Tumor necrosis factor alpha affect hydrocortisone expression in mice adrenal cortex cells mainly through tumor necrosis factor alpha-receptor 1

Background Tumor necrosis factor alpha （TNF-α） is important in promoting relative adrenal insufficiency （RAI） due to systemic inflammatory response syndrome （SIRS）. We identified the TNF-α receptor involved in the inhibition of adrenal corticotrophin （ACTH）-stimulated hydrocortisone release by studying the expression of TNF-α receptors in adrenal cortex Y1 cells and the effect of downregulating TNF receptors on ACTH-stimulated hydrocortisone release. Methods We used real-time PCR and immunocytochemistry to evaluate the expression of TNF receptors on Y1 cells. TNF-receptor 1 （TNF-R1） DNA fragments corresponding to the short hairpin RNA （shRNA）-sequences were synthesized and cloned into pcDNATM 6.2-GW/EmGFP expression vector. Knockdown efficiency of TNF-R1 expression was evaluated in miRNA transfected and mock-miRNA transfected Y1 cells by quantitative real-time PCR （Q-PCR）. Hydro- cortisone expression levels were determined in TNF-Rl-knockdown and control Y1 cells treated with TNF-α and ACTH. Results Mouse adrenal cortex Y1 cells were positive for type I TNF-R1, but not type II TNF-receptor （TNF-R2）. Blocking TNF-R1 expression resulted in loss of TNF-a-mediated inhibition of ACTH-stimulated hydrocortisone expression suggesting a role for the TNF-R1 related signaling pathway in ACTH-stimulated hydrocortisone synthesis. Conclusion The inhibitory effect of TNF-α on ACTH-stimulated hydrocortisone synthesis was mediated via TNF-R1 in adrenal cortex.