Salas-Vidal, E. | Search bioRxiv

bioRxiv2024

Epiboly in zebrafish requires reactive oxygen species produced by NADPH oxidases for the regulation of vesicular trafficking

Epiboly is the first morphogenetic cell movement that occurs at the onset of gastrulation in zebrafish. During epiboly, the blastoderm thins out and spreads cells over the massive yolk cell. Epiboly progression is controlled by a complex regulatory network that involves diverse molecular effectors. Previously, we reported that reactive oxygen species (ROS) derived from NADPH oxidases (Nox) are required for normal epiboly progression, embryo survival, and early development. We also found that the inhibition of Nox activity during gastrulation downregulates E-cadherin abundance at the enveloping layer (EVL) cell margins. Since the dynamic localization of E-cadherin at the plasma membrane is highly regulated by endocytosis and vesicular trafficking during epiboly, in the present study, we investigated the effects of Nox inhibition and hydrogen peroxide (H2O2) on endocytosis and in the localization of different proteins important for endosomal trafficking in zebrafish embryos. We show that the simultaneous treatment with the Nox inhibitor VAS2870 and the dynamin 2 (Dnm2) inhibitor dynasore rescues the effects of VAS2870 on epiboly delay, embryo mortality and E-cadherin abundance at EVL cell margins. Furthermore, we found that H2O2 impacts the endocytic rate of fluorescent fluid-phase markers at the EVL, as well as the localization and abundance of Rab11, a small GTPase protein involved in recycling endosomes. Our results suggest that Nox-derived ROS participate in the regulation of the initial steps of endocytosis and in the endosomal trafficking required for epiboly progression during early zebrafish development. HIGHLIGHTS- NADPH oxidase (Nox) activity is required for the epiboly and localization of E- cadherin. - Dynamin inhibition rescues the developmental defects produced by the loss of Nox activity. - Nox-derived reactive oxygen species (ROS) participate in the regulation of endosome and E-cadherin trafficking, which is required for epiboly. - Nox inhibition increases the rate of fluorescent fluid-phase markers of endocytosis in EVL cells. - H2O2 decreases fluid-phase internalization in EVL cells. - H2O2 regulates Rab11 localization

developmental biology↗

bioRxiv2023

Epiboly in zebrafish requires the coordinated activity of NADPH oxidases and dynamin.

Withdrawal statementThe authors have withdrawn their manuscript owing to significant errors in figures 1, 3, 6, and supplementary figure 3. Also, because some of the results were incorrectly reported. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

developmental biology↗

bioRxiv2020

Multi-organ transcriptomic landscape of Ambystoma velasci metamorphosis

Metamorphosis is a postembryonic developmental process that involves morphophysiological and behavioral changes, allowing organisms to adapt into a novel environment. In some amphibians, aquatic organisms undergo metamorphosis to adapt in a terrestrial environment. These organisms experience major changes in their circulatory, respiratory, digestive, excretory and reproductive systems. We performed a transcriptional global analysis of heart, lung and gills during diverse stages of Ambystoma velasci metamorphosis. In our analyses, we identified eight gene clusters for each organ, according to the expression patterns of differentially expressed genes. We found 4,064 differentially expressed genes in the heart, 4,107 in the lung and 8,265 in the gills. Among the differentially expressed genes in the heart, we observed genes involved in the differentiation of cardiomyocytes in the interatrial zone, vasculogenesis and in the maturation of coronary vessels. In the lung, we found genes differentially expressed related to angiogenesis, alveolarization and synthesis of the surfactant protein. In the case of the gills, the most prominent biological processes identified are degradation of extracellular matrix, apoptosis and keratin production. Our study sheds light on the transcriptional responses and the pathways involved in the transformation of the facultative metamorphic salamander A. velasci in an organ-specific manner.

developmental biology↗