C-terminal domains of FH and it was inhibited in plasma, indicating that the phenomenon may be most relevant in tissues. FH-induced macrophages display characteristics of immunosuppressive cells including expression of CD163 and CD206, release of the anti-inflammatory cytokine IL-10 and changes in metabolism. Furthermore, FH-induced macrophages express low levels of HLA-DR but high levels of co-inhibitory molecule programmed death-ligand 1 (PD-L1), and accordingly, a reduced capacity for T-cell activation. Finally, we show that FH is expressed by human breast cancer cells and that this correlates with the presence of immunosuppressive macrophages, breast cancer recurrence and severity of the disease. We propose that the expression of FH by tumor cells and the promotion of an immunosuppressive cancer microenvironment by this protein should be taken into account when considering the effectiveness of immunotherapies against breast cancer.
  •  
16.
  • Abdillahi, Suado M., et al. (författare)
  • Collagen VI Contains Multiple Host Defense Peptides with Potent In Vivo Activity
  • 2018
  • Ingår i: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 201:3, s. 1007-1020
  • Tidskriftsartikel (refereegranskat)abstract
    • Collagen VI is a ubiquitous extracellular matrix component that forms extensive microfibrillar networks in most connective tissues. In this study, we describe for the first time, to our knowledge, that the collagen VI von Willebrand factor type A like domains exhibit a broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria in human skin infections in vivo. In silico sequence and structural analysis of VWA domains revealed that they contain cationic and amphipathic peptide sequence motifs, which might explain the antimicrobial nature of collagen VI. In vitro and in vivo studies show that these peptides exhibited significant antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa through membrane disruption. Our findings shed new light on the role of collagen VI derived peptides in innate host defense and provide templates for development of peptide-based antibacterial therapies.
  •  
17.
  • Abdillahi, Suado M, et al. (författare)
  • The Pulmonary Extracellular Matrix Is a Bactericidal Barrier Against Haemophilus influenzae in Chronic Obstructive Pulmonary Disease (COPD) : Implications for an in vivo Innate Host Defense Function of Collagen VI
  • 2018
  • Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • Non-typeable Haemophilus influenzae (NTHi) is a Gram-negative human commensal commonly residing in the nasopharynx of preschool children. It occasionally causes upper respiratory tract infection such as acute otitis media, but can also spread to the lower respiratory tract causing bronchitis and pneumonia. There is increasing recognition that NTHi has an important role in chronic lower respiratory tract inflammation, particularly in persistent infection in patients suffering from chronic obstructive pulmonary disease (COPD). Here, we set out to assess the innate protective effects of collagen VI, a ubiquitous extracellular matrix component, against NTHi infection in vivo. In vitro, collagen VI rapidly kills bacteria through pore formation and membrane rupture, followed by exudation of intracellular content. This effect is mediated by specific binding of the von Willebrand A (VWA) domains of collagen VI to the NTHi surface adhesins protein E (PE) and Haemophilus autotransporter protein (Hap). Similar observations were made in vivo specimens from murine airways and COPD patient biopsies. NTHi bacteria adhered to collagen fibrils in the airway mucosa and were rapidly killed by membrane destabilization. The significance in host-pathogen interplay of one of these molecules, PE, was highlighted by the observation that it confers partial protection from bacterial killing. Bacteria lacking PE were more prone to antimicrobial activity than NTHi expressing PE. Altogether the data shed new light on the carefully orchestrated molecular events of the host-pathogen interplay in COPD and emphasize the importance of the extracellular matrix as a novel branch of innate host defense.
  •  
18.
  • Abraham, Elena T., et al. (författare)
  • Collagen's primary structure determines collagen:HSP47 complex stoichiometry
  • 2021
  • Ingår i: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258. ; 297:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Collagens play important roles in development and homeostasis in most higher organisms. In order to function, collagens require the specific chaperone HSP47 for proper folding and secretion. HSP47 is known to bind to the collagen triple helix, but the exact positions and numbers of binding sites are not clear. Here, we employed a collagen II peptide library to characterize high-affinity binding sites for HSP47. We show that many previously predicted binding sites have very low affinities due to the presence of a negatively charged amino acid in the binding motif. In contrast, large hydrophobic amino acids such as phenylalanine at certain positions in the collagen sequence increase binding strength. For further characterization, we determined two crystal structures of HSP47 bound to peptides containing phenylalanine or leucine. These structures deviate significantly from previously published ones in which different collagen sequences were used. They reveal local conformational rearrangements of HSP47 at the binding site to accommodate the large hydrophobic side chain from the middle strand of the collagen triple helix and, most surprisingly, possess an altered binding stoichiometry in the form of a 1:1 complex. This altered stoichiometry is explained by steric collisions with the second HSP47 molecule present in all structures determined thus far caused by the newly introduced large hydrophobic residue placed on the trailing strand. This exemplifies the importance of considering all three sites of homotrimeric collagen as independent interaction surfaces and may provide insight into the formation of higher oligomeric complexes at promiscuous collagen-binding sites.
  •  
19.
  • Bengtson, Sara, et al. (författare)
  • Activation of TAFI on the Surface of Streptococcus pyogenes Evokes Inflammatory Reactions by Modulating the Kallikrein/Kinin System
  • 2009
  • Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 1:1, s. 18-28
  • Tidskriftsartikel (refereegranskat)abstract
    • Bacteria-controlled regulation of host responses to infection is an important virulence mechanism that has been demonstrated to contribute to disease progression. Here we report that the human pathogen Streptococcus pyogenes employs the procarboxypeptidase TAR (thrombin-activatablefibrinolysis inhibitor) to modulate the kallikrein/kinin system. To this end, bacteria initiate a chain of events starting with the recruitment and activation of TAFI. This is followed by the assembly and induction of the contact system at the streptococcal surface, eventually triggering the release of bradykinin (BK). BK is then carboxyterminally truncated by activated TAFI, which converts the peptide from a kinin B-2 receptor ligand to a kinin B-1 receptor (B1R) agonist. Finally, we show that streptococcal supernatants indirectly amplify the B1R response as they act on peripheral blood mononuclear cells to secrete inflammatory cytokines that in turn stimulate upregulation of the B1R on human fibroblasts. Taken together our findings implicate a critical and novel role for streptococci-bound TAR, as it processes BK to a B1R agonist at the bacterial surface and thereby may redirect inflammation from a transient to a chronic state. Copyright (C) 2008 S. Karger AG, Basel
  •  
20.
