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

{"title":"Leveraging intrinsic non-sinusoidal patterns to infer search behavior to predict exposure to respiratory stressors.","authors":"Anju Bimal, Szilard L Beres, Victoria Ribeiro Rodrigues, Barbara K Smith, Paul W Davenport, Nicholas J Napoli","doi":"10.1152/ajplung.00379.2024","DOIUrl":"10.1152/ajplung.00379.2024","url":null,"abstract":"<p><p>This study introduces a novel entropy-based methodology to quantitatively characterize nonlinear transient breathing dynamics under respiratory stress. Environmental and pathophysiological stressors can disrupt the respiratory system's gas exchange, leading to compromise and compensatory mechanisms. We present a data-driven approach that systematically evaluates classical respiratory features alongside novel entropic features as key indicators under respiratory stress. We demonstrate that conventional metrics like breathing rate (<i>B</i>_R), time of inspiration (<i>T</i>_I), and expiration (<i>T</i>_E) fail to capture discriminating features needed to detect early ventilatory instability and predict intervention needs. An exhaustive analysis of key respiratory fiducial points using entropic methods led to novel features for understanding respiratory mechanics and classifying respiratory states. We found that the nonlinear dynamics of the transition times between inspiratory and expiratory phases (interphases) are crucial for assessing adaptability to respiratory challenges. This metric quantifies the complexity of transition duration (acceleration and deceleration between phases) and is essential for predicting declining breathing states. Our predictive model incorporating these novel approaches showed superior discriminating ability over models using classical features, achieving a 50.76% increase in predictive power as measured by the area under the curve (AUC). These findings underscore the effectiveness of this entropy-based approach for early detection of respiratory compromise, with the best model achieving an AUC of 0.784. The results have significant implications for improving clinical monitoring of acute respiratory failure and managing chronic respiratory conditions.<b>NEW & NOTEWORTHY</b> Entropy-based metrics analyzing respiratory phase transitions (inspiration-to-expiration and expiration-to-inspiration) detect respiratory compromise under hypoxic conditions better than standard breathing rate measurements. Analysis of nonlinear dynamics during these transitions reveals key ventilatory adaptations during exposure to respiratory stressors. Measuring timing variations at phase transitions improves predictive model performance in detecting exposure to hypoxic environments by a 50.76% increase in area under the curve (AUC) vs. classical methods.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L134-L160"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PMN recruitment in inflammatory lung injury models follows classical transendothelial migration paradigms requiring PECAM-1 and CD99.","authors":"Maureen E Haynes, Erika Arias, David P Sullivan, William A Muller","doi":"10.1152/ajplung.00069.2025","DOIUrl":"10.1152/ajplung.00069.2025","url":null,"abstract":"<p><p>Immune cells are recruited to sites of inflammation in a stepwise process involving a symphony of signals and receptors. In the systemic circulation, the step at which immune cells migrate out of the blood and across the endothelium, transendothelial migration, occurs via homophilic interactions between leukocyte PECAM-1 and CD99 and endothelial cell PECAM-1 and CD99. Previous work showed that rolling and adhesion of immune cells in the lung vasculature does not follow the classical paradigm of inflammatory recruitment; however, the transmigration step of this process has largely gone understudied. In this study, we demonstrate that polymorphonuclear cells (PMNs) use PECAM-1 and CD99 when transmigrating in response to murine chemical, bacterial, and ischemia/reperfusion lung injury (IRI). We demonstrate that recruitment of PMNs in response to both Gram-positive and Gram-negative bacteria is PECAM-1- and CD99-dependent. We implemented a method of intravital microscopy (IVM) of the pulmonary vasculature after IRI, with which we directly visualized and quantified transmigration. We demonstrate, in real time, that PMN enter the alveoli by crossing alveolar capillaries. Because PMNs are known to be independent mediators of both tissue damage and resolution of inflammation, we tested these effective blocking antibodies for survival effects in models of 50-60% mortality, but found none. In summary, our study shows that the classical transmigration protein interactions are necessary for the transmigration of PMNs into the airspace during response to four distinct inflammatory stimuli.