GSTO1 regulates insulin biosynthesis in pancreatic β cells.

Insulin biosynthesis and secretion by pancreatic β cells are critical for the maintenance of blood glucose homeostasis. Here, we show that the expression of glutathione S-transferase omega-1 (GSTO1) is upregulated in the primary islet cells of diabetic Goto-Kakizaki (GK) rats. Knocking out GSTO1 upregulated insulin transcripts and increased the insulin content in both INS-1 cells and primary islet cells. In contrast, overexpression of GSTO1 reduced the insulin content. Furthermore, knocking out GSTO1 increased the expression of pancreatic duodenal homeobox-1 (PDX1) at both the transcription and protein levels. These results indicate that GSTO1 may be involved in the regulation of insulin biosynthesis by modulating the transcriptional expression of PDX1. • GSTO1 expression was upregulated in the primary islet cells of diabetic Goto-Kakizaki (GK) rats. • Knocking out GSTO1 upregulated insulin transcription and increased the insulin content in pancreatic β cells. • Overexpression of GSTO1 reduced the insulin content in the INS-1 cells. • In the absence of GSTO1, PDX1 was upregulated at both the transcription and protein levels. [ABSTRACT FROM AUTHOR]