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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 adopt endothelial cell fates after cardiac injury(a,b) Hearts from Col1a2CreERT:R26RtdTomato immunostained for endothelial markers (arrowheads) (c) tdTomato+ fibroblasts(%) expressing endothelial markers (*p<0.05 vs sham, † p<0.05 vs injury border zone). (d) Temporal expression of VECAD (* p<0.005 vs sham, †p<0.05 vs Day 1 and 2, $ p<0.05 vs Day 1,). (e) STED microscopy demonstrating tdTomato+VECAD+ cell (arrowhead; unfilled arrowhead shows tdTomato- endothelial cell) (f–h) DiO stained capillary in (f,g) longitudinal section (arrowheads show tdTomato+DiO+ cells) or (h) cross-section (cyan arrowheads show DiO stained inner and outer endothelial cell membranes, white arrowheads show tdTomato+ endothelial cell; unfilled arrowhead shows tdTomato- endothelial cell). Scale bar: 5μm. (i) Luminal surface area occupied by fibroblast derived endothelium (* p<0.005 vs sham, † p<0.05 vs Day 3). (j) AcLDL uptake by tdTomato+ endothelium (arrowheads). (n=3 animals /group/ time point, All graphs show mean±S.E.M., scale bar:10μm unless mentioned)
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Figure 1: Cardiac fibroblasts adopt endothelial cell fates after cardiac injury(a,b) Hearts from Col1a2CreERT:R26RtdTomato immunostained for endothelial markers (arrowheads) (c) tdTomato+ fibroblasts(%) expressing endothelial markers (*p<0.05 vs sham, † p<0.05 vs injury border zone). (d) Temporal expression of VECAD (* p<0.005 vs sham, †p<0.05 vs Day 1 and 2, $ p<0.05 vs Day 1,). (e) STED microscopy demonstrating tdTomato+VECAD+ cell (arrowhead; unfilled arrowhead shows tdTomato- endothelial cell) (f–h) DiO stained capillary in (f,g) longitudinal section (arrowheads show tdTomato+DiO+ cells) or (h) cross-section (cyan arrowheads show DiO stained inner and outer endothelial cell membranes, white arrowheads show tdTomato+ endothelial cell; unfilled arrowhead shows tdTomato- endothelial cell). Scale bar: 5μm. (i) Luminal surface area occupied by fibroblast derived endothelium (* p<0.005 vs sham, † p<0.05 vs Day 3). (j) AcLDL uptake by tdTomato+ endothelium (arrowheads). (n=3 animals /group/ time point, All graphs show mean±S.E.M., scale bar:10μm unless mentioned)

Mentions: We subjected Col1a2CreERT:R26RtdTomato mice to ischemia-reperfusion cardiac injury 5 days following cessation of tamoxifen injection. By day 3 post-injury, 35±3% (mean±S.E.M) of labeled cardiac fibroblasts in the region of injury expressed the endothelial specific marker VECAD, while in sham injured animals only rare labeled cells expressed VECAD (<0.3%) (Fig. 1a–c). Approximately 24±4%, 44±4% and 35±3% (mean±S.E.M) of labeled cardiac fibroblasts also expressed other endothelial markers such as endothelial nitric oxide synthase (eNOS) and the endothelial tight junctional proteins Claudin 514 and Occludin14 respectively (Fig. 1a–c). MEndoT was most pronounced in the injury border zone significantly decreasing in regions remote from the infarct. (Fig. 1c). The fraction of cardiac fibroblasts expressing VECAD increased between 1 and 3 days post-injury and remained similar at 3, 7 and 14 days (Fig. 1d). The fraction of tdTomato positive cells expressing VECAD in sham injured animals at 3, 7 and 14 days was 0.3±0.1%, 1.4±1.4% and 0.6±0.4% (mean±S.E.M., p>0.05, one way Anova) demonstrating no temporal difference in the fraction of tdTomato labeled cells expressing VECAD following sham injury.


