Functional recovery of the infarcted heart is enhanced by the loss of E2F2 expression and impaired by the loss of endothelial E2F3 expression.

<p>MI was surgically induced in VE-Cre; E2F3^fl/fl and E2F2 KO mice and their WT littermates, VE-Cre; E2F3^+/+ and E2F2 WT, respectively, and the heart function was assessed with echocardiography at the indicated time points for (<b>A</b>) LV ejection fraction, (<b>B</b>) fractional shortening, (<b>C</b>) end-systolic and (<b>D</b>) end-diastolic volumes. n = 12 mice per group. *P<0.05 vs. VE-Cre; E2F3^+/+, ^#P<0.05 vs. E2F2 WT.</p

The vascular density at infarct border zone is greater in E2F2 KO mice and lower in endothelial E2F3 KO mice than in their WT littermates.

<p>Blood vessels were stained with BS lectin 1 (green), and nuclei were counterstained with DAPI (blue). (<b>A</b>) Representative immunofluorescence images. (<b>B</b>) Quantification of vascular density at the infarct border zone. n = 12 mice per group; *P<0.05 vs. VE-Cre; E2F3^+/+, ^#P<0.05 vs. E2F2 WT; HPF, high power field.</p

Proliferation is enhanced in E2F2 KO ECs and impaired in E2F3-deleted ECs.

<p><b>(A–B)</b> Immunofluorescent double staining was performed in the ischemic heart sections for CD31 (green) and BrdU (red) to identify ECs (green), proliferating cells (red), and proliferating ECs (yellow). (<b>A</b>) Representative immunofluorescence images and (<b>B</b>) quantification of proliferating ECs in the infarct border zone. n = 12 mice per group; *P<0.05 vs. VE-Cre; E2F3^+/+, ^#P<0.05 vs. E2F2 WT; HPF, high power field. (<b>C</b>) Primary ECs were isolated from the hearts of E2F2 KO, E2F2 WT, and E2F3^fl/fl mice, and the E2F3^fl/fl cells were subsequently transduced with Adenovirus-Cre/GFP or Adenovirus-GFP. EdU incorporation based flow cytometry analyses were performed to assess DNA synthesis. Shown is representative of 3 independent experiments.</p

The infarct size is smaller in E2F2 KO mice and larger in endothelial specific E2F3 KO mice than in their WT littermates.

<p>Masson Trichrome staining was performed in heart samples 28 days after MI surgery. (<b>A</b>) Representative microphotographs and (<b>B</b>) Quantification of the infarct size. n = 12 mice per group; *P<0.05 versus VE-Cre; E2F3^+/+, ^#P<0.05 versus E2F2 WT; Scale bar = 100 µm.</p