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. Author manuscript; available in PMC: 2017 Jan 8.
Published in final edited form as: Circ Res. 2016 Jan 8;118(1):95–107. doi: 10.1161/CIRCRESAHA.115.305373

Figure 2. Paracrine factors are pleiotropic.

Figure 2

For illustration, we show the cellular effects of 2 selective paracrine factors on the cardiomyocyte. Left: HASF and Sfrp2 inhibit cardiomyocyte apoptosis through divergent pathways. HASF, following binding to a growth factor receptor, inhibits cytochrome release from mitochondria via PKCe. In contrast Sfrp2 inhibits Wnt activation of Frizzled Receptors. This induces b-catenin degradation via the APC complex. Right: Abi3bp and Sfrp2 promote cardiac progenitor cell differentiation as well as inhibiting proliferation. Abi3bp activates integrin-b1. Src and ERK activation work together to inhibit proliferation. PKCz and Akt activation switch on cardiac genes. Sfrp2 sequesters Wnt, preventing activation of Frizzled Receptors. This promotes JNK activation and cardiac gene expression. Inhibition of b-catenin blocks the proliferation pathway in these cells.