Project description:Objective: Vascular smooth muscle cells (VSMCs) undergo the phenotypic changes from contractile to synthetic state during vascular remodeling after ischemia. SIRT1 protects against stress-induced vascular remodeling via maintaining VSMC differentiated phenotype. However, the effect of smooth muscle SIRT1 on the functions of endothelial cells (ECs) has not been well clarified. Here, we explored the role of smooth muscle SIRT1 in endothelial angiogenesis after ischemia and the underlying mechanisms. Methods: We performed a femoral artery ligation model using VSMC specific human SIRT1 transgenic (SIRT1-Tg) and knockout (KO) mice. Angiogenesis was assessed in in vivo by quantification of the total number of capillaries, wound healing and matrigel plug assays, and in vitro ECs by tube formation, proliferation and migration assays. The interaction of HIF1? with circRNA was examined by using RNA immunoprecipitation, RNA pull-down and in situ hybridization assays. Results: The blood flow recovery was significantly attenuated in SIRT1-Tg mice, and markedly improved in SIRT1-Tg mice treated with SIRT1 inhibitor EX527 and in SIRT1-KO mice. The density of capillaries significantly decreased in the ischemic gastrocnemius of SIRT1-Tg mice compared with SIRT1-KO and WT mice, with reduced expression of VEGFA, which resulted in decreased number of arterioles. We identified that the phenotypic switching of SIRT1-Tg VSMCs was attenuated in response to hypoxia, with high levels of contractile proteins and reduced expression of the synthetic markers and NG2, compared with SIRT1-KO and WT VSMCs. Mechanistically, SIRT1-Tg VSMCs inhibited endothelial angiogenic activity induced by hypoxia via the exosome cZFP609. The cZFP609 was delivered into ECs, and detained HIF1? in the cytoplasm via its interaction with HIF1?, thereby inhibiting VEGFA expression and endothelial angiogenic functions. Meantime, the high cZFP609 expression was observed in the plasma of the patients with atherosclerotic or diabetic lower extremity peripheral artery disease, associated with reduced ankle-brachial index. Knockdown of cZFP609 improved blood flow recovery after hindlimb ischemia in SIRT1-Tg mice. Conclusions: Our findings demonstrate that SIRT1 may impair the plasticity of VSMCs. cZFP609 mediates VSMCs to reprogram endothelial functions, and serves as a valuable indicator to assess the prognosis and clinical outcomes of ischemic diseases.

