Linling Cheng1, Jun Liu1, Bing Li2, Shengming Liu3, Xianyan Li3, Hongbin Tu4. 1. The State Key Laboratory of Respiratory Disease, National Clinical Center for Respiratory Diseases, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China. 2. Research Center for Experimental Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China. 3. Department of Respiratory Medicine, First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China. 4. The State Key Laboratory of Respiratory Disease, National Clinical Center for Respiratory Diseases, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China; Research Center for Experimental Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China. Electronic address: tuhongbin@mail.nih.gov.
Abstract
BACKGROUND: Cigarette smoking is a major environmental contributor to COPD, but understanding its epigenetic regulation of oxidative genes involved in the pathogenesis of COPD remains elusive. METHODS: We analyzed DNA methylation on glutamate-cysteine ligase catalytic subunit (GCLC), glutathione S-transferase M1 (GSTM1), glutathione S-transferase P1 (GSTP1), and superoxide dismutase 3 (SOD3) promoters in clinical samples from patients with COPD (current-smoker [CS-COPD]; ex-smoker [ES-COPD]) and subjects with normal pulmonary function (current-smoker [CS-NS]; ex-smoker [ES-NS]; never-smoker [NC]). Expression of GCLC messenger RNA (mRNA) and glutathione (GSH) synthesis in these clinical samples and human bronchial epithelial (BEAS-2B) cells stimulated by cigarette-smoke extract (CSE) was evaluated. GCLC mRNA and protein levels were measured to determine effects of demethylation and deacetylation agents on CSE-treated BEAS-2B cells. RESULTS: The DNA methylation level of the GCLC promoter was significantly increased in CS-COPD, CS-NS, and ES-COPD groups compared with ES-NS and NC groups. However, there were no significant differences in DNA methylation values of GSTM1, GSTP1, and SOD3 promoters among these groups. Expression of GCLC mRNA was downregulated in the lungs, and GSH levels decreased in plasma as a consequence of hypermethylation of the GCLC promoter. Similarly, CSE-treated BEAS-2B cells had hypermethylation of the GCLC gene, mRNA downregulation, and a decreased intracellular GSH level. GCLC expression in CSE-treated BEAS-2B cells was restored by the methylation inhibitor, 5-aza-2'-deoxycytidine, but not by the deacetylation agent, trichostatin A. CONCLUSIONS: Cigarette smoke-induced hypermethylation of the GCLC promoter is related to the initiation and progression of COPD. Our finding may provide a new strategy for COPD intervention by developing demethylation agents targeting GCLC hypermethylation.
BACKGROUND: Cigarette smoking is a major environmental contributor to COPD, but understanding its epigenetic regulation of oxidative genes involved in the pathogenesis of COPD remains elusive. METHODS: We analyzed DNA methylation on glutamate-cysteine ligase catalytic subunit (GCLC), glutathione S-transferase M1 (GSTM1), glutathione S-transferase P1 (GSTP1), and superoxide dismutase 3 (SOD3) promoters in clinical samples from patients with COPD (current-smoker [CS-COPD]; ex-smoker [ES-COPD]) and subjects with normal pulmonary function (current-smoker [CS-NS]; ex-smoker [ES-NS]; never-smoker [NC]). Expression of GCLC messenger RNA (mRNA) and glutathione (GSH) synthesis in these clinical samples and human bronchial epithelial (BEAS-2B) cells stimulated by cigarette-smoke extract (CSE) was evaluated. GCLC mRNA and protein levels were measured to determine effects of demethylation and deacetylation agents on CSE-treated BEAS-2B cells. RESULTS: The DNA methylation level of the GCLC promoter was significantly increased in CS-COPD, CS-NS, and ES-COPD groups compared with ES-NS and NC groups. However, there were no significant differences in DNA methylation values of GSTM1, GSTP1, and SOD3 promoters among these groups. Expression of GCLC mRNA was downregulated in the lungs, and GSH levels decreased in plasma as a consequence of hypermethylation of the GCLC promoter. Similarly, CSE-treated BEAS-2B cells had hypermethylation of the GCLC gene, mRNA downregulation, and a decreased intracellular GSH level. GCLC expression in CSE-treated BEAS-2B cells was restored by the methylation inhibitor, 5-aza-2'-deoxycytidine, but not by the deacetylation agent, trichostatin A. CONCLUSIONS: Cigarette smoke-induced hypermethylation of the GCLC promoter is related to the initiation and progression of COPD. Our finding may provide a new strategy for COPD intervention by developing demethylation agents targeting GCLC hypermethylation.
Authors: Jarrett D Morrow; Kimberly Glass; Michael H Cho; Craig P Hersh; Victor Pinto-Plata; Bartolome Celli; Nathaniel Marchetti; Gerard Criner; Raphael Bueno; George Washko; Augustine M K Choi; John Quackenbush; Edwin K Silverman; Dawn L DeMeo Journal: Am J Respir Crit Care Med Date: 2018-05-15 Impact factor: 30.528
Authors: Rachel Zeig-Owens; Ankura Singh; Thomas K Aldrich; Charles B Hall; Theresa Schwartz; Mayris P Webber; Hillel W Cohen; Kerry J Kelly; Anna Nolan; David J Prezant; Michael D Weiden Journal: Ann Am Thorac Soc Date: 2018-02