| 1. |
- Christerson, Ulrika, 1970-, et al.
(författare)
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Possible Involvement of Intracellular Calcium-Independent Phospholipase A(2) in the Release of Secretory Phospholipases from Mast Cells-Increased Expression in Ileal Mast Cells of Crohn's Disease
- 2019
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Ingår i: Cells. - : MDPI. - 2073-4409. ; 8:7, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Increased activity of secretory phospholipases A(2) (sPLA(2)) type-II was previously observed in ileum of Crohn's disease (CD). Our aims were to explore the involvement of calcium-independent (i)PLA(2 beta) in the release of sPLA(2)s from the human mast cell (MC) line (HMC-1) and investigate expressions of cytosolic (c)PLA(2) alpha, iPLA(2)beta, sPLA(2)-IIA and sPLA(2)-V in MCs of CD ileum. The release of sPLA(2) was investigated in HMC-1 by immunocytochemistry and ELISA. The expression intensities of PLA(2)s in mucosal MCs, and the proportion of PLA(2)-positive MCs, were investigated in normal ileum and in ileum from patients with CD by immunohistochemistry. The calcium ionophore-stimulated release of sPLA(2)-IIA and sPLA(2)-V from HMC-1 was reduced by the iPLA(2)-inhibitor bromoenol lactone. All four PLA(2)s were detectable in mucosal MCs, both in normal ileum and in CD, but the proportion of iPLA(2)beta-containing mucosal MCs and the expression intensity of sPLA(2)-IIA was increased in CD. Results indicate that iPLA(2)beta is involved in the secretion of sPLA(2)s from HMC-1, and suggest that iPLA(2)beta-mediated release of sPLA(2) from intestinal MCs may contribute to CD pathophysiology. Ex vivo studies on isolated mucosal mast cells are however needed to clarify the precise role of MC PLA(2)s in the inflammatory processes of CD.
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| 2. |
- Nordenfelt, Pontus, et al.
(författare)
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Different Requirements for Early and Late Phases of Azurophilic Granule-Phagosome Fusion
- 2009
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Ingår i: TRAFFIC. - : Wiley. - 1398-9219 .- 1600-0854. ; 10:12, s. 1881-1893
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Tidskriftsartikel (refereegranskat)abstract
- Phagocytosis and killing of microorganisms are complex processes that involve tightly regulated membrane traffic events. Because many signaling molecules associate with membrane rafts and because these structures can be found on azurophilic granules, we decided to investigate raft recruitment and the signaling requirements for azurophilic granule secretion during phagosome maturation. At the site of phagocytosis of immunoglobulin G-opsonized prey in human neutrophils, we found that early secretion of azurophilic granules was both raft- and calcium-dependent. Subsequently, rafts at the phagocytic site were internalized with the prey. At the fully formed phagosome, the fusion of azurophilic granules was no longer dependent on rafts or calcium. These findings were found to be true also when using Streptococcus pyogenes bacteria as prey, and depletion of calcium affected the kinetics of bacterial intracellular survival. These findings suggest that the mechanisms for delivery of azurophilic content to nascent and sealed phagosomes, respectively, differ in their dependence on calcium and membrane rafts.
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| 3. |
- Welin, Amanda, et al.
(författare)
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Incorporation of Mycobacterium tuberculosis lipoarabinomannan into macrophage membrane rafts is a prerequisite for the phagosomal maturation block.
- 2008
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Ingår i: Infection and Immunity. - Washington DC, USA : American society for microbiology. - 0019-9567 .- 1098-5522. ; 76:7, s. 2882-2887
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Tidskriftsartikel (refereegranskat)abstract
- Lipoarabinomannan (LAM) is one of the key virulence factors for Mycobacterium tuberculosis, the etiological agent of tuberculosis. During uptake of mycobacteria, LAM interacts with the cell membrane of the host macrophage and can be detected throughout the cell upon infection. LAM can inhibit phagosomal maturation as well as induce a proinflammatory response in bystander cells. The aim of this study was to investigate how LAM exerts its action on human macrophages. We show that LAM is incorporated into membrane rafts of the macrophage cell membrane via its glycosylphosphatidylinositol anchor and that incorporation of mannose-capped LAM from M. tuberculosis results in reduced phagosomal maturation. This is dependent on successful insertion of the glycosylphosphatidylinositol anchor. LAM does not, however, induce the phagosomal maturation block through activation of p38 mitogen-activated protein kinase, contradicting some previous suggestions.