  • Bettoni, Serena, et al. (författare)
  • C4BP-IgM protein as a therapeutic approach to treat Neisseria gonorrhoeae infections
  • 2019
  • Ingår i: JCI Insight. - : American Society for Clinical Investigation (ASCI). - 2379-3708. ; 4:23
  • Tidskriftsartikel (refereegranskat)abstract
    • Gonorrhea is a sexually transmitted infection with 87 million new cases per year globally. Increasing antibiotic resistance has severely limited treatment options. A mechanism that Neisseria gonorrhoeae uses to evade complement attack is binding of the complement inhibitor C4b-binding protein (C4BP). We screened 107 porin B1a (PorB1a) and 83 PorB1b clinical isolates randomly selected from a Swedish strain collection over the last 10 years and noted that 96/107 (89.7%) PorB1a and 16/83 (19.3%) PorB1b bound C4BP; C4BP binding substantially correlated with the ability to evade complement-dependent killing (r = 0.78). We designed 2 chimeric proteins that fused C4BP domains to the backbone of IgG or IgM (C4BP-IgG; C4BP-IgM) with the aim of enhancing complement activation and killing of gonococci. Both proteins bound gonococci (KD C4BP-IgM = 2.4 nM; KD C4BP-IgG 980.7 nM), but only hexameric C4BP-IgM efficiently outcompeted heptameric C4BP from the bacterial surface, resulting in enhanced complement deposition and bacterial killing. Furthermore, C4BP-IgM substantially attenuated the duration and burden of colonization of 2 C4BP-binding gonococcal isolates but not a non-C4BP-binding strain in a mouse vaginal colonization model using human factor H/C4BP-transgenic mice. Our preclinical data present C4BP-IgM as an adjunct to conventional antimicrobials for the treatment of gonorrhea.
  •  
21.
  • Cattaruzza, S, et al. (författare)
  • Distribution of PG-M/versican variants in human tissues and de novo expression of isoform V3 upon endothelial cell activation, migration, and neoangiogenesis in vitro
  • 2002
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 277:49, s. 47626-47635
  • Tidskriftsartikel (refereegranskat)abstract
    • We have carried out a comprehensive molecular mapping of PG-M/versican isoforms V0-V3 in adult human tissues and have specifically investigated how the expression of these isoforms is regulated in endothelial cells in vitro. A survey of 21 representative tissues highlighted a prevalence of V1 mRNA, demonstrated that the relative frequency of expression was V1>V2>V3greater than or equal toV2; and showed that <15% of the tissues transcribed significant levels of all four isoforms. By employing novel and previously described anti-versican antibodies we verified a ubiquitous versican deposition in normal and tumor-associated vascular structures and disclosed differences in the glycanation profiles of versicans produced in different vascular beds. Resting endothelial cells isolated from different tissue sources transcribed several of the versican isoforms but consistently failed to translate these mRNAs into detectable proteoglycans. However, if stimulated with tumor necrosis factor-α or vascular endothelial growth factor, they altered their versican expression by de novo transcribing the V3 isoform and by exhibiting a moderate V1/V2 production. Induced versican synthesis and de novo V3 expression was also observed in endothelial cells elicited to migrate in a wound-healing model in vitro and in angiogenic endothelial cells forming tubule-like structures in Matrigel or fibrin clots. The results suggest that, independent of the degree of vascularization, human adult tissues show a limited expression of versican isoforms V0, V2, and V3 and that endothelial cells may contribute to the deposition of versican in vascular structures, but only following proper stimulation.
  •  
22.
  • Eliasson, Mette, et al. (författare)
  • Streptococcus pneumoniae induces expression of the antibacterial CXC chemokine MIG/CXCL9 via MyD88-dependent signaling in a murine model of airway infection.
  • 2010
  • Ingår i: Microbes and Infection. - : Elsevier BV. - 1769-714X .- 1286-4579. ; 12, s. 565-573
  • Tidskriftsartikel (refereegranskat)abstract
    • MIG/CXCL9 belongs to the CXC family of chemokines and participates in the regulation of leukocyte-trafficking and angiogenesis. Certain chemokines, including human MIG/CXCL9, exert strong antibacterial activity in vitro, although the importance of this property in vivo is unknown. In the present study, we investigated the expression and a possible role for MIG/CXCL9 in host defense during mucosal airway infection caused by Streptococcus pneumoniae in vivo. We found that intranasal challenge of C57BL/6 wild-type mice with pneumococci elicited production of high levels of MIG/CXCL9 in the lungs via the MyD88-dependent signaling pathway. Whereas both human and murine MIG/CXCL9 showed efficient killing of S. pneumoniae in vitro, MIG/CXCL9 knock-out mice were not more susceptible to pneumococcal infection. Our data demonstrate that, in vivo this chemokine probably has a redundant role, acting together with other antibacterial peptides and chemokines, in innate and adaptive host defense mechanisms against pneumococcal infections.
  •  
23.
  • Ermert, David, et al. (författare)
  • Human igg increases virulence of streptococcus pyogenes through complement evasion
  • 2018
  • Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 200:10, s. 3495-3505
  • Tidskriftsartikel (refereegranskat)abstract
    • Streptococcus pyogenes is an exclusively human pathogen that can provoke mild skin and throat infections but can also cause fatal septicemia. This gram-positive bacterium has developed several strategies to evade the human immune system, enabling S. pyogenes to survive in the host. These strategies include recruiting several human plasma proteins, such as the complement inhibitor, C4b-binding protein (C4BP), and human (hu)-IgG through its Fc region to the bacterial surface to evade immune recognition. We identified a novel virulence mechanism whereby IgG-enhanced binding of C4BP to five of 12 tested S. pyogenes strains expressed diverse M proteins that are important surface-expressed virulence factors. Importantly, all strains that bound C4BP in the absence of IgG bound more C4BP when IgG was present. Further studies with an M1 strain that additionally expressed protein H, also a member of the M protein family, revealed that binding of hu-IgG Fc to protein H increased the affinity of protein H for C4BP. Increased C4BP binding accentuated complement downregulation, resulting in diminished bacterial killing. Accordingly, mortality from S. pyogenes infection in hu-C4BP transgenic mice was increased when hu-IgG or its Fc portion alone was administered concomitantly. Electron microscopy analysis of human tissue samples with necrotizing fasciitis confirmed increased C4BP binding to S. pyogenes when IgG was present. Our findings provide evidence of a paradoxical function of hu-IgG bound through Fc to diverse S. pyogenes isolates that increases their virulence and may counteract the beneficial effects of IgG opsonization.
  •  
24.
  • Ermert, David, et al. (författare)
  • The molecular basis of human igg-mediated enhancement of C4b-binding protein recruitment to group a streptococcus
  • 2019
  • Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 10:JUN
  • Tidskriftsartikel (refereegranskat)abstract
    • Streptococcus pyogenes infects over 700 million people worldwide annually. Immune evasion strategies employed by the bacteria include binding of the complement inhibitors, C4b-binding protein (C4BP) and Factor H in a human-specific manner. We recently showed that human IgG increased C4BP binding to the bacterial surface, which promoted streptococcal immune evasion and increased mortality in mice. We sought to identify how IgG promotes C4BP binding to Protein H, a member of the M protein family. Dimerization of Protein H is pivotal for enhanced binding to human C4BP. First, we illustrated that Protein H, IgG, and C4BP formed a tripartite complex. Second, surface plasmon resonance revealed that Protein H binds IgG solely through Fc, but not Fab domains, and with high affinity (IgG-Protein H: KD = 0.4 nM; IgG-Fc-Protein H: KD ≤1.6 nM). Each IgG binds two Protein H molecules, while up to six molecules of Protein H bind one C4BP molecule. Third, interrupting Protein H dimerization either by raising temperature to 41°C or with a synthetic peptide prevented IgG-Protein H interactions. IgG-Fc fragments or monoclonal human IgG permitted maximal C4BP binding when used at concentrations from 0.1 to 10 mg/ml. In contrast, pooled human IgG enhanced C4BP binding at concentrations up to 1 mg/ml; decreased C4BP binding at 10 mg/ml occurred probably because of Fab-streptococcal interactions at these high IgG concentrations. Taken together, our data show how S. pyogenes exploits human IgG to evade complement and enhance its virulence. Elucidation of this mechanism could aid design of new therapeutics against S. pyogenes.