<b>NEW & NOTEWORTHY</b> Previous studies have shown that neutrophil extravasation in the lung was selectin-independent and the requirement for leukocyte integrins was stimulus-dependent. This study demonstrates that PECAM-1 and CD99 are required for PMN transmigration during chemical, bacterial, and ischemia/reperfusion lung inflammation. We show directly in real time, using intravital microscopy, that neutrophils extravasate from alveolar capillaries. Blocking antibodies against PECAM-1 or CD99 prevented transmigration into the lung airspace, just as they prevent transmigration in the systemic circulation.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L112-L125"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144186294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maternal diabetes and lung health: an unexplored risk factor for COPD?","authors":"Sriyani Ranatunga, Christopher D Pascoe","doi":"10.1152/ajplung.00046.2025","DOIUrl":"10.1152/ajplung.00046.2025","url":null,"abstract":"<p><p>Chronic obstructive pulmonary disease (COPD), the fourth leading cause of death worldwide, is traditionally considered a disease of smoking. However, <20% of people who smoke develop COPD, indicating the disease is complex, resulting from the interplay of genetic and environmental factors. Emerging evidence highlights the importance of exposure in early life to environmental irritants that impair fetal lung development and subsequent lung function trajectories, increasing risk for future COPD. Specifically, childhood asthma, preterm birth, and surfactant deficiency have been associated with lung function impairments and an increased COPD risk later in life. Furthermore, prenatal exposure to cigarettes influences sensitivity of individuals to smoking in their later life. A mounting body of evidence now indicates that diabetes exposure during pregnancy increases the risk for several childhood conditions linked to COPD risk, suggesting that maternal diabetes may be an unexplored risk factor for COPD. This article reviews the current literature on the influence of maternal diabetes on known early-life COPD risk factors (asthma and preterm birth), and identifies knowledge gaps that need to be addressed to pindown a potential association with COPD. Specifically, whether exposure to maternal diabetes influences offspring risk for COPD through already identified risk modifiers, or directly by altering lung function trajectories or sensitivity to cigarettes. Maternal diabetes rates are rising worldwide, with type 2 diabetes mellitus (T2DM) during pregnancy and gestational diabetes mellitus (GDM) nearly doubling over the last 15 years. Understanding how prenatal diabetes influences COPD risk is imperative to establishing whether intervening early can prevent COPD in this population.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L126-L133"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144214664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The nitrofen/bisdiamine murine model of congenital diaphragmatic hernia has a pulmonary hypertension vascular phenotype consistent with human CDH.","authors":"Cailin R Gonyea, Yuanjun Shen, Katherine M Nelson, Rylie N Bird, Rachel M Gilbert, Oluyinka O Olutoye, Sundeep G Keswani, Jason P Gleghorn","doi":"10.1152/ajplung.00233.2024","DOIUrl":"10.1152/ajplung.00233.2024","url":null,"abstract":"<p><p>Congenital diaphragmatic hernia (CDH)-associated pulmonary hypertension (CDH-PH) has severe implications for the survival of patients with CDH; however, CDH-PH is often refractory to pulmonary vasodilators, rendering it difficult to treat. As such, models are necessary to study the etiology, mechanism, onset, and progression of pulmonary vascular remodeling in CDH. Despite several established murine models of CDH, no characterized CDH-PH or CDH-associated pulmonary vascular remodeling murine model exists. In this work, we assessed the nitrofen/bisdiamine (N/B) murine CDH model for pulmonary hypertension (PH) hallmarks to establish its usefulness as a model for studying mechanisms leading to CDH-PH. To do so, we evaluated key metrics of vascular PH at