Luczak J, Milek O, Carter H
… +6 more, Schafer CM, Ainsua-Enrich E, Griffin CT, Walters MS, Kovats S, Alberola-Ila J
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089345
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Invariant natural killer T (iNKT) cells play a critical role in the early phases of the response to Influenza A virus (IAV) infection by influencing inflammation and immune regulation, but the impact of the different iNK...Invariant natural killer T (iNKT) cells play a critical role in the early phases of the response to Influenza A virus (IAV) infection by influencing inflammation and immune regulation, but the impact of the different iNKT functional subsets (iNKT1, iNKT2, and iNKT17) in these responses is unclear. We used genetically altered mouse strains with normal numbers of iNKT cells, but different iNKT subset representation (NKTWT and NKTET2) to analyze the impact of different iNKT functional subsets on IAV infection outcomes. We show that IAV-infected NKTET2 mice have reduced weight loss, diminished myeloid recruitment and activation, and a 40% reduction in lung-infected areas compared with controls. This was accompanied by lower expression of inflammatory mediators (Ifna, Isg15, Ifit1) and chemoattractants Ccl2 and Cxcl2, along with elevated levels of type III interferon (Ifnl3). scRNAseq analysis of iNKTs suggests that these changes are driven by quantitative differences in iNKT responses, which are predominantly type I in NKTWT mice but type 17 in NKTET2 mice. These differences correlate with higher levels of Il22b and Il1b in NKTET2 mice lungs. Altogether our results indicate that changes in iNKT subset representation impact the outcome of IAV infections by changing the character of the early immune response.
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089343
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Lymphangioleiomyomatosis (LAM) is a rare, progressive lung disease that predominantly affects women, particularly during their reproductive years. It is characterised by the proliferation of abnormal smooth muscle-like c...Lymphangioleiomyomatosis (LAM) is a rare, progressive lung disease that predominantly affects women, particularly during their reproductive years. It is characterised by the proliferation of abnormal smooth muscle-like cells that infiltrate the lungs, leading to cystic destruction of lung tissue and a decline in respiratory function. The pathogenic defect in LAM occurs due to mutations in the tuberous sclerosis complex (TSC) genes, resulting in failure to suppress the mechanistic target of rapamycin (mTOR) pathway activation, which drives abnormal cell proliferation and lymphangiogenesis. Although mTOR inhibitors, such as sirolimus, have improved clinical management by slowing disease progression, they are not curative and do not reverse existing lung damage. Recent research has expanded our understanding of LAM pathogenesis by revealing substantial genetic and cellular heterogeneity within LAM lesions. Beyond mTOR dysregulation, pathways involving estrogen signalling, metabolic adaptation, and immune evasion contribute to disease development. These insights open new avenues for treatment. A better understanding of these pathways will pave the way for more durable and individualised treatments for LAM.
Eldredge LC, Han Y, Deutsch GH
… +9 more, Sucre JMS, Shirazi SP, Stefani C, Pribitzer S, Reeves SR, Rich LM, Vanderwall ER, Ziegler SF, Debley JS
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089342
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RATIONALE: Bronchopulmonary Dysplasia (BPD) arises from disrupted lung development after preterm birth and produces structural deficits at every level of the respiratory tree. Lower airway disease is emerging as a clinic...RATIONALE: Bronchopulmonary Dysplasia (BPD) arises from disrupted lung development after preterm birth and produces structural deficits at every level of the respiratory tree. Lower airway disease is emerging as a clinically significant BPD phenotype with increased mortality, yet the molecular mechanisms whereby preterm birth disrupts airway development remain poorly defined. OBJECTIVES: To develop a human model of lower airway disease following preterm birth and to define a molecular endotype of evolving BPD (eBPD) at baseline and in response to injury. METHODS: An ex vivo organotypic Airway Epithelial Cell (AEC) model was combined with well-characterized pathologic and transcriptomic patient samples for quantitative immunohistochemistry and RNA sequencing analyses. MEASUREMENTS AND MAIN RESULTS: Compared to AECs from healthy controls, eBPD-derived AECs exhibited reduced proliferation, impaired differentiation to ciliated epithelium, and expansion of a vimentin-positive population with a transcriptional profile associated with impaired AEC differentiation. Following hyperoxia exposure, eBPD-derived AECs mounted a robust vimentin response ex vivo, paralleling increased vimentin expression observed in airway cells from lung tissue of human infants with BPD. CONCLUSIONS: Using an organotypic model of neonatal airway differentiation, we demonstrate eBPD is associated with impaired AEC differentiation, increased vimentin-expression and concomitant loss of ciliated cells, and an exaggerated vimentin response to hyperoxic injury. These findings mimic the effects of prematurity in airway cells in human patients. These data support a mechanism whereby hyperoxia leads to impaired epithelial differentiation and associated lower airway dysfunction in BPD and inform future mechanistic studies interrogating the role of intermediate filaments in maladaptive epithelial repair.
