Soluble factors released by dedifferentiated fat cells reduce the functional activity of iPS cell‐derived cardiomyocytes

Interactions between tissues such as epicardial adipose (EAT), and myocardial tissues is important in the pathogenesis of heart failure. Changes in adipose tissues in obesity or diabetes impair preadipocyte differentiation. Furthermore, proinflammatory cytokine secretion is higher in preadipocytes than in mature adipocytes in diabetes and obesity. However, how undifferentiated cells committed to the adipose lineage directly influence cardiomyocytes is not yet understood. We used human-derived dedifferentiated fat (DFAT) cells as models of undifferentiated cells committed to an adipose lineage. Here, we evaluated the effects of soluble factor interactions in indirect cocultures of DFAT cells and induced pluripotent stem cell-derived cardiomyocytes. Our RNA sequencing findings showed that these interactions were predominantly inflammatory responses. Furthermore, proinflammatory cytokines secreted by DFAT cells reduced myocardial functions such as contraction frequency and catecholamine sensitivity, and simultaneously increased apoptosis, decreased antioxidative stress tolerance, and reduced oxygen consumption rates in cardiomyocytes. These adverse effects might be attributable to monocyte chemoattractant protein-1, chemokine (C-X-C motif) ligands 1 (CXCL1), and 12, granulocyte colony-stimulating factor, interleukins 6 and 8, macrophage migration inhibitory factor (MIF), and plasminogen activator inhibitor 1-A among the proinflammatory mediators secreted by DFAT cells. Our results could be useful for understanding the pathogenesis of EAT-related heart failure in terms of the involvement of undifferentiated cells committed to the adipose lineage. Furthermore, we suggest the importance of focusing on surrounding adipose tissues as a strategy with which to maximize the survival and function of transplanted stem cell-derived cardiomyocytes.