Project description:Vicious circle of some key proteins is critical in the process of tumor development. Nevertheless, the mechanism of how the epigenetic modifiers are involved in was seldom reported and has not been clearly illustrated. We found the expression of lysine specific demethylase 1 (LSD1), the first identified histone lysine demethylase, is positively correlated with transforming growth factor beta 1 (TGF β1) in gastric cancer tissues and can be promoted by TGF β1 activated (p-EKR)-(NF-κB)-p300 signaling pathway, which resulted in the progression of epithelial-mesenchymal transition (EMT) in human gastric cancer cells. On the other hand, abrogation of LSD1 leads to the down regulation of TGF β1 as well as the EMT. But in benign cells, this circle was blocked by TGF β1 induced inactivation of ERK, which suggested the distinct roles of TGF β1 against LSD1 in gastric cancer cells and benign cells. This vicious cycle may illustrate a novel mechanism for EMT in gastric cancer mediate by TGF β1 and LSD1 but not in benign cells and may serve as a new strategy for the prevention of EMT for gastric cancer.
Project description:Vicious circle of some key proteins is critical in the process of tumor development. Nevertheless, the mechanism of how the epigenetic modifiers are involved in was seldom reported and has not been clearly illustrated. We found the expression of lysine specific demethylase 1 (LSD1), the first identified histone lysine demethylase, is positively correlated with transforming growth factor beta 1 (TGF β1) in gastric cancer tissues and can be promoted by TGF β1 activated (p-EKR)-(NF-κB)-p300 signaling pathway, which resulted in the progression of epithelial-mesenchymal transition (EMT) in human gastric cancer cells. On the other hand, abrogation of LSD1 leads to the down regulation of TGF β1 as well as the EMT. But in benign cells, this circle was blocked by TGF β1 induced inactivation of ERK, which suggested the distinct roles of TGF β1 against LSD1 in gastric cancer cells and benign cells. This vicious cycle may illustrate a novel mechanism for EMT in gastric cancer mediate by TGF β1 and LSD1 but not in benign cells and may serve as a new strategy for the prevention of EMT for gastric cancer. Nuclear extracts prepared from MGC803 cells stably expressing Lenti-CAS9-sgRNA-puro for LSD1 or empty vector were used in immunoprecipitation reactions with antibodies against H3K4me2 and H3K9me2. Sequencing libraries were prepared using the TruSeq DNA Sample Prep Kit (Illumina) and sequencing was performed on a HiSeq2000 (Illumina).
Project description:Venkatraman2012 - Interplay between PLS and TSP1 in TGF-β1 activation
The interplay between PLS (Plasmin) and TSP1 (Thrombospondin-1) in TGF-β1 (Transforming growth factor-β1)is shown using mathematical modelling and in vitro
experimentents.
This model is described in the article:
Plasmin triggers a switch-like decrease in thrombospondin-dependent activation of TGF-β1.
Venkatraman L, Chia SM, Narmada BC, White JK, Bhowmick SS, Forbes Dewey C Jr, So PT, Tucker-Kellogg L, Yu H.
Biophys J. 2012 Sep 5;103(5):1060-8.
Abstract:
Transforming growth factor-β1 (TGF-β1) is a potent regulator of extracellular matrix production, wound healing, differentiation, and immune response, and is implicated in the progression of fibrotic diseases and cancer. Extracellular activation of TGF-β1 from its latent form provides spatiotemporal control over TGF-β1 signaling, but the current understanding of TGF-β1 activation does not emphasize cross talk between activators. Plasmin (PLS) and thrombospondin-1 (TSP1) have been studied individually as activators of TGF-β1, and in this work we used a systems-level approach with mathematical modeling and in vitro experiments to study the interplay between PLS and TSP1 in TGF-β1 activation. Simulations and steady-state analysis predicted a switch-like bistable transition between two levels of active TGF-β1, with an inverse correlation between PLS and TSP1. In particular, the model predicted that increasing PLS breaks a TSP1-TGF-β1 positive feedback loop and causes an unexpected net decrease in TGF-β1 activation. To test these predictions in vitro, we treated rat hepatocytes and hepatic stellate cells with PLS, which caused proteolytic cleavage of TSP1 and decreased activation of TGF-β1. The TGF-β1 activation levels showed a cooperative dose response, and a test of hysteresis in the cocultured cells validated that TGF-β1 activation is bistable. We conclude that switch-like behavior arises from natural competition between two distinct modes of TGF-β1 activation: a TSP1-mediated mode of high activation and a PLS-mediated mode of low activation. This switch suggests an explanation for the unexpected effects of the plasminogen activation system on TGF-β1 in fibrotic diseases in vivo, as well as novel prognostic and therapeutic approaches for diseases with TGF-β dysregulation.
