Abstract
The recruitment of leukocytes, mediated by endothelium bound chemokine gradients, is a vital process in inflammation. The highly negatively charged, unbranched polysaccharide family of glycosaminoglycans (GAGs), such as heparan sulfate and chondroitin sulfate mediate chemokine immobilization. Specifically the binding of CXCL8 (interleukin 8) to GAGs on endothelial cell surfaces is known to regulate neutrophil recruitment. Currently, it is not clear if binding of CXCL8 to GAGs leads to endothelial downstream signaling in addition to the typical CXCR1/CXCR2 (C-X-C motif chemokine receptor 1 and 2)-mediated signaling which activates neutrophils. Here we have investigated the changes in protein expression of human microvascular endothelial cells induced by CXCL8. Tumor necrosis factor alpha (TNFα) stimulation was used to mimic an inflammatory state which allowed us to identify syndecan-4 (SDC4) as the potential proteoglycan co-receptor of CXCL8 by gene array, real-time PCR and flow cytometry experiments. Enzymatic GAG depolymerization via heparinase III and chondroitinase ABC was used to emulate the effect of glycocalyx remodeling on CXCL8-induced endothelial downstream signaling. Proteomic analyses showed changes in the expression pattern of a number of endothelial proteins such as Zyxin and Caldesmon involved in cytoskeletal organization, cell adhesion and cell mobility. These results demonstrate for the first time a potential role of GAG-mediated endothelial downstream signaling in addition to the well-known CXCL8-CXCR1/CXCR2 signaling pathways in neutrophils.
Highlights
The interaction between leukocytes and the endothelial cell surface is a key event in inflammatory processes
These results demonstrate for the first time a potential role of GAG-mediated endothelial downstream signaling in addition to the well-known CXCL8-CXCR1/CXCR2 signaling pathways in neutrophils
Glycosaminoglycans (GAG) at the endothelial cell surface are crucial mediators of this interaction [1]. This family of unbranched polysaccharides is found on all human cells as well as in the extracellular matrix and it consists of six different members, heparin (HP), heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), keratan sulfate (KS) and hyaluronic acid (HA), which differ in their disaccharide building blocks
Summary
The interaction between leukocytes and the endothelial cell surface is a key event in inflammatory processes. GAG-protein interaction can lead to protection against proteolysis [28,29], mediation and changes in protein–protein interactions [30,31,32,33] and protein presentation on the endothelial cell surface [34,35]. This chemokine is involved in numerous pathophysiological conditions including cancer [36], chronic obstructive pulmonary disease (COPD) [37] and rheumatoid diseases [38] It is a well-known GAG-binding protein that is responsible for the recruitment of neutrophils to the site of inflammation by activating the chemokine receptors CXCR1 and CXCR2 [39]. Zyxin contains an Ena/VASP binding domain that is crucial for actin dynamics [67] Together with caldesmon this protein influences integrin mediated actrin stress fiber formation [68]. See Supplemental Material for a complete list of all changes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
