Leydig Cell Medium

The testicular interstitium relies on coordinated signaling among vascular, steroidogenic, and structural cells, yet the regulatory role of testicular endothelial cells (... More

The testicular interstitium relies on coordinated signaling among vascular, steroidogenic, and structural cells, yet the regulatory role of testicular endothelial cells (TECs) in maintaining this homeostasis remains unclear. Here, we identify TECs as a central signaling hub that orchestrates intercellular communication within the human testis. Integrative single-cell transcriptomic analysis of healthy and diabetic testes reveals that diabetes disrupts platelet-derived growth factor (PDGF) signaling. TECs in diabetes undergo endothelial-to-mesenchymal transition and exhibit reduced PDGFB expression, while Leydig and testicular peritubular cells downregulate PDGFRB, collectively weakening intercellular connectivity. This disruption silences the JUND-MCL1 survival program in Leydig cells, leading to apoptosis, extracellular matrix accumulation, and testosterone insufficiency, while impairing the contractility of testicular peritubular cells. Importantly, exogenous PDGF-BB supplementation reactivates the JUND-MCL1 axis, protects Leydig cells, alleviates fibrosis, and partially restores testosterone production and peritubular function. Together, these findings establish endothelial PDGF dysregulation as a key driver of diabetic testicular pathology and highlight PDGF-BB supplementation as a mechanistically grounded therapeutic strategy to restore interstitial and endocrine function in the context of diabetes. Less

Leydig cells are the primary source of testosterone or androgen production in male mammals. The blood–testis barrier (BTB) maintains structural integrity and safeguards... More

Leydig cells are the primary source of testosterone or androgen production in male mammals. The blood–testis barrier (BTB) maintains structural integrity and safeguards germ cells from harmful substances by blocking their entry into the seminiferous tubules. L-cysteine is essential to the production of glutathione, a powerful antioxidant crucial to protecting against oxidative stress-induced damage. Animal studies have demonstrated the protective effect of L-cysteine in preventing testicular damage caused by chemicals or radiation. This study examines whether L-cysteine enhances the expression of testosterone biosynthesis and the BTB genes in human Leydig cells and THP-1 monocytes. The Leydig cells and THP-1 monocytes were treated with L-cysteine for 24 h. RNA was extracted following treatment, and the gene expression was analyzed using quantitative RT-PCR. Testosterone levels in the cell supernatant were measured using an ELISA kit. L-cysteine treatment in Leydig cells significantly upregulated the expression of CYP11A1 (p = 0.03) and the BTB genes CLDN1 (p = 0.03), CLDN11 (p = 0.02), and TJP1 (p = 0.02). Similarly, L-cysteine significantly upregulated the expression of CYP11A1 (p = 0.03) and CYP19A1 (p < 0.01), and the BTB genes CLDN1 (p = 0.04), CLDN2 (p < 0.01), CLDN4 (p < 0.01), CLDN11 (p < 0.01), and TJP1 (p = 0.03) in THP-1 monocytes. Further, L-cysteine supplementation increased the testosterone secretion levels in human Leydig cells. The findings suggest that L-cysteine supplementation could be used as an adjuvant therapy to promote the integrity of the BTB genes, testosterone biosynthesis and secretion, and the maintenance of testicular functions, which in turn mitigates the risk of male infertility. Less