Regulation of the Human IL-10RB Gene Expression by Sp8 and Sp9

Background: Interleukin-10 (IL-10) is a classic anti-inflammatory cytokine that exerts its effects via the receptor complexes IL-10RA and IL-10RB. Loss of IL-10RB results in many diseases. Moreover, IL-10RB is closely associated with neuronal survival and synaptic formation. However, the regulation of IL-10RB gene expression remains elusive. Objective: To investigate whether the expression of IL-10RB gene is increased in brain of Alzheimer’s disease (AD) and its transcriptional regulation. Methods: We examined the gene expression of AD patient brain from public database and detected the protein expression of AD model mouse brain by western blot. We constructed a variety of reporter gene plasmids with different lengths or mutation sites, tested the promoter activity and defined the functional region of the promoter with the luciferase reporter assay. The protein-DNA binding between transcription factors and the promoter was analyzed using chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA). Results: We found that the IL-10RB is elevated in the brain of AD patient and AD model mice. The minimal promoter of the IL-10RB gene is located in the –90 to +51 bp region (relative to the transcriptional start site) and is sufficient for high-level expression of the IL-10RB gene. Transcription factors Sp8 and Sp9 bind to the IL-10RB promoter in vitro. The overexpression or knockdown of Sp8 and Sp9 affected the IL-10RB promoter activity and its gene expression. Conclusion: Our study functionally characterized the promoter of the IL-10RB gene and demonstrated that Sp8 and Sp9 regulated its expression.