The Th17 immune response appears to contribute to the pathogenesis of human and experimental crescentic GN, but the cell types that produce IL-17A in the kidney, the mechanisms involved in its ...induction, and the IL-17A-mediated effector functions that promote renal tissue injury are incompletely understood. Here, using a murine model of crescentic GN, we found that CD4(+) T cells, γδ T cells, and a population of CD3(+)CD4(-)CD8(-)γδT cell receptor(-)NK1.1(-) T cells all produce IL-17A in the kidney. A time course analysis identified γδ T cells as a major source of IL-17A in the early phase of disease, before the first CD4(+) Th17 cells arrived. The production of IL-17A by renal γδ T cells depended on IL-23p19 signaling and retinoic acid-related orphan receptor-γt but not on IL-1β or IL-6. In addition, depletion of dendritic cells, which produce IL-23 in the kidney, reduced IL-17A production by renal γδ T cells. Furthermore, the lack of IL-17A production in γδ T cells, as well as the absence of all γδ T cells, reduced neutrophil recruitment into the kidney and ameliorated renal injury. Taken together, these data suggest that γδ T cells produce IL-17A in the kidney, induced by IL-23, promoting neutrophil recruitment, and contributing to the immunopathogenesis of crescentic GN.
Systemic lupus erythematosus (SLE) is a common autoimmune disorder with a complex and poorly understood immuno-pathogenesis. Lupus nephritis (LN) is a frequent and difficult to treat complication, ...which causes high morbidity and mortality. The multifunctional cytokine amphiregulin (AREG) has been implicated in SLE pathogenesis, but its function in LN currently remains unknown. We thus studied the model of pristane-induced LN and found increasing renal and systemic AREG expression during the course of disease. Importantly, renal injury was significantly aggravated in the absence of AREG, revealing a net anti-inflammatory role. Analyses of immune responses showed dual effects. On the one hand, AREG enhanced activation of pro-inflammatory myeloid cells, which however did not play a major role for the course of LN. More importantly, on the other hand, AREG strongly suppressed pathogenic cytokine production by T helper effector cells. This effect was more general in nature and could be reproduced in response to antigen immunization. Since AREG has been postulated to downregulate T cell responses via enhancing Treg suppressive capacity, we followed up on this aspect. Interestingly, however, in vitro studies revealed potential direct and Treg independent effects of AREG on T helper effector cells. In favor of this notion, we found significantly enhanced T cell responses and consecutive aggravation of LN, only if epidermal growth factor receptor (EGFR) signaling was abrogated in total T cells, but not if the EGFR was absent on Tregs alone. Finally, we also found enhanced AREG expression in plasma and renal biopsies of patients with LN, supporting the relevance of our findings for human disease. In summary, our data identify AREG as an anti-inflammatory mediator of LN via broad downregulation of pathogenic T cell immunity. These findings further highlight the AREG/EGFR axis as a potential therapeutic target.
•Amphiregulin (AREG) is overexpressed in murine and human lupus nephritis (LN).•AREG activates pro-inflammatory monocytes/macrophages.•AREG potently downregulates pathogenic CD4+ T cell responses.•The resulting sum effect of AREG in LN is anti-inflammatory and reno-protective.•AREG‘s effects are partly mediated via direct and Treg independent interaction with T helper effector cells.
Aims
Renal involvement in anti‐neutrophil cytoplasmic antibody (ANCA)‐associated vasculitis contributes to significant morbidity and mortality in patients. In chronic inflammation, B cells are ...recruited to the inflamed tissue and organised lymphoid structures have been described in several autoimmune diseases. The aim of this study was to correlate the lymphoid organisation in renal biopsies with renal outcome in ANCA‐associated glomerulonephritis (GN).
Methods and results
We investigated 112 renal biopsies from patients with newly diagnosed ANCA‐associated necrotising GN. We identified four different levels of the intrarenal organisation of lymphocytes: T cells without B cells, scattered B and T cells, clustered lymphocytic infiltrates and nodular compartmentally arranged B and T cell aggregates. Almost half the patients showed clusters of B and T lymphocytes in their biopsies. In 15 of these biopsies, a higher degree of organisation with lymphocytic compartments was detected. Inflammatory cell organisation was associated with renal failure, but not with tubular atrophy and interstitial fibrosis. Patients with organised lymphocytic infiltrates in their biopsy had worse renal function during follow‐up and were more likely to develop end stage renal disease.
Conclusions
In the present study, we show that the renal lymphocytic organisation is associated with renal outcome in ANCA‐associated GN. The organisation of the lymphocytic infiltrate may be a morphological correlate of a perpetual and exaggerated inflammation in renal ANCA disease. Classifying the lymphocytic infiltrate could help to predict renal outcome, and might therefore be used for individualised adjustments in the intensity and duration of immunosuppressive therapy.
