Administration of IgG Fc Fragments Prevents Glomerular Injury in Experimental Immune Complex Nephritis

Self Cite

FcR provides a critical link between ligands and effector cells in immune complex diseases. Emerging evidence reveals that angiotensin (Ang)II exerts a wide variety of cellular effects and contributes to the pathogenesis of inflammatory diseases. In anti-glomerular basement membrane Ab-induced glomerulonephritis (GN), we have previously noted that FcR-deficient mice (γ−/−) surviving from lethal initial damage still developed mesangial proliferative GN, which was drastically prevented by an AngII type 1 receptor (AT1) blocker. We further examined the mechanisms by which renin-Ang system (RAS) participates in this immune disease. Using bone marrow chimeras between γ−/− and AT1−/− mice, we found that glomerular injury in γ−/− mice was associated with CD4+ T cell infiltration depending on renal AT1-stimulation. Based on findings in cutaneous delayed-type hypersensitivity, we showed that AngII-activated renal resident cells are responsible for the recruitment of effector T cells. We next examined the chemotactic activity of AngII-stimulated mesangial cells, as potential mechanisms coupling RAS and cellular immunity. Chemotactic activity for T cells and Th1-associated chemokine (IFN-γ-inducible protein-10 and macrophage-inflammatory protein 1α) expression was markedly reduced in mesangial cells from AT1−/− mice. Moreover, this activity was mainly through calcineurin-dependent NF-AT. Although IFN-γ-inducible protein-10 was NF-κB-dependent, macrophage-inflammatory protein 1α was dominantly regulated by NF-AT. Furthermore, AT1-dependent NF-AT activation was observed in injured glomeruli by Southwestern histochemistry. In conclusion, our data indicate that local RAS activation, partly via the local NF-AT pathway, enhances the susceptibility to T cell-mediated injury in anti-glomerular basement membrane Ab-induced GN. This novel mechanism affords a rationale for the use of drugs interfering with RAS in immune renal diseases.

Section: Angii Exerts Proinflammatory Effects In the Kidney Partly Tmentioning

confidence: 55%

Susceptibility to T Cell-Mediated Injury in Immune Complex Disease Is Linked to Local Activation of Renin-Angiotensin System: The Role of NF-AT Pathway

Suzuki

Gómez-Guerrero

Shirato³

et al. 2002

Self Cite

“…These findings are consistent with the demonstrated importance of Fc:FcR-based interactions in previous reports of experimental and spontaneous nephritis (34 -37). Indeed, FcR-targeted therapies have been proposed for modulating immune nephritis (38,39). Anti-GBM Abs planted on the GBM may have the capacity to engage FcR on both the intrinsic glomerulocytes and infiltrating leukocytes.…”

Section: Discussionmentioning

confidence: 99%

Innate Stimuli Accentuate End-Organ Damage by Nephrotoxic Antibodies via Fc Receptor and TLR Stimulation and IL-1/TNF-α Production

Xie

Chen

et al. 2006

Innate stimuli are well recognized as adjuvants of the systemic immune response. However, their role in driving end-organ disease is less well understood. Whereas the passive transfer of glomerular-targeting Abs alone elicited minimal renal disease, the concomitant delivery of innate stimuli triggered severe nephritis, characterized by proliferative glomerulonephritis with crescent formation, and tubulointerstitial disease. Specifically, stimulating TLR2, TLR3, TLR4, and TLR5 by using peptidoglycan, poly(I:C), LPS, and flagellin, respectively, all could facilitate anti-glomerular Ab-elicited nephritis. In this model, innate and immune triggers synergistically activated several cytokines and chemokines, including IL-1, IL-6, TNF-α, and MCP-1, some of which were demonstrated to be absolutely essential for the development of renal disease. Genetic studies revealed that, whereas the innate trigger is dependent on TLR/IL-1R-associated kinase-mediated signaling, the immune component was contingent on FcR-mediated signals. Importantly, infiltrating leukocytes as well as intrinsic glomerular cells may both serve to integrate these diverse signals. Extrapolating to spontaneous immune-mediated nephritis, although the adaptive immune system may be important in generating end-organ targeting Abs, the extent of damage inflicted by these Abs may be heavily dependent on cues from the innate immune system.

“…This would partly explain clinical evidence that bouts of the disease are frequently associated with unspecific upper respiratory tract infection, because cytokines related to common infection, such as IFN-␥, are known to enhance the expression levels of FcR on leukocytes (51). Although systemic blockade of FcR confers beneficial effects in acute IC glomerulonephritis (52), FcR exert physiological effects during the infection. Thus, tissue-specific blockade of the FcRmediated effector mechanism would probably be a better approach for the management of chronic IC diseases.…”

Section: Discussionmentioning

confidence: 99%

Pre-Existing Glomerular Immune Complexes Induce Polymorphonuclear Cell Recruitment Through an Fc Receptor-Dependent Respiratory Burst: Potential Role in the Perpetuation of Immune Nephritis

Suzuki

Gómez-Guerrero

Shirato³

et al. 2003

Self Cite

In immune complex (IC) diseases, FcR are essential molecules facilitating polymorphonuclear cell (PMN) recruitment and effector functions at the IC site. Although FcR-dependent initial tethering and FcR/integrin-dependent PMN accumulation were postulated, their underlying mechanisms remain unclear. We here addressed potential mechanisms involved in PMN recruitment in acute IC glomerulonephritis (nephrotoxic nephritis). Since some renal cells may be recruited from bone marrow (BM) lineages, reconstitution studies with BM chimeras and PMN transfer between wild-type (WT) and FcR-deficient mice (γ−/−) were performed. Severe glomerular damage was induced in WT and Wγ chimeras (BM from WT to irradiated γ−/−), while it was absent in γ−/− and γW chimeras (γ−/− BM to WT). Moreover, WT PMN transfer, but not γ−/− PMN, reconstituted the disease in γ−/−, indicating that FcR on resident cells is not a prerequisite for PMN recruitment in this disease. Surprisingly, transferred WT PMN were recruited coincidentally with NF-κB activation and TNF-α overexpression even in glomeruli with preformed IC (nephrotoxic Ab administered 3 days previously), suggesting that PMN can initially be recruited via its own FcR without previous chemoattractant release. Furthermore, H2O2 inhibition by catalase attenuated the acute WT PMN recruitment and the induction of NF-κB and TNF-α much more than integrin (CD18) blockade, indicating a role for the respiratory burst before integrin-dependent accumulation. In coculture experiments with IC-stimulated PMN and glomeruli, PMN caused acute glomerular TNF-α expression predominantly via FcR-mediated H2O2 production. In conclusion, glomerular IC, even preformed, can cause PMN recruitment and injury through PMN FcR-mediated respiratory burst during initial PMN tethering to IC.