CXCL9, but not CXCL10, promotes CXCR3-dependent immune-mediated kidney disease

Sex-specific differences in SLE - Significance in the experimental setting of inflammation and kidney damage in MRL-Faslpr mice

Animal models are an important tool in the research of chronic autoimmune diseases, like systemic lupus erythematosus (SLE). MRL-Faslpr mice are one of different lupus models that develop spontaneously an SLE-like disease with autoantibodies and immune complex deposition that leads into damage of different organs. In contrast to human SLE, both sexes of MRL-Faslpr mice develop a similar autoimmune disease. Due to the sex bias in human and the delayed disease progression in male MRL-Faslpr mice, the majority of studies have been performed in female mice. To determine the suitability of male MRL-Faslpr mice for SLE research, especially with regard to the 3 R-principle and animal welfare, analyses of phenotype, inflammation and damage with focus on kidney and spleen were performed in mice of both sexes. Female mice developed lymphadenopathy and skin lesions earlier as males. At an age of 3.5 month, more immune cells infiltrated kidney and spleen in females compared to males. At the age of 5 months, however, substantially less sex-specific differences were detected. Since other studies have shown differences between both sexes on other manifestations like autoimmune pancreatitis and Sjögren syndrome in MRL-Faslpr mice, the use of male mice as part of 3 R-principle and animal welfare must be carefully considered.

RGC-32 mediates proinflammatory and profibrotic pathways in immune-mediated kidney disease

Systemic lupus erythematosus is an autoimmune disease that results in immune-mediated damage to kidneys and other organs. We investigated the role of response gene to complement-32 (RGC-32), a proinflammatory and profibrotic mediator induced by TGFβ and C5b-9, in nephrotoxic nephritis (NTN), an experimental model that mimics human lupus nephritis. Proteinuria, loss of renal function and kidney histopathology were attenuated in RGC-32 KO NTN mice. RGC-32 KO NTN mice displayed downregulation of the CCL20/CCR6 and CXCL9/CXCR3 ligand/receptor pairs resulting in decreased renal recruitment of IL-17+ and IFNγ+ cells and subsequent decrease in the influx of innate immune cells. RGC-32 deficiency attenuated renal fibrosis as demonstrated by decreased deposition of collagen I, III and fibronectin. Thus, RGC-32 is a unique mediator shared by the Th17 and Th1 dependent proinflammatory and profibrotic pathways and a potential novel therapeutic target in the treatment of immune complex mediated glomerulonephritis such as lupus nephritis.

Activation of CD14+ Monocytes via the IFN-γ Signaling Pathway Is Associated with Immune-Related Adverse Events in Hepatocellular Carcinoma Patients Receiving PD-1 Inhibition Combination Therapy

(1) Background: Immune-related adverse events (irAEs) are a series of unique organ-specific inflammatory toxicities observed in patients with hepatocellular carcinoma (HCC) undergoing PD-1 inhibition combination therapy. The specific underlying mechanisms remain unclear. (2) Methods: We recruited 71 patients with HCC undergoing PD-1 inhibition combination therapy. These patients were then divided into two groups based on irAE occurrence: 34 had irAEs and 37 did not. Using Olink proteomics, we analyzed the aberrant inflammation-related proteins (IRPs) in these patient groups. For single-cell RNA sequencing (scRNA-seq) analysis, we collected peripheral blood mononuclear cells (PBMCs) from two representative patients at the pretreatment, irAE occurrence, and resolution stages. (3) Results: Our study revealed distinct plasma protein signatures in HCC patients experiencing irAEs after PD-1 inhibition combination therapy. We clarified the relationship between monocyte activation and irAEs, identified a strongly associated CD14-MC-CCL3 monocyte subset, and explored the role of the IFN-γ signaling pathway in monocyte activation during irAEs. (4) Conclusions: The activation of monocytes induced by the IFN-γ signaling pathway is an important mechanism underlying the occurrence of irAEs in HCC patients receiving PD-1 inhibition combination therapy.

Identification of Shared Biomarkers and Immune Infiltration Signatures between Vitiligo and Hashimoto's Thyroiditis

Background

Vitiligo and Hashimoto's thyroiditis (HT) are concomitant autoimmune diseases characterized by the destruction of melanocytes or thyrocytes. We aimed to explore the immunological mechanism of this comorbidity and screen their potential biomarkers.

Methods

We downloaded the microarray datasets from the GEO database. Differentially expressed genes (DEGs) and immune-related genes (IRGs) were selected. The immune-related differentially expressed genes (IRDEGs) were obtained by taking the intersection. Candidate biomarkers were elected by Cytoscape software. CIBERSORT was used to depict immune cell infiltration prospects. Correlation analysis was conducted between infiltrating cells and several indicators. The results were validated by real-time quantitative PCR (RT-qPCR).

Results

Three datasets and 60 IRDEGs were obtained in total. Pathway enrichment analysis showed that the T cell receptor signaling pathway, IL-17 signaling pathway, receptor-ligand activity, and signaling receptor activator activity were significantly enriched. We screened out four hub genes, including IFNG, STAT1, IL1B, and CXCL10. The ROC curve indicated the highest diagnostic value of CXCL10 in both vitiligo and HT. Immuno-infiltration analysis revealed significant changes in T cell subsets and macrophage subtypes, which were correlated with four hub genes, melanocyte markers, and thyroid-specific antigens. qPCR validated the hub genes in peripheral blood mononuclear cells from patients with comorbidity.

Conclusion

IFNG, STAT1, IL1B, and CXCL10, were the key IRDEGs to vitiligo and HT. These genes may participate in the comorbidity by remodeling the immune cell infiltration pattern, and cross-expressed antigens may mediate the common damage of melanocytes and thyroid tissues.

Proton pump inhibitors and adverse kidney outcomes during immune checkpoint blockade: time to sound the alarm?

Immune checkpoint inhibitors (ICIs) have significantly altered the treatment landscape for cancer in the last decade. However, their benefits are often offset by therapy-limiting immune-related adverse events (irAEs). Acute interstitial nephritis (AIN) is the most common renal irAE, but the exact mechanisms underlying its development are poorly understood. ICI-induced immune activation against drug-derived antigens, leading to an inflammatory response within the kidney interstitium, has been postulated, evidenced by current observations of a higher incidence of ICI-associated AIN in patients receiving AIN-inducing drugs such as proton pump inhibitors (PPIs). The role of PPIs in this specific context has garnered significant attention, given their ubiquitous use and sometimes misuse. In this issue of CKJ Miao et al. summarise and synthesize the best available evidence to clarify the interactions of PPIs with ICIs in the development of AIN and other adverse kidney outcomes. The sum of evidence provided appear to implicate PPIs in the development of clinically significant short- and long-term kidney-related adverse effects in patients on immune checkpoint blockade, although causality cannot be proven. In this editorial we discuss the key practical implications of these findings and emphasize the need for further quality studies to delineate the true relationship of ICIs and PPIs in the development of AIN.

