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

In this research, we delve into the association between epigenetic aging and idiopathic pulmonary fibrosis (IPF), a debilitating lung disease that progresses over time. Utilizing the Illumina MethylationEPIC array, we assessed DNA methylation levels in donated human lung tissue from IPF patients, categorizing the disease into mild, moderate, and severe stages based on clinical assessments. We employed seven epigenetic clocks to determine age acceleration, which is the discrepancy between biological (epigenetic) and chronological age. Our findings revealed a notable acceleration of biological aging in IPF tissues compared to healthy controls, with four clocks-Horvath's, Hannum's, PhenoAge, and DunedinPACE-showing significant correlations. DunedinPACE, in particular, indicated a more rapid aging process in the more severe regions within the lungs of IPF cases. These results suggest that the biological aging process in IPF is expedited and closely tied to the severity of the disease. The study underscores the potential of DNA methylation as a biomarker for IPF, providing valuable insights into the underlying methylation patterns and the dynamics of epigenetic aging in affected lung tissue. This research supports the broader application of epigenetic clocks in clinical prognosis and highlights the critical role of biological age in the context of medical research and healthcare.

When pulmonary surfactant was first detected in the 1950s by Pattle and Clements, many thousands of infants perished each year due to a respiratory illness termed Hyaline Membrane Disease. Hyaline membranes are formed by plasma leaking through damaged endothelial barriers into the terminal bronchiolar: alveolar spaces. Since the leaking plasma lacks erythrocytes, these clots are opaque. Insightful research by Avery and Mead soon led to the suggestion that the neonatal Respiratory Distress Syndrome (RDS) did not arise because of the presence of hyaline membranes, but rather was related to the lack of sufficient pulmonary surfactant, mainly as a result of immaturity. Unfortunately, initial attempts at treating RDS with aerosolized dipalmitoyl-phosphatidylcholine, the major single molecular component, proved unsuccessful. Almost 20 years later it was demonstrated by Enhorning and Robertson that treating prematurely delivered rabbit pups with natural surfactant prevents respiratory failure. Initially, it appeared unlikely that animal surfactants could be used for therapy with human infants. However, in 1980, Fujiwara demonstrated that a modified bovine surfactant promoted gaseous exchange with infants suffering from RDS. Soon a number of bovine and porcine modified surfactants and two wholly synthetic formulations were shown to alleviate RDS. The present review relates some of the key scientific findings and significant clinical contributions responsible for reducing the neonatal morbidity and mortality associated with RDS. It further describes some of the more recent findings on the biological, biophysical and physiological significance of pulmonary surfactant in health and disease.

Recent studies have linked deficiencies in β-carotene ingestion and its metabolites with an increased risk and severity of asthma exacerbations. We demonstrate that β-ionone, a β-carotene metabolite, dose-dependently relaxes upper and lower airways in vitro using wire myography of tracheal rings and phase-contrast microscopy of precision-cut lung slices (PCLSs). We demonstrate that β-ionone-induced relaxation is mediated through extraocular opsin-3 (OPN3) receptor activation via pharmacological competitive inhibition with chromophore 9-cis retinal, and through the decreased relaxation demonstrated in Opn3-null PCLSs. We implicate a mechanistic pathway suggestive of G_ɑs activation that is in agreement with our previous findings. Lastly, we confirmed OPN3 expression in airway smooth muscle cells by immunofluorescence and mRNA expression. Our findings implicate β-ionone as a potential therapeutic agent for conditions characterized by bronchoconstriction, such as asthma and COPD. Moreover, this study underscores the significance of dietary intake, particularly of β-carotene rich foods, in maintaining respiratory health.

