SAT386 Constitutive Overexpression Of Microrna-93 As A Cause Of Metabolic Dysfunction And Hyperandrogenism In Polycystic Ovary Syndrome (PCOS): Evidence From A Transgenic (Mir-93+) Murine Model

Abstract

Abstract Disclosure: Y. Chen: None. H. Wu: None. B.A. Gower: None. R. Azziz: Advisory Board Member; Self; Arora Forge. Consulting Fee; Self; Fortress Biotech, Spruce Biosciences, Core Access Surgical Technologies, Rani Therapeutics. Grant Recipient; Self; Ferring Pharmaceuticals, Foundation for Research and Education Excellence. Stock Owner; Self; Martin Imaging. Background: PCOS appears to result from enhanced stimuli, either increased LH or insulin, and exaggerated responsiveness of ovarian theca cell androgen biosynthesis to these stimuli. However, the etiology of the enhanced stimuli remains unclear. We previously reported that a specific microRNA, miR-93, regulates GLUT4 content in adipocytes; and that in PCOS miR-93 overexpression in adipocytes results in suppressed GLUT4 expression and insulin-meditated glucose uptake in these cells, and is associated with whole-body insulin resistance (IR). These data suggest that constitutive miR-93 overexpression may underly the metabolic dysfunction and, possibly, the hyperandrogenism of PCOS. Objective: To test the hypothesis in a transgenic murine model that miR-93 overexpression results in the metabolic and hyperandrogenic features of PCOS. Materials and methods: We generated a novel miR-93 overexpressed (miR-93+) mouse model in collaboration with InGenious Targeting Laboratory (Ronkonkoma, NY). The mouse miR-93 sequence with the R26/CAG promoter was inserted immediately downstream of loxP flanked stop cassette in intron 1 of ROSA26 locus. miR-93 insertion was not expected to cause unwanted phenotypes resulting from modification of the Rosa26 locus. When mating miR-93+ transgenic mice to whole body Cre mice (The Jackson Lab) the stop code is removed, and miR-93 is overexpressed systemically. Results: In miR-93+ mice, miR-93 was overexpressed in adipose tissue (AT), muscle, liver, heart, kidneys, and ovaries. Phenotypically, miR-93+ mice had reduced GLUT4 expression in AT, and higher fasting serum insulin, higher fasting serum glucose, and higher testosterone levels. In PCOS women, increased CYP17A1 expression in theca cells is associated with excess androgen production. Consistent with this PCOS phenotype, Cyp17a1 expression in miR-93+ mice ovaries were also increased. In addition, the ovaries of miR-93+ mice had reduced expression of Cdkn1a, similar to that observed in granulosa cells from PCOS patients. miR-93+ mice gained more weight and epididymal AT than controls. miR-93+ mice also demonstrated a lesser response to insulin during an insulin tolerance test (ITT) and exhibited altered estrous cycles as compared to wild type. Conclusion: We successfully developed a miR-93 overexpressed (miR93+) murine model, which demonstrates IR, hyperandrogenemia, exaggerated ovarian Cyp17a1 expression, increased weight gain, and abnormal estrous (ovulatory) cyclicity, mimicking the PCOS phenotype. These results provide further evidence to support the role for constitutive overexpression of miR-93 in the metabolic and hyperandrogenic features of PCOS. These data also suggest a potential model to study the mechanisms mediating the effect of miR-93 overexpression on IR and on the PCOS phenotype in tissues and conditions not readily accessible in human subjects. Presentation Date: Saturday, June 17, 2023