The protective effect of PRMT6 overexpression on cigarette smoke extract-induced murine emphysema model
Authors He X, Li T, Kang N, Zeng H, Ren S, Zong D, Li J, Cai S, Chen P, Chen Y
Received 26 June 2017
Accepted for publication 26 September 2017
Published 3 November 2017 Volume 2017:12 Pages 3245—3254
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Charles Downs
Peer reviewer comments 2
Editor who approved publication: Dr Richard Russell
Xue He,1–3 Tiao Li,1–3 Naixin Kang,1–3 Huihui Zeng,1–3 Siying Ren,1–3 Dandan Zong,1–3 Jinhua Li,1–3 Shan Cai,1–3 Ping Chen,1–3 Yan Chen1–3
1Department of Respiratory Medicine, The Second Xiangya Hospital, 2Research Unit of Respiratory Disease, 3Diagnosis and Treatment Center of Respiratory Disease, Central South University, Changsha, Hunan, China
Background: Cigarette smoke exposure is the most common risk factor for emphysema, which is one of the major pathologies of COPD. Protein arginine methyltransferase 6 (PRMT6) is a nuclear enzyme that specially catalyzes dimethylation of R2 in histone H3 (H3R2me2a). H3R2me2a prevents trimethylation of H3K4 (H3K4me3), which is located in the transcription start sites of genes in mammalian genomes. We attempted to determine the expression of PRMT6 in human samples, and investigate whether the upregulation of PRMT6 expression can attenuate the development of cigarette smoke extract (CSE)-induced emphysema. Further experiments were performed to elucidate the molecular mechanisms involved.
Materials and methods: Human lung tissues were obtained from patients undergoing pneumonectomy for benign pulmonary lesions. BALB/c mice were treated with lentiviral vectors intratracheally and injected with CSE three times. The protein expression of PRMT6, H3R2me2a, and H3K4me3 in human and mouse samples, as well as B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and endothelial nitric oxide synthase (eNOS) in mice were detected in lung homogenates by Western blotting. The mRNA expression of cyclooxygenase-2, interleukin-6, Bcl-2, Bax, and eNOS in mice was measured by quantitative real-time polymerase chain reaction.
Results: The expression of PRMT6 was significantly downregulated in the pulmonary parenchyma in smokers with COPD as well as in mice treated with CSE. Overexpression of PRMT6 was detected in the CSE + Lenti-PRMT6 group of mice, which reversed the expression of H3R2me2a and H3K4me3. Inflammation, apoptosis, and oxidative stress levels were severe in the CSE-treated emphysema mice compared with the control group, which was inhibited by the overexpression of PRMT6.
Conclusion: The overexpression of PRMT6 might inhibit inflammation, apoptosis, and oxidative stress in CSE-induced emphysema mediated by H3R2me2a.
Keywords: COPD, cigarette smoke extract, inflammation, apoptosis, oxidative stress, PRMT6