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

{"title":"Lower levels of senescence in human lung mesenchymal stromal cells compared with lung fibroblasts: implications for tissue regeneration in COPD.","authors":"Marissa Wisman, Dennis M L W Kruk, Wierd Kooistra, Irene H Heijink, Roy R Woldhuis","doi":"10.1152/ajplung.00366.2024","DOIUrl":"10.1152/ajplung.00366.2024","url":null,"abstract":"<p><p>In patients with chronic obstructive pulmonary disease (COPD), lung-tissue regenerative mechanisms are thought to be exhausted, to which cellular senescence may contribute. Lung-derived mesenchymal stem/stromal cells (LMSCs) constitute a potent supportive cell type able to self-renew and promote alveolar regeneration. We hypothesized that LMSCs are less sensitive to senescence induction in COPD than other supportive cells, for example, lung fibroblasts (LFs), and therefore more promising in regenerative strategies. We compared senescence markers in LMSCs and LFs from the same subjects with/without replicative- and stress-induced senescence. LMSCs and LFs were isolated from COPD and non-COPD lung tissue using cell-specific protocols and expanded for multiple passages under the same culture conditions. Proliferation, senescence-associated β-galactosidase (SA-β-gal) activity, expression of senescence markers (<i>CDKN2A/P16</i>, <i>CDKN1A/P21</i>, and <i>LMNB1</i>), P21 protein levels, secretion of senescence markers (IL-6 and IL-8), and alveolar growth factors [hepatocyte growth factor (HGF) and fibroblast growth factor 10 (FGF10)] were assessed in the absence/presence of paraquat (PQ). We observed higher population doublings, and lower SA-β-gal positive cells and P21 protein levels in LMSCs compared with LFs at baseline. COPD-derived LFs had lower population doublings and higher cellular size than controls, which was not observed for COPD-derived LMSCs. LMSCs displayed lower sensitivity to PQ-induced senescence compared with LFs (COPD and control combined). Senescence induction was accompanied by increased IL-6 and IL-8 secretion, to which fibroblasts were more sensitive, and by reduced FGF10 but not HGF expression in both cell types. This study demonstrates that LMSCs have lower levels of senescence and lower sensitivity toward senescence induction compared with LFs, affecting cell expansion and FGF10 expression. This suggests that LMSCs are better suited for cell-based therapies.<b>NEW & NOTEWORTHY</b> We demonstrate that LMSCs are less sensitive to senescence induction by oxidative stress and replication than LFs, which was accompanied by an increased ability to expand. This makes LMSCs more suitable for cell-based therapies in COPD. As senescence affected growth factors involved in alveolar repair, specifically FGF10 expression in both LMSCs and LFs, we additionally suggest that the development of anti-senescence strategies may promote endogenous tissue repair in COPD.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L858-L865"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143972916","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":"Endogenous opioids and the development of the mammalian respiratory control network.","authors":"Jessica R Whitaker-Fornek, Erica S Levitt","doi":"10.1152/ajplung.00316.2024","DOIUrl":"10.1152/ajplung.00316.2024","url":null,"abstract":"<p><p>It is well known that exogenous opioids such as morphine and fentanyl can depress breathing by inhibiting brainstem breathing control circuit activity. However, the role of endogenous opioids in breathing control is less clear. Endogenous opioid peptides and opioid receptors are expressed within the embryonic brainstem at the same time as when respiratory rhythm-generating neurons begin to mature. However, the extent to which endogenous opioids participate in respiratory control maturation is not known. Therefore, our goal is to review the current state of knowledge for the role of endogenous opioids in breathing control development. We set the stage by reviewing how endogenous opioid peptides regulate breathing in young and adult mammals. We describe the prenatal and postnatal development of endogenous opioid peptides and receptors in relation to breathing development. In addition, we review the effects of exogenous opioids on breathing during early life and identify areas in need of further study. We also broadly describe pain circuitry development to compare the opioid influence on nociception with how opioids impact breathing. We map the locations of endogenous opioid peptide production in the adult and developing brainstem respiratory network. Last, we propose clinical breathing conditions that may involve the endogenous opioid system. Given advances in tools for detecting endogenous opioid peptide release and the evidence reviewed herein, future research will yield new discoveries in the role of endogenous opioids in breathing across the lifespan.