Project description:Thiele2013 - Smooth muscle smooth muscle cells The model of smooth muscle smooth muscle cells metabolism is derived from the community-driven global reconstruction of human metabolism (version 2.02, MODEL1109130000 ). This model is described in the article: A community-driven global reconstruction of human metabolism. Thiele I, et al . Nature Biotechnology Abstract: Multiple models of human metabolism have been reconstructed, but each represents only a subset of our knowledge. Here we describe Recon 2, a community-driven, consensus 'metabolic reconstruction', which is the most comprehensive representation of human metabolism that is applicable to computational modeling. Compared with its predecessors, the reconstruction has improved topological and functional features, including ~2x more reactions and ~1.7x more unique metabolites. Using Recon 2 we predicted changes in metabolite biomarkers for 49 inborn errors of metabolism with 77% accuracy when compared to experimental data. Mapping metabolomic data and drug information onto Recon 2 demonstrates its potential for integrating and analyzing diverse data types. Using protein expression data, we automatically generated a compendium of 65 cell type-specific models, providing a basis for manual curation or investigation of cell-specific metabolic properties. Recon 2 will facilitate many future biomedical studies and is freely available at http://humanmetabolism.org/. This model is hosted on BioModels Database and identified by: MODEL1310110025 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Project description:Derivation of induced smooth muscle cells (iSMC) through direct transdifferentiation of a convenient and expandable primary cell source would open a wide range of prospects for their use in tissue engineering, drug testing, and disease modeling. Hypothesizing that MYOCD as a master regulator of smooth muscle gene expression would facilitate the generation of iSMC, we studied the conversion of human endothelial progenitor cells (EPC) into iSMC through the induced expression of by over-expression of MYOCD. A significant cytoskeletal rearrangement of the EPC resembling that of mesenchymal cells occurred within 3 days post initiation of MYOCD expression. This transition was associated with a downregulation of endothelial cell surface markers (CD31, CD105) as determined by flow cytometry. By day 7, iSMC derivation was evident with a significant upregulation of smooth muscle markers ACTA2, MYH11, TAGLN, and downregulation of CD31 and CDH5 as determined by gene expression analysis. Immunofluorescence revealed expression of MYH11 and ACTA2 and absence of endothelial markers VWF and CD31. By two weeks, microarray gene expression analysis demonstrated a significant similarity between iSMC and umbilical artery SMC (UASMC). The iSMC continued to develop toward the SMC lineage after four weeks of MYOCD induced expression. Microarray gene expression analysis showed an upregulation of molecular pathways associated with smooth muscle contraction and cytoskeletal reorganization in iSMC. Calcium transients were detected in iSMC when stimulated with phenylephrine but not in EPC. Contractility of iSMC was also higher than that of EPC as determined by traction force microscopy. Tissue-engineered blood vessels constructed using iSMC showed functionality with respect to flow- and drug- mediated vasodilation and vasoconstriction. We used microarrays to detail the global programme of gene expression underlying the transdifferentiation of endothelial progenitor cells into smooth muscle cells via the transient induced expression of the transcriptional co factor MYOCD

Project description:Arterial smooth muscle cells (ASMCs) undergo phenotypic changes during development and pathological processes in vivo and during cell culture in vitro. Our previous studies demonstrated that retrovirally-mediated expression of the versican V3 splice variant (V3) that lacks glycosaminoglycan chains by ASMCs retards cell proliferation and migration in vitro and reduces neointimal thickening, macrophage and lipid accumulation in animal models of vascular injury and atherosclerosis. However, the molecular pathways induced by V3 expression that are responsible for these changes are not yet clear. In the present study, we employed a microarray approach to examine how expression of V3 induced changes in gene expression and the molecular pathways in ASMCs. We found that forced expression of V3 by ASMCs affected expression of 521 genes by more than 1.5 fold. Gene ontology (GO) analysis shows that components of extracellular matrix were the most significantly affected by V3 expression, indicating that V3 expression elicits profound remodeling of extracellular matrix. In addition, genes regulating the formation of the cytoskeleton which also serve as markers of contractile smooth muscle cells were significantly upregulated. On the other hand, components of the complement system, chemokines, chemokine receptors, and transcription factors crucial for regulating inflammatory processes were among the genes most downregulated. Consistently, we found that the level of myocardin, a key transcription factor promoting contractile ASMC phenotype, was greatly increased while proinflammatory transcription factors NFkappaB1 and C/EBPβ were significantly attenuated in V3-expressing SMCs. Such results indicate that V3 expression reprograms ASMC into differentiated and anti-inflammatory phenotypes. Overall, these findings demonstrate that expression of V3 reprograms ASMCs promoting anti-inflammatory and differentiated smooth muscle cell phenotypes potentially by altering cell-ECM interaction and focal adhesion signaling pathways. Fischer rat ASMCs were transduced with either a retroviral vector expressing the Versican V3 splice variant (LV3SN) or an empty control vector (LXSN) in three independent experiments. In the first experiment, V3 and control transductions were performed with four technical replicates. In the subsequent two experiments, individual transductions were done for the V3 or control treatments. For data analysis, the technical replicates from the first experiment were averaged, and then data from the three experiments was evaluated in a paired manner.

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A miRNA Cassette Reprograms Smooth Muscle Cells into Endothelial Cells

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