Exposure to fine particulate matter (PM2.5) represents a leading environmental cause of pulmonary inflammation and diseases, yet the underlying cellular mechanisms remain incompletely understood. Here, we identify histone deacetylase 10 (HDAC10) in macrophages as a critical regulator of PM2.5-induced airway inflammation by governing autophagic flux. PM2.5 exposure upregulated HDAC10 expression specifically in lung macrophages both in vivo and in vitro. Myeloid-specific Hdac10 deletion markedly attenuated PM2.5-induced airway inflammation and inflammatory cytokine production by inhibiting macrophage autophagy. Mechanistically, HDAC10 interacted with Beclin1 and deacetylated it at lysine 5 (K5), a modification critical for autophagic flux and subsequent inflammatory responses. Pharmacological inhibition of HDAC10 with salvianolic acid B reduced Beclin1 deacetylation, suppressed macrophage autophagy, and ameliorated PM2.5-induced lung inflammation. Clinically, elevated HDAC10 expression and reduced Beclin1 acetylation were observed in lung tissues from chronic obstructive pulmonary disease (COPD) patients, where HDAC10 mRNA levels correlated positively with the heightened lung inflammation. Our findings reveal a previously unrecognized HDAC10-Beclin1 axis that links PM2.5 exposure to macrophage autophagy and pulmonary inflammation, providing potential therapeutic targets for PM2.5-related respiratory diseases.

Introduction: Chronic obstructive pulmonary disease (COPD), an incurable chronic respiratory disease, has become a major public health problem. The relationship between the composition of intestinal microbiota and the important clinical factors affecting COPD remains unclear. This study aimed to identify specific intestinal microbiota with high clinical diagnostic value for COPD. Methods: The fecal microbiota of patients with COPD and healthy individuals were analyzed by 16S rDNA sequencing. Random forest classification was performed to analyze the different intestinal microbiota. Spearman correlation was conducted to analyze the correlation between different intestinal microbiota and clinical characteristics. A microbiota-disease network diagram was constructed using the gut MDisorder database to identify the possible pathogenesis of intestinal microorganisms affecting COPD, screen for potential treatment, and guide future research. Results: No significant difference in biodiversity was shown between the two groups but significant differences in microbial community structure. Fifteen genera of bacteria with large abundance differences were identified, including Bacteroides, Prevotella, Lachnospira, and Parabacteroides. Among them, the relative abundance of Lachnospira and Coprococcus was negatively related to the smoking index and positively related to lung function results. By contrast, the relative abundance of Parabacteroides was positively correlated with the smoking index and negatively correlated with lung function findings. Random forest classification showed that Lachnospira was the genus most capable of distinguishing between patients with COPD and healthy individuals suggesting it may be a potential biomarker of COPD. A Lachnospira disease network diagram suggested that Lachnospira decreased in some diseases, such as asthma, diabetes mellitus, and coronavirus disease 2019 (COVID-19), and increased in other diseases, such as irritable bowel syndrome, hypertension, and bovine lichen. Conclusion: The dominant intestinal microbiota with significant differences is related to the clinical characteristics of COPD, and the Lachnospira has the potential value to identify COPD.

Dysregulation of IL-17A is closely associated with airway inflammation and remodeling in severe asthma. However, the molecular mechanisms by which IL-17A is regulated remain unclear. Here we identify epithelial sirtuin 6 (SIRT6) as an epigenetic regulator that governs IL-17A pathogenicity in severe asthma. Mice with airway epithelial cell-specific deletion of Sirt6 are protected against allergen-induced airway inflammation and remodeling via inhibiting IL-17A-mediated inflammatory chemokines and mesenchymal reprogramming. Mechanistically, SIRT6 directly interacts with RORγt and mediates RORγt deacetylation at lysine 192 via its PPXY motifs. SIRT6 promotes RORγt recruitment to the IL-17A gene promoter and enhances its transcription. In severe asthma patients, high expression of SIRT6 positively correlates with airway remodeling and disease severity. SIRT6 inhibitor (OSS_128167) treatment significantly attenuates airway inflammation and remodeling in mice. Collectively, these results uncover a function for SIRT6 in regulating IL-17A pathogenicity in severe asthma, implicating SIRT6 as a potential therapeutic target for severe asthma.

