Project description:Differentiated Vascular Smooth Muscle Cells (VSMCs) express a unique network of splice isoforms (smooth muscle specific alternative splicing - SM-AS) in functionally critical genes including those comprising the contractile machinery. We previously described RNA Binding Protein Multiple Splicing (RBPMS) as a potent driver of contractile, aortic tissue like SM-AS in VSMCs using rodent models. What is unknown is how RBPMS affects VSMC phenotype and behaviour. Here, we use human embryonic stem cell-derived VSMCs (hES-VSMCs) to dissect the role of RBPMS in SM-AS in human cells and determine the impact on VSMC phenotypic properties. hES-VSMCs are inherently immature and display only partially differentiated SM-AS patterns while RBPMS levels are undetectable endogenously. Hence, we used an over-expression system and found that RBPMS induces SM-AS patterns in hES-VSMCs akin to the contractile tissue VSMC splicing patterns in multiple events. We present in silico and experimental findings that support RBPMS’ splicing activity as mediated through direct binding and via functional cooperativity with splicing factor RBFOX2 on a significant subset of targets. Finally, we demonstrate that RBPMS can alter the motility and the proliferative properties of hES-VSMCs to mimic a more differentiated state. Overall, this study emphasizes a critical splicing regulatory role for RBPMS in human VSMCs and provides evidence of phenotypic modulation by RBPMS.
Project description:Investigation of RBPMS role in post-transcriptional control of mRNAs in rat PAC1 pulmonary artery smooth muscle cells (SMCs). PolyA mRNA-Seq was carried out after RBPMS knockdown in differentiated PAC1 cells and after inducible RBPMS-A overexpression in dedifferentiated (proliferative) PAC1 cells.
Project description:This experiment is part of the FunGenES project (FunGenES - Functional Genomics in Embryonic Stem Cells partially funded by the 6th Framework Programme of the EuropeanUnion, http://www.fungenes.org). The experiment was conducted at University of Cologne, Cologne, Germany. Goal of the experiment is a complete transcriptome profiling of contractile smooth muscle cells (SMCs) differentiated from embryonic stem cells which is crucial for the characterization of smooth muscle gene expression signatures and will contribute to defining biological and physiological processes in these cells. We have generated a transgenic embryonic stem cell line expressing both the puromycin acetyl transferase and enhanced green fluorescent protein cassettes under the control of the Acta2 promoter.This experiment allows the identification of specific biological and physiological processes in the contractile phenotype SMCs and will contribute to the understanding of these processes in early SMCs derived from embryonic stem cells.
Project description:Smooth muscle differentiation has been proposed to sculpt airway epithelial branches in mammalian lungs. Serum response factor (SRF) acts with its cofactor myocardin to promote the expression of contractile smooth muscle markers. However, smooth muscle cells exhibit a variety of phenotypes beyond contractile that are independent of SRF-myocardin-induced transcription. To determine whether airway smooth muscle exhibits phenotypic plasticity during embryonic development, we deleted Srf from the pulmonary mesenchyme. Srf-mutant lungs branch normally, and the mesenchyme exhibits normal cytoskeletal features and patterning. scRNA-seq revealed an Srf-null smooth muscle cluster wrapping the airways of mutant lungs that lacks contractile smooth muscle markers but retains many features of control smooth muscle. Srf-null airway smooth muscle exhibits a synthetic phenotype, compared to the contractile phenotype of wildtype airway smooth muscle. Our findings reveal plasticity in mesenchymal differentiation during lung development and demonstrate that a synthetic smooth muscle layer is sufficient for airway branching morphogenesis.
Project description:This project contains the proteomics data for the manuscript "Novel role of LRP1 in the regulation of smooth muscle contractile function by regulating cytoskeletal dynamics and Ca2+ signaling." by Au et al.
Project description:Altered gastrointestinal (GI) motility is associated with significant morbidity and mortality. Here, we aimed at delineating the functional role of Carmn (Cardiac mesoderm enhancer-associated noncoding RNA), a SMC-specific lncRNA, in GI motility. In this study, we observed that Carmn global knockout (gKO) or inducible smooth muscle cell-specific KO (iKO) mice exhibited premature lethality owing to colonic pseudo-obstruction, characterized by severe distension of the cecum and colon. Bulk RNA-seq and snRNA-seq of colonic muscularis showed that Carmn deficiency impairs the contraction of the colonic muscularis and disrupts the colon homeostasis, which closely related with the down-regulation of the genes maintain the SMC contraction, especially the Mylk. Overall, our data suggest that Carmn is indispensable for maintaining GI contractile function.
Project description:Lung smooth muscle cells are including bronchiolar and vascular smooth muscle cells. In order to get adult lung smooth muscle cells, we use transgenic mouse line with smooth muscle actin creERT2, which is a transgenic cre recombinase in Acta2 (contractile smooth muscle cell gene). This mouse line also contains a CAG promoter-driven red fluorescent protein variant (tdTomato) - all inserted into the ROSA26 locus. This mouse line express robust tdTomato fluorescence following cre-mediated recombination after Tamoxifen injection.
Project description:Background: Modulation of mRNA splicing acts as an important layer of gene regulation, in addition to transcriptional regulation and epigenetic modifications. RNA binding proteins (RBPs) play essential roles in mediating RNA splicing and are key regulators of heart development and function. Our previous studies demonstrated that RBPMS (RNA-binding protein with multiple splicing) regulates cardiac development through modulating mRNA splicing during embryogenesis. Here we explored the postnatal function of RBPMS in the heart. Methods: We ablated Rbpms in the heart by generating a cardiac-specific knockout mouse line (Myh6-Cre, Rbpmsfl/fl), and evaluated its cardiac functions by histology, echocardiography, and gene expression. Paired-end RNA sequencing and RT-PCR were performed to identify and validate splicing targets of RBPMS in adult mouse hearts. Proximity-dependent Biotin Identification (BioID) assay and mass spectrometry analysis were performed to identify RBPMS binding partners. We also measured contractility and calcium fluxes in isolated mouse cardiomyocytes, and contractile forces of cardiac papillary muscle. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) were also used as a model to explore the influence of RBPMS on contractility of human cardiomyocytes. Results: he absence of Rbpms in the heart led to dilated cardiomyopathy (DCM) and heart failure, causing early death in mice. Mice with cardiac-specific knockout of Rbpms showed myocardium noncompaction with reduced cardiomyocyte number at the neonatal stage and developed DCM with pervasive myocardial fibrosis in adulthood. We found that RBPMS mediates a largely distinct RNA splicing profile in adult mouse hearts compared to neonatal hearts, indicating a stage-specific modulation of alternative RNA splicing by RBPMS. In adult hearts, RBPMS mainly influenced alternative splicing of genes associated with sarcomere structures and cardiomyocyte contraction, such as Ttn, Pdlim5 and Nexn, to generate new protein isoforms. In neonatal hearts, RBPMS influenced the splicing of cytoskeletal genes. RBMPS was associated with spliceosome factors and other RNA binding proteins that play important roles in the heart, such as RBM20 and GATA4. Importantly, we found that the absence of Rbpms caused severe cardiomyocyte contractile defects and reduced calcium sensitivity in both mouse and hiPSC-CMs. Our results demonstrated that Rbpms is crucial for postnatal cardiac function and cardiomyocyte contractility by regulating RNA alternative splicing. Conclusions: Loss of Rbpms in the heart causes reduced cardiomyocyte number and impaired cardiomyocyte contraction, leading to DCM and heart failure.