The luminal surfaces of endothelial cells (ECs) that line our vasculature are coated with a glycocalyx of membrane-bound macromolecules comprised of sulfated proteoglycans, hyaluronic acid, sialic acids, glycocproteins and plasma proteins that adhere to this surface matrix. The endothelial glycocalyx layer (EGL) provides a multifunctional coating to the vasculature that is degraded in disease states such as atherosclerosis and diabetes. Because of dehydration artifacts associated with conventional electron microscopy, even such rudimentary characteristics as the thickness of the layer have not been firmly established. In vivo and in vitro studies have, however, shown that heparan sulfate proteoglycans mediate endothelial remodeling (cell elongation and alignment) in response to fluid shear stress and along with hyaluronic acid control vital mechanotransduction events such as fluid shear-induced stimulation of nitric oxide production, but the core proteins that are involved in these characteristic responses are not known. To address these fundamental questions that are crucial for our understanding of vascular function in health and disease, we will pursue the following studies in the proposed research: To elucidate the structure of the endothelial glycocalyx layer (EGL) we will apply, for the first time, cryo-transmission electron microscopy (cryo-TEM) in conjunction with confocal microscopy to determine its thickness and organization. To determine the proteoglycan core proteins that mediate EC remodeling and mechanotransduction in response to fluid shear stress we will use glycosaminoglycan (GAG) degrading enzymes, RNA interference technology and adhesion blocking amino acid sequences in vitro and knockout animals in vivo to deconstruct these processes. To carry out the projects in this Bioengineering Research Grant (BRG), we have organized a research team with core expertise in bioengineering including: in vitro shear experiments (Tarbell), and in vivo shear experiments (Fu) that is complemented by expertise in microscopy and molecular biology (Spray).

Public Health Relevance

The research is important to public health because the endothelial glycocalyx layer (EGL) provides a multifunctional coating to the vasculature that is degraded in disease states such as atherosclerosis and diabetes. Degradation of the EGL leads to vasoregulatory dysfunction through, for example, loss of blood flow-induced stimulation of the potent vasodilator, nitric oxide. Knowledge of EGL structure and the core proteins and glycosaminoglycans involved in mechanotransduction/remodeling will be required if methods are to be developed to re-constitute or reinforce the EGL. A re-constituted EGL will restore critical vasoregulatory functions, thus combating disease. The foundational work proposed in this application is essential for translational work that will follow as part of the long range goals of this project.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL094889-03
Application #
8247713
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
Reid, Diane M
Project Start
2010-04-15
Project End
2014-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
3
Fiscal Year
2012
Total Cost
$621,021
Indirect Cost
$154,921
Name
City College of New York
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
603503991
City
New York
State
NY
Country
United States
Zip Code
10031
Cancel, Limary M; Ebong, Eno E; Mensah, Solomon et al. (2016) Endothelial glycocalyx, apoptosis and inflammation in an atherosclerotic mouse model. Atherosclerosis 252:136-46
Zullo, Joseph A; Fan, Jie; Azar, Tala T et al. (2016) Exocytosis of Endothelial Lysosome-Related Organelles Hair-Triggers a Patchy Loss of Glycocalyx at the Onset of Sepsis. Am J Pathol 186:248-58
Zhang, Lin; Zeng, Min; Fan, Jie et al. (2016) Sphingosine-1-phosphate Maintains Normal Vascular Permeability by Preserving Endothelial Surface Glycocalyx in Intact Microvessels. Microcirculation 23:301-10
Yen, Wanyi; Cai, Bin; Yang, Jinlin et al. (2015) Endothelial surface glycocalyx can regulate flow-induced nitric oxide production in microvessels in vivo. PLoS One 10:e0117133
Tarbell, John M; Simon, Scott I; Curry, Fitz-Roy E (2014) Mechanosensing at the vascular interface. Annu Rev Biomed Eng 16:505-32
Dabagh, Mahsa; Jalali, Payman; Butler, Peter J et al. (2014) Shear-induced force transmission in a multicomponent, multicell model of the endothelium. J R Soc Interface 11:20140431
Tarbell, John M; Shi, Zhong-Dong; Dunn, Jessilyn et al. (2014) Fluid Mechanics, Arterial Disease, and Gene Expression. Annu Rev Fluid Mech 46:591-614
Zeng, Ye; Tarbell, John M (2014) The adaptive remodeling of endothelial glycocalyx in response to fluid shear stress. PLoS One 9:e86249
Zeng, Ye; Adamson, Roger H; Curry, Fitz-Roy E et al. (2014) Sphingosine-1-phosphate protects endothelial glycocalyx by inhibiting syndecan-1 shedding. Am J Physiol Heart Circ Physiol 306:H363-72
Ebong, Eno E; Lopez-Quintero, Sandra V; Rizzo, Victor et al. (2014) Shear-induced endothelial NOS activation and remodeling via heparan sulfate, glypican-1, and syndecan-1. Integr Biol (Camb) 6:338-47

Showing the most recent 10 out of 24 publications