| 1. |
- Aspberg, A., et al.
(författare)
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Cartilage oligomeric matrix protein forms protein complexes with synovial lubricin via non-covalent and covalent interactions
- 2017
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 25:9, s. 1496-1504
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Understanding the cartilage surface structure, lost in arthritic disease, is essential for developing strategies to effectively restore it. Given that adherence of the lubricating protein, lubricin, to the cartilage surface is critical for boundary lubrication, an interaction with cartilage oligomeric matrix protein (COMP) was investigated. COMP, an abundant cartilage protein, is known to be important for matrix formation. Design: Synovial fluid (SF) from arthritic patients was used to detect possible COMP-lubricin complexes by immunological methods. Recombinant (RC) COMP and lubricin fragments were expressed to characterize this bonding and mass spectrometry employed to specifically identify the cysteines involved in inter-protein disulfide bonds. Results: COMP-lubricin complexes were identified in the SF of arthritic patients by Western blot, co-immunoprecipitation and sandwich ELISA. RC fragment solid-phase binding assays showed that the C-terminal (amino acids (AA) 518-757) of COMP bound non-covalently to the N-terminal of lubricin (AA 105-202). Mass spectrometry determined that although cysteines throughout COMP were involved in binding with lubricin, the cysteines in lubricin were primarily focused to an N-terminal region (AA 64-86). The close proximity of the non-covalent and disulfide binding domains on lubricin suggest a two-step mechanism to strongly bind lubricin to COMP. Conclusion: These data demonstrate that lubricin forms a complex network with COMP involving both non-covalent and covalent bonds. This complex between lubricin and the cartilage protein COMP can be identified in the SF of patients with arthritis conditions including osteoarthritis (OA) and rheumatoid arthritis (RA). (C) 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
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| 2. |
- Coral, Daniel E, et al.
(författare)
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A phenome-wide comparative analysis of genetic discordance between obesity and type 2 diabetes
- 2023
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Ingår i: Nature Metabolism. - : Springer Science and Business Media LLC. - 2522-5812. ; 5:2, s. 237-247
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Tidskriftsartikel (refereegranskat)abstract
- Obesity and type 2 diabetes are causally related, yet there is considerable heterogeneity in the consequences of both conditions and the mechanisms of action are poorly defined. Here we show a genetic-driven approach defining two obesity profiles that convey highly concordant and discordant diabetogenic effects. We annotate and then compare association signals for these profiles across clinical and molecular phenotypic layers. Key differences are identified in a wide range of traits, including cardiovascular mortality, fat distribution, liver metabolism, blood pressure, specific lipid fractions and blood levels of proteins involved in extracellular matrix remodelling. We find marginal differences in abundance of Bacteroidetes and Firmicutes bacteria in the gut. Instrumental analyses reveal prominent causal roles for waist-to-hip ratio, blood pressure and cholesterol content of high-density lipoprotein particles in the development of diabetes in obesity. We prioritize 17 genes from the discordant signature that convey protection against type 2 diabetes in obesity, which may represent logical targets for precision medicine approaches.
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| 3. |
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| 4. |
- Eloranta, Maija-Leena, et al.
(författare)
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Type I interferon system activation and association with disease manifestations in systemic sclerosis
- 2010
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 69:7, s. 1396-1402
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To study the presence of interferogenic autoantibodies in systemic sclerosis (SSc) and their correlation with clinical manifestations, serum levels of interferon alpha (IFNalpha) and chemokines of importance in the disease process. METHODS: Peripheral blood mononuclear cells (PBMCs) or purified plasmacytoid dendritic cells (pDCs) from healthy donors were stimulated with sera from patients with SSc (n=70) or healthy individuals (n=30), together with necrotic or apoptotic cell material. The IFNalpha produced and serum levels of IFNalpha, IFN-inducible protein-10 (IP-10)/chemokine (C-X-C motif) ligand 10, monocyte chemoattractant protein-1 (MCP-1)/(C-C motif) ligand-2 (CCL-2), macrophage inflammatory protein-1alpha (MIP-1alpha)/CCL-3 and RANTES/CCL-5 were measured and correlated with the presence of autoantibodies and clinical manifestations in the patients with SSc. RESULTS: Sera from both diffuse SSc and limited SSc contained interferogenic antibodies, which correlated with the presence of anti-ribonucleoprotein and anti-Sjögren syndrome antigen autoantibodies. The pDCs were responsible for the IFNalpha production which required interaction with FcgammaRII and endocytosis. Increased serum levels of IP-10 were associated with vascular manifestations such as cardiac involvement (p=0.027) and pulmonary arterial hypertension (p=0.036). Increased MCP-1 or IFNalpha serum levels were associated with lung fibrosis (p=0.019 and 0.048, respectively). Digital ulcers including digital loss were associated with increased serum levels of IFNalpha (p=0.029). CONCLUSION: An activated type I IFN system previously seen in several other systemic autoimmune diseases is also present in SSc and may contribute to the vascular pathology and affect the profibrotic process.
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| 5. |
- Flowers, Sarah A., et al.
(författare)
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Lubricin binds cartilage proteins, cartilage oligomeric matrix protein, fibronectin and collagen II at the cartilage surface
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Lubricin, a heavily O-glycosylated protein, is essential for boundary lubrication of articular cartilage. Strong surface adherence of lubricin is required given the extreme force it must withstand. Disulfide bound complexes of lubricin and cartilage oligomeric matrix protein (COMP) have recently been identified in arthritic synovial fluid suggesting they may be lost from the cartilage surface in osteoarthritis and inflammatory arthritis. This investigation was undertaken to localise COMP-lubricin complexes within cartilage and investigate if other cartilage proteins are involved in anchoring lubricin to the joint. Immunohistochemical analysis of human cartilage biopsies showed lubricin and COMP co-localise to the cartilage surface. COMP knockout mice, however, presented with a lubricin layer on the articular cartilage leading to the further investigation of additional lubricin binding mechanisms. Proximity ligation assays (PLA) on human cartilage biopsies was used to localise additional lubricin binding partners and demonstrated that lubricin bound COMP, but also fibronectin and collagen II on the cartilage surface. Fibronectin and collagen II binding to lubricin was confirmed and characterised by solid phase binding assays with recombinant lubricin fragments. Overall, COMP, fibronectin and collagen II bind lubricin, exposed on the articular cartilage surface suggesting they may be involved in maintaining essential boundary lubrication.
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| 6. |
- Garcia-Calzon, Sonia, et al.
(författare)
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Epigenetic markers associated with metformin response and intolerance in drug-naive patients with type 2 diabetes
- 2020
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Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 12:561
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Tidskriftsartikel (refereegranskat)abstract
- Metformin is the first-line pharmacotherapy for managing type 2 diabetes (T2D). However, many patients with T2D do not respond to or tolerate metformin well. Currently, there are no phenotypes that successfully predict glycemic response to, or tolerance of, metformin. We explored whether blood-based epigenetic markers could discriminate metformin response and tolerance by analyzing genome-wide DNA methylation in drug-naive patients with T2D at the time of their diagnosis. DNA methylation of 11 and 4 sites differed between glycemic responders/nonresponders and metformin-tolerant/intolerant patients, respectively, in discovery and replication cohorts. Greater methylation at these sites associated with a higher risk of not responding to or not tolerating metformin with odds ratios between 1.43 and 3.09 per 1-SD methylation increase. Methylation risk scores (MRSs) of the 11 identified sites differed between glycemic responders and nonresponders with areas under the curve (AUCs) of 0.80 to 0.98. MRSs of the 4 sites associated with future metformin intolerance generated AUCs of 0.85 to 0.93. Some of these blood-based methylation markers mirrored the epigenetic pattern in adipose tissue, a key tissue in diabetes pathogenesis, and genes to which these markers were annotated to had biological functions in hepatocytes that altered metformin-related phenotypes. Overall, we could discriminate between glycemic responders/nonresponders and participants tolerant/intolerant to metformin at diagnosis by measuring blood-based epigenetic markers in drug-naive patients with T2D. This epigenetics-based tool may be further developed to help patients with T2D receive optimal therapy.
