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

Bronchopulmonary dysplasia (BPD) is a neonatal lung disease characterized by inflammation and scarring leading to long-term tissue damage. Previous whole tissue proteomics identified BPD-specific proteome changes and cell type shifts. Little is known about the proteome-level changes within specific cell populations in disease. Here, we sorted epithelial (EPI) and endothelial (ENDO) cell populations based on their differential surface markers from normal and BPD human lungs. Using a low-input compatible sample preparation method (MicroPOT), proteins were extracted and digested into peptides and subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteome analysis. Of the 4,970 proteins detected, 293 were modulated in abundance or detection in the EPI population and 422 were modulated in ENDO cells. Modulation of proteins associated with actin-cytoskeletal function, such as SCEL, LMO7, and TBA1B was observed in the BPD EPIs. Using confocal imaging and analysis, we validated the presence of aberrant multilayer-like structures comprising SCEL and LMO7, known to be associated with epidermal cornification, in the human BPD lung. This is the first report of the accumulation of cornification-associated proteins in BPD. Their localization in the alveolar parenchyma, primarily associated with alveolar type 1 (AT1) cells, suggests a role in the BPD postinjury response. In the ENDOs, redox balance and mitochondrial function pathways were modulated. Alternative mRNA splicing and cell proliferative functions were elevated in both populations, suggesting potential dysregulation of cell progenitor fate. This study characterized the proteome of epithelial and endothelial cells from the BPD lung for the first time, identifying population-specific changes in BPD pathogenesis.NEW & NOTEWORTHY The study is the first to perform proteomics on sorted pulmonary epithelial and endothelial populations from bronchopulmonary dysplasia (BPD) and age-matched control human donors. We identified an increase in cornification-associated proteins in BPD (e.g., SCEL and LMO7), and evidenced the presence of multilayered structures unique to BPD alveolar regions, associated with alveolar type 1 (AT1) cells. By changing the nature and/or biomechanical properties of the epithelium, these structures may alter the behavior of other alveolar cell types potentially contributing to the arrested alveolarization observed in BPD. Finally, our data suggest the modulation of cell proliferation and redox homeostasis in BPD providing potential mechanisms for the reduced vascular growth associated with BPD.

Cadmium (Cd), a toxic heavy metal found in air pollution, poses serious risks to lung health due to its efficient pulmonary absorption and prolonged biological half-life. This study examines how ad libitum (AL), time-restricted feeding (TRF), and intermittent fasting (IF) influence Cd-induced lung injury and immune responses in mice. Adult male C57BL/6 mice were preacclimated to AL, TRF, or IF regimens for 3 wk, followed by intratracheal exposure to cadmium chloride (CdCl₂; 0.5 mg/kg). Lung mechanics were assessed using flexiVent, bronchoalveolar lavage (BAL) fluid was analyzed for inflammation, and immune profiling was performed on spleens and mediastinal lymph nodes (MLNs) 14 days postexposure. Cd exposure increased immune cell infiltration in BAL fluid. IF mice showed significantly elevated inflammatory cytokines, while TRF mice had a modest increase. Histological analysis revealed greater lung inflammation in TRF mice, whereas lung mechanics were more impaired in IF mice, suggesting distinct injury profiles. Immune profiling showed that IF reduced activated and effector T-cell populations in the spleen but increased them in MLNs, indicating a shift in immune localization. Furthermore, compared to the AL, Cd-exposed IF mice had minimal changes in T-cell distribution but reduced effector CD4⁺ and CD8⁺ T-cells in the spleen and an increase in MLNs. In contrast, TRF mice exhibited minimal changes in T-cell distribution. These findings suggest that dietary regimens modulate immune responses and lung injury following Cd exposure. Feeding patterns play a critical role in shaping susceptibility to environmental toxicants and should be considered in future toxicological and immunological studies.NEW & NOTEWORTHY This study reveals that time-restricted feeding (TRF) and intermittent fasting (IF) distinctly modulate cadmium-induced lung injury and immune responses in mice. TRF worsened lung inflammation, while IF impaired lung function and altered immune cell distribution, indicating divergent mechanisms. These findings highlight how feeding patterns influence pulmonary responses to environmental toxicants and suggest that metabolic rhythms may shape airway immunity, offering new insight into dietary modulation as a potential strategy in lung injury management.

