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Mesenchymal-endothelial transition contributes to cardiac neovascularization.

Ubil E, Duan J, Pillai IC, Rosa-Garrido M, Wu Y, Bargiacchi F, Lu Y, Stanbouly S, Huang J, Rojas M, Vondriska TM, Stefani E, Deb A - Nature (2014)

Bottom Line: We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate.Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function.These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology &Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA.

ABSTRACT
Endothelial cells contribute to a subset of cardiac fibroblasts by undergoing endothelial-to-mesenchymal transition, but whether cardiac fibroblasts can adopt an endothelial cell fate and directly contribute to neovascularization after cardiac injury is not known. Here, using genetic fate map techniques, we demonstrate that cardiac fibroblasts rapidly adopt an endothelial-cell-like phenotype after acute ischaemic cardiac injury. Fibroblast-derived endothelial cells exhibit anatomical and functional characteristics of native endothelial cells. We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate. Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function. Conversely, stimulation of the p53 pathway in cardiac fibroblasts augments mesenchymal-to-endothelial transition, enhances vascularity and improves cardiac function. These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.

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Cardiac fibroblasts upregulate p53 after injury and p53 mediates MEndoT ex vivo(a,b) p53 immunostaining in injured hearts (arrowheads show tdTomato+P53+ cells) (c) Temporal p53 expression in labeled fibroblasts (*p<0.05 vs sham, n=3 animals/time point). (d) co-expression of p53, VECAD & tdTomato (arrowhead). (e,f) tdTomato+VECAD+ tubes and (g,h) AcLDL uptake after serum starvation (arrowheads, n=4). Scale bar: 250μm (h, right panel) Confocal image (XZ plane) showing AcLDL internalization (Scale bar: 20μm) (i–m) Tube formation of cardiac fibroblasts in (i)10% serum or 0% serum with (j) PBS (k) 100μM Pifithrin-α, (m) 0.1μM RITA, or (l) p53 deletion (bright field and fluorescence overlay). Scale bar: 250μm (n) Quantitation of tube length (** p<0.005 vs 10% serum. † p<0.005 and *p<0.05 vs starved cells, n=3). (o) Endothelial gene expression in cardiac fibroblasts (* p<0.005 vs 10% serum, † p<0.05 vs PBS, n=8). (p) ChIP with p53 (*p<0.05). (All graphs show mean±S.E.M., scale bar: 10μm unless mentioned).
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Figure 2: Cardiac fibroblasts upregulate p53 after injury and p53 mediates MEndoT ex vivo(a,b) p53 immunostaining in injured hearts (arrowheads show tdTomato+P53+ cells) (c) Temporal p53 expression in labeled fibroblasts (*p<0.05 vs sham, n=3 animals/time point). (d) co-expression of p53, VECAD & tdTomato (arrowhead). (e,f) tdTomato+VECAD+ tubes and (g,h) AcLDL uptake after serum starvation (arrowheads, n=4). Scale bar: 250μm (h, right panel) Confocal image (XZ plane) showing AcLDL internalization (Scale bar: 20μm) (i–m) Tube formation of cardiac fibroblasts in (i)10% serum or 0% serum with (j) PBS (k) 100μM Pifithrin-α, (m) 0.1μM RITA, or (l) p53 deletion (bright field and fluorescence overlay). Scale bar: 250μm (n) Quantitation of tube length (** p<0.005 vs 10% serum. † p<0.005 and *p<0.05 vs starved cells, n=3). (o) Endothelial gene expression in cardiac fibroblasts (* p<0.005 vs 10% serum, † p<0.05 vs PBS, n=8). (p) ChIP with p53 (*p<0.05). (All graphs show mean±S.E.M., scale bar: 10μm unless mentioned).

Mentions: We next investigated the mechanisms regulating MEndoT and hypothesized that cellular stress after cardiac injury plays a role in MEndoT. p53 is an important cellular stress response gene24, modulates reprogramming25 and regulates epithelial-mesenchymal-transition26. We observed that 37% of tdTomato labeled cardiac fibroblasts expressed p53 at 3 days post injury. In contrast, rare labeled cells expressed p53 in the sham injured heart (Fig. 2a,b). p53 expression in labeled fibroblasts peaked at 7 days after cardiac injury (Fig. 2c). By day 7 after injury, approximately 91±7% (mean±S.E.M.) of tdTomato labeled cells expressing p53 co-expressed VECAD (Fig. 2d), demonstrating a strong association between p53 and VECAD expression in tdTomato labeled cells.


