Development of a tool to probe the biomechanical properties of the endothelial surface layer

Introduction: We have recently found in isolated human umbilical vein endothelial cells (HUVEC) that turbulent (atheroprone) vascular shear stress (VSS) down regulates endothelial connexin 40 and up regulates C6- and V1-type transient receptor potential (TRP) channels. However the mechanism for these atheroprone changes is poorly understood. We have shown that atheroprone VSS profile down regulates the synthesis of a major component of the endothelial surface layer (ESL), hyaluronan (HA). These findings together with the extensive amount of publications showing the importance of ESL in endothelial VSS sensation led us to speculate, that HA might be part of an atheroprone circulus vitiosus: in the absence of atheroprotective VSS, HA expression decreases. This leads to decrease of vascular VSS sensitivity followed by further reduction of HA expression. Thus we aimed at developing a tool to probe the properties and thickness of the surface layer of cultured HUVECs to allow investigation the role of HA for VSS related alterations of the ESL. Methods: A defocus imaging based single particle tracking application was developed. It allows tracking the 3D position of fluorescent nanobeads with a precision beyond the diffraction resolution limit. Local viscosity can be assessed by quantifying the nanobeads’ Brownian motion. Results and conclusion: For a vertical range of 4.5 µm, the validity of vertical single particle tracking was 16 nm, with a precision of about 5 nm. In the horizontal plane precision was 5 nm. In first experiments with HUVEC we could show an increase of local viscosity in a region close to the cell surface with a thickness of about 1000 nm which may correspond to the ESL. Thus, the established approach has the potential to study biophysical properties of the ESL, including thickness and viscosity. This should allow to investigate the alteration of ESL beside different pathological conditions.

Author dc:creator

• Marki, Alex

• endothel
• glycocalyx
• viscosity
• microscopy
• superresolution

Licence dc:rights.uri

• http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen

Language dc:language

eng

Identifier URI

http://dx.doi.org/10.17169/refubium-15439

OAI record oai:identifier

https://refubium.fu-berlin.de/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Arefubium.fu-berlin.de%3Afub188%2F11241