Transcriptomic study on the effect of Igf1r deficiency in control and bleomycin-challenged mouse lungs.
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ABSTRACT: Acute lung injury (ALI), ARDS and COVID-19 usually involve a “cytokine storm”. IGF1R (Insulin-like growth factor receptor 1) maintains lung homeostasis and is implicated in these pulmonary inflammatory diseases. In mice, widespread IGF1R deficiency was reported to counteract respiratory inflammation and alveolar damage after bleomycin (BLM)-induced ALI. To explore the molecular mechanisms mediated by Igf1r signaling after BLM challenge, we performed RNA-sequencing in lungs of IGF1R-deficient mice after BLM or saline (SAL) instillation. Transcriptomic analysis identified differentially expressed genes between BLM-challenged and SAL-treated control lungs, detecting biological processes and signaling pathways involved in ALI pathobiology. Igf1r depletion in BLM-challenged mice reversed large part of the transcriptional changes triggered by BLM, counteracting the transcriptomic profile of the inflammatory "cytokine storm". Data mining also identified changes in the expression of gene clusters with key roles in DNA damage, metabolic reprogramming, mitochondrial homeostasis, and epigenetics. Exploration of these functional groups, together with validation studies, provide new insights into the molecular mechanisms underlying the attenuating effect of Igf1r deficiency on ALI. These findings allow a more comprehensive view of IGF1R signaling at the transcriptional level, reinforcing its important role in promoting ALI and postulating it as a global epigenetic regulator in ARDS.
Project description:Background: Acute Respiratory Distress Syndrome (ARDS) or its earlier stage Acute lung injury (ALI), is a worldwide health concern that jeopardizes human well-being. Currently, the treatment strategies to mitigate the incidence and mortality of ARDS are severely restricted. This limitation can be attributed, at least in part, to the substantial variations in immunity observed in individuals with this syndrome. Methods: Bulk and single cell RNA sequencing from ALI mice and single cell RNA sequencing from ARDS patients were analyzed. We utilized the Seurat program package in R and cellmarker 2.0 to cluster and annotate the data. The differential, enrichment, protein interaction, and cell-cell communication analysis were conducted. Results: The mice with ALI caused by pulmonary and extrapulmonary factors demonstrated differential expression including Clec4e, Retnlg, S100a9, Coro1a, and Lars2. We have determined that inflammatory factors have a greater significance in extrapulmonary ALI, while multiple pathways collaborate in the development of pulmonary ALI. Clustering analysis revealed significant heterogeneity in the relative abundance of immune cells in different ALI models. The autocrine action of neutrophils plays a crucial role in pulmonary ALI. Additionally, there was a significant increase in signaling intensity between B cells and M1 macrophages, NKT cells and M1 macrophages in extrapulmonary ALI. The CXCL, CSF3 and MIF, TGFβ signaling pathways play a vital role in pulmonary and extrapulmonary ALI, respectively. Moreover, the analysis of human single-cell revealed DCs signaling to monocytes and neutrophils in COVID-19-related ARDS is stronger compared to sepsis-associated ARDS. In sepsis-associated ARDS, CD8+ T and Th cells exhibit more prominent signaling to B-cell nucleated DCs. Meanwhile, both MIF and CXCL signaling pathways are specific to sepsis-associated ARDS. Conclusions: This study has identified specific gene signatures and signaling pathways in animal models and human samples that facilitate the interaction between immune cells, which could be targeted therapeutically in ARDS patients of various etiologies.
