MicroRNA-7 regulates the mTOR pathway and proliferation in adult pancreatic b-cells

Abstract

Elucidating the mechanism underlying the poor proliferative capacity of adult pancreatic b-cells is critical to regenerative therapeutic approaches for diabetes. Here, we show that the micro- RNA (miR)-7/7ab family member miR-7a is enriched in mouse adult pancreatic islets compared with miR-7b. Remarkably, miR- 7a targets five components of the mTOR signaling pathway. Further, inhibition of miR-7a activates mTOR signaling and promotes adult b-cell replication in mouse primary islets, which can be reversed by the treatment with a well-known mTOR inhibitor, rapamycin. These data suggest that miR-7 acts as a brake on adult b-cell proliferation. Most importantly, this miR-7-mTOR proliferation axis is conserved in primary human b-cells, implicating miR-7 as a therapeutic target for diabetes. Copyright © 2013 by the American Diabetes Association.