Heparin and heparinoids prevent the binding of immune complexes containing nucleosomal antigens to the GBM and delay nephritis in MRL/lpr mice

Abstract

Monoclonal anti-nucleosome antibodies (mAbs) complexed to nucleosomal antigens can bind to DNA and to heparan sulfate (HS) in ELISA and to the GBM in vivo in a rat renal perfusion system, whereas non-complexed mAbs do not bind [1]. In this study, we analyzed whether heparin (HEP) or N-desulfated/acetylated heparins (DSA-HEP), structurally and functionally strongly related to HS, are able to prevent the binding of these complexed mAbs to DNA and to HS in vitro and to rat GBM in vivo. In ELISA the binding of nucleosome complexed antinucleosome antibodies to DNA and HS was inhibited dose-dependently by HEP, DSA-HEP and low molecular weight (LMW) DSA-HEP. Intravenous injection of nucleosome/anti-nucleosome immune complexes without heparin/heparinoids in BALB/c mice led to GBM binding, while simultaneous injection of heparin/heparinoids with complexed antibodies or pretreatment with heparin subcutaneously prior to injection of complexes prevented this binding. Subsequently, we tested the preventive effect of HEP, DSA-HEP and LMW-DSA-HEP on progression of renal disease in MRL/lpr mice. Treatment was started at an age of eight weeks in a dose of 50 micrograms daily. With all three drugs albuminuria was significantly delayed compared to PBS treated controls (cumulative incidence of proteinuria at 20 weeks in controls 60% vs. 13%, 14% and 6% respectively for HEP, DSA-HEP and LMW-DSA-HEP; P < 0.05). At week 21 the glomerulonephritis was histologically less severe in heparin/heparinoid treated animals (P = 0.02). In immunofluorescence the amount of immunoglobulin and C3 deposits in the glomerular capillary wall tended to be less in heparin/heparinoid treated mice compared to PBS treated controls (P = 0.07). Furthermore, at 20 weeks anti-HS levels in plasma of heparin/heparinoid treated mice were significantly lower (P < 0.05). We conclude that interaction of heparin or heparin analogs with HS reactive immune complexes containing nucleosomal antigens prevents the binding of these immune complexes to the GBM and delays nephritis in MRL/lpr mice.

Heparin exerts a dual effect on murine lupus nephritis by enhancing enzymatic chromatin degradation and preventing chromatin binding in glomerular membranes

“…In this study, we investigated in vitro whether heparin had the potential to inhibit binding of chromatin-IgG complexes to glomerular laminins and collagens and whether heparin enhanced enzymatic degradation of chromatin fragments and, with a pilot study in vivo, we investigated whether the effects measured in vitro reflected a beneficial impact on murine lupus nephritis. Earlier studies have shown that heparin/heparinoid treatment has a positive effect on activity of lupus nephritis in MRL-lpr/ lpr mice (39,40). The mechanism(s) for this effect has, however, never been determined, although the anticoagulant effect most likely was not important (40).…”

“…Earlier studies have shown that heparin/heparinoid treatment has a positive effect on activity of lupus nephritis in MRL-lpr/ lpr mice (39,40). The mechanism(s) for this effect has, however, never been determined, although the anticoagulant effect most likely was not important (40).…”

Identification of Tubular Heparan Sulfate as a Docking Platform for the Alternative Complement Component Properdin in Proteinuric Renal Disease

“…It is already known that nonanticoagulant heparins have a beneficial effect on proteinuria and on structural changes in diabetic animals (41,42). In addition, the beneficial effects of these heparinoids on renal tissue, renal outcome, and graft rejection have been studied in several animal models (42)(43)(44)(45)(46)(47). The effects of nonanticoagulant heparins have also been investigated in ischemia-reperfusion, inflammation, and cancer treatment (48 -50).…”

Identification of autoantibody clusters that best predict lupus disease activity using glomerular proteome arrays

“…A significant fraction of the reactivity to α-actinin, myosin, entactin, and aggrecan, for instance, appears to be independent of nuclear antigenic bridges. On the other hand, it remains possible that the observed "direct" binding to these Ags is mediated, at least in part, by anti-DNA Abs that are crossreactive to these other Ags, as has been demonstrated previously with a couple of glomerular Ags (22)(23)(24)(25)(26)(27)(28)(29). It will be important to firmly establish the extent to which reactivity to these glomerular Ags is mediated by crossreactive anti-DNA Abs in future studies.…”

“…(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). In some instances, these antiglomerular reactivities have been demonstrated to be dependent upon nuclear Ag bridges, whereas in other studies, the nephrophilic Abs have been shown to be anti-DNA Abs with direct crossreactive potential to glomerular Ags (3,9,(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). In addition, antiglomerular Abs that were not DNA reactive have also been documented in murine and human lupus nephritis (32,33).…”