Lin MT, Alexeyev M, Körbelin J
… +15 more, Zhou C, Chaney SD, Choi CS, Shastri C, Chavarria-Bernal HD, Chen NH, Stone M, Bauman AJ, Ayers L, Stevens RP, Lee JY, Sayner SL, Balczon R, Nelson AR, Stevens T
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089335
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Cytopathic tau variants are recovered from the lung, circulation, and brain following lower respiratory tract infection. Cytopathic tau injures the lung and brain, yet its cellular origin during infection is unknown. Her...Cytopathic tau variants are recovered from the lung, circulation, and brain following lower respiratory tract infection. Cytopathic tau injures the lung and brain, yet its cellular origin during infection is unknown. Here, we assessed whether lung capillary endothelium is a source of cytopathic tau that contributes to brain injury during infection. Alveolar-capillary permeability was higher in tau knockout than wild type mice following sublethal Pseudomonas aeruginosa infection, indicating endogenously expressed tau contributes to integrity of the lung's gas exchange unit. Hippocampal long-term potentiation was inhibited following sublethal infection in wild type but not tau knockout mice, even though the blood-brain barrier was not overtly disrupted. Tau expression solely in lung capillaries of tau knockout mice was sufficient to restore alveolar-capillary barrier integrity and impair hippocampal long-term potentiation following sublethal infection. Thus, endogenous lung capillary endothelial tau preserves alveolar-capillary integrity, yet it is a source of cytopathic tau that injures the brain during pneumonia.
Wohlgemuth K, Rasteiro M, Aneja M
… +22 more, Bota C, Cindric S, Freischem S, George S, Günsel GG, Ishola S, Koenig J, Kubisch-Dohmen R, Langenickel T, Loges NT, Lopes M, Mummert V, Olbrich H, Pennekamp P, Pereira T, Pinto AL, Raidt J, Rudolph C, Ter Steege A, Valecha D, Lopes SS, Omran H
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089334
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Primary Ciliary Dyskinesia (PCD) is a genetically heterogeneous disorder leading to destructive airway disease with severe bronchiectasis and chronic lung failure in adulthood. Pathogenic variants in CCDC40 are associate...Primary Ciliary Dyskinesia (PCD) is a genetically heterogeneous disorder leading to destructive airway disease with severe bronchiectasis and chronic lung failure in adulthood. Pathogenic variants in CCDC40 are associated with more severe reduction of lung function compared to most other PCD types. Currently, no therapies correcting the underlying disease mechanism are available. Here we investigate the efficacy of lipidoid nanoparticle-formulated mRNA encoding human CCDC40 (LNP-CCDC40-mRNA) as a corrective measure for structural and functional defects in vitro (human cells) and in vivo (zebrafish). Human nasal respiratory epithelial cells cultured at air-liquid-interface from five CCDC40-deficient individuals and a newly generated vertebrate animal model (ccdc40-/- zebrafish) were treated with LNP-CCDC40-mRNA. CCDC40-deficient cells were analyzed by high-speed video microscopy and immunofluorescence microscopy. ccdc40-/- zebrafish olfactory pit cilia were analyzed by high-speed video microscopy and fluid flow assays. Topical application of exogenous LNP-CCDC40-mRNA to CCDC40-deficient cells results in endogenous CCDC40 expression (10-74% of ciliated cells), enabling axonemal integration of CCDC40-associated proteins (CCDC39, GAS8/DRC4, DNALI1). Consistently, ciliary beat frequencies were significantly increased in treated CCDC40-deficient cells and comparable to healthy control cells. Further, we showed improved ciliary transport of fluorescent particles. Injection or topical application of human LNP-CCDC40-mRNA to ccdc40-/- zebrafish significantly increased ciliary motility and established directional flow in olfactory pits. We provide structural and functional evidence in vitro and in vivo for the biological efficacy of LNP-CCDC40-mRNA in CCDC40-deficient respiratory cells and zebrafish. Based on our results, an in vivo human study (Phase 1 trial) is planned in individuals with pathogenic variants in CCDC40.
