miR-124-3p regulates the involvement of Ptpn1 in testicular development and spermatogenesis in mouse

Testicular development and spermatogenesis in mouse are a complex process in which phosphorylation modifications and regulation of genes by non-coding RNAs play an important role. However, protein tyrosine phosphatase, non-receptor type 1 (Ptpn1) is widely expressed in mammalian tissues. In this study, we analyzed the expression of Ptpn1 mRNA and its encoded proteins in testicular tissues of juvenile and adult mice by using experimental techniques such as biological information, real-time fluorescence quantitative PCR (RT-qPCR), western blot (WB), immunofluorescence (IF) and transfection, and further analyzed the possible target-regulatory relationship and regulatory mechanisms of miR-124-3p and Ptpn1. We found that Ptpn1 mRNA and its encoded protein were up-regulated in adult mouse testis compared to juvenile mouse testis. The expression trend of miR-124-3p was opposite to that of Ptpn1. In other cell types, Ptpn1 protein is localized in cell membrane, cytoplasm, endoplasmic reticulum and cytoplasmic vesicles. Immunofluorescence showed that Ptpn1 protein was mainly localized in the cytoplasm of male germ cells and was expressed at a high level in early-stage cells (spermatogonia) and at a low level in late-stage cells (sperm). Transfection results showed that the expression levels of Ptpn1 mRNA and its protein were significantly down-regulated after miR-124-3p overexpression in mouse spermatogonia. Bioinformatics analysis showed that Ptpn1 can involved in biological processes such as protein kinase inactivation through peptidyl tyrosine dephosphorylation. The reduction of miR-124-3p may be a key factor in promoting the high expression of Ptpn1 in testicular tissues of adult mice. Increased miR-124-3p may be a key factor in suppressing Ptpn1 expression in the mouse spermatogonia mimics group. The differential expression results from the negative regulation of miR-124-3p.