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L901-L918"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143958475","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 extracellular matrix protein periostin is required for wound repair in primary human airway epithelia.","authors":"Lorena A Tran, Michael Catlin, Scott Schecter, Andrew L Thurman, Shreya Ghimire, Rosarie A Tudas, Brandon Bettis, Ryan M Gannon, Joseph Zabner, Alejandro A Pezzulo","doi":"10.1152/ajplung.00039.2025","DOIUrl":"10.1152/ajplung.00039.2025","url":null,"abstract":"<p><p>Type 2 inflammation and epithelial-to-mesenchymal transitions (EMTs) play critical roles in airway repair after damage from allergens or parasites. The matricellular protein periostin (POSTN) has increased expression in inflammatory conditions and has been implicated in fibrosis and EMT, suggesting a role in airway repair. This study investigates the role of periostin in airway epithelial and lung fibroblast wound repair using an in vitro wound model. Our results demonstrate that the type 2 cytokine IL-13 induces periostin secretion from primary human airway epithelial basal cells. Periostin knockdown in human airway epithelial cells (HAEs) and human lung fibroblasts (HLFs) impairs wound closure, indicating that periostin is required for airway repair. In a coculture model of HAE and HLFs, fibroblast-secreted POSTN is required for airway epithelial wound repair, suggesting that periostin is involved in paracrine signaling between the two cell types. These findings highlight periostin's critical function in epithelial and fibroblast-mediated wound repair, suggesting its potential as a therapeutic target for diseases characterized by aberrant wound healing and fibrosis, such as asthma and idiopathic pulmonary fibrosis.<b>NEW & NOTEWORTHY</b> This article highlights the critical role of periostin (POSTN) in airway epithelial and fibroblast-mediated wound repair. Moreover, the study reveals a paracrine signaling loop between airway epithelial basal cells and lung fibroblasts, emphasizing periostin's therapeutic potential for diseases like asthma and idiopathic pulmonary fibrosis.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":"328 6","pages":"L826-L831"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12100768/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960946","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":"Store-operated Ca²⁺ entry is involved in endothelium-to-mesenchymal transition in lung vascular endothelial cells.","authors":"Aleksandra Babicheva, Ibrahim Elmadbouh, Shanshan Song, Michael A Thompson, Ryan Powers, Pritesh P Jain, Amin Izadi, Jiyuan Chen, Lauren Yung, Sophia Parmisano, Cole Paquin, Wei-Ting Wang, Yuqin Chen, Ting Wang, Mona Alotaibi, John Y-J Shyy, Patricia A Thistlethwaite, Jian Wang, Ayako Makino, Y S Prakash, Christina M Pabelick, Jason X-J Yuan","doi":"10.1152/ajplung.00400.2024","DOIUrl":"10.1152/ajplung.00400.2024","url":null,"abstract":"<p><p>Endothelial-to-mesenchymal transition (EndMT) is a biological process that converts endothelial cells to mesenchymal cells with increased proliferative and migrative abilities. EndMT has been implicated in the development of pulmonary vascular remodeling in pulmonary arterial hypertension (PAH), a fatal and progressive lung vascular disease. Transforming growth factor β₁ (TGF-β₁), an inflammatory cytokine, is known to induce EndMT in many types of endothelial cells including lung vascular endothelial cells (LVECs). An increase in cytosolic free Ca²⁺ concentration ([Ca²⁺]_cyt) is a major stimulus for cellular proliferation and phenotypic transition, but it is unknown whether Ca²⁺ signaling is involved in EndMT. In this study, we tested the hypothesis that TGF-β₁-induced EndMT in human LVEC is Ca²⁺-dependent. Treatment of LVEC with TGF-β₁ for 5-7 days resulted in increase in SNAI1/2 expression, induction of EndMT, upregulation of STIM/Orai1, and enhancement of store-operated Ca²⁺ entry (SOCE). Removal (or chelation) of extracellular or intracellular Ca²⁺ with EGTA or BAPTA-AM, respectively, abolished EndMT in response to TGF-β₁. Moreover, EGTA diminished TGF-β₁-induced increase in SNAI in a dose-dependent manner. Knockdown of either STIM1 or Orai1 was sufficient to prevent TGF-β-mediated increase in SNAI1/2 and EndMT but did not rescue the continuous adherent junctions. Blockade of Orai1 channels by AnCoA4 inhibited TGF-β-mediated EndMT and restored PECAM1-positive continuous adherent junctions. In conclusion, intracellular Ca²⁺ signaling plays a critical role in TGF-β-associated EndMT through enhanced SOCE and STIM1-Orai1 interaction. Thus, targeting Ca²⁺ signaling pathways regulating EndMT may be a novel therapeutic approach to treat PAH and other forms of precapillary pulmonary hypertension.