  •  
25.
  • Friedrich, M V, et al. (författare)
  • Structural basis of glycosaminoglycan modification and of heterotypic interactions of perlecan domain V
  • 1999
  • Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 1089-8638 .- 0022-2836. ; 294:1, s. 259-270
  • Tidskriftsartikel (refereegranskat)abstract
    • The C-terminal perlecan domain V of about 90 kDa consists of laminin-type G domain modules (LG) (25 kDa) and epidermal growth factor-like modules (EG) (4 kDa) in the tandem arrangement LG1-EG1-EG2-LG2-EG3-EG4-LG3. Several shorter fragments have been prepared by recombinant production in mammalian cells and used to map the single glycosaminoglycan (GAG) substitution site and the binding of several carbohydrate and protein ligands. This identified a Ser3511 residue located in a short link region between EG4 and LG3 as being involved in GAG attachment. Electron microscopy provided evidence that the same substitution exists in tissue forms of perlecan. Heparan sulphate attached to this site was shown to bind to the alpha1LG4 module of laminin-1, indicating a role in basement membrane assembly and cell-matrix interactions. This site is also close to an Asn-Asp bond which is readily cleaved by an endogenous protease that depends on the presence of Asp and the LG2 module. A weak heparin binding site was shown to include the EG2 module, which contains five basic residues. Binding to sulphatides and the alpha-dystroglycan receptor was much stronger and required at least two LG modules. However, single LG modules appear to be sufficient for the interaction with the laminin-nidogen complex, while EG3-4 and some flanking regions are apparently involved in fibulin-2 binding. These observations indicate that a complex modular structure is required for domain V in order to provide a rich repertoire of potential biological functions.
  •  
26.
  • Gela, Anele, et al. (författare)
  • Eotaxin-3 (CCL26) exerts innate host defense activities that are modulated by mast cell proteases
  • 2015
  • Ingår i: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 70:2, s. 161-170
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundDuring bacterial infections of the airways, a Th1-profiled inflammation promotes the production of several host defense proteins and peptides with antibacterial activities including -defensins, ELR-negative CXC chemokines, and the cathelicidin LL-37. These are downregulated by Th2 cytokines of the allergic response. Instead, the eosinophil-recruiting chemokines eotaxin-1/CCL11, eotaxin-2/CCL24, and eotaxin-3/CCL26 are expressed. This study set out to investigate whether these chemokines could serve as innate host defense molecules during allergic inflammation. MethodsAntibacterial activities of the eotaxins were investigated using viable count assays, electron microscopy, and methods assessing bacterial permeabilization. Fragments generated by mast cell proteases were characterized, and their potential antibacterial, receptor-activating, and lipopolysaccharide-neutralizing activities were investigated. ResultsCCL11, CCL24, and CCL26 all showed potent bactericidal activity, mediated through membrane disruption, against the airway pathogens Streptococcus pneumoniae, Staphylococcus aureus, Nontypeable Haemophilus influenzae, and Pseudomonas aeruginosa. CCL26 retained bactericidal activity in the presence of salt at physiologic concentrations, and the region holding the highest bactericidal activity was the cationic and amphipathic COOH-terminus. Proteolysis of CCL26 by chymase and tryptase, respectively, released distinct fragments of the COOH- and NH2-terminal regions. The COOH-terminal fragment retained antibacterial activity while the NH2-terminal had potent LPS-neutralizing properties in the order of CCL26 full-length protein. An identical fragment to NH2-terminal fragment generated by tryptase was obtained after incubation with supernatants from activated mast cells. None of the fragments activated the CCR3-receptor. ConclusionsTaken together, the findings show that the eotaxins can contribute to host defense against common airway pathogens and that their activities are modulated by mast cell proteases.
  •  
27.
  • Gialeli, Chrysostomi, et al. (författare)
  • Complement inhibitor CSMD1 modulates epidermal growth factor receptor oncogenic signaling and sensitizes breast cancer cells to chemotherapy
  • 2021
  • Ingår i: Journal of Experimental and Clinical Cancer Research. - : Springer Science and Business Media LLC. - 1756-9966. ; 40:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Human CUB and Sushi multiple domains 1 (CSMD1) is a large membrane-bound tumor suppressor in breast cancer. The current study aimed to elucidate the molecular mechanism underlying the effect of CSMD1 in highly invasive triple negative breast cancer (TNBC). Methods: We examined the antitumor action of CSMD1 in three TNBC cell lines overexpressing CSMD1, MDA-MB-231, BT-20 and MDA-MB-486, in vitro using scanning electron microscopy, proteome array, qRT-PCR, immunoblotting, proximity ligation assay, ELISA, co-immunoprecipitation, immunofluorescence, tumorsphere formation assays and flow cytometric analysis. The mRNA expression pattern and clinical relevance of CSMD1 were evaluated in 3520 breast cancers from a modern population-based cohort. Results: CSMD1-expressing cells had distinct morphology, with reduced deposition of extracellular matrix components. We found altered expression of several cancer-related molecules, as well as diminished expression of signaling receptors including Epidermal Growth Factor Receptor (EGFR), in CSMD1-expressing cells compared to control cells. A direct interaction of CSMD1 and EGFR was identified, with the EGF-EGFR induced signaling cascade impeded in the presence of CSMD1. Accordingly, we detected increased ubiquitination levels of EGFR upon activation in CSMD1-expressing cells, as well as increased degradation kinetics and chemosensitivity. Accordingly, CSMD1 expression rendered tumorspheres pretreated with gefitinib more sensitive to chemotherapy. In addition, higher mRNA levels of CSMD1 tend to be associated with better outcome of triple negative breast cancer patients treated with chemotherapy. Conclusions: Our results indicate that CSMD1 cross-talks with the EGFR endosomal trafficking cascade in a way that renders highly invasive breast cancer cells sensitive to chemotherapy. Our study unravels one possible underlying molecular mechanism of CSMD1 tumor suppressor function and may provide novel avenues for design of better treatment.
  •  
28.
  • Kassner, A, et al. (författare)
  • Molecular structure and interaction of recombinant human type XVI collagen
  • 2004
  • Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 1089-8638 .- 0022-2836. ; 339:4, s. 835-853
  • Tidskriftsartikel (refereegranskat)abstract
    • Collagen XVI is a minor component of at least two different extracellular fibrillar networks of specialized regions of skin and cartilage. In skin, collagen XVI is integrated into particular fibrillin-rich microfibrils lacking an amorphous elastin core. In cartilage, collagen XVI is a component of small heterotypic D-banded fibrils, mainly occurring in the territorial matrix of chondrocytes. Here, we present the first direct evidence for the molecular structure and functional properties of these fibril-associated collagens with interrupted triple helices (FACIT). We have expressed recombinantly the full-length alpha1 chain of human collagen XVI in HEK 293 EBNA cells in large quantities using an episomal expression system. Secreted full-length recombinant collagen XVI forms stable disulfide-bonded homotrimers and is rapidly proteolytically processed to distinct fragments at specific protease sequence motifs, one resembling an aggrecanase recognition site. Limited trypsin digestion assays and thermal transition curves imply sequential thermal denaturation of individual triple helical domains of this recombinant collagen, similar to authentic collagen XVI. Molecular images of collagen XVI reveal rod-like molecules which harbor multiple sharp kinks attributing a highly flexible structure presumably introduced by non-collagenous (NC) regions. Terminally located cloverleaf-shaped nodules correspond to the large NC NC11 domain of trimeric collagen XVI. The total length of individual trimeric recombinant collagen XVI molecules constitutes about 240 nm as calculated by atomic force and negative staining electron microscopy. Recombinant collagen XVI interacts with fibrillin-1 and with fibronectin indicating multiple molecular interactions in which this ubiquitously expressed and versatile FACIT-collagen can participate. In vitro generated collagen XVI provides an indispensable tool for future determination of its function during supramolecular assembly of matrix aggregates and its role in maintenance, organization and interaction of fibrillar structures. (C) 2004 Elsevier Ltd. All rights reserved.
