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Updated: Sep 29, 2025
Mechanical Vessel Injury in Zebrafish Embryos
Published on: February 17, 2015
In vivo dissection of Rhoa function in vascular development using zebrafish
Laura M Pillay1, Joseph J Yano1,2, Andrew E Davis1
1Division of Developmental Biology, National Institute of Child Health and Human Development, National Institutes of Health, 6 Center Dr. Bethesda, Bethesda, MD, 20892, USA.
Abstract:
The small monomeric GTPase RHOA acts as a master regulator of signal transduction cascades by activating effectors of cellular signaling, including the Rho-associated protein kinases ROCK1/2. Previous in vitro cell culture studies suggest that RHOA can regulate many critical aspects of vascular endothelial cell (EC) biology, including focal adhesion, stress fiber formation, and angiogenesis. However, the specific in vivo roles of RHOA during vascular development and homeostasis are still not well understood. In this study, we examine the in vivo functions of RHOA in regulating vascular development and integrity in zebrafish. We use zebrafish RHOA-ortholog (rhoaa) mutants, transgenic embryos expressing wild type, dominant negative, or constitutively active forms of rhoaa in ECs, pharmacological inhibitors of RHOA and ROCK1/2, and Rock1 and Rock2a/b dgRNP-injected zebrafish embryos to study the in vivo consequences of RHOA gain- and loss-of-function in the vascular endothelium. Our findings document roles for RHOA in vascular integrity, developmental angiogenesis, and vascular morphogenesis in vivo, showing that either too much or too little RHOA activity leads to vascular dysfunction.
Insights
The small GTPase RHOA regulates vascular development and integrity. Both excessive and insufficient RHOA activity impair blood vessel formation and function in zebrafish, highlighting its critical role in vascular health.
Area of Science:
- Molecular Biology
- Developmental Biology
- Cell Biology
Background:
- The small monomeric GTPase RHOA is a key regulator of cellular signaling pathways.
- In vitro studies suggest RHOA influences endothelial cell (EC) functions like focal adhesion, stress fiber formation, and angiogenesis.
- The in vivo roles of RHOA in vascular development and homeostasis remain largely unclear.
Purpose of the Study:
- To investigate the in vivo functions of RHOA in regulating vascular development and integrity.
- To elucidate the consequences of RHOA gain- and loss-of-function in the vascular endothelium.
Main Methods:
- Utilized zebrafish RHOA-ortholog (rhoaa) mutants and transgenic embryos.
- Employed pharmacological inhibitors of RHOA and ROCK1/2.
- Used dgRNP injection to disrupt Rock1 and Rock2a/b function in zebrafish embryos.
Main Results:
- Demonstrated RHOA's essential role in maintaining vascular integrity in vivo.
- Showcased RHOA's involvement in developmental angiogenesis and vascular morphogenesis.
- Found that both excessive and deficient RHOA activity result in vascular dysfunction.
Conclusions:
- RHOA is a critical regulator of vascular development and integrity in vivo.
- Proper RHOA activity levels are crucial for normal vascular function.
- Dysregulation of RHOA impacts angiogenesis and vascular morphogenesis.