<b>NEW & NOTEWORTHY</b> EndMT has been reported to contribute to the pathogenesis of PAH. In this study, we aimed to determine the role of Ca²⁺ signaling in the development of EndMT in human lung vascular endothelial cells. Our data suggest that TGF-β₁ requires store-operated Ca²⁺ entry through STIM1/Orai channels to induce SNAI-mediated EndMT. For the first time, we demonstrated that TGF-β₁-induced EndMT is a Ca²⁺-dependent event, whereas inhibition of STIM1/Orai interaction attenuated EndMT in response to TGF-β₁.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L844-L857"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12169631/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143962642","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":"Vascular EC-SOD limits the accumulation, proinflammatory profibrotic reprogramming, and hyaluronan binding of interstitial macrophages in hypoxia.","authors":"Caitlin V Lewis, Thi-Tina N Nguyen, Timothy E Porfilio, Samuel D Burciaga, Janelle N Posey, Mariah Jordan, Daniel Colon Hidalgo, Kurt R Stenmark, Claudia Mickael, Christina Sul, Rebecca E Oberley-Deegan, Cassidy Delaney, Eva S Nozik","doi":"10.1152/ajplung.00399.2024","DOIUrl":"10.1152/ajplung.00399.2024","url":null,"abstract":"<p><p>Dysregulated redox signaling contributes to pulmonary hypertension (PH) and vascular depletion of the redox enzyme extracellular superoxide dismutase (EC-SOD) from smooth muscle cells [EC-SOD SMC knockout (KO)] worsens chronic hypoxic PH. Given the important role of macrophages in PH, this study aimed to determine if interstitial macrophages (IMs) and their interactions with hyaluronan (HA), a component of extracellular matrix (ECM), are modulated by vascular EC-SOD. Floxed wild-type, EC-SOD SMC KO, and SOD mimetic- or vehicle-treated mice were exposed to hypobaric hypoxia [∼10% fraction of inspired oxygen ([Formula: see text])], for 4, 14, or 21 days. Using flow cytometry, we demonstrated that the transient increase in IMs at <i>day 4</i> was exacerbated in EC-SOD SMC KO mice and prevented with SOD mimetic pretreatment. Highlighting the importance of targeting vascular oxidative stress in the early response to hypoxia, pretreatment with a single dose of EC-SOD mimetic decreased right ventricular systolic pressure, right ventricular hypertrophy, and small vessel muscularization at <i>day 21</i>. To assess IM phenotypic reprogramming in hypoxia, RNA-seq was performed on flow-sorted IMs revealing baseline proinflammatory activation and enhanced activation of vascular and ECM remodeling pathways in response to hypoxia in EC-SOD SMC KO IMs compared with controls. To further investigate the ECM remodeling response, we quantified IMs expressing the lymphatic vessel endothelial hyaluronan receptor 1 (Lyve1), and IM-hyaluronan binding. Lyve1⁺ IMs and Lyve1⁺ HA⁺ IMs were increased in response to hypoxia in EC-SOD SMC KO mice and accumulated in the perivascular space of the lung. In conclusion, vascular EC-SOD limits IM accumulation and proinflammatory profibrotic IM signaling, including perivascular accumulation of Lyve1⁺ IMs and their binding to hyaluronan.<b>NEW & NOTEWORTHY</b> Expression of the redox enzyme EC-SOD limits PH severity. Using vascular-selective EC-SOD depletion and SOD mimetic treatment in chronic hypoxic PH, we demonstrated that EC-SOD limits the hypoxia-induced accumulation of IMs. IMs from mice with low vascular EC-SOD were proinflammatory at baseline and enhanced ECM remodeling pathway activation in response to hypoxia. We identified Lyve1⁺ IMs as a perivascular, ECM-interacting subset that accumulate in hypoxia and could contribute to vascular remodeling in PH.