miRNA-93 Inhibits GLUT4 and Is Overexpressed in Adipose Tissue of Polycystic Ovary Syndrome Patients and Women With Insulin Resistance

  1. Ricardo Azziz1,10
  1. 1Department of Obstetrics/Gynecology, Georgia Regents University, Augusta, Georgia
  2. 2Department of Internal Medicine, The Catholic University of Korea, Seoul, South Korea
  3. 3Section of Reproductive Endocrinology, Infertility, & Genetics, Georgia Regents University, Augusta, Georgia
  4. 4Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, Georgia
  5. 5Neuroscience Program, Georgia Regents University, Augusta, Georgia
  6. 6Department of Physiology, Georgia Regents University, Augusta, Georgia
  7. 7Vascular Biology Center, Georgia Regents University, Augusta, Georgia
  8. 8Department of Surgery, Georgia Regents University, Augusta, Georgia
  9. 9Department of Obstetrics/Gynecology, Center for Health Sciences, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California
  10. 10Department of Medicine, Georgia Regents University, Augusta, Georgia
  1. Corresponding author: Ricardo Azziz, razziz{at}gru.edu.

Abstract

Approximately 70% of women with polycystic ovary syndrome (PCOS) have intrinsic insulin resistance (IR) above and beyond that associated with body mass, including dysfunctional glucose metabolism in adipose tissue (AT). In AT, analysis of the IRS/PI3-K/AKT pathway signaling components identified only GLUT4 expression to be significantly lower in PCOS patients and in control subjects with IR. We examined the role of miRNAs, particularly in the regulation of GLUT4, the insulin-sensitive glucose transporter, in the AT of PCOS and matched control subjects. PCOS AT was determined to have a differentially expressed miRNA profile, including upregulated miR-93, -133, and -223. GLUT4 is a highly predicted target for miR-93, while miR-133 and miR-223 have been demonstrated to regulate GLUT4 expression in cardiomyocytes. Expression of miR-93 revealed a strong correlation between the homeostasis model assessment of IR in vivo values and GLUT4 and miR-93 but not miR-133 and -223 expression in human AT. Overexpression of miR-93 resulted in downregulation of GLUT4 gene expression in adipocytes through direct targeting of the GLUT4 3′UTR, while inhibition of miR-93 activity led to increased GLUT4 expression. These results point to a novel mechanism for regulating insulin-stimulated glucose uptake via miR-93 and demonstrate upregulated miR-93 expression in all PCOS, and in non-PCOS women with IR, possibly accounting for the IR of the syndrome. In contrast, miR-133 and miR-223 may have a different, although yet to be defined, role in the IR of PCOS.

Footnotes

  • Received July 18, 2012.
  • Accepted March 8, 2013.

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  1. Diabetes vol. 62 no. 7 2278-2286
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