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| 4. |
- Winberg Tinnerfelt, Martin, et al.
(författare)
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Leishmania donovani lipophosphoglycan inhibits phagosomal maturation via action on membrane rafts
- 2009
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Ingår i: Microbes and infection. - Paris, France : Elsevier BV. - 1286-4579 .- 1769-714X. ; 11:2, s. 215-222
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Tidskriftsartikel (refereegranskat)abstract
- Lipophosphoglycan (LPG), the major surface glycoconjugate on Leishmania donovani promastigotes, is crucial for the establishment of infection inside macrophages. LPG comprises a polymer of repeating Gal beta 1,4Man alpha-PO4 attached to a lysophosphatidylinositol membrane anchor. LPG is transferred from the parasite to the host macrophage membrane during phagocytosis and induces periphagosomal F-actin accumulation correlating with an inhibition of phagosomal maturation. The biophysical properties of LPG suggest that it may be intercalated into membrane rafts of the host-cell membrane. The aim of this study was to investigate if the effects of LPG on phagosomal maturation are mediated via action on membrane rafts. We show that LPG accumulates in rafts during phagocytosis of L. donovani and that disruption of membrane rafts abolished the effects of LPG on periphagosomal F-actin and phagosomal maturation, indicating that LPG requires intact membrane rafts to manipulate host-cell functions. We conclude that LPG associates with membrane rafts in the host cell and exert its actions on host-cell actin and phagosomal maturation through subversion of raft function.
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| 5. |
- Hagbom, Marie, et al.
(författare)
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Neurotrophic Factors Protect the Intestinal Barrier from Rotavirus Insult in Mice
- 2020
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Ingår i: mBio. - : AMER SOC MICROBIOLOGY. - 2161-2129 .- 2150-7511. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Increased intestinal permeability has been proposed as a mechanism of rotavirus-induced diarrhea. Studies with humans and mice have, however, shown that rotavirus leaves intestinal permeability unaffected or even reduced during diarrhea, in contrast to most bacterial infections. Gastrointestinal permeability is regulated by the vagus nerve and the enteric nervous system, which is composed of neurons and enteric glial cells (EGCs). We investigated whether the vagus nerve, serotonin (5-HT), EGCs, and neurotropic factors contribute to maintaining gut barrier homeostasis during rotavirus infection. Using subdiaphragmatic vagotomized and 5-HT3 receptor knockout mice, we found that the unaffected epithelial barrier during rotavirus infection is independent of the vagus nerve but dependent on 5-HT signaling through enteric intrinsic 5-HT3 receptors. Immunofluorescence analysis showed that rotavirus-infected enterocytes were in close contact with EGCs and enteric neurons and that the glial cell-derived neurotrophic factor (GDNF) was strongly upregulated in enterocytes of infected mice. Moreover, rotavirus and 5-HT activated EGCs (P < 0.001). Using Ussing chambers, we found that GDNF and S-nitrosoglutathione (GSNO) led to denser epithelial barriers in small intestinal resections from noninfected mice (P < 0.01) and humans (P < 0.001) and that permeability was unaffected in rotavirus-infected mice. GSNO made the epithelial barrier denser in Caco-2 cells by increasing the expression of the tight junction protein zona occludens 1 (P < 0.001), resulting in reduced passage of fluorescein isothiocyanate dextran (P < 0.05) in rotavirus-infected monolayers. This is the first report to show that neurotropic factors contribute to maintaining the gut epithelial barrier during viral insult. IMPORTANCE Human and mouse studies have shown that rotavirus infection is associated with low inflammation and unaffected intestinal barrier at the time of diarrhea, properties different from most bacterial and inflammatory diseases of the gut. We showed by in vitro, ex vivo, and in vivo experiments that neurotrophic factors and 5-HT have barrier protective properties during rotavirus insult. These observations advance our understanding of how the gut barrier is protected against rotavirus and suggest that rotavirus affects the gut barrier differently from bacteria. This is the first report to show that neurotrophic factors contribute to maintain the gut epithelial barrier during viral insult.
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| 6. |
- Alkaissi, Lina Y., et al.
