Mesp1 Acts as a Master Regulator of Multipotent Cardiovascular Progenitor Specification

Abstract

During embryonic development, multipotent cardiovascular progenitor cells are specified from early mesoderm. Using mouse ESCs in which gene expression can be temporally regulated, we have found that transient expression of Mesp1 dramatically accelerates and enhances multipotent cardiovascular progenitor specification through an intrinsic and cell autonomous mechanism. Genome-wide transcriptional analysis indicates that Mesp1 rapidly activates and represses a discrete set of genes, and chromatin immunoprecipitation shows that Mesp1 directly binds to regulatory DNA sequences located in the promoter of many key genes in the core cardiac transcriptional machinery, resulting in their rapid upregulation. Mesp1 also directly represses the expression of key genes regulating other early mesoderm and endoderm cell fates. Our results demonstrate that Mesp1 acts as a key regulatory switch during cardiovascular specification, residing at the top of the hierarchy of the gene network responsible for cardiovascular cell-fate determination.

Eomesodermin induces Mesp1 expression and cardiac differentiation from embryonic stem cells in the absence of Activin

“…RNA isolation and qRT-PCR. RNA extraction, DNAse treatment and RT-PCR were performed as previously described [25,30]. …”

“…Primary antibodies used were the following: Mouse anti-cardiac isoform of TroponinT Ab1 (1/100; NeoMarkers), Rabbit anti-b-tubulin III (1/2,000; Covance), Goat anti-Sox17 (1/1,000; R&D), Mouse anti-c-Myc (1/1,000; Roche), Mouse anti-Smooth muscle actin (1/200; Sigma), Rabbit anti-Pax6 (1/1,000; Covance), Rat anti-CD144 (VE-cadherin; 1/100; BD Biosciences) and Mouse anti-Flag (M2; 1/500; Sigma). For flow cytometry, stainings against cTnT (Ab1-NeoMarkers), Flk1 (Vegfr2; Avas12a1; eBioscience), Pdgfra (APA5; eBioscience), Cxcr4 (2B11; eBioscience), Epcam (G8.8; Biolegend) and CD31 (MEC13.3; BD Biosciences) were performed as described previously [25,27]. Mice.…”

“…Here we investigated the role of Eomes in early cell fate decisions during mouse ESC differentiation, and found that in the absence of extrinsic signals, Eomes promoted the formation of cardiac mesoderm by stimulating the expression of Mesp1, a transcription factor known to have a key role in the specification of cardiovascular mesoderm [24][25][26][27][28]. High levels of Activin decreased the ability of Eomes to stimulate Mesp1 expression, and instead led to the induction of endodermal fate.…”

Embryonic stem cell application in drug discovery

“…During the early stage of development, differentiationrelated gene expression or transcriptomics can be regulated, and a genome-wide transcriptional analysis has been used as a powerful assay [32,33,49] . For example, genome-wide transcriptional analysis has shown more than just the effects of Mesp1 dramatically accelerates and enhances multipotent cardiovascular progenitor specification through an intrinsic and cellautonomous mechanism.…”

“…This system, which is modeled as a network of regulatory circuits that direct multiple steps of gene expression and mediate spatiotemporal control of a cell's proteome, can determine both cellular phenotype and plasticity [21,27,39,49,58,59] . Commitment to developmental lineages has been considered to be a stepwise process.…”