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Project description:Epithelial-mesenchymal transition (EMT) has recently been recognized as a key element of cell invasion, migration, metastasis, and drug resistance in several types of cancer, including non-small cell lung cancer (NSCLC). Our aim was to clarify microRNA (miRNA) -related mechanisms underlying EMT followed by acquired resistance to epidermal growth factor receptor tyrosine-kinase inhibitor (EGFR-TKI) in NSCLC. MiRNA expression profiles were examined before and after transforming growth factor-beta1 (TGF-β1) exposure in four human adenocarcinoma cell lines with or without EMT. Correlation between expressions of EMT-related miRNAs and resistance to EGFR-TKI gefitinib was evaluated. MiRNA array and quantitative RT-PCR revealed that TGF-β1 significantly induced overexpression of miR-134, miR-487b, and miR-655, which belong to the same cluster located on chromosome 14q32, in lung adenocarcinoma cells with EMT. MAGI2 (membrane-associated guanylate kinase, WW and PDZ domain-containing protein 2), a predicted target of these miRNAs and a scaffold protein required for PTEN (phosphatase and tensin homolog), was diminished in A549 cells with EMT after the TGF-β1 stimulation. Overexpression of miR-134 and miR-487b promoted the EMT phenomenon and affected the drug resistance to gefitinib, whereas knockdown of these miRNAs inhibited the EMT process and reversed TGF-β1-induced resistance to gefitinib. Our study demonstrated that the miR-134/487b/655 cluster contributed to the TGF-β1-induced EMT phenomenon and affected the resistance to gefitinib by directly targeting MAGI2, whose suppression subsequently caused loss of PTEN stability in lung cancer cells. The miR-134/miR-487b/miR-655 cluster may be new therapeutic targets in advanced lung adenocarcinoma patients, depending on the EMT phenomenon.
Project description:Idiopathic pulmonary fibrosis (IPF) is the prototypic progressive fibrotic lung disease with a median survival of 2-4 years. Injury to and/or dysfunction of alveolar epithelium are strongly implicated in IPF disease initiation, but what factors determine why fibrosis progresses rather than normal tissue repair occurs remain poorly understood. We previously demonstrated that ZEB1-mediated epithelial-mesenchymal transition (EMT) in human alveolar epithelial type II (ATII) cells augments TGF-β-induced profibrogenic responses in underlying lung fibroblasts by paracrine signalling. Here we investigated bi-directional epithelial-mesenchymal crosstalk and its potential to drive fibrosis progression. RNA sequencing (RNA-seq) of lung fibroblasts exposed to conditioned media from ATII cells undergoing RAS-induced EMT identified many differentially expressed genes including those involved in cell migration and extracellular matrix (ECM) regulation. We confirmed that paracrine signalling between AS-activated ATII cells and fibroblasts augmented fibroblast recruitment and demonstrated that this involved a ZEB1-tissue plasminogen activator (tPA) axis. In a reciprocal fashion, paracrine signalling from TGF-β-activated lung fibroblasts or IPF fibroblasts induced RAS activation in ATII cells, at least partially via the secreted protein, SPARC. Together these data identify that aberrant bi-directional epithelial-mesenchymal crosstalk in IPF drives a chronic feedback loop that maintains a wound-healing phenotype and provides self-sustaining pro-fibrotic signals.
Project description:To identify the dysregulated lncRNA and mRNA expression in ARPE-19 cells underwent EMT, we established a TGF-β1 induced EMT model of ARPE-19 cells. ARPE-19 cells were treated with or without 10 ng/ml TGF-β1 for 48 h. Total RNA are extracted and subjected to microarray assay (Arraystar Human LncRNA Microarray V3.0)
Project description:The inflammatory response after spinal cord injury (SCI) is an important contributor to secondary damage. Infiltrating macrophages can acquire a spectrum of activation states, however, the microenvironment at the SCI site favors macrophage polarization into a pro-inflammatory phenotype, which is one of the reasons why macrophage transplantation has failed. In this study, we investigated the therapeutic potential of the macrophage secretome for SCI recovery. We investigated the effect of the secretome in vitro using peripheral and CNS-derived neurons and human neural stem cells. Moreover, we perform a pre-clinical trial using a SCI compression mice model and analyzed the recovery of motor, sensory and autonomic functions. Instead of transplanting the cells, we injected the paracrine factors and extracellular vesicles that they secrete, avoiding the loss of the phenotype of the transplanted cells due to local environmental cues. We demonstrated that different macrophage phenotypes have a distinct effect on neuronal growth and survival, namely, the alternative activation with IL-10 and TGF-β1 (M(IL-10+TGF-β1)) promotes significant axonal regeneration. We also observed that systemic injection of soluble factors and extracellular vesicles derived from M(IL-10+TGF-β1) macrophages promotes significant functional recovery after compressive SCI and leads to higher survival of spinal cord neurons. Additionally, the M(IL-10+TGF-β1) secretome supported the recovery of bladder function and decreased microglial activation, astrogliosis and fibrotic scar in the spinal cord. Proteomic analysis of the M(IL-10+TGF-β1)-derived secretome identified clusters of proteins involved in axon extension, dendritic spine maintenance, cell polarity establishment, and regulation of astrocytic activation. Overall, our results demonstrated that macrophages-derived soluble factors and extracellular vesicles might be a promising therapy for SCI with possible clinical applications.