two different gestational time points and compared the results to sex- and age-matched human CDH tissue sections and results from a meta-analysis of published data of human CDH samples. We found that vessel rarefaction, smooth muscle hypertrophy, and adventitial extracellular matrix deposition were present in the N/B CDH murine model at <i>E18.5</i> in late gestation. In addition, this same vascular PH phenotype was present much earlier in development at <i>E16.5</i>, after normal diaphragmatic development and closure, but still within the pseudoglandular phase of lung development. Finally, comparisons with human CDH data confirm that the N/B CDH murine model recapitulates the pulmonary hypertension vascular phenotype seen in human CDH lung sections. Together, these data validate a mouse CDH-PH model with the ability to genetically perturb pathways that may exacerbate or improve CDH-PH outcomes, which could, in turn, lead to therapies or diagnostic markers of CDH-PH severity in utero.<b>NEW & NOTEWORTHY</b> Pulmonary hypertension (PH) is a severe complication of congenital diaphragmatic hernia (CDH), yet mechanisms and potential interventions remain poorly understood, partly due to the lack of animal models. This study validated that the nitrofen/bisdiamine (N/B) CDH mouse model recapitulates a PH vascular phenotype, including vessel rarefaction, smooth muscle hypertrophy, and remodeling that is benchmarked to human CDH tissues. These findings suggest that this model is a robust in vivo tool for the mechanistic study of CDH-PH.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L48-L60"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144186295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent ventilatory responses during opioid-induced respiratory depression in response to repeated fentanyl use.","authors":"Karan G Rai, Chinwendu U Nwakudu, Caroline C Szujewski, Brigitte M Browe, Gia E Fisher, Willard W Sharp, Andrew K Tryba, Alfredo J Garcia","doi":"10.1152/ajplung.00302.2024","DOIUrl":"10.1152/ajplung.00302.2024","url":null,"abstract":"<p><p>Opioid-induced respiratory depression (OIRD) is the hallmark of opioid overdose and a major risk factor for death due to fentanyl use. Although repeat opioid use (ROU) elevates the risk of death, understanding its influence over breathing and its control has been poorly resolved. We developed a mouse model of recurrent fentanyl use over 5 days to examine how ROU impacts breathing and activity from the pre-Bötzinger complex (preBötC), the brainstem network driving inspiratory rhythmogenesis. Initial fentanyl use caused a profound metabolic crisis during OIRD involving a mismatch between ventilation and oxygen consumption. By <i>day 5</i> of ROU, 77% of mice exhibited an adaptive ventilatory response following ROU, which was accompanied by an improved relationship between ventilation and oxygen consumption during OIRD. However, in the remaining minority, the adaptive response during OIRD failed to emerge following ROU. This divergence emphasizes the heterogeneity in ventilatory and metabolic outcomes following ROU. Moreover, following ROU, rhythmogenesis in the preBötzinger complex was less sensitive to mu-opioid receptor agonism, indicating that adaptation to ROU involves centrally mediated changes in this brainstem network. These findings reveal a series of physiological changes following ROU, typically resulting in improved ventilation and oxygenation during OIRD. Such changes, or lack of thereof, may contribute to the unpredictable nature of overdose susceptibility among opioid users.<b>NEW & NOTEWORTHY</b> Recurring fentanyl use is a significant factor contributing to opioid-related deaths, yet the physiological impact of repeat opioid use on breathing remains poorly understood. This study demonstrates that divergent ventilatory responses to opioids emerge following repeated fentanyl administration. These responses coincide with changes in oxygen consumption and inspiratory rhythmogenesis from the preBötzinger complex. These observations advance an understanding of the physiological basis for susceptibility and tolerance among individuals likely to succumb to opioid overdose.