(författare)
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Antagonism of Adherent Invasive E. coli LF82 With Human α-defensin 5 in the Follicle-associated Epithelium of Patients With Ileal Crohn’s Disease
- 2021
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Ingår i: Inflammatory Bowel Diseases. - : OXFORD UNIV PRESS INC. - 1078-0998 .- 1536-4844. ; 27:7, s. 1116-1127
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Tidskriftsartikel (refereegranskat)abstract
- Background: The first visible signs of Crohns disease (CD) are microscopic erosions over the follicle-associated epithelium (FAE). The aim of the study was to investigate the effects of human alpha-defensin 5 (HD5) on adherent-invasive Escherichia coli LF82 translocation and HD5 secretion after LF82 exposure in an in vitro model of human FAE and in human FAE ex vivo. Methods: An in vitro FAE-model was set up by the coculture of Raji B cells and Caco-2-cl1 cells. Ileal FAE from patients with CD and controls were mounted in Ussing chambers. The effect of HD5 on LF82 translocation was studied by LF82 exposure to the cells or tissues with or without incubation with HD5. The HD5 secretion was measured in human FAE exposed to LF82 or Salmonella typhimurium. The HD5 levels were evaluated by immunofluorescence, immunoblotting, and ELISA. Results: There was an increased LF82 translocation across the FAE-model compared with Caco-2-cl1 (P < 0.05). Incubation of cell/tissues with HD5 before LF82 exposure reduced bacterial passage in both models. Human FAE showed increased LF82 translocation in CD compared with controls and attenuated passage after incubation with sublethal HD5 in both CD and controls (P < 0.05). LF82 exposure resulted in a lower HD5 secretion in CD FAE compared with controls (P < 0.05), whereas Salmonella exposure caused equal secretion on CD and controls. There were significantly lower HD5 levels in CD tissues compared with controls. Conclusions: Sublethal HD5 reduces the ability of LF82 to translocate through FAE. The HD5 is secreted less in CD in response to LF82, despite a normal response to Salmonella. This further implicates the integrated role of antimicrobial factors and barrier function in CD pathogenesis.
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| 7. |
- Bednarska, Olga, et al.
(författare)
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A postbiotic fermented oat gruel may have a beneficial effect on the colonic mucosal barrier in patients with irritable bowel syndrome
- 2022
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Ingår i: Frontiers in Nutrition. - : FRONTIERS MEDIA SA. - 2296-861X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Impaired intestinal permeability and microbial dysbiosis are important pathophysiological mechanisms underlying irritable bowel syndrome (IBS). ReFerm (R)( ), also called Profermin (R), is a postbiotic product of oat gruel fermented with Lactobacillus plantarum 299v. In this study, we investigated whether ReFerm (R) has a beneficial effect on the intestinal epithelial barrier function in patients with IBS.Materials and methods: Thirty patients with moderate to severe IBS-diarrhoea (IBS-D) or IBS-mixed (IBS-M) were treated with enema containing ReFerm (R) or placebo. The patients underwent sigmoidoscopy with biopsies obtained from the distal colon at baseline and after 14 days of treatment with ReFerm (R) or placebo twice daily. The biopsies were mounted in Ussing chambers, and paracellular and transcellular permeabilities were measured for 120 min. In addition, the effects of ReFerm (R) or placebo on the epithelial barrier were investigated in vitro using Caco-2 cells.Results: ReFerm (R) reduced paracellular permeability (p < 0.05) and increased transepithelial resistance (TER) over time (p < 0.01), whereas the placebo had no significant effect in patients. In ReFerm (R)-treated Caco-2 cells, paracellular and transcellular permeabilities were decreased compared to the control (p < 0.05) and placebo (p < 0.01). TER was increased in Caco-2 ReFerm (R)-treated cells, and normalised TER was increased in ReFerm (R)-treated Caco-2 cells compared to control (p < 0.05) and placebo-treated (p < 0.05) cells.Conclusion: ReFerm (R) significantly reduced paracellular permeability and improved TER in colonic biopsies collected from patients with IBS and in a Caco-2 cell model. Our results offer new insights into the potential benefits of ReFerm (R) in IBS management. Further studies are needed to identify the molecular mechanisms underlying the barrier-protective properties of ReFerm (R).
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| 8. |
- Biskou, Olga, et al.
