Project description:DNAJB6 is a constitutively expressed member of the HSP40 family. It has been described as a negative regulator of breast tumor progression and a regulator of epithelial phenotype. Expression of DNAJB6 is reported to be compromised with tumor progression. However, factors responsible for its downregulation are still undefined. We used a knowledge-based screen for identifying miRNAs capable of targeting DNAJB6. In this work, we present our findings that hsa-miR-632 (miR-632) targets the coding region of DNAJB6. Invasive and metastatic breast cancer cells express high levels of miR-632 compared with mammary epithelial cells. Analysis of RNA from breast tumor specimens reveals inverse expression patterns of DNAJB6 transcript and miR-632. In response to exogenous miR-632 expression, DNAJB6 protein levels are downregulated and the resultant cell population shows significantly increased invasive ability. Silencing endogenous miR-632 abrogates invasive ability of breast cancer cells and promotes epithelial like characteristics noted by E-cadherin expression with concomitant decrease in mesenchymal markers such as Zeb2 and Slug. Thus, miR-632 is a potentially important epigenetic regulator of DNAJB6, which contributes to the downregulation of DNAJB6 and plays a supportive role in malignant progression.
Project description:In fibrotic diseases, myofibroblasts derive from a range of cell types including endothelial-to-mesenchymal transition (EndMT). Increasing evidence suggests that miRNAs are key regulators in biological processes but their profile is relatively understudied in EndMT. In human umbilical vein endothelial cells (HUVEC), EndMT was induced by treatment with TGFβ2 and IL1β. A significant decrease in endothelial markers such as VE-cadherin, CD31 and an increase in mesenchymal markers such as fibronectin were observed. In parallel, miRNA profiling showed that miR-126-3p was down-regulated in HUVECs undergoing EndMT and over-expression of miR-126-3p prevented EndMT, maintaining CD31 and repressing fibronectin expression. EndMT was investigated using lineage tracing with transgenic Cdh5-Cre-ERT2; Rosa26R-stop-YFP mice in two established models of fibrosis: cardiac ischaemic injury and kidney ureteric occlusion. In both cardiac and kidney fibrosis, lineage tracing showed a significant subpopulation of endothelial-derived cells expressed mesenchymal markers, indicating they had undergone EndMT. In addition, miR-126-3p was restricted to endothelial cells and down-regulated in murine fibrotic kidney and heart tissue. These findings were confirmed in patient kidney biopsies. MiR-126-3p expression is restricted to endothelial cells and is down-regulated during EndMT. Over-expression of miR-126-3p reduces EndMT, therefore, it could be considered for miRNA-based therapeutics in fibrotic organs.
Project description:Bicuspid aortic valve (BAV) is the most common congenital heart malformation frequently associated with ascending aortic aneurysm (AscAA). Epithelial to mesenchymal transition (EMT) may play a role in BAV-associated AscAA. The aim of the study was to investigate the type of EMT associated with BAV aortopathy using patients with a tricuspid aortic valve (TAV) as a reference. The state of the endothelium was further evaluated. Aortic biopsies were taken from patients undergoing open-heart surgery. Aortic intima/media miRNA and gene expression was analyzed using Affymetrix human transcriptomic array. Histological staining assessed structure, localization, and protein expression. Migration/proliferation was assessed using ORIS migration assay. We show different EMT types associated with BAV and TAV AscAA. Specifically, in BAV-associated aortopathy, EMT genes related to endocardial cushion formation were enriched. Further, BAV vascular smooth muscle cells were less proliferative and migratory. In contrast, TAV aneurysmal aortas displayed a fibrotic EMT phenotype with medial degenerative insults. Further, non-dilated BAV aortas showed a lower miRNA-200c-associated endothelial basement membrane LAMC1 expression and lower CD31 expression, accompanied by increased endothelial permeability indicated by increased albumin infiltration. Embryonic EMT is a characteristic of BAV aortopathy, associated with endothelial instability and vascular permeability of the non-dilated aortic wall. KEY MESSAGES: Embryonic EMT is a feature of BAV-associated aortopathy. Endothelial integrity is compromised in BAV aortas prior to dilatation. Non-dilated BAV ascending aortas are more permeable than aortas of tricuspid aortic valve patients.
