MicroRNA-30d and microRNA-181a regulate the expression of HOXA11 in the uterosacral ligaments and are overexpressed in pelvic organ prolapse

Abstract

Objectives: The balance between the synthesis and degradation of collagen is important in maintaining the structural integrity and tensile strength of pelvic supportive connective tissues. Homeobox A11 (HOXA11) is a key transcriptional factor that regulates collagen metabolism, and its expression is decreased in the uterosacral ligaments (USLs) of women with pelvic organ prolapse (POP). The aim of the present study was to identify specific microRNAs (miRNAs) involved in the regulation of HOXA11 expression in the USLs and to define their biologically functional effects.Methods: miRNA expression was assessed in the USLs of women with and without POP using microarray and quantitative real-time polymerase chain reaction (RT-PCR) analysis. To determine the role of selected miRNAs in the regulation of HOXA11, 293T cells were transfected with miR mimic, anti-miR or negative controls. Then, quantitative RT-PCR, Western blotting and luciferase reporter assays were performed.Results: MiR-30d and miR-181a were overexpressed in the USLs of women with POP, and the expression of both miRNAs was inversely correlated with HOXA11 mRNA expression. In cultured 293T cells, the overexpression of miR-30d/181a suppressed HOXA11 mRNA and protein levels, whereas knockdown of these miRNAs enhanced HOXA11 levels. Cotransfection of a luciferase reporter plasmid containing the 3′-UTR of HOXA11 with miR-30d/181a mimics resulted in decreased relative luciferase activity. Conversely, cotransfection with anti-miR-30d/181a increased the relative luciferase activity.Conclusion: These results indicate that both miR-30d and miR-181a directly downregulate HOXA11 expression at the posttranscriptional level and that the decreased HOXA11 expression in the USLs of women with POP might be caused by the aberrant expression of these miRNAs. Therefore, therapeutic approaches aimed at decreasing these miRNAs might be useful for restoring the altered collagen metabolism and homeostasis in the USLs that leads to POP.