Figure 1.

Characterization and Differentiation of Adult CPCs

(A) Expression of early (GATA4, MEF2C, NKX2.5) and late cardiac markers (MYH6, MYH7, TNNI, CX43) in the human adult heart and in isolated cardiac precursor cells (CPCs). (B) Flow cytometry analysis of CD31, CD34, CD45, CD73, CD90, CD105, CD117, CXCR4, CD140a, CD146, and NG2 expression in adult CPCs. Histograms show control (gray) and specific fluorescent intensity signal (white). (C) Analysis of cardiac transcription factor and proliferation marker expression by immunostaining. Nuclei were stained with DAPI (blue). Scale bar: 20 μm. Quantification of NKX2.5^POS/GATA4^POS, NKX2.5^POS/MEF2C^POS, NKX2.5^POS/PH3^POS, and NKX2.5^POS/KI67^POS CPCs. Data represent mean ± SEM (minimum 4,000 cells in 50 different fields at a magnification of 40× per quantification). (D) Gene expression of MYH6, MYH7, TNNI, ACTA, and MYH11 in proliferating CPCs (Expansion; black) and in adult CPCs exposed to DLL1 (gray), and differentiated in the absence (upper panels) or presence of DAPT (lower panels). Data represent mean ± SEM; *p < 0.05 as compared with proliferating CPCs; ‡p < 0.05 as compared with differentiating unstimulated (None; white) CPCs in absence of DAPT (n = 5). (E) Analysis of SM-MHC and α-ACTININ expression by immunostaining in CPCs exposed or not to DLL1 and differentiated in the absence or presence of DAPT. Nuclei were stained with DAPI (blue). Scale bars: 20 μm. (F) Quantification of SM-MHC^POS and α-ACTININ^POS in adult CPCs exposed to DLL1 (gray), and differentiated in the absence or presence of DAPT. Data represent mean ± SEM; *p < 0.05 as compared with proliferating CPCs; ‡p < 0.05 as compared with differentiating unstimulated (None) (white) CPCs in absence of DAPT (minimum 2,000 cells in 30 different fields at a magnification of 40× per quantification). Diff = differentiation medium; Exp = expansion medium.