In China, chronic obstructive pulmonary disease (COPD) was accounted for a quarter of the global COPD population and has become a large economic burden. However, the comprehensive picture of the COPD burden, which could inform health policy, is not readily available for all of the provinces of China. Here, we aimed to describe the burden of COPD in China, providing an up-to-date and comprehensive analysis at the national and provincial levels, and time trends from 1990 to 2019. Following the methodology framework and general analytical strategies used in the GBD 2019, we analyzed the incidence, prevalence, mortality, disability-adjusted life years (DALYs), years lived with disability (YLDs), and years with life lost (YLLs) attributable to COPD across China and the corresponding time trends from 1990 to 2019, stratified by age and province. In order to quantify the secular trends of the burden of COPD, the estimated annual percentage changes were calculated by the linear regression model of age-standardized rates (ASRs) and calendar years. We also presented the contribution of risk factors to COPD-related mortality and DALYs. The association between COPD burden and socio-demographic index (SDI) were also evaluated. From 1990 to 2019, the incidence and prevalence numbers of COPD increased by 61.2 and 67.8%, respectively, whereas the number of deaths and DALYs owing to COPD decreased. The ASRs of COPD burden, including incidence, prevalence, mortality, DALYs, YLDs, and YLLs continuously decreased from 1990 to 2019. The crude rates of COPD burden dramatically increased with age and reached a peak in the older than 95 years age group. In 2019, the leading risk factor for COPD mortality and DALYs was tobacco use in the whole population, but ambient particulate matter pollution was the most significant risk factor in females. At the provincial level, the ASRs of COPD burden was significantly associated with the SDIs, with the highest ASRs in the western provinces with low SDIs. Collectively, our study indicated that COPD remains an important public health problem in China. Geographically targeted considerations should be developed to enhance COPD health and reduce the COPD burden throughout China and in specific provinces.

目的 探讨大气细颗粒物(PM)增强香烟暴露小鼠炎症反应的机制.方法 用野生型(WT)及IL-17A基因敲除(IL-17A-/-)小鼠,按随机数字表法随机分为对照组、熏烟组、PM组、熏烟+PM组,每组6～8只.采用香烟烟雾暴露装置烟熏,气道滴注方法吸入PM,观察气道炎症反应,连续干预3个月后取检.用HE检测肺组织炎症浸润、用ELISA及RT-PCR检测肺组织炎症因子表达、免疫组化检测平滑肌表达、Masson染色观察胶原沉积及细胞流式检测分泌IL-17A的淋巴细胞类型.体外实验,用不同浓度的香烟提取物(CSE)和/或大气细微颗粒(PM)刺激人气道上皮(HBE)细胞,用IL-17A siRNA转染在HBE细胞中敲除IL-17A基因,用RT-PCR检测炎症因子表达.结果 与对照组、熏烟组及PM组比较,熏烟联合PM组小鼠肺组织炎症因子(CXCL1、TFG-β1、IL-6及IL-17A)、胶原沉积及平滑肌表达明显增高.相反,IL-17A-/-小鼠能缓解上述指标.流式细胞检测发现PM主要通过调控CD4+细胞促进IL-17A表达,增强熏烟诱导的炎症反应.在体外,CSE、PM分别干预HBE细胞均能诱导IL-6、IL-8表达,而CSE联合PM干预HBE细胞能进一步增加IL-6、IL-8表达.敲除HBE细胞IL-17A基因后,能缓解IL-6、IL-8表达.结论 PM能诱导IL-17A表达,加剧熏烟小鼠肺组织的炎症反应、胶原沉积及平滑肌增生,提示针对IL-17A信号通路靶向治疗可能对缓解PM导致的慢性阻塞性肺疾病急性加重有效.

Background We have reported that heparin-binding epidermal growth factor (HB-EGF) is increased in patients with chronic obstructive pulmonary disease (COPD) and associated with collagen deposition, but the mechanisms remain unclear. In the present study, we aimed to investigated the inflammatory cytokines secreted by bronchial epithelial cells following exposure to HB-EGF that promoted proliferation and migration of human lung fibroblast. Methods HB-EGF-induced inflammatory cytokines were assayed in two airway epithelial cells (primary human bronchial epithelial cells [HBECs] and BEAS-2B cells). Moreover, the culture supernatants derived from HB-EGF-treated HBECs and BEAS-2B cells were added to human primary lung fibroblasts. The effect of culture supernatants on proliferation and migration of fibroblasts was assessed. Results IL-8 expression was significantly increased in bronchial epithelial cells treated with HB-EGF, which was at least partially dependent on NF-kB pathways activation. HB-EGF-induced IL-8 was found to further promote lung fibroblasts proliferation and migration, and the effects were attenuated after neutralizing IL-8. Conclusions These findings suggest that HB-EGF may be involved in the pathology of airway fibrosis by induction of IL-8 from airway epithelium, subsequently causing lung fibroblasts proliferation and migration. Thus, inhibition of HBEGF and/or IL-8 production could prevent the development of airway fibrosis by modulating fibroblast activation.