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High-altitude and marine mammals inhabit distinct ecosystems but share a common challenge: hypoxia. To survive in low-oxygen environments, these species have evolved similar phenotypic pulmonary adaptations, characterized by a high density of elastic fibers. In this study, we explored the molecular mechanisms underlying these adaptations, focusing on pulmonary fibrosis and hypoxia tolerance through comparative genomics and convergent evolution analyses. We observed significant expansions and contractions in certain gene families across both high-altitude and marine mammals, closely associated with processes involved in pulmonary fibrosis. Notably, members of the keratin gene family, such as KRT17 and KRT14 , appear to be associated with the development of the dense elastic fiber phenotype observed in the lungs of hypoxia-tolerant mammals. Through selection pressure and amino acid substitution analyses, we identified multiple genes exhibiting convergent accelerated evolution, positive selection, and amino acid substitution in these species, associated with adaptation to hypoxic environments. Specifically, the convergent evolution of ZFP36L1 , FN1 , and NEDD9 was found to contribute to the high density of elastic fibers in the lungs of both high-altitude and marine mammals, facilitating their hypoxia tolerance. Additionally, we identified convergent amino acid substitutions and gene loss events associated with sperm development, differentiation, and spermatogenesis, such as amino acid substitutions in SLC26A3 and pseudogenization of CFAP47 , as confirmed by PCR. These genetic alterations may be linked to changes in the reproductive capabilities of these animals. Overall, this study offers novel perspectives on the genetic and molecular adaptations of high-altitude and marine mammals to hypoxic environments, with a particular emphasis on pulmonary fibrosis.

Background: Interferon regulatory factor-1 (IRF1) is a transcription factor that plays a significant role in various biological processes, including inflammatory injury, viral infection, cell death, and immune responses, and it has been extensively studied in the context of different lung diseases. However, the mechanism underlying its involvement in lung fibrosis remains largely unknown., Methods: Wild type (WT) mice, IRF1 global-null mice (Irf1 -/- ) were subjected to a bleomycin-induced lung fibrosis model to enable examination of the role of IRF1 in lung fibrosis. Proteomic analysis of lung tissue from WT and Irf1 -/- mice treated with saline or bleomycin was performed to explore the mechanism of IRF1 in regulating lung fibrosis., Results: In the bleomycin-induced fibrosis mouse model, increased expression of IRF1 was observed. Irf1 knockout mice displayed decreased lung fibrosis relative to WT mice following treatment with bleomycin. The protein expression of fibronectin, as assessed by the Western blot analysis of lung tissues, was downregulated in Irf1 -/- mice. We observed a similar reduction in collagen content using hydroxyproline detection. Histologically, there was less collagen deposition in the lungs of Irf1 -/- mice compared with WT mice. Proteomics data revealed that IRF1 may be involved in lung fibrosis via the regulation of ferroptosis. We determined that paraoxonase 1(PON1), a poorly characterized protein in lung fibrosis, was upregulated in Irf1 -/- mice following exposure to bleomycin. In vitro experiments revealed that IRF1 could regulate the level of GSH and MDA through PON1. We also determined that PON1 levels were lower in the plasma of IPF patients compared with healthy controls., Conclusion: Our data highlight the importance of IRF1 in the fibrotic process, and PON1 may be a potential mediator of IRF1 in the progression of lung fibrosis., (© 2024. The Author(s).)

Fine particulate matter (PM 2.5 ) has been identified as a significant contributing factor to the exacerbation of chronic obstructive pulmonary disease (COPD). It has been observed that PM 2.5 may induce lung fibrosis in COPD, although the precise molecular mechanism behind this remains unclear. In a previous study, we demonstrated that PM 2.5 upregulates oxidative stress induced growth inhibitor 1 (OSGIN1), which in turn leads to injury in airway epithelial cells, thereby, suggesting a potential link between PM 2.5 exposure and COPD. Based on this, we hypothesized that OSGIN1 plays a role in PM 2.5 -induced fibrosis in COPD. Human bronchial epithelial cells (HBEs) were treated with cigarette smoke extract (CSE) to construct an in vitro model of COPD. Our findings revealed that PM 2.5 increased fibrosis indicators and upregulated OSGIN1 in CSE-stimulated HBEs (CSE-HBEs), and knockdown of OSGIN1 reduced the expression of fibrosis indicators. Through the use of microRNA target prediction software and the Gene Expression Omnibus database, we predicted miRNAs that targeted OSGIN1 in COPD. Subsequently, real-time polymerase chain reaction and western blot analysis confirmed that PM 2.5 modulated miR-654-5p to regulate OSGIN1 in CSE-HBEs. Western blot demonstrated that OSGIN1 induced autophagy, thereby exacerbating fibrosis in CSE-HBEs. In summary, our results suggest that PM 2.5 upregulates OSGIN1 through inhibiting miR-654-5p, leading to increased autophagy and fibrosis in CSE-HBEs., Competing Interests: Declaration of Competing Interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The role and detailed mechanisms of lncRNAs in idiopathic pulmonary fibrosis (IPF) are not fully understood. qPCR was conducted to verify lncRNA FEZF1-AS1 expression in the transforming growth factor-beta 1 (TGF-β1)-stimulated human lung fibroblasts (HLF) and A549. The EMT-related proteins were performed by western blotting. Cell proliferation, migration, and transition were detected by CCK-8, colony formation, wound-healing and transwell assays. A dual-luciferase reporter assay was conducted to validate the target relationship of FEZF1-AS1 and miR-200c-3p. FEZF1-AS1 is highly expressed in the fibrotic A549 and HLF. in vitro experiments revealed that FEZF1-AS1 facilitates cell proliferation, migration and invasion. Knockdown of FEZF1-AS1 attenuated TGF-b1-induced fibrogenesis both in vitro. Moreover, silencing FEZF1-AS1 inhibited fibrogenesis through modulation of miR-200c-3p. In addition, inhibition of miR-200c-3p promoted fibrogenesis by regulation of Zinc finger E-box binding homeobox 1 (ZEB1). Mechanistically, FEZF1-AS1 promoted lung fibrosis by acting as a competing endogenous RNA (ceRNA) for miR-200c-3p. FEZF1-AS1 silencing increased the expression and activity of miR-200c-3p to inhibit ZEB1 and alleviate lung fibrogenesis in A549 and HLF. In addition, our study showed that FEZF1-AS1 can regulate enhancer of zeste homolog2 (EZH2) to upregulate fibrosis-related proteins and promote lung fibrosis. In summary, the results of our study revealed the pulmonary fibrogenic effect of FEZF1-AS1 in cellular experiments, demonstrating the potential roles and mechanisms of the FEZF1-AS1/miR-200c-3p/ZEB1 and FEZF1-AS1/EZH2 pathways, which provides a novel and potential therapeutic target to lung fibrosis., (© 2024. The Author(s).)

Background: Pulmonary fibrosis (PF) leads to excessive deposition of fibrous connective tissue in the lungs, increasing the risk of lung cancer due to the enhanced activity of fibroblasts (FBs). Fibroblast-mediated collagen fiber deposition creates a tumor-like microenvironment, laying the foundation for tumorigenesis. Clinically, numerous cases of lung cancer induced by pulmonary fibrosis have been observed. In recent years, the study of nucleotide point mutations, which provide more detailed insights than gene expression, has made significant advancements, offering new perspectives for clinical research., Methods: We initially employed Mendelian randomization to ascertain that the initial stage of lung cancer induced by PF belongs to small cell lung cancer (SCLC). Subsequently, pulmonary neuroendocrine cells (PNECs) were identified by using pseudo-time series analysis as cell clusters with carcinogenic potential. We categorized FBs into four groups according to their cellular metabolism, and then analyzed the cellular communication between FBs and PNECs, as well as changes in intracellular pathways of PNECs. Additionally, we examined the characteristic genome of FBs which is significantly associated with PF and investigated the impact of FBs on immune cells in the PF microenvironment. Finally, we explored strategies for preventing the progression from PF to lung cancer., Results: The genetic features of cells with carcinogenic potential in PF tissues were revealed, characterized by upregulation of Achaete-Scute Family BHLH Transcription Factor 1 (ASCL1), Homeobox B2 (HOXB2), Teashirt Zinc Finger Homeobox 2 (TSHZ2), Insulinoma-associated 1 (INSM1), and reduced activity of RE1 Silencing Transcription Factor (REST). FBs characterized by high glycolysis and low tricarboxylic acid (TCA) cycling played a key role in the progression of PF. The microenvironment of PF resembles the tumor microenvironment, providing a conducive immunosuppressive environment for the occurrence of cancer cells. In dendritic cells, rs9265808 is a susceptibility locus for progression from pulmonary fibrosis to lung cancer, mutations at this locus increase the expression of Complement Factor B (CFB), and excessive activation of the complement pathway is a crucial factor leading to lung cancer development in patients with pulmonary fibrosis. Ensuring adequate nutritional supply and physical function is one of the effective measures to prevent progression from pulmonary fibrosis to lung cancer., Conclusion: CFB promotes lung cancer occurrence by inducing the accumulation and polarization of a large number of monocytes/macrophages in the lungs, driving disease progression by reducing the physical fitness of patients with pulmonary fibrosis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Cell plasticity, changes in cell fate, is crucial for tissue regeneration. In the lung, failure of regeneration leads to diseases, including fibrosis. However, the mechanisms governing alveolar cell plasticity during lung repair remain elusive. We previously showed that PCLAF remodels the DREAM complex, shifting the balance from cell quiescence towards cell proliferation. Here, we find that PCLAF expression is specific to proliferating lung progenitor cells, along with the DREAM target genes transactivated by lung injury. Genetic ablation of Pclaf impairs AT1 cell repopulation from AT2 cells, leading to lung fibrosis. Mechanistically, the PCLAF-DREAM complex transactivates CLIC4, triggering TGF-β signaling activation, which promotes AT1 cell generation from AT2 cells. Furthermore, phenelzine that mimics the PCLAF-DREAM transcriptional signature increases AT2 cell plasticity, preventing lung fibrosis in organoids and mice. Our study reveals the unexpected role of the PCLAF-DREAM axis in promoting alveolar cell plasticity, beyond cell proliferation control, proposing a potential therapeutic avenue for lung fibrosis prevention., (© 2024. The Author(s).)

