RNAsequencing of control and STAT3 knocked down transriptomes of EndoC cells

Most obese and insulin resistant individuals do not develop diabetes. This is the result of the capacity of β-cells to adapt and produce enough insulin to cover the needs of the organism. The underlying mechanism of β-cell adaptation in obesity, however, remains unclear. Previous studies have suggested a role for STAT3 in mediating β-cell development and human glucose homeostasis, but little is known about its role in β-cells in obesity. We observed enhanced cytoplasmatic expression of STAT3 in severe obese and diabetic subjects. To address the functional role of STAT3 in adult β-cells, we generated mice with tamoxifen-inducible partial or full deletion of STAT3 in β-cells and fed them a high fat diet before analysis. Interestingly, β-cell homozygous and heterozygous STAT3 deficient obese mice showed glucose intolerance when compared to controls. Gene expression analysis by RNA-seq showed reduced expression of mitochondrial genes in STAT3 knocked-down human EndoC-βH1 cells and was confirmed in FACS-purified β-cells from STAT3 deficient mice. Moreover, knockdown of STAT3 impaired mitochondria activity in EndoC-βH1 and human islets, suggesting a mechanism for STAT3-regulated β-cell function. We propose non-canonical STAT3 activity as a marker of β-cell identity, improving glucose induced insulin secretion in obesity. mRNA profiles of control and STAT3 knocked-down β-cells