Project description:Inflammation of epithelial structures frequently leads to disease at distal organs, but the mechanism responsible for this is unknown. We report evidence that digestion of hyaluronan in the extracellular matrix signals distal stromal cells to become primed for increased inflammation. By applying transgenic mouse models and single cell RNA sequencing of mouse and human tissues we demonstrate that skin injury or infection promotes an adipogenic response in distinct populations of distant submucosal fibroblasts of the colon. This response can be recapitulated without skin inflammation by expression of hyaluronidase in skin that promotes a highly amplified and frequently fatal host response to intestinal injury. Our results uncover an innate system of communication between epithelial stroma that is not initiated by immunocyte trafficking or cytokine signaling.
Project description:Inflammation of epithelial structures frequently leads to disease at distal organs, but the mechanism responsible for this is unknown. We report evidence that digestion of hyaluronan in the extracellular matrix signals distal stromal cells to become primed for increased inflammation. By applying transgenic mouse models and single cell RNA sequencing of mouse and human tissues we demonstrate that skin injury or infection promotes an adipogenic response in distinct populations of distant submucosal fibroblasts of the colon. This response can be recapitulated without skin inflammation by expression of hyaluronidase in skin that promotes a highly amplified and frequently fatal host response to intestinal injury. Our results uncover an innate system of communication between epithelial stroma that is not initiated by immunocyte trafficking or cytokine signaling.
Project description:Background: The extracellular matrix provides organizational context for solid organs. During disease, such as acute myocardial infarction, the composition of the extracellular matrix changes remarkably. One of the most notable changes in the extracellular matrix is in the accumulation of collagen; however, hyaluronan rivals collagen in terms of its abundance. Yet, the extent to which specific cells and enzymes may contribute to such accumulation has been largely unexplored. Here, we hypothesized that activated cardiac fibroblasts produce hyaluronan via hyaluronan synthase 2 (HAS2). Methods and Results: Using immunofluorescence, biochemical extraction, and ELISA, we show that hyaluronan accumulates following myocardial infarction and persists through at least four weeks. Our analyses of failing heart RNA sequencing data suggest fibroblasts are the cells most changed in expression of HAS2. Given these insights, we used HAS2 gain- and loss-of-function approaches to examine the extent to which activated cardiac fibroblasts produced hyaluronan. TGF-induced activation of fibroblasts caused a significant increase in Has2 mRNA and concomitant accumulation of hyaluronan greater than 1 MDa in size. Deletion of Has2 abrogated TGF-induced production of hyaluronan. In addition, overexpression of Has2 was sufficient to cause an increase in hyaluronan accumulation in the absence of TGF-induced activation. Given the magnitude of hyaluronan production, and that hyaluronan has been reported to have biologic activity, we then queried whether the primary functions of fibroblasts (proliferation, migration, and collagen production) were impacted by hyaluronan treatment. Our data indicated negligible impacts of Has2 on proliferation, migration, and collagen production. Exposing fibroblasts to exogenous hyaluronan also had minimal impact on fibroblasts. We also assessed whether fibroblast-borne Hyal2 plays a role in degradation of hyaluronan, and our data indicated little impact of Hyal2 on hyaluronan accumulation (or even any impacts on the transcriptional profile of fibroblasts). Conclusion: Activated fibroblasts produce high molecular weight hyaluronan, and the production of hyaluronan depends on Has2. The robust production of hyaluronan by fibroblasts does not appear to impact fibroblast function.
Project description:Background: The extracellular matrix provides organizational context for solid organs. During disease, such as acute myocardial infarction, the composition of the extracellular matrix changes remarkably. One of the most notable changes in the extracellular matrix is in the accumulation of collagen; however, hyaluronan rivals collagen in terms of its abundance. Yet, the extent to which specific cells and enzymes may contribute to such accumulation has been largely unexplored. Here, we hypothesized that activated cardiac fibroblasts produce hyaluronan via hyaluronan synthase 2 (HAS2). Methods and Results: Using immunofluorescence, biochemical extraction, and ELISA, we show that hyaluronan accumulates following myocardial infarction and persists through at least four weeks. Our analyses of failing heart RNA sequencing data suggest fibroblasts are the cells most changed in expression of HAS2. Given these insights, we used HAS2 gain- and loss-of-function approaches to examine the extent to which activated cardiac fibroblasts produced hyaluronan. TGF-induced activation of fibroblasts caused a significant increase in Has2 mRNA and concomitant accumulation of hyaluronan greater than 1 MDa in size. Deletion of Has2 abrogated TGF-induced production of hyaluronan. In addition, overexpression of Has2 was sufficient to cause an increase in hyaluronan accumulation in the absence of TGF-induced activation. Given the magnitude of hyaluronan production, and that hyaluronan has been reported to have biologic activity, we then queried whether the primary functions of fibroblasts (proliferation, migration, and collagen production) were impacted by hyaluronan treatment. Our data indicated negligible impacts of Has2 on proliferation, migration, and collagen production. Exposing fibroblasts to exogenous hyaluronan also had minimal impact on fibroblasts. We also assessed whether fibroblast-borne Hyal2 plays a role in degradation of hyaluronan, and our data indicated little impact of Hyal2 on hyaluronan accumulation (or even any impacts on the transcriptional profile of fibroblasts). Conclusion: Activated fibroblasts produce high molecular weight hyaluronan, and the production of hyaluronan depends on Has2. The robust production of hyaluronan by fibroblasts does not appear to impact fibroblast function.
