Seminar: Anne Lagendijk

Live-imaging of tension through zebrafish VE-cadherin uncovers mechanical contributions in vascular development and disease

Date:
1 June 2017 10:30 hrs. - 11:30 hrs.
Location:
Figdor Lecture Theatre, 8th floor RIMLS Building, Geert Grooteplein 26-28, route 289
Title:
Live-imaging of tension through zebrafish VE-cadherin uncovers mechanical contributions in vascular development and disease
Speaker(s):

Anne Lagendijk, The University of Queensland, Australia

Host(s):

Leonie Kamminga, Dept. of Molecular Biology, RIMLS

01-06-2017 10:30:0001-06-2017 11:30:00Europe/AmsterdamLive-imaging of tension through zebrafish VE-cadherin uncovers mechanical contributions in vascular development and disease Figdor Lecture Theatre, 8th floor RIMLS Building, Geert Grooteplein 26-28, route 289Rimlsrimls@radboudumc.nl

Remarks / more information:

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It has long been appreciated that physical forces contribute to vasculardevelopment. The quantification of mechanical force and analysis of its conversioninto biochemically relevant information (mechanotransduction) is inherentlychallenging. The recent applications of FRET-based sensors that report tensionthrough adhesive proteins have greatly aided in vitro studies. To visualize andinvestigate adhesive forces in the developing vasculature in vivo, we generated azebrafish VE-cadherin FRET-based Tension Sensor (TS) transgenic strain. We placedthe VE-cadherin-TS module under the control of VE-cadherin’s own regulatoryelements. This resulted in localization at endothelial cell junctions allowing liveimagingof protein and junctional dynamics. VE-cadherin-TS protein is functional andcapable of rescuing two VE-cadherin mutant alleles to adulthood. Furthermore, weshow that quantifiable FRET reflects acto-myosin dependent changes in VE-cadherintension by measuring both ratio-metric FRET and Donor lifetime. During development, we found that arterial maturation involves a progressive decrease intension through VE-cadherin. This maturation profile requires both Vegf growthfactor signaling and the presence of Ca2+.

We further applied the VE-cadherin-TS tool in a zebrafish vascular disease modelthat recapitulates the onset of cerebral cavernous malformations (CCM) in humanpatients. CCM lesions consist of thin-walled endothelial cells that expand out of thevascular wall. These mulberry-shaped lesions (cavernoma) can ultimately ruptureand lead to stroke. We demonstrate that one of the earliest observable defects ofthis disease is reduced tension through VE-cadherin, which likely contributes to thechanges in cellular mechanics that lead to CCM. We are currently correlating thechanges in cell-shape/mechanics to changes in the transcriptome (RNAseq) of CCMcells to identify what drives the initiation of CCM.

Together, our findings show that intra-molecular tension across adhesive proteinscan be imaged with high-resolution in vivo and offers new insights into themechanical processes in vascular development and disease. 



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