Fig. 6
Figure 6. Macrophages stimulate epicardial cell number expansion following cardiac injury (A) Image of an uninjured 3 dpf ventricle from a Tg(myl7:mKateCAAX;myl7:h2b-GFP) larva showing vegfaa+ cells (green) overlying myocardium (magenta). Cyan box, zoom panel. (B) Images of uninjured and injured ventricles from Tg(vegfaa:GFP) larvae acquired at 48 hpi. “Heat” LUT is applied to highlight the increased intensity of epicardial vegfaa:GFP in injured hearts. (C) Total ventricular vegfaa:GFP fluorescence in uninjured and injured hearts over standard injury model time points, n = 28–30. ∗ p ≤ 0.05 one-way ANOVA followed by Holms-Sidak’s multiple comparison post-hoc tests. (D and E) Images of uninjured and injured EdU-stained Tg(vegfaa:GFP) hearts 48 hpi showing EdU+ epicardial cells (white arrowheads) and the proportion of EdU+ epicardial cells are quantified in (E), n = 13–16. Unpaired t test, ∗∗ p ≤ 0.01. (F) Image of a ventricle from a Tg(vegfaa:GFP;csfr1a:NfsB-mCherry;kdrl:hsa.HRAS-mCherry) (abbreviated to kdrl:mCherry) larva at 48 hpi showing macrophages in the epicardial-myocardial niche (white arrowheads). Cyan box, zoom panel. (G) Images of uninjured and injured ventricles from Tg(vegfaa:GFP;csfr1a:NfsB-mCherry) larvae from metronidazole-nitroreductase macrophage ablation groups at 48 hpi. “Heat” LUT is applied to highlight the increase in the overall fluorescence in injured groups except NTR+met+. Total vegfaa:GFP fluorescence (H) and epicardial cell number (I) in uninjured and injured ventricles from Tg(vegfaa:GFP;csfr1a:NfsB-mCherry) larvae from metronidazole-nitroreductase macrophage ablation groups at 48 hpi. All images are maximum intensity projections of 3D LSFM stacks. Scale bars, 50 μm, n = 46. ∗ p ≤ 0.05, ∗∗ p ≤ 0.01, ∗∗∗p ≤ 0.001. One-way ANOVA followed by Holms-Sidak’s multiple comparison post-hoc tests. Data are represented as mean ± SEM.
Reprinted from Developmental Cell, 57(12), Bruton, F.A., Kaveh, A., Ross-Stewart, K.M., Matrone, G., Oremek, M.E.M., Solomonidis, E.G., Tucker, C.S., Mullins, J.J., Lucas, C.D., Brittan, M., Taylor, J.M., Rossi, A.G., Denvir, M.A., Macrophages trigger cardiomyocyte proliferation by increasing epicardial vegfaa expression during larval zebrafish heart regeneration, 1512-1528.e5, Copyright (2022) with permission from Elsevier. Full text @ Dev. Cell