Gene Expression Signatures in Inflammatory and Sclerotic Morphea Skin and Sera Distinguish Morphea from Systemic Sclerosis

Morphea is an inflammatory fibrotic disorder of the skin that has been likened to systemic sclerosis (SSc). We sought to examine the molecular landscape of morphea by examining lesional skin gene expression and blood biomarkers and comparing the gene expression profiles with those from site-matched nonlesional and SSc lesional skin. We found the morphea transcriptome is dominated by IFN-γ-mediated T helper 1 immune dysregulation, with a relative paucity of fibrosis pathways. Specifically, expression profiles of morphea skin clustered with the SSc inflammatory subset and were distinct from the those of SSc fibroproliferative subset. Unaffected morphea skin also differed from unaffected SSc skin because it did not exhibit pathological gene expression signatures. Examination of downstream IFN-γ-mediated chemokines, CXCL9 and CXCL10, revealed increased transcription in the skin but not in circulation. In contrast to transcriptional activity, CXCL9 was elevated in serum and was associated with active, widespread cutaneous involvement. Taken together, these results indicate that morphea is a skin-directed process characterized by T helper 1 immune-mediated dysregulation, which contrasts with fibrotic signatures and systemic transcriptional changes associated with SSc. The similarity between morphea and the inflammatory subset of SSc on transcriptional profiling indicates that therapies under development for this subset of SSc are also promising for treatment of morphea.

Mesenchymal stem cells enhance CCL8 expression by podocytes in lupus-prone MRL.Faslpr mice

Nephritis is common in systemic lupus erythematosus patients and is associated with hyper-activation of immune and renal cells. Although mesenchymal stem cells (MSCs) ameliorate nephritis by inhibiting T and B cells, whether MSCs directly affect renal cells is unclear. To address this issue, we examined the direct effect of MSCs on renal cells with a focus on chemokines. We found that expression of CCL2, CCL3, CCL4, CCL5, CCL8, CCL19, and CXCL10 increased 1.6-5.6-fold in the kidney of lupus-prone MRL.Faslpr mice with advancing age from 9 to 16 weeks. Although MSCs inhibited the increase in the expression of most chemokines by 52-95%, they further increased CCL8 expression by 290%. Using renal cells, we next investigated how MSCs enhanced CCL8 expression. CCL8 was expressed by podocytes, but not by tubular cells. MSCs enhanced CCL8 expression by podocytes in a contact-dependent manner, which was proved by transwell assay and blocking with anti-VCAM-1 antibody. Finally, we showed that CCL8 itself activated MSCs to produce more immunosuppressive factors (IL-10, IDO, TGF-β1, and iNOS) and to inhibit more strongly IFN-γ production by T cells. Taken together, our data demonstrate that MSCs activate podocytes to produce CCL8 in a contact-dependent manner and conversely, podocyte-derived CCL8 might potentiate immunosuppressive activity of MSCs in a paracrine fashion. Our study documents a previously unrecognized therapeutic mechanism of MSCs in nephritis.

Identification and validation of urinary CXCL9 as a biomarker for diagnosis of acute interstitial nephritis

BackgroundAcute tubulointerstitial nephritis (AIN) is one of the few causes of acute kidney injury with diagnosis-specific treatment options. However, due to the need to obtain a kidney biopsy for histological confirmation, AIN diagnosis can be delayed, missed, or incorrectly assumed. Here, we identify and validate urinary CXCL9, an IFN-γ-induced chemokine involved in lymphocyte chemotaxis, as a diagnostic biomarker for AIN.MethodsIn a prospectively enrolled cohort with pathologist-adjudicated histological diagnoses, termed the discovery cohort, we tested the association of 180 immune proteins measured by an aptamer-based assay with AIN and validated the top protein, CXCL9, using sandwich immunoassay. We externally validated these findings in 2 cohorts with biopsy-confirmed diagnoses, termed the validation cohorts, and examined mRNA expression differences in kidney tissue from patients with AIN and individuals in the control group.ResultsIn aptamer-based assay, urinary CXCL9 was 7.6-fold higher in patients with AIN than in individuals in the control group (P = 1.23 × 10-5). Urinary CXCL9 measured by sandwich immunoassay was associated with AIN in the discovery cohort (n = 204; 15% AIN) independently of currently available clinical tests for AIN (adjusted odds ratio for highest versus lowest quartile: 6.0 [1.8-20]). Similar findings were noted in external validation cohorts, where CXCL9 had an AUC of 0.94 (0.86-1.00) for AIN diagnosis. CXCL9 mRNA expression was 3.9-fold higher in kidney tissue from patients with AIN (n = 19) compared with individuals in the control group (n = 52; P = 5.8 × 10-6).ConclusionWe identified CXCL9 as a diagnostic biomarker for AIN using aptamer-based urine proteomics, confirmed this association using sandwich immunoassays in discovery and external validation cohorts, and observed higher expression of this protein in kidney biopsies from patients with AIN.FundingThis study was supported by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) awards K23DK117065 (DGM), K08DK113281 (KM), R01DK128087 (DGM), R01DK126815 (DGM and LGC), R01DK126477 (KNC), UH3DK114866 (CRP, DGM, and FPW), R01DK130839 (MES), and P30DK079310 (the Yale O'Brien Center). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

CXCL9 Links Skin Inflammation and Fibrosis through CXCR3-Dependent Upregulation of Col1a1 in Fibroblasts

Morphea is characterized by initial inflammation followed by fibrosis of the skin and soft tissue. Despite its substantial morbidity, the pathogenesis of morphea is poorly studied. Previous work showed that CXCR3 ligands CXCL9 and CXCL10 are highly upregulated in the sera and lesional skin of patients with morphea. We found that an early inflammatory subcutaneous bleomycin mouse model of dermal fibrosis mirrors the clinical, histological, and immune dysregulation observed in human morphea. We used this model to examine the role of the CXCR3 chemokine axis in the pathogenesis of cutaneous fibrosis. Using the REX3 (Reporting the Expression of CXCR3 ligands) mice, we characterized which cells produce CXCR3 ligands over time. We found that fibroblasts contribute the bulk of CXCL9-RFP and CXCL10-BFP by percentage, whereas macrophages produce high amounts on a per-cell basis. To determine whether these chemokines are mechanistically involved in pathogenesis, we treated Cxcl9-, Cxcl10-, or Cxcr3-deficient mice with bleomycin and found that fibrosis is dependent on CXCL9 and CXCR3. Addition of recombinant CXCL9 but not CXCL10 to cultured mouse fibroblasts induced Col1a1 mRNA expression, indicating that the chemokine itself contributes to fibrosis. Taken together, our studies provide evidence that CXCL9 and its receptor CXCR3 are functionally required for inflammatory fibrosis.