Project description:Background: Acute Respiratory Distress Syndrome (ARDS) or its earlier stage Acute lung injury (ALI), is a worldwide health concern that jeopardizes human well-being. Currently, the treatment strategies to mitigate the incidence and mortality of ARDS are severely restricted. This limitation can be attributed, at least in part, to the substantial variations in immunity observed in individuals with this syndrome. Methods: Bulk and single cell RNA sequencing from ALI mice and single cell RNA sequencing from ARDS patients were analyzed. We utilized the Seurat program package in R and cellmarker 2.0 to cluster and annotate the data. The differential, enrichment, protein interaction, and cell-cell communication analysis were conducted. Results: The mice with ALI caused by pulmonary and extrapulmonary factors demonstrated differential expression including Clec4e, Retnlg, S100a9, Coro1a, and Lars2. We have determined that inflammatory factors have a greater significance in extrapulmonary ALI, while multiple pathways collaborate in the development of pulmonary ALI. Clustering analysis revealed significant heterogeneity in the relative abundance of immune cells in different ALI models. The autocrine action of neutrophils plays a crucial role in pulmonary ALI. Additionally, there was a significant increase in signaling intensity between B cells and M1 macrophages, NKT cells and M1 macrophages in extrapulmonary ALI. The CXCL, CSF3 and MIF, TGFb signaling pathways play a vital role in pulmonary and extrapulmonary ALI, respectively. Moreover, the analysis of human single-cell revealed DCs signaling to monocytes and neutrophils in COVID-19-associated ARDS is stronger compared to sepsis-related ARDS. In sepsis-related ARDS, CD8+ T and Th cells exhibit more prominent signaling to B cell nucleated DCs. Meanwhile, both MIF and CXCL signaling pathways are specific to sepsis-related ARDS. Conclusion: This study has identified specific gene signatures and signaling pathways in animal models and human samples that facilitate the interaction between immune cells, which could be targeted therapeutically in ARDS patients of various etiologies.
Project description:IGF1R (Insulin-like Growth Factor 1 Receptor) is a ubiquitously expressed transmembrane tyrosine kinase receptor with multiple functions including inflammation. IGF activity maintains human lung homeostasis, being involved in relevant pulmonary diseases with an inflammatory component, such as lung cancer, COPD, asthma and pulmonary fibrosis. Here we examined the role of IGF1R in lung inflammation using mice with a postnatal deficiency of Igf1r and a model of bleomycin(BLM)-induced lung injury. Lung transcriptome analysis of Igf1r-deficient mice showed a general inhibition of transcription of genes related to epigenetics, inflammation/immune response and oxidative stress activity with potential pulmonary protective roles. Early upon intratracheal BLM treatment, mutant mice showed improved survival and milder pulmonary injury and inflammation. Their lungs presented down-regulation of macrophage (Marco/Adgre1), neutrophil-related (Cxcl1/Ly6g), pro-inflammatory (Tnf/Il1b/Il6), endothelial adhesion (Icam1/Pecam1) and alveolar damage (Aqp5/Sftpc) markers and up-regulation of resolution phase markers (Csf1/Il13/Cd209a). Changes in mRNA of IGF system genes were also found, in parallel to a hindered response to hypoxia (Hif1a) and increased expression of the anti-oxidative stress marker Gpx8. These findings identify Igf1r as an important player in oxidative stress and inflammation and suggest that targeting Igf1r may block the inflammatory response in lung diseases with this component.
Project description:Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common life-threatening critical syndrome with no effective pharmacotherapy. Extracellular vesicles (EVs) are considered as a new way of long-distance communication between cells. Our previous research using an ex vivo perfused human ALI model suggested that endothelial cell-derived EVs (EC-EVs) mediate the development of ALI/ARDS. However, how EC-EVs aggravate lung injury remains largely unknown. Here we demonstrated that EC-EVs released under inflammatory stimulation are preferentially taken up by monocytes and reprogram the differentiation of monocytes towards M1 type macrophage. These findings demonstrate a previously unidentified mechanism by which distant infections could lead to ALI/ARDS, providing novel targets and strategies for the prevention and treatment of sepsis-related ALI/ARDS.
Project description:Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe conditions with high morbidity and mortality, and effective treatments are limited. Neuroimmune interactions play a critical role in lung homeostasis, but it remains unclear if specific brain regions regulate lung inflammation. Here, we unveil the critical role of neuroimmune signaling in ALI, focusing on the regulatory function of corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus (PVN) of the hypothalamus. Using viral tracing, chemogenetic modulation, and pharmacological interventions in mouse models of ALI induced by intranasal lipopolysaccharide and cecal ligation and puncture (CLP), we found that lung injury activated CRHPVN neurons that projected to the lung. Activation of these neurons protected mice from ALI and death, reducing neutrophil infiltration and effector functions in the lung. In contrast, inhibiting CRHPVN neurons exacerbated ALI. Notably, the beneficial impact of CRHPVN neuron activation is compromised by the pulmonary chemical sympathectomy or inhibition of the β2-adrenergic receptor. These protective effects were dependent on sympathetic nerves, with norepinephrine released locally to modulate neutrophil functions via β2-AR–β-arrestin2 signaling, inhibiting the NF-κB pathway. Our findings reveal a brain-lung axis that regulates immune responses in ALI, suggesting novel therapeutic targets for ALI and ARDS.