Ozone exposure increases the risk of infection, worsens lung diseases, and causes systemic health issues. As ambient ozone levels continue to rise globally, effective interventions are needed to reduce these harmful effects. Vitamin D, known for its anti-inflammatory properties, has been inversely linked to various lung conditions, including ozone-induced airway inflammation and reduced lung function. However, oral vitamin D supplementation has shown inconsistent results, possibly due to poor delivery to lung tissues. This study explores a novel approach using vitamin D aerosols to counter ozone-induced damage in primary human bronchial epithelial cells. Cells were pretreated with vitamin D aerosols apically or as a bulk addition basolaterally before ozone exposure at the air-liquid interface. Both treatment routes significantly reduced the ozone-induced secretion of the inflammatory cytokine IL-8. Furthermore, vitamin D suppressed the ozone-induced expression of inflammation- and oxidative stress-related genes, including CXCL8, FFAR2, PTGS2 (COX-2), and NFKB2. Gene set enrichment analysis indicated that vitamin D reversed ozone-driven pathways related to inflammation, oxidative stress, and immune dysfunction. In addition, vitamin D pretreatment reduced lipid peroxidation, glutathione oxidation, and formation of ozone-derived oxysterols, suggesting a membrane antioxidant effect. These findings support vitamin D's potential as a protective agent against inhaled oxidants and highlight inhaled delivery as a promising therapeutic strategy for treating lung diseases.NEW & NOTEWORTHY Vitamin D aerosols have the potential to protect against exposure to ozone and other inhaled oxidants and prevent the development and exacerbation of lung disease. Here, we show that aerosolized vitamin D treatment decreased ozone-induced oxidative stress and inflammatory responses, as well as decreased production of an oxysterol, β-epoxycholesterol, indicating vitamin D may act as a membrane antioxidant in the airway epithelium.

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by progressive and irreversible loss of lung function. CSP7 exerts antifibrotic effects on fibrotic lung (myo)fibroblasts, which are the primary effector cells in progressive pulmonary fibrosis (PF) via restoring p53-microRNA-34a-feedback induction. However, p53-microRNA-34a's role in the antifibrotic effects of nintedanib and pirfenidone has not been explored. We compared the effects of oral-gavage-fed standard-of-care antifibrotic drugs, nintedanib or pirfenidone, with CSP7 administered by intraperitoneal injection or via airway by dry powder inhalation against bleomycin-induced PF using wild type, p53 flox (p53^fl/fl), microRNA-34a flox (microRNA-34a^fl/fl), and tamoxifen inducible conditional knockout mice lacking p53 (p53^cKO) or microRNA-34a (miR-34a^cKO) expression in lung fibroblasts. Compared with wild type or p53^fl/fl or microRNA-34a^fl/fl mice, p53^cKO and miR-34a^cKO mice exhibited more severe post-bleomycin body weight and lung function loss, lower survival, and more extracellular matrix deposition. Although daily treatment of wild-type mice with CSP7 or with nintedanib or pirfenidone between days 14 and 21 post-bleomycin improved survival, body weight and lung function, combination of CSP7 with nintedanib or pirfenidone was more effective than either drug. Interestingly, p53^cKO- and miR-34a^cKO-PF mice resisted these treatments, supporting the importance of restoration of p53-miR-34a-feedback induction in lung (myo)fibroblasts for the antifibrotic effects.NEW & NOTEWORTHY Pulmonary fibrosis is a progressive and fatal fibroproliferative disease. The current drugs (nintedanib/pirfenidone) only slow clinical progression. Myofibroblasts are the primary effector cells of PF. We found that CSP7, nintedanib and pirfenidone exert antifibrotic effects through restoring p53-microRNA-34a feedback induction in lung (myo)fibroblasts. We further found that daily treatment of mice with CSP7/nintedanib/pirfenidone between days 14 and 21 post-bleomycin lung fibrosis improve survival, body weight and lung function, and combination therapy had added benefit.