Stress keratin 17 and estrogen support viral persistence and modulate the immune environment during cervicovaginal murine papillomavirus infection

A murine papillomavirus, MmuPV1, infects both cutaneous and mucosal epithelia of laboratory mice and can be used to model high-risk human papillomavirus (HPV) infection and HPV-associated disease. We have shown that estrogen exacerbates papillomavirus-induced cervical disease in HPV-transgenic mice. We have also previously identified stress keratin 17 (K17) as a host factor that supports MmuPV1-induced cutaneous disease. Here, we sought to test the role of estrogen and K17 in MmuPV1 infection and associated disease in the female reproductive tract. We experimentally infected wild-type and K17 knockout (K17KO) mice with MmuPV1 in the female reproductive tract in the presence or absence of exogenous estrogen for 6 mon. We observed that a significantly higher percentage of K17KO mice cleared the virus as opposed to wild-type mice. In estrogen-treated wild-type mice, the MmuPV1 viral copy number was significantly higher compared to untreated mice by as early as 2 wk postinfection, suggesting that estrogen may help facilitate MmuPV1 infection and/or establishment. Consistent with this, viral clearance was not observed in either wild-type or K17KO mice when treated with estrogen. Furthermore, neoplastic disease progression and cervical carcinogenesis were supported by the presence of K17 and exacerbated by estrogen treatment. Subsequent analyses indicated that estrogen treatment induces a systemic immunosuppressive state in MmuPV1-infected animals and that both estrogen and K17 modulate the local intratumoral immune microenvironment within MmuPV1-induced neoplastic lesions. Collectively, these findings suggest that estrogen and K17 act at multiple stages of papillomavirus-induced disease at least in part via immunomodulatory mechanisms.

Glucocorticoids target the CXCL9/CXCL10-CXCR3 axis and confer protection against immune-mediated kidney injury

Glucocorticoids remain a cornerstone of therapeutic regimes for autoimmune and chronic inflammatory diseases - for example, in different forms of crescentic glomerulonephritis - because of their rapid antiinflammatory effects, low cost, and wide availability. Despite their routine use for decades, the underlying cellular mechanisms by which steroids exert their therapeutic effects need to be fully elucidated. Here, we demonstrate that high-dose steroid treatment rapidly reduced the number of proinflammatory CXCR3+CD4+ T cells in the kidney by combining high-dimensional single-cell and morphological analyses of kidney biopsies from patients with antineutrophil cytoplasmic antibody-associated (ANCA-associated) crescentic glomerulonephritis. Using an experimental model of crescentic glomerulonephritis, we show that the steroid-induced decrease in renal CD4+ T cells is a consequence of reduced T cell recruitment, which is associated with an ameliorated disease course. Mechanistic in vivo and in vitro studies revealed that steroids act directly on renal tissue cells, such as tubular epithelial cells, but not on T cells, which resulted in an abolished renal expression of CXCL9 and CXCL10 as well as in the prevention of CXCR3+CD4+ T cell recruitment to the inflamed kidneys. Thus, we identified the CXCL9/CXCL10-CXCR3 axis as a previously unrecognized cellular and molecular target of glucocorticoids providing protection from immune-mediated pathology.

Pathogenic T-Cell Responses in Immune-Mediated Glomerulonephritis

Glomerulonephritis (GN) comprises a group of immune-mediated kidney diseases affecting glomeruli and the tubulointerstitium. Glomerular crescent formation is a histopathological characteristic of severe forms of GN, also referred to as crescentic GN (cGN). Based on histological findings, cGN includes anti-neutrophil cytoplasmic antibody (ANCA)-associated GN, a severe form of ANCA-associated vasculitis, lupus nephritis associated with systemic lupus erythematosus, Goodpasture’s disease, and IgA nephropathy. The immunopathogenesis of cGN is associated with activation of CD4+ and CD8+ T cells, which particularly accumulate in the periglomerular and tubulointerstitial space but also infiltrate glomeruli. Clinical observations and functional studies in pre-clinical animal models provide evidence for a pathogenic role of Th1 and Th17 cell-mediated immune responses in cGN. Emerging evidence further argues that CD8+ T cells have a role in disease pathology and the mechanisms of activation and function of recently identified tissue-resident CD4+ and CD8+ T cells in cGN are currently under investigation. This review summarizes the mechanisms of pathogenic T-cell responses leading to glomerular damage and renal inflammation in cGN. Advanced knowledge of the underlying immune mechanisms involved with cGN will enable the identification of novel therapeutic targets for the replacement or reduction in standard immunosuppressive therapy or the treatment of refractory disease.

Identification of Genes Potentially Associated with Melanoma Tumorigenesis Through Co-Expression Network Analysis

Background

Melanoma is one of the most malignant and aggressive skin tumors, and its incidence is increasing worldwide. However, few studies have investigated the process of tumorigenesis from normal skin to melanoma.

Methods

Several bioinformatics analyses, including GEO databases, Oncomine database, TCGA database, STRING, MCODE and cytoHubba plug-ins, GEPIA, TIMER and TRRUST and DGIdb, were performed to disclose the hub genes and immunology implicated in primary melanoma tumorigenesis. Finally, immunohistochemistry (IHC) and quantitative real-time PCR (qPCR) were used to validate the results of bioinformatics analysis in vitro.

Results

A total of 295 overlapping DEGs (ODEGs) (157 upregulated and 138 downregulated) and 9 hub genes were identified between primary melanoma and normal skin tissues. Functional analysis of these 9 hub genes indicated that the genes were primarily enriched in cell chemotaxis, the chemokine-mediated signaling pathway, the extracellular region, the extracellular space, chemokine activity and CXCR3 chemokine receptor binding. KEGG pathway enrichment showed that these genes were primarily involved in the chemokine signaling pathway, cytokine–cytokine receptor interaction, the toll-like receptor signaling pathway, the cytosolic DNA-sensing pathway and the TNF signaling pathway. Upregulated CCL5, CCL4, CXCL9 and CXCL10 demonstrated good overall survival (OS), and most of them have a higher expression in stage 0 and 1 of melanoma. Moreover, immune infiltration analysis showed that the above hub genes showed a strong positive correlation between their expression and infiltration of the six immune cell subsets. Transcription factor regulation network suggested that RELA and NFKB1 are the transcription factors of CCL4, CCL5, CXCL10 and CXCL2, while IRF7, IRF3 and IRF1 are the transcription factors of CCL5 and CXCL10. Drug–gene interaction analysis identified 46 drug–gene interactions. In vitro data demonstrated that the level of CCL4, CCL5, CXCL9 and CXCL10 is higher in melanoma than that in normal skin tissues, either at tissue or cell lines level.

Conclusion

In summary, we identified 4 key chemokine members related to tumorigenesis and progression in primary melanoma, and these results may help to elucidate melanoma tumorigenesis and facilitate its treatment.

C-X-C Motif Chemokine Ligand 9 and Its CXCR3 Receptor Are the Salt and Pepper for T Cells Trafficking in a Mouse Model of Gaucher Disease

Gaucher disease is a lysosomal storage disease, which happens due to mutations in GBA1/Gba1 that encodes the enzyme termed as lysosomal acid β-glucosidase. The major function of this enzyme is to catalyze glucosylceramide (GC) into glucose and ceramide. The deficiency of this enzyme and resultant abnormal accumulation of GC cause altered function of several of the innate and adaptive immune cells. For example, augmented infiltration of T cells contributes to the increased production of pro-inflammatory cytokines, (e.g., IFNγ, TNFα, IL6, IL12p40, IL12p70, IL23, and IL17A/F). This leads to tissue damage in a genetic mouse model (Gba1^9V/-) of Gaucher disease. The cellular mechanism(s) by which increased tissue infiltration of T cells occurs in this disease is not fully understood. Here, we delineate role of the CXCR3 receptor and its exogenous C-X-C motif chemokine ligand 9 (CXCL9) in induction of increased tissue recruitment of CD4⁺ T and CD8⁺ T cells in Gaucher disease. Intracellular FACS staining of macrophages (Mϕs) and dendritic cells (DCs) from Gba1^9V/- mice showed elevated production of CXCL9. Purified CD4⁺ T cells and the CD8⁺ T cells from Gba1^9V/- mice showed increased expression of CXCR3. Ex vivo and in vivo chemotaxis experiments showed CXCL9 involvement in the recruitment of Gba1^9V/- T cells. Furthermore, antibody blockade of the CXCL9 receptor (CXCR3) on T cells caused marked reduction in CXCL9- mediated chemotaxis of T cells in Gba1^9V/- mice. These data implicate abnormalities of the CXCL9-CXCR3 axis leading to enhanced tissue recruitment of T cells in Gaucher disease. Such results provide a rationale for blockade of the CXCL9/CXCR3 axis as potential new therapeutic targets for the treatment of inflammation in Gaucher disease.

