Expression of GLOD4 in the Testis of the Qianbei Ma Goat and Its Effect on Leydig Cells

The expression pattern of <i>GLOD4</i> in the testis and its regulatory effect on testicular cells was explored in goats to enhance our understanding of spermatogenesis and improve reproduction in breeding rams. In this study, we demonstrated the localization of <i>GLOD4</i> in testicular cells using immunohistochemistry and subcellular localization analyses. Subsequently, we analyzed the <i>GLOD4</i> expression pattern in four age-based groups (0, 6, 12, and 18 months old) using real-time quantitative polymerase chain reaction (qRT-PCR) and protein blotting. Finally, we performed <i>GLOD4</i> silencing and overexpression studies in Leydig cells (LCs) and explored the effects on cell proliferation, the cell cycle, steroid hormone secretion and the expression of candidate testosterone hormone-regulated genes. <i>GLOD4</i> was mainly expressed in Leydig cells, and the subcellular localization results showed that the GLOD4 protein was mainly localized in the cytoplasm and nucleus. Silencing of <i>GLOD4</i> significantly suppressed the mRNA expression levels of the testosterone secretion-related genes <i>CYP11A1</i>, <i>3β-HSD</i>, and <i>CYP17A1</i> and the mRNA expression levels of cell cycle-related genes <i>CDK6</i>, <i>PCNA</i>, and <i>Cyclin E</i>. Moreover, the cell cycle was blocked at the G2/M phase after <i>GLOD4</i> silencing, which significantly suppressed testosterone secretion. In contrast, <i>GLOD4</i> overexpression significantly increased the mRNA expression levels of the testosterone secretion-related genes <i>CYP11A1</i>, <i>3β-HSD</i>, and <i>CYP17A1</i> and increased the expression of the cell cycle-related genes <i>CDK6</i>, <i>PCNA</i>, and <i>Cyclin E</i>. Moreover, <i>GLOD4</i> overexpression promoted the cell cycle from G0/G1 phases to enter the S phase and G2/M phases, promoted the secretion of testosterone. Taken together, our experimental results indicate that <i>GLOD4</i> may affect the development of cells in Qianbei Ma goats of different ages by influencing the cell cycle, cell proliferation, and testosterone hormone synthesis. These findings enhance our understanding of the functions of <i>GLOD4</i> in goats.