Inactivation of heparan sulfate 2-O-sulfotransferase accentuates neutrophil infiltration during acute inflammation in mice

Abstract

Neutrophil recruitment and extravasation at sites of inflammation provide a mechanism for host defense. We showed previously that heparan sulfate, a type of sulfated glycosaminoglycan, facilitates neutrophil recruitment based on the reduction of neutrophil infiltration in mice in which the overall sulfation of the chains was reduced by selective inactivation of IntroductionThe inflammatory response, initiated by injury or infection, begins by release of cytokines, such as TNF-␣ and IL-1, from resident macrophages. These effectors stimulate endothelial cells, resulting in the secretion of von Willebrand factor, which aids in platelet recruitment and thrombus formation, and the rapid appearance of P-selectin on the apical (lumenal) face of endothelial cells. P-selectin interacts with its primary ligand, P-selectin glycoprotein ligand-1 expressed on neutrophils, enabling rolling of the cells under blood flow. Chemokines released by resident inflammatory and stromal cells transcytose across the endothelium and bind to the apical surface. Their presentation to rolling leukocytes then activates G-protein-coupled receptors, which in turn activates integrins and causes firm adhesion of the leukocytes to the endothelium. Changes in cell shape and spreading occur followed by transcellular and paracellular extravasation. After entry into tissues, neutrophils release proteases and reactive oxygen species that kill foreign pathogens and prepare the tissue for repair.A large body of evidence suggests the importance of heparan sulfate in inflammation. Cytokines (TNF-␣, IL-1, and others), Land P-selectins, and chemokines bind to therapeutic heparin and purified heparan sulfate. Furthermore, heparin blocks L-and P-selectin in vivo in mice, 1,2 which may explain in part its anti-inflammatory activity in humans. 3 Recently, we showed that mice bearing an endothelial-specific mutation of the biosynthetic enzyme, N-acetylglucosamine N-deacetylase-N-sulfotransferase-1 (Ndst1) exhibit reduced neutrophil extravasation in vivo in several acute inflammatory models. 4 Decreased neutrophil infiltration was partially the result of enhanced rolling velocity in vitro, which correlated with weaker binding of L-selectin to endothelial cells. Inactivation of Ndst1 also resulted in reduced chemokine transcytosis across endothelial cells and reduced presentation on the cell surface. Ndst1-deficient mice exhibit decreased allergen-induced airway hyper-responsiveness and inflammation characterized by a significant reduction in airway recruitment of inflammatory cells (eosinophils, macrophages, neutrophils, and lymphocytes). 5 Heparan sulfate has a complex structure, consisting of variably sulfated disaccharides arranged in clusters, which make up the binding sites for ligands. 6 Ndst1 and other Ndst isoforms catalyze the initial sulfation of subsets of glucosamine residues, creating the substrates for 2-O-sulfation of adjacent uronic acid residues and 6-O-sulfation (and more rarely 3-O-sulfation) of N-sulfoglucosamine units. 7 Thus, inactivation of...

A microscopic view on the renal endothelial glycocalyx

“…Again, this binding may be modified by chemical editing of HS chains. For example, changing the domain structure of HS by inactivation of Hs2st (which causes a compensatory increase in glucosamine N-sulfation and 6-Osulfation) results in enhanced binding of IL-8 to the endothelium and increases inflammation (5).…”

Sonic hedgehog processing and release are regulated by glypican heparan sulfate proteoglycans

“…The assembly of heparan sulfate in these and other cells is not template driven; rather, it is thought to depend on the organization and specificity of biosynthetic enzymes and the availability of precursors. Thus, 2-O sulfotransferase deficiency not only reduces heparan sulfate 2-O-sulfation, but also strongly enhances N-sulfation and moderately elevates 6-Osulfation by an unknown compensatory mechanism (Axelsson et al, 2012). These secondary biosynthetic effects lead to complex changes in the heparan sulfate domain structure and overall heparan sulfate sulfation in these cells.…”

Heparan Sulfate Modulates Neutrophil and Endothelial Function in Antibacterial Innate Immunity

“…Analysis of these animals revealed that neutrophil-derived HS plays a significant role in controlling bactericidal activity. Whereas inactivation of Hs2st on endothelial cells facilitates neutrophil infiltration to sterile inflammatory stimuli (11), the impaired intrinsic bactericidal activity of Hs2st-deficient neutrophils results in increased susceptibility of Hs2st-deficient mice to invasive bacterial infection. The bactericidal defect in Hs2st-deficient mice correlates with reduced NET formation and altered histone affinity to HS within the NETs.…”

“…HS modulates the rapid recruitment of neutrophils to sites of infection or injury at different levels, in particular through its interactions with cytokines, chemokines, and selectins (8). We reported previously that reduced expression and altered sulfation of HS on endothelial cells, achieved by inactivating glucosamine N-deacetylase-N-sulfotransferase-1 (Ndst1) or uronyl 2-O-sulfotransferase (Hs2st), altered neutrophil extravasation to sites of sterile inflammation by modifying interactions between endothelial HS and L-selectins on neutrophils and chemokines released during the inflammatory response (11,12). In contrast, the same modifications of HS on the neutrophil cell surface did not affect trafficking during sterile inflammation (11,12) and had only mild effects on the acquired immune responses (13).…”

“…We reported previously that reduced expression and altered sulfation of HS on endothelial cells, achieved by inactivating glucosamine N-deacetylase-N-sulfotransferase-1 (Ndst1) or uronyl 2-O-sulfotransferase (Hs2st), altered neutrophil extravasation to sites of sterile inflammation by modifying interactions between endothelial HS and L-selectins on neutrophils and chemokines released during the inflammatory response (11,12). In contrast, the same modifications of HS on the neutrophil cell surface did not affect trafficking during sterile inflammation (11,12) and had only mild effects on the acquired immune responses (13). Here we extended this line of investigation to live-bacterial-infection models to probe how HS modification can influence intrinsic neutrophil functions relevant to antibacterial defense and microbicidal activity.…”