Inhibitory effects of tolerogenic probiotics on migratory potential of lupus patient-derived DCs

Objectives

The present in vitro study aimed to evaluate whether Lactobacillus delbrueckii and Lactobacillus rhamnosus treatments can induce regulatory phenotype, together with modulating the expression of chemokine receptors (CRs) in dendritic cells (DCs). The CRs of DCs have been found to be involved in the pathogenesis of Systemic lupus erythematosus (SLE) through directing recruitment and migration of immune cells.

Materials and Methods

In brief, monocytes of patients with SLE and healthy donors were isolated and differentiated to regulatory or inflammatory mature DCs through treatment with L. delbrueckii, L. rhamnosus, mixed probiotics, and LPS.

Results

FACScan analysis showed that the expression of CRs including CXCR3, CCR5, CCR4, and CCR3, was significantly reduced in all probiotic-treated groups of SLE and healthy (control) donors when compared with the LPS treated group.

Conclusion

The results demonstrated that tolerogenic probiotics could prevent or decrease the expression of inflammatory CRs on the surface of tolerogenic DCs during the maturation process.

T helper cell trafficking in autoimmune kidney diseases

CD4⁺ T cells are key drivers of autoimmune diseases, including crescentic GN. Many effector mechanisms employed by T cells to mediate renal damage and repair, such as local cytokine production, depend on their presence at the site of inflammation. Therefore, the mechanisms regulating the renal CD4⁺ T cell infiltrate are of central importance. From a conceptual point of view, there are four distinct factors that can regulate the abundance of T cells in the kidney: (1) T cell infiltration, (2) T cell proliferation, (3) T cell death and (4) T cell retention/egress. While a substantial amount of data on the recruitment of T cells to the kidneys in crescentic GN have accumulated over the last decade, the roles of T cell proliferation and death in the kidney in crescentic GN is less well characterized. However, the findings from the data available so far do not indicate a major role of these processes. More importantly, the molecular mechanisms underlying both egress and retention of T cells from/in peripheral tissues, such as the kidney, are unknown. Here, we review the current knowledge of mechanisms and functions of T cell migration in renal autoimmune diseases with a special focus on chemokines and their receptors.

Role of inflammatory chemokines in hypertension

Hypertension is associated with immune cells activation and their migration into the kidney, vasculature, heart and brain. These inflammatory mechanisms are critical for blood pressure regulation and mediate target organ damage, creating unique novel targets for pharmacological modulation. In response to angiotensin II and other pro-hypertensive stimuli, the expression of several inflammatory chemokines and their receptors is increased in the target organs, mediating homing of immune cells. In this review, we summarize the contribution of key inflammatory chemokines and their receptors to increased accumulation of immune cells in target organs and effects on vascular dysfunction, remodeling, oxidative stress and fibrosis, all of which contribute to blood pressure elevation. In particular, the role of CCL2, CCL5, CXCL8, CXCL9, CXCL10, CXCL11, CXCL16, CXCL1, CX3CL1, XCL1 and their receptors in the context of hypertension is discussed. Recent studies have tested the efficacy of pharmacological or genetic targeting of chemokines and their receptors on the development of hypertension. Promising results indicate that some of these pathways may serve as future therapeutic targets to improve blood pressure control and prevent target organ consequences including kidney failure, heart failure, atherosclerosis or cognitive impairment.

Potential therapeutic manipulations of the CXCR3 chemokine axis for the treatment of inflammatory fibrosing diseases

Chemokines play important roles in homeostasis and inflammatory processes. While their roles in leukocyte recruitment are well-appreciated, chemokines play additional roles in the body, including mediating or regulating angiogenesis, tumor metastasis and wound healing. In this opinion article, we focus on the role of CXCR3 and its ligands in fibrotic processes. We emphasize differences of the effects of each ligand, CXCL9, CXCL10 and CXCL11, on fibroblasts in different tissues of the body. We include discussions of differences in signaling pathways that may account for protective or pro-fibrotic effects of each ligand in different experimental models and ex vivo analysis of human tissues. Our goal is to highlight potential reasons why there are disparate findings in different models, and to suggest ways in which this chemokine axis could be manipulated for the treatment of fibrosis.

Renal Fibrosis Is Significantly Attenuated Following Targeted Disruption of Cd40 in Experimental Renal Ischemia

Background

Renal artery stenosis is a common cause of renal ischemia, contributing to the development of chronic kidney disease. To investigate the role of local CD40 expression in renal artery stenosis, Goldblatt 2‐kidney 1‐clip surgery was performed on hypertensive Dahl salt‐sensitive rats (S rats) and genetically modified S rats in which CD40 function is abolished (Cd40^mutant).

Methods and Results

Four weeks following the 2‐kidney 1‐clip procedure, Cd40^mutant rats demonstrated significantly reduced blood pressure and renal fibrosis in the ischemic kidneys compared with S rat controls. Similarly, disruption of Cd40 resulted in reduced 24‐hour urinary protein excretion in Cd40^mutant rats versus S rat controls (46.2±1.9 versus 118.4±5.3 mg/24 h; P<0.01), as well as protection from oxidative stress, as indicated by increased paraoxonase activity in Cd40^mutant rats versus S rat controls (P<0.01). Ischemic kidneys from Cd40^mutant rats demonstrated a significant decrease in gene expression of the profibrotic mediator, plasminogen activator inhibitor‐1 (P<0.05), and the proinflammatory mediators, C‐C motif chemokine ligand 19 (P<0.01), C‐X‐C Motif Chemokine Ligand 9 (P<0.01), and interleukin‐6 receptor (P<0.001), compared with S rat ischemic kidneys, as assessed by quantitative PCR assay. Reciprocal renal transplantation documented that CD40 exclusively expressed in the kidney contributes to ischemia‐induced renal fibrosis. Furthermore, human CD40‐knockout proximal tubule epithelial cells suggested that suppression of CD40 signaling significantly inhibited expression of proinflammatory and ‐fibrotic genes.

Conclusions

Taken together, our data suggest that activation of CD40 induces a significant proinflammatory and ‐fibrotic response and represents an attractive therapeutic target for treatment of ischemic renal disease.