  •  
29.
  • Klatt, A R, et al. (författare)
  • Molecular structure and tissue distribution of matrilin-3, a filament-forming extracellular matrix protein expressed during skeletal development
  • 2000
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 275:6, s. 3999-4006
  • Tidskriftsartikel (refereegranskat)abstract
    • Matrilin-3 is a recently identified member of the superfamily of proteins containing von Willebrand factor A-like domains and is able to form hetero-oligomers with matrilin-1 (cartilage matrix protein) via a C-terminal coiled-coil domain. Full-length matrilin-3 and a fragment lacking the assembly domain were expressed in 293-EBNA cells, purified, and subjected to biochemical characterization. Recombinantly expressed full-length matrilin-3 occurs as monomers, dimers, trimers, and tetramers, as detected by electron microscopy and SDS-polyacrylamide gel electrophoresis, whereas matrilin-3, purified from fetal calf cartilage, forms homotetramers as well as hetero-oligomers of variable stoichiometry with matrilin-1. In the matrix formed by cultured chondrosarcoma cells, matrilin-3 is found in a filamentous, collagen-dependent network connecting cells and in a collagen-independent pericellular network. Affinity-purified antibodies detect matrilin-3 expression in a variety of mouse cartilaginous tissues, such as sternum, articular, and epiphyseal cartilage, and in the cartilage anlage of developing bones. It is found both inside the lacunae and in the interterritorial matrix of the resting, proliferating, hypertrophic, and calcified cartilage zones, whereas the expression is lower in the superficial articular cartilage. In trachea and in costal cartilage of adult mice, an expression was seen in the perichondrium. Furthermore, matrilin-3 is found in bone, and its expression is, therefore, not restricted to chondroblasts and chondrocytes.
  •  
30.
  • Köhler, Anna, et al. (författare)
  • New specific HSP47 functions in collagen subfamily chaperoning
  • 2020
  • Ingår i: FASEB Journal. - 0892-6638. ; 34:9, s. 12040-12052
  • Tidskriftsartikel (refereegranskat)abstract
    • Although collagens are the most abundant proteins implicated in various disease pathways, essential mechanisms required for their proper folding and assembly are poorly understood. Heat-shock protein 47 (HSP47), an ER-resident chaperone, was mainly reported to fulfill key functions in folding and secretion of fibrillar collagens by stabilizing pro-collagen triple-helices. In this study, we demonstrate unique functions of HSP47 for different collagen subfamilies. Our results show that HSP47 binds to the N-terminal region of procollagen I and is essential for its secretion. However, HSP47 ablation does not majorly impact collagen VI secretion, but its lateral assembly. Moreover, specific ablation of Hsp47 in murine keratinocytes revealed a new role for the transmembrane collagen XVII triple-helix formation. Incompletely folded collagen XVII C-termini protruding from isolated HSP47 null keratinocyte membrane vesicles could be fully restored upon the application of recombinant HSP47. Thus, our study expands the current view regarding the client repertoire and function of HSP47, as well as emphasizes its importance for transmembrane collagen folding.
  •  
31.
  • Lindblom, Anders, et al. (författare)
  • The intrinsic factor-vitamin B12 receptor, cubilin, is assembled into trimers via a coiled-coil alpha-helix
  • 1999
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 274:10, s. 6374-6380
  • Tidskriftsartikel (refereegranskat)abstract
    • A large protein was purified from bovine kidney, using selective extraction with EDTA to solubilize proteins anchored by divalent cation-dependent interactions. An antiserum raised against the purified protein labeled the apical cell surface of the epithelial cells in proximal tubules and the luminal surface of small intestine. Ten peptide sequences, derived from the protein, all matched the recently published sequences for rat (Moestrup, S. K., Kozyraki, R., Kristiansen, M., Kaysen, J. H., Holm Rasmussen, H., Brault, D., Pontillon, F., Goda, F. O., Christensen, E. I., Hammond, T. G., and Verroust, P. J. (1998) J. Biol. Chem. 273, 5235-5242) and human cubilin, a receptor for intrinsic factor-vitamin B12 complexes, identifying the protein as bovine cubilin. In electron microscopy, a three-armed structure was seen, indicating an oligomerization of three identical subunits. This model was supported by the Mr values of about 1,500,000 for the intact protein and 440,000 for its subunits obtained by analytical ultracentrifugation. In a search for a potential assembly domain, we identified a region of heptad repeats in the N-terminal part of the cubilin sequence. Computer-assisted analysis supported the presence of a coiled-coil alpha-helix between amino acids 103 and 132 of the human cubilin sequence and predicted the formation of a triple coiled-coil. We therefore conclude that cubilin forms a noncovalent trimer of identical subunits connected by an N-terminal coiled-coil alpha-helix.
  •  
32.
  • Linders, Johan, et al. (författare)
  • Complement Component 3 Is Required for Tissue Damage, Neutrophil Infiltration, and Ensuring NET Formation in Acute Pancreatitis
  • 2020
  • Ingår i: European Surgical Research. - : S. Karger AG. - 0014-312X .- 1421-9921. ; 61:6, s. 163-176
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Neutrophil extracellular traps (NETs) are known to play an important role in the pathophysiology of acute pancreatitis (AP). Activation of the complement cascade has been shown to occur in AP. The aim of this study was to examine whether complement component 3 is involved in the generation of NETs in AP.METHODS: AP was induced in wild-type and C3-deficient mice by retrograde infusion of taurocholate into the pancreatic duct. Blood, lung, and pancreas tissue were collected and MPO activity was determined in lung and pancreas tissue. Histological examination of the inflamed pancreas was performed. Plasma levels of CXCL2, MMP-9, IL-6, and DNA-histone complexes as well as pancreatic levels of CXCL1 and CXCL2 were determined by use of enzyme-linked immunosorbent assay. NETs were detected in the pancreas by electron microscopy. The amount of MPO and citrullinated histone 3 in neutrophils isolated from bone marrow was examined using flow cytometry.RESULTS: In C3-deficient mice, challenge with taurocholate yielded much fewer NETs in the pancreatic tissue compared with wild-type controls. Taurocholate-induced blood levels of amylase, tissue injury, and neutrophil recruitment in the pancreas were markedly reduced in the mice lacking C3. Furthermore, MPO levels in the lung, and plasma levels of IL-6, MMP-9, and CXCL2 were significantly lower in the C3-deficient mice compared to wild-type mice after the induction of AP. In vitro studies revealed that neutrophils from C3-deficient mice had normal NET-forming ability and recombinant C3a was not capable of directly inducing NETs formation in the wild-type neutrophils.CONCLUSION: C3 plays an important role in the pathophysiology of AP as it is necessary for the recruitment of neutrophils into the pancreas and ensuring NETs formation. Targeting C3 could hence be a potential strategy to ameliorate local damage as well as remote organ dysfunction in AP.
