Project description:Identifying lineage-specific markers is pivotal for understanding developmental processes and developing cell therapies. Here, we report a new cardiomyogenic cell surface marker latrophilin-2 (Lphn2), an adhesion G protein-coupled receptor. When mouse and human pluripotent stem cells (PSCs) were stimulated with BMP4, Activin A, and bFGF, they differentiated into cardiac lineage cells. Lphn2 was selectively expressed on cardiac progenitor cells (CPCs) and cardiomyocytes (CMCs) during the differentiation of mouse PSCs, and cell sorting with an anti-Lphn2 antibody promoted the isolation of populations highly enriched in CPCs and CMCs. Lphn2 knock-down or knock-out PSCs did not express cardiac genes. To investigate the molecular mechanism underlying the induction of cardiac differentiation by Lphn2, we used the Phospho Explorer Antibody Array, which encompasses nearly all known signaling pathways. Lphn2-dependent phosphorylation was strongest for cyclin-dependent kinase 5 (CDK5) at Tyr15. We identified CDK5, Src, and P38MAPK as key downstream molecules of Lphn2. These findings provide a valuable tool for isolating cardiomyogenic progenitors and CMCs from PSCs and shed light on the still-unknown mechanisms of cardiac differentiation.
Project description:TMEM88 is indispensable for heart development and acts in the pre-cardiac mesoderm to specify lineage commitment of the cardiovascular progenitor cell through inhibition of Wnt signaling. 2 different lentiviruses expression shRNA targeting different domains of the TMEM88 locus were transduced into undifferentiated hES cells. Cells were puromycin selected then differentiated along the cardiac lineage. Total RNA was taken at day 5 of differentiation when the cardiovascular progenitor cell arises. 1 sample for each shRNA and 2 samples for control shRNA were analyzed by array
Project description:TMEM88 is indispensable for heart development and acts in the pre-cardiac mesoderm to specify lineage commitment of the cardiovascular progenitor cell through inhibition of Wnt signaling.
Project description:In vitro cardiac differentiation of human ESCs recapitulates in vivo embryonic heart development, and thus, serves as an excellent tool to investigate human cardiac development. Identification of molecular signatures during cardiac differentiation of human ESCs is instrumental for advancing our understanding of human cardiogenesis. We, as well as others have improved cardiac differentiation protocols significantly in recent years; however, detailed molecular mechanisms involved in cardiac lineage commitment have not yet been clearly defined. Based on this, we tried to identify the cellular hierarchies and molecular signatures of each of the in vitro human ESC-differentiating cardiac cell lineages through the well-established cardiac differentiatio protocol by Wnt signaling modulation and the FACS-sorted population RNA-seq analyses.
Project description:A major component of the cardiac stress response is the simultaneous activation of several gene regulatory networks. Interestingly, the transcriptional regulator steroid receptor coactivator-2, SRC-2 is often decreased during cardiac failure in humans. We postulated that SRC-2 suppression plays a mechanistic role in the stress response and that SRC-2 activity is an important regulator of the adult heart gene expression profile. Genome-wide microarray analysis, confirmed with targeted gene expression analyses revealed that genetic ablation of SRC-2 activates the “fetal gene program” in adult mice as manifested by shifts in expression of a) metabolic and b) sarcomeric genes, as well as associated modulating transcription factors. While these gene expression changes were not accompanied by changes in left ventricular weight or cardiac function, imposition of transverse aortic constriction (TAC) predisposed SRC-2 knockout (KO) mice to stress-induced cardiac dysfunction. In addition, SRC-2 KO mice lacked the normal ventricular hypertrophic response as indicated through heart weight, left ventricular wall thickness, and blunted molecular signaling known to activate hypertrophy. Our results indicate that SRC-2 is involved in maintenance of the steady-state adult heart transcriptional profile, with its ablation inducing transcriptional changes that mimic a stressed heart. These results further suggest that SRC-2 deletion interferes with the timing and integration needed to respond efficiently to stress through disruption of metabolic and sarcomeric gene expression and hypertrophic signaling, the three key stress responsive pathways.