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L885-L900"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956241","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":"TNFα-mediated subcellular heterogeneity of succinate dehydrogenase activity in human airway smooth muscle cells.","authors":"Sanjana Mahadev Bhat, Claire Catherine Creighton, Gary C Sieck","doi":"10.1152/ajplung.00396.2024","DOIUrl":"10.1152/ajplung.00396.2024","url":null,"abstract":"<p><p>Tumor necrosis factor-α (TNFα) is a pro-inflammatory cytokine, which mediates acute inflammatory effects in response to allergens, pollutants, and respiratory infections. Previously, we reported that TNFα increased maximum O₂ consumption rate (OCR) and mitochondrial volume density (MVD) in human airway smooth muscle (hASM) cells. However, TNFα decreased maximum OCR when normalized to mitochondrial volume. In addition, TNFα altered mitochondrial distribution and motility within hASM cells. Although high-resolution respirometry is valuable for assessing mitochondrial function, it overlooks mitochondrial structural and functional heterogeneity within cells. Therefore, a direct measurement of cellular mitochondrial function provides valuable information. Previously, we developed a confocal-based quantitative histochemical technique to determine the maximum velocity of the succinate dehydrogenase (SDH) reaction (SDH_max) in single cells and observed that cellular SDH_max corresponds with MVD. Therefore, we hypothesized that TNFα decreases SDH_max per mitochondrion in hASM cells. The hASM cells were treated with TNFα (20 ng/mL, 6 h, and 24 h) or untreated (time-matched control). Using three-dimensional (3-D) confocal imaging of labeled mitochondria and a concentric shell method for analysis, we quantified MVD, mitochondrial complexity index (MCI) and SDH_max relative to the nuclear membrane. Within each shell, SDH_max and MVD peaked in the perinuclear compartments and decreased toward the distal compartments of the cell. When normalized to mitochondrial volume, SDH_max decreased in the perinuclear compartments compared with distal compartments. TNFα caused a significant shift in mitochondrial morphometry and function compared to control. In conclusion, mitochondria within individual cells exhibit distinct morphological and functional heterogeneity, which is disrupted during acute inflammation.<b>NEW & NOTEWORTHY</b> Mitochondria show context-specific heterogeneity in their morphometry. Previously, we reported that acute TNFα exposure increased O₂ consumption rate (OCR) and mitochondrial volume density, but decreased OCR per mitochondrion. TNFα also altered mitochondrial distribution and motility. To assess TNFα-mediated subcellular mitochondrial structural and functional heterogeneity, we used a confocal-based quantitative histochemical technique to determine the maximum velocity of succinate dehydrogenase reaction. Our findings highlight that mitochondria within cells exhibit functional heterogeneity, which is disrupted during inflammation.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":"328 6","pages":"L792-L808"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12135700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956034","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":"Lumacaftor inhibits channel activity of rescued F508del cystic fibrosis transmembrane conductance regulator.","authors":"Adam D Ambrosetti, Zachary J Hagedorn, Taylor R Bono, Hui Wen, Rodney Nguyen, Kevin Rodriguez-Cruz, Judge Ali, Hayes Palacio, Aubrey J Phillips, Stephanie D Gilliland, Alana J Freeman, Jake Thompson, Lianwu Fu, Carmel M McNicholas, Steven M Rowe, X Robert Wang","doi":"10.1152/ajplung.00287.2024","DOIUrl":"10.1152/ajplung.00287.2024","url":null,"abstract":"<p><p>Lumacaftor, the corrector of Orkambi, enhances the processing of F508del cystic fibrosis transmembrane conductance regulator (CFTR), but its impact on the channel activity of rescued F508del CFTR (rF508del) is unclear. Using an electrode-based, real-time iodide efflux assay performed at room temperature, acute exposure to lumacaftor was shown to increase the processing of F508del CFTR without a proportional increase in channel activity in a CFBE41o-cell line stably expressing F508del CFTR (CFBE-DF). A similar effect was not observed on wild-type CFTR in a HEK293 cell line. At 37°C, rF508del channel activity is significantly inhibited in CFBE-DF cells by acute exposure to 5 µM lumacaftor, but not to 5 µM tezacaftor or 1 µM elexacaftor, the two correctors of Trikafta. Lumacaftor's inhibitory effect was characterized by a major left shift of the peak channel activity relative to the peak CFTR processing in the dose-response chart, which is absent for tezacaftor or elexacaftor. Ussing chamber analysis on polarized CFBE-DF cells reveals an inhibitory effect for lumacaftor on the forskolin- and ivacaftor-induced change in short-circuit current. Single channel patch clamp on HEK-DF cells shows that acute application of cytosolic lumacaftor significantly decreases rF508del channel open probability. Taken together, despite its strong corrector activity, lumacaftor inhibits rF508del channel activity, compromising the degree of functional rescue. This effect may contribute to the limited clinical efficacy of Orkambi.