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L161-L171"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Olfactomedin-4 elevation in pediatric acute respiratory distress syndrome.","authors":"Ryan O'Sullivan, Matthew N Alder, Celeste G Dixon, Donglan Zhang, Nishi Srivastava, Nadir Yehya","doi":"10.1152/ajplung.00040.2025","DOIUrl":"10.1152/ajplung.00040.2025","url":null,"abstract":"<p><p>Neutrophils play a key role in acute respiratory distress syndrome (ARDS). The neutrophil marker olfactomedin-4 (OLFM4) has been implicated with worse outcomes in pediatric sepsis; however, OLFM4 has not been studied in pediatric ARDS. Therefore, we performed a secondary analysis of a prospective cohort of children with Berlin-defined ARDS with plasma collected on <i>day 0</i> of ARDS, testing for an association between OLFM4 and 28-day mortality, 7-day dialysis-free survival, and 28-day ventilator-free days (VFDs), adjusting for age, ARDS etiology, immunocompromised status, and arterial partial pressure of oxygen ([Formula: see text])/fraction of inspired oxygen ([Formula: see text]). We also tested the ability of LPS and histones to affect OLFM4 expression in vitro. In 333 children with ARDS (21% nonsurvivors), OLFM4 was higher in nonsurvivors, in severe ARDS, in hyperinflammatory ARDS, and in those with multiple organ failures. In multivariable regression, OLFM4 was associated with higher mortality, higher probability of dialysis by <i>day 7</i>, and fewer VFDs. In stratified analyses, the association between OLFM4 and worse outcomes did not differ between infectious and noninfectious ARDS. In vitro, OLFM4 expression increased following H3 exposure in undifferentiated neutrophils, which was partly mitigated by toll-like receptor (TLR) antagonism. Overall, OLFM4 was associated with worse outcomes in pediatric ARDS. Histone H3 could induce OLFM4 expression in neutrophils, thus linking damage-associated molecular patterns to neutrophil polarization, which may represent a possible targetable pathway in pediatric ARDS.<b>NEW & NOTEWORTHY</b> Olfactomedin-4 (OLFM4) was associated with higher mortality, higher probability of dialysis by <i>day 7</i>, and fewer ventilator-free days (VFDs) in a pediatric acute respiratory distress syndrome (ARDS) cohort. In vitro, OLFM4 increased following H3 exposure in undifferentiated neutrophils, which was partly mitigated by toll-like receptor (TLR) antagonism. OLFM4 appears to be a marker, and potentially a mediator, of pathological inflammation and end-organ damage in ARDS.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L172-L182"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stereological analysis of the naked mole-rat <i>Heterocephalus glaber</i> lung provides evidence of altered surfactant function and late alveolarization.","authors":"Florian Geltinger, Susanne Holtze, Thomas Bernd Hildebrandt, Matthias Ochs, Christina Brandenberger","doi":"10.1152/ajplung.00246.2024","DOIUrl":"10.1152/ajplung.00246.2024","url":null,"abstract":"<p><p>Naked-mole rats (NMRs; <i>Heterocephalus glaber</i>) exhibit unique biological traits such as resistance to cancer, exceptional longevity, and high tolerance to low-oxygen environments. However, little is known about the lung structure of this eusocial species. Here, the lungs of adult NMRs were qualitatively examined using light and electron microscopy, followed by structural quantification of the alveolar region by means of stereology. One queen (>18 years) was also included in the study. The data normalized to body weight (BW) were furthermore compared to that of young and old mice (<i>Mus musculus</i>) as well as the expression of genes of surfactant proteins. Qualitatively, NMRs showed larger conducting airways compared to mice. Additionally, alveolar septa with a double-layered capillary network were observed in NMRs, indicating microvascular maturation and late alveolarization. Stereological analysis of the lung parenchyma revealed a lower septal surface area and alveolar epithelial type II (AEII) cell number per BW in NMRs compared to mice. However, in NMRs, the AEII cells were larger with a higher content of lamellar bodies, resulting in more intracellular surfactant per BW. Furthermore, the expression of surfactant protein B (<i>Sftpb</i>) was prominently higher in NMRs. The queen showed a larger mean alveolar volume, but no other age-related structural alterations were observed. The results indicate that NMRs are capable of late alveolarization, which is in line with their good regenerative potential. Additionally, NMRs have more intracellular surfactant and higher expression of <i>Sftpb</i>, suggesting functional alterations in their surfactant system possibly as an environmental adaptation.