Involvement of Parkinson’s disease 7 in inflammatory bowel diseases: relation to interleukin-17 and tumor necrosis factor-alpha

Introduction: The therapy of inflammatory bowel diseases (IBD) is still unresolved, however, recent studies suggested the importance of interleukin (IL)-17. Parkinson's disease 7 (PARK7) is an antioxidant, immunoregulatory molecule, but its relation to IL-17 and the core TNF-α related pathway of IBD is completely unknown. Thus we aimed to investigate its involvement in the pathogenesis of IBD. Materials and methods: The mRNA expression, protein level and localization of PARK7 were determined in colon biopsies of children with IBD, in colon of wild type and Il17 KO mice with dextran sodium sulphate (DSS)-induced colitis and in IL-17-treated HT-29 colonic epithelial cells by real-time PCR, western blot, flow cytometry, and immunofluorescence staining, respectively. The effect of PARK7 on TNF-α was measured in PARK7 specific silencing RNA treated HT-29 cells. Results: Expression of PARK7 and IL-17 was elevated in the colonic mucosa of children with IBD and also in the colon of wild type mice with DSS-induced colitis compared to controls. Lack of IL-17 in Il17 KO mice prevented the DSS-induced elevation of colonic PARK7 level in vivo. Similarly, IL-17 treatment induced the production of PARK7 and TNF-α of HT-29 colon epithelial cells in vitro. TNF-α production were even more pronounced in the PARK7 siRNA treated HT-29 cells. Conclusion: Increased expression of PARK7 in IBD suggest its involvement in the disease pathogenesis. Moreover, we demonstrated that PARK-7 is an endogenous regulator of the IL-17 induced production of TNF-α. Taken together our data suggest that PARK7 may be a therapeutic target in the future. Grant support: Supported by UNKP-17-3 New National Excellence Program of the Ministry of Human Capacities, MTA-SE Pediatrics and Nephrology Research Group, Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences, OTKA K116928 and VKE-2017- 00006 grants.