The reprogramming of fibroblast cells to induced pluripotent stem (iPS) cells raises the possibility that a somatic cell could be reprogrammed to an alternative differentiated fate without first becoming a stem/progenitor cell. A large pool of fibroblast cells exists in the post-natal heart, yet no single master regulator of direct cardiac reprogramming has been identified. Here, we report that a combination of three developmental transcription factors (i.e., Gata4, Mef2c and Tbx5) rapidly and efficiently reprogrammed post-natal cardiac or tail-tip fibroblasts directly into differentiated cardiomyocyte-like cells. Induced cardiomyocytes expressed cardiac-specific markers, had a global gene expression profile similar to cardiomyocytes, and contracted spontaneously. Fibroblast cells transplanted into mouse hearts one day after transduction of the three factors also differentiated into cardiomyocyte-like cells. These findings demonstrate that functional cardiomyocytes can be directly reprogrammed from differentiated somatic cells by defined factors. Reprogramming of endogenous or explanted fibroblast cells might provide a source of cardiomyocytes for regenerative approaches.
Direct reprogramming of fibroblasts into functional cardiomyocytes by defined factors.
Specimen part
View SamplesGrowth and expansion of ventricular chambers is essential during cardiogenesis and is achieved by proliferation of cardiac progenitors that are not fully differentiated. Disruption of this process can lead to prenatal lethality. In contrast, adult cardiomyocytes achieve growth through hypertrophy rather than hyperplasia. Although epicardial-derived signals may contribute to the proliferative process in myocytes, the factors and cell types responsible for development of the ventricular myocardial thickness are unclear. Moreover, the function of embryonic cardiac fibroblasts, derived from epicardium, and their secreted factors are largely unknown. Using a novel co-culture system, we found that embryonic cardiac fibroblasts induced proliferation of cardiomyocytes, in contrast to adult cardiac fibroblasts that promoted myocyte hypertrophy. We identified fibronectin, collagen and heparin-binding EGF-like growth factor as embryonic cardiac fibroblast-specific signals that collaboratively promoted cardiomyocyte proliferation in a paracrine fashion. b1 integrin was required for this proliferative response, and ventricular cardiomyocyte-specific deletion of b1 integrin in mice resulted in reduced myocardial proliferation and impaired ventricular compaction. These findings reveal a previously unrecognized paracrine function of embryonic cardiac fibroblasts in regulating cardiomyocyte proliferation.
Cardiac fibroblasts regulate myocardial proliferation through beta1 integrin signaling.
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View SamplesGrowth and expansion of ventricular chambers is essential during cardiogenesis and is achieved by proliferation of cardiac progenitors that are not fully differentiated. Disruption of this process can lead to prenatal lethality. In contrast, adult cardiomyocytes achieve growth through hypertrophy rather than hyperplasia. Although epicardial-derived signals may contribute to the proliferative process in myocytes, the factors and cell types responsible for development of the ventricular myocardial thickness are unclear. Moreover, the function of embryonic cardiac fibroblasts, derived from epicardium, and their secreted factors are largely unknown. Using a novel co-culture system, we found that embryonic cardiac fibroblasts induced proliferation of cardiomyocytes, in contrast to adult cardiac fibroblasts that promoted myocyte hypertrophy. We identified fibronectin, collagen and heparin-binding EGF-like growth factor as embryonic cardiac fibroblast-specific signals that collaboratively promoted cardiomyocyte proliferation in a paracrine fashion. b1 integrin was required for this proliferative response, and ventricular cardiomyocyte-specific deletion of b1 integrin in mice resulted in reduced myocardial proliferation and impaired ventricular compaction. These findings reveal a previously unrecognized paracrine function of embryonic cardiac fibroblasts in regulating cardiomyocyte proliferation.
Cardiac fibroblasts regulate myocardial proliferation through beta1 integrin signaling.
No sample metadata fields
View SamplesGrowth and expansion of ventricular chambers is essential during cardiogenesis and is achieved by proliferation of cardiac progenitors that are not fully differentiated. Disruption of this process can lead to prenatal lethality. In contrast, adult cardiomyocytes achieve growth through hypertrophy rather than hyperplasia. Although epicardial-derived signals may contribute to the proliferative process in myocytes, the factors and cell types responsible for development of the ventricular myocardial thickness are unclear. Moreover, the function of embryonic cardiac fibroblasts, derived from epicardium, and their secreted factors are largely unknown. Using a novel co-culture system, we found that embryonic cardiac fibroblasts induced proliferation of cardiomyocytes, in contrast to adult cardiac fibroblasts that promoted myocyte hypertrophy. We identified fibronectin, collagen and heparin-binding EGF-like growth factor as embryonic cardiac fibroblast-specific signals that collaboratively promoted cardiomyocyte proliferation in a paracrine fashion. b1 integrin was required for this proliferative response, and ventricular cardiomyocyte-specific deletion of b1 integrin in mice resulted in reduced myocardial proliferation and impaired ventricular compaction. These findings reveal a previously unrecognized paracrine function of embryonic cardiac fibroblasts in regulating cardiomyocyte proliferation.
Cardiac fibroblasts regulate myocardial proliferation through beta1 integrin signaling.
No sample metadata fields
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