Project description:Purpose: Long non-coding RNAs (lncRNAs) display development-specific gene expression patterns, yet we know little about their precise roles in lineage commitment. Here, we discover a novel mammalian heart-associated lncRNA, AK143260, necessary for cardiac lineage specification. Methods: Gene expression profiles of mouse ESCs and differentiated organs were analyzed for master regulators of lineage commitment. The AK143260 transcript was shown to be strongly expressed in mESCs and in cells undergoing cardiac differentiation. Its role in cardiac differentiation was examined using depletion and in vitro differentiation systems, with morphological and gene expression profiling at different time-points. Results: mESCs depleted of AK143260, named Braveheart, fail to differentiate into cardiomyocytes and to activate a core cardiac gene regulatory network including key transcription factors driving cardiogenesis. We show that Braveheart functions upstream of MesP1 (mesoderm posterior 1), a transcription factor critical for specification of the earliest known multi-potent cardiovascular progenitor and in promoting epithelial-mesenchymal transition (EMT). Consistent with this, Braveheart depletion leads to morphological defects and loss of cardiogenic potential in a defined in vitro cardiomyocyte differentiation system. Furthermore, Braveheart is necessary to maintain myocardial gene expression and myofibril organization in neonatal cardiomyocytes. Conclusions: These findings reveal that Braveheart is an important regulator of cardiac commitment and implicate lncRNAs as potential therapeutic targets for cardiac disease and regeneration. Gene expression profiles from control and Bravheart-depleted mESCs were obtained by RNA-Seq on an Illumina HiSeq2000 instruments at Days 0,3,6 and 9. Gene expression profiles from mESCs, MEFs, partially reprogrammed MEFs and miPS cells were obtained by RNA-Seq on Illumina GAII/GAIIx instruments.
Project description:The stepwise conversion of multipotent precursors into committed T-cell progenitors depends on several transcriptional regulators, but the interplay between these factors is still obscure. This is particularly true in human since the core early Notch signalling pathway also supports NK cell development and requires tight regulation for efficient T-lineage commitment and differentiation. Here, we show that GATA3, in contrast to TCF1, induces T-lineage commitment following NOTCH1-induced T-lineage specification through direct regulation of at least 3 distinct processes: repression of NK-cell fate, activation of T-lineage genes to promote further differentiation, and downmodulation of Notch signalling activity. GATA3-mediated repression of the NOTCH1 target gene DTX1 hereby is essential to induce T-lineage commitment at the expense of NK cell differentiation. Thus, human T-lineage commitment is dependent on the precise collaboration of several transcriptional regulators that integrate through both positive and negative regulatory loops. ChIP-sequencing data was generated for GATA3 in human thymocytes
Project description:Background: Gq-coupled G protein-coupled receptors (GPCR) mediate the actions of a variety of messengers that are key regulators of cardiovascular function. Enhanced Gaq-mediated signaling plays an important role in cardiac hypertrophy and in the transition to heart failure. We have recently described that Gaq acts as an adaptor protein that facilitates PKCz-mediated activation of ERK5 in epithelial cells. Since the ERK5 cascade is known to be involved in cardiac hypertrophy, we have investigated the potential relevance of this pathway in Gq-dependent signaling in cardiac cells. Methodology/Principal Findings: We have explored the mechanisms involved in Gq-coupled GPCR-mediated stimulation of the ERK5 pathway and its functional consequences in cardiac hypertrophy using both cultured cardiac cells and an animal model of angiotensin- dependent induction of cardiac hypertrophy in wild-type and PKCz knockout mice. We find that PKC? is required for the activation of the ERK5 pathway by Gq-coupled GPCR in cardiomyocytes and in cardiac fibroblasts. Stimulation of ERK5 by angiotensin II is blocked upon pharmacological inhibition or siRNA-mediated silencing of PKCz in primary cultures of cardiac cells and in cardiomyocytes isolated from PKCz-deficient mice. Moreover, these mice do not develop cardiac hypertrophy upon chronic challenge with angiotensin II, as assessed by morphological, biomarker, electrocardiographic and global gene expression pattern analysis. Conclusion/Significance: Our data put forward that PKC? is essential for Gq- dependent ERK5 activation in cardiac cells and indicate a key cardiac physiological role for this recently described Gaq/PKCz/MEK5 signaling axis. Littermate wild-type and PKCz -/- male mice (32 weeks of age) were subjected to continuous infusion of angiotensin II (or PBS as a control) for 14 days, a well established model for the induction of cardiac hypertrohy