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| 7. |
- García-Calzón, Sonia, et al.
(författare)
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Epigenetic markers associated with metformin response and intolerance in drug-naïve patients with type 2 diabetes
- 2020
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Ingår i: Science Translational Medicine. - 1946-6234. ; 12:561
-
Tidskriftsartikel (refereegranskat)abstract
- Metformin is the first-line pharmacotherapy for managing type 2 diabetes (T2D). However, many patients with T2D do not respond to or tolerate metformin well. Currently, there are no phenotypes that successfully predict glycemic response to, or tolerance of, metformin. We explored whether blood-based epigenetic markers could discriminate metformin response and tolerance by analyzing genome-wide DNA methylation in drug-naïve patients with T2D at the time of their diagnosis. DNA methylation of 11 and 4 sites differed between glycemic responders/nonresponders and metformin-tolerant/intolerant patients, respectively, in discovery and replication cohorts. Greater methylation at these sites associated with a higher risk of not responding to or not tolerating metformin with odds ratios between 1.43 and 3.09 per 1-SD methylation increase. Methylation risk scores (MRSs) of the 11 identified sites differed between glycemic responders and nonresponders with areas under the curve (AUCs) of 0.80 to 0.98. MRSs of the 4 sites associated with future metformin intolerance generated AUCs of 0.85 to 0.93. Some of these blood-based methylation markers mirrored the epigenetic pattern in adipose tissue, a key tissue in diabetes pathogenesis, and genes to which these markers were annotated to had biological functions in hepatocytes that altered metformin- related phenotypes. Overall, we could discriminate between glycemic responders/nonresponders and participants tolerant/ intolerant to metformin at diagnosis by measuring blood-based epigenetic markers in drug-naïve patients with T2D. This epigenetics-based tool may be further developed to help patients with T2D receive optimal therapy.
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| 8. |
- Gheibi, Sevda, et al.
(författare)
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Reduced Expression Level of Protein Phosphatase PPM1E Serves to Maintain Insulin Secretion in Type 2 Diabetes
- 2023
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797. ; 72:4, s. 455-466
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Tidskriftsartikel (refereegranskat)abstract
- Reversible phosphorylation is an important regulatory mechanism. Regulation of protein phosphorylation in β-cells has been extensively investigated, but less is known about protein dephosphorylation. To understand the role of protein dephosphorylation in β-cells and type 2 diabetes (T2D), we first examined mRNA expression of the type 2C family (PP2C) of protein phosphatases in islets from T2D donors. Phosphatase expression overall was changed in T2D, and that of PPM1E was the most markedly downregulated. PPM1E expression correlated inversely with HbA1c. Silencing of PPM1E increased glucose-stimulated insulin secretion (GSIS) in INS-1 832/13 cells and/or islets from patients with T2D, whereas PPM1E overexpression decreased GSIS. Increased GSIS after PPM1E silencing was associated with decreased oxidative stress, elevated cytosolic Ca2+ levels and ATP to ADP ratio, increased hyperpo-larization of the inner mitochondrial membrane, and phosphorylation of CaMKII, AMPK, and acetyl-CoA car-boxylase. Silencing of PPM1E, however, did not change insulin content. Increased GSIS, cell viability, and activation of AMPK upon metformin treatment in β-cells were observed upon PPM1E silencing. Thus, protein de-phosphorylation via PPM1E abrogates GSIS. Conse-quently, reduced PPM1E expression in T2D may be a compensatory response of β-cells to uphold insulin secretion under metabolic duress. Targeting PPM1E in β-cells may thus represent a novel therapeutic strategy for treatment of T2D.
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| 9. |
- Huang, M., et al.
(författare)
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CRISPR editing of the PPARGC1A Gly482ser (rs8192678) polymorphism in human white adipose cells shows differential effects on mitochondrial function and adipogenesis.
- 2021
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 64:Suppl 1, s. 159-159
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Konferensbidrag (refereegranskat)abstract
- Background and aims: PPARGC1A encodes PGC-1α (peroxisome proliferator-activated receptor γ coactivator 1-α), a central regulator of energy metabolism and mitochondrial function. A common polymorphism in PPARGC1A (rs8192678, C/T, Gly482Ser) has been associated with obesity and related metabolic disorders, but no published functional studies have investigated direct allele-specific effects in adipocyte biology. Materials and methods: We used CRISPR-Cas9 to perform allele switching (C-to-T or T-to-C) at rs8192678 in isogenic human pre-adipocyte white adipose tissue (hWAT) cell line; we then evaluated the allelic effects at rs8192678 on adipogenic differentiation and mitochondrial function. Accordingly, single-cell clones were expanded and screened to obtain homozygous T/T (482Ser) and C/C (482Gly) isogenic cell populations. The effect of the allele editing on white adipocyte differentiation and on mitochondrial function was then studied in three cell populations of the respective genotype. In ongoing experiments, CRISPR/Cas9 was also used to append a luciferase tag to C/C and in T/T cells. The luciferase will be used as a reporter for the endogenously expressed PGC-1 protein stability, and will therefore provide insights into mechanisms by which rs8192678 alleles affect PGC-1 activity. Results (see figure): At the end of the differentiation protocol the C/C adipocytes were apparently less Oil-Red-O positive than T/T adipocytes under optical microscopy, they had 78.5% lower triglyceride content (p<0.0001, n=9), and lower expression of adipogenic markers (all markers p<0.0001, n=3). Furthermore, C/C adipocytes had lower mitochondrial content (p<0.001, n=9), which coincided with decreased oxygen consumption rate (OCR) at basal (p<0.0001, n=3) and maximal respiration (p<0.0001, n=3). Also, C/C adipocytes had lower ATP-linked OCR (p<0.0001, n=3). Conclusion: Our data showcases discriminatory causal effects of the two rs8192678 alleles in adipocytes. The C allele confers lower PPARGC1A expression, and consequential impaired adipocyte differentiation, at least in part due to disrupted mitochondrial biosynthesis and function. Our study is the first to give experimental insights into the molecular mechanisms behind observational epidemiological studies the Gly482Ser variant and obesity and metabolic disorders
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| 10. |
- Huang, Mi, et al.