The ability of CD4(+) T cells to differentiate into pathogenic Th1 and Th17 or protective T regulatory cells plays a pivotal role in the pathogenesis of autoimmune diseases. Recent data suggest that ...CD4(+) T cell subsets display a considerable plasticity. This plasticity seems to be a critical factor for their pathogenicity, but also for the potential transition of pathogenic effector T cells toward a more tolerogenic phenotype. The aim of the current study was to analyze the plasticity of Th17 cells in a mouse model of acute crescentic glomerulonephritis and in a mouse chronic model of lupus nephritis. By transferring in vitro generated, highly purified Th17 cells and by using IL-17A fate reporter mice, we demonstrate that Th17 cells fail to acquire substantial expression of the Th1 and Th2 signature cytokines IFN-γ and IL-13, respectively, or the T regulatory transcription factor Foxp3 throughout the course of renal inflammation. In an attempt to therapeutically break the stability of the Th17 phenotype in acute glomerulonephritis, we subjected nephritic mice to CD3-specific Ab treatment. Indeed, this treatment induced an immunoregulatory phenotype in Th17 cells, which was marked by high expression of IL-10 and attenuated renal tissue damage in acute glomerulonephritis. In summary, we show that Th17 cells display a minimum of plasticity in acute and chronic experimental glomerulonephritis and introduce anti-CD3 treatment as a tool to induce a regulatory phenotype in Th17 cells in the kidney that may be therapeutically exploited.
Immune-mediated glomerular diseases are characterized by infiltration of T cells, which accumulate in the periglomerular space and tubulointerstitium in close contact to proximal and distal tubuli. ...Recent studies described proximal tubular epithelial cells (PTECs) as renal non-professional antigen-presenting cells that stimulate CD4
T-cell activation. Whether PTECs have the potential to induce activation of CD8
T cells is less clear. In this study, we aimed to investigate the capacity of PTECs for antigen cross-presentation thereby modulating CD8
T-cell responses. We showed that PTECs expressed proteins associated with cross-presentation, internalized soluble antigen via mannose receptor-mediated endocytosis, and generated antigenic peptides by proteasomal degradation. PTECs induced an antigen-dependent CD8
T-cell activation in the presence of soluble antigen in vitro. PTEC-activated CD8
T cells expressed granzyme B, and exerted a cytotoxic function by killing target cells. In murine lupus nephritis, CD8
T cells localized in close contact to proximal tubuli. We determined enhanced apoptosis in tubular cells and particularly PTECs up-regulated expression of cleaved caspase-3. Interestingly, induction of apoptosis in the inflamed kidney was reduced in the absence of CD8
T cells. Thus, PTECs have the capacity for antigen cross-presentation thereby inducing cytotoxic CD8
T cells in vitro, which may contribute to the pathology of immune-mediated glomerulonephritis.
Angiotensin II (Ang II) activates at least two receptors, AT1 and AT2, with the majority of its effects—such as vasoconstriction, inflammation, and matrix deposition—mediated by the AT1 receptor. It ...is thought that the AT2 receptor counteracts these processes; however, recent studies have found proinflammatory and hypertrophic effects of this receptor subtype. To identify the physiological roles of the AT2 receptor in chronic kidney disease, we performed renal ablation in AT2 receptor knockout and wild-type mice. Renal injury caused a greater impairment of renal function, glomerular injury, albuminuria, and mortality in the knockout mice than in the wild-type mice. There was increased fibronectin expression and inflammation in the knockout mice, as shown by augmented monocyte/macrophage infiltration and higher chemokine monocyte chemotactic protein-1 (MCP-1) and RANTES expression in the remnant kidney. The higher mortality and renal morbidity of the knockout mice was not due to differences in systemic blood pressure, glomerular volume, AT1 receptor, renin, or endothelial nitric oxide synthase expression. Whether activation of the AT2 receptor will have therapeutic benefit in chronic kidney disease will require further study.
Protective role for CCR5 in murine lupus nephritis Turner, Jan-Eric; Paust, Hans-Joachim; Bennstein, Sabrina B ...
American journal of physiology. Renal physiology,
2012-Jun-01, 2012-06-01, 20120601, Volume:
302, Issue:
11
Journal Article
Peer reviewed
Leukocyte infiltration is a characteristic feature of human and experimental lupus nephritis and is closely correlated with loss of renal function. The chemokine receptor CCR5 is expressed on ...monocyte and T cell subsets and is thought to play an important role in recruiting these cells into inflamed organs. To investigate the functional role of CCR5 in lupus nephritis, CCR5-deficient mice were backcrossed onto the lupus-prone MRL-Fas(lpr) (MRL/lpr) genetic background. Unexpectedly, CCR5(-/-) MRL/lpr mice developed an aggravated course of lupus nephritis in terms of glomerular tissue injury and albuminuria. Deterioration of the nephritis was associated with an overall increase in mononuclear cell infiltration into the kidney, whereas renal leukocyte subtype balance, systemic T cell response, and autoantibody formation were unaffected by CCR5 deficiency. Renal and systemic protein levels of the CCR5 ligand CCL3, which can also attract leukocytes via its alternate receptor CCR1, were significantly increased in nephritic CCR5(-/-) MRL/lpr mice. Further studies revealed that the systemic increase in the CCR5/CCR1 ligand is also observed in nonimmune CCR5(-/-) C57BL/6 mice and that this increase was due to a reduced clearance, rather than an overproduction, of CCL3. Taken together, our data support the hypothesis that CCR5-dependent consumption of its own ligands may act as a negative feedback loop to restrain local chemokine levels within inflamed tissues, thereby limiting inflammatory cell influx.
