The targeting and functions of miRNA-383 are mediated by FMRP during spermatogenesis

Abstract

Our previous studies have shown that microRNA-383 (miR-383) expression is downregulated in the testes of infertile men with maturation arrest (MA). Abnormal testicular miR-383 expression may potentiate the connections between male infertility and testicular germ cell tumors. However, the mechanisms underlying the targeting and functions of miR-383 during spermatogenesis remain unknown. In this study, we found that fragile X mental retardation protein (FMRP) was associated with 88 miRNAs in mouse testis including miR-383. Knockdown of FMRP in NTERA-2 (NT2) (testicular embryonal carcinoma) cells enhanced miR-383-induced suppression of cell proliferation by decreasing the interaction between FMRP and miR-383, and then affecting miR-383 binding to the 3′-untranslated region of its target genes, including interferon regulatory factor-1 (IRF1) and Cyclin D1 both in vivo and in vitro. On the other hand, FMRP levels were also downregulated by overexpression of miR-383 in NT2 cells and GC1 (spermatogonia germ cell line). miR-383 targeted to Cyclin D1 directly, and then inhibited its downstream effectors, including phosphorylated pRb and E2F1, which ultimately resulted in decreased FMRP expression. Reduced miR-383 expression, dysregulated cyclin-dependent kinase 4 expression (one of the downstream genes of miR-383) and increased DNA damage were also observed in the testes of Fmr1 knockout mice and of MA patients with a downregulation of FMRP. A potential feedback loop between FMRP and miR-383 during spermatogenesis is proposed, and FMRP acts as a negative regulator of miR-383 functions. Our data also indicate that dysregulation of the FMRP–miR-383 pathway may partially contribute to human spermatogenic failure with MA.

A Chromatin-Dependent Role of the Fragile X Mental Retardation Protein FMRP in the DNA Damage Response

“…Our findings suggest that the rate of germline chromosomal instability among Fmr1 knockout mice or fragile X patients at sites outside the fragile X locus may be elevated. This hypothesis is supported by recent findings describing increased rates of DNA damage and apoptosis in spermatocytes of Fmr1 KO mice (Tian et al, 2013). In addition, low FMRP levels were correlated with spermatogenesis defects in maturation arrest (MA) patients (Tian et al, 2013).…”

“…This hypothesis is supported by recent findings describing increased rates of DNA damage and apoptosis in spermatocytes of Fmr1 KO mice (Tian et al, 2013). In addition, low FMRP levels were correlated with spermatogenesis defects in maturation arrest (MA) patients (Tian et al, 2013). Thus, our findings provide a potential molecular mechanism for the DNA damage, apoptosis and spermatogenesis defects observed in mice and patients lacking FMRP.…”

Prognostic and predictive roles of microRNA-383 in colorectal cancer

“…24 Moreover, it is reported that expression of miR-383 was downregulated in patients with non-obstructive azoospermia. [24][25][26] In another research, it was found that miR-383 straightly targeted insulinlike growth factor 1 receptor (IGF1R). Downregulation of miR-383 promotes glioma cell invasion by targeting IGF1R; it also results in the activation of AKT signaling following upregulation of matrix metalloproteinase-2.…”

STAT3 regulated ATR via microRNA-383 to control DNA damage to affect apoptosis in A431 cells

“…It was recently shown that miR-383 inhibited the focal formation and abundance of γH2AX, which is the major marker of sites of DNA damage, with or without ultraviolet irradiation and cisplatin in testicular embryonal carcinoma (NT-2) cells (24), and the targeting and functions of miRNA-383 are mediated by FMRP during spermatogenesis (36). In addition, transactivation of miRNA-383 by steroidogenic factor-1 promotes estradiol release from mouse ovarian granulosa cells by targeting RBMS1 (37).…”