The generation of cardiosphere from adult heart and the implication of LPAR4+ cardiac progenitor cells for the treatment in ischemic heart disease

Abstract

Cardiac stem cells are found only in small numbers in the adult heart. As a strategy to overcome the limitation of insufficient cell numbers, cardiosphere-derived cells (CDCs) have been previously introduced. Since two-dimensional CDCs showed lower stemness than 3-dimensional form, re-creating sphere from attached CDCs could overcome such barrier. Nevertheless, repeated primary culture remains as technical huddle due to passage-dependent loss of stemness. Here, I proposed a method for stemness recovery by 3-dimensional culture, and an extension strategy for enriched number of phase-bright cells obtained from heart tissue by ex vivo culture. To screen a specific marker of phase-bright cells, microarray data analysis was performed. Lysophosphatidic acid receptor 4 (LPAR4) was increased in most of phase-bright cells. A higher number of phase-bright cells were generated after treatment of 1μM LPA. Simultaneously, the expression of stemness related genes were increased together in a 3-dimensional form and by LPA treatment. The LPAR4 expressed phase-bright cells cultured in 3-dimension were then differentiated into cardiomyocytes. FACS analysis showed that the markers of cardiomyocyte, troponin-T andα-SA were more highly expressed than differentiation of CDC control group. In conclusion, the acquired phase-bright cells with sufficient cell number and 3-dimensional form can be useful for differentiation into cardiomyocyte. The expression of LPAR4 in adult cardiac progenitors associates with the activation of cardiac progenitor cells for the differentiation into cardiomyocyte.