A large-scale functional analysis of genes expressed differentially in insulin secreting MIN6 sublines with high versus mildly reduced glucose-responsiveness

by Selleckchem | May 01 2023

Molecular mechanisms of glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells are not fully understood. GSIS deteriorations are believed to underlie the pathogenesis of type 2 diabetes mellitus. By comparing transcript levels of 3 insulin secreting MIN6 cell sublines with strong glucose-responsiveness and 3 with mildly reduced responsiveness, we identified 630 differentially expressed genes. Using our recently developed system based on recombinase-mediated cassette exchange, we conducted large-scale generation of stable clones overexpressing such genes in the doxycycline-regulated manner. We found that overexpressions of 18, out of 83, genes altered GSIS. Sox11 ((sex determining region Y)-box 11) was selected to confirm its roles in regulating insulin secretion, and the gene was subjected to shRNA-mediated suppression. While Sox11 overexpression decreased GSIS, its suppression increased GSIS, confirming the role of Sox11 as a negative regulator of insulin secretion. Furthermore, metabolic experiments using radiolabelled glucose showed Sox11 to participate in regulating glucose metabolism. Our data suggested that overexpression screening is a feasible option for systemic functional testing to identify important genes in GSIS.

Comments：

The molecular mechanisms underlying glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells are complex and not fully understood. However, GSIS defects are known to contribute to the development of type 2 diabetes mellitus. In this study, the authors aimed to identify genes that play a role in GSIS by comparing the transcript levels of insulin-secreting MIN6 cell sublines with varying degrees of glucose-responsiveness.

The authors identified 630 differentially expressed genes between the highly glucose-responsive MIN6 cell sublines and those with mildly reduced responsiveness. They then used a system based on recombinase-mediated cassette exchange to generate stable clones that overexpressed these genes in a doxycycline-regulated manner. By screening these clones, they identified 18 genes that altered GSIS.

One of the identified genes, Sox11, was selected for further study to confirm its role in regulating insulin secretion. The authors used shRNA-mediated suppression to decrease Sox11 expression and found that this increased GSIS. Conversely, overexpression of Sox11 decreased GSIS, confirming its role as a negative regulator of insulin secretion. Additionally, metabolic experiments using radiolabelled glucose showed that Sox11 is involved in regulating glucose metabolism.

Overall, this study demonstrates that a large-scale screening approach based on overexpression is a feasible option for identifying genes involved in GSIS. The identification of Sox11 as a negative regulator of insulin secretion and its role in glucose metabolism provide insights into the molecular mechanisms underlying GSIS and may have implications for the development of new therapies for type 2 diabetes mellitus.