  •  
33.
  • Linge, Helena M, et al. (författare)
  • The human CXC chemokine granulocyte chemotactic protein 2 (GCP-2)/CXCL6 possesses membrane-disrupting properties and is antibacterial
  • 2008
  • Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596 .- 0066-4804. ; 52:7, s. 2599-2607
  • Tidskriftsartikel (refereegranskat)abstract
    • Granulocyte chemotactic protein 2 (GCP-2)/CXCL6 is a CXC chemokine expressed by macrophages and epithelial and mesenchymal cells during inflammation. Through binding and activation of its receptors (CXCR1 and CXCR2), it exerts neutrophil-activating and angiogenic activities. Here we show that GCP-2/CXCL6 itself is antibacterial. Antibacterial activity against gram-positive and gram-negative pathogenic bacteria of relevance to mucosal infections was seen at submicromolar concentrations (minimal bactericidal concentration at which 50% of strains tested were killed, 0.063 +/- 0.01 to 0.37 +/- 0.03 muM). In killed bacteria, GCP-2/CXCL6 associated with bacterial surfaces, which showed membrane disruption and leakage. A structural prediction indicated the presence of three antiparallel NH(2)-terminal beta-sheets and a short amphipathic COOH-terminal alpha-helix; the latter feature is typical of antimicrobial peptides. However, when the synthetic derivatives corresponding to the NH(2)-terminal (50 amino acids) and COOH-terminal (19 amino acids, corresponding to the putative alpha-helix) regions were compared, higher antibacterial activity was observed for the NH(2)-terminus-derived peptide, indicating that the holopeptide is necessary for full antibacterial activity. An artificial model of bacterial membranes confirmed these findings. The helical content of GCP-2/CXCL6 in the presence or absence of lipopolysaccharide or negatively charged membranes was studied by circular dichroism. As with many antibacterial peptides, membrane disruption by GCP-2/CXCL6 was dose-dependently reduced in the presence of NaCl, which, we here demonstrate, inhibited the binding of the peptide to the bacterial surface. Compared with CXC chemokines ENA-78/CXCL5 and NAP-2/CXCL7, GCP-2/CXCL6 showed a 90-fold-higher antibacterial activity. Taken together, GCP/CXCL6, in addition to its chemotactic and angiogenic properties, is likely to contribute to direct antibacterial activity during localized infection.
  •  
34.
  • M Abdillahi, Suado, et al. (författare)
  • Collagen VI Encodes Antimicrobial Activity: Novel Innate Host Defense Properties of the Extracellular Matrix.
  • 2012
  • Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 4:4, s. 371-376
  • Tidskriftsartikel (refereegranskat)abstract
    • Collagen type VI is a subepithelial extracellular matrix component in airways and an adhesive substrate for oral pathogens [Bober et al.: J Innate Immun 2010;2:160-166]. Here, we report that collagen VI displays a dose-dependent antimicrobial activity against group A, C, and G streptococci by membrane disruption in physiological conditions. The data disclose previously unrecognized aspects of the extracellular matrix in innate host defense.
  •  
35.
  • M Abdillahi, Suado, et al. (författare)
  • Collagen VI Is Upregulated in COPD and Serves Both as an Adhesive Target and a Bactericidal Barrier for Moraxella catarrhalis.
  • 2015
  • Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 7:5, s. 506-517
  • Tidskriftsartikel (refereegranskat)abstract
    • Moraxella catarrhalis is a Gram-negative human mucosal commensal and pathogen. It is a common cause of exacerbation in chronic obstructive pulmonary disease (COPD). During the process of infection, host colonization correlates with recognition of host molecular patterns. Importantly, in COPD patients with compromised epithelial integrity the underlying extracellular matrix is exposed and provides potential adhesive targets. Collagen VI is a ubiquitous fibrillar component in the airway mucosa and has been attributed both adhesive and killing properties against Gram-positive bacteria. However, less is known regarding Gram-negative microorganisms. Therefore, in the present study, the interaction of M. catarrhalis with collagen VI was characterized. We found that collagen VI is upregulated in the airways of COPD patients and exposed upon epithelial desquamation. Ex vivo, we inoculated airway biopsies and fibroblasts from COPD patients with M. catarrhalis. The bacteria specifically adhered to collagen VI-containing matrix fibrils. In vitro, purified collagen VI microfibrils bound to bacterial surface structures. The primary adhesion target was mapped to the collagen VI α2-chain. Upon exposure to collagen VI, bacteria were killed by membrane destabilization in physiological conditions. These previously unknown properties of collagen VI provide novel insights into the extracellular matrix innate immunity by quickly entrapping and killing pathogen intruders. © 2015 S. Karger AG, Basel.
  •  
36.
  • Malmström, Erik, et al. (författare)
  • Protein C inhibitor - a novel antimicrobial agent
  • 2009
  • Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 5:12, s. e1000698-
  • Tidskriftsartikel (refereegranskat)abstract
    • Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which subsequently leads to their permeabilization. As shown by negative staining electron microscopy, treatment of Escherichia coli or Streptococcus pyogenes bacteria with PCI triggers membrane disruption followed by the efflux of bacterial cytosolic contents and bacterial killing. The antimicrobial activity of PCI is located to the heparin-binding site of the protein and a peptide spanning this region was found to mimic the antimicrobial activity of PCI, without causing lysis or membrane destruction of eukaryotic cells. Finally, we show that platelets can assemble PCI on their surface upon activation. As platelets are recruited to the site of a bacterial infection, these results may explain our finding that PCI levels are increased in tissue biopsies from patients suffering from necrotizing fasciitis caused by S. pyogenes. Taken together, our data describe a new function for PCI in innate immunity.
  •  
37.
  • Marx, P. F., et al. (författare)
  • The activation peptide of thrombin-activatable fibrinolysis inhibitor: a role in activity and stability of the enzyme?
  • 2009
  • Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 7:3, s. 445-452
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Thrombin-activatable fibrinolysis inhibitor (TAFI) is a 56-kDa procarboxypeptidase. Proteolytic enzymes activate TAFI into TAFIa, an inhibitor of fibrinolysis, by cleaving off the N-terminal activation peptide (amino acids 1-92), from the enzyme moiety. Activated TAFI is unstable, with a half-life of approximately 10 min at 37 degrees C. So far, it is unknown whether the activation peptide is released or remains attached to the catalytic domain, and whether it influences TAFIa's properties. The current study was performed to clarify these issues. Methods: TAFI was activated, and the activity and half-life of the enzyme were determined in the presence and absence of the activation peptide. Results: TAFIa was active both before and after removal of the activation peptide, and the half-life of TAFIa was identical in the two preparations. Furthermore, we observed that intrinsically inactivated TAFIa (TAFIai) aggregated into large, insoluble complexes that could be removed by centrifugation. Conclusions: The data presented in this article show that the activation peptide of TAFI is not required for TAFIa activity and that the activation peptide has no effect on the stability of the enzyme. These results are in favour of a model in which the activation peptide solely stabilizes the structure of the proenzyme. After activation of TAFI and subsequent breakage of interactions between the activation peptide and the catalytic domain, the activation peptide is no longer capable of performing this stabilizing task, and the integrity of the catalytic domain is lost rapidly. The resulting TAFIai is more prone to proteolysis and aggregation.