Cystic fibrosis (CF) is a multiorgan disease caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene, leading to chronic pulmonary infections and hyperinflammation. Among pathogens colonizing the CF lung, Pseudomonas aeruginosa is predominant, infecting over 50% of adults with CF, and becoming antibiotic-resistant over time. Current therapies for CF, while providing tremendous benefits, fail to eliminate persistent bacterial infections, chronic inflammation, and irreversible lung damage, necessitating novel therapeutic strategies. Our group engineered mesenchymal stromal cell-derived extracellular vesicles (MSC EVs) to carry the microRNA let-7b-5p as a dual anti-infective and anti-inflammatory treatment. MSC EVs are low-immunogenicity platforms with innate antimicrobial and immunomodulatory properties, whereas let-7b-5p reduces inflammation. This study demonstrates that MSC EVs effectively blocked the formation of antibiotic-resistant P. aeruginosa biofilms on primary human bronchial epithelial cells (pHBECs), and let-7b-5p loading into MSC EVs conferred additional anti-inflammatory effects by reducing P. aeruginosa-induced IL-8 secretion by pHBECs. This approach holds promise for improving outcomes for people with CF, and future work will focus on optimizing delivery strategies and expanding the clinical applicability of MSC EVs to target other CF-associated pathogens.NEW & NOTEWORTHY This is the first study demonstrating that mesenchymal stromal cell extracellular vesicles (MSC EVs) block antibiotic-resistant P. aeruginosa biofilm formation and that let-7b-5p-loaded MSC EVs reduce inflammation in CF primary human bronchial epithelial cells.

Bronchopulmonary dysplasia (BPD) is the most common adverse outcome in preterm neonates and a high risk for early-onset emphysema and asthma. BPD is characterized by disrupted alveolar and microvascular development due to a variety of pathogenic factors, such as hyperoxia, inflammation, and dysbiosis. The resulting clinical manifestations are challenging, and current treatment options are limited. To improve therapeutic options, it is imperative to understand underlying causes. Resident lung mesenchymal stromal cells (L-MSCs) are important for alveolar microvascularization, repair, and regeneration. Here, we report the immediate effects of hyperoxia- and antibiotics-induced reduced bacterial load on L-MSCs and alveolar development using the hyperoxia-induced BPD mouse model. Newborn mice were exposed to hyperoxia from postnatal day 4 (P4) to P14, with room air recovery from P14 to P21. Dams received antibiotics-supplemented water (ampicillin, gentamycin, and vancomycin) from embryonic day 15 (E15) to P21. Hyperoxia significantly impaired alveolar development between P14 and P21, whereas both hyperoxia and antibiotic exposure impaired lung microvascular development. Moreover, hyperoxia reduced the number of pericytes, proliferative mesenchymal progenitors, Col13a1^POS matrix fibroblasts, and P2RY14^POS alveolar myofibroblasts. RNA sequencing (RNA-seq) of LY6A-sorted L-MSCs revealed differential expression of 103 genes in hyperoxia, 10 of which are related to mast cell biology. Antibiotic exposure also altered mesenchymal cell distribution, suggesting an additional impact on lung development. The transcriptomic landscape and distribution of important L-MSC subtypes and microvascular development are affected by hyperoxia and antibiotic exposure in a BPD mouse model. In conclusion, we show that hyperoxia- and antibiotics-induced reduced bacterial load affect the mesenchymal cell population, which may contribute to the development of BPD.NEW & NOTEWORTHY Bronchopulmonary dysplasia (BPD) is associated with preterm-born children, and antibiotic treatment increases the incidence. Lung repair is affected in BPD, and here we focused on the LY6A^POS lung mesenchymal cells (L-MSCs), which modulate repair. We show that hyperoxia, which induces BPD in rodents, and antibiotics affect the transcriptome of these cells, resulting in altered signaling to mast cells. Antibiotics also affected the hyperoxia-induced changes in the cellular composition of L-MSCs at early alveologenesis.

