Oxidative stress links the tumour suppressor p53 with cell apoptosis induced by cigarette smoke.

This study was to investigate the effects of oxidative stress in cigarette smoke (CS)-induced cell apoptosis in mice with emphysema. Thirty-two mice were divided into four groups: the control group, the CS group, the CS + Pifithrin-α group, and the CS + NAC group. Pathological changes and apoptosis in lung tissue of mice were detected. The activity of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC) were measured using spectrophotometer. The proteins expression of p53, Bcl-2, Bax, and caspase-3 were determined by western blot. The results showed that cell apoptosis, lung structural damage, and the activity of MDA, as well as the expression of apoptosis-related proteins Bax, total caspase-3, and cleaved caspase-3 were increased in CS-treated mice. The activity of SOD, CAT, and T-AOC, as well as the expression of anti-apoptosis protein Bcl-2 were decreased in CS-treated mice when compared with the control group. However, Pifithrin-α (p53 inhibitor) and N-Acetylcysteine (NAC) could reduce cell apoptosis, lung structural damage and oxidative stress, accelerate the expression of Bcl-2, while suppressing the expression of Bax, total caspase-3 and cleaved caspase-3. More importantly, the treatment with NAC even inhibited the expression of p53. In conclusions, oxidative stress linking the p53 is involved in cell apoptosis in CS-treated emphysema mice.

Microarray Analysis of Long Non-Coding RNAs in Lung Tissues of Patients with COPD and HOXA-AS2 Promotes HPMECs Proliferation via Notch1.

Background and Objectives: Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of many diseases, including cancer, pulmonary fibrosis and chronic obstructive pulmonary disease (COPD). In this study, we intended to identify the differentially expressed lncRNAs and the role of HOXA cluster antisense RNA 2 (HOXA-AS2) in patients with COPD. Methods: We analyzed lncRNA profiles of three non-COPD and seven COPD patients' lungs via microarray and then validated the expression of the top differentially expressed lncRNAs by using real-time polymerase chain reaction (PCR). To identify the mechanism of HOXA-AS2 during COPD pathogenesis and endothelial cell proliferation, we knocked down and overexpressed HOXA-AS2 with siRNA and lentivirus transfection approach in human pulmonary microvascular endothelial cells (HPMECs). Results: Among 29,150 distinct lncRNA transcripts, 353 lncRNAs were significantly (≥2-fold change and P<0.05) upregulated and 552 were downregulated in COPD patients. The fold change of HOXA-AS2 is 9.32; real-time PCR confirmed that HOXA-AS2 was downregulated in COPD patients. In in vitro experiments, cigarette smoke extract (CSE) treatment reduced the expression of HOXA-AS2 and cell proliferation of HPMECs. Knocking down HOXA-AS2 inhibited HPMECs proliferation and the expression of Notch1 in HPMECs. Overexpressing Notch1 could partly rescue the inhibition of cell viability induced by the silence of HOXA-AS2. Conclusion: Our results demonstrated that differentially expressed lncRNAs may act as potential molecular biomarkers for the diagnosis of COPD, and HOXA-AS2 was involved in the pathogenesis of COPD by regulating HPMECs proliferation via Notch1, which may provide a new approach for COPD treatment.