IADR Abstract Archives
Epigenetic influence in IRE1a/XBP-1 pathway in Sjögren’s syndrome patients.
Objectives: The IRE1/XBP-1 signaling pathway of the unfolded protein response involved in the regulation of the secretory process is dysregulated in labial salivary gland (LSG) from Sjögren’s syndrome patients (SS-patients). Previous results from our laboratory indicate a possible epigenetic influence, shown that this could be a consequence. To study the expression, promoter methylation status and localization of IRE1α/XBP-1 pathway components, and them in-vitro expression induced by inflammatory cytokines (IFN-g).
Methods: We studied LSGs belonging from 47 SS-patients and 37 control subjects. As experimental strategy, qPCR and western blot were used to evaluate the mRNA and protein levels of IRE1α, XBP1 and GRP78. The methylation status of promoters were analyzed by High resolution melting (HRM) 3D cultures of HSG cells were incubated with IFN-γ to evaluate the expression of the IRE1α/XBP-1 pathway components. Additionally, subcellular location of IRE1α, XBP1, and GRP78 were analyzed by immunofluorescence.
Results: A diminution of mRNA and protein levels of IRE1, XBP-1 and GRP78 were found in LSG from SS-patients.. These results are correlated with an increase in methylation levels of their promoters. Similar behavior was found in HSG cells incubated with IFN-γ
Conclusions: The decrease in mRNA levels of IRE1a, XBP-1, and GRP78 promoters could be a result of the hypermethylation of their respective promotors. Decreased expression of these components is consistent with chronic ER stress and could partly explain the glandular dysfunction observed in LSG of SS-patients. In HSG cells, local stress signals as pro-inflammatory cytokines modulate the expression of IRE1α/XBP-1 pathway components.
Methods: We studied LSGs belonging from 47 SS-patients and 37 control subjects. As experimental strategy, qPCR and western blot were used to evaluate the mRNA and protein levels of IRE1α, XBP1 and GRP78. The methylation status of promoters were analyzed by High resolution melting (HRM) 3D cultures of HSG cells were incubated with IFN-γ to evaluate the expression of the IRE1α/XBP-1 pathway components. Additionally, subcellular location of IRE1α, XBP1, and GRP78 were analyzed by immunofluorescence.
Results: A diminution of mRNA and protein levels of IRE1, XBP-1 and GRP78 were found in LSG from SS-patients.. These results are correlated with an increase in methylation levels of their promoters. Similar behavior was found in HSG cells incubated with IFN-γ
Conclusions: The decrease in mRNA levels of IRE1a, XBP-1, and GRP78 promoters could be a result of the hypermethylation of their respective promotors. Decreased expression of these components is consistent with chronic ER stress and could partly explain the glandular dysfunction observed in LSG of SS-patients. In HSG cells, local stress signals as pro-inflammatory cytokines modulate the expression of IRE1α/XBP-1 pathway components.