Excessive mucus in the airways is an underlying pathological feature of many airway diseases, including asthma. Therapeutic options to reduce mucus production in the airways remain limited. One possible therapeutic target is the airway sympathetic nerves. Although lung sympathetic innervation has been considered sparse, sympathetic nerves secrete neurotransmitters that act on adrenergic receptors, including β₂-adrenergic receptor (β₂AR). Interestingly, in experimental models, chronic use of β₂AR agonists can augment mucus secretion. Thus, in the present study, we tested the hypothesis that airway sympathetic nerves regulate mucus production in the airway in response to the type 2 cytokine interleukin 13 (IL-13). We performed airway sympathectomy using intranasal instillation of the synthetic neurotoxin 6-hydroxydopamine (6-OHDA). Airway sympathectomy attenuated multiple IL-13-mediated airway deficits, including density of goblet cells containing neutral mucins, transcriptional ratio of mucin 5ac (Muc5ac) to mucin 5b (Muc5b), and airway elastance and tissue damping. Although total Muc5ac and Muc5b transcript levels and Muc5ac and Muc5b protein levels in bronchoalveolar lavage were not significantly altered, these changes suggest that airway sympathectomy modifies goblet cell phenotype and mucin composition. Airway sympathectomy also dampened IL-13-mediated increases in total lung transcripts important for regulating allergic responses, including interleukin 6, complement component 3, and colony-stimulating factor. This study reveals that airway sympathetic nerves regulate physiologic, molecular, and inflammatory responses to type 2 (IL-13-mediated) airway inflammation and raises the possibility that they may serve as potential targets for therapeutic intervention.NEW & NOTEWORTHY The role of airway sympathetic nerves in regulating airway responses remains largely undefined. We demonstrated that chemical depletion of airway sympathetic nerves attenuates specific IL-13-induced airway deficits at the molecular, cellular, and functional level. Our data suggest that airway sympathetic nerves may represent novel therapeutic targets to alleviate some pathologic features due to type 2 (IL-13-mediated) airway inflammation.

Biomarkers based on volatile organic compounds (VOCs) measured in human breath have been investigated in a wide range of diseases. However, the excitement surrounding such biomarkers has not yet translated to the discovery of any that are ready for clinical implementation. A lack of standardization in sampling and analysis has been identified as a key obstacle to the validation of potential biomarkers in multicenter studies. Some progress toward standardization has been made, but further progress is required to optimize sampling protocols and account for the confounding factors identified. This review highlights the important role that in silico (i.e., computational modeling) methods can play in addressing these gaps. Moreover, we discuss their potential for targeting and validating disease biomarkers by mechanistically linking them to the underlying metabolomic processes. We explore pertinent examples of mathematical, computational, and machine learning models that have proven useful in similar contexts, such as the development of fractional exhaled nitric oxide sampling standards. We then propose a roadmap outlining how existing and new modeling approaches can be applied to the problem of standardization in breathomics research.

Session V of the inaugural biennial Research Symposium on Pulmonary Injury and Repair of the Endothelium showcased cutting-edge research on pulmonary endothelial crosstalk with end organs and its role in vascular disease. Growing evidence suggests that communication between injured organs and distal vascular beds plays a critical role in the pathogenesis of complex conditions such as sepsis, acute respiratory distress syndrome, pulmonary arterial hypertension, and heart failure with preserved ejection fraction. Circulating mediators-including heparan sulfate fragments, proinflammatory cytokines, mitochondrial damage-associated molecular patterns, bone morphogenetic protein 9, bile acids, and nitric oxide-have emerged as key factors linking pulmonary endothelial dysfunction to neural impairment, acute kidney injury, subclinical liver injury, and left-sided heart disease. This review highlights recent advances in the field, identifies critical knowledge gaps, and outlines future research directions aimed at elucidating mechanisms of multiorgan dysfunction and identifying novel therapeutic targets.