American journal of physiology. Lung cellular and molecular physiology最新文献

The airway epithelium, a primary target for viral infection, plays a critical role in disease response-particularly in individuals with preexisting airway conditions such as cystic fibrosis (CF). At the onset of the SARS-CoV-2 pandemic, individuals with CF were expected to have severe outcomes based on earlier viral outbreaks; however, those on effective CF transmembrane conductance regulator (CFTR) modulators showed milder disease. Patients with CF on the CFTR modulator combination elexacaftor/tezacaftor/ivacaftor (ETI) combination therapy showed attenuated viral infection and reduced airway epithelial damage. To investigate how this is accomplished, we used an induced pluripotent stem cells (iPSC)-derived airway epithelium model of CF and syngeneic CFTR-corrected cells to examine responses to SARS-CoV-2 infection. CF iPSC-airways were significantly more susceptible to viral infection and epithelial injury compared with their corrected counterparts, despite comparable expression of viral entry factors. Strikingly, pretreatment with ETI conferred significant protection in CFTR-corrected and non-CF, wild-type (WT) airway epithelia, as well as in iPSC-derived and primary epithelia. Single-cell RNA sequencing analysis confirmed a heightened infection and proinflammatory response in CF iPSC-airways, whereas ETI treatment significantly reduced these responses in both CF and CFTR-corrected iPSC-airways. Mechanistically, ETI treatment led to increased type I interferon signaling and induction of antiviral genes, whereas expression of many other proinflammatory genes was suppressed in both CF and non-CF iPSC-airways. These results underscore the therapeutic promise of CFTR-modulators such as ETI in mitigating SARS-CoV-2 infection and inflammation, not only in CF airways but also in non-CF airways, highlighting the broad applicability of CFTR-modulators as a therapeutic strategy in viral pneumonia and inflammatory lung disease.NEW & NOTEWORTHY Using rigorously controlled iPSC-derived airway models, the study shows that CFTR-deficient cells are more vulnerable to SARS-CoV-2 and display stronger inflammation than syngeneic CFTR-corrected controls. The CFTR modulator ETI reduces viral injury and boosts antiviral pathways in both CF and non-CF cells. Even at baseline, CFTR modulation enhances antiviral responses and lowers inflammation. Overall, the findings reveal a broad protective antiviral effect of CFTR modulators and highlight their therapeutic promise in inflammatory lung disease.

Background: Alveolar macrophages (AMs) play a key role in the innate immune system and the pathogenesis of bronchopulmonary dysplasia (BPD), a condition with a significant sex bias. However, the influence of biological sex on AM immunometabolism remains poorly defined. Objective: We tested the hypothesis that female AMs would exhibit greater metabolic resilience (less impact on their mitochondrial function) compared to male AMs upon exposure to hyperoxia. Methods: We characterized bioenergetic profiles of male (MH-S) and female (AMJ2-C11) adult murine AM cell lines and primary neonatal AMs from C57BL/6 pups. Oxygen consumption (OCR) and extracellular acidification rates (ECAR) were quantified using Seahorse extracellular flux analysis at baseline and following 48 hours of hyperoxia (85% O₂). Results: Adult female AMs displayed an elevated basal and maximal respiration compared to males. Upon exposure to hyperoxia, female AMs showed decreased maximal OCR and spare respiratory capacity. Conversely, male AMs showed little change in oxidative phosphorylation. Uniquely, neonatal AMs of both sexes show a suppression in their mitochondrial function upon exposure to hyperoxia, but the decline is more significant in the male macrophages. In addition, the neonatal female macrophages also showed a higher glycolytic reserve compared to their baseline in room air, upon exposure to hyperoxia. Conclusions: Biological sex and developmental stage are fundamental determinants of AM bioenergetics. These intrinsic sex-specific mechanisms may underlie differential susceptibility to neonatal lung injury, underscoring the necessity of sex-specific therapeutic strategies.