Acute Kidney Injury in Children after Hematopoietic Cell Transplantation Is Associated with Elevated Urine CXCL10 and CXCL9

Acute kidney injury (AKI) is nearly universally associated with worse outcomes, especially among children after hematopoietic stem cell transplant (HCT). Our objective was to examine urinary immune biomarkers of AKI after HCT to provide insights into novel mechanisms of kidney injury in this population. Studying patients undergoing allogeneic HCT provides a unique opportunity to examine immune markers of AKI because the risk of AKI is high and the immune system newly develops after transplant. Children (>2 years old) and young adults undergoing their first allogeneic HCT and enrolled in a prospective, observational cohort study at 2 large children's hospitals had urine collected pre-HCT and monthly for the first 4 months after HCT. Urine samples at each monthly time point were assayed for 8 immune-related biomarkers. AKI was defined as a 1.5-fold increase in the monthly serum creatinine value, which was recorded ±1 day from when the research urine sample was obtained, as compared with the pre-HCT baseline. Generalized estimating equation regression analysis evaluated the association between the monthly repeated measures (urinary biomarkers and AKI). A total of 176 patients were included from 2 pediatric centers. Thirty-six patients from 1 center were analyzed as a discovery cohort and the remaining 140 patients from the second center were analyzed as a validation cohort. AKI rates were 18% to 35% depending on the monthly time point after HCT. Urine CXCL10 and CXCL9 concentrations were significantly higher among children who developed AKI compared with children who did not (P < .01) in both cohorts. In order to gain a better understanding of the cellular source for these biomarkers in the urine, we also analyzed in vitro expression of CXCL10 and CXCL9 in kidney cell lines after stimulation with interferon-γ and interferon-α. HEK293-epithelial kidney cells demonstrated interferon-induced expression of CXCL10 and CXCL9, suggesting a potential mechanism driving the key finding. CXCL10 and CXCL9 are associated with AKI after HCT and are therefore promising biomarkers to guide improved diagnostic and treatment strategies for AKI in this high-risk population.

Stress keratin 17 enhances papillomavirus infection-induced disease by downregulating T cell recruitment

High-risk human papillomaviruses (HPVs) cause 5% of human cancers. Despite the availability of HPV vaccines, there remains a strong urgency to find ways to treat persistent HPV infections, as current HPV vaccines are not therapeutic for individuals already infected. We used a mouse papillomavirus infection model to characterize virus-host interactions. We found that mouse papillomavirus (MmuPV1) suppresses host immune responses via overexpression of stress keratins. In mice deficient for stress keratin K17 (K17KO), we observed rapid regression of papillomas dependent on T cells. Cellular genes involved in immune response were differentially expressed in the papillomas arising on the K17KO mice correlating with increased numbers of infiltrating CD8+ T cells and upregulation of IFNγ-related genes, including CXCL9 and CXCL10, prior to complete regression. Blocking the receptor for CXCL9/CXCL10 prevented early regression. Our data provide a novel mechanism by which papillomavirus-infected cells evade host immunity and defines new therapeutic targets for treating persistent papillomavirus infections.

Type II but Not Type I IFN Signaling Is Indispensable for TLR7-Promoted Development of Autoreactive B Cells and Systemic Autoimmunity

TLR7 is associated with development of systemic lupus erythematosus (SLE), but the underlying mechanisms are incompletely understood. Although TLRs are known to activate type I IFN (T1IFN) signaling, the role of T1IFN and IFN-γ signaling in differential regulation of TLR7-mediated Ab-forming cell (AFC) and germinal center (GC) responses, and SLE development has never been directly investigated. Using TLR7-induced and TLR7 overexpression models of SLE, we report in this study a previously unrecognized indispensable role of TLR7-induced IFN-γ signaling in promoting AFC and GC responses, leading to autoreactive B cell and SLE development. T1IFN signaling in contrast, only modestly contributed to autoimmune responses and the disease process in these mice. TLR7 ligand imiquimod treated IFN-γ reporter mice show that CD4⁺ effector T cells including follicular helper T (Tfh) cells are the major producers of TLR7-induced IFN-γ. Transcriptomic analysis of splenic tissues from imiquimod-treated autoimmune-prone B6.Sle1b mice sufficient and deficient for IFN-γR indicates that TLR7-induced IFN-γ activates multiple signaling pathways to regulate TLR7-promoted SLE. Conditional deletion of Ifngr1 gene in peripheral B cells further demonstrates that TLR7-driven autoimmune AFC, GC and Tfh responses and SLE development are dependent on IFN-γ signaling in B cells. Finally, we show crucial B cell-intrinsic roles of STAT1 and T-bet in TLR7-driven GC, Tfh and plasma cell differentiation. Altogether, we uncover a nonredundant role for IFN-γ and its downstream signaling molecules STAT1 and T-bet in B cells in promoting TLR7-driven AFC, GC, and SLE development whereas T1IFN signaling moderately contributes to these processes.

[The clinical observation of serum specific biomarkers in patients with chronic graft-versus-host disease]

目的

研究异基因造血干细胞移植后患者血清生物标志物表达水平对慢性移植物抗宿主病（cGVHD）早期诊断的价值。

方法

采用液相悬浮芯片法检测接受异基因造血干细胞移植后发生和未发生cGVHD患者5种血清蛋白标志物（IL-1b、IL-16、CXCL9、CCL19、CCL17）表达水平。

结果

相较于未发生cGVHD的对照组，cGVHD患者血清中CXCL9、CCL17表达水平显著升高（P<0.05），其中CCL17与cGVHD的疾病严重程度相关（P<0.001）；CXCL9在皮肤损害的cGVHD患者血清中显著升高（P<0.01），CCL17在肝脏为靶器官的cGVHD患者中表达水平显著升高（P<0.01）。

结论

CXCL9联合CCL17可作为cGVHD的血清生物标志物，对辅助cGVHD诊断和评估严重程度有一定参考价值。

Chemokines in rheumatic diseases: pathogenic role and therapeutic implications

Chemokines, a family of small secreted chemotactic cytokines, and their G protein-coupled seven transmembrane spanning receptors control the migratory patterns, positioning and cellular interactions of immune cells. The levels of chemokines and their receptors are increased in the blood and within inflamed tissue of patients with rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, vasculitis or idiopathic inflammatory myopathies. Chemokine ligand-receptor interactions control the recruitment of leukocytes into tissue, which are central to the pathogenesis of these rheumatic diseases. Although the blockade of various chemokines and chemokine receptors has yielded promising results in preclinical animal models of rheumatic diseases, human clinical trials have, in general, been disappointing. However, there have been glimmers of hope from several early-phase clinical trials that suggest that sufficiently blocking the relevant chemokine pathway might in fact have clinical benefits in rheumatic diseases. Hence, the chemokine system remains a promising therapeutic target for rheumatic diseases and requires further study.

T-cell positioning by chemokines in autoimmune skin diseases

Autoimmune skin diseases are complex processes in which autoreactive cells must navigate through the skin tissue to find their targets. Regulatory T cells in the skin help to mitigate autoimmune inflammation and may in fact be responsible for the patchy nature of these conditions. In this review, we will discuss chemokines that are important for global recruitment of T cell populations to the skin during disease, as well as signals that fine-tune their localization and function. We will describe prototypical disease responses and chemokine families that mediate these responses. Lastly, we will include an overview of chemokine-targeting drugs that have been tested as new treatment strategies for autoimmune skin diseases.

