Tsai-Der Chuang1, Omid Khorram2. 1. Department of Obstetrics and Gynecology Harbor-University of California Los Angeles Medical Center and Los Angeles Biomedical Research Institute, Torrance, California. 2. Department of Obstetrics and Gynecology Harbor-University of California Los Angeles Medical Center and Los Angeles Biomedical Research Institute, Torrance, California. Electronic address: okhorram@labiomed.org.
Abstract
OBJECTIVE: To determine the expression of miR-29c and its target gene transforming growth factor-β3 (TGF-β3) in leiomyoma and the mechanisms of their reciprocal regulation. DESIGN: Experimental study. SETTING: Academic research laboratory. PATIENT(S): Women undergoing hysterectomy for leiomyoma. INTERVENTION(S): Overexpression and underexpression of miR-29c; blockade of DNA methyltransferase 1 (DNMT1). MAIN OUTCOME MEASURE(S): The miR-29c and its target gene TGF-β3 in leiomyoma and the effects of TGF-β3 and blockade of DNMT1 on miR-29c expression. RESULT(S): Leiomyoma expressed significantly lower levels of miR-29c, but higher expression of TGF-β3 compared with matched myometrium. The expression of TGF-β3 and miR-29c were independent of race/ethnicity. Using 3' untranslated region luciferase reporter assay we confirmed that TGF-β3 is a direct target of miR-29c in leiomyoma smooth muscle cells (LSMCs). Gain-of-function of miR-29c in LSMCs inhibited the expression of TGF-β3 at protein and messenger RNA levels, whereas loss-of-function of miR-29c had the opposite effect. Treatment of LSMCs with TGF-β3 inhibited the expression of miR-29c, whereas it stimulated DNMT1 expression. Knockdown of DNMT1 through transfection with small interfering RNA significantly decreased the expression of TGF-β3, and induced miR-29c expression. Knockdown of DNMT1 also attenuated the inhibitory effect of TGF-β3 on miR-29c expression. Furthermore, we demonstrated that TGF-β3 increased the methylation level of miR-29c promoter in LSMCs. CONCLUSION(S): There is an inverse relationship in the expression of TGF-β3 and miR-29c in leiomyoma. The TGF-β3 is a direct target of miR-29c and inhibits the expression of miR-29c through an epigenetic mechanism. The cross-talk between miR-29c and TGF-β3 provides a feed forward mechanism of fibrosis in leiomyoma.
OBJECTIVE: To determine the expression of miR-29c and its target gene transforming growth factor-β3 (TGF-β3) in leiomyoma and the mechanisms of their reciprocal regulation. DESIGN: Experimental study. SETTING: Academic research laboratory. PATIENT(S): Women undergoing hysterectomy for leiomyoma. INTERVENTION(S): Overexpression and underexpression of miR-29c; blockade of DNA methyltransferase 1 (DNMT1). MAIN OUTCOME MEASURE(S): The miR-29c and its target gene TGF-β3 in leiomyoma and the effects of TGF-β3 and blockade of DNMT1 on miR-29c expression. RESULT(S): Leiomyoma expressed significantly lower levels of miR-29c, but higher expression of TGF-β3 compared with matched myometrium. The expression of TGF-β3 and miR-29c were independent of race/ethnicity. Using 3' untranslated region luciferase reporter assay we confirmed that TGF-β3 is a direct target of miR-29c in leiomyoma smooth muscle cells (LSMCs). Gain-of-function of miR-29c in LSMCs inhibited the expression of TGF-β3 at protein and messenger RNA levels, whereas loss-of-function of miR-29c had the opposite effect. Treatment of LSMCs with TGF-β3 inhibited the expression of miR-29c, whereas it stimulated DNMT1 expression. Knockdown of DNMT1 through transfection with small interfering RNA significantly decreased the expression of TGF-β3, and induced miR-29c expression. Knockdown of DNMT1 also attenuated the inhibitory effect of TGF-β3 on miR-29c expression. Furthermore, we demonstrated that TGF-β3 increased the methylation level of miR-29c promoter in LSMCs. CONCLUSION(S): There is an inverse relationship in the expression of TGF-β3 and miR-29c in leiomyoma. The TGF-β3 is a direct target of miR-29c and inhibits the expression of miR-29c through an epigenetic mechanism. The cross-talk between miR-29c and TGF-β3 provides a feed forward mechanism of fibrosis in leiomyoma.
Authors: James H Segars; Estella C Parrott; Joan D Nagel; Xiaoxiao Catherine Guo; Xiaohua Gao; Linda S Birnbaum; Vivian W Pinn; Darlene Dixon Journal: Hum Reprod Update Date: 2014-01-08 Impact factor: 15.610