Transcriptome analysis of tendon derived from Piezo1 mutant mice
Ontology highlight
ABSTRACT: Tendon tissue growth is promoted by mechanical stimulation, but the mechanism is not well understood. Piezo1, a mechanical stress-responsive channel receptor, is expressed in tendon cells, and the fact that tendon tissue growth was accelerated in Piezo1 gain of function mice suggests that Piezo1 plays an important role in tendon tissue growth. RNA-seq of tendon tissues from these mice showed increased expression of tendon-related genes and decreased expression of muscle-related genes, suggesting that Piezo1 may play a role in maintaining and enhancing the properties of tendon cells.
Project description:Piezo1 is a mechanosensitive ion channel that has gained recognition for its role in regulating diverse physiological processes. However, the influence of Piezo1 in inflammatory disease, including infection and tumor-immunity, is not well-studied. We postulated that Piezo1 links physical forces to immune regulation in myeloid cells. We discovered signal transduction via Piezo1 in myeloid cells and established this channel as the primary sensor of mechanical stress in these cells. Global inhibition of Piezo1 was protective against both cancer and septic shock and resulted in a diminution in suppressive myeloid cells. Moreover, deletion of Piezo1 in myeloid cells protected against cancer and increased survival in poly-microbial sepsis. Mechanistically, we show that mechanical stimulation promotes Piezo1-dependent myeloid cell expansion by suppressing Rb. We further show Piezo1-mediated silencing of Rb is regulated via upregulation of HDAC2. Collectively, our work uncovers Piezo1 as a targetable immune checkpoint that drives immune-suppressive myelopoiesis in cancer and infectious disease.
Project description:Adhesion formation after flexor tendon repair remains a clinical problem. Early postoperative motion after tendon repair has been demonstrated to reduce adhesion formation while increasing tendon strength. It is hypothesized that during mobilization, tendon cells experience mechanical shear forces that alter their biology in a fashion that reduces scar formation but also activates key genes involved in tendon healing. To test this hypothesis, primary intrinsic tenocyte cultures were established from flexor tendons of 20 Sprague-Dawley rats and sheared at 50 rpm (0.41 Pa) using a cone viscometer for 6 and 12 hours. Total RNA was harvested and compared with time-matched unsheared controls using cDNA microarrays and Northern blot analysis. Microarray analysis demonstrated that mechanical shear stress induced an overall "antifibrotic" expression pattern with decreased transcription of collagen type I and collagen type III. Shear stress down-regulated profibrotic molecules in the platelet-derived growth factor, insulin-like growth factor, and fibroblast growth factor signaling pathways. In addition, shear stress induced an overall decrease in transforming growth factor (TGF)-beta signaling pathway molecules with down-regulation of TGF-beta2, TGF-beta3, TGF-RI, and TGF-RII expression. Moreover, sheared tendon cells increased expression of matrix metalloproteinases and decreased expression of tissue inhibitors of metalloproteinase, an expression pattern consistent with an antifibrotic increase in extracellular matrix degradation. However, up-regulation of genes implicated in tendon healing, specifically, vascular endothelial growth factor-A and several bone morphogenetic proteins. Interestingly, the known mechanoresponsive gene, TGF-beta1, also implicated in tendon healing, was differentially up-regulated by shear stress. Northern blot validation of our results for TGF-beta1, TGF-beta2, TGF-beta3, and collagen type I demonstrated direct correlation with microarray data. Groups of assays that are related as part of a time series. Computed
Project description:PIEZO1 is a mechanically-activated ion channel that contributes to flow sensing in vascular endothelium. Moreover, deletion of endothelial PIEZO1 was recently found to suppress activation of Notch1 target genes in hepatic microvascular endothelium. Here, because of the liver’s dominant role in lipid regulation, we set out to test the novel hypothesis that endothelial PIEZO1 regulates hepatic lipid homeostasis. We performed bulk RNA sequencing on PIEZO1-deleted mice exposed to chow and high fat diets. Our transcriptomics analysis reveal unexpected relevance to lipid and glucose homeostasis.
Project description:Piezo1 is a mechanoactive calcium ion channel and is expressed in skin cells. We used single cell RNA sequencing (ScRNAseq) to analyze the functions of mechanical sensing by Piezo1 in hair follicle cells.