(författare)
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Increased Numbers of Enteric Glial Cells in the Peyers Patches and Enhanced Intestinal Permeability by Glial Cell Mediators in Patients with Ileal Crohns Disease
- 2022
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Ingår i: Cells. - Basel, Switzerland : MDPI. - 2073-4409. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Enteric glial cells (EGC) are known to regulate gastrointestinal functions; however, their role in Crohns disease (CD) is elusive. Microscopic erosions over the ileal Peyers patches are early signs of CD. The aim of this work was to assess the localization of EGC in the follicle and interfollicular region of the Peyers patches and in the lamina propria and study the effects of EGC mediators on barrier function in CD patients and non-inflammatory bowel disease (non-IBD) controls. EGC markers, glial fibrillary acidic protein (GFAP), and S100 calcium-binding protein β (S100β) were quantified by immunofluorescence and Western blotting. Both markers showed significantly more EGC in the Peyers patches and lamina propria of CD patients compared to the non-IBD controls. In CD patients there were significantly more EGC in Peyers patches compared to lamina propria, while the opposite pattern was seen in controls. Barrier function studies using Ussing chambers showed increased paracellular permeability by EGC mediators in CD patients, whereas permeability decreased by the mediators in controls. We show the accumulation of EGC in Peyers patches of CD patients. Moreover, EGC mediators induced barrier dysfunction in CD patients. Thus, EGC might have harmful impacts on ongoing inflammation and contribute to the pathophysiology of the disease.
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| 9. |
- Faisal, Mohammed, et al.
(författare)
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Effects of analgesic and surgical modality on immune response in colorectal cancer surgery
- 2021
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Ingår i: Surgial oncology. - : ELSEVIER SCI LTD. - 0960-7404 .- 1879-3320. ; 38
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective: Different surgical methods, anesthesia, and analgesia are known to modify the surgical stress response, especially in patients with malignancy. We compared the impact of patient-controlled intravenous (PCA) versus epidural analgesia (EDA) on tumor-related mucosal immune response in patients undergoing open or laparoscopic surgery for colorectal cancer. Methods: In a University Hospital subgroup (n = 43) of a larger cohort (n = 235) of patients undergoing open or laparoscopic surgery for colorectal carcinoma randomized to PCA or EDA, colorectal tissues were stained for interleukin-10 (IL-10), tumor necrosis factor (TNF), and mast cell tryptase and then examined by immunofluorescence microscopy. Results: More IL-10+-cells were found in patients undergoing open compared to laparoscopic surgery in the PCA (P < 0.05) and EDA group (P < 0.0005), respectively, and numbers of TNF+-cells were higher in the open surgery group who received PCA (P < 0.05). No differences in IL-10 or TNF expressions were detected between EDA/PCA within the open or laparoscopic surgery groups, respectively. Fewer mast cells were observed in patients undergoing laparoscopic compared to open surgery combined with PCA (P < 0.05). Within the open surgery group, EDA resulted in fewer mucosal mast cells compared to the PCA group (P < 0.05). Conclusions: The surgical method, rather than type of analgesia, may have higher impact on peri-operative inflammation. Laparoscopic surgery when combined with EDA for colorectal cancer caused a decrease in the TNF and IL-10 expression and mast cells. EDA seems to have an anti-inflammatory effect on cancer-related inflammation during open surgery.
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| 10. |
- Nordenfelt, Pontus, et al.
(författare)
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Phagosomal membrane rafts : azurophilic origin, Ca2+ dependence, and modulation by Streptococcus pyogenes bacteria
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Uptake and killing of microorganisms by neutrophils involve tightly regulated membrane traffic events that are governed by complex signals. Many of these are raft-associated, which implies that raft dynamics may be important during phagosome formation. Locally restricted, calcium-dependent, parallel upregulation of markers for membrane rafts and azurophilic granules was observed at the site of phagocytosis of IgG-opsonized prey in human neutrophils. Subsequent internalization of the prey reduced the levels of these markers in the plasma membrane. Streptococcus pyogenes bacteria, that can survive phagocytosis by neutrophils, modulated phagosomal raft acquisition by means of M proteins. Continued, but not early, delivery of rafts to the membrane of phagosomes in neutrophils and HL-60 cells was independent of calcium, as was fusion between azurophilic granules and phagosomes. Nevertheless, calcium depletion affected bacterial killing kinetics. These findings suggest that early delivery of membrane rafts is important for phagosomal maturation in neutrophils and provide new mechanistic insight into the processes required for generation of bactericidal phagosomes.
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