Project description:Sox17-Erg direct reprogramming converts neonatal murine cardiac fibroblasts into induced endothelial cells. This data evaluates the conversion over time of the Sox17-Erg iECs compared to control condition.
Project description:Cardiac muscle differentiation in vivo is guided by sequential growth factor signals, including endoderm-derived diffusible factors, impinging on cardiogenic genes in the developing mesoderm. Previously, by RNA interference in AB2.2 mouse embryonic stem cells (mESCs), we identified the endodermal transcription factor Sox17 as essential for Mesp1 induction in primitive mesoderm and subsequent cardiac muscle differentiation. However, downstream effectors of Sox17 remained to be proven functionally. In this study, we used genome-wide profiling of Sox17-dependent genes in AB2.2 cells, RNA interference, chromatin immunoprecipitation, and luciferase reporter genes to dissect this pathway. Sox17 was required not only for Hhex (a second endodermal transcription factor) but also for Cer1, a growth factor inhibitor from endoderm that, like Hhex, controls mesoderm patterning in Xenopus toward a cardiac fate. Suppressing Hhex or Cer1 blocked cardiac myogenesis, although at a later stage than induction of Mesp1/2. Hhex was required but not sufficient for Cer1 expression. Over-expression of Sox17 induced endogenous Cer1 and sequence-specific transcription of a Cer1 reporter gene. Forced expression of Cer1 was sufficient to rescue cardiac differentiation in Hhex-deficient cells. Thus, Hhex and Cer1 are indispensable components of the Sox17 pathway for cardiopoiesis in mESCs, acting at a stage downstream from Mesp1/2. Keywords: Cardiac development, Embryonic stem cells, Endoderm, Myogenesis, RNA interference Genome-wide expression profiling of Sox17-dependent genes. Mouse embryonic stem cells expressing Sox17 or luciferase shRNA were differentiated for up to 10 days by the embryoid body method [PMID:8155574], then were analysed using Affymetrix microarrays. ESCs were transduced with lentiviral vectors coexpressing enhanced green fluorescent protein (eGFP) with shRNA against Sox17, or against firefly luciferase. Transduced cells were flow-sorted based on GFP fluorescence, grown as embryoid bodies, and transferred to tissue culture plates after 4.5 days [PMID:17360443]. Cells were harvested at days 0, 2, 4, 5, 6, 8 and 10 in two biological replicates, except where noted.
Project description:Cardiac muscle differentiation in vivo is guided by sequential growth factor signals, including endoderm-derived diffusible factors, impinging on cardiogenic genes in the developing mesoderm. Previously, by RNA interference in AB2.2 mouse embryonic stem cells (mESCs), we identified the endodermal transcription factor Sox17 as essential for Mesp1 induction in primitive mesoderm and subsequent cardiac muscle differentiation. However, downstream effectors of Sox17 remained to be proven functionally. In this study, we used genome-wide profiling of Sox17-dependent genes in AB2.2 cells, RNA interference, chromatin immunoprecipitation, and luciferase reporter genes to dissect this pathway. Sox17 was required not only for Hhex (a second endodermal transcription factor) but also for Cer1, a growth factor inhibitor from endoderm that, like Hhex, controls mesoderm patterning in Xenopus toward a cardiac fate. Suppressing Hhex or Cer1 blocked cardiac myogenesis, although at a later stage than induction of Mesp1/2. Hhex was required but not sufficient for Cer1 expression. Over-expression of Sox17 induced endogenous Cer1 and sequence-specific transcription of a Cer1 reporter gene. Forced expression of Cer1 was sufficient to rescue cardiac differentiation in Hhex-deficient cells. Thus, Hhex and Cer1 are indispensable components of the Sox17 pathway for cardiopoiesis in mESCs, acting at a stage downstream from Mesp1/2. Keywords: Cardiac development, Embryonic stem cells, Endoderm, Myogenesis, RNA interference
Project description:The functional consequences of cancer-associated missense mutations are unclear for majority of proteins, here we interrogated cancer mutation databases and identified recurrently mutated positions at structural contact interface of DNA-binding domains of SOX and POU family transcription factors. We used conversion of mouse embryonic fibroblasts (MEFs) to induced pluripotent stem cells (iPSCs) as a functional read out. In this study we identified several gain-of-function mutations that enhance cellular pluripotency reprogramming by SOX2 and OCT4. Wild type SOX17 does not support pluripotency reprogramming while recurrent missense mutation SOX17-V118M converts SOX17 into a pluripotency inducer, viability of cancer cells and provides protein stability. Here, we conclude that mutational profile of SOX and OCT family factors in cancer association can give direction to design high-performance reprogramming factors.
Project description:Mouse somatic cells can be chemically reprogrammed into pluripotent stem cells (CiPSCs) through an intermediate extraembryonic endoderm (XEN)-like state. However, it is elusive how the chemicals orchestrate the cell fate alteration. In this study, we analyze molecular dynamics in chemical reprogramming from fibroblasts to a XEN-like state. We find that Sox17 is initially activated by the chemical cocktails, and XEN cell fate specialization is subsequently mediated by Sox17 activated expression of other XEN master genes, such as Sall4 and Gata4. Furthermore, this stepwise process is differentially regulated. The core reprogramming chemicals CHIR99021, 616452 and Forskolin are all necessary for Sox17 activation, while differently required for Gata4 and Sall4 expression. The addition of chemical boosters in different phases further improves the generation efficiency of XEN-like cells. Taken together, our work demonstrates that chemical reprogramming is regulated in 3 distinct “prime–specify–transit” phases initiated with endogenous Sox17 activation, providing a new framework to understand cell fate determination.
Project description:Direct cardiac reprogramming from fibroblasts holds great potential for disease modeling, drug screening, and regeneration. However, cardiac reprogramming remains inefficient in vitro, and induced cardiomyocytes (iCMs) generated in vitro are less mature than those in vivo, suggesting undefined biophysical factors may inhibit cardiac reprogramming. Previous studies mainly used conventional polystyrene dishes, and thus the effect of matrix rigidity on cardiac reprogramming remains unclear. Here, we developed a Matrigel-based hydrogel culture system to determine the effect of matrix rigidity and mechanotransduction on cardiac reprogramming. We found that soft matrix rigidity comparable to myocardium greatly enhanced cardiac reprogramming in combination with Gata4, Hand2, Mef2c, and Tbx5. Mechanistically, soft matrix enhanced cardiac reprogramming via inhibition of Rho/ROCK, actomyosin, and YAP/TAZ pathway, and suppression of fibroblast program, which were activated on rigid substrate. Intriguingly, inhibition of YAP/TAZ further suppressed integrin-mediated signaling to create a positive feedback loop for robust reprogramming. Thus, mechanotransduction may represent a new target for cardiac reprogramming.