HO-1在桑黃萃取物Hispolon抑制巨噬細胞iNOS/NO產生之機轉

Abstract

Abstract • Hispolon (HIS) isolated form Chinese Herbs Phellinus linteus (PL) has been shown to exhibit several benefitcal activities such as anti-oxidant and anti-tumour, however the mechanism of HIS on inflammation Nitric oxide (NO) and inducible Nitric oxide synthases (iNOS) is still unknown. In the present study HIS exhibited a dose- and time-dependent inhibition on iNOS/NO expression elicited by Lipopolysaccharde (LPS), Lipoteichoic acid (LTA) and Peptidoglycan (PGN) accompanied by induciion heme oxygenase-1 (HO-1) gene expression in macrophages RAW264.7. An increase in intracellular reactive Oxygen species (ROS) at both protein and mRNA level was detected in HIS-treated macrophages, and HIS-induced HO-1 protein was abolished by ROS inhibitor N-acetyl cysteine (NAC). Additionally, HIS reduction LPS, LTA, and PGN-induced iNOS/NO expression was attenuated by adding HO inhibitors SnPP, and HO-1 siRNA. HIS-inhibited NO production was mediated by suppressing NF-kB and AP-1 activation, without affecting iNOS protein and mRNA stability. Suppression of LPS, LTA and PGN-induced JNK protein phosphorylation by HIS was identified. Furthermore, apoptosis induced by LPS, LTA, and PGN was observed in macrophages RAW264.7, and that was prevented by adding NOS inhibitor L-NAME and NLA with reducing NO production. HIS incubation significantly protected RAW264.7 macrophages from LPS, LTA, and PGN-induced apoptosis, characterized by DNA ladders, caspases activation, and flow cytometry analysis. Benefical effects of HIS in protection of RAW264.7 cells form apoptosis via reducing iNOS/NO production were demonstrated.