(författare)
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Engineered allele substitution at PPARGC1A rs8192678 alters human white adipocyte differentiation, lipogenesis, and PGC-1α content and turnover
- 2023
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Ingår i: Diabetologia. - 1432-0428. ; 66:7, s. 1289-1305
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesisPPARGC1A encodes peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), a central regulator of energy metabolism and mitochondrial function. A common polymorphism in PPARGC1A (rs8192678, C/T, Gly482Ser) has been associated with obesity and related metabolic disorders, but no published functional studies have investigated direct allele-specific effects in adipocyte biology. We examined whether rs8192678 is a causal variant and reveal its biological function in human white adipose cells.MethodsWe used CRISPR-Cas9 genome editing to perform an allelic switch (C-to-T or T-to-C) at rs8192678 in an isogenic human pre-adipocyte white adipose tissue (hWAs) cell line. Allele-edited single-cell clones were expanded and screened to obtain homozygous T/T (Ser482Ser), C/C (Gly482Gly) and heterozygous C/T (Gly482Ser) isogenic cell populations, followed by functional studies of the allele-dependent effects on white adipocyte differentiation and mitochondrial function.ResultsAfter differentiation, the C/C adipocytes were visibly less BODIPY-positive than T/T and C/T adipocytes, and had significantly lower triacylglycerol content. The C allele presented a dose-dependent lowering effect on lipogenesis, as well as lower expression of genes critical for adipogenesis, lipid catabolism, lipogenesis and lipolysis. Moreover, C/C adipocytes had decreased oxygen consumption rate (OCR) at basal and maximal respiration, and lower ATP-linked OCR. We determined that these effects were a consequence of a C-allele-driven dysregulation of PGC-1α protein content, turnover rate and transcriptional coactivator activity.Conclusions/interpretationOur data show allele-specific causal effects of the rs8192678 variant on adipogenic differentiation. The C allele confers lower levels of PPARGC1A mRNA and PGC-1α protein, as well as disrupted dynamics of PGC-1α turnover and activity, with downstream effects on cellular differentiation and mitochondrial function. Our study provides the first experimentally deduced insights on the effects of rs8192678 on adipocyte phenotype.
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| 11. |
- Huang, Mi, et al.
(författare)
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Human Genetic Variation at rs10071329 Correlates with Adiposity-related Traits, Modulates PPARGC1B Expression, and Alters Brown Adipocyte Function
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Ingår i: Diabetes. - 1939-327X.
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Tidskriftsartikel (refereegranskat)abstract
- Human genetic variation in PPARGC1B has been associated with adiposity, but the genetic variants that affect PPARGC1B expression have not been experimentally determined. Here, guided by previous observational data, we used CRISPR/Cas9 to scarlessly edit the alleles of the candidate causal genetic variant rs10071329 in a human brown adipocyte cell line (hBAs). Switching the rs10071329 genotype from A/A to G/G enhanced PPARGC1B expression throughout the adipogenic differentiation, identifying rs10071329 as a cis-eQTL. The higher PPARGC1B expression in G/G cells coincided with greater accumulation of triglycerides, and higher expression of mitochondria-encoded genes, but without significant effects on adipogenic marker expression. Furthermore, G/G cells had improved basal- and norepinephrine-stimulated mitochondrial respiration, possibly relating to enhanced mitochondrial gene expression. The G/G cells also exhibited increased norepinephrine-stimulated glycerol release, indicating improved lipolysis. Altogether, our results showed that rs10071329 is a cis-eQTL, with the G/G genotype conferring enhanced PPARGC1B expression, with consequent improved mitochondrial function and response to norepinephrine in brown adipocytes. This genetic variant, and as yet undetermined eQTLs, at PPARGC1B could prove useful in genotype-based precision medicine for obesity treatment.
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| 12. |
- Huang, Mi, et al.
(författare)
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Identification of a weight loss-associated causal eQTL in MTIF3 and the effects of MTIF3 deficiency on human adipocyte function
- 2023
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Ingår i: eLife. - 2050-084X.
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variation at the MTIF3 (Mitochondrial Translational Initiation Factor 3) locus has been robustly associated with obesity in humans, but the functional basis behind this association is not known. Here, we applied luciferase reporter assay to map potential functional variants in the haplotype block tagged by rs1885988 and used CRISPR-Cas9 to edit the potential functional variants to confirm the regulatory effects on MTIF3 expression. We further conducted functional studies on MTIF3-deficient differentiated human white adipocyte cell line (hWAs-iCas9), generated through inducible expression of CRISPR-Cas9 combined with delivery of synthetic MTIF3-targeting guide RNA. We demonstrate that rs67785913-centered DNA fragment (in LD with rs1885988, r2 > 0.8) enhances transcription in a luciferase reporter assay, and CRISPR-Cas9-edited rs67785913 CTCT cells show significantly higher MTIF3 expression than rs67785913 CT cells. Perturbed MTIF3 expression led to reduced mitochondrial respiration and endogenous fatty acid oxidation, as well as altered expression of mitochondrial DNA-encoded genes and proteins, and disturbed mitochondrial OXPHOS complex assembly. Furthermore, after glucose restriction, the MTIF3 knockout cells retained more triglycerides than control cells. This study demonstrates an adipocyte function-specific role of MTIF3, which originates in the maintenance of mitochondrial function, providing potential explanations for why MTIF3 genetic variation at rs67785913 is associated with body corpulence and response to weight loss interventions.
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| 13. |
- Huang, Shan, et al.
(författare)
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Cathepsin g Degrades Both Glycosylated and Unglycosylated Regions of Lubricin, a Synovial Mucin
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Lubricin (PRG4) is a mucin type protein that plays an important role in maintaining normal joint function by providing lubrication and chondroprotection. Improper lubricin modification and degradation has been observed in idiopathic osteoarthritis (OA), while the detailed mechanism still remains unknown. We hypothesized that the protease cathepsin G (CG) may participate in degrading lubricin in synovial fluid (SF). The presence of endogenous CG in SF was confirmed in 16 patients with knee OA. Recombinant human lubricin (rhPRG4) and native lubricin purified from the SF of patients were incubated with exogenous CG and lubricin degradation was monitored using western blot, staining by Coomassie or Periodic Acid-Schiff base in gels, and with proteomics. Full length lubricin (∼300 kDa), was efficiently digested with CG generating a 25-kDa protein fragment, originating from the densely glycosylated mucin domain (∼250 kDa). The 25-kDa fragment was present in the SF from OA patients, and the amount was increased after incubation with CG. A CG digest of rhPRG4 revealed 135 peptides and 72 glycopeptides, and confirmed that the protease could cleave in all domains of lubricin, including the mucin domain. Our results suggest that synovial CG may take part in the degradation of lubricin, which could affect the pathological decrease of the lubrication in degenerative joint disease. © 2020, The Author(s).
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| 14. |
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| 15. |
- Huijbers, Elisabeth J. M., et al.
(författare)
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Vaccination against the extra domain-B of fibronectin as a novel tumor therapy
- 2010
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 24:11, s. 4535-4544
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Tidskriftsartikel (refereegranskat)abstract
- Monoclonal antibody-based therapies have made an important contribution to current treatment strategies for cancer and autoimmune disease. However, the cost for these new drugs puts a significant strain on the health-care economy, resulting in limited availability for patients. Therapeutic vaccination, defined as induction of immunity against a disease-related self-molecule, is therefore an attractive alternative. To analyze the potential of such an approach, we have developed a vaccine against the extra domain-B (ED-B) of fibronectin. This 91-aa domain, inserted by alternative splicing, is expressed during vasculogenesis in the embryo, but essentially undetectable under normal conditions in the adult. However, ED-B is highly expressed around angiogenic vasculature, such as in tumorigenesis. Here, we demonstrate that it is possible to break self-tolerance and induce a strong antibody response against ED-B by vaccination. Nineteen of 20 vaccinated mice responded with production of anti-ED-B antibodies and displayed a 70% reduction in tumor size compared to those lacking anti-ED-B antibodies. Analysis of the tumor tissue revealed that immunization against ED-B induced several changes, consistent with an attack by the immune system. These data show that tumor vascular antigens are highly interesting candidates for development of therapeutic vaccines targeting solid tumors.
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| 16. |
- Häger, Mattias, et al.