Project description:The pathological hallmark lesions in idiopathic pulmonary fibrosis are the fibroblastic foci, in which fibroblasts are thought to be involved in the tissue remodeling, matrix deposition, and cross-talk with alveolar epithelium. Recent evidence indicates that some fibroblasts in fibrosis may be derived from bone marrow progenitors as well as from epithelial cells through epithelial-mesenchymal transition. To evaluate whether endothelial cells could represent an additional source for fibroblasts, bleomycin-induced lung fibrosis was established in Tie2-Cre/CAG-CAT-LacZ double-transgenic mice, in which LacZ was stably expressed in pan-endothelial cells. Combined X-gal staining and immunocytochemical staining for type I collagen and alpha-smooth muscle actin revealed the presence of X-gal-positive cells in lung fibroblast cultures from bleomycin-treated mice. To explore the underlying mechanisms, by which loss of endothelial-specific markers and gain of mesenchymal phenotypes could be involved in microvascular endothelial cells, the effects of activated Ras and TGF-beta on the microvascular endothelial cell line MS1 were analyzed. Combined treatment with activated Ras and TGF-beta caused a significant loss of endothelial-specific markers, while inducing de novo mesenchymal phenotypes. The altered expression of these markers in MS1 cells with activated Ras persisted after withdrawal of TGF-beta in vitro and in vivo. These findings are the first to show that lung capillary endothelial cells could give rise to significant numbers of fibroblasts through an endothelial-mesenchymal transition in bleomycin-induced lung fibrosis model.
Project description:Macroautophagy/autophagy plays a vital role in the homeostasis of diverse cell types. Vascular endothelial cells contribute to vascular health and play a unique role in vascular biology. Here, we demonstrated that autophagy defects in endothelial cells induced IL6 (interleukin 6)-dependent endothelial-to-mesenchymal transition (EndMT) and organ fibrosis with metabolic defects in mice. Inhibition of autophagy, either by a specific inhibitor or small interfering RNA (siRNA) for ATG5 (autophagy related 5), in human microvascular endothelial cells (HMVECs) induced EndMT. The IL6 level was significantly higher in ATG5 siRNA-transfected HMVECs culture medium compared with the control HMVECs culture medium, and neutralization of IL6 by a specific antibody completely inhibited EndMT in ATG5 siRNA-transfected HMVECs. Similar to the in vitro data, endothelial-specific atg5 knockout mice (Atg5 Endo; Cdh5-Cre Atg5 flox/flox mice) displayed both EndMT-associated kidney and heart fibrosis when compared to littermate controls. The plasma level of IL6 was higher in Atg5 Endo compared to that of control mice, and fibrosis was accelerated in Atg5 Endo treated with a HFD; neutralization of IL6 by a specific antibody inhibited EndMT and fibrosis in HFD-fed Atg5 Endo associated with the amelioration of metabolic defects. These results revealed the essential role of autophagy in endothelial cell integrity and revealed that the disruption of endothelial autophagy could lead to significant pathological IL6-dependent EndMT and organ fibrosis. Abbreviations: 3-MA: 3-methyladenine; ATG5: autophagy related 5; EndMT: endothelial-to-mesenchymal transition; HES: hematoxylin and eosin stain; HFD: high-fat diet; HMVECs: human microvascular endothelial cells; IFNG: interferon gamma; IL6: interleukin 6; MTS: Masson's trichrome staining; NFD: normal-fat diet; siRNA: small interfering RNA; SMAD3: SMAD family member 3; TGFB: transforming growth factor β; TNF: tumor necrosis factor; VEGFA: vascular endothelial growth factor A.