Xue J, Nian M, Liang Y
… +8 more, Qi R, Hu Z, Zhao T, Cao X, Jia Y, Hou J, Chi S, Chen J
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089332
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Neutrophil extracellular trap (NET) formation has been implicated in the pathogenesis of rheumatoid arthritis-associated interstitial lung disease (RA-ILD), yet the specific neutrophil subsets involved and the mechanisms...Neutrophil extracellular trap (NET) formation has been implicated in the pathogenesis of rheumatoid arthritis-associated interstitial lung disease (RA-ILD), yet the specific neutrophil subsets involved and the mechanisms remain incompletely understood. Here, we identified a significantly expanded population of microsomal glutathione S-transferase 2-high NET-releasing polymorphonuclear neutrophils (Mgst2hi PMNs) in the lungs, bronchoalveolar lavage fluid (BALF), and peripheral blood (PB) of zymosan A-induced interstitial pneumonia-arthritis mouse models. Pharmacologic inhibition of Mgst2 with coniferyl ferulate (CF) and genetic knockdown using an adeno-associated virus (AAV9)-delivered shRNA under the Cd11b promoter (AAV9-shRNA-Mgst2) markedly attenuated pulmonary progression by suppressing NET formation. Mechanistically, Mgst2 promoted NET release in neutrophil-differentiated HL-60 cells and primary human peripheral blood neutrophils from healthy donors through a NADPH oxidases 2 (NOX2)-dependent pathway. NETs derived from these cells induced transdifferentiation of primary human pulmonary microvascular pericytes into myofibroblasts by activating transforming growth factor-beta (TGF-β) pathway. Clinically, circulating Mgst2hi NET-releasing PMNs were significantly elevated in the PB of patients with RA-ILD. Of note, more abundant Mgst2hi PMNs were found in RA patients with nonspecific interstitial pneumonia (NSIP) than those with usual interstitial pneumonia (UIP), organizing pneumonia (OP) and other ILD patterns. Moreover, the proportion of circulating Mgst2hi PMNs positively correlated with RA-NSIP severity, as assessed by and mean lung vessel diameter (6 mm), fibrosis score, and vessel score. Collectively, these findings demonstrate a critical pathogenic role for Mgst2hi PMNs in RA-ILD and suggest their utility as a potential therapeutic target through modulation of NET formation.
