TY  - JOUR
A1  - Andrés-Delgado, Laura
A1  - Ernst, Alexander
A1  - Galardi-Castilla, María
A1  - Bazaga, David
A1  - Peralta, Marina
A1  - Münch, Juliane
A1  - Gonzalez-Rosa, Juan M.
A1  - Marques, Inês
A1  - Tessadori, Federico
A1  - de la Pompa, José Luis
A1  - Vermot, Julien
A1  - Mercader, Nadia
T1  - Actin dynamics and the Bmp pathway drive apical extrusion of proepicardial cells
JF  - Development : Company of Biologists
N2  - The epicardium, the outer mesothelial layer enclosing the myocardium, plays key roles in heart development and regeneration. During embryogenesis, the epicardium arises from the proepicardium (PE), a cell cluster that appears in the dorsal pericardium (DP) close to the venous pole of the heart. Little is known about how the PE emerges from the pericardial mesothelium. Using a zebrafish model and a combination of genetic tools, pharmacological agents and quantitative in vivo imaging, we reveal that a coordinated collective movement of DP cells drives PE formation. We found that Bmp signaling and the actomyosin cytoskeleton promote constriction of the DP, which enables PE cells to extrude apically. We provide evidence that cell extrusion, which has been described in the elimination of unfit cells from epithelia and the emergence of hematopoietic stem cells, is also a mechanism for PE cells to exit an organized mesothelium and fulfil their developmental fate to form a new tissue layer, the epicardium.
KW  - Actomyosin
KW  - Bmp
KW  - Cell extrusion
KW  - Proepicardium
KW  - Zebrafish
KW  - Heart development
Y1  - 2019
U6  - https://doi.org/10.1242/dev.174961
SN  - 0950-1991
SN  - 1477-9129
VL  - 146
IS  - 13
PB  - The Company of Biologists Ltd
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Uribe, Veronica
A1  - Ramadass, Radhan
A1  - Dogra, Deepika
A1  - Rasouli, S. Javad
A1  - Gunawan, Felix
A1  - Nakajima, Hiroyuki
A1  - Chiba, Ayano
A1  - Reischauer, Sven
A1  - Mochizuki, Naoki
A1  - Stainier, Didier Y. R.
T1  - In vivo analysis of cardiomyocyte proliferation during trabeculation
JF  - Development : Company of Biologists
N2  - Cardiomyocyte proliferation is crucial for cardiac growth, patterning and regeneration; however, few studies have investigated the behavior of dividing cardiomyocytes in vivo. Here, we use time-lapse imaging of beating hearts in combination with the FUCCI system to monitor the behavior of proliferating cardiomyocytes in developing zebrafish. Confirming in vitro observations, sarcomere disassembly, as well as changes in cell shape and volume, precede cardiomyocyte cytokinesis. Notably, cardiomyocytes in zebrafish embryos and young larvae mostly divide parallel to the myocardial wall in both the compact and trabecular layers, and cardiomyocyte proliferation is more frequent in the trabecular layer. While analyzing known regulators of cardiomyocyte proliferation, we observed that the Nrg/ErbB2 and TGF beta signaling pathways differentially affect compact and trabecular layer cardiomyocytes, indicating that distinct mechanisms drive proliferation in these two layers. In summary, our data indicate that, in zebrafish, cardiomyocyte proliferation is essential for trabecular growth, but not initiation, and set the stage to further investigate the cellular and molecular mechanisms driving cardiomyocyte proliferation in vivo.
KW  - Heart development
KW  - Cardiomyocyte proliferation
KW  - Trabeculation
KW  - Sarcomere
Y1  - 2018
U6  - https://doi.org/10.1242/dev.164194
SN  - 0950-1991
SN  - 1477-9129
VL  - 145
IS  - 14
PB  - Company biologists LTD
CY  - Cambridge
ER  -