IL-34-Dependent Intrarenal and Systemic Mechanisms Promote Lupus Nephritis in MRL-Faslpr Mice

BACKGROUND

In people with SLE and in the MRL-Fas^lpr lupus mouse model, macrophages and autoantibodies are central to lupus nephritis. IL-34 mediates macrophage survival and proliferation, is expressed by tubular epithelial cells (TECs), and binds to the cFMS receptor on macrophages and to a newly identified second receptor, PTPRZ.

METHODS

To investigate whether IL-34-dependent intrarenal and systemic mechanisms promote lupus nephritis, we compared lupus nephritis and systemic illness in MRL-Fas^lpr mice expressing IL-34 and IL-34 knockout (KO) MRL-Fas^lpr mice. We also assessed expression of IL-34 and the cFMS and PTPRZ receptors in patients with lupus nephritis.

RESULTS

Intrarenal IL-34 and its two receptors increase during lupus nephritis in MRL-Fas^lpr mice. In knockout mice lacking IL-34, nephritis and systemic illness are suppressed. IL-34 fosters intrarenal macrophage accumulation via monocyte proliferation in bone marrow (which increases circulating monocytes that are recruited by chemokines into the kidney) and via intrarenal macrophage proliferation. This accumulation leads to macrophage-mediated TEC apoptosis. We also found suppression of circulating autoantibodies and glomerular antibody deposits in the knockout mice. This is consistent with fewer activated and proliferating intrarenal and splenic B cells in mice lacking IL-34, and with our novel discovery that PTPRZ is expressed by macrophages, B and T cells. These findings appear translatable to human patients with lupus nephritis, whose expression of IL-34, cFMS, and PTPRZ is similar to that seen in the MRL-Fas^lpr lupus mouse model. Moreover, expression of IL-34 in TECs correlates with disease activity.

CONCLUSIONS

IL-34 is a promising novel therapeutic target for patients with lupus nephritis.

Disruption of CXCR3 function impedes the development of Sjögren's syndrome-like xerostomia in non-obese diabetic mice

The chemokine receptor CXCR3 plays an important role in T cell recruitment in various immune responses and autoimmune diseases. Expression of CXCR3 ligands, including CXCL9, CXCL10, and CXCL11, is elevated in the salivary glands of patients with Sjögren's syndrome (SS). To elucidate whether interaction between CXCR3 and its ligands is required for the development of SS, we administrated an anti-CXCR3 blocking antibody (CXCR3-173) to the non-obese diabetic (NOD) mice, a well-defined model of SS, during the stage prior to disease onset. Treatment with this anti-CXCR3 antibody significantly improved salivary secretion, indicating a remission of SS clinical manifestation. Anti-CXCR3 treatment did not affect the gross leukocyte infiltration of the submandibular glands (SMGs) as assessed by hematoxylin and eosin staining. However, flow cytometric analysis showed that anti-CXCR3 treatment markedly reduced the percentage of CXCR3⁺CD8 T and CXCR3⁺CD44⁺CD8 T cells, without affecting that of CXCR3⁺CD4 T and CXCR3⁺CD44⁺CD4 T cells in the SMGs and submandibular lymph nodes, suggesting a preferential effect of this anti-CXCR3 treatment on CXCR3-expressing effector CD8 T cells. Meanwhile, SMG expression of inflammatory factor TNF-α was markedly diminished by anti-CXCR3 treatment. In accordance, anti-CXCR3 significantly enhanced SMG expression of tight junction protein claudin-1 and water channel protein aquaporin 5, two molecules that are crucial for normal salivary secretion and can be down-regulated by TNF-α. Taken together, these findings demonstrated that the interaction between the endogenous CXCR3 and its ligands plays a pro-inflammatory and pathogenic role in the development of SS-like xerostomia in the NOD mouse model.

Tailoring Immune Responses toward Autoimmunity: Transcriptional Regulators That Drive the Creation and Collusion of Autoreactive Lymphocytes

T-dependent humoral immune responses to infection involve a collaboration between B and CD4 T cell activation, migration, and co-stimulation, thereby culminating in the formation of germinal centers (GCs) and eventual differentiation into memory cells and long-lived plasma cells (PCs). CD4 T cell-derived signals drive the formation of a tailored B cell response. Downstream of these signals are transcriptional regulators that are the critical enactors of immune cell programs. In particular, a core group of transcription factors regulate both B and T cell differentiation, identity, and function. The timing and expression levels of these transcription factors are tightly controlled, with dysregulated expression correlated to immune cell dysfunction in autoimmunity and lymphomagenesis. Recent studies have significantly advanced our understanding of both extrinsic and intrinsic regulators of autoreactive B cells and antibody-secreting PCs in systemic lupus erythematosus, rheumatoid arthritis, and other autoimmune conditions. Yet, there are still gaps in our understanding of the causative role these regulators play, as well as the link between lymphoid responses and peripheral damage. This review will focus on the genesis of immunopathogenic CD4 helper and GC B cells. In particular, we will detail the transcriptional regulation of cytokine and chemokine receptor signaling during the pathogenesis of GC-derived autoimmune conditions in both murine models and human patients.

Overview of the Mechanisms that May Contribute to the Non-Redundant Activities of Interferon-Inducible CXC Chemokine Receptor 3 Ligands

The inflammatory chemokines CXCL9, CXCL10, and CXCL11 are predominantly induced by interferon (IFN)-γ and share an exclusive chemokine receptor named CXC chemokine receptor 3 (CXCR3). With a prototype function of directing temporal and spatial migration of activated T cells and natural killer cells, and inhibitory effects on angiogenesis, these CXCR3 ligands have been implicated in infection, acute inflammation, autoinflammation and autoimmunity, as well as in cancer. Intense former research efforts led to recent and ongoing clinical trials using CXCR3 and CXCR3 ligand targeting molecules. Scientific evidence has claimed mutual redundancy, ligand dominance, collaboration or even antagonism, depending on the (patho)physiological context. Most research on their in vivo activity, however, illustrates that CXCL9, CXCL10, and CXCL11 each contribute to the activation and trafficking of CXCR3 expressing cells in a non-redundant manner. When looking into detail, one can unravel a multistep machinery behind final CXCR3 ligand functions. Not only can specific cell types secrete individual CXCR3 interacting chemokines in response to certain stimuli, but also the receptor and glycosaminoglycan interactions, major associated intracellular pathways and susceptibility to processing by particular enzymes, among others, seem ligand-specific. Here, we overview major aspects of the molecular properties and regulatory mechanisms of IFN-induced CXCR3 ligands, and propose that their in vivo non-redundancy is a reflection of the unprecedented degree of versatility that seems inherent to the IFN-related CXCR3 chemokine system.

CXCL9, CXCL10, CXCL11/CXCR3 axis for immune activation - A target for novel cancer therapy

Chemokines are proteins which induce chemotaxis, promote differentiation of immune cells, and cause tissue extravasation. Given these properties, their role in anti-tumor immune response in the cancer environment is of great interest. Although immunotherapy has shown clinical benefit for some cancer patients, other patients do not respond. One of the mechanisms of resistance to checkpoint inhibitors may be chemokine signaling. The CXCL9, -10, -11/CXCR3 axis regulates immune cell migration, differentiation, and activation, leading to tumor suppression (paracrine axis). However, there are some reports that show involvements of this axis in tumor growth and metastasis (autocrine axis). Thus, a better understanding of CXCL9, -10, -11/CXCR3 axis is necessary to develop effective cancer control. In this article, we summarize recent evidence regarding CXCL9, CXCL10, CXCL11/CXCR3 axis in the immune system and discuss their potential role in cancer treatment.