<b>NEW & NOTEWORTHY</b> Small-molecule correctors bind to F508del cystic fibrosis transmembrane conductance regulator (CFTR) and restore its trafficking to the plasma membrane to function as an anion channel. Despite its high efficacy as a corrector, lumacaftor inhibits the channel opening of rescued F508del CFTR, making it a weak CFTR modulator. The current work highlights the impact of CFTR correctors on the channel activity of rescued F508del CFTR as an important variable in the efficacy of modulator therapy.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L832-L843"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12173061/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956909","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":"Protocol for differentiating primary human small airway epithelial cells at the air-liquid interface.","authors":"Yu Par Aung Myo, Sarah V Camus, Margaret A T Freeberg, Tytus Bernas, Divya Bande, Rebecca L Heise, Thomas H Thatcher, Patricia J Sime","doi":"10.1152/ajplung.00380.2024","DOIUrl":"10.1152/ajplung.00380.2024","url":null,"abstract":"<p><p>The air-liquid interface (ALI) culture is an important tool in pulmonary research as it models the physiological lung where the epithelium is apically exposed to air and basally to the endothelium and interstitium. Although there is an abundance of research that uses primary human bronchial epithelial cells (HBECs) to study larger airways, small airway epithelial cells (SAECs) are an untapped resource in comparison. Primary SAECs are a valuable cell population as they enable the study of pathologies in the bronchioles and are also a favorable surrogate for primary alveolar epithelial cells, which are invasive to collect from patients. Currently, there are limited resources on how to culture and differentiate SAECs at the ALI. Here, we provide an optimized, detailed protocol to address this knowledge gap. Key culture conditions that determine the quality and uniformity of differentiated SAECs include cell passage number, pH changes caused by media exhaustion and incubator CO₂, seeding density, and collagen coating of the expansion flask and inserts. We also describe a FITC-dextran permeability assay to measure SAEC barrier integrity both as a pretest to select uniform wells with strong barrier integrity before an experiment and as a post-test to evaluate treatment effects afterward. The utility of the differentiated SAEC ALI model to ask biologically relevant questions is demonstrated by increased cytokine (IL-8, MIF, and CXCL-10) production and/or epithelial damage following exposure to cigarette smoke, lipopolysaccharide (LPS) or poly(I:C).<b>NEW & NOTEWORTHY</b> SAECs are not commonly used in pulmonary research, and this is reflected in a lack of literature on both SAEC primary research and methodological reports. Primary SAECs are an important resource as they enable the study of the small airways, which are implicated in a variety of pulmonary diseases, including chronic obstructive pulmonary disease (COPD). The detailed protocol described here bridges the knowledge gap on how to successfully differentiate primary human SAECs at the ALI.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":"328 6","pages":"L757-L771"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12169842/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143958235","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":"The cystathionine-γ-lyase inhibitor DL-propargylglycine augments the ability of L-cysteine ethyl ester to overcome the adverse effects of morphine on breathing.","authors":"Paulina M Getsy, Gregory A Coffee, Santhosh M Baby, Walter J May, Fraser Henderson, Zackery T Knauss, Stephen J Lewis","doi":"10.1152/ajplung.00003.2025","DOIUrl":"10.1152/ajplung.00003.2025","url":null,"abstract":"<p><p>l-cysteine ethyl ester (l-CYSee) overcomes adverse effects elicited by systemic injection of morphine on ventilatory parameters and arterial blood-gas chemistry in rats. l-CYSee or l-cysteine, resulting from the deesterification of l-CYSee, may enter enzymatic cascades that produce the ventilatory stimulant molecule, hydrogen sulfide (H₂S). dl-propargylglycine (dl-PROP) is an inhibitor of cystathionine-γ-lyase (CSE)-mediated conversion of l-cysteine to H₂S and has been widely used <i>in vivo</i>. We examined whether l-CYSee (2 injections × 500 µmol/kg, IV)-induced reversal of the changes in ventilation elicited by morphine (10 mg/kg, IV) in freely moving male Sprague Dawley rats was altered by prior administration of dl-PROP (25 mg/kg, IV). The major findings were <i>1</i>) the effects of morphine on ventilatory parameters were not affected by subsequent injection of dl-PROP; <i>2</i>) first injection of l-CYSee elicited a prompt reversal of the adverse effects of morphine that was more pronounced in dl-PROP-treated than vehicle-treated rats; and <i>3</i>) the actions of the second injection of l-CYSee were dramatically augmented in dl-PROP-treated rats. In addition, the changes in many of the ventilatory parameters during a subsequent hypoxic-hypercapnic (HH) gas challenge were augmented substantially by dl-PROP. This study demonstrates that <i>1</i>) inhibition of CSE with dl-PROP does not affect the ventilatory actions of morphine, <i>2</i>) reversal effects of l-CYSee were augmented by blockade of CSE, and <i>3</i>) blockade of CSE augments the ventilatory responses to HH gas challenge in morphine-treated rats. These unexpected findings suggest that the CSE-dependent production of H₂S from l-CYSee countermands l-CYSee reversal of morphine-induced respiratory depression in rats.<b>NEW & NOTEWORTHY</b> The ability of l-cysteine ethyl ester (l-CYSee) to overcome the adverse effects of morphine on breathing is exaggerated by inhibition of cystathionine-γ-lyase (CSE), suggesting that conversion of l-CYSee or l-cysteine to H₂S countermands the effects of l-CYSee against morphine.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":" ","pages":"L809-L825"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12199168/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143656035","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":"Transgenically expressed human delta epithelial sodium channel facilitated fluid absorption in mouse fetal lung explants.","authors":"Krishan G Jain, Runzhen Zhao, Jiwang Zhang, Hong-Long Ji","doi":"10.1152/ajplung.00028.2025","DOIUrl":"10.1152/ajplung.00028.2025","url":null,"abstract":"<p><p>Epithelial sodium channels (ENaCs) are essential for sodium (Na⁺) transport and maintaining fluid balance, which is vital for the removal of fetal fluid at birth and the homeostasis of luminal fluid in the lungs. In mice, ENaC is composed of three subunits (α, β, and γ). However, in humans, a fourth δ-subunit is also expressed. This study investigated the physiological role of the δ-ENaC in fetal/neonatal lungs, an area that remains less explored despite its potential significance. We measured expansion in mouse E15 lung explants expressing human δ-ENaC (SCNN1D-Tg). We found that transgenic expression of δ-ENaC enhanced fluid absorption and significantly reduced the surface area increase compared with wild-type (WT) explants (142.30 ± 5.81% vs. 163.80 ± 5.95% expansion, <i>P</i> < 0.001). Amiloride treatments revealed that both α-ENaC and δ-ENaC contributed to fluid absorption. No statistical significance was observed in the amiloride-sensitive fraction of SCNN1D-Tg explants compared with WT preparations in the presence of 100 µM amiloride (<i>P</i> = 0.400). In contrast, a significant reduction in amiloride-sensitive fraction in SCNN1D-Tg explants was observed in the presence of 10 µM amiloride (<i>P</i> < 0.001). Furthermore, specific blocking of α-ENaC using α-13 inhibitory peptide resulted in a 2.12-fold growth increase in WT explants, compared with a 1.47-fold increase in SCNN1D-Tg explants (<i>P</i> < 0.001). In summary, this study provides evidence that δ-ENaC may contribute to fluid absorption in E15 and newborn lungs, highlighting its significance in alveolar fluid regulation in prenatal and postnatal lungs.<b>NEW & NOTEWORTHY</b> The findings of our study highlight the significance of δ-ENaC in lung fluid regulation. Transgenic expression of human δ-ENaC contributes to fluid absorption increase, supporting its potential as a pathway for alveolar fluid clearance in E15 and postnatal lungs.</p>","PeriodicalId":7593,"journal":{"name":"American journal of physiology. Lung cellular and molecular physiology","volume":"328 6","pages":"L785-L791"},"PeriodicalIF":3.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12124468/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144061938","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}