Interleukin-2 receptor γ blocks the development of Leydig cells from stem/progenitor cells in male rats via JAK1-STAT3 pathway and GSDMD-mediated pyroptosis.

Interleukin-2 (IL-2) receptor γ (IL2RG) is present in the Leydig cell lineage, but its functional role remains elusive. To investigate how IL2RG impacts Leydig cell development from stem cells and elucidate the underlying mechanisms, we used a rat model of ethane dimethanesulfonate (EDS)-induced cell depletion in Wild-type (WT) and Il2rg knockout (KO) mice. WT and KO male rats received intratesticular IL-2 injections (1 and 10 ng/testis) from day 7 to day 21 post-EDS. Stem Leydig cells around tubules and isolated progenitor Leydig cells were cultured with IL-2 (1 and 10 ng/mL) with/without STAT3 inhibitor. Hormone levels, cell counts, gene/protein expression, and signaling pathways were analyzed. The results revealed that IL-2 significantly reduced serum testosterone levels in WT rats but had no effects in KO rats, without altering luteinizing hormone and follicle-stimulating hormone levels. Furthermore, IL-2 lowered Leydig cell numbers and the labeling index of PCNA in CYP11A1+ Leydig cells at 10 ng/testis, and downregulated the expression of SCARB1, HSD3B1, CYP17A1, SRD5A1, and NR5A1, as well as their corresponding mRNA levels in WT rats with no effect observed in KO rats. IL-2 also inhibited the incorporation of 5-ethynyl-2'-deoxyuridine (EdU) into stem Leydig cells in WT rats and [3H] thymidine incorporation into progenitor Leydig cells, as well as their differentiation. Importantly, the effects of IL-2 were reversed by the STAT3 inhibitor. Signaling pathway analysis showed that IL-2 exerted effects via increasing JAK1, STAT5, and STAT3 phosphorylation. This study provides insights into the inhibitory effects of IL2RG on Leydig cell development and highlights the involvement of the JAK-STAT pathway, offering potential targets for further exploration in the context of Leydig cell biology and male reproductive health.