Advanced glycation end products induce the apoptosis of and inflammation in mouse podocytes through CXCL9-mediated JAK2/STAT3 pathway activation

Diabetic nephropathy (DN) is a serious and one of the most common microvascular complications of diabetes. There is accumulating evidence to indicate that advanced glycation end products (AGEs), senescent macroprotein derivatives formed at an accelerated rate under conditions of diabetes, play a role in DN. In this study, we found that the serum and urine levels of C-X-C motif chemokine ligand 9 (CXCL9) were significantly elevated in patients with DN compared with healthy controls. Based on an in vitro model of mouse podocyte injury, AGEs decreased the proliferation of podocytes and increased the expression of CXCL9 and C-X-C motif chemokine receptor 3 (CXCR3), and promoted the activation of signal transducer and activator of transcription 3 (STAT3). The knockdown of CXCL9 by the transfection of mouse podoyctes with specific siRNA significantly increased the proliferation and decreased the apoptosis of the podoyctes. Moreover, the levels of inflammatory factors, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6 were also decreased in the podoyctes transfected with siRNA-CXCL9, accompanied by the increased expression of nephrin and podocin, and decreased levels of Bax/Bcl-2 and activated caspase-3. The knockdown of CXCL9 also led to the inactivation of the Janus kinase 2 (JAK2)/STAT3 pathway. Importantly, the use of the JAK2 inhibitor, AG490, and valsartan (angiotensin II receptor antagonist) attenuated the injury induced to mouse podoyctes by AGEs. On the whole, and to the best of our knowledge, this study demonstrates for the first time that AGEs exert pro-apoptotic and pro-inflammatory effects in mouse podoyctes through the CXCL9-mediated activation of the JAK2/STAT3 pathway. Thus, our data provide a potential therapeutic target for DN.

CXCR3 knockdown protects against high glucose-induced podocyte apoptosis and inflammatory cytokine production at the onset of diabetic nephropathy

Chemokines and their receptors play an important role in the pathogenesis of acute and chronic diabetic nephropathy (DN). However, their expression pattern and function in glomerular podocytes have not been investigated as of yet. In the present study, we investigated whether CXCR3 could protect podocytes from high glucose-induced apoptosis and inflammatory cytokine production and explored the possible mechanism. Cell viability, cell cycle and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry, respectively. The level of intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (∆Ψm) was measured using a dichlorofluorescein diacetate (DCFH-DA) ortetrechloro-tetraethylbenzimidazol carbocyanine iodide (JC-1) fluorescent probe, respectively. Quantitative real-time PCR was used to determine the gene expression of CXCR3. Western blots were carried out for the related protein expression in podocytes, including CXCR3, Nephrin, Podocin, Bcl-2, Bax, and Caspase-3. Firstly, we found that CXCR3 expression was significantly up-regulated and cell viability was decreased in high glucose (HG)-treated mouse podocytes in a dose-dependent manner. Secondly, knockdown of CXCR3 in mouse podocytes significantly suppressed HG-induced viability decrease, cell cycle arrest, ROS generation and ∆Ψm reduction. Moreover, knockdown of CXCR3 reduced the podocytes injury in cell apoptosis and inflammation through increasing the expression of Nephrin, Podocin and Bcl-2, and decreasing the expression of Bax and Caspase-3. In conclusion, CXCR3 knockdown protected podocytes from HG-induced apoptosis and inflammation in vitro, suggesting that inhibition of CXCR3 may have a therapeutic potential in DN treatment.

(5R)-5-hydroxytriptolide ameliorates lupus nephritis in MRL/lpr mice by preventing infiltration of immune cells

(5R)-5-hydroxytriptolide (LLDT-8), a triptolide derivative with low toxicity, was previously reported to have strong immunosuppressive effects both in vitro and in vivo, but it remains unknown whether LLDT-8 has a therapy effect on systemic lupus erythematosus. In this study, we aimed to investigate the therapeutic effects of LLDT-8 on lupus nephritis in MRL/lpr mice, a model of systemic lupus erythematosus. Compared with the vehicle group, different clinical parameters were improved upon LLDT-8 treatment as follows: prolonged life span of mice, decreased proteinuria, downregulated blood urea nitrogen and serum creatinine, reduced glomerular IgG deposits, and ameliorated histopathology. A decreased expression of the inflammatory cytokines IFN-γ, IL-17, IL-6, and TNF-α was also observed in the kidney of LLDT-8 treated MRL/lpr mice. Moreover, infiltration of T cells in the kidney was mitigated after LLDT-8 treatment, corresponding with decreased expression of related chemokines IP-10, Mig, and RANTES in the kidney. The proportion of macrophage and neutrophil cells and related chemokines expression was also reduced in kidneys of LLDT-8-treated mice. In the human proximal tubule epithelial cell line and mouse mesangial cell line, consistent with our in vivo experimental results, LLDT-8 suppressed the expression of related chemokines and IL-6. In summary, LLDT-8 has a therapeutic benefit for lupus nephritis via suppressing chemokine expression and inhibiting immune cell infiltration in kidneys of MRL/lpr mice.

Plasma biomarkers of risk for death in a multicenter phase 3 trial with uniform transplant characteristics post-allogeneic HCT

A phase 3 clinical trial (BMT CTN 0402) comparing tacrolimus/sirolimus (Tac/Sir) vs tacrolimus/methotrexate (Tac/Mtx) as graft-versus-host disease (GVHD) prophylaxis after matched-related allogeneic hematopoietic cell transplantation (HCT) recently showed no difference between study arms in acute GVHD-free survival. Within this setting of a prospective, multicenter study with uniform GVHD prophylaxis, conditioning regimen, and donor source, we explored the correlation of 10 previously identified biomarkers with clinical outcomes after allogeneic HCT. We measured biomarkers from plasma samples collected in 211 patients using enzyme-linked immunosorbent assay (Tac/Sir = 104, Tac/Mtx = 107). High suppression of tumorigenicity-2 (ST2) and T-cell immunoglobulin mucin-3 (TIM3) at day 28 correlated with 2-year nonrelapse mortality in multivariate analysis (P = .0050, P = .0075, respectively) and in a proportional hazards model with time-dependent covariates (adjusted hazard ratio: 2.43 [1.49-3.95], P = .0038 and 4.87 [2.53-9.34], P < .0001, respectively). High ST2 and TIM3 correlated with overall survival. Chemokine (C-X-C motif) ligand 9 (CXCL9) levels above the median were associated with chronic GVHD compared with levels below the median in a time-dependent proportional hazard analysis (P = .0069). Low L-Ficolin was associated with hepatic veno-occlusive disease (P = .0053, AUC = 0.80). We confirmed the correlation of plasma-derived proteins, previously assessed in single-center cohorts, with clinical outcomes after allogeneic HCT within this prospective, multicenter study.