With the rising prevalence of vaping, there is a pressing need to identify biomarkers of toxicity related to chronic effects induced by the inhalation of electronic nicotine delivery system (ENDS) aerosols. In a mouse model, we investigated the long-term pulmonary effects associated with exposures to cinnamon-flavored ENDS aerosols for up to 6 months. Following exposures and after 2-month of recovery, pulmonary function testing and lung biochemical responses were assessed. Despite similar serum cotinine concentrations in male and female mice, males exposed for 6 months to ENDS aerosols exhibited significant reductions in tidal and minute volumes, breathing frequency and elevated respiratory elastance, while significantly increased tissue damping and respiratory resistance were observed in both sexes. All parameters, except minute volume and breathing frequency in males, returned to baseline following recovery. Although there were no significant changes in pulmonary inflammation in all groups, lung RNA sequencing revealed significant up-regulation of Cxcl5, a neutrophil chemotactic chemokine, in all groups exposed to ENDS aerosols. In total, 69 genes in males and 63 genes in females, were dysregulated, including up-regulated pro-inflammatory and oxidative stress-related genes. HIF-1 in lung tissue, and CXCL5 serum concentrations, were significantly elevated in the ENDS and recovery groups, respectively, compared to controls. Overall, this study showed that pulmonary inflammation is not a hallmark of long-term ENDS aerosol exposure, whereas altered lung function is a sensitive indicator of lung damage in mice.

Integrin signaling promotes cellular proliferation, inflammation, and fibrosis in various forms of lung diseases, including pulmonary fibrosis, asthma, and acute respiratory distress syndrome. Recent studies suggest the promising role of integrins in the pathogenesis of pulmonary arterial hypertension, a morbid and incurable disease. In this review, we explore the biologic basis of integrins in potentiating pulmonary vascular disease and their candidacy as treatment targets. Specifically, we explore integrin-derived effects implicated in the pathobiology of pulmonary vascular disease, such as TGF-β activation, neointima formation, and inflammatory cell recruitment. We discuss intracellular pathways involving cytoplasmic kinases and matrisomal integrin ligands that are studied in the specific context of pulmonary vascular disease, focusing on recent therapeutic animal studies targeting integrin biology. Finally, we summarize unanswered knowledge gaps in the pursuit of therapeutic translation of integrin modulation.

Congenital diaphragmatic hernia (CDH) is a common and severe structural malformation in which the high rate of morbidity and mortality is caused by lung hypoplasia and pulmonary hypertension. Severity of lung and pulmonary vascular defects in patients with CDH is heterogeneous with both intrinsic defects during development and mechanical compression playing important roles. Genetic variants have been identified in 30% of CDH patients and are associated with increased morbidity and mortality but it is unclear how these variants impact lung and pulmonary vascular defect severity. Deletions of 8p23.1 account for 3-5% of cases and encompass GATA4, a transcription factor that directs gene expression throughout the developing embryo. CDH patients with GATA4 haploinsufficiency have high mortality and severe lung hypoplasia and pulmonary hypertension. Given this information, our aim was to characterize the role of GATA4 during lung and pulmonary vascular development. We generated mice with lung-specific deletion of Gata4 and found that GATA4 is not required during lung or pulmonary vascular development. However, mice with diaphragm-specific inactivation of Gata4 die after birth with abnormal diaphragm formation and lung hypoplasia. Mechanical compression of the embryonic lungs was associated with abnormal gene expression and increased phosphorylation of mechanosensory protein YAP1 resulting in decreased cell cycling. Our data suggest that the lung and pulmonary vascular phenotype of patients with CDH and GATA4 haploinsufficiency is due to mechanical compression. Strategies that promote lung growth prior to delivery such as fetal tracheal occlusion may be beneficial in these patients.

