Contributions
Abstract: P454
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 15 Immunology
Pathogenic T helper (TH)17 cells play a major role in multiple sclerosis (MS). Cytokines expressed by these cells, IL-17 and IL-22, have been shown to compromise the blood-brain-barrier (BBB). BBB disruption is an important early event in MS, which allows recruitment and migration of peripheral immune cells into the central nervous system. IL-26 is a TH17 cell associated cytokine, which signals through its heterodimeric receptor, IL-10R2 and IL-20R1. Therefore, it might be involved in BBB functionality and have implications for MS.
Objectives: To investigate the presence of IL-26 in MS patients and to assess the effect of IL-26 on the integrity of the BBB.
Methods: QPCR and western blot were used to detect IL-26 in TH1, TH2, TH17 differentiated cells and IL-26 receptor (IL-26R) in human primary BBB endothelial cell (HBEC) cultures. Also, immunohistochemical staining (IHC) for IL-26/CD4 and IL-26R was performed on brain tissue from MS patients and controls. Next, the effect of dimeric recombinant human IL-26 (rhIL-26) on HBEC cultures was studied in vitro in permeability and transendothelial electrical resistance assays. The effect of IL-26 on BBB integrity was also studied in vivo, in a mouse model for neuroinflammation, experimental autoimmune encephalomyelitis (EAE). Therefore, 5 days after EAE induction, mice were daily injected with rhIL-26 or HBSS. At different time points, IgG and fibrinogen extravasation into the spinal cord was assessed by IHC. Moreover, clinical disease score was determined.
Results: Our results showed that IL-26 is mainly expressed by TH17 differentiated cells in HC and MS patients. Moreover, we found CD4+IL-26+ cells in perivascular infiltrates in MS brain tissue. Next, we showed that HBEC express the heterodimer IL-26R. This receptor was also found in MS brain tissue on endothelial cells. Treatment of an HBEC single cell layer with rhIL-26 showed a reduced permeability and an increased resistance. Finally, our in vivo data in mice with EAE showed that rhIL-26 treatment started before disease onset resulted in a reduced extravasation of IgG and fibrinogen into the spinal cord at peak of disease compared to HBSS treated mice. Moreover, there was a significant reduction in disease severity in the IL-26 treated group.
Conclusion: Although IL-26 is mainly a TH17 associated cytokine, it promotes BBB integrity in vitro and in vivo. Moreover, it reduces disease severity in EAE.
Disclosure: This project was funded by a grant from the Canadian Institutes of Health Research (CIHR) and Evelyn Peelen was awarded with a postdoctoral fellowship from the Fonds de recherche du Québec - Santé (FRQS) and the MS Society Canada for this project.
Regarding this project, all authors have nothing to disclose.
Abstract: P454
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 15 Immunology
Pathogenic T helper (TH)17 cells play a major role in multiple sclerosis (MS). Cytokines expressed by these cells, IL-17 and IL-22, have been shown to compromise the blood-brain-barrier (BBB). BBB disruption is an important early event in MS, which allows recruitment and migration of peripheral immune cells into the central nervous system. IL-26 is a TH17 cell associated cytokine, which signals through its heterodimeric receptor, IL-10R2 and IL-20R1. Therefore, it might be involved in BBB functionality and have implications for MS.
Objectives: To investigate the presence of IL-26 in MS patients and to assess the effect of IL-26 on the integrity of the BBB.
Methods: QPCR and western blot were used to detect IL-26 in TH1, TH2, TH17 differentiated cells and IL-26 receptor (IL-26R) in human primary BBB endothelial cell (HBEC) cultures. Also, immunohistochemical staining (IHC) for IL-26/CD4 and IL-26R was performed on brain tissue from MS patients and controls. Next, the effect of dimeric recombinant human IL-26 (rhIL-26) on HBEC cultures was studied in vitro in permeability and transendothelial electrical resistance assays. The effect of IL-26 on BBB integrity was also studied in vivo, in a mouse model for neuroinflammation, experimental autoimmune encephalomyelitis (EAE). Therefore, 5 days after EAE induction, mice were daily injected with rhIL-26 or HBSS. At different time points, IgG and fibrinogen extravasation into the spinal cord was assessed by IHC. Moreover, clinical disease score was determined.
Results: Our results showed that IL-26 is mainly expressed by TH17 differentiated cells in HC and MS patients. Moreover, we found CD4+IL-26+ cells in perivascular infiltrates in MS brain tissue. Next, we showed that HBEC express the heterodimer IL-26R. This receptor was also found in MS brain tissue on endothelial cells. Treatment of an HBEC single cell layer with rhIL-26 showed a reduced permeability and an increased resistance. Finally, our in vivo data in mice with EAE showed that rhIL-26 treatment started before disease onset resulted in a reduced extravasation of IgG and fibrinogen into the spinal cord at peak of disease compared to HBSS treated mice. Moreover, there was a significant reduction in disease severity in the IL-26 treated group.
Conclusion: Although IL-26 is mainly a TH17 associated cytokine, it promotes BBB integrity in vitro and in vivo. Moreover, it reduces disease severity in EAE.
Disclosure: This project was funded by a grant from the Canadian Institutes of Health Research (CIHR) and Evelyn Peelen was awarded with a postdoctoral fellowship from the Fonds de recherche du Québec - Santé (FRQS) and the MS Society Canada for this project.
Regarding this project, all authors have nothing to disclose.