(författare)
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Cib2 binds integrin a7Bb1D and is reduced in laminin a2 chain deficient muscular dystrophy
- 2008
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 283:36, s. 24760-24769
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in the gene encoding laminin alpha 2 chain cause congenital muscular dystrophy type 1A. In skeletal muscle, laminin alpha 2 chain binds at least two receptor complexes: the dystrophin-glycoprotein complex and integrin alpha 7 beta 1. To gain insight into the molecular mechanisms underlying this disorder, we performed gene expression profiling of laminin alpha 2 chain-deficient mouse limb muscle. One of the down-regulated genes encodes a protein called Cib2 (calcium-and integrin-binding protein 2) whose expression and function is unknown. However, the closely related Cib1 has been reported to bind integrin alpha IIb and may be involved in outside-in-signaling in platelets. Since Cib2 might be a novel integrin alpha 7 beta 1-binding protein in muscle, we have studied Cib2 expression in the developing and adult mouse. Cib2 mRNA is mainly expressed in the developing central nervous system and in developing and adult skeletal muscle. In skeletal muscle, Cib2 colocalizes with the integrin alpha 7B subunit at the sarcolemma and at the neuromuscular and myotendinous junctions. Finally, we demonstrate that Cib2 is a calcium-binding protein that interacts with integrin alpha 7B beta 1D. Thus, our data suggest a role for Cib2 as a cytoplasmic effector of integrin alpha 7B beta 1D signaling in skeletal muscle.
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| 17. |
- Ishikawa, Yoshihiro, et al.
(författare)
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The endoplasmic reticulum-resident collagen chaperone Hsp47 interacts with and promotes the secretion of decorin, fibromodulin, and lumican
- 2018
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Ingår i: Journal of Biological Chemistry. - : AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC. - 0021-9258 .- 1083-351X. ; 293:35, s. 13707-13716
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Tidskriftsartikel (refereegranskat)abstract
- The build-up of diversified and tissue-specific assemblies of extracellular matrix (ECM) proteins depends on secreted and cell surface-located molecular arrays that coordinate ECM proteins into discrete designs. The family of small leucine-rich proteins (SLRPs) associates with and dictates the structure of fibrillar collagens, which form the backbone of most ECM types. However, whether SLRPs form complexes with proteins other than collagens is unclear. Here, we demonstrate that heat shock protein 47 (Hsp47), a well-established endoplasmic reticulum-resident collagen chaperone, also binds the SLRPs decorin, lumican, and fibromodulin with affinities comparable with that in the Hsp47-type I collagen interaction. Furthermore, we show that a lack of Hsp47 inhibits the cellular secretion of decorin and lumican. Our results expand the understanding of the concerted molecular interactions that control the secretion and organization of a functional collagenous ECM.
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| 18. |
- Kalamajski, Sebastian, et al.
(författare)
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Asporin competes with decorin for collagen binding, binds calcium and promotes osteoblast collagen mineralization
- 2009
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Ingår i: Biochemical Journal. - 0264-6021. ; 423, s. 53-59
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Tidskriftsartikel (refereegranskat)abstract
- The interactions of the ECM (extracellular matrix) protein asporin with ECM components have previously not been investigated. Here, we show that asporin binds collagen type I. This binding is inhibited by recombinant asporin fragment LRR (leucine-rich repeat) 10-12 and by full-length decorin, but not by biglycan. We demonstrate that the polyaspartate domain binds calcium and regulates hydroxyapatite formation in vitro. In the presence of asporin, the number of collagen nodules, and mRNA of osteoblastic markers Osterix and Runx2 were increased. Moreover, decorin or the collagen-binding asporin fragment LRR 10-12 inhibited the pro-osteoblastic activity of full-length asporin. Our results suggest that asporin and decorin compete for binding to collagen and that the polyaspartate in asporin directly regulates collagen mineralization. Therefore asporin has a role in osteoblast-driven collagen biomineralization activity. We also show that asporin can be expressed in Escherichia coli (Rosettagami (TM)) with correctly positioned cysteine bridges, and a similar system can possibly be used for the expression of other SLRPs (small LRR proteoglycans/proteins).
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| 19. |
- Kalamajski, Sebastian, et al.
(författare)
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Fibromodulin binds collagen type I via Glu-353 and Lys-355 in leucine-rich repeat 11
- 2007
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 282:37, s. 26740-26745
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Tidskriftsartikel (refereegranskat)abstract
- Fibromodulin belongs to the small leucine-rich repeat proteoglycan family, interacts with collagen type I, and controls collagen fibrillogenesis and assembly. Here, we show that a major fibromodulin-binding site for collagen type I is located in leucine-rich repeat 11 in the C terminus of the leucine-rich repeat domain. We identified Glu-353 and Lys-355 in repeat 11 as essential for binding, and the synthetic peptide RLDGNEIKR, including Glu-353 and Lys-355, inhibits the binding of fibromodulin to collagen in vitro. Fibromodulin and lumican compete for the same binding region on collagen, and fibromodulin can inhibit the binding of lumican to collagen type I. However, the peptide RLDGNEIKR does not inhibit the binding of lumican to collagen, suggesting separate but closely situated fibromodulin- and lumican-binding sites in collagen. The collagen-binding Glu-353 and Lys-355 residues in fibromodulin are exposed on the exterior of the beta-sheet-loop structure of the leucine-rich repeat, which resembles the location of interacting residues in other leucine-rich repeat proteins, e. g. decorin.
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| 20. |
- Kalamajski, Sebastian, et al.
(författare)
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Fibromodulin Interacts with Collagen Cross-linking Sites and Activates Lysyl Oxidase.
- 2016
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 291:15, s. 7951-60
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Tidskriftsartikel (refereegranskat)abstract
- The hallmark of fibrotic disorders is a highly cross-linked and dense collagen matrix, a property driven by the oxidative action of lysyl oxidase. Other fibrosis-associated proteins also contribute to the final collagen matrix properties, one of which is fibromodulin. Its interactions with collagen affect collagen cross-linking, packing, and fibril diameter. We investigated the possibility that a specific relationship exists between fibromodulin and lysyl oxidase, potentially imparting a specific collagen matrix phenotype. We mapped the fibromodulin-collagen interaction sites using the collagen II and III Toolkit peptide libraries. Fibromodulin interacted with the peptides containing the known collagen cross-linking sites and the MMP-1 cleavage site in collagens I and II. Interestingly, the interaction sites are closely aligned within the quarter-staggered collagen fibril, suggesting a multivalent interaction between fibromodulin and several collagen helices. Furthermore, we detected an interaction between fibromodulin and lysyl oxidase (a major collagen cross-linking enzyme) and mapped the interaction site to 12 N-terminal amino acids on fibromodulin. This interaction also increases the activity of lysyl oxidase. Together, the data suggest a fibromodulin-modulated collagen cross-linking mechanism where fibromodulin binds to a specific part of the collagen domain and also forms a complex with lysyl oxidase, targeting the enzyme toward specific cross-linking sites.
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| 21. |
- Kalamajski, Sebastian
(författare)
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Functions of small leucine-rich repeat proteoglycans in connective tissues
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biological properties of connective tissues rely heavily on collagen and its use in formation of extracellular networks (matrices) in which cells can live and move. To regulate the process of collagen matrix assembly, the cells secrete small leucine-rich repeat proteoglycans (SLRPs) that bind to collagen and influence its fibril formation. In this manner, fibromodulin - one of the SLRPs - can alter intermolecular cross-linking of collagen, which has long-term implications for the structural integrity of the connective tissue. Since SLRPs can bind to collagen in via different domains, and are expressed in different tissues, their regulation of collagen matrices is fine-tuned for the physiological requirements. For example, decorin and lumican interact with collagen using their central leucine-rich repeat domains, while fibromodulin makes use of its C-terminal domain. In addition, some SLRPs can inhibit each other's binding to collagen. These differences, together with the detailed knowledge on matrix protein interactions, can be useful to explain the development of connective tissues. In a longer time perspective, this knowledge could allow to manipulate fibrotic processes in pathological conditions like cancer or atherosclerosis - the two major causes of death in our society. The potential for such intervention is high, since fibromodulin is abundant in cancer stroma, raising its interstitial fluid pressure that hinders an efficient anti-cancer drug medication. Furthermore, fibromodulin is expressed in atherosclerotic plaques, regulating the growth of the fibrous cap and activity of smooth muscle cells. These observations validate further investigations into this field of connective tissue biology.