  •  
38.
  • Naudin, Clément, et al. (författare)
  • Active but inoperable thrombin is accumulated in a plasma protein layer surrounding Streptococcus pyogenes.
  • 2015
  • Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 114:4, s. 717-726
  • Tidskriftsartikel (refereegranskat)abstract
    • Activation of thrombin is a critical determinant in many physiological and pathological processes including haemostasis and inflammation. Under physiological conditions many of these functions are involved in wound healing or eradication of an invading pathogen. However, when activated systemically, thrombin can contribute to severe and life-threatening conditions by causing complications such as multiple multi-organ failure and disseminated intravascular coagulation. In the present study we investigated how the activity of thrombin is modulated when it is bound to the surface of Streptococcus pyogenes. Our data show that S. pyogenes bacteria become covered with a proteinaceous layer when incubated with human plasma, and that thrombin is a constituent of this layer. Though the coagulation factor is found attached to the bacteria with a functional active site, thrombin has lost its capacity to interact with its natural substrates and inhibitors. Thus, the interaction of bacteria with human plasma renders thrombin completely inoperable at the streptococcal surface. This could represent a host defense mechanism to avoid systemic activation of coagulation which could be otherwise induced when bacteria enter the circulation and cause systemic infection.
  •  
39.
  • Perissinotto, D, et al. (författare)
  • Avian neural crest cell migration is diversely regulated by the two major hyaluronan-binding proteoglycans PG-M/versican and aggrecan
  • 2000
  • Ingår i: Development: For advances in developmental biology and stem cells. - 1477-9129. ; 127:13, s. 2823-2842
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been proposed that hyaluronan-binding proteoglycans play an important role as guiding cues during neural crest (NC) cell migration, but their precise function has not been elucidated. In this study, we examine the distribution, structure and putative role of the two major hyaluronan-binding proteoglycans, PG-M/versicans and aggrecan, during the course of avian NC development. PG-M/versicans V0 and V1 are shown to be the prevalent isoforms at initial and advanced phases of NC cell movement, whereas the V2 and V3 transcripts are first detected following gangliogenesis. During NC cell dispersion, mRNAs for PG-M/versicans V0/V1 are transcribed by tissues lining the NC migratory pathways, as well as by tissues delimiting nonpermissive areas. Immunohistochemistry confirm the deposition of the macromolecules in these regions and highlight regional differences in the density of these proteoglycans. PG-M/versicans assembled within the sclerotome rearrange from an initially uniform distribution to a preferentially caudal localization, both at the mRNA and protein level. This reorganization is a direct consequence of the metameric NC cell migration through the rostral portion of the somites. As suggested by previous in situ hybridizations, aggrecan shows a virtually opposite distribution to PG-M/versicans being confined to the perinotochordal ECM and extending dorsolaterally in a segmentally organized manner eventually to the entire spinal cord at axial levels interspacing the ganglia. PG-M/versicans purified from the NC migratory routes are highly polydispersed, have an apparent M(r) of 1,200-2,000 kDa, are primarily substituted with chondroitin-6-sulfates and, upon chondroitinase ABC digestion, are found to be composed of core proteins with apparent M(r )of 360-530, 000. TEM/rotary shadowing analysis of the isolated PG-M/versicans confirmed that they exhibit the characteristic bi-globular shape, have core proteins with sizes predicted for the V0/V1 isoforms and carry relatively few extended glycosaminoglycan chains. Orthotopical implantation of PG-M/versicans immobilized onto transplantable micromembranes tend to 'attract' moving cells toward them, whereas similar implantations of a notochordal type-aggrecan retain both single and cohorts of moving NC cells in close proximity of the implant and thereby perturb their spatiotemporal migratory pattern. NC cells fail to migrate through three-dimensional collagen type I-aggrecan substrata in vitro, but locomote in a haptotactic manner through collagen type I-PG-M/versican V0 substrata via engagement of HNK-1 antigen-bearing cell surface components. The present data suggest that PG-M/versicans and notochordal aggrecan exert divergent guiding functions during NC cell dispersion, which are mediated by both their core proteins and glycosaminoglycan side chains and may involve 'haptotactic-like' motility phenomena. Whereas aggrecan defines strictly impenetrable embryonic areas, PG-M/versicans are central components of the NC migratory pathways favoring the directed movement of the cells.
  •  
40.
  • Petrlova, Jitka, et al. (författare)
  • The fibrillogenic L178H variant of apolipoprotein A-I forms helical fibrils.
  • 2012
  • Ingår i: Journal of Lipid Research. - 1539-7262. ; 53:3, s. 390-398
  • Tidskriftsartikel (refereegranskat)abstract
    • A number of amyloidogenic variants of apolipoprotein A-I (apoA-I) have been discovered but most have not been analyzed. Previously, we showed that the G26R mutation of apoA-I leads to increased β-strand structure, increased N-terminal protease susceptibility and increased fibril formation after several days of incubation. In vivo, this and other variants mutated in the N-terminal domain (residues 26 to ~90) lead to renal and hepatic accumulation. In contrast, several mutations identified within residues 170 to 178 lead to cardiac, laryngeal, and cutaneous protein deposit. Here, we describe the structural changes in the fibrillogenic variant L178H. Like G26R, the initial structure of the protein exhibits altered tertiary conformation relative to WT protein along with decreased stability and an altered lipid binding profile. However, in contrast to G26R, L178H undergoes an increase in helical structure upon incubation at 37oC with a t1/2 of about 12 days. Upon prolonged incubation the L178H mutant forms fibrils of a diameter of 10 nm that ranges in length from 30 to 120 nm. JLR These results show that apoA-I, known for its dynamic properties, has the ability to form multiple fibrillar conformations, which may play a role in the tissue-specific deposition of the individual variants.
  •  
41.
  • Piecha, D, et al. (författare)
  • Matrilin-2, a large, oligomeric matrix protein, is expressed by a great variety of cells and forms fibrillar networks
  • 1999
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 274:19, s. 13353-13361
  • Tidskriftsartikel (refereegranskat)abstract
    • Matrilin-2 is a member of the protein superfamily with von Willebrand factor type A-like modules. Mouse matrilin-2 cDNA fragments were expressed in 293-EBNA cells, and the protein was purified, characterized, and used to immunize rabbits. The affinity-purified antiserum detects matrilin-2 in dense and loose connective tissue structures, subepithelial connective tissue of the skin and digestive tract, specialized cartilages, and blood vessel walls. In situ hybridization of 35S-labeled riboprobes localizes the matrilin-2 mRNA to fibroblasts of dermis, tendon, ligaments, perichondrium, and periosteum; connective tissue elements in the heart; smooth muscle cells; and epithelia and loose connective tissue cells of the alimentary canal and respiratory tract. RNA blot hybridization and immunoblotting revealed both matrilin-2 mRNA and protein in cultures of a variety of cell types, confirming the tissue distribution. Alternative splicing affects a module unique for matrilin-2 in all of the above RNA sources. SDS-polyacrylamide gel electrophoresis and electron microscopy reveals matrilin-2 from tissue extracts and cell line cultures as a mixture of mono-, di-, tri-, and tetramers. Matrilin-2 is substituted with N-linked oligosaccharides but not with glycosaminoglycans. Because of other, yet unidentified, cell-type dependent posttranslational modifications, the monomer is heterogeneous in size. Immunofluorescence showed that matrilin-2 functions by forming an extracellular, filamentous network.