Mesenchymal-endothelial transition contributes to cardiac neovascularization.

Ubil E, Duan J, Pillai IC, Rosa-Garrido M, Wu Y, Bargiacchi F, Lu Y, Stanbouly S, Huang J, Rojas M, Vondriska TM, Stefani E, Deb A - Nature (2014)

Cardiac fibroblasts upregulate p53 after injury and p53 mediates MEndoT ex vivo(a,b) p53 immunostaining in injured hearts (arrowheads show tdTomato+P53+ cells) (c) Temporal p53 expression in labeled fibroblasts (*p<0.05 vs sham, n=3 animals/time point). (d) co-expression of p53, VECAD & tdTomato (arrowhead). (e,f) tdTomato+VECAD+ tubes and (g,h) AcLDL uptake after serum starvation (arrowheads, n=4). Scale bar: 250μm (h, right panel) Confocal image (XZ plane) showing AcLDL internalization (Scale bar: 20μm) (i–m) Tube formation of cardiac fibroblasts in (i)10% serum or 0% serum with (j) PBS (k) 100μM Pifithrin-α, (m) 0.1μM RITA, or (l) p53 deletion (bright field and fluorescence overlay). Scale bar: 250μm (n) Quantitation of tube length (** p<0.005 vs 10% serum. † p<0.005 and *p<0.05 vs starved cells, n=3). (o) Endothelial gene expression in cardiac fibroblasts (* p<0.005 vs 10% serum, † p<0.05 vs PBS, n=8). (p) ChIP with p53 (*p<0.05). (All graphs show mean±S.E.M., scale bar: 10μm unless mentioned).
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Figure 2: Cardiac fibroblasts upregulate p53 after injury and p53 mediates MEndoT ex vivo(a,b) p53 immunostaining in injured hearts (arrowheads show tdTomato+P53+ cells) (c) Temporal p53 expression in labeled fibroblasts (*p<0.05 vs sham, n=3 animals/time point). (d) co-expression of p53, VECAD & tdTomato (arrowhead). (e,f) tdTomato+VECAD+ tubes and (g,h) AcLDL uptake after serum starvation (arrowheads, n=4). Scale bar: 250μm (h, right panel) Confocal image (XZ plane) showing AcLDL internalization (Scale bar: 20μm) (i–m) Tube formation of cardiac fibroblasts in (i)10% serum or 0% serum with (j) PBS (k) 100μM Pifithrin-α, (m) 0.1μM RITA, or (l) p53 deletion (bright field and fluorescence overlay). Scale bar: 250μm (n) Quantitation of tube length (** p<0.005 vs 10% serum. † p<0.005 and *p<0.05 vs starved cells, n=3). (o) Endothelial gene expression in cardiac fibroblasts (* p<0.005 vs 10% serum, † p<0.05 vs PBS, n=8). (p) ChIP with p53 (*p<0.05). (All graphs show mean±S.E.M., scale bar: 10μm unless mentioned).
Mentions: We next investigated the mechanisms regulating MEndoT and hypothesized that cellular stress after cardiac injury plays a role in MEndoT. p53 is an important cellular stress response gene24, modulates reprogramming25 and regulates epithelial-mesenchymal-transition26. We observed that 37% of tdTomato labeled cardiac fibroblasts expressed p53 at 3 days post injury. In contrast, rare labeled cells expressed p53 in the sham injured heart (Fig. 2a,b). p53 expression in labeled fibroblasts peaked at 7 days after cardiac injury (Fig. 2c). By day 7 after injury, approximately 91±7% (mean±S.E.M.) of tdTomato labeled cells expressing p53 co-expressed VECAD (Fig. 2d), demonstrating a strong association between p53 and VECAD expression in tdTomato labeled cells.

Bottom Line: We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate.Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function.These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology &Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA.

ABSTRACT
Endothelial cells contribute to a subset of cardiac fibroblasts by undergoing endothelial-to-mesenchymal transition, but whether cardiac fibroblasts can adopt an endothelial cell fate and directly contribute to neovascularization after cardiac injury is not known. Here, using genetic fate map techniques, we demonstrate that cardiac fibroblasts rapidly adopt an endothelial-cell-like phenotype after acute ischaemic cardiac injury. Fibroblast-derived endothelial cells exhibit anatomical and functional characteristics of native endothelial cells. We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate. Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function. Conversely, stimulation of the p53 pathway in cardiac fibroblasts augments mesenchymal-to-endothelial transition, enhances vascularity and improves cardiac function. These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.

Show MeSH
Related in: MedlinePlus