This study explores the role and potential mechanisms of microRNA-125b-5p (miR-125b-5p) in pulmonary fibrosis (PF). PF is a typical outcome of many chronic lung diseases, with poor prognosis and the lack of appropriate medical treatment because PF's molecular mechanisms remain poorly understood. In this study, using in vitro and in vivo analyses, we find that miR-125b-5p is likely a potent regulator of lung fibrosis. The findings reveal that, on the one hand, miR-125b-5p not only specifically decreases in the epithelial-mesenchymal transition (EMT) of lung epithelial cells, but also shows a downregulation trend in the lung tissues of mice with PF. On the other hand, overexpression of miR-125b-5p on the cellular and animal levels downregulates EMT and fibrotic phenotypes, respectively. To clarify the molecular mechanism of the "therapeutic" effect of miR-125b-5p, we use the target prediction tool combined with a dual luciferase assay and complete a rescue experiment by constructing the overexpression vector of the target gene Bcl-2 homologous antagonist/ killer (BAK1), thus confirming that miR-125b-5p can effectively inhibit EMT and fibrosis process by targeting BAK1 gene. MiR-125b-5p inhibits the EMT in lung epithelial cells by negatively regulating BAK1, while overexpression of miR-125b-5p can alleviate lung fibrosis. The findings suggest that MiR-125b-5p/BAK1 can serve as a potential treatment target for PF., (© 2024. The Author(s).)

Aberrant repair underlies the pathogenesis of pulmonary fibrosis while effective strategies to convert fibrosis to normal regeneration are scarce. Here, we found that thyroid hormone is decreased in multiple models of lung injury but is essential for lung regeneration. Moreover, thyroid hormone receptor α (TRα) promotes cell proliferation, while TRβ fuels cell maturation in lung regeneration. Using a specific TRβ agonist, sobetirome, we demonstrate that the anti-fibrotic effects of thyroid hormone mainly rely on TRβ in mice. Cellularly, TRβ activation enhances alveolar type-2 (AT2) cell differentiation into AT1 cell and constrains AT2 cell hyperplasia. Molecularly, TRβ activation directly regulates the expression of KLF2 and CEBPA, both of which further synergistically drive the differentiation program of AT1 cells and benefit regeneration and anti-fibrosis. Our findings elucidate the modulation function of the TRβ-KLF2/CEBPA axis on AT2 cell fate and provide a potential treatment strategy to facilitate lung regeneration and anti-fibrosis., (© 2024. The Author(s).)

Pulmonary fibrosis is characterized by excessive extracellular matrix (ECM) accumulation caused by detrimental stimuli. The progressive impairment in lung functions is chronic and highly fatal, presenting itself as a global health challenge. Because of the lack of efficacious treatments, the underlying mechanism should be investigated. The progression of fibrosis involves transforming growth factor-beta 1 (TGF-β1), which accelerates ECM production via epithelial-mesenchymal transition and cell invasion. As microRNAs (miRNAs) serve as regulators of disease development and progression, this study aimed to investigate the interaction of miRNAs and target genes that could contribute to pulmonary fibrosis when exposed to TGF-β1. Differentially expressed mRNA and miRNA were identified in respiratory epithelial cells via transcriptome analysis by using the constructed TGF-β1-induced fibrosis model. Our results revealed a significant increase in the expression of thrombospondin 1 (THBS1), which participates in TGF-β1 activation, where THBS1 was identified as a core gene in protein interactions analyzed through bioinformatics. The expression of miR-335-3p, which targets 3'-UTR of THBS1, substantially decreased upon TGF-β1 treatment. The TGF-β1 downstream signal was suppressed by inhibiting the interaction between TGF-β1 and THBS1, consequently alleviating fibrosis. When the miR-335-3p mimic was transfected in TGF-β1-treated respiratory epithelial cells, THBS1 and fibrosis markers were downregulated, while the introduction of miR-335-3p inhibitor exhibited a reverse phenomenon. Our findings demonstrated that TGF-β1 exposure to respiratory epithelial cells led to a decrease in miR-335-3p expression, resulting in the upregulation of THBS1 and ultimately exacerbating fibrosis. This study provides insights into TGF-β1-induced pulmonary fibrosis, suggesting new therapeutic targets and mechanisms., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Han et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: Acute respiratory distress syndrome (ARDS) patients currently have relatively high mortality, which is associated with early lung fibrosis. This study aimed to investigate whether miR-17 suppression could alleviate ARDS-associated lung fibrosis by regulating Mfn2., Methods: A mouse model of ARDS-related lung fibrosis was constructed via intratracheal instillation of bleomycin. The expression level of miR-17 in lung tissues was detected via quantitative real time polymerase chain reaction (qRT-PCR). In the ARDS mouse model of lung fibrosis, the mitigating effects of miR-17 interference were evaluated via tail vein injection of the miR negative control or the miR-17 antagomir. The pathological changes in the lung tissue were examined via HE staining and Masson's trichrome staining, and the underlying molecular mechanism was investigated via ELISA, qRT-PCR and Western blotting., Results: Bleomycin-induced pulmonary fibrosis significantly increased collagen deposition and the levels of hydroxyproline (HYP) and miR-17. Interfering with miR-17 significantly reduced the levels of HYP and miR-17 and upregulated the expression of Mfn2. The intravenous injection of the miR-17 antagomir alleviated lung inflammation and reduced collagen deposition. In addition, interference with miR-17 could upregulate LC3B expression, downregulate p62 expression, and improve mitochondrial structure., Conclusion: Interfering with miR-17 can improve pulmonary fibrosis in mice by promoting mitochondrial autophagy via Mfn2., (© 2024. Huazhong University of Science and Technology.)