Project description:Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe conditions with high morbidity and mortality, and effective treatments are limited. Neuroimmune interactions play a critical role in lung homeostasis, but it remains unclear if specific brain regions regulate lung inflammation. Here, we unveil the critical role of neuroimmune signaling in ALI, focusing on the regulatory function of corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus (PVN) of the hypothalamus. Using viral tracing, chemogenetic modulation, and pharmacological interventions in mouse models of ALI induced by intranasal lipopolysaccharide and cecal ligation and puncture (CLP), we found that lung injury activated CRHPVN neurons that projected to the lung. Activation of these neurons protected mice from ALI and death, reducing neutrophil infiltration and effector functions in the lung. In contrast, inhibiting CRHPVN neurons exacerbated ALI. Notably, the beneficial impact of CRHPVN neuron activation is compromised by the pulmonary chemical sympathectomy or inhibition of the β2-adrenergic receptor. These protective effects were dependent on sympathetic nerves, with norepinephrine released locally to modulate neutrophil functions via β2-AR–β-arrestin2 signaling, inhibiting the NF-κB pathway. Our findings reveal a brain-lung axis that regulates immune responses in ALI, suggesting novel therapeutic targets for ALI and ARDS.
Project description:<p>Acute lung injury (ALI) is a lung disease characterized by an excessive inflammatory response and damage to lung epithelial cells. Atractylodin (ATL) is the main active component of Atractylodes lancea (Thunb.) DC., which has good anti-inflammatory activity and protects the integrity of the epithelial cell barrier. However, the efficacy of ATL in the treatment of ALI and its mechanism are unclear. We investigated the efficacy of ATL in treating ALI in vivo and in vitro, and explored its targets and mechanisms of action from metabolic and signaling pathways. The results showed that, in vivo, ATL significantly reduced the wet-dry ratio of lungs of rats with ALI, improved the pathological changes, reduced the aggregation and activation of neutrophils and macrophages in the lungs, and lowered the expression of the inflammatory factors, MCP-1, and MPO. The transcriptomics results suggested that ATL exerts its therapeutic effects by modulating the HIF-1 signaling pathway and metabolic processes. Metabolomics results showed that ATL mainly affected the processes of lactose degradation and galactose metabolism. Combined metabolomic and transcriptomic analyses showed that ASAH3L, a gene related to galactose metabolism, was regulated by ATL, and further experiments demonstrated that ATL reduced the expression of ASAH3L and ROS thereby inhibiting the activation of the HIF-1 signaling pathway. Overexpression of ASAH3L reversed the therapeutic effect of ATL in rats with ALI. In conclusion, ATL can reduce inflammation by inhibiting activating the HIF-1 signaling pathway and targeting ASAH3L to regulate galactose metabolism, thereby alleviating ALI.</p>
Project description:Acute Lung Injury (ALI) can cause Acute Respiratory Distress Syndrome (ARDS), a lethal condition with limited treatment options and currently a common global cause of death due to COVID-19-induced ALI. ARDS secondary to Transfusion-Related Acute Lung Injury (TRALI) has been recapitulated pre-clinically by anti-MHC-I antibody administration to LPS-primed mice. In this model, we demonstrated that inhibitors of PTP1B, a protein tyrosine phosphatase that regulates signaling pathways of fundamental importance to homeostasis and inflammation, prevented lung injury and increased survival. Treatment with PTP1B inhibitors attenuated the aberrant neutrophil function that drives ALI, and was associated with release of myeloperoxidase, suppression of Neutrophil Extracellular Trap (NET) formation, and inhibition of neutrophil migration. Mechanistically, reduced signaling through the CXCR4 chemokine receptor, particularly to the activation of mTOR, was essential for these effects, linking PTP1B in hibition to promoting an aged neutrophil phenotype. Considering dysregulated activation of neutrophils is implicated in sepsis and can cause collateral tissue damage, we demonstrated also that PTP1B inhibitors improved survival and ameliorated lung injury in the LPS-induced sepsis model. Our data highlight PTP1B inhibition for prevention of TRALI and ARDS from multiple etiologies.
