miR-9-5p regulates Sirt1 involved in testicular development and spermatogenesis in mouse

Testicular development and spermatogenesis are critical for male reproduction, with histone (de)acetylation playing a key role in chromatin remodeling within germ cells. Sirt1, a key histone deacetylase, is implicated in chromatin remodeling, but its expression pattern and specific role in testicular development and spermatogenesis need further study. This study comprehensively analyzed Sirt1 expression in adult and juvenile mouse testicular tissues and across various male germ cells, utilizing RT-qPCR, Western blot, immunofluorescence, and cell transfection. GO and KEGG enrichment analyses were performed to elucidate the biological functions and pathways associated with Sirt1 and its related genes. Multiple miRNA databases were utilized to predict miRNAs targeting Sirt1, and their expression levels were validated using RT-qPCR. Lentiviral transfection was used to knockdown candidate miRNAs to assess their functional roles. The results revealed a significant downregulation of Sirt1 expression in adult mouse testicular tissues compared to juvenile tissues, with pronounced variation across diverse male germ cells. Sirt1 was highly expressed in spermatogonia and mature sperm, but comparatively lower in spermatocytes and spermatids. GO and KEGG enrichment analyses highlighted Sirt1's role in key biological processes, including chromatin organization, regulation of cell proliferation, and energy homeostasis, as well as its association with signaling pathways like cellular senescence, the FoxO signaling pathway, and the AMPK signaling pathway. Bioinformatic analysis and subsequent RT-qPCR validation identified miR-9-5p as a miRNA targeting Sirt1. The expression of miR-9-5p was significantly higher in adult mouse testicular tissues compared to juvenile tissues, inversely correlating with Sirt1 levels. Moreover, the knockdown of miR-9-5p led to a notable increase in Sirt1 mRNA and protein expression. In conclusion, Sirt1 is a key player in mouse testicular development and spermatogenesis. The discovery that miR-9-5p negatively regulates Sirt1 suggests a critical regulatory axis that may govern these processes, providing novel insights into male fertility and potential targets for therapeutic intervention.