HDAC9 inhibition reduces skeletal muscle atrophy and enhances regeneration in mice with cigarette smoke-induced COPD.

Cigarette smoke (CS) is the major risk factor for chronic obstructive pulmonary disease (COPD), and sarcopenia is one of the significant comorbidities of COPD. However, the pathogenesis of CS-related deficient skeletal muscle regeneration has yet to be clarified. The impact of CS on myoblast differentiation was examined, and then we determined which HDAC influenced the myogenic process and muscle atrophy in vitro and in vivo. Finally, we further investigated the potential mechanisms via RNA sequencing. Long-term CS exposure activated skeletal muscle primary satellite cells (SCs) while inhibiting differentiation, and defective myogenesis was also observed in C2C12 cells treated with CS extract (CSE). The level of HDAC9 changed in vitro and in vivo in CS exposure models as well as COPD patients, as detected by bioinformatics analysis. Our data showed that CSE impaired myogenic capacity and myotube formation in C2C12 cells via HDAC9. Moreover, inhibition of HDAC9 in mice exposed to CS prevented skeletal muscle dysfunction and promoted SC differentiation. The results of RNA-Seq analysis and verification indicated that HDAC9 knockout improved muscle differentiation in CS-exposed mice, probably by acting on the AKT/mTOR pathway and inhibiting the P53/P21 pathway. More importantly, the serum of HDAC9 KO mice exposed to CS alleviated the differentiation impairment of C2C12 cells caused by serum intervention in CS-exposed mice, and this effect was inhibited by LY294002 (an AKT/mTOR pathway inhibitor). These results suggest that HDAC9 plays an essential role in the defective regeneration induced by chronic exposure to CS.

Prognostic significance of circulating Epstein-Barr virus DNA in pulmonary lymphoepithelioma-like carcinoma: A meta-analysis and validation study.

In small-scale studies, circulating Epstein-Barr virus (EBV) DNA levels have prognostic value in patients with pulmonary lymphoepithelioma-like carcinoma (LELC). Therefore, we performed a comprehensive meta-analysis to evaluate the prognostic significance of circulating EBV DNA levels in patients with pulmonary LELC. Studies that discussed the prognostic significance of circulating EBV DNA detection in pulmonary LELC were eligible for inclusion in this study. The overall survival (OS) and progression-free survival (PFS) were the primary outcomes. Pooled hazard ratio (HR), 95% confidence intervals (CIs), and p value were calculated to estimate the prognostic significance of EBV DNA levels. Additionally, we conducted a further observation using an independent cohort. The pooled HR and 95% CI of pretreatment EBV DNA levels for OS and PFS were 3.63 (95% CI: 2.90-4.55) and 2.88 (95% CI: 1.90-4.38), respectively. The pooled HR and 95% CI for Posttreatment EBV DNA levels for OS and PFS were 3.77 (95% CI: 2.96-4.80) and 3.52 (95% CI: 1.91-6.51, p < 0.001), respectively. The independent cohort showed similar results that patients with high pretreatment EBV DNA or positive posttreatment EBV DNA had significantly inferior PFS. Circulating EBV DNA levels provide prognostic values of survival and treatment response in pulmonary LELC patients.

Resveratrol Prevents Skeletal Muscle Atrophy and Senescence via Regulation of Histone Deacetylase 2 in Cigarette Smoke-Induced Mice with Emphysema.

Objective: The aim of this study was to investigate the effects of resveratrol (RSV) on cigarette smoke (CS)-induced skeletal muscle atrophy and senescence in mice with emphysema and to explore the underlying mechanisms. Methods: Gastrocnemius muscle weight and lung and muscular morphology were observed in CS-exposed mice with or without RSV treatment. The expression of atrophy-related markers (MURF1 and MAFbx), senescence-related markers (P53, P21 and SMP30) and NF-κB inflammatory pathways was detected by Western blotting and real-time PCR. The levels of IL-1ß and TNF-α were also determined by ELISA, and the number of senescent cells was determined by SA-ß gal staining. In addition, the expression of HDAC2 and the effect of HDAC2 on CSE-induced skeletal muscle atrophy and senescence by RSV treatment were investigated. Results: RSV prevented emphysema and skeletal muscle atrophy in long-term CS-exposed mice. RSV decreased the expression of MURF1, MAFbx, P53, and P21 and inhibited the NF-κB pathway both in vivo and in vitro. Moreover, RSV reversed CS-induced downregulation of HDAC2 expression both in gastrocnemius and in C2C12 cells. Moreover, knockdown of HDAC2 significantly abolished the inhibitory effect of RSV on the expression of MURF1, MAFbx, P53, P21 and inflammatory factors (IL-1ß and TNF-α) in C2C12 cells. Conclusion: RSV prevents CS-induced skeletal muscle atrophy and senescence, and upregulation of HDAC2 expression and suppression of inflammation are involved.

Histone Deacetylase 2 Suppresses Skeletal Muscle Atrophy and Senescence via NF-κB Signaling Pathway in Cigarette Smoke-Induced Mice with Emphysema.

Background: Exposure to cigarette smoke (CS) is the main risk factor for chronic obstructive pulmonary disease (COPD). CS not only causes chronic airway inflammation and lung damage but also is involved in skeletal muscle dysfunction (SMD). Previous studies have shown that histone deacetylase 2 (HDAC2) plays an important role in the progression of COPD. The aim of this study was to determine the role of HDAC2 in CS-induced skeletal muscle atrophy and senescence. Methods: Gastrocnemius muscle weight and cross-sectional area (CSA) were measured in mice with CS-induced emphysema, and changes in the expression of atrophy-related markers and senescence-related markers were detected. In addition, the relationship between HDAC2 expression and skeletal muscle atrophy and senescence was also investigated. Results: Mice exposed to CS for 24 weeks developed emphysema and gastrocnemius atrophy and exhibited a decrease in gastrocnemius weight and skeletal muscle cross-sectional area. In addition, the HDAC2 protein levels were significantly decreased while the levels of atrophy-associated markers, including MURF1 and MAFbx, and senescence-associated markers, including P53 and P21, were significantly increased in the gastrocnemius muscle. In vitro, the exposure of C2C12 cells to cigarette smoke extract (CSE) significantly increased the MAFbx and MURF1 protein levels and decreased the HDAC2 protein levels. Moreover, overexpression of HDAC2 significantly ameliorated CSE-induced atrophy and senescence and reversed the increased MURF1, MAFbx, P53, and P21 expression in C2C12 cells. In addition, CSE treatment significantly increased the IKK and NF-κB p65 protein levels, and PTDC (an NF-kB inhibitor) ameliorated atrophy and senescence. Conclusion: Our findings suggest that HDAC2 plays an important role in CS-induced skeletal muscle atrophy and senescence, possibly through the NF-κB pathway.