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| 22. |
- Kalamajski, Sebastian, et al.
(författare)
-
Genomic editing of metformin efficacy-associated genetic variants in SLC47A1 does not alter SLC47A1 expression
- 2022
-
Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 31:4, s. 491-498
-
Tidskriftsartikel (refereegranskat)abstract
- Several pharmacogenetics studies have identified an association between a greater metformin-dependent reduction in HbA1c levels and the minor A allele at rs2289669 in intron 10 of SLC47A1, encoding multidrug and toxin extrusion 1 (MATE1), a presumed metformin transporter. It is currently unknown if the rs2289669 locus is a cis-eQTL, which would validate its role as predictor of metformin efficacy. We looked at association between common genetic variants in the SLC47A1 gene region and HbA1c reduction after metformin treatment using locus-wise meta-analysis from the MetGen consortium. CRISPR-Cas9 was applied to perform allele editing of, or genomic deletion around, rs2289669 and of the closely linked rs8065082 in HepG2 cells. The genome-edited cells were evaluated for SLC47A1 expression and splicing. None of the common variants including rs2289669 showed significant association with metformin response. Genomic editing of either rs2289669 or rs8065082 did not alter SLC47A1 expression or splicing. Experimental and in silico analyses show that the rs2289669-containing haploblock does not appear to carry genetic variants that could explain its previously reported association with metformin efficacy.
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| 23. |
- Kalamajski, Sebastian, et al.
(författare)
-
Homologous sequence in lumican and fibromodulin LRR 5-7 competes for collagen binding.
- 2009
-
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 284:1, s. 534-539
-
Tidskriftsartikel (refereegranskat)abstract
- Lumican and fibromodulin compete for collagen type I binding in vitro and fibromodulin-deficient mice have four-fold more lumican in tendons. These observations indicate that homologous sequences in lumican and fibromodulin bind to collagen type I. Here, we demonstrate that lumican binding to collagen type I is mediated mainly by Asp-213 in LRR 7. The mutation D213N in lumican impairs interaction with collagen, and the lumican fragment spanning LRRs 5-7 is an efficient inhibitor of collagen binding. Also, the lumican LRR 7 sequence-based synthetic peptide CYLDNNKC inhibits the binding to collagen. Homologous collagen-binding site in fibromodulin, located in LRRs 5-7, inhibits the binding of lumican to collagen, and the mutation E251Q in this fibromodulin fragment does not inhibit the lumican-collagen binding. Lumican, but not the the D213N mutation, lowers the melting point and affects the packing of collagen fibrils.
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| 24. |
- Kalamajski, Sebastian, et al.
(författare)
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Increased C-Telopeptide Cross-linking of Tendon Type I Collagen in Fibromodulin-deficient Mice.
- 2014
-
Ingår i: Journal of Biological Chemistry. - 1083-351X .- 0021-9258. ; 289:27, s. 18873-18879
-
Tidskriftsartikel (refereegranskat)abstract
- The controlled assembly of collagen monomers into fibrils, with accompanying intermolecular cross-linking by lysyl oxidase-mediated bonds, is vital to the structural and mechanical integrity of connective tissues. This process is influenced by collagen-associated proteins, including Small Leucine-Rich Proteins (SLRPs), but the regulatory mechanisms are not well understood. Deficiency in fibromodulin, an SLRP, causes abnormal collagen fibril ultrastructure and decreased mechanical strength in mouse tendons. In this study, fibromodulin deficiency rendered tendon collagen more resistant to non-proteolytic extraction. The collagen had an increased and altered cross-linking pattern at an early stage of fibril formation. Collagen extracts contained a higher proportion of stably cross-linked α1(I) chains as a result of their C-telopeptide lysines being more completely oxidized to aldehydes. The findings suggest that fibromodulin selectively affects the extent and pattern of lysyl oxidase-mediated collagen cross-linking by sterically hindering access of the enzyme to telopeptides, presumably through binding to the collagen. Such activity implies a broader role for SLRP family members in regulating collagen cross-linking placement and quantity.
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| 25. |
- Kalamajski, Sebastian, et al.
(författare)
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The decorin sequence SYIRIADTNIT binds collagen type I.
- 2007
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 282:22, s. 16062-16067
-
Tidskriftsartikel (refereegranskat)abstract
- Decorin belongs to the small leucine-rich repeat proteoglycan family, interacts with fibrillar collagens, and regulates the assembly, structure, and biomechanical properties of connective tissues. The decorin-collagen type I-binding region is located in leucine-rich repeats 5–6. Site-directed mutagenesis of this 54-residue-long collagen-binding sequence identifies Arg-207 and Asp-210 in leucine-rich repeat 6 as crucial for the binding to collagen. The synthetic peptide SYIRIADTNIT, which includes Arg-207 and Asp-210, inhibits the binding of full-length recombinant decorin to collagen in vitro. These collagen-binding amino acids are exposed on the exterior of the beta-sheet-loop structure of the leucine-rich repeat. This resembles the location of interacting residues in other leucine-rich repeat proteins.
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| 26. |
- Kalamajski, Sebastian, et al.
(författare)
-
The role of small leucine-rich proteoglycans in collagen fibrillogenesis.
- 2010
-
Ingår i: Matrix Biology. - : Elsevier BV. - 1569-1802 .- 0945-053X. ; 29, s. 248-253
-
Tidskriftsartikel (refereegranskat)abstract
- Small leucine-rich proteoglycans/proteins (SLRPs) are associated with collagen fibril formation, and therefore important for the proper formation of extracellular matrices. SLRPs are differentially expressed in tissues and during pathological conditions, contributing to the development of connective tissue properties. The binding of SLRPs to collagens have recently been characterized, and may give some clues to the significance of these interactions. In this mini review, we summarize published work in this field, and propose several mechanisms for how SLRPs can control collagen matrix structure and function. SLRPs appear to influence collagen cross-linking patterns. We also propose that the SLRP-collagen interactions can assist in the process of juxtaposing the collagen monomers by steric hindrance or by directly connecting two collagen monomers during the fibril growth.
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| 27. |
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| 28. |
- Lidén, Åsa, et al.
(författare)
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A fibronectin-binding protein from Streptococcus equi binds collagen and modulates cell-mediated collagen gel contraction
- 2006
-
Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 340:2, s. 604-610
-
Tidskriftsartikel (refereegranskat)abstract
- The N-terminal fragment (FNZN) of the fibronectin-binding protein FNZ from Streptococcus equi subspecies zooepidemicus was investigated as to effects on murine cell interactions with extracellular matrix proteins. FNZN bound to immobilized fibronectin (FN) and native, but not denatured, collagen type I. FNZN had no effect on primary adhesion of cells from the murine myoblastic C2C12 cell line to immobilized fibronectin. C2C12 cells adhered to immobilized FNZN, a process that was not inhibited by anti-human FN IgG or by an inhibitor of integrin alphaVbeta3. C2C12 cells lack collagen-binding beta1 integrins and neither adhere to native collagen nor mediate contraction of three-dimensional collagen gels. FNZN stimulated collagen gel contraction by C2C12 cells but not adhesion of C2C12 cells to collagen. Experiments with an alphaVbeta3-inhibitor suggested that FNZN promoted contraction by a process requiring alphaVbeta3. Our data suggest that FNZN by binding to cells, collagen, and FN modulate complex adhesive processes mediated by the alphaVbeta3 integrin. Since alphaVbeta3-mediated contractile events function to counteract edema formation during inflammation, it is possible that FNZN and its secreted homologue FNE modulate edema responses in infected tissues.