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 adopt endothelial cell fates after cardiac injury(a,b) Hearts from Col1a2CreERT:R26RtdTomato immunostained for endothelial markers (arrowheads) (c) tdTomato+ fibroblasts(%) expressing endothelial markers (*p<0.05 vs sham, † p<0.05 vs injury border zone). (d) Temporal expression of VECAD (* p<0.005 vs sham, †p<0.05 vs Day 1 and 2, $ p<0.05 vs Day 1,). (e) STED microscopy demonstrating tdTomato+VECAD+ cell (arrowhead; unfilled arrowhead shows tdTomato- endothelial cell) (f–h) DiO stained capillary in (f,g) longitudinal section (arrowheads show tdTomato+DiO+ cells) or (h) cross-section (cyan arrowheads show DiO stained inner and outer endothelial cell membranes, white arrowheads show tdTomato+ endothelial cell; unfilled arrowhead shows tdTomato- endothelial cell). Scale bar: 5μm. (i) Luminal surface area occupied by fibroblast derived endothelium (* p<0.005 vs sham, † p<0.05 vs Day 3). (j) AcLDL uptake by tdTomato+ endothelium (arrowheads). (n=3 animals /group/ time point, All graphs show mean±S.E.M., scale bar:10μm unless mentioned)
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4214889&req=5

Figure 1: Cardiac fibroblasts adopt endothelial cell fates after cardiac injury(a,b) Hearts from Col1a2CreERT:R26RtdTomato immunostained for endothelial markers (arrowheads) (c) tdTomato+ fibroblasts(%) expressing endothelial markers (*p<0.05 vs sham, † p<0.05 vs injury border zone). (d) Temporal expression of VECAD (* p<0.005 vs sham, †p<0.05 vs Day 1 and 2, $ p<0.05 vs Day 1,). (e) STED microscopy demonstrating tdTomato+VECAD+ cell (arrowhead; unfilled arrowhead shows tdTomato- endothelial cell) (f–h) DiO stained capillary in (f,g) longitudinal section (arrowheads show tdTomato+DiO+ cells) or (h) cross-section (cyan arrowheads show DiO stained inner and outer endothelial cell membranes, white arrowheads show tdTomato+ endothelial cell; unfilled arrowhead shows tdTomato- endothelial cell). Scale bar: 5μm. (i) Luminal surface area occupied by fibroblast derived endothelium (* p<0.005 vs sham, † p<0.05 vs Day 3). (j) AcLDL uptake by tdTomato+ endothelium (arrowheads). (n=3 animals /group/ time point, All graphs show mean±S.E.M., scale bar:10μm unless mentioned)
Mentions: We subjected Col1a2CreERT:R26RtdTomato mice to ischemia-reperfusion cardiac injury 5 days following cessation of tamoxifen injection. By day 3 post-injury, 35±3% (mean±S.E.M) of labeled cardiac fibroblasts in the region of injury expressed the endothelial specific marker VECAD, while in sham injured animals only rare labeled cells expressed VECAD (<0.3%) (Fig. 1a–c). Approximately 24±4%, 44±4% and 35±3% (mean±S.E.M) of labeled cardiac fibroblasts also expressed other endothelial markers such as endothelial nitric oxide synthase (eNOS) and the endothelial tight junctional proteins Claudin 514 and Occludin14 respectively (Fig. 1a–c). MEndoT was most pronounced in the injury border zone significantly decreasing in regions remote from the infarct. (Fig. 1c). The fraction of cardiac fibroblasts expressing VECAD increased between 1 and 3 days post-injury and remained similar at 3, 7 and 14 days (Fig. 1d). The fraction of tdTomato positive cells expressing VECAD in sham injured animals at 3, 7 and 14 days was 0.3±0.1%, 1.4±1.4% and 0.6±0.4% (mean±S.E.M., p>0.05, one way Anova) demonstrating no temporal difference in the fraction of tdTomato labeled cells expressing VECAD following sham injury.

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