Neonatal acute respiratory distress syndrome (NARDS) is a severe and potentially life-threatening form of lung injury recently defined by the International Neonatal ARDS Consensus. It is marked by extensive lung inflammation and damage to the alveolar epithelium and vascular endothelium. NARDS can be triggered by direct inflammatory exposures, such as pneumonia and aspiration, and indirect exposures, including sepsis, necrotizing enterocolitis, and chorioamnionitis. This review provides clinicians and researchers with the latest insights on NARDS. We adopt a cross-disciplinary approach to discuss the diagnostic criteria, pathobiology, triggers, epidemiology, and treatments of NARDS. Additionally, we summarize existing clinical studies and advanced preclinical models that help address current knowledge gaps. Future research should focus on standardizing the Montreux consensus definition of NARDS in preclinical and clinical studies, identifying biomarkers, developing prediction models, and exploring novel therapies for affected infants.

Lung vessel remodeling leads to increased pulmonary vascular resistance, causing pulmonary arterial hypertension (PAH), and consequently right ventricular hypertrophy and failure. In patients suffering from systemic sclerosis (SSc), PAH can occur and is a life-threatening complication. Dysregulation of immune processes plays a crucial role in pulmonary vascular remodeling, as has previously been shown in Fos-related antigen-2 (Fra-2) transgenic (TG) mice, a model of SSc-PAH. Here, we investigate whether vascular remodeling in the Fra-2 TG model is driven by type 2 inflammation and is associated with vascular hyperresponsiveness, an important feature of PAH pathobiology. Basal pulmonary arterial pressure and pulmonary vascular responsiveness to hypoxic ventilation and serotonin were increased in isolated, perfused and ventilated lungs of Fra-2 TG mice compared to wild-type (WT) littermates. Similarly, contractile responses of isolated intrapulmonary arteries were elevated in Fra-2 TG mice. We also observed increased expression of contractile genes in Fra-2 overexpressing human pulmonary artery smooth muscle cells (PASMCs) with elevated intracellular calcium levels after IL-13 stimulation. These findings were corroborated by transcriptomic data highlighting dysregulation of vascular smooth muscle cell contraction and type 2 inflammation in Fra-2 TG mice. In vivo, type 2-specific anti-inflammatory treatment with IL-13 neutralizing antibodies improved vascular remodeling in Fra-2 TG mice, similar to corticosteroid treatment with budesonide. Our results underscore the importance of type 2 inflammation and its potential therapeutic value in PAH-associated pulmonary vascular remodeling and hyperresponsiveness in SSc-PAH.

Prenatal cannabis use is rising, in part due to legalization and perceptions of safety. The impact of prenatal cannabis exposure on offspring development, especially respiratory health, remains largely unknown. The objective of this study was to determine whether in utero exposure to delta-9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis, is deleterious to offspring lung development and function using a rhesus macaque model. Female rhesus macaques received a daily edible containing either THC (2.5mg/7kg/day, equivalent to a heavy medical cannabis dose) or placebo during gestation and postnatally. Serial in utero magnetic resonance imaging (MRI) was performed during pregnancy at approximately G110 and G150. At 6 months of age infants underwent pulmonary function testing, followed by tissue collection for molecular analysis (bulk-RNAseq, whole genome bisulfite sequencing, and spatial-RNAseq). THC exposed infants displayed significantly reduced forced residual capacity (FRC) which correlated with non-significant decreases in total lung capacity (TLC), lung diffusion capacity (DLCO) and lower fetal lung perfusion, oxygen availability, and lung volume measured by MRI. Consistent with these decreases in volume indices, levels of pulmonary growth factors were decreased in bronchial alveolar lavage at 6 months. Molecular analysis of infant lungs revealed altered epigenetic regulation of gene expression, including at genes involved in extracellular matrix organization and lung development, and activation of immune signaling. Our study suggests that exposure to edible prenatal THC alters epigenetic regulation of lung gene expression and may negatively affect offspring lung development and function. Data from this study will help guide healthcare provider counseling on cannabis use in pregnancy.

