CEP41-mediated ciliary tubulin glutamylation drives angiogenesis through AURKA-dependent deciliation.

Soo Mi Ki,Byung‐Ok Choi,Eui‐Ju Choi,Ki Wha Chung,Young‐Ki Bae,Boyoun Park,Ji Hyun Kim,Ji Eun Lee,So Yeon Won,Shin Ji Oh,In Young Lee

doi:10.15252/embr.201948290

Abstract

The endothelial cilium is a microtubule‐based organelle responsible for blood flow‐induced mechanosensation and signal transduction during angiogenesis. The precise function and mechanisms by which ciliary mechanosensation occurs, however, are poorly understood. Although posttranslational modifications (PTMs) of cytoplasmic tubulin are known to be important in angiogenesis, the specific roles of ciliary tubulin PTMs play remain unclear. Here, we report that loss of centrosomal protein 41 (CEP41) results in vascular impairment in human cell lines and zebrafish, implying a previously unknown pro‐angiogenic role for CEP41. We show that proper control of tubulin glutamylation by CEP41 is necessary for cilia disassembly and that is involved in endothelial cell (EC) dynamics such as migration and tubulogenesis. We show that in ECs responding to shear stress or hypoxia, CEP41 activates Aurora kinase A (AURKA) and upregulates expression of VEGFA and VEGFR2 through ciliary tubulin glutamylation, as well as leads to the deciliation. We further show that in hypoxia‐induced angiogenesis, CEP41 is responsible for the activation of HIF1α to trigger the AURKA‐VEGF pathway. Overall, our results suggest the CEP41‐HIF1α‐AURKA‐VEGF axis as a key molecular mechanism of angiogenesis and demonstrate how important ciliary tubulin glutamylation is in mechanosense‐responded EC dynamics.

Highlights

The endothelial cilium is a microtubule-based organelle responsible for blood flow-induced mechanosensation and signal transduction during angiogenesis
We further demonstrate that centrosomal protein 41 (CEP41) binds hypoxia-inducible factor 1-alpha (HIF1a) and their physical interaction is required for the activation of Aurora kinase A (AURKA) and its resulting regulation of endothelial cell (EC) dynamics during angiogenesis
To determine whether CEP41 plays a role in angiogenesis, we examined the effect of CEP41 depletion on EC behavior using validated CEP41 siRNAs (Appendix Fig S1) in human umbilical vein endothelial cells (HUVECs)

Summary

Introduction

The endothelial cilium is a microtubule-based organelle responsible for blood flow-induced mechanosensation and signal transduction during angiogenesis. We show that proper control of tubulin glutamylation by CEP41 is necessary for cilia disassembly and that is involved in endothelial cell (EC) dynamics such as migration and tubulogenesis. Our results suggest the CEP41HIF1a-AURKA-VEGF axis as a key molecular mechanism of angiogenesis and demonstrate how important ciliary tubulin glutamylation is in mechanosense-responded EC dynamics. Upon activation by angiogenic signals, ECs in pre-existing vessels sprout new branches with directional specificity to extend the vascular network. During angiogenic branching, migrating ECs in a sprout are morphologically polarized to facilitate directional migration This process is tightly regulated by microtubules [3]. The cell polarization and migration events that occur in its earliest branching stages require the structural and functional framework provided by the EC microtubule network [5,6,7]. Our results reveal the mechanism by which EC deciliation induced by mechanosensation facilitates the expression of pro-angiogenic regulators

Results

Ac-Tub

D Ctrl MO

Discussion

Materials and Methods