HDAC inhibitor prevents LPS mediated inhibition of CYP19A1 expression and 17β-estradiol production in granulosa cells.

LPS inhibits CYP19A1 expression and 17β-estradiol (E2) production in granulosa cells (GCs). This is one of the major causes of infertility underlying postpartum uterine infections. However, the precise molecular mechanism is not well elucidated. Recently we have shown, buffalo GCs exposed to LPS (1.0 μg/ml) in serum free culture, transiently increased the pro-inflammatory cytokine genes (IL-1β, TNF-α, IL-6) expression, followed by the inhibition of CYP19A1 expression and E2 production. The present study showed that transient increase in pro-inflammatory cytokines was associated with HDACs (gene expression and nuclear activity). Therefore, we tested the hypothesis if Trichostatin A (TSA), a HDAC inhibitor, can attenuate LPS induced pro-inflammatory cytokine gene expression and can prevent LPS mediated down-regulation of CYP19A1 expression and E2 in GCs. Results showed that TSA pre-treatment significantly attenuated LPS induced pro-inflammatory cytokine gene expressions, HDACs (both gene expression and enzyme activity in nucleus) and NF-κB nuclear translocation. Additionally, TSA pre-treatment reversed the inhibitory effect of LPS on CYP19A1 expression and E2 production. CHIP analyses of H3 (Lys 9/14) acetylation of ovary specific CYP19A1 proximal promoter (PII) showed that TSA pre-treatment prevented the LPS mediated H3 deacetylation, thereby increased the acetylation of PII and restored CYP19A1 expression and E2 production. The present study demonstrated that TSA pre-treatment attenuated- LPS induced immune response involving NF-κB and HDACs, and thus prevented inhibition of CYP19A1 expression and E2 production through chromatin remodeling. Our study suggests that HDAC inhibitors could be a potential therapeutic strategy to treat infertility underlying postpartum uterine infections.