Development of gene expression signatures of murine silicosis in the lung CD45-negative tissue cells from CCR2 knockout mice
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ABSTRACT: Pulmonary fibrosis (PF) is an intractable disorder with a poor prognosis. Although macrophages are known to promote both the initiation and resolution of lung injury in reversible PF, it remains unclear how macrophages contribute to the progression of chronic PF. The object of this study was to investigate the role of inflammatory monocyte-derived macrophages (MMs) in the transcriptomic signatures of the lung tissue cells from murine progressive PF. We collected CD45-negative lung tissue cells from silica-treated CCR2 knockout and WT mice on days 28, 40 and untreated mice on day 0 post-aspiration and performed global transcriptome analyses using microarray. Data were analyzed by fuzzy c-means or CLICK clustering, gene set enrichment analysis, and network analyses. Global transcriptome analyses revealed that MM deficiency potentiated changes in gene-expression in tissue cells, closely matching trends seen in human chronic PF. Regulatory network analysis of transcriptome data suggested that MM-derived factors, such as tumor necrosis factor-α, were involved in the suppression of tissue remodeling-related gene expression. Overall, these results demonstrate that MMs suppress tissue cell responses and associated pathology in progressive PF.
Project description:Although recent progressions have provided significant mechanistic insights into the pathogenesis of pulmonary fibrosis (PF), few of anti-PF therapeutics show certain promise for this devastating disease. Chronic or repeated lung injury results in chronic inflammation, which functions as a major driven force to promote PF development. Here we report that chronic lung injury inactivates ubiquitin-modifying enzyme A20 to cause a progressive accumulation of transcription factor C/EBPb in macrophages, which produce a number of pro-fibrotic factors to promote PF development. Elevated GSK-3b expression, in response to chronic lung injury, interacts with and phosphorylates A20 to suppress C/EBPb degradation in macrophages. Enforced expression of A20 or pharmacological acceleration of C/EBPb degradation by a peptide restores the A20 activity and provides potent therapeutic efficacy against experimental PF. Our studies reveal a regulatory mechanism of the GSK-3b-A20-C/EBPb axis in alveolar macrophages, by targeting which can treat PF and fibroproliferative lung diseases.
Project description:Although recent progressions have provided significant mechanistic insights into the pathogenesis of pulmonary fibrosis (PF), few of anti-PF therapeutics show certain promise for this devastating disease. Chronic or repeated lung injury results in chronic inflammation, which functions as a major driven force to promote PF development. Here we report that chronic lung injury inactivates ubiquitin-modifying enzyme A20 to cause a progressive accumulation of transcription factor C/EBPb in macrophages, which produce a number of pro-fibrotic factors to promote PF development. Elevated GSK-3b expression, in response to chronic lung injury, interacts with and phosphorylates A20 to suppress C/EBPb degradation in macrophages. Enforced expression of A20 or pharmacological acceleration of C/EBPb degradation by a peptide restores the A20 activity and provides potent therapeutic efficacy against experimental PF. Our studies reveal a regulatory mechanism of the GSK-3b-A20-C/EBPb axis in alveolar macrophages, by targeting which can treat PF and fibroproliferative lung diseases.
Project description:Pulmonary fibrosis (PF) is a progressive fibrotic disease with a poor prognosis and suboptimal therapeutic options. The complement molecule C1q, which plays an important role in the phagocytic capacity of macrophages, has recently been reported to exacerbate several fibrosis-related diseases. On the other hand, there are still no reports in PF. Here, we analyzed the effect of C1q treatment on lung fibroblasts.
Project description:We recently identified a gene module of 87 genes co-expressed with MCL1 (MCL1-M), a critical regulator of plasma cell survival. MCL1-M captures both MM cell-intrinsically acting signals and the signals regulating the interaction between MM cells with bone marrow microenvironment. MM can be clustered into MCL1-M high and MCL1-M low subtypes. While the MCL1-M high MMs are enriched in a preplasmablast signature, the MCL1-M low MMs are enriched in B cell-specific genes. In multiple independent datasets, MCL1-M high MMs exhibited poorer prognosis compared to MCL1-M low MMs. Re-analysis of the phase III HOVON-65/GMMG-HD4 showed that only MCL1-M MMs, but not MCL1-M low MMs, benefited from bortezomib-based treatment. To translate the MCL1-M clustering scheme into a platform for individual diagnosis, we refined the classifier genes and developed a support vector machine-based algorithm. Individual MMs with transcriptome assessed at the RNA-seq or U133 plus 2.0 array platform can be robustly assigned as the MCL1-M high or low subtype with high confidence. Analyses of the MM samples in the HOVON-65/GMMG-HD4 trial and APEX trial reinforce that only MCL1-M high MMs benefit from bortezomib-based treatment with a hazard ratio of 0.58 (P = 0.010) and 0.47 (P = 0.009), respectively. Thus, MCL1-M based subtyping assigns MMs into prognostic and predictive molecular subtypes driven by subtype-specific pathogenic pathways.
