Repression of lung tumor suppressor gene G protein-coupled receptor class C group 5 member A expression by inflammatory signal pathway / 上海交通大学学报（医学版）

ABSTRACT

Objective · To investigate the regulatory effects of inflammatory signaling pathway on the expression of G protein-coupled receptor class C group 5 member A (GPRC5A).Methods· Nuclear factor κB (NF-κB)-driven luciferase mice were intraperitoneally injected with lipopolysaccharide (LPS) to evaluate the activation of NF-κB in lungs.GPRC5A expression in lungs was assessed by Western blotting in the C57BL/6J mice injected with LPS.In vitro tests,human lung tumor cell lines Calu-1 and H322,and human embryonic kidney cell line HEK293T were administered with tumor nccrosis factor α (TNF-α) or transfected with p65 expression plasmid;Western blotting,RT-PCR,luciferase reporter gene experiment and immunofluorescence assay were used to analyze the effect of inflammation on GPRC5A expression.Results · Intraperitoneal injection of LPS induced activation of NF-κB pathway in lung tissues,which suppressed the expression of GPRC5A in mice lungs.In Calu-1 cells,TNF-α treatment greatly suppressed the expression of GPRC5A protein and mRNA.In HEK293T cells,transfection of p65 subunit of NF-κB suppressed the expression of GPRC5A promoter-driven luciferase reporter.The H322 cells transfected with green fluorescent protein-p65 almost did not express GPRC5A.Conclusion · NF-κB pathway acts at the promoter of GPRC5A and suppresses its mRNA and protein expression.