Seminal exosomal miR-210-3p as a potential marker of Sertoli cell damage in Varicocele.

BACKGROUND: Varicocoele-associated stressors, such as hypoxia and heat, can damage cell function and viability, and some exosomal biomarkers released from impaired cells may reflect the cell status in testis. OBJECTIVES: To find if seminal exosomal microRNAs can reflect the Sertoli cell function in varicocoele. MATERIALS AND METHODS: Experimental left varicocoele rat model was established (n = 24), and patients with different grades of varicocoele (n = 104) were enrolled. Primary rat Sertoli cells were isolated with enzymatic hydrolysis. Exosomes were isolated from primary rat Sertoli cells, rat epididymis tissue, and human seminal plasma with polymer-based precipitation method. Exosomal microRNAs were quantified with qPCR. Inhibin-B was detected with enzyme immunoassay. The correlation analysis between microRNA and inhibin-B was evaluated with Spearman's correlation. RESULTS: We screened 12 previously reported hypoxia-responsive microRNAs in the primary rat Sertoli cells and found that 4 exosomal microRNAs increased significantly in response to in vitro hypoxia treatment (P < .05). Of the 4 microRNAs, only miR-210-3p was upregulated in the rats with experimental varicocoele (P < .01). In the patients with varicocoele, we found that seminal exosomal miR-210-3p significantly increased in patients with grade II and III varicocoele (P < .01), and miR-210-3p negatively correlated with sperm count (P < .01) and seminal inhibin-B expression (r = -0.39, P < .01). For the 30 patients with microsurgical varicocelectomy, the operation notably decreased miR-210-3p (P < .01). DISCUSSION AND CONCLUSION: Seminal exosomal miR-210-3p may be a novel, sensitive, and non-invasive biomarker of Sertoli cell damage in varicocoele.

Lipophagy Contributes to Testosterone Biosynthesis in Male Rat Leydig Cells.

In recent years, autophagy was found to regulate lipid metabolism through a process termed lipophagy. Lipophagy modulates the degradation of cholesteryl esters to free cholesterol (FC), which is the substrate of testosterone biosynthesis. However, the role of lipophagy in testosterone production is unknown. To investigate this, primary rat Leydig cells and varicocele rat models were administered to inhibit or promote autophagy, and testosterone, lipid droplets (LDs), total cholesterol (TC), and FC were evaluated. The results demonstrated that inhibiting autophagy in primary rat Leydig cells reduced testosterone production. Further studies demonstrated that inhibiting autophagy increased the number and size of LDs and the level of TC, but decreased the level of FC. Furthermore, hypoxia promoted autophagy in Leydig cells. We found that short-term hypoxia stimulated testosterone secretion; however, the inhibition of autophagy abolished stimulated testosterone release. Hypoxia decreased the number and size of LDs in Leydig cells, but the changes could be largely rescued by blocking autophagy. In experimental varicocele rat models, the administration of autophagy inhibitors substantially reduced serum testosterone. These data demonstrate that autophagy contributes to testosterone biosynthesis at least partially through degrading intracellular LDs/TC. Our observations might reveal an autophagic regulatory mode regarding testosterone biosynthesis.