Vacuolar-ATPase isoform a2 regulates macrophages and cytokine profile necessary for normal spermatogenesis in testis.

a2V is required for maturation of sperm. The decreased expression of a2V at the feto-maternal interphase causes poor pregnancy outcome. The present study examined the role of a2V in spermatogenesis and inflammatory network in the testis. A single dose of anti-a2V mouse IgG or mouse IgG isotype (3 μg/animal) was injected i.p. into male mice on alternate days for 10 days. Anti-a2V-treated males exhibit severe deficiencies of spermatogenesis, which is indicated by the presence of less numbers of postmeiotic cells. Sperm counts and sperm motility were reduced significantly in anti-a2V-treated males. The release of the cleaved a2NTD was significantly lower in anti-a2V-treated testes. The TMs were identified as M2-like macrophages, and this population and the expression of various cytokines/chemokines (Tgf-β, Il-6, Nos2, Tnf, Lif, Mcp1, Ccl5) were decreased significantly in anti-a2V-treated testis compared with control testis. Moreover, the cleaved a2NTD acts as a key mediator of TMs and significantly up-regulates the secretion of testicular cytokines/chemokines, which are associated with normal spermatogenesis. When these anti-a2V-treated males were used for mating with normal females, the number of implantation sites was decreased significantly in the females mated with anti-a2V-treated males than the females mated with control males. These observations suggest that a2V plays a crucial role in spermatogenesis by regulating testicular immune responses, and its inhibition in males leads to poor pregnancy outcome in females.