Project description:With advances in supportive therapy in the last two decades, mortality rates from ALI/ARDS have improved somewhat, but remain around 30 to 40% with significant morbidity in survivors. Several promising treatments are in various stages of evaluation, but many have failed to prove beneficial in large randomized clinical trials (RCT). The first definitive step forward in ALI therapeutics occurred recently as a result of a large RCT demonstrating a mortality decrease from 40 to 31% with the use of low-volume ventilation strategies. From this, it is clear that the opportunity for successful intervention in ALI exists. However, therapeutic advances remain frustrated by the lack of complete understanding of ALI pathophysiology. This stresses the importance of integrating basic and clinical research of the molecular pathogenesis of this disease. The conclusions of a recent National Heart, Lung, and Blood Institute (NHLBI) Working Group on ALI support this type of research as a priority for future investigations of ALI. One of the areas of research given priority by this ALI Working Group is the issue of ALI severity progression and the role of cells of innate immunity in this process. Currently, the processes that determine which ALI patients progress to ARDS and which do not are unclear. As with many phenotype differences, there is most likely a genetic component involved. The basis for this has been demonstrated. For example, a surfactant protein B (SP-B) polymorphism appears to increase a patientâ??s risk of developing ALI from pneumonia. Additionally, a polymorphism in the promoter region of the gene for interleukin-6 (IL-6) has been associated with a poor prognosis in patients with ARDS. Understanding the intracellular processes of these genes and the cells expressing them in ALI progression could lead to the identification of molecular markers of ALI severity and eventually to the development of targeted therapies. An examination of genetically uniform animals will provide a clearer insight into the interaction between immune cells in ALI progression as well as guide future human experiments. Experiment Overall Design: Specific Aim 1. We will prospectively collect and bank RNA from peripheral blood CD4+ T lymphocytes (Th1 and Th2 subsets) and platelets from cecal ligation and puncture-treated BALB/c mice using a negative selection technique. Specific Aim 2. Four mice will undergo whole blood sampling at each of 3 time points (t = 0, 24, and 48 hours). Time 0 represents the point of CLP. Specific Aim 3. The temporal series of 3 cell types pooled within each time point will be expression profiled (3 time points x 3 cell types x MOE430A array = 9 profiles) in order to generate a map of potential cell-cell interactions and a prioritization model for examining these further.
Project description:<p>Acute Respiratory Distress Syndrome (ARDS)/ Acute Lung Injury (ALI) is a syndrome defined by the presence of acute hypoxemic respiratory failure, bilateral pulmonary infiltrates on chest radiograph, a known clinical risk factor (e.g. sepsis, pneumonia, trauma, gastric fluid aspiration, pancreatitis, massive transfusion), and the absence of physiologic or clinical evidence of congestive heart failure.</p> <p>The Identification of SNPs Predisposing to Altered ALI Risk (iSPAAR) study is a multi-institutional cooperative study, funded through the NHLBI Recovery Act, that assembled samples and phenotype information from existing cohorts.</p> <p>The consortium included samples from patients with ARDS from the NIH NHLBI ARDS Clinical Trials Network (ARDSNet). Samples were obtained from 3 interventional treatment trials in patients with ARDS, including the Fluid and Catheter Treatment Trial (FACTT), the Albuterol to Treat Acute Lung Injury (ALTA) trial, and the Omega-3 Fatty Acid/Antioxidant Supplementation for ALI trial (Omega).</p> <p>In addition to ARDSnet samples, samples from the other cohorts included cases of established ARDS but also controls: critically ill patients who were at-risk for ARDS but who did not develop ARDS during their hospital course. These cohorts included the Molecular Epidemiology of Acute Respiratory Distress (MEA) Study enrolled at the Harvard University/Massachusetts General Hospital, the Systemic Inflammatory Immune Response Syndrome (SIRS) Patient Database and ICU Traumatic Injury cohorts from Harborview Medical Center, and cohorts collected from the ALI research programs at the University of Pennsylvania and the University of California, San Francisco.</p> <p><b>The Cohort is utilized in the following dbGaP sub-studies.</b> To view genotypes, other molecular data, and derived variables collected in these sub-studies, please click on the following sub-studies below or in the "Sub-studies" box located on the right hand side of this top-level study page <a href="study.cgi?study_id=phs000631">phs000631</a> ARDSnet iSPAAR Consortium. <ul> <li><a href="study.cgi?study_id=phs000334">phs000334</a> ESP_LungGO_ALI </li> <li><a href="study.cgi?study_id=phs000686">phs000686</a> ALI_GeneticRisk </li> </ul> </p>