Figure 6.

Notch signaling modulates in vivo CPC number and proliferation. The γ-secreatse inhibitor DAPT reduces Notch activation in infarcted hearts (a,b) and in CPCs isolated from HMGB1-treated infarcted hearts (c,d). DAPT was administered to mice 1 day before, 1 and 2 days after MI. The zone bordering the infarct was collected from six different mouse hearts and three of them were used for Western blot analysis while the others were subjected to qRT-PCR. (a) Western blot analysis was performed on heart extracts and on control brain samples (positive control), to detect NICD1. The same filter was probed with anti-Notch1 antibody. DAPT reduced NICD levels. (b) DAPT inhibited the expression of Notch-regulated genes, that is, hes, hey and jagged1 (n = 3, *P < 0.05 vs. each control). CPCs expressing c-kit (c) and c-kit/Ki67 (d) were isolated from infarcted hearts in the absence (-) and in presence (+) of DAPT, 3 days following MI and HMGB1 administration (n = 16/each group). Lower panel: representative image of double immunofluorescence showing freshly isolated CPCs from HMGB1-treated hearts stained for c-kit (red fluorescence) and Ki67 (green fluorescence). Hoechst staining of nuclei in blue.