Project description:Pulmonary fibrosis (PF) is a chronic, progressive condition that represents the end-stage of many interstitial lung diseases (ILDs). Single-cell transcriptomic studies have revealed disease-emergent epithelial, fibroblast, and macrophage cell types/states in PF lungs, but the spatial contexts wherein these cells contribute to disease pathogenesis has remained uncertain. Using image-based spatial transcriptomics to profile gene expression changes in-situ across 28 lung samples from control and PF lungs, we characterized the expression of 343 genes in over 1 million nuclei at subcellular resolution. Using both cell-based and cell-agnostic approaches, we observed a diversity of distinct molecularly-defined spatial niches in control and PF lungs. Overlaying these computationally-defined niches with disease-associated histopathologic features, we identified novel patterns of dysregulation in alveoli informed by spatial context. We computationally segmented individual air spaces and using cell composition, we ordered airspaces from homeostatic to most dysregulated. Using this ordering we identified a series of stepwise molecular changes associated with progressive distal lung remodeling. Together, these results advance our understanding of the molecular programs underlying progressive PF.
Project description:Pulmonary fibrosis (PF) is a chronic, progressive condition that represents the end-stage of many interstitial lung diseases (ILDs). Single-cell transcriptomic studies have revealed disease-emergent epithelial, fibroblast, and macrophage cell types/states in PF lungs, but the spatial contexts wherein these cells contribute to disease pathogenesis has remained uncertain. Using image-based spatial transcriptomics to profile gene expression changes in-situ across 28 lung samples from control and PF lungs, we characterized the expression of 343 genes in over 1 million nuclei at subcellular resolution. Using both cell-based and cell-agnostic approaches, we observed a diversity of distinct molecularly-defined spatial niches in control and PF lungs. Overlaying these computationally-defined niches with disease-associated histopathologic features, we identified novel patterns of dysregulation in alveoli informed by spatial context. We computationally segmented individual air spaces and using cell composition, we ordered airspaces from homeostatic to most dysregulated. Using this ordering we identified a series of stepwise molecular changes associated with progressive distal lung remodeling. Together, these results advance our understanding of the molecular programs underlying progressive PF.
Project description:Pulmonary fibrosis (PF) is a progressive fibrotic disease with a poor prognosis and suboptimal therapeutic options. Macrophages have been implicated in PF; however, the roles of macrophage subsets, particularly interstitial macrophages (IM), remain unknown. To address this issue, we performed time-series single-cell RNA sequencing (scRNA-seq) analysis in silica-induced PF model mice and clarify the characteristics of IM. In addition, to elucidate the origin of IM, we used CCR2-/- mice which supressed classical monocyte infiltration.
Project description:Pulmonary fibrosis (PF) is associated with many chronic lung diseases including Systemic sclerosis (SSc), Idiopathic Pulmonary Fibrosis (IPF) and Cystic Fibrosis (CF) which are characterized by the progressive accumulation of stromal cells and formation of scar tissue. Pulmonary fibrosis is a dysregulated response to alveolar injury which causes a progressive decline in lung function and refractory to current pharmacological therapies. Airway and alveolar epithelial cells and stromal cells contribute to pulmonary fibrosis but the cell-specific pathways and gene networks that are responsible for the pathophysiology are unknown. Recent animals models generated in our lab demonstrate clinical phenotypes seen in human fibrotic disease. The mouse model of transforming growth factor-? (TGF?)-induced fibrosis include conditionally expressing TGF? in the lung epithelium under control of the CCSP promoter driving rtTA expression (CCSP/TGF?). This allow the TGF? is only expressed in airway and alveolar epithelial cells and only when mice fed doxycycline (Dox). Similar to PF in humans, TGF? mice on Dox developed a progressive and extensive adventitial, interstitial and pleural fibrosis with a decline in lung mechanics. Thus, the TGF? transgenic mouse is a powerful model to determine lung cell-specific molecular signatures involved in pulmonary fibrosis. In this study, we sought to determine changes in the transcriptome during TGF?-induced pulmonary fibrosis. Our results showed that several pro-fibrotic genes increased in the lungs of TGF? mice. This study demonstrates that WT1 network gene changes associated with fibrosis and myfibroblast accumulation and thus may serve as a critical regulator fibrotic lung disease. mRNA profiles of CCSP/- and CCSP/TGFalpha mice treated with Dox
Project description:Understanding how the genetic control of gene expression varies between cell types and contexts is key for our understanding of complex traits including disease. To this end, we leveraged single cell RNA sequencing (scRNA-seq) to characterize the genetic architecture of gene regulation in an organ with one of the most cellularly diverse organs, the human lung. We profile these effects across two conditions, tissue samples from healthy controls and patients with pulmonary fibrosis (PF), a chronic, progressive condition characterized by the scarring of lung tissue. In total, we have generated expression profiles of 475,047 cells from primary human lung tissue from 116 individuals, including 67 with PF and 49 unaffected donors. Employing a pseudo-bulk approach, we have mapped expression quantitative trait loci (eQTL) across 38 cell types, identifying shared and cell type-specific effects. Further, we identify disease-interaction eQTL demonstrating this class of associations are more likely to be cell-type specific and linked to key drivers of dysregulation in PF. Finally, we connect PF risk variants implicated by genome-wide association studies to their regulatory targets in disease-relevant cell types. This study represents the first use of scRNA-seq to identify cell type level eQTL in the human lung, and one of only a small number of studies to carry out these characterizations in solid tissues. These results provide valuable insights into lung biology and disease risk.
Project description:Pulmonary fibrosis (PF) is a progressive fibrotic disease with a poor prognosis and suboptimal therapeutic options. The complement molecule C1q, which plays an important role in the phagocytic capacity of macrophages, has recently been reported to exacerbate several fibrosis-related diseases. On the other hand, there are still no reports in PF. Here, we analyzed gene expression changes of C1q-administrated murine lungs.