Sammani S, Bermudez T, Kempf CL
… +17 more, Casanova NG, Sun BL, Song JH, Hernandez A, Xu H, Canizales Galaviz J, Sun X, Dudek SM, Johnson NH, Camp SM, Fox C, Kinsey R, Miele S, Zhang DD, Bime C, Ooi A, Garcia JG
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089326
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Unremitting increases in lung vascular permeability is the pathophysiological hallmark of acute lung injuries (ALI) and drives both severity and mortality. Therapies with the capacity to quickly restore vascular integrit...Unremitting increases in lung vascular permeability is the pathophysiological hallmark of acute lung injuries (ALI) and drives both severity and mortality. Therapies with the capacity to quickly restore vascular integrity in ALI remains a serious unmet need. Our laboratory was first to report both the vascular barrier-protective effects of sphingosine-1 -phosphate (S1P) and S1P analogues, such as Tysiponate (TySIP), and the efficacy of peptide inhibitors (PIK) of non-muscle myosin light chain kinase (nmMLCK) as dual complementary strategies to reduce vascular permeability. The current study evaluates a novel nanocarrier (NTyP-100) containing conjugated TySIP and encargoed PIK as a pharmacologic approach to vascular barrier restoration in rodent models of LPS-induced ALI. NTyP-100 (or controls) was delivered IV to wild-type C57BL/6J mice exposed to a "one-hit" lipopolysaccharide (LPS, 18 h) ALI model or to Sprague-Dawley (SD) rats challenged by a "two-hit" ALI model combining LPS (18 h) and exposure to high tidal volume mechanical ventilation (MV, 4 h). Compared to TySIP or PIK alone, IV NTyP-100 produced the highest reduction (∼40%) in inflammatory injury in murine and rat ALI models (H&E, IHC p-MLC staining, BAL cells) with marked reductions in vascular leak (Evan Blue Dye leakage, BAL protein) and biochemical indices of inflammation. Genomic studies underscored NTyP-100 attenuation of ALI-mediated dysregulated barrier-regulatory signaling pathways (inflammatory response, innate immunity, TNF, IL-17, apoptosis). These studies demonstrate the successful therapeutic targeting of vascular barrier properties and supports the NTyP-100 nanocarrier as a strategy to address the unmet need for novel therapeutics that mitigate inflammatory injury and vascular permeability.
Cystic fibrosis (CF) is a common genetic disease caused by a defective CF-transmembrane conductance regulator (CFTR). People with CF (pwCF) are prone to develop infections by opportunistic pathogens, including Burkholder...Cystic fibrosis (CF) is a common genetic disease caused by a defective CF-transmembrane conductance regulator (CFTR). People with CF (pwCF) are prone to develop infections by opportunistic pathogens, including Burkholderia cenocepacia, leading to chronic inflammation. Neutrophils release granular proteins and oxidative products that contribute to tissue damage. CFTR modulators are a new treatment for pwCF aiming to correct the subcellular location and function of the CFTR ion channel. The triple modulator combination of Elexacaftor, Tezacaftor, and Ivacaftor (ETI) or Trikafta® has significantly improved clinical symptoms and overall provided a better quality of life for pwCF. The mechanism by which CFTR modulators help to restore the antimicrobial functions of neutrophils is unknown. The present study demonstrated that neutrophils functionally express CFTR and revealed how ETI modifies subcellular CFTR trafficking in CF neutrophils. In addition, ETI treatment reduced intracellular chloride levels in human neutrophils, indicating activation of CFTR-dependent chloride efflux. Finally, ETI treatment also re-established the intracellular antimicrobial killing of CF neutrophils by potentiating NADPH oxidase activity and improved trapping microbes by enhancing the production of Neutrophil Extracellular Traps (NETs). Together, our findings suggest that CFTR has an essential role in controlling neutrophil functions and CFTR modulators help restore the antimicrobial functions of neutrophils from pwCF.
Airway inflammation is a hallmark pathological feature of bronchial asthma and is closely associated with airway hyperresponsiveness. Pulmonary fibroblasts are key contributors to asthmatic inflammation, yet the underlyi...Airway inflammation is a hallmark pathological feature of bronchial asthma and is closely associated with airway hyperresponsiveness. Pulmonary fibroblasts are key contributors to asthmatic inflammation, yet the underlying mechanisms remain insufficiently defined. In this study, FK506 binding protein 51 (FKBP5) was significantly upregulated in fibroblasts from individuals with asthma, and its expression was positively correlated with disease severity. Genetic knockout of Fkbp5 reduced HDM-induced airway barrier disruption and inflammatory injury. Single-cell RNA sequencing showed that Fkbp5 knockout suppressed the expression of eosinophil-attracting chemokines and inflammatory cytokines in fibroblasts of asthmatic mice. Fibroblast-specific Fkbp5 knockout further confirmed its essential role in promoting airway inflammation. Mechanistically, FKBP5 facilitated MLKL-dependent necroptosis in fibroblasts, which enhanced the production of proinflammatory cytokines and eosinophil chemokines, disrupted immune homeostasis, and exacerbated airway inflammation. These findings identify FKBP5 in fibroblasts as a potential therapeutic target for asthma prevention and treatment.
