Detecting the distribution patterns of histone lactylation in the mouse testis at different developmental stages.

Lactate is a key glycolytic metabolite that serves as an energy substance and signaling molecule. Lactylation, a recently characterized posttranslational modification (PTM), has been identified in histone and nonhistone proteins. Compelling evidence suggests that this lactate-related epigenetic modification potently regulates gene expression under physiological and pathological conditions. However, the distribution of this histone modification in the testis remains largely unknown. In this study, we investigated the expression dynamics of histone acetyltransferases (HATs), histone deacetylases (HDACs), and the lactate-regulating enzyme hexokinase 2 (HK2), and examined the cellular distribution of several types of histone lactylation, which have been identified as important for transcription and chromatin accessibility, in mouse testes during critical postnatal developmental stages. The results revealed that the expression levels of the lactylation-associated transcripts were developmentally regulated and that the histone lactylation, including H3K9la, H3K12la and H4K18la were present in spermatogenic and Sertoli cells at postnatal days (PD) 0, 6, 21, and 60. However, signals for H3K5la and H3K14la were not detected in gonocytes at PD0 and signal for H3K14la was not detected in mature Sertoli cells or spermatogonia of adult testes. Furthermore, a lack of lactate dehydrogenase a (Ldha) in Sertoli cells impacted the localization of several histone lactylation modifications in spermatogenic cells. Notably, H4K12la was specifically detected in zygotene and diplotene spermatocytes in the control testis, whereas it was present mainly in spermatogonia of Lhda Sertoli cell conditional knockout testis (Ldha-cKO). The results of this study lay a foundation for further understanding the role of lactylation modification in spermatogenesis and provide important data for further dissectting the role of Sertoli cell-derived lactate in germ cell development.