Lung cancer is the leading cause of cancer-related deaths worldwide. Patients with lung cancer usually exhibit poor prognoses and low 5-year survival rates. Idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) are both chronic lung dysfunctions resulting in lung fibrosis and increased risk of lung cancer. Myofibroblasts contribute to the progression of asthma, COPD and IPF, leading to fibrosis in the airway and lungs. A growing body of evidence demonstrates that metabolic reprogramming is a major hallmark of fibrosis, being important in the progression of fibrosis. Using gene expression microarray, we identified and validated that the lipid metabolic pathway was upregulated in lung fibroblasts upon interleukin (IL)-4, IL-13 and tumour necrosis factor (TNF)-α treatment. In this study, we described that prostaglandin E synthase (PTGES) was upregulated in lung fibroblasts after IL-4, IL-13 and TNF-α treatments. PTGES increased α-SMA levels and promoted lung fibroblast cell migration and invasion abilities. Furthermore, PTGES was upregulated in a lung fibrosis rat model in vivo. PTGES increased AKT phosphorylation, leading to activation of the HIF-1α-glycolysis pathway in lung fibroblast cells. HIF-1α inhibitor or 2-DG treatments reduced α-SMA expression in recombinant PTGES (rPTGES)-treated lung fibroblast cells. Targeting PGE 2 signalling in PTGES-overexpressing cells by a PTGES inhibitor reduced α-SMA expression. In conclusion, the results of this study demonstrate that PTGES increases the expression of myofibroblast marker via HIF-1α-dependent glycolysis and contributes to myofibroblast differentiation., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease. N6-methyladenosine (m 6 A) is a reversible RNA modification that was shown to be associated with IPF development. The present study aimed to explore the function and potential mechanism of the m 6 A methylation enzyme zinc finger CCCH-type containing 13 (ZC3H13) in IPF. In the study, bioinformatic screening yielded a differentially expressed m 6 A gene, ZC3H13, which was down-regulated in GEO microarrays, BLM-induced mouse models, and cellular models. Overexpression of ZC3H13 reduced histopathological damage of lung tissues in mice, mitigated fibrosis (including reduced α-SMA, collagen Ⅰ, and Vimentin levels, and elevated E-cadherin levels), decreased lung/body weight ratio and lung hydroxyproline levels, reduced oxidative stress (increased SOD activity and GSH-Px activity and decreased MDA levels), suppressed apoptosis within lung tissues and MLE-12 cells, promoted Bcl-2 expression, and inhibited Bax expression. Bax expression was found to be negatively correlated with ZC3H13 expression by correlation analysis. ZC3H13 could bind Bax mRNA and promote its m 6 A methylation through reading protein YTHDC1, thereby inhibiting its stability. Bax inhibition ameliorated BLM-induced MLE-12 cell dysfunction and partially abrogated the inhibition of MLE-12 cell function by ZC3H13 downregulation. In conclusion, m 6 A methyltransferase ZC3H13 impedes lung epithelial cell apoptosis and thus improves pulmonary fibrosis by promoting Bax mRNA m 6 A methylation and down-regulating Bax expression through reading protein YTHDC1., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Long non-coding RNAs play a key role in silicosis, a fatal fibrotic lung disease, and there is an urgent need to develop new treatment targets. Long intergenic non-protein-coding RNA 3047 (LINC03047) is associated with cancer, but its role and mechanism in the progression of silicosis require further elucidation. This study investigated the function of LINC03047 in the epithelial-mesenchymal transition (EMT) during silicosis progression. LINC03047 expression was upregulated in SiO 2 -treated BEAS-2B and A549 cells, promoting SiO 2 -induced ferroptosis and subsequent EMT. Moreover, knockdown of LINC03047 significantly decreased the expression of solute carrier family 39 member 14 (SLC39A14), a ferrous iron transporter, and inhibition of SLC39A14 alleviated the ferroptosis and EMT caused by LINC03047 overexpression. We further investigated that NF-κB p65 (RELA) was critical for LINC03047 transcription in SiO 2 -treated BEAS-2B and A549 cells. In vivo experiments showed that SLC39A14 deficiency improved SiO 2 -induced lipid peroxidation and EMT. Collectively, our study reveals the function of the RELA/LINC03047/SLC39A14 axis in SiO 2 -induced ferroptosis and EMT, thereby contributing to the identification of novel drug targets for silicosis therapy., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Fibrosis is characterized by excessive deposition of extracellular matrix proteins, particularly collagen, caused by myofibroblasts in response to chronic inflammation. Although G protein-coupled receptors (GPCRs) are among the targets of current antifibrotic drugs, no drug has yet been approved to stop fibrosis progression. Herein, we aimed to identify GPCRs with profibrotic effects. In gene expression analysis of mouse lungs with induced fibrosis, eight GPCRs were identified, showing a >2-fold increase in mRNA expression after fibrosis induction. Among them, we focused on Gpr176 owing to its significant correlation with a myofibroblast marker α-smooth muscle actin (αSMA), the profibrotic factor transforming growth factor β1 (TGFβ1), and collagen in a human lung gene expression database. Similar to the lung fibrosis model, increased Gpr176 expression was also observed in other organs affected by fibrosis, including the kidney, liver, and heart, suggesting its role in fibrosis across various organs. Furthermore, fibroblasts abundantly expressed Gpr176 compared to alveolar epithelial cells, endothelial cells, and macrophages in the fibrotic lung. GPR176 expression was unaffected by TGFβ1 stimulation in rat renal fibroblast NRK-49 cells, whereas knockdown of Gpr176 by siRNA reduced TGFβ1-induced expression of αSMA, fibronectin, and collagen as well as Smad2 phosphorylation. This suggested that Gpr176 regulates fibroblast activation. Consequently, Gpr176 acts in a profibrotic manner, and inhibiting its activity could potentially prevent myofibroblast differentiation and improve fibrosis. Developing a GPR176 inverse agonist or allosteric modulator is a promising therapeutic approach for fibrosis., Competing Interests: Declaration of competing interest H.I. is an employee of Maruho Co., Ltd. All other authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Integrative multiomics can help elucidate the pathophysiology of pulmonary fibrosis (PF)-associated pulmonary hypertension (PH) (PF-PH). Weighted gene coexpression network analysis (WGCNA) was performed on a transcriptomic dataset of explanted lung tissue from 116 patients with PF. Patients were stratified by pulmonary vascular resistance (PVR), and differential gene expression analysis was conducted. Gene modules were correlated with hemodynamics at the time of transplantation and tested for enrichment in the lung transcriptomics signature of an independent pulmonary arterial hypertension (PAH) cohort. We found 1,250 differentially expressed genes between high and low PVR groups. WGCNA identified that black and yellowgreen modules negatively correlated with PVR, whereas the tan and darkgrey modules are positively correlated with PVR in PF-PH. In addition, the tan module showed the strongest enrichment for an independent PAH gene signature, suggesting shared gene expression patterns between PAH and PF-PH. Pharmacotranscriptomic analysis using the Connectivity Map implicated the tan and darkgrey modules as potentially pathogenic in PF-PH, given their combined module signature demonstrated a high negative connectivity score for treprostinil, a medication used in the treatment of PF-PH, and a high positive connectivity score for bone morphogenetic protein (BMP) loss of function. Pathway enrichment analysis revealed that inflammatory pathways and oxidative phosphorylation were downregulated, whereas epithelial-mesenchymal transition was upregulated in modules associated with increased PVR. Our integrative systems biology approach to the lung transcriptome of PF with and without PH identified several PH-associated coexpression modules and gene targets with shared molecular features with PAH warranting further investigation to uncover potential new therapies for PF-PH. NEW & NOTEWORTHY An integrative systems biology approach that included transcriptomic analysis of explanted lung tissue from patients with pulmonary fibrosis (PF) with and without pulmonary hypertension (PH) undergoing lung transplantation, combined with hemodynamic correlation and pharmacotranscriptomics, identified modules of genes associated with pulmonary vascular disease severity. Comparison with an independent pulmonary arterial hypertension (PAH) dataset identified shared gene expression patterns between PAH and PF-PH.

The pathogenesis of SSc pulmonary fibrosis is complex and prognosis is poor. In order to find biomarkers to provide assistance in the diagnosis and treatment of systemic sclerosis (SSc), this study explored the role of SSc-related differentially expressed circRNAs in the fibrosis process. This study explored whether circular RNA (circRNA) mediated the mTOR signaling pathway by interacting with the eukaryotic translation initiation factor eIF4E-binding protein 1 (4E-BP1), participated in a competing endogenous RNA (ceRNA) network, and regulated the mechanism of pulmonary fibrosis in systemic sclerosis (SSc). The results showed that the expression of mmu_circ_0005373 was reduced, and mmu_circ_0005373 may regulate the mTOR signaling pathway by inhibiting the interacting with 4E-BP1 protein in the lung of SSc mice, and promote fibrosis in SSc. Hsa_circ_0136255, which is homologous to mmu_circ_0005373, is also reduced in SSc peripheral blood mononuclear cells, and predicted to interact with 4E-BP1 protein. Hsa_circ_0136255/hsa-miR-330-3p/TNFAIP3 ceRNA network had biological significance in SSc, and correlated with clinical data, including high-resolution CT, average expiratory flow at 25% vital capacity, neutrophil count, lymphocyte percentage, standard deviation of red blood cell distribution width, coefficient of variation of red blood cell distribution width, platelet distribution width, glutamic transaminase, γ-glutamyl transpeptidase, lymphocyte percentage, basophils percentage, red blood cell, plateletcrit, cholinesterase, and mean corpuscular hemoglobin concentration. Hsa_circ_0136255, hsa-miR-330-3p, and TNFAIP3 may be used as biomarkers for clinical diagnosis and treatment of SSc., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Idiopathic pulmonary fibrosis (IPF) is an age-related disease severely affecting life quality with its prevalence rising as the population ages, yet there is still no effective treatment available. Cell therapy has emerged as a promising option for IPF, however, the absence of mature and stable animal models for IPF immunodeficiency hampers preclinical evaluations of human cell therapies, primarily due to rapid immune clearance of administered cells. This study aims to establish a reliable pulmonary fibrosis (PF) model in immunodeficient mice that supports autologous cell therapy and to investigate underlying mechanism., Methods: We utilized thirty 5-week-old male NOD/SCID mice, categorizing them into three age groups: 12weeks, 32 weeks and 43 weeks, with 6 mice euthanized randomly from each cohort for lung tissue analysis. We assessed fibrosis using HE staining, Masson's trichrome staining, α-SMA immunohistochemistry and hydroxyproline content measurement. Further, β-galactosidase staining and gene expression analysis of MMP9, TGF-β1, TNF-α, IL-1β, IL-6, IL-8, SOD1, SOD2, NRF2, SIRT1, and SIRT3 were performed. ELISA was employed to quantify protein levels of TNF-α, TGF-β1, and IL-8., Results: When comparing lung tissues from 32-week-old and 43-week-old mice to those from 12-week-old mice, we noted a marked increase in inflammatory infiltration, fibrosis severity, and hydroxyproline content, alongside elevated expression levels of α-SMA and MMP9. Notably, the degree of fibrosis intensified with age. Additionally, β-galactosidase staining became more pronounced in older mice. Quantitative PCR analyses revealed age-related, increases in the expression of senescence markers (GLB1, P16, P21), and proinflammatory genes (TGF-β1, TNF-α, IL-1β, IL-6, and IL-8). Conversely, the expression of anti-oxidative stress-related genes (SOD1, SOD2, NRF2, SIRT1, and SIRT3) declined, showing statistically significant differences (*P < 0.05, **P < 0.01, ***P < 0.001). ELISA results corroborated these findings, indicating a progressive rise in the protein levels of TGF-β1, TNF-α, and IL-8 as the mice aged., Conclusions: The findings suggest that NOD/SCID mice aged 32 weeks and 43 weeks effectively model pulmonary fibrosis in an elderly context, with the disease pathogenesis likely driven by age-associated inflammation and oxidative stress., (© 2024. The Author(s).)

Idiopathic pulmonary fibrosis (IPF) is a progressive, often fatal lung disease characterized by tissue scarring and declining lung function. The MUC5B promoter polymorphism rs35705950, a significant genetic predisposition for IPF, paradoxically associates with better survival and slower disease progression than other IPF genotypes. This study investigates the potential paradoxical protective effects of this MUC5B variant in lung fibrosis. For this purpose, we developed a transgenic mouse model overexpressing the human MUC5B rs35705950 variant in the proximal large airways. Lung fibrosis was induced through subcutaneous injection of bleomycin. Results demonstrated significantly reduced lung fibrosis severity in transgenic mice compared to wild-type mice, assessed by trichrome staining, Ashcroft scoring, and hydroxyproline levels. Additionally, transgenic mice showed significantly lower levels of inflammatory cells and cytokines (TNFα, IL-6, IFNγ) and growth factors (PDGF, CTGF, IL-13) in the bronchoalveolar lavage fluid and lung tissues. There was also a significant decrease in mRNA expressions of fibrosis-related markers (periostin, fibronectin, Col1a1). In summary, this study reveals that mucin overexpression related to the MUC5B rs35705950 variant in the large airways significantly attenuates lung fibrosis and inflammatory responses in transgenic mice. These findings suggest that the rs35705950 variant modulates inflammatory and fibrotic responses in the proximal airways, which may contribute to the slower disease progression observed in IPF patients carrying this variant. Our study offers a possible explanation for the paradoxical beneficial effects of the MUC5B variant despite its role as a significant predisposing factor for IPF.

It is estimated that there are 544.9 million people suffering from chronic respiratory diseases in the world, which is the third largest chronic disease. Although there are various clinical treatment methods, there is no specific drug for chronic pulmonary diseases, including chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD) and idiopathic pulmonary fibrosis (IPF). Therefore, it is urgent to clarify the pathological mechanism and medication development. Single-cell transcriptome data of human and mouse from GEO database were integrated by "Harmony" algorithm. The data was standardized and normalized by using "Seurat" package, and "SingleR" algorithm was used for cell grouping annotation. The "Findmarker" function is used to find differentially expressed genes (DEGs), which were enriched and analyzed by using "clusterProfiler", and a protein interaction network was constructed for DEGs, and four algorithms are used to find the hub genes. The expression of hub genes were analyzed in independent human and mouse single-cell transcriptome data. Bulk RNA data were used to integrate by the "SVA" function, verify the expression levels of hub genes and build a diagnostic model. The L1000FWD platform was used to screen potential drugs. Through exploring the similarities and differences by integrated single-cell atlas, we found that the lung parenchymal cells showed abnormal oxidative stress, cell matrix adhesion and ubiquitination in COPD, corona virus disease 2019 (COVID-19), ILD and IPF. Meanwhile, the lung resident immune cells showed abnormal Toll-like receptor signals, interferon signals and ubiquitination. However, unlike acute pneumonia (COVID-19), chronic pulmonary disease shows enhanced ubiquitination. This phenomenon was confirmed in independent external human single-cell atlas, but unfortunately, it was not confirmed in mouse single-cell atlas of bleomycin-induced pulmonary fibrosis model and influenza virus-infected mouse model, which means that the model needs to be optimized. In addition, the bulk RNA-Seq data of COVID-19, ILD and IPF was integrated, and we found that the immune infiltration of lung tissue was enhanced, consistent with the single-cell level, UBA52, UBB and UBC were low expressed in COVID-19 and high expressed in ILD, and had a strong correlation with the expression of cell matrix adhesion genes. UBA52 and UBB have good diagnostic efficacy, and salermide and SSR-69071 can be used as their candidate drugs. Our study found that the disorder of protein ubiquitination in chronic pulmonary diseases is an important cause of pathological phenotype of pulmonary fibrosis by integrating scRNA-Seq and bulk RNA-Seq, which provides a new horizons for clinicopathology, diagnosis and treatment., (© 2024. The Author(s).)

Background: Idiopathic pulmonary fibrosis (PF) is a chronic progressive interstitial lung disease characterized by alveolar epithelial cell (AEC) injury and fibroblast activation. Inadequate autophagy in AECs may result from the activation of several signaling pathways following AEC injury, with glycoproteins serving as key receptor proteins. The core fucosylation (CF) modification in glycoproteins is crucial. Mesenchymal stem cells derived from bone marrow (BMSCs) have the ability to regenerate damaged tissue and treat PF. This study aimed to elucidate the relationship and mechanism of interaction between BMSCs, CF modification, and autophagy in PF., Methods: C57BL/6 male mice, AEC-specific FUT8 conditional knockout (CKO) mice, and MLE12 cells were administered bleomycin (BLM), FUT8 siRNA, and mouse BMSCs, respectively. Experimental techniques including tissue staining, Western blotting, immunofluorescence, autophagic flux detection, and flow cytometry were used in this study., Results: First, we found that autophagy was inhibited while FUT8 expression was elevated in PF mice and BLM-induced AEC injury models. Subsequently, CKO mice and MLE12 cells transfected with FUT8 siRNA were used to demonstrate that inhibition of CF modification induces autophagy in AECs and mitigates PF. Finally, mouse BMSCs were used to demonstrate that they alleviate the detrimental autophagy of AECs by inhibiting CF modification and decreasing PF., Conclusions: Suppression of CF modification enhanced the suppression of AEC autophagy and reduced PF in mice. Additionally, through the prevention of CF modification, BMSCs can assist AECs deficient in autophagy and partially alleviate PF., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Pulmonary fibrosis is a progressive disease with high incidence and poor prognosis. It is urgent to explore new therapeutic methods for pulmonary fibrosis. As a new treatment method, gene therapy has attracted more and more attention. CCDC59 is a transcriptional coactivator of SP-B and SP-C. Our study mainly aims to explore the effect of overexpression of CCDC59 gene in pulmonary fibrosis of mice., Methods: CCDC59 overexpressing lentivirus was constructed and then concentrated. RT-qPCR, Western blotting, and immunofluorescence assays were used to detect the expression of CCDC59, SP-B and SP-C protein in cell line and lung tissues after infected with lentivirus. Immunohistochemical staining and hematoxylin-eosin staining assays were used to assess the degree of fibrosis and ELISA assay was used to detect the concentrations of inflammatory factors, SP-B, and SP-C in bronchoalveolar lavage fluid of mice. Dynamic changes of mice lung function at various time points were assessed by lung function test assay. HIPPO pathway and proliferation capacity of alveolar type II epithelial cells were evaluated by immunofluorescence staining and Western blotting., Results: Results showed that endotracheal instillation of CCDC59 overexpressed lentivirus significantly alleviated bleomycin-induced inflammation and pulmonary fibrosis in mice. Overexpression of CCDC59 protein in type II alveolar epithelial cells can enhance the expression of SP-B and SP-C. Overexpression of CCDC59 protein significantly protected against pulmonary inflammatory response and improved lung function of mice. Overexpression of CCDC59 protein significantly alleviated the hyperactivation of HIPPO pathway and increased the proliferative capacity of type II alveolar epithelial cells in lung., Conclusion: CCDC59 can alleviate inflammation and pulmonary fibrosis in mice by upregulating the expression of SP-B and SP-C in type II alveolar epithelial cells and alleviating the hyperactivation of HIPPO pathway. Our study offers a new potential treatment for pulmonary fibrosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Harmine has many pharmacological activities and has been found to significantly inhibit the fibrosis of keloid fibroblasts. DNA damage repair (DDR) is essential to prevent fibrosis. This study aimed to investigate the effects of harmine on pulmonary fibrosis and its underlying mechanisms., Methods: Bleomycin and TGF-β1 were used to construct pulmonary fibrosis models in vivo and in vitro, then treated with harmine to explore harmine's effects in treating experimental pulmonary fibrosis and its related mechanisms. Then, RNA sequencing was applied to investigate further the crucial DDR-related genes and drug targets of harmine against pulmonary fibrosis. Finally, the expression levels of DDR-related genes were verified by real-time quantitative PCR (RT-qPCR) and western blot., Results: Our in vivo experiments showed that harmine treatment could improve weight loss and lung function and reduce tissue fibrosis in mice with pulmonary fibrosis. The results confirmed that harmine could inhibit the viability and migration of TGF-β1-induced MRC-5 cells, induce their apoptosis, and suppress the F-actin expression, suggesting that harmine could suppress the phenotypic transition from lung fibroblasts to lung myoblasts. In addition, RNA sequencing identified 1692 differential expressed genes (DEGs), and 10 DDR-related genes were screened as critical DDR-related genes. RT-qPCR and western blotting showed that harmine could down-regulate the expression of CHEK1, ERCC1, ERCC4, POLD1, RAD51, RPA1, TOP1, and TP53, while up-regulate FEN1, H2AX and GADD45α expression., Conclusions: Harmine may inhibit pulmonary fibrosis by regulating DDR-related genes and activating the TP53-Gadd45α pathway., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Silicosis is a systemic disease caused by long-term exposure to high concentrations of free silica dust particles in the workplace. It is characterized by a persistent inflammatory response, fibroblast proliferation, and excessive collagen deposition, leading to pulmonary interstitial fibrosis. Epithelial interstitial transformation (EMT) can cause epithelial cells to lose their tight junctions, cell polarity, and epithelial properties, thereby enhancing the properties of interstitial cells, which can lead to the progression of fibrosis and the formation of scar tissue. Integrin 1 (ITGB1) is considered an important factor for promoting EMT and tumor invasion in a variety of tumors and also plays an important role in the progression of fibrotic diseases. Therefore, ITGB1 can be used as a potential target for the treatment of silicosis. In this study, we found that silica exposure induced epithelial-mesenchymal transformation in rats and that the expression of integrin ITGB1 was elevated along with the EMT. We used CRISPR/Cas9 technology to construct integrin ITGB1 knockdown cell lines for in vitro experiments. We compared the expression of the EMT key proteins E-cadherin and vimentin in the ITGB1 knockdown cells and wild-type cells simultaneously stimulated by silica and detected the aggregation point distribution of E-cadherin and vimentin in the cells using laser confocal microscopy. Our results showed that ITGB1 knockout inhibited the ITGB1/ILK/Snail signaling pathway and attenuated the EMT occurrence compared to control cells. These results suggested that ITGB1 is associated with silica-induced EMT and may be a potential target for the treatment of silicosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive and chronic disease that significantly impacts patient quality of life, and its incidence is on the rise. The pathogenesis of IPF remains poorly understood. Alveolar type 2 (AT2) cells are crucial in the onset and progression of IPF, yet the specific mechanisms involved are not well defined. Lon protease 1 (LONP1), known for its critical roles in various diseases, has an unclear function in IPF. Our research investigated the impact of Lonp1 gene deletion on AT2 cell functionality and its subsequent effect on IPF development. We generated a bleomycin-induced pulmonary fibrosis mouse model with a targeted Lonp1 knockout in AT2 cells and assessed the consequences on AT2 cell function and fibrosis progression. Additionally, we constructed the MLE12 cells with stable Lonp1 knockdown and utilized transcriptome sequencing to identify pathways altered by the Lonp1 knockdown. Our results indicated that mice with AT2 cell-specific Lonp1 knockout exhibited more severe fibrosis compared to controls. These mice exhibited a reduction in AT2 and AT1 cell populations, along with an increase in p53- and p21-positive AT2 cells. Lonp1 knockdown in MLE12 cells led to the upregulation of aging-associated pathways, with fibroblast growth factor 2 (Fgf2) gene emerging as a central gene interconnecting these pathways. Therefore, loss of Lonp1 appears to promote AT2 cell aging and exacerbate bleomycin-induced pulmonary fibrosis. Fgf2 emerges as a pivotal downstream gene associated with cellular senescence. This study uncovers the role of the Lonp1 gene in pulmonary fibrosis, presenting a novel target for investigating the pathological mechanisms and potential therapeutic approaches for IPF.

Next-generation risk assessment (NGRA) has emerged as a promising alternative to non-animal studies owing to the increasing demand for the risk assessment of inhaled toxicants. In this study, NGRA was used to assess the inhalation risks of two biocides commonly used as humidifier disinfectants: polyhexamethylene guanidine phosphate (PHMG-p) and chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT). Human bronchial epithelial cell transcriptomic data were processed based on adverse outcome pathways and used to establish transcriptome-based points of departure (tPODs) for each biocide. tPOD values were 0.00500-0.0510 μg/cm 2 and 0.0342-0.0544 μg/cm 2 for PHMG-p and CMIT/MIT, respectively. tPODs may provide predictive power comparable to that of traditional animal-based PODs (aPODs). The tPOD-based NGRA determined that both PHMG-p and CMIT/MIT present a high inhalation risk. Moreover, the identified PHMG-p posed a higher risk than CMIT/MIT, and children were identified as more susceptible population compared to adults. This finding is consistent with observations from actual exposure events. Our findings suggest that NGRA with transcriptomics offers a reliable approach for risk assessment of specific humidifier disinfectant biocides, while acknowledging the limitations of current models and in vitro systems, particularly regarding uncertainties in pharmacokinetics (PK) and pharmacodynamics (PD)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose of Review: The identification of extra-pulmonary symptoms plays a crucial role in diagnosing interstitial lung disease (ILD). These symptoms not only indicate autoimmune diseases but also hint at potential genetic disorders, suggesting a potential overlap between genetic and autoimmune origins., Recent Findings: Genetic factors contributing to ILD are predominantly associated with telomere (TRG) and surfactant-related genes. While surfactant-related gene mutations typically manifest with pulmonary involvement alone, TRG mutations were initially linked to syndromic forms of pulmonary fibrosis, known as telomeropathies, which may involve hematological and hepatic manifestations with variable penetrance. Recognizing extra-pulmonary signs indicative of telomeropathy should prompt the analysis of TRG mutations, the most common genetic cause of familial pulmonary fibrosis. Additionally, various genetic diseases causing ILD, such as alveolar proteinosis, alveolar hemorrhage, or unclassifiable pulmonary fibrosis, often present as part of syndromes that include hepatic, hematological, or skin disorders., Summary: This review explores the main genetic conditions identified over the past two decades., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Idiopathic pulmonary fibrosis (IPF) represents a severe and progressive manifestation of idiopathic interstitial pneumonia marked by an uncertain etiology along with an unfavorable prognosis. Osteoglycin (OGN), belonging to the small leucine-rich proteoglycans family, assumes pivotal functions in both tissue formation and damage response. However, the roles and potential mechanisms of OGN in the context of lung fibrosis remain unexplored., Methods: The assessment of OGN expression levels in fibrotic lungs was conducted across various experimental lung fibrosis mouse models. To elucidate the effects of OGN on the differentiation of lung myofibroblasts, both OGN knockdown and OGN overexpression were employed in vitro. The expression of integrin αv, along with its colocalization with lysosomes and latency-associated peptide (LAP), was monitored in OGN-knockdown lung myofibroblasts. Furthermore, the role of OGN in lung fibrosis was investigated through OGN knockdown utilizing adeno-related virus serotype 6 (AAV6)-mediated delivery., Results: OGN exhibited upregulation in both lungs and myofibroblasts across diverse lung fibrosis mouse models. And laboratory experiments in vitro demonstrated that OGN knockdown inhibited the TGF-β/Smad signaling pathway in lung myofibroblasts. Conversely, OGN overexpression promoted TGF-β/Smad pathway in these cells. Mechanistic insights revealed that OGN knockdown facilitated lysosome-mediated degradation of integrin αv while inhibiting its binding to latency-associated peptide (LAP). Remarkably, AAV6-targeted OGN knockdown ameliorated the extent of lung fibrosis in experimental mouse models., Conclusion: Our results indicate that inhibiting OGN signaling could serve as a promising therapeutic way for lung fibrosis., Competing Interests: Declaration of competing interest No conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Aging, a complex and profound journey, leads us through a labyrinth of physiological and pathological transformations, rendering us increasingly susceptible to aging-related diseases. Emerging investigations have unveiled the function of bromodomain containing protein 4 (BRD4) in manipulating the aging process and driving the emergence and progression of aging-related diseases., Aim of Review: This review aims to offer a comprehensive outline of BRD4's functions involved in the aging process, and potential mechanisms through which BRD4 governs the initiation and progression of various aging-related diseases., Key Scientific Concepts of Review: BRD4 has a fundamental role in regulating the cell cycle, apoptosis, cellular senescence, the senescence-associated secretory phenotype (SASP), senolysis, autophagy, and mitochondrial function, which are involved in the aging process. Several studies have indicated that BRD4 governs the initiation and progression of various aging-related diseases, including Alzheimer's disease, ischemic cerebrovascular diseases, hypertension, atherosclerosis, heart failure, aging-related pulmonary fibrosis, and intervertebral disc degeneration (IVDD). Thus, the evidence from this review supports that BRD4 could be a promising target for managing various aging-related diseases, while further investigation is warranted to gain a thorough understanding of BRD4's role in these diseases., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Production and hosting by Elsevier B.V.)

Pulmonary fibrosis (PF) is a clinically severe and commonly fatal complication of Systemic Sclerosis (SSc). Our group has previously reported profibrotic roles for Insulin-like Growth Factor II (IGF-II) and Lysyl Oxidase (LOX) in SSc-PF. We sought to identify downstream regulatory mediators of IGF-II. In the present work, we show that SSc lung tissues have higher baseline levels of the total (N-glycosylated/unglycosylated) LOX-Propeptide (LOX-PP) than control lung tissues. LOX-PP-mediated changes were consistent with the extracellular matrix (ECM) deregulation implicated in SSc-PF progression. Furthermore, Tolloid-like 1 (TLL1) and Bone Morphogenetic Protein 1 (BMP1), enzymes that can cleave ProLOX to release LOX-PP, were increased in SSc lung fibrosis and the bleomycin (BLM)-induced murine lung fibrosis model, respectively. In addition, IGF-II regulated the levels of ProLOX, active LOX, LOX-PP, BMP1, and isoforms of TLL1. The Class E Basic Helix-Loop-Helix protein 40 (BHLHE40) transcription factor localized to the nucleus in response to IGF-II. BHLHE40 silencing downregulated TLL1 isoforms and LOX-PP, and restored features of ECM deregulation triggered by IGF-II. Our findings indicate that IGF-II, BHLHE40, and LOX-PP may serve as targets of therapeutic intervention to halt SSc-PF progression., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The system of nitric oxide synthases (NOSs) is comprised of three isoforms: nNOS, iNOS, and eNOS. The roles of NOSs in respiratory diseases in vivo have been studied by using inhibitors of NOSs and NOS-knockout mice. Their exact roles remain uncertain, however, because of the non-specificity of inhibitors of NOSs and compensatory up-regulation of other NOSs in NOS-KO mice. We addressed this point in our triple-n/i/eNOSs-KO mice. Triple-n/i/eNOSs-KO mice spontaneously developed pulmonary emphysema and displayed exacerbation of bleomycin-induced pulmonary fibrosis as compared with wild-type (WT) mice. Triple-n/i/eNOSs-KO mice exhibited worsening of hypoxic pulmonary hypertension (PH), which was reversed by treatment with sodium nitrate, and WT mice that underwent triple-n/i/eNOSs-KO bone marrow transplantation (BMT) also showed aggravation of hypoxic PH compared with those that underwent WT BMT. Conversely, ovalbumin-evoked asthma was milder in triple-n/i/eNOSs-KO than WT mice. These results suggest that the roles of NOSs are different in different pathologic states, even in the same respiratory diseases, indicating the diversity of the roles of NOSs. In this review, we describe these previous studies and discuss the roles of NOSs in respiratory health and disease. We also explain the current state of development of inorganic nitrate as a new drug for respiratory diseases.

Idiopathic pulmonary fibrosis remains a relevant problem of the healthcare system with an unfavorable prognosis for patients due to progressive fibrous remodeling of the pulmonary parenchyma. Starting with the damage of the epithelial lining of alveoli, pulmonary fibrosis is implemented through a cascade of complex mechanisms, the crucial of which is the TGF-β/SMAD-mediated pathway, involving various cell populations. Considering that a number of the available drugs (pirfenidone and nintedanib) have only limited effectiveness in slowing the progression of fibrosis, the search and justification of new approaches aimed at regulating the immune response, cellular aging processes, programmed cell death, and transdifferentiation of cell populations remains relevant. This literature review presents the key modern concepts concerning molecular genetics and cellular mechanisms of lung fibrosis development, based mainly on in vitro and in vivo studies in experimental models of bleomycin-induced pulmonary fibrosis, as well as the latest data on metabolic features, potential targets, and effects of vitamin D and its metabolites.

Recent genetic and genomic advancements have elucidated the complex etiology of idiopathic pulmonary fibrosis (IPF) and other progressive fibrotic interstitial lung diseases (ILDs), emphasizing the contribution of heritable factors. This state-of-the-art review synthesizes evidence on significant genetic contributors to pulmonary fibrosis (PF), including rare genetic variants and common SNPs. The MUC5B promoter variant is unusual, a common SNP that markedly elevates the risk of early and established PF. We address the utility of genetic variation in enhancing understanding of disease pathogenesis and clinical phenotypes, improving disease definitions, and informing prognosis and treatment response. Critical research gaps are highlighted, particularly the underrepresentation of non-European ancestries in PF genetic studies and the exploration of PF phenotypes beyond usual interstitial pneumonia/IPF. We discuss the role of telomere length, often critically short in PF, and its link to progression and mortality, underscoring the genetic complexity involving telomere biology genes ( TERT , TERC ) and others like SFTPC and MUC5B . In addition, we address the potential of gene-by-environment interactions to modulate disease manifestation, advocating for precision medicine in PF. Insights from gene expression profiling studies and multiomic analyses highlight the promise for understanding disease pathogenesis and offer new approaches to clinical care, therapeutic drug development, and biomarker discovery. Finally, we discuss the ethical, legal, and social implications of genomic research and therapies in PF, stressing the need for sound practices and informed clinical genetic discussions. Looking forward, we advocate for comprehensive genetic testing panels and polygenic risk scores to improve the management of PF and related ILDs across diverse populations.

This study aims to investigate the mechanism of Xueshuantong Injection(XST) on pulmonary fibrosis induced by bleomycin(BLM) in rats based on the coagulation cascade pathway. Sixty SD rats were randomly divided into sham surgery group,model group, pirfenidone(PFD, 50 mg·kg~(-1)) group, and 27, 54, and 81 mg·kg~(-1) XST groups. The rat model of pulmonary fibrosis was established by intratracheal injection of BLM(5 mg·kg~(-1)). After 24 hours, the administration groups were given corresponding drugs, while the sham surgery group and model group were given equal volumes of saline. On the 28th day, samples were collected,and the imaging and collagen fiber changes in the lungs of rats were observed. Immunofluorescence(IF) method was used to detect the expression level of alpha-smooth muscle actin(α-SMA), collagen Ⅰ(Col-Ⅰ), E-cadherin(E-cad), and vimentin(Vim). Western blot was used to determine the protein expression of α-SMA, Col-Ⅰ, Vim, and E-cad. Enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of prothrombin fragment(F1 + 2), thrombin-antithrombin complex(TAT), soluble fibrin monomer complex(SFMC), and rat fibrinogen degradation products(FDP) in rat lung tissue. Finally, the mRNA and protein levels of protease activated receptor 1(PAR-1) were detected by RT-qPCR, western blot, and IF. Compared with the model group, the scanning of the lungs of rats receiving XST treatment also exhibited patchy and non-homogeneous shadows, but these shadows were less dense than those in the model group. At the same time, there was a significant decrease in Col-Ⅰ fibers in the lungs of rats, and XST could inhibit epithelial-mesenchymal transition(EMT) and downregulate α-SMA and Col-Ⅰ protein expression. In the aspect of the coagulation system, administration of 81 mg·kg~(-1) XST significantly reduced the levels of SFMC and FDP. Meanwhile, 81 mg·kg~(-1) XST significantly downregulated the mRNA and protein levels of PAR-1. XST has an anti-pulmonary fibrosis effect in rats, and its mechanism may be related to the downregulation of PAR-1 to rebalance the coagulation cascade pathway.

The mechanism of alleviating bleomycin-induced pulmonary fibrosis in mice was compared between Qingqiao(Forsythiae Fructus produced with immature fruits) and Laoqiao(Forsythiae Fructus produced with mature fruits) from the pharmacodynamic correlation and composition differences. Mice were randomized into normal, model, pirfenidone(50 mg·kg~(-1)), low-and high-dose(1.3, 2.6 g·kg~(-1), respectively) Qingqiao, and low-and high-dose(1.3, 2.6 g·kg~(-1), respectively) Laoqiao groups. The mouse model of pulmonary fibrosis was established by intratracheal instillation of bleomycin, during which the survival rate and body weight changes of the mice were measured. After modeling, the lung index was calculated, and the pathological changes in the lung tissue were evaluated by hematoxylin-eosin(HE), Masson, and Sirius red staining. Transmission electron microscopy was employed to observe the ultrastructure of the lung tissue. The biochemical assay was employed to measure the levels of transforming growth factor-β1(TGF-β1), α-smooth muscle actin(α-SMA), E-cadherin, and hydroxyproline(HYP) in the lung tissue and interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) in the bronchoalveolar lavage fluid(BALF). The mRNA and protein levels of matrix metalloproteinase 7(MMP7), collagen Ⅰ, E-cadherin, TNF-α, vimentin, TGF-β1, and α-SMA in the lung tissue were determined by RT-qPCR and Western blot, respectively. The expression of α-SMA in the lung tissue was detected by the immunofluorescence assay. Principal component analysis was performed to compare the effects of Qingqiao and Laoqiao in ameliorating pulmonary fibrosis. Molecular docking was employed to analyze the binding between the compounds with high content in Laoqiao and TGF-β1. The cell-counting kit(CCK-8) assay was used to examine the effects of the active compounds on TGF-β1-induced BEAS-2B and HFL1 cell models. The results showed that Qingqiao and Laoqiao increased the survival rate, reduced the lung index, alleviated the pathological damage and collagen deposition in the lung tissue, ameliorated the damage of lamellar bodies in alveolar epithelial type Ⅱ cells, lowered the level of IL-6 and TNF-α in the BALF, down-regulated the expression of HYP, MMP7, vimentin, collagen Ⅰ, TGF-β1, and α-SMA, and up-regulated the expression of E-cadherin in the lung tissue of the mouse model of pulmonary fibrosis. The collagen deposition in the mouse model of pulmonary fibrosis was comprehensively evaluated by principal component analysis, and the effects of different treatments followed the trend of high-dose Laoqiao&gt;low-dose Laoqiao&gt;high-dose Qingqiao&gt;low-dose Qingqiao. Molecular docking showed that hydroxytyrosol, caffeic acid, phillygenin, and(-)-lariciresinol had strong binding affinity with TGF-β1 receptor. The results of cell experiments showed that these compounds significantly attenuated the TGF-β1-induced damage in BEAS-2B cells and inhibited the TGF-β1-induced proliferation of HFL1 cells. In conclusion, both Qingqiao and Laoqiao were effective in ameliorating bleomycin-induced pulmonary fibrosis in mice. Laoqiao was superior to Qingqiao in reducing collagen deposition, which might be attributed to the higher content of hydroxytyrosol, caffeic acid, phillygenin, and(-)-lariciresinol in Laoqiao than in Qingqiao.

Telomere biology disorder (TBD) can present within a wide spectrum of symptoms ranging from severe congenital malformations to isolated organ dysfunction in adulthood. Diagnosing TBD can be challenging given the substantial variation in symptoms and age of onset across generations. In this report, we present two families, one with a pathogenic variant in ZCCHC8 and another with a novel variant in TERC. In the literature, only one family has previously been reported with a ZCCHC8 variant and TBD symptoms. This family had multiple occurrences of pulmonary fibrosis and one case of bone marrow failure. In this paper, we present a second family with the same ZCCHC8 variant (p.Pro186Leu) and symptoms of TBD including pulmonary fibrosis, hematological disease, and elevated liver enzymes. The suspicion of TBD was confirmed with the measurement of short telomeres in the proband. In another family, we report a novel likely pathogenic variant in TERC. Our comprehensive description encompasses hematological manifestations, as well as pulmonary and hepatic fibrosis. Notably, there are no other reports which associate this variant to disease. The families expand our understanding of the clinical implications and genetic causes of TBD., (© 2024 The Authors. Clinical Genetics published by John Wiley & Sons Ltd.)

Combined pulmonary fibrosis and emphysema (CPFE) presents a unique challenge in respiratory disorders, merging features of interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD). Using the random forest algorithm, our study thoroughly examines the molecular details of CPFE. Analyzing gene expression datasets from GSE47460 (ILD: 254, COPD: 220, control: 108), we identify key genes namely ADRB2, CDH3, IRS2, MATN3, CD38, PDIA4, VEGFC, and among twenty others, crucial in airway regulation, lung function, and apoptosis, shaping the complex pathogenesis of CPFE. Additionally, miRNAs (hsa-mir-101-3p, hsa-mir-1343-3p, hsa-mir-27a-3p, and miR-16-5p) showcase regulatory impacts on CPFE-related molecular pathways. Our machine learning model unveils these intricate interactions, offering a comprehensive insight into CPFE's molecular mechanisms. This research not only pinpoints potential therapeutic targets and biomarkers but also opens avenues for innovative approaches in managing CPFE, linking ILD and COPD within this complex respiratory condition., (© 2024. International Federation for Medical and Biological Engineering.)

Idiopathic pulmonary fibrosis, a fatal interstitial lung disease, is characterized by fibroblast activation and aberrant extracellular matrix accumulation. Effective therapeutic development is limited because of incomplete understanding of the mechanisms by which fibroblasts become aberrantly activated. Here, we show aldehyde dehydrogenase 2 (ALDH2) in fibroblasts as a potential therapeutic target for pulmonary fibrosis. A decrease in ALDH2 expression was observed in patients with idiopathic pulmonary fibrosis and bleomycin-treated mice. ALDH2 deficiency spontaneously induces collagen accumulation in the lungs of aged mice. Furthermore, young ALDH2 knockout mice exhibited exacerbated bleomycin-induced pulmonary fibrosis and increased mortality compared with that in control mice. Mechanistic studies revealed that transforming growth factor (TGF)-β1 induction and ALDH2 depletion constituted a positive feedback loop that exacerbates fibroblast activation. TGF-β1 down-regulated ALDH2 through a TGF-β receptor 1/Smad3-dependent mechanism. The subsequent deficiency in ALDH2 resulted in fibroblast dysfunction that manifested as impaired mitochondrial autophagy and senescence, leading to fibroblast activation and extracellular matrix production. ALDH2 overexpression markedly suppressed fibroblast activation, and this effect was abrogated by PTEN-induced putative kinase 1 (PINK1) knockdown, indicating that the profibrotic effects of ALDH2 are PINK1- dependent. Furthermore, ALDH2 activated by N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide (Alda-1) reversed the established pulmonary fibrosis in both young and aged mice. In conclusion, ALDH2 expression inhibited the pathogenesis of pulmonary fibrosis. Strategies to up-regulate or activate ALDH2 expression could be potential therapies for pulmonary fibrosis., Competing Interests: Dislcosure Statement None declared., (Copyright © 2024 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Exposure to acrylic amide (AD) has garnered worldwide attention due to its potential adverse health effects, prompting calls from the World Health Organization for intensified research into associated risks. Despite this, the relationship between oral acrylic amide (acrylamide) (AD) exposure and pulmonary dysfunction remains poorly understood. Our study aimed to investigate the correlation between internal oral exposure to AD and the decline in lung function, while exploring potential mediating factors such as tissue inflammation, oxidative stress, pyroptosis, and apoptosis. Additionally, we aimed to evaluate the potential protective effect of zinc oxide nanoparticles green-synthesized moringa extract (ZNO-MONPs) (10 mg/kg b.wt) against ACR toxicity and conducted comprehensive miRNA expression profiling to uncover novel targets and mechanisms of AD toxicity (miRNA 223-3 P and miRNA 325-3 P). Furthermore, we employed computational techniques to predict the interactions between acrylic amide and/or MO-extract components and tissue proteins. Using a rat model, we exposed animals to oral acrylamide (20 mg/kg b.wt for 2 months). Our findings revealed that AD significantly downregulated the expression of miRNA 223-3 P and miRNA 325-3 P, targeting NLRP-3 & GSDMD, respectively, indicating the induction of pyroptosis in pulmonary tissue via an inflammasome activating pathway. Moreover, AD exposure resulted in lipid peroxidative damage and reduced levels of GPX, CAT, GSH, and GSSG. Notably, AD exposure upregulated apoptotic, pyroptotic, and inflammatory genes, accompanied by histopathological damage in lung tissue. Immunohistochemical and immunofluorescence techniques detected elevated levels of indicative harmful proteins including vimentin and 4HNE. Conversely, concurrent administration of ZNO-MONPs with AD significantly elevated the expression of miRNA 223-3 P and miRNA 325-3 P, protecting against oxidative stress, apoptosis, pyroptosis, inflammation, and fibrosis in rat lungs. In conclusion, our study highlights the efficacy of ZNO-MONPs NPs in protecting pulmonary tissue against the detrimental impacts of foodborne toxin AD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The ATP-binding cassette subfamily A member 3 (ABCA3) protein plays a fundamental role in surfactant homeostasis. Most children with ABCA3 gene mutations develop pulmonary interstitial fibrosis leading to the development of interstitial lung disease. Since traditional medicine does not offer effective therapy, the best option is lung transplantations, especially bilateral lung transplantations. We are reporting the case of a successful bilateral lung transplantation in a five-year-old child with pulmonary interstitial fibrosis caused by ABCA3 gene mutations. This successful transplantation enabled the patient to get rid of chronic cough and tachypnea., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Severe COVID-19 infection has been associated with the development of pulmonary fibrosis, a condition that significantly affects patient prognosis. Understanding the underlying cellular communication mechanisms contributing to this fibrotic process is crucial., Objective: In this study, we aimed to investigate the role of the TNFSF12-TNFRSF12A pathway in mediating communication between alveolar macrophages and fibroblasts, and its implications for the development of pulmonary fibrosis in severe COVID-19 patients., Methods: We conducted single-cell RNA sequencing (scRNA-seq) analysis using lung tissue samples from severe COVID-19 patients and healthy controls. The data was processed, analyzed, and cell types were annotated. We focused on the communication between alveolar macrophages and fibroblasts and identified key signaling pathways. In vitro experiments were performed to validate our findings, including the impact of TNFRSF12A silencing on fibrosis reversal., Results: Our analysis revealed that in severe COVID-19 patients, alveolar macrophages communicate with fibroblasts primarily through the TNFSF12-TNFRSF12A pathway. This communication pathway promotes fibroblast proliferation and expression of fibrotic factors. Importantly, silencing TNFRSF12A effectively reversed the pro-proliferative and pro-fibrotic effects of alveolar macrophages., Conclusion: The TNFSF12-TNFRSF12A pathway plays a central role in alveolar macrophage-fibroblast communication and contributes to pulmonary fibrosis in severe COVID-19 patients. Silencing TNFRSF12A represents a potential therapeutic strategy for mitigating fibrosis in severe COVID-19 lung disease., (© 2024. The Author(s).)

Fibrosis in the lung is thought to be driven by epithelial cell dysfunction and aberrant cell-cell interactions. Unveiling the molecular mechanisms of cellular plasticity and cell-cell interactions is imperative to elucidating lung regenerative capacity and aberrant repair in pulmonary fibrosis. By mining publicly available RNA-Seq data sets, we identified loss of CCAAT enhancer-binding protein alpha (CEBPA) as a candidate contributor to idiopathic pulmonary fibrosis (IPF). We used conditional KO mice, scRNA-Seq, lung organoids, small-molecule inhibition, and potentially novel gene manipulation methods to investigate the role of CEBPA in lung fibrosis and repair. Long-term (6 months or more) of Cebpa loss in AT2 cells caused spontaneous fibrosis and increased susceptibility to bleomycin-induced fibrosis. Cebpa knockout (KO) in these mice significantly decreased AT2 cell numbers in the lung and reduced expression of surfactant homeostasis genes, while increasing inflammatory cell recruitment as well as upregulating S100a8/a9 in AT2 cells. In vivo treatment with an S100A8/A9 inhibitor alleviated experimental lung fibrosis. Restoring CEBPA expression in lung organoids ex vivo and during experimental lung fibrosis in vivo rescued CEBPA deficiency-mediated phenotypes. Our study establishes a direct mechanistic link between CEBPA repression, impaired AT2 cell identity, disrupted tissue homeostasis, and lung fibrosis.

Background: miRNAs are small, conserved, single-stranded non-coding RNA that are typically transported by exosomes for their functional roles. The therapeutic potential of exosomal miRNAs has been explored in various diseases including breast cancer, pancreatic cancer, cholangiocarcinoma, skin diseases, Alzheimer's disease, stroke, and glioma. Pathophysiological processes such as cellular inflammation, apoptosis, necrosis, immune dysfunction, and oxidative stress are closely associated with miRNAs. Internal and external factors such as tissue ischemia, hypoxia, pathogen infection, and endotoxin exposure can trigger these reactions and are linked to miRNAs. Paraquat-induced fibrosis is a protracted process that may not manifest immediately after injury but develops during bodily recovery, providing insights into potential miRNA intervention treatments., Rationale: These findings could potentially be applied for further pharmaceutical research and clinical therapy of paraquat-induced pulmonary fibrosis, and are likely to be of great interest to clinicians involved in lung fibrosis research., Methodology: Through a literature review, we identified an association between miR-15a-5p and miR-152-3p and their involvement in the Wnt signaling pathway. This allowed us to deduce the molecular mechanisms underlying regulatory interactions involved in paraquat-induced lung fibrosis., Results: miR-15a-5p and miR-152-3p play roles in body repair processes, and pulmonary fibrosis can be considered a form of reparative response by the body. Although the initial purpose of fibrotic repair is to restore normal body function, excessive tissue fibrosis, unlike scar formation following external skin trauma, can significantly and adversely affect the body. Modulating the Wnt/β-catenin signaling pathway is beneficial in alleviating tissue fibrosis in various diseases., Conclusions: In this study, we delineate the association between miR-15a-5p and miR-152-3p and the Wnt/β-catenin signaling pathway, presenting a novel concept for addressing paraquat-induced pulmonary fibrosis., Competing Interests: The authors declare that they have no competing interests., (© 2024 Liu and Guan.)

Background: Pulmonary fibrosis (PF) is a group of respiratory diseases that are extremely complex and challenging to treat. Due to its high mortality rate and short survival, it's often referred to as a "tumor-like disease" that poses a serious threat to human health., Objective: We aimed validate the potential of Deapioplatycodin D (DPD) to against PF and clarify the underlying mechanism of action of DPD for the treatment of PF based on bioinformatics and experimental verification. This finding provides a basis for the development of safe and effective therapeutic PF drugs based on DPD., Methods: We used LPS-induced early PF rats as a PF model to test the overall efficacy of DPD in vivo. Then, A variety of bioinformatics methods, such as WGCNA, LASSO algorithm and immune cell infiltration (ICI), were applied to analyze the gene microarray related to PF obtained from Gene Expression Omnibus (GEO) to obtained key targets of PF. Finally, an in vitro PF model was constructed based on BEAS-2B cells while incorporating rat lung tissues to validate the regulatory effects of DPD on critical genes., Results: DPD can effectively alleviate inflammatory and fibrotic markers in rat lungs. WGCNA analysis resulted in a total of six expression modules, with the brown module having the highest correlation with PF. Subsequently, seven genes were acquired by intersecting the genes in the brown module with DEGs. Five key genes were identified as potential biomarkers of PF by LASSO algorithm and validation dataset verification analysis. In the ICI analysis, infiltration of activated B cell, immature B cell and natural killer cells were found to be more crucial in PF. Ultimately, it was observed that DPD could modulate key genes to achieve anti-PF effects., Conclusion: In short, these comprehensive analysis methods were employed to identify critical biomarkers closely related to PF, which helps to elucidate the pathogenesis and potential immunotherapy targets of PF. It also provides essential support for the potential of DPD against PF., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aims: Pulmonary fibrosis (PF) is a progressive and incurable lung disease for which treatment options are limited. Here, we aimed to conduct an exploratory study on the effects of the Mongolian medicine Saorilao-4 (SRL) on the gut microbiota structure, species abundance, and diversity of a rat PF model as well as the mechanisms underlying such effects., Methods and Results: Rat fecal samples were analyzed using 16S rRNA sequencing technology. Bioinformatic and correlation analyses were performed on microbiota data to determine significant associations. SRL substantially attenuated the adverse effects exerted by PF on the structure and diversity of gut microbiota while regulating its alpha and beta diversities. Linear discriminant analysis effect size enabled the identification of 62 differentially abundant microbial taxa. Gut microbiota abundance analysis revealed that SRL significantly increased the relative abundance of bacterial phyla such as Firmicutes and Bacteroidetes. Moreover, SRL increased the proportion of beneficial bacteria, such as Lactobacillus and Bifidobacteriales, decreased the proportion of pathogenic bacteria, such as Rikenellaceae, and balanced the gut microbiota by regulating metabolic pathways., Conclusions: SRL may attenuate PF by regulating gut microbiota. This exploratory study establishes the groundwork for investigating the metagenomics of PF., (© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.)

Pulmonary fibrosis is characterized by pathological accumulation of scar tissue in the lung parenchyma. Many of the processes that are implicated in fibrosis, including increased extracellular matrix synthesis, also occur following pneumonectomy (PNX), but PNX instead results in regenerative compensatory growth of the lung. As fibroblasts are the major cell type responsible for extracellular matrix production, we hypothesized that comparing fibroblast responses to PNX and bleomycin (BLM) would unveil key differences in the role they play during regenerative versus fibrotic lung responses. RNA-sequencing was performed on flow-sorted fibroblasts freshly isolated from mouse lungs 14 days after BLM, PNX, or sham controls. RNA-sequencing analysis revealed highly similar biological processes to be involved in fibroblast responses to both BLM and PNX, including TGF-β1 and TNF-α. Interestingly, we observed smaller changes in gene expression after PNX than BLM at Day 14, suggesting that the fibroblast response to PNX may be muted by expression of transcripts that moderate pro-fibrotic pathways. Itpkc, encoding inositol triphosphate kinase C, was a gene uniquely up-regulated by PNX and not BLM. ITPKC overexpression in lung fibroblasts antagonized the pro-fibrotic effect of TGF-β1. RNA-sequencing analysis has identified considerable overlap in transcriptional changes between fibroblasts following PNX and those overexpressing ITPKC., (© 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Progressive lung fibrosis is associated with poorly understood aging-related endothelial cell dysfunction. To gain insight into endothelial cell alterations in lung fibrosis we performed single cell RNA-sequencing of bleomycin-injured lungs from young and aged mice. Analysis reveals activated cell states enriched for hypoxia, glycolysis and YAP/TAZ activity in ACKR1+ venous and TrkB+ capillary endothelial cells. Endothelial cell activation is prevalent in lungs of aged mice and can also be detected in human fibrotic lungs. Longitudinal single cell RNA-sequencing combined with lineage tracing demonstrate that endothelial activation resolves in young mouse lungs but persists in aged ones, indicating a failure of the aged vasculature to return to quiescence. Genes associated with activated lung endothelial cells states in vivo can be induced in vitro by activating YAP/TAZ. YAP/TAZ also cooperate with BDNF, a TrkB ligand that is reduced in fibrotic lungs, to promote capillary morphogenesis. These findings offer insights into aging-related lung endothelial cell dysfunction that may contribute to defective lung injury repair and persistent fibrosis., (© 2024. The Author(s).)