Abstract

Spermatogonial stem cells (SSCs) are the foundation for spermatogenesis which depends on the ability to self-renewal, thus any disorder of SSC biological function can result in infertility. SSC functions has important implications for understanding male infertility and its treatment by controlling self-renewal and differentiation. The fundamental mechanism underlying how SSCs acquire and maintain their self-renewal activity is of paramount importance. Several types of non-coding RNAs (ncRNAs), involving microRNA (miRNA), long noncoding RNA (lncRNA), piwi-interacting RNA (piRNA) and circular RNAs (circRNAs) play important roles in stem cell self-renewal by forming complicated epigenetic regulatory networks together with other epigenetic factors related to DNA methylation, histone methylation and acetylation. miRNAs, as critical regulator is involved in regulating self-renewal of many types of stem cell, miRNAs including miR-29b, miR-24, miR-29a, miR-199b, miR-199a, miR-27a, and miR-21 have been identified that are expressed in goat SSCs by comparing the miRNA expression profiles between CD49f-positive and CD49f-negative testicular cells using small RNA deep sequencing. Moreover, PLZF, an important transcription factor could up-regulate the expression level of CXCR4 to promote goat SSC proliferation by directly targeting miR-146a. Similarly, LncRNAs are important players in diverse cellular processes including proliferation, differentiation, apoptosis, senescence, stress response through complicated mechanisms involving lncRNA-mRNA, lncRNA-miRNA, lnRNA-DNA, lncRNA-protein. Also, some lncRNAs play critical regulatory roles in post-transcriptional and transcriptional regulation in self-renewal of SSCs. PIWI-interacting RNAs (piRNAs) are small non-coding RNAs primarily expressed in the germline cells. Furthermore, circRNAs play essential roles in various biological processes through modulating gene expression via multiple actions, such as in stem cell self-renewal and differentiation.

Keywords: SSCs; Self-renewal; Non-coding RNA

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