Homocysteine Triggers Inflammatory Responses in Macrophages through Inhibiting CSE-H2S Signaling via DNA Hypermethylation of CSE Promoter

International Journal of Molecular Sciences

Jiao-Jiao Li²  Qian Li¹  Hua-Ping Du²  Ya-Li Wang²  Shou-Jiang You²  Fen Wang²  Xing-Shun Xu²  Jian Cheng¹  Yong-Jun Cao²  Chun-Feng Liu²  Li-Fang Hu² 

[1]Institute of Neuroscience, Soochow University, Suzhou 215123, China

[2] E-Mails:

[3]Department of Neurology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, the Second Affiliated Hospital of Soochow University, Soochow University, Suzhou 215004, China

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关键词: homocysteine;    cystathionine γ-lyase;    hydrogen sulfide;    macrophage;    DNA methylation;   

DOI  :  10.3390/ijms160612560

来源: mdpi

【 摘 要 】

Hyperhomocysteinemia (HHcy) is an independent risk factor of atherosclerosis and other cardiovascular diseases. Unfortunately, Hcy-lowering strategies were found to have limited effects in reducing cardiovascular events. The underlying mechanisms remain unclear. Increasing evidence reveals a role of inflammation in the pathogenesis of HHcy. Homocysteine (Hcy) is a precursor of hydrogen sulfide (H₂S), which is formed via the transsulfuration pathway catalyzed by cystathionine β-synthase and cystathionine γ-lyase (CSE) and serves as a novel modulator of inflammation. In the present study, we showed that methionine supplementation induced mild HHcy in mice, associated with the elevations of TNF-α and IL-1β in the plasma and reductions of plasma H₂S level and CSE expression in the peritoneal macrophages. H₂S-releasing compound GYY4137 attenuated the increases of TNF-α and IL-1β in the plasma of HHcy mice and Hcy-treated raw264.7 cells while CSE inhibitor PAG exacerbated it. Moreover, the in vitro study showed that Hcy inhibited CSE expression and H₂S production in macrophages, accompanied by the increases of DNA methyltransferase (DNMT) expression and DNA hypermethylation in cse promoter region. DNMT inhibition or knockdown reversed the decrease of CSE transcription induced by Hcy in macrophages. In sum, our findings demonstrate that Hcy may trigger inflammation through inhibiting CSE-H₂S signaling, associated with increased promoter DNA methylation and transcriptional repression of cse in macrophages.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.