MicroRNA-322 Regulates Self-renewal of Mouse Spermatogonial Stem Cells through Rassf8

Abstract

Spermatogonial stem cells (SSCs) are essential for spermatogenesis and male fertility. MicroRNAs (miRs) are key regulators of gene expression involved in self-renewal, differentiation, and apoptosis. However, the function and mechanisms of individual miR in regulating self-renewal and differentiation of SSCs remain unclear. Here, we report for the first time that miR-322 regulates self-renewal of SSCs. Functional assays revealed that miR-322 was essential for SSC self-renewal. Mechanistically, miR-322 promoted SSC self-renewal by targeting RASSF8 (ras association domain family 8). Moreover, the WNT/β-catenin signaling pathway was involved in the miR-322-mediated regulation. Furthermore, miR-322 overexpression increased GFRα1, ETV5 and PLZF expression but decreased STRA8, C-KIT and BCL6 expression. Our study provides not only a novel insight into molecular mechanisms regulating SSC self-renewal but also a basis for the diagnosis, treatment, and prevention of male infertility.

MicroRNA-30a-5p promotes differentiation in neonatal mouse spermatogonial stem cells (SSCs)

“…Furthermore, the ability of cultured cells for self-renewal and colony formation also confirmed that the cells were undifferentiated. These results were consistent with other studies [ 4 , 6 , 14 ]. According to the literature, Sertoli cells as the only somatic cells in the seminiferous tubules play vital roles in the regulation of the balance between SSCs self-renewal and differentiation by secreting many growth factors [ 40 ].…”

“…In line with this study, Chen et al found that miR-202-3p inhibitor induced differentiation in SSCs through reducing the expression of Plzf and increasing the expression of Stra8, Dazl and Sycp3 [ 15 ]. Wang et al also found that transfection of miR-322 inhibitor led a significant decrease in Gfrα1, Etv5 and Plzf expression and a marked increase in the expression of C-kit, stra8 and Bcl6 in mouse SSCs [ 4 ].…”

“…Spermatogenesis is a complex developmental process in the mammalian reproductive system that results in generation of highly specialized sperm from spermatogonial stem cells (SSCs) [ 1 , 2 ]. SSCs as the foundation cells are vital for spermatogenesis, but only form about 0.02–0.03 % of the total cell population in the adult mouse testis [ 3 , 4 ]. SSCs have some outstanding characteristics compared to other human stem cells.…”

“…For example, the high expression of miRNA-100 in SSCs promotes their proliferation by STAT3 [ 13 ]. Moreover, it has been reported that the self-renewal of SSCs is regulated by MiRNA − 10b and MiRNA − 322 [ 4 , 14 ]. Inhibition of cell cycle regulators and RNA binding proteins by MiRNA − 202 leads to the maintenance of spermatogonial stem cells [ 15 ].…”

Sperm miR‐15a and miR‐29b are associated with bull fertility

“…Several miRNAs have been identified in spermatozoa that have implications as critical regulators of apoptosis (Capra et al, ; Dai et al, ; Lv et al, ; Ma et al, ). Apoptosis regulates spermatogenesis (Wang, Li, Gong, Zhao, & Wu, ) and spontaneous programmed cell death in mature spermatozoa (Aitken & Baker, ; Engel, Springsguth, & Grunewald, ). Through analysis of miRNAs in sperm samples, researchers demonstrated their expression patterns in spermatozoa in different mammals including human (Heidary, Zaki‐Dizaji, Saliminejad, & Khorram Khorshid, ; Krawetz et al, ), boar (Godia et al, ), mouse (Hutcheon et al, ) and bull (Fagerlind et al, ).…”