Project description:In China, the incidence of fracture non-unions is relatively high. Impaired endochondral ossification may lead to nonunion due to improper mechanical loading. As a mechanosensitive ion channel protein, Piezo1mediates mechanical transduction and induces calcium inward flow. Our early study showed that the osteogenic and angiogenic capacity of chondrocytes was reduced, if Piezo1 gene was knocked out on chondrocytes. Moreover, the expression of mitochondrion translation related gene LARS2 was signaling increased. Therefore, we hypothesize that the mechanical loading may cause endochondral ossification through the Piezo1- LARS2 signaling pathway. We will use conditioned gene knockout mice and Peizo1 knockdown stable cell line to support the hypothesis. Our goals include investigating the changes of Piezo1 expression during endochondral ossification of femoral fracture healing in mice under mechanical loading; investigating the response of Piezo1 channels on chondrocytes to mechanical stimulation and its role and mechanism in regulating chondrocyte osteogenesis and angiogenesis, maintaining the normal mitochondrial function in vitro; analysing the key molecular and signal network downstream of Piezo1 through the multi-omics techniques; and exploring the response mechanism of Piezo1 under vibrating stimulus. This project aims to study the molecular mechanism of Piezo1-mediated force-biological information transition and its role in endochondral ossification. We hope it provides an effective intervention target for preventing and treating fracture nonunion.
Project description:To investigate the effect of Piezo1 in the apoptosis of anulus fibrous cells (AFCs) induced by mechanical stretch. We established AFCs in which Piezo1 channel has been knocked down by shRNA. We then performed gene expression profiling analysis using data obtained from RNA-seq of AFCs treated withpLVX-shRNA-Puro(Lv-Ctrl group) and AFCs treated with pLVX-shRNA-Puro-Piezo1(Lv-Piezo1 group).
Project description:Muscle satellite cells (MuSCs), skeletal muscle-resident stem cells, are crucial for regeneration of myofibers. Mechanical cues are thought to be important for activation and proliferation of muscle satellite cells, but the molecular entity that senses biophysical forces in MuSCs remains to be elucidated. In this study, we identified PIEZO1, a mechanosensitive ion channel that is activated by membrane tension, as a critical determinant for myofiber regeneration. We investigated gene profiles of Piezo1-deficient MuSCs to understand the role of PIEZO1 during myogenesis. Our results suggest that PIEZO1 governs the cytoskeletal reorganization to regulate cellular events in MuSCs (i.e., activation, cell-division, and proliferation) during skeletal muscle regeneration.
Project description:Platelet-derived growth factor receptor (PDGFR) signaling plays an important role in the embryonic formation of many different tissues. There is a family of PDGF isoforms which signal through the PDGF receptors α (PDGFRα) and β (PDGFRβ). PDGF regulates many key cellular processes of mesenchymal cell function including proliferation, differentiation, migration and extracellular matrix (ECM) synthesis. While PDGF has been used to enhance flexor tendon healing in vivo, its role in postnatal tendon growth has remained largely unexplored. To determine the importance of PDGFR signaling in postnatal tendon growth, we performed pharmacological blockade of PDGFRα and PDGFRβ, and then induced tendon growth via mechanical overload using the hindlimb synergist ablation model. Our hypothesis was that inhibition of PDGFR signaling will restrict normal growth of tendon tissue in response to mechanical loading.
Project description:The mechanisms by which physical forces regulate cells to determine complexities of vascular structure and function are enigmatic. Here we show the role the ion channel subunit Piezo1 (FAM38A). Disruption of mouse Piezo1 gene disturbed vascular development and was embryonic lethal within days of the heart beating to cause blood flow. Importance of Piezo channels as sensors of blood flow was indicated by Piezo1 dependence of shear stress-evoked ionic current and calcium influx in endothelial cells and the ability of exogenous Piezo1 to confer shear stress sensitivity on cells that otherwise lacked. Downstream of this calcium influx was proteoase activity and spatial organization of endothelial cells to the polarity of the applied force. Without Piezo1, normal endothelial cell organization was lacking. The data suggest Piezo1 channels as pivotal integrators of vascular architacture with physiological mechanical force.
Project description:Although cells of the immune system experience force and pressure throughout their lifecycle, almost nothing is known about how these mechanical processes regulate the immune response. Immune cells in highly mechanical organs, such as the lung, are constantly exposed to tonic and dynamically changing mechanical cues. Here using reverse genetics, we show that myeloid cells respond to force and alterations in cyclical hydrostatic pressure (CHP) via the mechanosensory ion channel (MSIC) PIEZO1. Unbiased RNA-sequencing from macrophages subjected to CHP reveals a striking state of proinflammatory reprogramming. We report a novel mechanosensory-immune signaling circuit which PIEZO1 initiates in response to CHP, activating c-JUN, upregulating Endothelin-1 (EDN1), and stabilizing HIF1α to facilitate a prolonged program of proinflammatory mediators. Using mice conditionally deficient of PIEZO1 in myeloid cells, and cellular depletion assays, we show infiltrating monocytes respond to cyclical force to recruit neutrophils and clear pulmonary Pseudomonas aeruginosa infection. Furthermore, myeloid PIEZO1 also drove lung pathology in a mouse model of pulmonary fibrosis. Our results demonstrate a novel environmental sensory axis that myeloid cells recognize to mount an inflammatory response, and is the first report showing a physiological role for PIEZO1 and mechanosensation in immunity.