Effect of endometriosis-linked microRNAs on hepatic gene expression.

Objective: To determine if microRNAs that are altered in the circulation of women with endometriosis affect metabolic gene expression in hepatic cells.

Design: In vitro study.

Setting: Academic Medical Center. HUMAN HEPG2 CELLS: MiR-let-7b, miR-125b-5p, miR-150-5p, and miR-3613-5p, their inhibitors or respective controls were transfected in human HepG2 cells.

Intervention(s): MicroRNAs were used to induce or suppress target genes in hepatic cells.

Main Outcome Measure(s): Effect of the microRNAs that are aberrantly expressed in endometriosis on hepatic cell gene expression using qPCR.

Result(s): Prior microarray studies on serum of women with endometriosis showed differential expression of microRNAs miR-Let-7b, miR-125b-5p, miR-150-5p, and miR-3613-5p. Bioinformatic analyses revealed that these microRNAs have predicted binding sites in multiple genes that are involved in liver metabolism. Transfection of these miRs in HepG2 cells followed by qRT-PCR showed that miR-Let-7b mimic increased the expression of Igfbp1 by 8-fold (p = 0.004) and reduced the expression of Mrc1 by 3.2-fold (p = 0.003) while its inhibitor reduced Igfbp1 by 2.8-fold (p = 0.0004) and increased Mrc1 by 5.2-fold (p = 0.04). MiR-3613-5p mimic reduced the expression of Cyp2r1 by 2.2-fold (p = 0.04) and Mrc1 by 4-fold (p= 0.0001). MiR-125b-5p mimic increased the expression of Fabp4 by 4.1-fold (p = 0.020) while miR-150-5p mimic increased the expression of Mrc1 by 1.8-fold (p = 0.01) and Cyp2r1 by 2.5-fold (p = 0.008). Inhibitors of both miR-125b-5p and miR-150-5p did not show any effect on any of the genes.

Conclusion(s): Circulating microRNAs known to be aberrant in endometriosis regulated hepatic gene expression, likely contributing to the metabolic defects seen in this disease. Treatment with miR-Let-7b and miR-3613-5p, which are downregulated in endometriosis, reversed the effect of endometriosis on the expression of IGFBP1, MRC1 and CYP2r1 genes. Therefore, miR-Let-7b and miR-3613-5p may be novel candidate therapies for endometriosis, potentially correcting the metabolic changes seen in endometriosis patients.