Project description:The endothelial-to-mesenchymal transition (EndoMT) is involved in the complex pathogenesis of renal fibrosis. The soluble proteoglycan endothelial cell-specific molecule 1 (ESM1) is significantly upregulated in many tumor cells and cirrhosis-related disease. The role of ESM1 in renal fibrosis is unknown. This study investigates the role of ESM1 in renal fibrosis, using an in vivo unilateral ureteral obstruction (UUO) mouse model of renal fibrosis and in vitro mouse kidney MES 13 cells overexpressing ESM1. We observed that ESM1 overexpression significantly increased the motility and migration of MES 13 cells, independent of cell viability. In ESM1-overexpressing MES 13 cells, we also observed elevated expression of mesenchymal markers (N-cadherin, vimentin, matrix metallopeptidase 9 (MMP9)) and the fibrosis marker ?-smooth muscle actin (?-SMA) and decreased expression of the endothelial marker vascular endothelial cadherin (VE-cadherin) and CD31. In a mouse model of fibrosis induced by unilateral ureter obstruction, we observed time-dependent increases in ESM1, ?-SMA, and vimentin expression and renal interstitial collagen fibers in kidney tissue samples. These results suggest that ESM1 may serve as an EndoMT marker of renal fibrosis progression.
Project description:Emerging evidence has suggested the critical role of endothelial to mesenchymal transition (EndMT) in fibrotic diseases. The present study was designed to examine whether EndMT is involved in arsenic trioxide (As2O3)-induced cardiac fibrosis and to explore the underlying mechanisms. Cardiac dysfunction was observed in rats after exposure to As2O3 for 15 days using echocardiography, and the deposition of collagen was detected by Masson's trichrome staining and electron microscope. EndMT was indicated by the loss of endothelial cell markers (VE-cadherin and CD31) and the acquisition of mesenchymal cell markers (α-SMA and FSP1) determined by RT-PCR at the mRNA level and Western blot and immunofluorescence analysis at the protein level. In the in-vitro experiments, endothelial cells acquired a spindle-shaped morphology accompanying downregulation of the endothelial cell markers and upregulation of the mesenchymal cell markers when exposed to As2O3. As2O3 activated the AKT/GSK-3β/Snail signaling pathway, and blocking this pathway with PI3K inhibitor (LY294002) abolished EndMT in As2O3-treated endothelial cells. Our results highlight that As2O3 is an EndMT-promoting factor during cardiac fibrosis, suggesting that targeting EndMT is beneficial for preventing As2O3-induced cardiac toxicity.
Project description:Idiopathic pulmonary fibrosis (IPF) is a prevalent interstitial lung disease with high mortality. CD38 is a main enzyme for intracellular nicotinamide adenine dinucleotide (NAD+) degradation in mammals. It has been reported that CD38 participated in pulmonary fibrosis through promoting alveolar epithelial cells senescence. However, the roles of endothelial CD38 in pulmonary fibrosis remain unknown. In the present study, we observed that the elevated expression of CD38 was related to endothelial-to-mesenchymal transition (EndMT) of lung tissues in IPF patients and bleomycin (BLM)-induced pulmonary fibrosis mice and also in human umbilical vein endothelial cells (HUVECs) treated with BLM. Micro-computed tomography (MCT) and histopathological staining showed that endothelial cell-specific CD38 knockout (CD38EndKO) remarkably attenuated BLM-induced pulmonary fibrosis. In addition, CD38EndKO significantly inhibited TGFβ-Smad3 pathway-mediated excessive extracellular matrix (ECM), reduced Toll-like receptor4-Myeloid differentiation factor88-Mitogen-activated protein kinases (TLR4-MyD88-MAPK) pathway-mediated endothelial inflammation and suppressed nicotinamide adenine dinucleotide phosphate oxidases1 (NOX1)-mediated oxidative stress. Furthermore, we demonstrated that 3-TYP, a SIRT3-specific inhibitor, markedly reversed the protective effect of HUVECsCD38KD cells and 78 C, a CD38-specific inhibitor, on BLM-induced EndMT in HUVECs. Therefore, we concluded that CD38EndKO significantly ameliorated BLM-induced pulmonary fibrosis through inhibiting ECM, endothelial inflammation and oxidative stress, further alleviating EndMT in mice. Our findings suggest that endothelial CD38 may be a new therapeutic target for the prevention and treatment of pulmonary fibrosis clinically.