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| 29. |
- Maccarana, Marco, et al.
(författare)
-
Asporin-deficient mice have tougher skin and altered skin glycosaminoglycan content and structure
- 2017
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:8
-
Tidskriftsartikel (refereegranskat)abstract
- The main structural component of connective tissues is fibrillar, cross-linked collagen whose fibrillogenesis can be modulated by Small Leucine-Rich Proteins/Proteoglycans (SLRPs). Not all SLRPs’ effects on collagen and extracellular matrix in vivo have been elucidated; one of the less investigated SLRPs is asporin. Here we describe the successful generation of an Aspn-/- mouse model and the investigation of the Aspn-/- skin phenotype. Functionally, Aspn-/- mice had an increased skin mechanical toughness, although there were no structural changes present on histology or immunohistochemistry. Electron microscopy analyses showed 7% thinner collagen fibrils in Aspn-/- mice (not statistically significant). Several matrix genes were upregulated, including collagens (Col1a1, Col1a2, Col3a1), matrix metalloproteinases (Mmp2, Mmp3) and lysyl oxidases (Lox, Loxl2), while lysyl hydroxylase (Plod2) was downregulated. Intriguingly no differences were observed in collagen protein content or in collagen cross-linking-related lysine oxidation or hydroxylation. The glycosaminoglycan content and structure in Aspn-/- skin was profoundly altered: chondroitin/dermatan sulfate was more than doubled and had an altered composition, while heparan sulfate was halved and had a decreased sulfation. Also, decorin and biglycan were doubled in Aspn-/- skin. Overall, asporin deficiency changes skin glycosaminoglycan composition, and decorin and biglycan content, which may explain the changes in skin mechanical properties.
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| 30. |
- Maccarana, Marco, et al.
(författare)
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Dermatan Sulfate Epimerase 1-Deficient Mice have Reduced Content and Changed Distribution of Iduronic acids in Dermatan Sulfate and an Altered Collagen Structure in Skin.
- 2009
-
Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 29, s. 5517-5528
-
Tidskriftsartikel (refereegranskat)abstract
- Dermatan sulfate epimerase 1 (DS-epi1) and 2 convert glucuronic acid to iduronic acid in chondroitin/dermatan sulfate biosynthesis. Here we report on the generation of DS-epi1-null mice and the resulting alterations in the chondroitin/dermatan polysaccharide chains. The numbers of long blocks of adjacent iduronic acids are greatly decreased in skin decorin and biglycan chondroitin/dermatan sulfate, along with a parallel decrease of iduronic-2-O-sulfated-galactosamine-4-O-sulfated structures. Both iduronic acid blocks and iduronic acids surrounded by glucuronic acids are also decreased in versican-derived chains. DS-epi1-deficient mice are smaller than wild-type littermates, but otherwise have no gross macroscopic alterations. The lack of DS-epi1 affects the chondroitin/dermatan sulfate in many proteoglycans and the consequences for skin collagen structure were initially analyzed. We found that the skin collagen architecture was altered, and electron microscopy showed that the DS-epi1-null fibrils have a larger diameter than the wild-type fibrils. The altered chondroitin/dermatan sulfate chains carried by decorin in skin are likely to affect the collagen fibril formation and reduce the tensile strength of DS-epi1-null skin.
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| 31. |
- Oldberg, Åke, et al.
(författare)
-
Collagen-binding proteoglycan fibromodulin can determine stroma matrix structure and fluid balance in experimental carcinoma.
- 2007
-
Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 104:35, s. 13966-13971
-
Tidskriftsartikel (refereegranskat)abstract
- Research on the biology of the tumor stroma has the potential to lead to development of more effective treatment regimes enhancing the efficacy of drug-based treatment of solid malignancies. Tumor stroma is characterized by distorted blood vessels and activated connective tissue cells producing a collagen-rich matrix, which is accompanied by elevated interstitial fluid pressure (IFP), indicating a transport barrier between tumor tissue and blood. Here, we show that the collagen-binding proteoglycan fibromodulin controls stroma structure and fluid balance in experimental carcinoma. Gene ablation or inhibition of expression by anti-inflammatory agents showed that fibromodulin promoted the formation of a dense stroma and an elevated IFP. Fibromodulin-deficiency did not affect vasculature but increased the extracellular fluid volume and lowered IFP. Our data suggest that fibromodulin controls stroma matrix structure that in turn modulates fluid convection inside and out of the stroma. This finding is particularly important in relation to the demonstration that targeted modulations of the fluid balance in carcinoma can increase the response to cancer therapeutic agents.
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| 32. |
- Olof Olsson, P., et al.
(författare)
-
Inhibition of integrin αvβ6 changes fibril thickness of stromal collagen in experimental carcinomas
- 2018
-
Ingår i: Cell Communication and Signaling. - : Springer Science and Business Media LLC. - 1478-811X. ; 16:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Chemotherapeutic efficacy can be improved by targeting the structure and function of the extracellular matrix (ECM) in the carcinomal stroma. This can be accomplished by e.g. inhibiting TGF-β1 and -β3 or treating with Imatinib, which results in scarcer collagen fibril structure in xenografted human KAT-4/HT29 (KAT-4) colon adenocarcinoma. Methods: The potential role of αVβ6 integrin-mediated activation of latent TGF-β was studied in cultured KAT-4 and Capan-2 human ductal pancreatic carcinoma cells as well as in xenograft carcinoma generated by these cells. The monoclonal αVβ6 integrin-specific monoclonal antibody 3G9 was used to inhibit the αVβ6 integrin activity. Results: Both KAT-4 and Capan-2 cells expressed the αVβ6 integrin but only KAT-4 cells could utilize this integrin to activate latent TGF-β in vitro. Only when Capan-2 cells were co-cultured with human F99 fibroblasts was the integrin activation mechanism triggered, suggesting a more complex, fibroblast-dependent, activation pathway. In nude mice, a 10-day treatment with 3G9 reduced collagen fibril thickness and interstitial fluid pressure in KAT-4 but not in the more desmoplastic Capan-2 tumors that, to achieve a similar effect, required a prolonged 3G9 treatment. In contrast, a 10-day direct inhibition of TGF-β1 and -β3 reduced collagen fibril thickness in both tumor models. Conclusion: Our data demonstrate that the αVβ6-directed activation of latent TGF-β plays a pivotal role in modulating the stromal collagen network in carcinoma, but that the sensitivity to αVβ6 inhibition depends on the simultaneous presence of alternative paths for latent TGF-β activation and the extent of desmoplasia.
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| 33. |
- Olsson, Olof, et al.
