Targeting the Glycocalyx to Prevent Endothelial Dysfunction

Introduction: Endothelial dysfunction underlies atherosclerosis and affects outcomes in trauma-related hemorrhage and major vascular surgery. It may be fostered by an impairment of the glycocalyx, all glycan-carrying cell membrane structures, caused by disturbed blood flow and inflammatory stimuli. Biomarkers for glycocalyx integrity and treatment strategies for its stabilization have not been implemented in clinical practice.

Methods: We will analyze the alterations of the endothelial glycocalyx under stress by means of bulk RNA sequencing, super-resolution microscopy, and liquid chromatography. We will then modify the glycans by enzymatic degradation and gene knockdown, and measure changes in endothelial gene expression. Furthermore, we will generate artificially disturbed blood flow by partial ligation of the carotid artery in mice and perform single-cell RNA sequencing and structural analyses of endothelial glycans. Ultimately, we aim to stabilize the glycocalyx by use of small molecules targeting glycan-modifying enzymes and covalent attachment of glycan fragments by bioorthogonal reactions.

Results: We could already show that gene expression of human aortic endothelial cells under flow depends on the magnitude and direction of the shear stress. While the anti-inflammatory transcription factor KLF2 and endothelial nitric oxide synthase (ENOS) are upregulated under high laminar flow, vascular adhesion molecule 1 (VCAM1) and the chemokine MCP1 are downregulated. These effects are attenuated by shear stress reduction and flow reversal. Whether this differential expression of mechanosensitive genes is mediated by the glycocalyx will be determined.

Conclusion: Stabilizing the glycocalyx may preserve endothelial function and lead the way towards novel therapeutics to prevent atherosclerosis and improve surgical outcomes.