Project description:In addition to mesenchymal cells, endothelial cells may contribute to fibrosis through the process of endothelial-to-mesenchymal transition (EndoMT). We investigated whether human intestinal microvascular endothelial cells (HIMEC) undergo EndoMT and contribute to fibrosis in human and experimental inflammatory bowel disease (IBD). HIMEC were exposed to TGF-?1, IL-1?, and TNF-? or supernatants of lamina propria mononuclear cells (LPMC) and evaluated for morphological, phenotypic, and functional changes compatible with EndoMT. Genomic analysis was used to identify transcription factors involved in the transformation process. Evidence of in situ and in vivo EndoMT was sought in inflamed human and murine intestine. The combination of TGF-?1, IL-1? and TNF-?, or activated LPMC supernatants induced morphological and phenotypic changes consistent with EndoMT with a dominant effect by IL-1. These changes persisted after removal of the inducing agents and were accompanied by functional loss of acetylated LDL-uptake and migratory capacity, and acquisition of de novo collagen synthesis capacity. Sp1 appeared to be the main transcriptional regulator of EndoMT. EndoMT was detected in microvessels of inflammatory bowel disease (IBD) mucosa and experimental colonic fibrosis of Tie2-green fluorescent protein (GFP) reporter-expressing mice. In conclusion, chronic inflammation induces transdifferentiation of intestinal mucosal microvascular cells into mesenchymal cells, suggesting that the intestinal microvasculature contributes to IBD-associated fibrosis through the novel process of EndoMT.
Project description:Rationale: Cardiac fibrosis is an integral constituent of every form of chronic heart disease, and persistence of fibrosis reduces tissue compliance and accelerates the progression to heart failure. Relaxin-2 is a human hormone, which has various physiological functions such as mediating renal vasodilation in pregnancy. Its recombinant form Serelaxin has recently been tested in clinical trials as a therapy for acute heart failure but did not meet its primary endpoints. The aim of this study is to examine whether Serelaxin has an anti-fibrotic effect in the heart and therefore could be beneficial in chronic heart failure. Methods: We utilized two different cardiac fibrosis mouse models (ascending aortic constriction (AAC) and Angiotensin II (ATII) administration via osmotic minipumps) to assess the anti-fibrotic potential of Serelaxin. Histological analysis, immunofluorescence staining and molecular analysis were performed to assess the fibrosis level and indicate endothelial cells which are undergoing EndMT. In vitro TGFβ1-induced endothelial-to-mesenchymal transition (EndMT) assays were performed in human coronary artery endothelial cells and mouse cardiac endothelial cells (MCECs) and were examined using molecular methods. Chromatin immunoprecipitation-qPCR assay was utilized to identify the Serelaxin effect on chromatin remodeling in the Rxfp1 promoter region in MCECs. Results: Our results demonstrate a significant and dose-dependent anti-fibrotic effect of Serelaxin in the heart in both models. We further show that Serelaxin mediates this effect, at least in part, through inhibition of EndMT through the endothelial Relaxin family peptide receptor 1 (RXFP1). We further demonstrate that Serelaxin administration is able to increase its own receptor expression (RXFP1) through epigenetic regulation in form of histone modifications by attenuating TGFβ-pSMAD2/3 signaling in endothelial cells. Conclusions: This study is the first to identify that Serelaxin increases the expression of its own receptor RXFP1 and that this mediates the inhibition of EndMT and cardiac fibrosis, suggesting that Serelaxin may have a beneficial effect as anti-fibrotic therapy in chronic heart failure.