Rigor and reproducibility are vital to scientific advancement. It is unclear whether a protocol optimized for tissue dissociation in one institution performs well universally. Here, we share our brand-new lab's experience with interinstitutional variability that led to the discovery that a protocol optimized for murine lung dissociation at Boston University (BU) fails to reproduce similar CD4⁺ T cell, CD8⁺ T cell, and B cell outcomes at the University of Michigan at Ann Arbor (U-M). We report that the type 2 collagenase-based protocol from BU yields reduced numbers of lung lymphocytes at U-M, and this appeared to be a result of harsher collagenase activity despite using identical protocols, reagents, and vendors at both institutions. This variability could not be explained by higher Ca²⁺ levels in Ann Arbor water (which we posited may heighten the collagenase activity) but instead appeared to be due to technical details within the protocol that led to the protocols behaving in an institution-specific manner. Indeed, we find that merely switching between the protocol from BU and a newly optimized protocol at U-M was sufficient to improve (or worsen) lymphocyte yields from murine lungs when synchronously performed at both institutions. Taken together, although the reason(s) for the interinstitutional variability in lymphocyte outcomes remains unknown, this report serves as a cautionary tale against directly adopting lung dissociation protocols across institutions without reoptimization, and calls for careful inspection of cross-institutional reproducibility of previously described protocols.NEW & NOTEWORTHY Rigor and reproducibility are vital to scientific advancement. It is unclear whether a protocol optimized for tissue dissociation in one institution performs well universally. Here, the authors share their experience with interinstitutional variability that led to the discovery that a protocol optimized for murine lung dissociation in one institution failed to reproduce similar lymphocyte outcomes elsewhere. This report, thus, serves as a cautionary tale against directly adopting tissue dissociation protocols across institutions without reoptimization.

Severe vitamin D (vitD) deficiency is a very common condition in patients with pulmonary arterial hypertension (PAH), and it is a predictor of poor prognosis. There is emerging evidence suggesting a connection between the insufficient response to phosphodiesterase-5 inhibitors (PDE5i) and vitD deficiency in patients with PAH. In the present translational study, vitD deficiency was induced in Wistar rats by exposure to vitD-free diet for 5 wk and followed by Su5416 administration and hypoxia (10%) for 3 wk, a standard experimental model of PAH. Then, rats were randomized to either 1) the PDE5i tadalafil and continuing vitD-free diet or 2) tadalafil plus a single dose of vitD and standard diet for 4 wk. VitD supplementation improved exercise capacity and right ventricular function and decreased systolic right ventricular pressure, right atrial hypertrophy, right ventricular hypertrophy, and pulmonary arterial remodeling. VitD improved the ex vivo endothelium-dependent response to acetylcholine, indicating an improvement in NO bioavailability, which also resulted in an acute ex vivo response to sildenafil. Thus, the restoration of vitD, by rescuing endothelial function and PDE5i effectiveness, significantly improved the histological, hemodynamic, and functional features of rats with PAH. VitD may be especially beneficial for PDE5i-treated patients with PAH.NEW & NOTEWORTHY Severe vitamin D deficiency is very prevalent in patients with pulmonary arterial hypertension. We show that addition of vitamin D to the standard PDE5 inhibitor tadalafil increases its therapeutic efficacy in pulmonary hypertensive rats that were deficient in vitamin D.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by obstructed airflow, airway remodeling, and inflammation, with cigarette smoke (CS) exposure being the main risk factor. Although CS extract (CSE) has been shown to activate caspases in various cell types, the role of caspases in human lung fibroblasts (hLFs) in COPD remains poorly understood. Recent studies have linked caspases to extracellular matrix (ECM) remodeling in skin and kidney fibrosis. Caspase activation can be triggered by oxidative stress, with active caspase-3 executing the pore-forming protein gasdermin E (GSDME) in the cleaved N-terminal form GSDME-NT. We investigated whether CSE activates caspases and GSDME in hLFs and their role in ECM remodeling. MRC-5 lung fibroblasts were treated with CSE with or without the antioxidant N-acetyl-cysteine (NAC) and the caspase-8 inhibitor z-IETD-fmk. We measured the effects on caspase-1-8-3/7 activation, GSDME cleavage, ECM remodeling (procollagen Iα1, COLIα1, and fibronectin, FN), and mitochondrial superoxide (mSOX) generation. Key findings were validated in patient-derived hLFs (phLFs). Our results showed that CSE induced caspase-1-8-3/7 activation, mSOX generation, and decreased COLIα1 and FN levels in MRC-5. CSE caused caspase-8-dependent activation of caspase-3, leading to GSDME cleavage. Treatment with NAC inhibited mSOX and caspase activation. Inhibition of caspase-8 and mSOX restored FN and COLIα1 levels. In phLFs, we confirmed caspase-1 and -8 activation, mSOX increase, COLIα1/FN decrease, and the effects of NAC. Our findings highlight the role of the axis caspase-8-3/7-GSDME and mSOX in regulating ECM protein, suggesting that these pathways may contribute to remodeling in COPD.NEW & NOTEWORTHY This research investigates the connection between caspases, gasdermins, and extracellular matrix (ECM) remodeling in the context of cigarette smoke-associated lung diseases. The study found that cigarette smoke extract (CSE) activates caspases and gasdermin E in human lung fibroblasts, leading to decreased ECM protein expression and release. Findings herein reported suggest that targeting the caspase-8-3/7-gasdermin axis and mitochondrial reactive oxygen species may help restore ECM remodeling in chronic lung diseases associated with cigarette smoke exposure.

