Signal transducer and activator of transcription 6 directly regulates human ORMDL3 expression

【摘要】：正Objective Orosomucoid-like 3(0RMDL3) has been associated with asthma and a series of autoimmune disorders and is involved in endoplasmic reticulum-mediated inflammatory responses.Yet,the clinical significance and molecular mechanism underlying its expression are still largely unclear.Methods To elucidate the mechanisms in human ORMDL3 transcriptional regulation,we cloned the 1.5-kb genomic DNA fragment containing the putative promoter region and evaluated its transcriptional activity in a luciferase reporter system by deletion analysis. EMSA,CMP,ChIP-Re-ChIP was used to identify the key transcription factors.Results We identified a 68-bp region that functions as a minimal promoter.Bioinformatics analysis predicted that the -64 to -56 bp region contained a signal transducer and activator of transcription 6(STAT6) binding site.Electrophoretic mobility shift assay and chromatin immunoprecipitation demonstrated that STAT6 bound to its binding site within the ORMDL3 promoter.STAT6 overexpression or knockdown could trans-activate or trans-inhibit,respectively,the ORMDL3 promoter containing the STAT6-binding motif.Interleukin 4(IL-4)/IL-13 treatment increased ORMDL3 promoter activity as Well as endogenous ORMDL3 expression.Immunoprecipitation and ChIP-Re-ChIP assays revealed that STAT6 and p300 exist in the same protein complex binding to the ORMDL3 promoter.Conclusions Our study confirmed that STAT6 plays important roles in regulating the expression of human ORMDL3 by directly binding to the promoter region, which can shed light on a possible role in various human diseases.