High glucose promotes TGF-β1 production by inducing FOS expression in human peritoneal mesothelial cells.

BACKGROUND: High glucose (HG) induces production of transforming growth factor-beta1 (TGF-β1), but the mechanism remains elusive. The aim of this study was to determine the gene(s) involved in HG-induced TGF-β1 production in human peritoneal mesothelial cells (HPMCs).

METHODS: Microarray analysis was performed following a 3-h preincubation of HPMCs in 4 or 0.1% glucose medium. Transcriptional genes were selected using Gene Ontology analysis for biological processes, including regulation of transcription and DNA-dependent. The effects of small interfering RNA (siRNA) treatments on the up-regulation of TGF-β1 mRNA were assessed by quantitative real-time polymerase chain reaction (qPCR). Finally, enzyme-linked immunosorbent assay (ELISA) was performed to determine which gene(s) contribute to the production of TGF-β1 protein in the medium.

RESULTS: Microarray analysis revealed that the expression of 51 genes increased by more than 3-fold. Gene ontology analysis identified 13 genes for further study. qPCR confirmed mRNA amplification for 9 of the 13 genes. Furthermore, HG-induced up-regulation of TGF-β1 mRNA was attenuated by the siRNA of 4 genes: MDS1 and EVI1 complex locus (MECOM), FBJ murine osteosarcoma viral oncogene homolog B (FOSB), FBJ murine osteosarcoma viral oncogene homolog (FOS) and activating transcription factor 3 (ATF3). ELISA showed that siRNA treatment of FOS, but not MECOM, FOSB or ATF3, suppressed the increase of TGF-β1 protein in the medium.

CONCLUSIONS: FOS is a downstream effector of HG stimulation in HPMCs that contributes to TGF-β1 production, suggesting that blocking FOS expression may be a therapeutic target for peritoneal fibrosis.