(författare)
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The Tyrosine Kinase Inhibitor Imatinib Augments Extracellular Fluid Exchange and Reduces Average Collagen Fibril Diameter in Experimental Carcinoma
- 2016
-
Ingår i: Molecular Cancer Therapeutics. - 1535-7163 .- 1538-8514. ; 15:10, s. 2455-2464
-
Tidskriftsartikel (refereegranskat)abstract
- A typical obstacle to cancer therapy is the limited distribution of low molecular weight anticancer drugs within the carcinoma tissue. In experimental carcinoma, imatinib (STI571) increases efficacy of synchronized chemotherapy, reduces tumor interstitial fluid pressure, and increases interstitial fluid volume. STI571 also increases the water-perfusable fraction in metastases from human colorectal adenocarcinomas. Because the mechanism(s) behind these effects have not been fully elucidated, we investigated the hypothesis that STI571 alters specific properties of the stromal extracellular matrix. We analyzed STI571-treated human colorectal KAT-4/HT-29 experimental carcinomas, known to have a well-developed stromal compartment, for solute exchange and glycosaminoglycan content, as well as collagen content, structure, and synthesis. MRI of STI571-treated KAT-4/HT-29 experimental carcinomas showed a significantly increased efficacy in dynamic exchanges of solutes between tumor interstitium and blood. This effect was paralleled by a distinct change of the stromal collagen network architecture, manifested by a decreased average collagen fibril diameter, and increased collagen turnover. The glycosaminoglycan content was unchanged. Furthermore, the apparent effects on the stromal cellular composition were limited to a reduction in an NG2-positive stromal cell population. The current data support the hypothesis that the collagen network architecture influences the dynamic exchanges of solutes between blood and carcinoma tissue. It is conceivable that STI571 reprograms distinct nonvascular stromal cells to produce a looser extracellular matrix, ultimately improving transport characteristics for traditional chemotherapeutic agents.
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| 34. |
- Olsson, P. Olof, et al.
(författare)
-
Fibromodulin deficiency reduces collagen structural network but not glycosaminoglycan content in a syngeneic model of colon carcinoma.
- 2017
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:8
-
Tidskriftsartikel (refereegranskat)abstract
- Tumor barrier function in carcinoma represents a major challenge to treatment and is therefore an attractive target for increasing drug delivery. Variables related to tumor barrier include aberrant blood vessels, high interstitial fluid pressure, and the composition and structure of the extracellular matrix. One of the proteins associated with dense extracellular matrices is fibromodulin, a collagen fibrillogenesis modulator expressed in tumor stroma but scarce in normal loose connective tissues. Here, we investigated the effects of fibromodulin on stroma ECM in a syngeneic murine colon carcinoma model. We show that fibromodulin deficiency decreased collagen fibril thickness but glycosaminoglycan content and composition were unchanged. Furthermore, vascular density, pericyte coverage and macrophage amount were unaffected. Fibromodulin can therefore be a unique effector of dense collagen matrix assembly in tumor stroma and, without affecting other major matrix components or the cellular composition, can function as a main agent in tumor barrier function.
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| 35. |
- Olsson, P. Olof, et al.
(författare)
-
Inhibition of integrin alpha(V)beta(6) changes fibril thickness of stromal collagen in experimental carcinomas
- 2018
-
Ingår i: Cell Communication and Signaling. - : BMC. - 1478-811X. ; 16
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Chemotherapeutic efficacy can be improved by targeting the structure and function of the extracellular matrix (ECM) in the carcinomal stroma. This can be accomplished by e.g. inhibiting TGF beta 1 and -beta 3 or treating with Imatinib, which results in scarcer collagen fibril structure in xenografted human KAT-4/HT29 (KAT-4) colon adenocarcinoma.Methods: The potential role of a(v)beta(6) integrin-mediated activation of latent TGF-beta was studied in cultured KAT-4 and Capan-2 human ductal pancreatic carcinoma cells as well as in xenograft carcinoma generated by these cells. The monoclonal a(v)beta(6) integrin-speafic monoclonal antibody 3G9 was used to inhibit the a(v)beta(6) integrin activity.Results: Both KAT-4 and Capan-2 cells expressed the a(v)beta(6) integrin but only KAT-4 cells could utilize this integrin to activate latent TGF-beta in vitro. Only when Capan-2 cells were co-cultured with human F99 fibroblasts was the integrin activation mechanism triggered, suggesting a more complex, fibroblast-dependent, activation pathway. In nude mice, a 10-day treatment with 3G9 reduced collagen fibril thickness and interstitial fluid pressure in KAT-4 but not in the more desmoplastic Capan-2 tumors that, to achieve a similar effect, required a prolonged 3G9 treatment. In contrast, a 10-day direct inhibition of TGF-beta 1 and -beta 3 reduced collagen fibril thickness in both tumor models.Conclusion: Our data demonstrate that the a(v)beta(6)-directed activation of latent TGF-beta plays a pivotal role in modulating the stromal collagen network in carcinoma, but that the sensitivity to a(v)beta(6) inhibition depends on the simultaneous presence of alternative paths for latent TGF-beta activation and the extent of desmoplasia.
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| 36. |
- Paracuellos, Patricia, et al.
(författare)
-
Structural and functional analysis of two small leucine-rich repeat proteoglycans, fibromodulin and chondroadherin
- 2017
-
Ingår i: Matrix Biology. - : Elsevier BV. - 0945-053X .- 1569-1802. ; 63, s. 106-116
-
Tidskriftsartikel (refereegranskat)abstract
- The small leucine-rich proteoglycans (SLRPs) are important regulators of extracellular matrix assembly and cell signalling. We have determined crystal structures at ~2.2Å resolution of human fibromodulin and chondroadherin, two collagen-binding SLRPs. Their overall fold is similar to that of the prototypical SLRP, decorin, but unlike decorin neither fibromodulin nor chondroadherin forms a stable dimer. A previously identified binding site for integrin α2β1 maps to an α-helix in the C-terminal cap region of chondroadherin. Interrogation of the Collagen Toolkits revealed a unique binding site for chondroadherin in collagen II, and no binding to collagen III. A triple-helical peptide containing the sequence GAOGPSGFQGLOGPOGPO (O is hydroxyproline) forms a stable complex with chondroadherin in solution. In fibrillar collagen I and II, this sequence is aligned with the collagen cross-linking site KGHR, suggesting a role for chondroadherin in cross-linking.
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| 37. |
- Shami, Annelie, et al.
(författare)
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Fibromodulin Deficiency Reduces Low-Density Lipoprotein Accumulation in Atherosclerotic Plaques in Apolipoprotein E-Null Mice.
- 2012
-
Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1524-4636.
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to analyze how an altered collagen structure affects development of atherosclerotic plaques. METHODS AND RESULTS: Fibromodulin-null mice develop an abnormal collagen fibril structure. In apolipoprotein E (ApoE)-null and ApoE/fibromodulin-null mice, a shear stress-modifying carotid artery cast induced formation of atherosclerotic plaques of different phenotypes; inflammatory in low-shear stress regions and fibrous in oscillatory shear stress regions. Electron microscopy showed that collagen fibrils were thicker and more heterogeneous in oscillatory shear stress lesions from ApoE/fibromodulin-null mice. Low-shear stress lesions were smaller in ApoE/fibromodulin-null mice and contained less lipids. Total plaque burden in aortas stained en face with Oil Red O, as well as lipid accumulation in aortic root lesions, was also decreased in ApoE/fibromodulin-null mice. In addition, lipid accumulation in RAW264.7 macrophages cultured on fibromodulin-deficient extracellular matrix was decreased, whereas levels of interleukin-6 and -10 were increased. Our results show that an abnormal plaque collagen fibril structure can influence atherosclerotic plaque development. CONCLUSIONS: The present findings suggest a more complex role for collagen in plaque stability than previously anticipated, in that it may promote lipid-accumulation and inflammation at the same time as it provides mechanical stability.
