Histone H3K27 demethylases inhibition restrains proliferation and promotes apoptosis of mouse spermatocyte

Background Spermatogenesis is pivotal to male reproduction and is tightly regulated by a variety of epigenetic regulators. However, the function of histone H3K27 demethylases JMJD3/UTX in spermatocytes and the mechanisms underlying their activities remain poorly defined.Methods We aimed to address the vital role of JMJD3/UTX enzymes in spermatocytes by pharmacologically inhibiting their activities using GSK-J4 in mice and in spermatocyte-derived GC-2 cells. The location and expression of JMJD3/UTX and their cognate substrate (H3K27me3) were characterized by immunofluorescence. Mice sperm quality was determined by haemocytometer and flow cytometry. Then, mice testis germ cells organization, proliferation, and apoptosis were evaluated by H&E, BrdU and TUNEL assay. Furthermore, in GC-2 cells after GSK-J4 treatment, cellular proliferation and apoptosis were tested by CCK-8, EdU, flow cytometry, and western blotting. At last, histone modifications including H3K4me3 and H3K27me3 were detected by western blot, and RNA-seq were conducted to find possible mechanism of GSK-J4 on spermatocytes.Results We confirmed that JMJD3/UTX is expressed in testis spermatocytes and in GC-2 cells. Compared with control, GSK-J4 recipient mice showed no alternations in sperm quality and testis morphology, but germ cells proliferation and apoptosis were affected. Furthermore, we demonstrated that JMJD3/UTX was implicated in GC-2 cell proliferation and apoptosis. At the same time, an upregulated H3K27me3 level and altered gene transcriptions associated with proliferation and apoptosis were observed.Conclusion Mice testis spermatocytes can express JMJD3/UTX, and these H3K27me3 demethylases plays a key role in the regulation of spermatocyte proliferation and apoptosis. H3K27me3 might be involved in the effects of JMJD3/UTX on spermatocytes.