Project description:TLDA miRNA profiling on purified rat cardiomyocytes (Myo) (Ctl) and myocyte-derived progenitor cells (MDCs) demonstrated significant dedifferentiation of myocytes and identity of stemness, cell cycle progression and proliferation in MDCs after continuous culture in mitogen-rich medium for about 2 weeks. Total RNA was extracted from 3 batches of myocytes or MDCs; 100ug each was subjected to TLDA microRNA profiling after preamplification using ABI's kit. Cardiomyocyte (Myo, Ctl) was used as calibrator sample.
Project description:Rationale: Neonatal mice have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. The transcriptional changes that underpin mammalian cardiac regeneration have not been fully characterized at the molecular level. Objective: The objectives of our study were to determine if myocytes revert the transcriptional phenotype to a less differentiated state during regeneration and to systematically interrogate the transcriptional data to identify and validate potential regulators of this process. Methods and Results: We derived a core transcriptional signature of injury-induced cardiac myocyte regeneration in mouse by comparing global transcriptional programs in a dynamic model of in vitro and in vivo cardiac myocyte differentiation, in vitro cardiac myocyte explant model, as well as a neonatal heart resection model. The regenerating mouse heart revealed a transcriptional reversion of cardiac myocyte differentiation processes including reactivation of latent developmental programs similar to those observed during de-stabilization of a mature cardiac myocyte phenotype in the explant model. We identified potential upstream regulators of the core network, including interleukin 13 (IL13), which induced cardiac myocyte cell cycle entry and STAT6/STAT3 signaling in vitro. We demonstrate that STAT3/periostin and STAT6 signaling are critical mediators of IL13 signaling in cardiac myocytes. These downstream signaling molecules are also modulated in the regenerating mouse heart. Conclusions: Our work reveals new insights into the transcriptional regulation of mammalian cardiac regeneration and provides the founding circuitry for identifying potential regulators for stimulating heart regeneration. Comparison of transcriptional programs of primary myocardial tissues sampled from neonatal mice and murine hearts undergoing post-injury regeneration, along with in vitro ESC-differentiated cardiomyocytes
Project description:Rationale: Neonatal mice have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. The transcriptional changes that underpin mammalian cardiac regeneration have not been fully characterized at the molecular level. Objective: The objectives of our study were to determine if myocytes revert the transcriptional phenotype to a less differentiated state during regeneration and to systematically interrogate the transcriptional data to identify and validate potential regulators of this process. Methods and Results: We derived a core transcriptional signature of injury-induced cardiac myocyte regeneration in mouse by comparing global transcriptional programs in a dynamic model of in vitro and in vivo cardiac myocyte differentiation, in vitro cardiac myocyte explant model, as well as a neonatal heart resection model. The regenerating mouse heart revealed a transcriptional reversion of cardiac myocyte differentiation processes including reactivation of latent developmental programs similar to those observed during de-stabilization of a mature cardiac myocyte phenotype in the explant model. We identified potential upstream regulators of the core network, including interleukin 13 (IL13), which induced cardiac myocyte cell cycle entry and STAT6/STAT3 signaling in vitro. We demonstrate that STAT3/periostin and STAT6 signaling are critical mediators of IL13 signaling in cardiac myocytes. These downstream signaling molecules are also modulated in the regenerating mouse heart. Conclusions: Our work reveals new insights into the transcriptional regulation of mammalian cardiac regeneration and provides the founding circuitry for identifying potential regulators for stimulating heart regeneration.
Project description:TLDA miRNA profiling on purified rat cardiomyocytes (Myo) (Ctl) and myocyte-derived progenitor cells (MDCs) demonstrated significant dedifferentiation of myocytes and identity of stemness, cell cycle progression and proliferation in MDCs after continuous culture in mitogen-rich medium for about 2 weeks.
Project description:We were interested in identifying proteins that are regulated in response to the extracellular matrix molecule, fibronectin, in dermal fibroblasts. To determine proteins regulated by exposure to fibronectin, primary murine dermal fibroblasts were cultured on tissue culture plastic or on tissue culture plates coated with a thin layer of fibronectin (2 μg/cm2). Fibroblasts were seeded at 35,000 cells/10 cm2 and were harvested 48 hours later. Cell pellets from these fibroblasts were shipped to Kinexus Bioinformatics Corp. (Vancouver, B.C.) where they were lysed and analyzed using the Kinex TM Antibody Microarray (KAM 1.2), which contains 800 (500 pan-specific and 300 phosphorylation site-specific) antibodies. This enabled us to identify candidate proteins regulated by exposure to fibronectin.