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| 38. |
- Soderberg, Marie Westergren, et al.
(författare)
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Gene expressions of small leucine-rich repeat proteoglycans and fibulin-5 are decreased in pelvic organ prolapse
- 2009
-
Ingår i: Molecular Human Reproduction. - : Oxford University Press (OUP). - 1460-2407 .- 1360-9947. ; 15:4, s. 251-257
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Tidskriftsartikel (refereegranskat)abstract
- Few studies are performed on the sustainability of the pelvic floor extracellular matrix important for preventing development of pelvic organ prolapse (POP). Collagens I and III, the elastin-associated proteins fibrillin-1 and fibulin-5 and the small leucine-rich repeat proteoglycans (SLRPs) decorin, lumican and fibromodulin are involved in giving the tissue its mechanical properties. Para-urethral biopsies were obtained from 15 women, 6 pre- and 9 post-menopausal, with POP. Real-time reverse transcription-polymerase chain reaction and immunohistochemistry for collagen I, collagen III, fibrillin-1, fibulin-5, decorin, lumican and fibromodulin were performed and compared with 14 controls, 8 pre- and 6 post-menopausal. Statistical comparisons controlled for age changes in gene expressions. A 16-fold decrease in decorin mRNA expression, P = 0.0001, and 8-fold in lumican mRNA expression, P = 0.001, were discovered in premenopausal POP compared with matched controls. In all women with POP, there were lower gene expressions of fibromodulin, P = 0.004, and fibulin-5, P = 0.001, compared with all controls. All proteins were detectable by immunohistochemistry, showing a weaker staining for decorin in premenopausal POP. For the first time, we show substantially decreased gene signal for production of SLRPs, regulators of collagen fiber assembly and impairment in elastic fiber assembly by down-regulation of fibulin-5 in POP.
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| 39. |
- Ström, Kristoffer, et al.
(författare)
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Genetic variation at RAB3GAP2 and its role in exercise-related adaptation and recovery
- 2021
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Skeletal muscle fiber composition and capillary density influence physical performance and whole-body metabolic properties. ~45% of the variance in fiber type is heritable, which motivated us to perform a genome-wide association study of skeletal muscle histology from 656 Swedish men. Four independent variants were associated (p
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| 40. |
- Tillgren, Viveka, et al.
(författare)
-
Novel Small Leucine-Rich Protein Chondroadherin-like (CHADL) is Expressed in Cartilage and Modulates Chondrocyte Differentiation.
- 2015
-
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 290:2, s. 918-925
-
Tidskriftsartikel (refereegranskat)abstract
- The constitution and biophysical properties of extracellular matrices can dramatically influence cellular phenotype during development, homeostasis, or pathogenesis. These effects can be signaled through a differentially regulated assembly of collagen fibrils, orchestrated by a family of collagen-associated Small Leucine-Rich Proteins, SLRPs. In this report, we describe the tissue-specific expression and function of a previously uncharacterized SLRP Chondroadherin-like (CHADL). We have developed antibodies against CHADL and, by immunohistochemistry, detected CHADL expression mainly in skeletal tissues, particularly in fetal cartilage and in pericellular space of adult chondrocytes. In situ hybridizations and immunoblots on tissue lysates confirmed this tissue-specific expression pattern. Recombinant CHADL bound collagen in cell culture, and inhibited in vitro collagen fibrillogenesis. After Chadl shRNA knockdown chondrogenic ATDC5 cells increased their proliferation and differentiation, indicated by increased transcript levels of Sox9, Ihh, Col2a1, and Col10a1. The knockdown increased collagen II and aggrecan deposition in the cell layers. Microarray analysis of the knockdown samples suggested collagen receptor-related changes, although other upstream effects could not be excluded. Together, our data indicate that the novel SLRP CHADL is expressed in cartilaginous tissues, influences collagen fibrillogenesis, and modulates chondrocyte proliferation and differentiation. CHADL appears to have a negative regulatory role, possibly ensuring the formation of a stable extracellular matrix.
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| 41. |
- Tillgren, Viveka, et al.
(författare)
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The Tyrosine Sulfate Domain of Fibromodulin Binds Collagen and Enhances Fibril Formation
- 2016
-
Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 291:45, s. 23744-23755
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Tidskriftsartikel (refereegranskat)abstract
- Small leucine-rich proteoglycans interact with other extracellular matrix proteins and are important regulators of matrix assembly. Fibromodulin has a key role in connective tissues, binding collagen through two identified binding sites in its leucine-rich repeat domain and regulating collagen fibril formation in vitro and in vivo Some nine tyrosine residues in the fibromodulin N-terminal domain are O-sulfated, a posttranslational modification often involved in protein interactions. The N-terminal domain mimics heparin, binding proteins with clustered basic amino acid residues. Because heparin affects collagen fibril formation, we investigated whether tyrosine sulfate is involved in fibromodulin interactions with collagen. Using full-length fibromodulin and its N-terminal tyrosine-sulfated domain purified from tissue, as well as recombinant fibromodulin fragments, we found that the N-terminal domain binds collagen. The tyrosine-sulfated domain and the leucine-rich repeat domain both bound to three specific sites along the collagen type I molecule, at the N terminus and at 100 and 220 nm from the N terminus. The N-terminal domain shortened the collagen fibril formation lag phase and tyrosine sulfation was required for this effect. The isolated leucine-rich repeat domain inhibited the fibril formation rate, and full-length fibromodulin showed a combination of these effects. The fibrils formed in the presence of fibromodulin or its fragments showed more organized structure. Fibromodulin and its tyrosine sulfate domain remained bound on the formed fiber. Taken together, this suggests a novel, regulatory function for tyrosine sulfation in collagen interaction and control of fibril formation.
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| 42. |
- van Wieringen, Tijs, et al.
(författare)
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The streptococcal collagen-binding protein CNE specifically interferes with {alpha}V{beta}3-mediated cellular interactions with triple helical collagen
- 2010
-
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 285:46, s. 35803-35813
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Tidskriftsartikel (refereegranskat)abstract
- Collagen fibers expose distinct domains allowing for specific interactions with other extracellular matrix proteins and cells. To investigate putative collagen domains that govern integrin α(V)β(3)-mediated cellular interactions with native collagen fibers we took advantage of the streptococcal protein CNE that bound native fibrillar collagens. CNE specifically inhibited α(V)β(3)-dependent cell-mediated collagen gel contraction, PDGF BB-induced and α(V)β(3)-mediated adhesion of cells, and binding of fibronectin to native collagen. Using a Toolkit composed of overlapping, 27-residue triple helical segments of collagen type II, two CNE-binding sites present in peptides II-1 and II-44 were identified. These peptides lack the major binding site for collagen-binding β(1) integrins, defined by the peptide GFOGER. Peptide II-44 corresponds to a region of collagen known to bind collagenases, discoidin domain receptor 2, SPARC (osteonectin), and fibronectin. In addition to binding fibronectin, peptide II-44 but not II-1 inhibited α(V)β(3)-mediated collagen gel contraction and, when immobilized on plastic, supported adhesion of cells. Reduction of fibronectin expression by siRNA reduced PDGF BB-induced α(V)β(3)-mediated contraction. Reconstitution of collagen types I and II gels in the presence of CNE reduced collagen fibril diameters and fibril melting temperatures. Our data indicate that contraction proceeded through an indirect mechanism involving binding of cell-produced fibronectin to the collagen fibers. Furthermore, our data show that cell-mediated collagen gel contraction does not directly depend on the process of fibril formation.
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