TNF-α Suppressed FSH-Induced LH Receptor Expression Through Transcriptional Regulation in Rat Granulosa Cells

Several inflammatory cytokines regulate ovarian function. TNF-alpha is produced in granulosa cells under physiological conditions and has a reciprocal action on follicle development. In contrast, in pelvic inflammatory diseases, TNF-alpha is excessively produced in the pelvic cavity and has an adverse effect on reproductive functions. The objective of this study was to elucidate the mechanism of action of TNF-alpha on the expression of LH receptor (LHR) in immature rat granulosa cells. TNF-alpha suppressed FSH-induced LHR mRNA and protein expression and was not associated with cAMP accumulation. By using a luciferase assay, the construct containing base pairs -1389 to -1 of the rat Lhcgr promoter revealed that TNF-alpha decreased FSH-induced promoter activity. In response to TNF-alpha, nuclear factor (NF)-kappa B p65 was translocated to the nucleus, and the suppressive effect of TNF-alpha on LHR mRNA expression was abrogated by an NF-kappa B inhibitor. In a chromatin immuno-precipitation assay, TNF-alpha induced the association of NF-kappa B p65 with the rat Lhcgr transcriptional promoter region. NF-kappa B p65 and histone deacetylase (HDAC) interact to mediate expression of several genes at a transcriptional level. HDAC activity is thought to induce tight connections within local chromatin structures and repress gene transcription. Furthermore, the TNF-alpha-induced suppression of LHR mRNA expression was blocked by an HDAC inhibitor. Taken together, these results suggest that the interaction of NF-kappa B p65 with HDAC in the promoter region of rat Lhcgr might be responsible for TNF-alpha action on the regulation of LHR.