Elucidating the mechanism underlying the poor proliferative capacity of adult pancreatic β-cells is critical to regenerative therapeutic approaches for diabetes. Here, we show that the microRNA (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 β-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 β-cell proliferation. Most importantly, this miR-7–mTOR proliferation axis is conserved in primary human β-cells, implicating miR-7 as a therapeutic target for diabetes.
This article contains Supplementary Data online at http://diabetes.diabetesjournals.org/lookup/suppl/doi:10.2337/db12-0451/-/DC1.
See accompanying commentary, p. 694.
- Received April 12, 2012.
- Accepted September 22, 2012.
- © 2013 by the American Diabetes Association.
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