  •  
42.
  • Piecha, D, et al. (författare)
  • Matrilin-2 interacts with itself and with other extracellular matrix proteins
  • 2002
  • Ingår i: Biochemical Journal. - 0264-6021. ; 367:3, s. 715-721
  • Tidskriftsartikel (refereegranskat)abstract
    • Matrilin-2 is a component of extracellular filamentous networks. To study the interactions by which it can be integrated into such assemblies, full-length and truncated forms of matrilin-2 were recombinantly expressed in HEK-293 cells and purified from conditioned medium. The recombinant proteins, when used in interaction assays, showed affinity to matrilin-2 itself, but also to other collagenous and non-collagenous extracellular matrix proteins. The interaction between matrilin-2 and collagen I was studied in greater detail and could be shown to occur at distinct sites on the collagen I molecule and to have a K-D of about 3 x 10(-8) M. Interactions with some non-collagenous protein ligands were even stronger, with matrilin-2 binding to fibrillin-2, fibronectin and laminin-1-nidogen-1 complexes, with K-D values in the range of 10(-8)-10(-11) M. Co-localization of matrilin-2 with these ligands in the dermal-epidermal basement membrane, in the microfibrils extending from the basement membrane into the dermis, and in the dermal extracellular matrix, indicates a physiological relevance of the interactions in the assembly of supramolecular extracellular matrix structures.
  •  
43.
  • Purhonen, J, et al. (författare)
  • Ketogenic diet attenuates hepatopathy in mouse model of respiratory chain complex III deficiency caused by a Bcs1l mutation
  • 2017
  • Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1, s. 957-
  • Tidskriftsartikel (refereegranskat)abstract
    • Mitochondrial disorders are among the most prevalent inborn errors of metabolism but largely lack treatments and have poor outcomes. High-fat, low-carbohydrate ketogenic diets (KDs) have shown beneficial effects in mouse models of mitochondrial myopathies, with induction of mitochondrial biogenesis as the suggested main mechanism. We fed KD to mice with respiratory chain complex III (CIII) deficiency and progressive hepatopathy due to mutated BCS1L, a CIII assembly factor. The mutant mice became persistently ketotic and tolerated the KD for up to 11 weeks. Liver disease progression was attenuated by KD as shown by delayed fibrosis, reduced cell death, inhibition of hepatic progenitor cell response and stellate cell activation, and normalization of liver enzyme activities. Despite no clear signs of increased mitochondrial biogenesis in the liver, CIII assembly and activity were improved and mitochondrial morphology in hepatocytes normalized. Induction of hepatic glutathione transferase genes and elevated total glutathione level were normalized by KD. Histological findings and transcriptome changes indicated modulation of liver macrophage populations by the mutation and the diet. These results reveal a striking beneficial hepatic response to KD in mice with mitochondrial hepatopathy and warrant further investigations of dietary modification in the management of these conditions in patients.
  •  
44.
  • Påhlman, Lisa, et al. (författare)
  • Thrombin activatable fibrinolysis inhibitor binds to Streptococcus pyogenes by interacting with collagen-like surface proteins A and B.
  • 2007
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 282:34, s. 24873-24881
  • Tidskriftsartikel (refereegranskat)abstract
    • Regulation of proteolysis is a critical element of the host immune system and plays an important role in the induction of pro- and anti-inflammatory reactions in response to infection. Some bacterial species take advantage of these processes and recruit host proteinases to their surface in order to counteract the host attack. Here we show that Thrombin-activatable Fibrinolysis Inhibitor (TAFI), a zinc-dependent procarboxypeptidase, binds to the surface of group A streptococci of an M41 serotype. The interaction is mediated by the streptococcal collagen-like surface proteins A and B (Sc1A and Sc1B), and the streptococcal-associated TAFI is then processed at the bacterial surface via plasmin and thrombin-thrombomodulin. These findings suggest an important role for TAFI in the modulation of host responses by streptococci.
  •  
45.
  • Schaar, Viveka, et al. (författare)
  • Multicomponent Moraxella catarrhalis outer membrane vesicles induce an inflammatory response and are internalized by human epithelial cells.
  • 2011
  • Ingår i: Cellular Microbiology. - : Hindawi Limited. - 1462-5814. ; Dec, s. 432-449
  • Tidskriftsartikel (refereegranskat)abstract
    • Moraxella catarrhalis is an emerging human respiratory pathogen in patients with chronic obstructive pulmonary disease (COPD) and in children with acute otitis media. The specific secretion machinery known as outer membrane vesicles (OMVs) is a mechanism by which Gram-negative pathogens interact with host cells during infection. We identified 57 proteins in M. catarrhalis OMVs using a proteomics approach combining two-dimensional SDS-PAGE and MALDI-TOF mass spectrometry analysis. The OMVs contained known surface proteins such as ubiquitous surface proteins (Usp) A1/A2, and Moraxella IgD-binding protein (MID). Most of the proteins are adhesins/virulence factors triggering the immune response, but also aid bacteria to evade the host defence. FITC-stained OMVs bound to lipid raft domains in alveolar epithelial cells and were internalized after interaction with Toll-like receptor 2 (TLR2), suggesting a delivery to the host tissue of a large and complex group of OMV-attributed proteins. Interestingly, OMVs modulated the pro-inflammatory response in epithelial cells, and UspA1-bearing OMVs were found to specifically downregulate the reaction. When mice were exposed to OMVs, a pulmonary inflammation was clearly seen. Our findings indicate that Moraxella OMVs are highly biologically active, transport main bacterial virulence factors and may modulate the epithelial pro-inflammatory response.
  •  
46.
  • Sengle, G, et al. (författare)
  • Identification and characterization of AMACO, a new member of the von Willebrand factor A-like domain protein superfamily with a regulated expression in the kidney
  • 2003
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:50, s. 50240-50249
  • Tidskriftsartikel (refereegranskat)abstract
    • The genes coding for human and mouse AMACO, an extracellular matrix protein containing VWA-like domains related to those in MAtrilins and COllagens, were detected in databases, the cDNAs were cloned, and the primary structures were deduced from the nucleotide sequences. The genes consist of 14 exons and have a similar exon/intron organization. The protein consists of a signal peptide sequence, an N-terminal VWA domain connected to two additional, tandem VWA domains by a cysteine-rich sequence and an epidermal growth factor (EGF)-like domain. The C terminus is made up of another EGF-like domain followed by a unique sequence present in mouse, but absent in human. The predicted molecular weight of the proteins is 79,485 in human and 83,024 in mouse. Full-length AMACO was expressed in 293-EBNA cells, purified by use of an affinity tag and subjected to biochemical characterization. Both monomers and aggregates of AMACO were recovered, as shown by electron microscopy and SDS-PAGE. AMACO was found in the media of a variety of established cell lines of both fibroblast and epithelial origin. In the matrix formed by 293-EBNA cells overexpressing the protein, AMACO was deposited in patchy structures that were often cell-associated. Affinity-purified antibodies detect expression in cartilage and expression associated with certain basement membranes. In the kidney of adult mice, a second promoter located in intron 4 is active. If the resulting transcript is translated it could not yield a secreted protein because of the lack of a signal peptide sequence. The developmental switch from an AMACO mRNA, expressed by the newborn kidney, to the truncated transcript found in the adult kidney indicates an unusual regulation of AMACO expression.