Inhalation of cigarette smoke (CS) is the primary risk factor for COPD, inducing epigenetic changes in the airway epithelium, including dysregulation of long-noncoding RNAs (lncRNAs). LncRNA HOTAIR (Homeobox gene Transcript Antisense RNA) regulates chromatin remodeling and has been implicated in CS-induced malignant transformation. We hypothesized that HOTAIR expression is altered in COPD, leading to airway epithelial abnormalities. HOTAIR expression and overall survival were studied in The Cancer Genome Atlas (TCGA) database. Airway epithelial cells (AECs) were isolated from transplanted lungs of 11 COPD patients, tracheobronchial tissue of 9 non-COPD donors and bronchial brushings of ex-smokers with/without COPD (n=6/group). HOTAIR expression, histone modifications and production of pro-inflammatory cytokines (CXCL8 and GM-CSF) were assessed in the absence/presence of CS extract (CSE) and HOTAIR-polycomb inhibitor AQB. High HOTAIR expression correlated with poor overall survival in cancer patients with COPD, but not those without. While HOTAIR expression was not significantly different between AECs from control and COPD subjects at baseline, it was significantly increased by 20% CSE only in COPD-derived AECs. CSE significantly decreased H3K4me3 levels in COPD-derived AECs, but not those from controls. AQB reduced baseline H3K27me3 levels in both groups, with a stronger effect in control-derived AECs. Additionally, it reduced H3K4me3 levels in the presence of CSE in both groups. Finally, while AQB significantly suppressed CSE-induced production of GM-CSF and CXCL8 in control AECs, it failed to do so in COPD. Together, these findings suggest that COPD-derived AECs are more susceptible to CSE-induced HOTAIR upregulation, which may have a pro-inflammatory effect that cannot be inhibited by AQB.

Early airflow changes associated with tobacco smoking often occur without observable obstruction or symptoms. Spirometry, the gold standard, has limitations in detecting early disease highlighting the need for sensitive diagnostic methods. We aimed to evaluate the utility of the forced oscillation technique (FOT) and biomarkers in detecting early airway abnormalities in smokers and patients with chronic obstructive pulmonary disease (COPD), and to explore the correlation between FOT parameters, spirometry measures, and biomarkers of airway inflammation. A cross-sectional study was conducted on 71 participants divided into three groups: patients with COPD (CP, n = 27), normal lung function smokers (NS, n = 22), and healthy controls (HC, n = 22). Lung function was assessed using spirometry and FOT, with biomarkers of inflammation (MMP-9, TIMP-1, and TIMP-2) measured from venous blood samples. Statistical analyses included group comparisons and correlation between lung function parameters and biomarker levels. Patients with COPD had significantly lower spirometry and higher FOT values compared with NS and HC (P < 0.01). In contrast, NS participants had similar spirometry values to HC, except for FEF25-75% and peak expiratory flow (PEF). The NS group exhibited significantly higher values for R5 compared with HC (P < 0.05). FOT parameters, particularly R5, demonstrated comparable diagnostic accuracy with spirometry in smokers, and all other parameters showed excellent discriminatory ability in patients with COPD. MMP-9 correlated positively with percentage predicted FOT parameters, R5-R20 and AX, and X5 (r' = 0.29, 0.30, and 0.31; P = 0.02, 0.04, and 0.02, respectively) in the combined group of smokers and patients with COPD and positively with percentage predicted Fres (r' = 0.30; P = 0.01) when all groups were analyzed together. FOT may be a sensitive and complementary measure to detect early airway changes in smokers and patients with COPD. MMP-9 correlating with FOT further supports the role of FOT combined with biomarkers in detecting early airway abnormalities in smokers and earlier stages of COPD.NEW & NOTEWORTHY This study highlights the utility of the forced oscillation technique (FOT) and biomarkers in detecting early airway changes in smokers and patients with COPD. FOT, along with biomarkers for airway remodeling can provide a sensitive measure and insight into early airway dysfunction, complementing traditional spirometry. These findings underscore the importance of early detection of airway abnormalities and the potential of FOT as a clinical tool for managing at-risk populations.

As bioactive microproteins, mitochondrial-derived microproteins (MDPs) are encoded within the small open reading frames of mitochondrial DNA. MDPs have been shown to be altered in a number of disease states and have mitochondrial, nuclear, and extracellular actions. Most published work on MDPs has focused on MOTS-c and Humanin's actions in tissues with high mitochondrial density (heart, skeletal muscle, and brain) or in disease states of advanced age-Alzheimer's, cancer, and cardiovascular disease. This review aims to highlight the existing gaps in knowledge related to MDPs' role in lung homeostasis and disease-including acute lung injury, chronic obstructive pulmonary disease, allergic asthma, and pulmonary fibrosis. The increasingly recognized role of MDPs in nonpulmonary diseases sheds light on the importance of more investigations of MDPs, their clinical and mechanistic roles, and their therapeutic potential for pulmonary diseases.