Acute exposure to ozone (O₃) causes upper and lower airway inflammation. We and others have previously demonstrated that O₃ oxidizes lipids, particularly cholesterol, into electrophilic oxysterols, such as secosterol B (SecoB), which can adduct proteins, thus altering cellular signaling pathways. To investigate how O₃-derived oxysterols influence cytokine and chemokine release, nasal epithelial cells (HNECs) from healthy donors (n = 18 donors) were exposed to 0.4 ppm O₃ for 4 h. Afterward, immune mediators in apical washes and basolateral supernatants were analyzed using ELISAs, whereas sterol and oxysterol levels were examined using liquid-chromatography mass spectrometry (LC-MS). O₃ exposure increased SecoB, 7-ketocholesterol (7Keto-Chol), 27-hydroxycholesterol (27OH-Chol), and epoxycholesterols in a sex-dependent manner. Female-derived HNECs had significant increases in SecoB, 27OH-Chol, and β-epoxycholesterol, whereas male-derived cells showed increases in 7Keto-Chol only. O₃ decreased the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-7 but increased interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), VEGF, and Eotaxin. Females exhibited O₃-induced IL-1β and VEGF increases, whereas males showed increased Eotaxin and reduced GM-CSF. Basolaterally, O₃ exposure decreased GM-CSF and thymus and activation-regulated chemokine (TARC) while raising IL-6, IL-13, IL-1β, IL-8, and TNFα. Females showed higher TNFα and IL-1β, but males did not. Oxysterols correlated differently with cytokines by sex. Females showed positive correlations between oxysterols and proinflammatory cytokines like IL-6 and IL-1β, whereas males displayed negative correlations with IL-6, IL-8, and TNFα. In conclusion, O₃-induced cytokine/chemokine responses and sterol/oxysterol levels in HNECs vary by sex, with donor-specific oxysterols associated with O₃-triggered inflammatory mediator release.NEW & NOTEWORTHY It is increasingly recognized that lung biology and responses to pollutant exposures differ in males and females. Using a model of differentiated nasal epithelial cells from male and female donors, our data demonstrate that pollutant-induced cytokine/chemokine responses and oxidized lipid levels vary by sex, with donor-specific oxidized lipids linked to inflammatory mediator release.