Project description:The goal of the study was to identify on a genome-wide scale RNAs that are enriched at the leading edge of migrating cells. For this, we employed a fractionation method in which cells are plated on a microporous filter whose bottom side only is coated with fibronectin. The cells thus polarize and extend pseudopodial protrusions towards the bottom surface. These protruding pseudopodia can then be physically isolated from the bottom surface of the filter and their contents compared with the remaining cell bodies, which are isolated from the upper surface of the filter. Keywords: comparative RNA distribution
Project description:The mammalian heart is composed of a variety types of cells that can be roughly categorized into cardiomyocytes and non-myocytes. Instead of being bystanders of cardiac function, cardiac non-myocytes provide critical structural, mechanical and electrophysiological support to the working myocardium. However, the precise cellular identity and molecular features of the non-myocytes at single cell level remain elusive. Depiction of epigenetic landscape with transcriptomic signatures using the latest single cell multi-omics has the potential to unravel the molecular programs of cardiac non-myocytes underlying their cellular diversity. To characterize the molecular and cellular features of cardiac non-myocytes populations in the adult murine heart at single cell level. We applied single cell Assay for Transposase Aaccessible Chromatin using sequencing (scATAC-seq) in combination with high-throughput single cell RNA-seq (scRNA-seq) to map the epigenetic landscape and gene expression program of cardiac non-myocytes from adult murine heart. Through integrated dual-omics data analysis, we categorize the cardiac non-myocytes into 4 defined populations including endothelial cells, fibroblast, pericytes and immune cells with distinct chromatin accessibility patterns. Cis- and trans-regulatory factors for each cell type were identified. In particular, unbiased sub-clustering and functional annotation of the cardiac fibroblast (FB), indicated the heterogeneity and functionality of FB subtypes associated with cellular response, cytoskeleton organization and immune regulation. We further validated the expression and function of novel markers in major FB sub-populations and experimentally determined the distribution of the FB sub-populations in healthy and injured murine heart. In summary, we comprehensively characterized the non-myocyte cellular identity at the single-cell level and defined FB subpopulations by their functional states.
Project description:The mammalian heart is composed of a variety types of cells that can be roughly categorized into cardiomyocytes and non-myocytes. Instead of being bystanders of cardiac function, cardiac non-myocytes provide critical structural, mechanical and electrophysiological support to the working myocardium. However, the precise cellular identity and molecular features of the non-myocytes at single cell level remain elusive. Depiction of epigenetic landscape with transcriptomic signatures using the latest single cell multi-omics has the potential to unravel the molecular programs of cardiac non-myocytes underlying their cellular diversity. To characterize the molecular and cellular features of cardiac non-myocytes populations in the adult murine heart at single cell level. We applied single cell Assay for Transposase Aaccessible Chromatin using sequencing (scATAC-seq) in combination with high-throughput single cell RNA-seq (scRNA-seq) to map the epigenetic landscape and gene expression program of cardiac non-myocytes from adult murine heart. Through integrated dual-omics data analysis, we categorize the cardiac non-myocytes into 4 defined populations including endothelial cells, fibroblast, pericytes and immune cells with distinct chromatin accessibility patterns. Cis- and trans-regulatory factors for each cell type were identified. In particular, unbiased sub-clustering and functional annotation of the cardiac fibroblast (FB), indicated the heterogeneity and functionality of FB subtypes associated with cellular response, cytoskeleton organization and immune regulation. We further validated the expression and function of novel markers in major FB sub-populations and experimentally determined the distribution of the FB sub-populations in healthy and injured murine heart. In summary, we comprehensively characterized the non-myocyte cellular identity at the single-cell level and defined FB subpopulations by their functional states.
Project description:Directing differentiation of human embryonic stem cells (hESC) into specific cell types using an easy and reproducible protocol is a perquisite for the clinical use of hESC in regenerative medicine protocols. Here, we report the generation of mesodermal cells with differentiation potential to myocytes, osteoblasts, chondrocytes and adipocytes. We demonstrate that during hESC differentiation as embryoid bodies (EB), inhibition of TGF-b/Activin/Nodal signaling using SB-431542 (SB) markedly up-regulated paraxial mesodermal markers (TBX6, TBX5), early myogenic transcriptional factors (Myf5, Pax7) as well as myocyte committed markers (NCAM, CD34, Desmin, MHC (fast), alpha-smooth muscle actin, Nkx2.5, cTNT). Establishing EB outgrowth cultures (SB-OG) in the presence of SB (1 uM) led to further enrichment of cells expressing markers for myocyte progenitor cell: CD34+ (33%), NCAM+ (CD56) (73%), PAX7 (25%) and mature myocyte proteins (MYOD1, tropomyocin, fast MHC an; d SERCA1). Further analysis using DNA microarray revealed differential up-regulation of 117 genes (>2-fold compared to control cells) annotated to myogenic development and function. During ex vivo culture, contracting myocytes were observed (80% of the population) and the cells formed myofibres when implanted intramuscularly in vivo. Furthermore, in the presence of fetal bovine serum (10% FBS), SB-OG cells developed morphologically and phenotypically into a homogeneous stromal (mesenchymal) stem cell (MSC)-like population expressing characteristic MSC CD markers: CD44 (100%), CD73 (98%), CD146 (96%) and CD166 (88%). They were karyotypically normal and were able to differentiate ex vivo and in vivo into osteoblasts, adipocytes and chondrocytes. Experiment Overall Design: Human ESCs were differentiated as EBs for 10 days, where after EBs were plated onto fibronectin coated petri dishes. At confluency the outgrowth culture was passaged, at passage 5 3 samples were taken from both control-OG and SB-OG. the samples were mixed and frozen.