: Analysis of cardiac looping morphogenesis in the zebrafish model

LOMBARDO V.A.; ARMESTO R.; HEISE M.; ABDELILAH-SEYFRIED, S.

Congreso; REUNION ANUAL SAFIS-ALACF 2021; 2021

SAFIS & ALACF

Cardiac looping is a morphogenetic process during vertebrate heart development which brings the developing heart chambers into an approximation of their definitive topographical relationships. Abnormalities in this process result in human congenital heart defects. The aim of this work was to investigate cardiac looping morphogenesis and analyze the role of Bone morphogenetic protein (Bmp) signaling pathway during this process using zebrafish as animal model. We used the myocardial zebrafish reported line [Tg(myl7:eGFP)twu34] to analyze heart morphogenesis during cardiac looping and combine fluorescence and confocal microscopy techniques with cell signaling pathways inhibition assays. We describe the process of cardiac S-looping morphogenesis in the zebrafish embryo [from 30 to 54 hour post fertilization (hpf)] and establish two parameters for measuring their extension, named: looping angle (alpha) and looping overlap (index a/b). During cardiac looping, Bone morphogenetic protein (Bmp) signaling pathway has a regional patterning which correlates with bending of the nascent heart tube. Upon its pharmacological inhibition (LDN193189 & K02288, both 20 uM from 30 to 54hpf), myocardial cells maintain cuboidal cell shapes and S-shaped bending is impaired showing an increase in the looping angle (LDN193189, alpha=105±20°, n=18, P