Xie Y, Abel PW, Xing T
… +6 more, Zhong N, Jiang H, An SS, Panettieri RA, Casale TB, Tu Y
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089319
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Asthma, a chronic airway inflammatory disease, manifests as excessive obstruction of the airways and airway hyperresponsiveness (AHR) due to airway smooth muscle (ASM) contraction. Conventional bronchodilator treatments,...Asthma, a chronic airway inflammatory disease, manifests as excessive obstruction of the airways and airway hyperresponsiveness (AHR) due to airway smooth muscle (ASM) contraction. Conventional bronchodilator treatments, such as β2-adrenergic receptor (β2-AR) agonists, often lose efficacy due to receptor desensitization, while corticosteroid-resistant neutrophilic airway inflammation remains a major challenge in severe asthma. To identify novel bronchodilators, we screened the Sigma LOPAC1280 compound library using β2-agonist-desensitized precision-cut lung slices (PCLS) as an ex vivo model and identified pirfenidone (PFD), an FDA-approved drug for idiopathic pulmonary fibrosis, as a novel bronchodilator. We then developed CXN-8, a more potent PFD derivative. Both compounds produced rapid, concentration-dependent airway relaxation in human, mouse, and rat PCLS preconstricted with multiple bronchoconstrictors, and maintained efficacy under β2-AR-insensitive conditions. CXN-8 was ∼50-fold more potent than PFD while achieving comparable maximal relaxation, with EC50 values ranging from 0.8-4.7 μM across the different bronchoconstrictors. Mechanistically, PFD and CXN-8 suppressed RhoA-mediated Ca2 + sensitization by restoring myosin light chain phosphatase activity, which reduced phosphorylation of myosin regulatory light chain (MLC20) and promoted ASM relaxation. In vivo, acute oral administration of PFD (300 mg/kg) or CXN-8 (15 mg/kg) reduced airway resistance and AHR in house dust mite-sensitized mice. Chronic oral treatment (daily, Days 14-24) further attenuated airway inflammation and remodeling, decreasing eosinophil and neutrophil infiltration, Th2 and Th17 cytokines, ASM thickening, and peribronchial collagen deposition. Collectively, these findings identify PFD and CXN-8 as dual-acting bronchodilator and anti-inflammatory agents that also alleviate airway remodeling, offering a promising therapeutic strategy for β2-agonist-insensitive and corticosteroid-resistant asthma.
Pulmonary fibrosis poses a significant challenge in respiratory medicine, requiring innovative approaches and novel therapeutic strategies. This study explores the therapeutic potential of osteogenic growth peptide (OGP)...Pulmonary fibrosis poses a significant challenge in respiratory medicine, requiring innovative approaches and novel therapeutic strategies. This study explores the therapeutic potential of osteogenic growth peptide (OGP), an endogenous selective CB2 agonist, in a bleomycin-induced lung fibrosis model in both young and aged mice. Bleomycin (BLM) or saline was administered intratracheally. We injected OGP, saline, or hydrocortisone (positive control in young mice only) intraperitoneally daily from day 5 for 3 weeks (young mice) or 2 weeks (old mice). OGP significantly improved survival and reduced weight loss in BLM-treated mice. Histologically, OGP treatment significantly reduced the Ashcroft scale of disease severity, collagen content, and extracellular matrix (ECM) thickening in young and aged BLM-treated mice. Immunohistochemical analysis of alpha-smooth muscle actin (α-SMA) expression and gene expression profiling of key fibrotic markers also demonstrated a significant anti-fibrotic effect of OGP and its ability to mitigate myofibroblast activation in vivo. Overall, the beneficial impact of OGP was superior to that of hydrocortisone. We also performed an immunological profiling in old mice using flow cytometry. We found no significant differences in the numbers of T and myeloid cells, suggesting that OGP is not strictly immunosuppressive and it exerts specific anti-fibrotic actions on fibroblasts. Indeed, we found that OGP inhibits myofibroblast proliferation in murine primary cell cultures. This research demonstrates that OGP is a potent anti-fibrotic agent in both young and aged mice, with promising therapeutic potential in respiratory medicine.