  •  
47.
  • Spanou, Chara E.S., et al. (författare)
  • Targeting of bone morphogenetic protein complexes to heparin/heparan sulfate glycosaminoglycans in bioactive conformation
  • 2023
  • Ingår i: FASEB Journal. - 0892-6638. ; 37:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Bone morphogenetic proteins (BMP) are powerful regulators of cellular processes such as proliferation, differentiation, and apoptosis. However, the specific molecular requirements controlling the bioavailability of BMPs in the extracellular matrix (ECM) are not yet fully understood. Our previous work showed that BMPs are targeted to the ECM as growth factor-prodomain (GF-PD) complexes (CPLXs) via specific interactions of their PDs. We showed that BMP-7 PD binding to the extracellular microfibril component fibrillin-1 renders the CPLXs from an open, bioactive V-shape into a closed, latent ring shape. Here, we show that specific PD interactions with heparin/heparan sulfate glycosaminoglycans (GAGs) allow to target and spatially concentrate BMP-7 and BMP-9 CPLXs in bioactive V-shape conformation. However, targeting to GAGs may be BMP specific, since BMP-10 GF and CPLX do not interact with heparin. Bioactivity assays on solid phase in combination with interaction studies showed that the BMP-7 PD protects the BMP-7 GF from inactivation by heparin. By using transmission electron microscopy, molecular docking, and site-directed mutagenesis, we determined the BMP-7 PD-binding site for heparin. Further, fine-mapping of the fibrillin-1-binding site within the BMP-7 PD and molecular modeling showed that both binding sites are mutually exclusive in the open V- versus closed ring-shape conformation. Together, our data suggest that targeting exquisite BMP PD-binding sites by extracellular protein and GAG scaffolds integrates BMP GF bioavailability in a contextual manner in development, postnatal life, and connective tissue disease.
  •  
48.
  • Stjärne Aspelund, A., et al. (författare)
  • Acetic acid as a decontamination method for sink drains in a nosocomial outbreak of metallo-β-lactamase-producing Pseudomonas aeruginosa
  • 2016
  • Ingår i: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701. ; 94:1, s. 13-20
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Pseudomonas aeruginosa may colonize water systems via biofilm formation. In hospital environments, contaminated sinks have been associated with nosocomial transmission. Here we describe a prolonged outbreak of a metallo-β-lactamase-producing P. aeruginosa (Pae-MBL) associated with sink drains, and propose a previously unreported decontamination method with acetic acid. Aim To describe a nosocomial outbreak of Pae-MBL associated with hospital sink drains and to evaluate acetic acid as a decontamination method. Methods The outbreak was investigated by searching the microbiology database, microbiological sampling and strain typing. Antibacterial and antibiofilm properties of acetic acid were evaluated in vitro. Pae-MBL-positive sinks were treated with 24% acetic acid once weekly and monitored with repeated cultures. Findings Fourteen patients with positive cultures for Pae-MBL were identified from 2008 to 2014. The patients had been admitted to three wards, where screening discovered Pae-MBL in 12 sink drains located in the patient bathrooms. Typing of clinical and sink drain isolates revealed identical or closely related strains. Pae-MBL biofilm was highly sensitive to acetic acid with a minimum biofilm eradication concentration of 0.75% (range: 0.19–1.5). Weekly treatment of colonized sink drains with acetic acid resulted in negative cultures and terminated transmission. Conclusion Acetic acid is highly effective against Pae-MBL biofilms, and may be used as a simple method to decontaminate sink drains and to prevent nosocomial transmission.
  •  
49.
  • Svensson, Katrin, et al. (författare)
  • Exosome uptake depends on ERK1/2-heat shock protein 27 signalling and lipid raft-mediated endocytosis negatively regulated by caveolin-1.
  • 2013
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 288:24, s. 17713-17724
  • Tidskriftsartikel (refereegranskat)abstract
    • The role of exosomes in cancer can be inferred from the observation that they transfer tumor cell derived genetic material and signalling proteins, resulting in e.g. increased tumor angiogenesis and metastasis. However, the membrane transport mechanisms and the signalling events involved in the uptake of these virus-like particles remain ill-defined. We now report that internalization of exosomes derived from glioblastoma (GBM) cells involves nonclassical, lipid raft-dependent endocytosis. Importantly, we show that the lipid raft associated protein caveolin-1 (CAV1), in analogy with its previously described role in virus uptake, negatively regulates the uptake of exosomes. We find that exosomes induce the phosphorylation of several downstream targets known to associate with lipid rafts as signalling and sorting platforms, such as extracellular signal-regulated kinase-1/2 (ERK1/2) and heat shock protein 27 (HSP27). Interestingly, exosome uptake appears dependent on unperturbed ERK1/2-HSP27 signalling, and ERK1/2 phosphorylation is under negative influence by CAV1 during internalization of exosomes. These findings significantly advance our general understanding of exosome-mediated uptake and offer potential strategies for how this pathway may be targeted through modulation of CAV1 expression and ERK1/2 signaling.
  •  
50.
  • Tati, Ramesh, et al. (författare)
  • Biological wound matrices with native dermis-like collagen efficiently modulate protease activity
  • 2018
  • Ingår i: Journal of Wound Care. - : Mark Allen Group. - 0969-0700 .- 2052-2916. ; 27:4, s. 199-209
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: When the delicate balance between catabolic and anabolic processes is disturbed for any reason, the healing process can stall, resulting in chronic wounds. In chronic wound pathophysiology, proteolytic imbalance is implicated due to elevated protease levels mediating tissue damage. Hence, it is important to design appropriate wound treatments able to control and modulate protease activity directly at the host/biomaterial interface. Here, we investigate collagen-based wound dressings with the focus on their potential to adsorb and inactivate tissue proteases. Method: We examined the effect of six collagen-based dressings on their ability to adsorb and inactivate different granulocyte proteases, plasmin, human neutrophil elastase (HLE), and matrix metalloproteases (MMP)-1, -2, -8, and -9, by an integrated approach including immunoelectron microscopy. Results: We observed a reduction of the proteolytic activities of plasmin, HLE, and MMP-1, -2, -8, and -9, both on the biomaterial surface and in human chronic wound fluid. The most pronounced effect was observed in collagen-based dressings, with the highest content of native collagen networks resembling dermis structures. Conclusion: Our data suggest that this treatment strategy might be beneficial for the chronic wound environment, with the potential to promote improved wound healing. Declaration of interest: The authors have no conflicts of interest with the contents of this article. This work was supported by grants from the Swedish Research Council (project 7480), the Swedish Foundation for Strategic Research (K2014-56X-13413-15-3), the Foundations of Crafoord, Johan and Greta Kock, Alfred Österlund, King Gustav V Memorial Fund, and the Medical Faculty at Lund University.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 56

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy