Dexmedetomidine alleviates pulmonary fibrosis through the ADORA2B-Mediated MAPK signaling pathway.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronically progressive fibrotic pulmonary disease characterized by an uncertain etiology, a poor prognosis, and a paucity of efficacious treatment options. Dexmedetomidine (Dex), an anesthetic-sparing alpha-2 adrenoceptor (α2AR) agonist, plays a crucial role in organ injury and fibrosis. However, the underlying mechanisms of IPF remain unknown. METHODS: In our study, the role of Dex in murine pulmonary fibrosis models was determined by Dex injection intraperitoneally in vivo. Fibroblast activation and myofibroblast differentiation were assessed after Dex treatment in vitro. The activation of MAPK pathway and the expression of Adenosine A2B receptor (ADORA2B) were examined in lung myofibroblasts. Moreover, the role of ADORA2B in Dex suppressing myofibroblast differentiation and pulmonary fibrosis was determined using the ADORA2B agonist BAY60-6583. RESULTS: The results revealed that Dex could inhibit Bleo-induced pulmonary fibrosis in mice. In vitro studies revealed that Dex suppressed TGF-ß-mediated MAPK pathway activation and myofibroblast differentiation. Furthermore, Dex inhibits myofibroblast differentiation and pulmonary fibrosis via downregulating ADORA2B expression. CONCLUSIONS: Our findings suggest Dex as a potential therapeutic agent for pulmonary fibrosis. Dex may alleviate lung fibrosis and myofibroblast differentiation through the ADORA2B-mediated MAPK signaling pathway.

Asporin Promotes TGF-ß-induced Lung Myofibroblast Differentiation by Facilitating Rab11-Dependent Recycling of TßRI.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disease with high mortality and morbidity. ASPN (asporin), a member of the small leucine-rich proteoglycan family, plays crucial roles in tissue injury and regeneration. However, the precise pathophysiological role of ASPN and its molecular mechanisms in IPF remain unknown. We sought to investigate the role of ASPN during the development of pulmonary fibrosis and the therapeutic potential of targeting ASPN-related signaling pathways. In our study, three microarray datasets were downloaded from the Gene Expression Omnibus database, and differentially expressed genes were screened out by bioinformatic analysis. Hub genes were selected from the protein-protein interaction network. ASPN was examined in lung tissues from pulmonary fibrosis mouse models, and the role of ASPN in transforming growth factor (TGF)-ß/Smad signaling was determined by transfection with ASPN shRNA vectors in vitro. Biotinylation assays were conducted to measure plasma membrane TFG-ß receptor I (TßRI) and TßRI recycling after ASPN knockdown. The results showed ASPN expression was increased in the lungs of pulmonary fibrosis mouse models, and ASPN was primarily localized in α-SMA+ myofibroblasts. In vitro experiments proved that ASPN knockdown inhibited TGF-ß/Smad signaling and myofibroblast differentiation by regulating the stability of TßRI. Further molecular mechanisms revealed that ASPN knockdown inhibited TGF-ß/Smad signaling by suppressing recycling of TßRI to the cell surface in a Rab11-dependent manner and facilitated lysosome-mediated degradation of TßRI. In conclusion, our findings provide important evidence for the use of ASPN as a novel pharmacological target for treating pulmonary fibrosis.

Identification of diagnostic hub genes related to neutrophils and infiltrating immune cell alterations in idiopathic pulmonary fibrosis.

Background: There is still a lack of specific indicators to diagnose idiopathic pulmonary fibrosis (IPF). And the role of immune responses in IPF is elusive. In this study, we aimed to identify hub genes for diagnosing IPF and to explore the immune microenvironment in IPF. Methods: We identified differentially expressed genes (DEGs) between IPF and control lung samples using the GEO database. Combining LASSO regression and SVM-RFE machine learning algorithms, we identified hub genes. Their differential expression were further validated in bleomycin-induced pulmonary fibrosis model mice and a meta-GEO cohort consisting of five merged GEO datasets. Then, we used the hub genes to construct a diagnostic model. All GEO datasets met the inclusion criteria, and verification methods, including ROC curve analysis, calibration curve (CC) analysis, decision curve analysis (DCA) and clinical impact curve (CIC) analysis, were performed to validate the reliability of the model. Through the Cell Type Identification by Estimating Relative Subsets of RNA Transcripts algorithm (CIBERSORT), we analyzed the correlations between infiltrating immune cells and hub genes and the changes in diverse infiltrating immune cells in IPF. Results: A total of 412 DEGs were identified between IPF and healthy control samples, of which 283 were upregulated and 129 were downregulated. Through machine learning, three hub genes (ASPN, SFRP2, SLCO4A1) were screened. We confirmed their differential expression using pulmonary fibrosis model mice evaluated by qPCR, western blotting and immunofluorescence staining and analysis of the meta-GEO cohort. There was a strong correlation between the expression of the three hub genes and neutrophils. Then, we constructed a diagnostic model for diagnosing IPF. The areas under the curve were 1.000 and 0.962 for the training and validation cohorts, respectively. The analysis of other external validation cohorts, as well as the CC analysis, DCA, and CIC analysis, also demonstrated strong agreement. There was also a significant correlation between IPF and infiltrating immune cells. The frequencies of most infiltrating immune cells involved in activating adaptive immune responses were increased in IPF, and a majority of innate immune cells showed reduced frequencies. Conclusion: Our study demonstrated that three hub genes (ASPN, SFRP2, SLCO4A1) were associated with neutrophils, and the model constructed with these genes showed good diagnostic value in IPF. There was a significant correlation between IPF and infiltrating immune cells, indicating the potential role of immune regulation in the pathological process of IPF.

DACT2 protects against pulmonary fibrosis via suppressing glycolysis in lung myofibroblasts.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disease with poor prognosis and few treatment options. Dapper homolog 2 (DACT2), a member of the DACT gene family, plays crucial roles in tissue development and injury. However, its functions and molecular mechanisms in IPF remain largely unknown. We aimed to investigate the role of DACT2 in the development of pulmonary fibrosis and the therapeutic potential of targeting DACT2 related signaling pathways. METHODS: In our study, adeno-associated virus serotype 6 (AAV6)-mediated DACT2 overexpression was assessed in several mice models of experimental pulmonary fibrosis in vivo. The role of DACT2 in lung myofibroblast differentiation was determined by DACT2 overexpression in vitro. The glucose uptake, extracellular acidification rate, intracellular adenosine-triphosphate (ATP) level and lactate levels of myofibroblasts were detected after DACT2 overexpression. The LDHA degradation rate and colocalization with lysosomes were monitored as well. RESULTS: Intratracheal administration of AAV6-mediated DACT2 overexpression apparently attenuated pulmonary fibrosis in experimental pulmonary fibrosis models. In vitro experiments revealed that DACT2 inhibited TGF-ß-induced myofibroblast differentiation by promoting lysosome-mediated LDHA degradation and thus suppressing glycolysis in myofibroblasts. CONCLUSION: In conclusion, our findings support for DACT2 as a novel pharmacological target for pulmonary fibrosis treatments.

Mesenchymal stromal cells attenuate alveolar type 2 cells senescence through regulating NAMPT-mediated NAD metabolism.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive deadly fibrotic lung disease with high prevalence and mortality worldwide. The therapeutic potential of mesenchymal stem cells (MSCs) in pulmonary fibrosis may be attributed to the strong paracrine, anti-inflammatory, anti-apoptosis and immunoregulatory effects. However, the mechanisms underlying the therapeutic effects of MSCs in IPF, especially in terms of alveolar type 2 (AT2) cells senescence, are not well understood. The purpose of this study was to evaluate the role of MSCs in NAD metabolism and senescence of AT2 cells in vitro and in vivo. METHODS: MSCs were isolated from human bone marrow. The protective effects of MSCs injection in pulmonary fibrosis were assessed via bleomycin mouse models. The senescence of AT2 cells co-cultured with MSCs was evaluated by SA-ß-galactosidase assay, immunofluorescence staining and Western blotting. NAD+ level and NAMPT expression in AT2 cells affected by MSCs were determined in vitro and in vivo. FK866 and NAMPT shRNA vectors were used to determine the role of NAMPT in MSCs inhibiting AT2 cells senescence. RESULTS: We proved that MSCs attenuate bleomycin-induced pulmonary fibrosis in mice. Senescence of AT2 cells was alleviated in MSCs-treated pulmonary fibrosis mice and when co-cultured with MSCs in vitro. Mechanistic studies showed that NAD+ and NAMPT levels were rescued in AT2 cells co-cultured with MSCs and MSCs could suppress AT2 cells senescence mainly via suppressing lysosome-mediated NAMPT degradation. CONCLUSIONS: MSCs attenuate AT2 cells senescence by upregulating NAMPT expression and NAD+ levels, thus exerting protective effects in pulmonary fibrosis.