<b>NEW & NOTEWORTHY</b> Naked mole-rats (NMRs) can adapt to hypoxic environments and are the longest-living rodents. Comparison of their lung structure with that of mice revealed that NMRs have a reduced alveolar surface area per body weight but an increased pool of intracellular surfactant. Additionally, the septa of NMRs were thicker with an occasional double-layered capillary network. These features indicate a high regenerative potential with late alveolarization and environmental adaptation, even in old animals (>18 years).</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L84-L96"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The bronchoalveolar proteome changes in obesity.","authors":"William G Tharp, Carlos A Gartner, Yulica Santos-Ortega, Calvin P Vary, S Patrick Bender, Anne E Dixon","doi":"10.1152/ajplung.00054.2025","DOIUrl":"10.1152/ajplung.00054.2025","url":null,"abstract":"<p><p>Obesity contributes to pulmonary dysfunction through poorly understood biochemical mechanisms. Chronic inflammation and altered cellular metabolism have emerged as pathological changes across organ systems in obesity, but whether similar changes occur in lungs with obesity is unknown. We collected bronchoalveolar lavage fluid (BALF) from right upper lobe and lingula pulmonary subsegments of 14 adults (7 males/7 females) with body mass indexes (BMIs) ranging from 24.3 to 50.9 kg/m² without lung disease. Proteomes were measured using sequential window acquisition of all theoretical fragment ion spectra (SWATH) mass spectrometry. Proteomic composition and pathway enrichments were examined for the cohort and as a function of BMI. BALF proteomic compositions were consistent with earlier studies and had improved protein identification. We found minimal differences in BALF proteomes between lavage regions. Five proteins were strongly correlated with BMI (False Detection Rate/FDR-adjusted <i>P</i> values < 0.05) and 11 had weaker correlation (FDR-adjusted <i>P</i> values 0.05-0.1). These proteins included acute phase reactants and complement factors. Few proteomic differences between biological sexes were detected, but some of them coincided with BMI-related proteins. Pathway enrichments impacted by BMI included innate immunity, antifibrinolysis, oxidative stress, and lipid metabolism. The bronchoalveolar microenvironment is altered by obesity in humans without lung disease. Pathway alterations associated with BMI included coagulation and fibrinolysis, redox and oxidative stress, energy metabolism, and humoral immune function. Our data support the theory that conserved biochemical and cellular changes in obesity may be fundamental mechanisms of dysfunction in multiple tissues but the specific impact on pulmonary function or disease is not yet known.<b>NEW & NOTEWORTHY</b> Obesity is thought to cause deleterious changes in lung biochemistry, but data in humans are lacking. We measured the alveolar proteome in bronchoalveolar lavages from subjects with a wide range of body mass index and no lung disease. We found changes in proteins and pathways associated with increasing body mass index that are similar to pathological changes observed in other tissues and may constitute mechanisms of pulmonary dysfunction in obesity.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L35-L47"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal calcium signaling patterns underlying opposing effects of histamine and TAS2R agonists in airway smooth muscle.","authors":"Stanley Conaway, Joshua Richard, Deepak A Deshpande","doi":"10.1152/ajplung.00058.2025","DOIUrl":"10.1152/ajplung.00058.2025","url":null,"abstract":"<p><p>Intracellular calcium (Ca²⁺) release via phospholipase C (PLC) following G-protein-coupled receptor (GPCR) activation is typically linked to membrane depolarization and airway smooth muscle (ASM) contraction. However, recent findings show that bitter taste receptor agonists, such as chloroquine (CQ), induce a paradoxical and potent relaxation response despite activating the Ca²⁺ signaling pathway. This relaxation has been hypothesized to be driven by a distinct compartmentalization of calcium ions toward the cellular periphery, subsequently leading to membrane hyperpolarization, in contrast to the contractile effects of histamine. In this study, we further investigate the spatiotemporal dynamics of Ca²⁺ signaling in ASM cells using single-cell microscopy and deep learning-based segmentation, integrating the results into a comprehensive model of ASM ion