Jiang Z, Xiao B, Hu Z
… +3 more, Li Y, Zhang H, Peng H
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089317
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BACKGROUND: This study aimed to investigate the role of the FBXW7/SPI1/MFAP4 axis in pulmonary arterial hypertension (PAH). METHODS: An in vivo PAH model was constructed using a hypoxia chamber. The expression levels of...BACKGROUND: This study aimed to investigate the role of the FBXW7/SPI1/MFAP4 axis in pulmonary arterial hypertension (PAH). METHODS: An in vivo PAH model was constructed using a hypoxia chamber. The expression levels of FBXW7, SPI1 and MFAP4 were detected by immunofluorescence and Western blotting. Cardiopulmonary function was assessed; pathological changes in lung tissue were examined by HE staining, and inflammatory factors levels were measured using ELISA. For in vitro studies, a PAH model was simulated using hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs). MFAP4-stable knockdown cells were constructed. Cell proliferation was evaluated with CCK8 and EdU assays, and cell migration was assessed using scratch wound and transwell assays. The targeting relationship between SPI1 and MFAP4 was verified by dual-luciferase reporter and ChIP-qPCR assays. Further, co-immunoprecipitation (Co-IP) and protein stability experiments were performed to confirm FBXW7-mediated ubiquitination of SPI1. RESULTS: In vivo, MFAP4 knockdown led to decreases in right ventricular systolic pressure (RVSP), mean pulmonary arterial pressure (mPAP), right ventricular (RV) contraction index, and pulmonary arterial (PA) wall thickness. In vitro, MFAP4 knockdown suppressed PASMC proliferation and migration. SPI1 was identified as an upstream transcription factor of MFAP4. FBXW7 was shown to promote SPI1 ubiquitination and its degradation in vitro. Overexpression of FBXW7 suppressed PAH progression both in vitro and in vivo, while simultaneous overexpression of either SPI1 or MFAP4 counteracted the protective effects of FBXW7 overexpression. CONCLUSION: Decreased FBXW7 expression in PAH inhibits SPI1 ubiquitination and protein degradation, leading to increased MFAP4 levels, which ultimately promotes PAH progression.
Lin L, Khoury J, Zhang G
… +3 more, Szafron J, Manning EP, Ahangari F
Am J Respir Cell Mol Biol
· 2026 Mar · PMID 42089315
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Idiopathic pulmonary fibrosis (IPF) is a progressive and often fatal lung disease characterized by the scarring and stiffening of lung tissue. While its exact cause remains elusive, emerging evidence underscores the sign...Idiopathic pulmonary fibrosis (IPF) is a progressive and often fatal lung disease characterized by the scarring and stiffening of lung tissue. While its exact cause remains elusive, emerging evidence underscores the significant role of mechanical forces and aberrant epithelial responses in its pathogenesis. The airway epithelium serves as a critical barrier and regulator of lung function, exhibiting abnormal responses to mechanical stress. Recent studies suggest that the abnormal airway epithelial response to mechanical stressors contributes to the progression of IPF and serves as an early indicator of disease onset. Understanding the complex interplay between mechanical forces and these cells in IPF not only sheds light on disease mechanisms but also opens avenues for novel therapeutic interventions targeting these pathways. The goal of this review is to highlight the most recent advances in understanding mechanobiology and the interaction between biomechanical properties and the airway epithelium in the pathogenesis of IPF. We seek to describe a positive feedback loop underlying pulmonary fibrosis, in which pro-fibrotic mechanobiological responses of airway epithelial cells drive biomechanical alterations in the lung airways. In parallel, these biomechanical changes further stimulate pro-fibrotic responses in the epithelial cells, perpetuating the cycle. Additionally, we aim to provide a comprehensive perspective on the role of lung biomechanics in the progression of fibrosis, emphasizing the critical need to disrupt this insidious feedback loop to halt or prevent the advancement of lung fibrosis.