Among numerous other immune-mediated diseases, glomerulonephritis has also been suspected to be an extrahepatic manifestation of HEV infection. In this prospective study, we tested 108 patients with ...glomerulonephritis and 108 age- and sex-matched healthy controls at the University Hospital Hamburg Eppendorf, Hamburg, Germany, for anti-HEV IgG (Wantai test) as a marker for previous HEV exposure. A total of 24 patients (22%) tested positive for anti-HEV IgG. Males tended to be more frequently anti-HEV IgG positive (29%) in comparison to females (16%). However, this does not reach statistical significance (
= 0.07). Anti-HEV IgG positive patients were older in comparison to negative patients (mean 53 vs. 45 years,
= 0.05). The kidney function seems to be slightly decreased in anti-HEV IgG positive patients in comparison to and anti-HEV IgG negative patients basing on creatinine (
= 0.04) and glomerular filtration rate (GFR) (
= 0.05). Slightly higher values of bilirubin could be found in IgG positive patients (
= 0.04). Anti-HEV-IgG seropositivity rate (22%) in glomerulonephritis patients, did not differ significantly in comparison to an age- and sex-matched control cohort of healthy blood donors (31/108 positive, 29%). A total of 2/2 patients with membranoproliferative glomerulonephritis (MPGN) tested anti-HEV IgG positive (
= 0.002 in comparison to glomerulonephritis patients with other subtypes). In conclusion, our findings indicate that previous HEV exposure in a region where GT3 is endemic is not associated with glomerulonephritis in general. However, the subgroup of MPGN patients should be investigated in future studies. Furthermore, future studies are needed to investigate whether the observed association between anti-HEV IgG positivity and reduced GFR in glomerulonephritis patients is HEV associated or is an age-related effect.
Immature renal dendritic cells (DCs) are protective early in murine crescentic GN, but the mechanisms underlying this protection are unknown. Here, depletion of DCs reduced the recruitment of ...invariant natural killer T (iNKT) cells, which attenuate GN, into the kidney in the early stage of experimental crescentic GN. More than 90% of renal iNKT cells expressed the chemokine receptor CXCR6, and renal DCs produced high amounts of the cognate ligand CXCL16 early after induction of nephritis, suggesting that renal DC-derived CXCL16 might attract protective CXCR6(+) iNKT cells. Consistent with this finding, CXCR6-deficient mice exhibited less iNKT cell recruitment and developed nephritis that was more severe, similar to the aggravated nephritis observed in mice depleted of immature DCs. Finally, adoptive transfer of CXCR6-competent NKT cells ameliorated nephritis. Taken together, these results suggest an immunoprotective mechanism involving immature DCs, CXCL16, CXCR6, and regulatory iNKT cells, which might stimulate the development of new therapeutic strategies for GN.
The recruitment of inflammatory cells into renal tissue, mainly T cells and monocytes, is a typical feature of various renal diseases such as glomerulonephritis, thrombotic angiopathies, allograft ...rejection, and vasculitis. T cells predominantly infiltrate the tubulointerstitium, whereas monocytes are present in the tubulointerstitial and glomerular compartment. Because chemokines play a pivotal role in leukocyte trafficking under inflammatory conditions, this study investigated whether a differential expression of chemokines contributes to the precise coordination of leukocyte subtype trafficking in a rat model of renal microvascular endothelial injury. Renal microvascular endothelial injury was induced in rats by selective renal artery perfusion with an anti-endothelial antibody. Induction of the disease led to severe glomerular and tubulointerstitial endothelial injury with subsequent upregulation of chemokines followed by inflammatory cell recruitment. Among the analyzed chemokine mRNA, IP-10/CXCL10 (119-fold), acting via CXCR3 on activated T cells, and MCP-1/CCL2 (65-fold), acting via CCR2 on monocytes, were by far the most strongly upregulated chemokines. In situ hybridization revealed that IP-10/CXCL10 mRNA was selectively expressed by endothelial cells in the tubulointerstitial area, co-localizing with infiltrating T cells. Despite extensive damage of glomerular vasculature, no IP-10/CXCL10 expression by glomerular endothelial cells was detected. MCP-1/CCL2 mRNA in contrast was detectable in the glomerulus and the tubulointerstitium. Treatment with a neutralizing anti-IP-10/CXCL10 antibody significantly reduced the number of infiltrating tubulointerstitial T cells without affecting monocyte migration and led to an improved renal function. Our study demonstrates a role of IP-10/CXCL10 on T cell recruitment in a rat model of renal endothelial microvascular injury. Furthermore, a differential chemokine expression profile by endothelial cells in different renal compartments was found. These findings are consistent with the hypothesis that functional heterogeneity of endothelial cells from different vascular sites exists and provide an insight into the molecular mechanisms that may mediate compartment-specific T cell and monocyte recruitment in inflammatory renal disease.
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