Project description:Background: The extracellular matrix provides organizational context for solid organs. During disease, such as acute myocardial infarction, the composition of the extracellular matrix changes remarkably. One of the most notable changes in the extracellular matrix is in the accumulation of collagen; however, hyaluronan rivals collagen in terms of its abundance. Yet, the extent to which specific cells and enzymes may contribute to such accumulation has been largely unexplored. Here, we hypothesized that activated cardiac fibroblasts produce hyaluronan via hyaluronan synthase 2 (HAS2). Methods and Results: Using immunofluorescence, biochemical extraction, and ELISA, we show that hyaluronan accumulates following myocardial infarction and persists through at least four weeks. Our analyses of failing heart RNA sequencing data suggest fibroblasts are the cells most changed in expression of HAS2. Given these insights, we used HAS2 gain- and loss-of-function approaches to examine the extent to which activated cardiac fibroblasts produced hyaluronan. TGF-induced activation of fibroblasts caused a significant increase in Has2 mRNA and concomitant accumulation of hyaluronan greater than 1 MDa in size. Deletion of Has2 abrogated TGF-induced production of hyaluronan. In addition, overexpression of Has2 was sufficient to cause an increase in hyaluronan accumulation in the absence of TGF-induced activation. Given the magnitude of hyaluronan production, and that hyaluronan has been reported to have biologic activity, we then queried whether the primary functions of fibroblasts (proliferation, migration, and collagen production) were impacted by hyaluronan treatment. Our data indicated negligible impacts of Has2 on proliferation, migration, and collagen production. Exposing fibroblasts to exogenous hyaluronan also had minimal impact on fibroblasts. We also assessed whether fibroblast-borne Hyal2 plays a role in degradation of hyaluronan, and our data indicated little impact of Hyal2 on hyaluronan accumulation (or even any impacts on the transcriptional profile of fibroblasts). Conclusion: Activated fibroblasts produce high molecular weight hyaluronan, and the production of hyaluronan depends on Has2. The robust production of hyaluronan by fibroblasts does not appear to impact fibroblast function.
Project description:In the present study, we analyzed single-cell multi-omics data from psoriasis patients and healthy individuals and found that more fibroblast-macrophage communication was present in the dermis of psoriasis lesions, exacerbating psoriasis progression. A natural product library was used to screen for a small molecule compound, celastrol, that could interfere with fibroblast-macrophage communication. It was demonstrated that celastrol targeted low-denisity lipoprotein receptor-related protein 1 (LRP1) to inhibit fibroblast secretion of CCL2 and inhibited psoriasis progression by reducing its recruitment to macrophages, thereby blocking communication between the two cells. Moreover, conditional knockdown of LRP1 by fibroblasts significantly improved psoriasis in mice, suggesting that LRP1 may be an important target for the treatment of psoriasis.
Project description:Single-cell RNA sequencing (scRNA-seq) was performed to investigate fibroblast–myeloid cell crosstalk in lung fibrosis. The dataset includes murine lung macrophage–fibroblast cocultures or fibroblast monocultures, with macrophages derived from WT mice and fibroblasts from either WT or fibroblast-specific P2rx4 knockout (Pdgfrb-Cre: P2rx4 f/f) mice 7 days after bleomycin injury. Cells were captured using the Fluent Biosciences PIPseq platform. Data include gene–cell count matrices and support the study “Myeloid–mesenchymal crosstalk drives ARG1-dependent profibrotic metabolism via ornithine in lung fibrosis” (Yadav et al., 2025).