channel dynamics to compare the effects of histamine, CQ, and flufenamic acid (FFA). Our results show that histamine induces a strong, synchronized calcium release, nearly twice as high as that of CQ, which produces a sustained but lower-magnitude response. Per-cell analysis reveals more variable and asynchronous Ca²⁺ signaling for CQ and FFA, with higher entropy compared with histamine. Integrating these findings into an ASM ion channel model, we observed that histamine-mediated Ca²⁺ release activates voltage-gated Ca²⁺ and Na⁺ channels (leading to depolarization). In contrast, CQ preferentially engages BKCa, SKCa, and chloride channels (promoting hyperpolarization). These findings provide insights into the unique mechanisms by which bitter taste receptor agonists can modulate ASM tone, offering potential therapeutic strategies for relaxing ASM and alleviating airway hyperresponsiveness in conditions such as asthma.<b>NEW & NOTEWORTHY</b> Using machine-learning methods, these studies identify spatiotemporal differences in calcium responses between agonists of Gq-coupled receptors and bitter taste receptors in airway smooth muscle cells. The findings provide deeper insights into the mechanism of action of bitter tastant-induced airway smooth muscle relaxation.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L70-L83"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12188627/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperoxia-induced senescence in fetal airway smooth muscle cells: role of mitochondrial reactive oxygen species and endoplasmic reticulum stress.","authors":"Maunick L Koloko Ngassie, Michael A Thompson, Benjamin B Roos, Savita Ayyalasomayajula, Antony B Lagnado, João F Passos, Christina M Pabelick, Y S Prakash","doi":"10.1152/ajplung.00348.2024","DOIUrl":"10.1152/ajplung.00348.2024","url":null,"abstract":"<p><p>Premature infants are at higher risk for developing chronic lung diseases, especially following supplemental oxygen (hyperoxia) in early life. We previously demonstrated that moderate hyperoxia (<60% O₂) induces cellular senescence in fetal airway smooth muscle cells (fASM) and fibroblasts. However, the mechanisms underlying O₂-induced senescence are still under investigation. In this study we investigated the role of endoplasmic reticulum (ER) stress and mitochondrial dysfunction, using fASM cells exposed to 21% O₂ (normoxia) vs. ∼50% O₂ (hyperoxia). Normoxia or hyperoxia-exposed fASM were treated with the ER stress inhibitor salubrinal [12.5 μM], the antioxidant MitoQ [100 nM], or the mitochondrial fission inhibitor Mdivi-1 [10 μM]. Samples were harvested at <i>day 2</i>, <i>3</i>, and <i>7</i> and analyzed for markers of senescence, oxidative stress, ER stress response, and mitochondrial dynamics using protein analysis and fluorescence microscopy. Hyperoxia enhanced senescence, upregulating multiple markers of DNA damage in particular, cyclin-dependent cell cycle regulator p21, cytosolic and mitochondrial reactive oxygen species (ROS) levels, mitochondria fragmentation, and anti-apoptosis B-cell lymphoma-extra large (Bcl-xL), while downregulating the proliferation marker Ki-67. Hyperoxia also activated all three ER stress pathways. However, the level of p21 and/or Bcl-xL was decreased in hyperoxia-exposed cells treated with the ER stress inhibitor salubrinal or the antioxidant MitoQ, but not the fission inhibitor Mdivi-1. These findings highlight the role of mitochondrial ROS and ER stress in hyperoxia-induced senescence of fASM and suggest that mitochondrial-targeted antioxidants and/or inhibitors of ER stress pathways can blunt the detrimental effects of hyperoxia in developing lungs.<b>NEW & NOTEWORTHY</b> Supplemental O₂ (hyperoxia) in premature infants detrimentally affects bronchial airways leading to increased senescence. Understanding the mechanisms by which hyperoxia initiates senescence in developing airways is critical for future therapeutic strategies. The current study showed that hyperoxia-induced senescence is mediated through increased mitochondrial reactive oxygen species and endoplasmic reticulum (ER) stress. ER stress inhibitors or mitochondria-targeted antioxidants may represent future therapies to blunt detrimental effects of supplemental oxygen in developing lungs.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L1-L18"},"PeriodicalIF":3.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12173779/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}