Blocking of inflammatory heparan sulfate domains by specific antibodies is not protective in experimental glomerulonephritis.

Jasper J Van Gemst,Toin H Van Kuppevelt,Jo H Berden,Johan Van Der Vlag,Bart Smeets,Angelique L W M M Rops,Nathalie J H G Passmann,Ton J Rabelink,Markus A Loeven

doi:10.1371/journal.pone.0261722

Abstract

Glomerulonephritis is an acquired serious glomerular disease, which involves the interplay of many factors such as cytokines, chemokines, inflammatory cells, and heparan sulfate (HS). We previously showed that blocking of inflammatory heparan sulfate domains on cultured glomerular endothelium by specific anti-HS single chain antibodies reduced polymorphonuclear cell (PMN) adhesion and chemokine binding. We hypothesized that injection of anti-HS antibodies in PMN-driven experimental glomerulonephritis should reduce glomerular influx of PMNs and thereby lead to a better renal outcome. In contrast to our hypothesis, co-injection of anti-HS antibodies did not alter the final outcome of anti-glomerular basement membrane (anti-GBM)-induced glomerulonephritis. Glomerular PMN influx, normally peaking 2 hours after induction of glomerulonephritis with anti-GBM IgG was not reduced by co-injection of anti-HS antibodies. Four days after induction of glomerulonephritis, albuminuria, renal function, glomerular hyalinosis and fibrin deposition were similar in mice treated and not treated with anti-HS antibodies. Interestingly, we observed transient effects in mice co-injected with anti-HS antibodies compared to mice that did not receive anti-HS antibodies: (i) a decreased renal function 2 hours and 1 day after induction of glomerulonephritis; (ii) an increased albuminuria after 2 hours and 1 day; (iii) an increased glomerular fibrin deposition after 1 day; (iv) a reduced glomerular macrophage influx after 1 day; (v) a sustained glomerular presence of PMNs at day 1 and 4, accompanied by an increased renal expression of IL-6, CXCL1, ICAM-1, L-selectin, CD11b and NF-κB. The mechanism underlying these observations induced by anti-HS antibodies remains unclear, but may be explained by a temporarily altered glycocalyx and/or altered function of PMNs due to the binding of anti-HS antibodies. Nevertheless, the evaluated anti-HS antibodies do not show therapeutic potential in anti-GBM-induced glomerulonephritis. Future research should evaluate other strategies to target HS domains involved in inflammatory processes during glomerulonephritis.

Highlights

Glomerular diseases can lead to end stage renal disease and thereby require renal replacement therapy such as dialysis or transplantation [1]
The autologous phase is starting around day 4, in which newly developed mouse anti-rabbit IgG contribute to the disease as well, the severity of disease is driven by the initial glomerular influx of polymorphonuclear cell (PMN)
We first addressed whether the anti-heparan sulfate (HS) antibodies specific for inflammatory HS domains reached the glomerular compartment after injection

Summary

Introduction

Glomerular diseases can lead to end stage renal disease and thereby require renal replacement therapy such as dialysis or transplantation [1]. Leukocyte migration towards the site of inflammation involves the concerted action of cytokines, chemokines, adhesion molecules and glycosaminoglycans (GAGs) [6,7,8,9]. A disturbed/diseased glycocalyx contributes to proteinuria, chemokine binding and leukocyte trafficking since the sequential steps of leucocyte migration and adhesion to sites of inflammation are mediated by the glomerular endothelial glycocalyx [1, 7,8,9,10,11,12]. The heterogeneous nature of HS allows the formation of specific binding sites for various ligands, including chemokines and cell adhesion molecules such as integrins and selectins [6, 8,9,10, 14]. HS seems to be the main GAG mediating endothelial cell-chemokine and leukocyte interactions

Methods

Results

Conclusion