CXCR3 Blockade Inhibits T Cell Migration into the Skin and Prevents Development of Alopecia Areata

Alopecia areata (AA) is an autoimmune disease of the hair follicle that results in hair loss of varying severity. Recently, we showed that IFN-γ-producing NKG2D(+)CD8(+) T cells actively infiltrate the hair follicle and are responsible for its destruction in C3H/HeJ AA mice. Our transcriptional profiling of human and mouse alopecic skin showed that the IFN pathway is the dominant signaling pathway involved in AA. We showed that IFN-inducible chemokines (CXCL9/10/11) are markedly upregulated in the skin of AA lesions, and further, that the IFN-inducible chemokine receptor, CXCR3, is upregulated on alopecic effector T cells. To demonstrate whether CXCL9/10/11 chemokines were required for development of AA, we treated mice with blocking Abs to CXCR3, which prevented the development of AA in the graft model, inhibiting the accumulation of NKG2D(+)CD8(+) T cells in the skin and cutaneous lymph nodes. These data demonstrate proof of concept that interfering with the Tc1 response in AA via blockade of IFN-inducible chemokines can prevent the onset of AA. CXCR3 blockade could be approached clinically in human AA with either biologic or small-molecule inhibition, the latter being particularly intriguing as a topical therapeutic.

Chemokines and Chemokine Receptors in the Development of Lupus Nephritis

Lupus nephritis (LN) is a major cause of morbidity and mortality in the patients with systemic lupus erythematosus (SLE), an autoimmune disease with damage to multiple organs. Leukocyte recruitment into the inflamed kidney is a critical step to promote LN progression, and the chemokine/chemokine receptor system is necessary for leukocyte recruitment. In this review, we summarize recent studies on the roles of chemokines and chemokine receptors in the development of LN and discuss the potential and hurdles of developing novel, chemokine-based drugs to treat LN.

Chemokine and chemokine receptors in autoimmunity: the case of primary biliary cholangitis

Chemokines represent a major mediator of innate immunity and play a key role in the selective recruitment of cells during localized inflammatory responses. Beyond critical extracellular mediators of leukocyte trafficking, chemokines and their cognate receptors are expressed by a variety of resident and infiltrating cells (monocytes, lymphocytes, NK cells, mast cells, and NKT cells). Chemokines represent ideal candidates for mechanistic studies (particularly in murine models) to better understand the pathogenesis of chronic inflammation and possibly become biomarkers of disease. Nonetheless, therapeutic approaches targeting chemokines have led to unsatisfactory results in rheumatoid arthritis, while biologics against pro-inflammatory cytokines are being used worldwide with success. In this comprehensive review we will discuss the evidence supporting the involvement of chemokines and their specific receptors in mediating the effector cell response, utilizing the autoimmune/primary biliary cholangitis setting as a paradigm.

The Changing Landscape of Renal Inflammation

Kidney inflammation is a major contributor to progressive renal injury, leading to glomerulonephritis (GN) and chronic kidney disease. We review recent advances in our understanding of leukocyte accumulation in the kidney, emphasizing key chemokines involved in GN. We discuss features of renal inflammation such as the evolving concept of immune cell plasticity. We also describe certain aspects of organ-specific tissue microenvironments in shaping immune cell responses, as well as the current knowledge of how regulatory T lymphocytes impact on other immune effector cell populations to control inflammation. It is clear that present and future research in these areas may contribute to the development of novel targeted therapeutics, with the hope of alleviating the burden of end-stage renal disease (ESRD).

CXCR3+ Regulatory T Cells Control TH1 Responses in Crescentic GN

Chemokines and chemokine receptors are implicated in regulatory T cell (Treg) trafficking to sites of inflammation and suppression of excessive immune responses in inflammatory and autoimmune diseases; however, the specific requirements for Treg migration into the inflamed organs and the positioning of these cells within the tissue are incompletely understood. Here, we report that Tregs expressing the TH1-associated chemokine receptor CXCR3 are enriched in the kidneys of patients with ANCA-associated crescentic GN and colocalize with CXCR3(+) effector T cells. To investigate the functional role of CXCR3(+) Tregs, we generated mice that lack CXCR3 in Tregs specifically (Foxp3(eGFP-Cre) × Cxcr3(fl/fl)) and induced experimental crescentic GN. Treg-specific deletion of CXCR3 resulted in reduced Treg recruitment to the kidney and an overwhelming TH1 immune response, with an aggravated course of the nephritis that was reversible on anti-IFNγ treatment. Together, these findings show that a subset of Tregs expresses CXCR3 and thereby, acquires trafficking properties of pathogenic CXCR3(+) TH1 cells, allowing Treg localization and control of excessive TH1 responses at sites of inflammation.

CX3CL1-CX3CR1 Interaction Increases the Population of Ly6C(-)CX3CR1(hi) Macrophages Contributing to Unilateral Ureteral Obstruction-Induced Fibrosis

Chemokines modulate inflammatory responses that are prerequisites for kidney injury. The specific role of monocyte-associated CX3CR1 and its cognate ligand CX3CL1 in unilateral ureteral obstruction (UUO)-induced kidney injury remains unclear. In this study, we found that UUO caused a CCR2-dependent increase in numbers of Ly6C(hi) monocytes both in the blood and kidneys and of Ly6C(-)CX3CR1(+) macrophages in the obstructed kidneys of mice. Using CX3CR1(gfp/+) knockin mice, we observed a rapid conversion of infiltrating proinflammatory Ly6C(+)CX3CR1(1o) monocytes/macrophages to anti-inflammatory Ly6C(-)CX3CR1(hi) macrophages. CX3CR1 deficiency affected neither monocyte trafficking nor macrophage differentiation in vivo upon renal obstruction, but CX3CR1 expression in monocytes and macrophages was required for increases in fibrosis in the obstructed kidneys. Mechanistically, CX3CL1-CX3CR1 interaction increases Ly6C(-)CX3CR1(hi) macrophage survival within the obstructed kidneys. Therefore, CX3CL1 and CX3CR1 may represent attractive therapeutic targets in obstructive nephropathy.

Significant Association between Serum Monokine Induced by Gamma Interferon and Carotid Intima Media Thickness

AIM

The immune system may play an important role in the pathogenesis of cardiovascular disease. T cell-driven inflammation in human hypertension and atherosclerosis has recently been revealed. In the present study, we evaluated the association between serum levels of the C-X-C chemokine receptor type 3 chemokines and the carotid intima media thickness (IMT) in humans.

METHODS

One hundred sixty-four consecutive patients undergoing baseline and 2-year follow-up carotid IMT (110 men, 62.4±10.0 years) were enrolled. The maximum carotid IMT (max-IMT) and the mean carotid IMT (mean-IMT) were measured at baseline and after 24 months. Clinical and laboratory variables, including serum levels of the monokine induced by gamma interferon (MIG) and interferon gamma-induced protein 10 (IP-10), were analyzed at the time of initial enrollment.

RESULTS

The baseline max- and mean-IMT were 0.992±0.235 and 0.793±0.191 mm, respectively. The serum levels of MIG and IP-10 significantly correlated with the carotid IMT. However, there was no significant correlation between the serum levels of MIG or IP-10 and IMT changes. A multivariate regression analysis revealed the serum MIG to be independently associated with the carotid IMT (max-IMT: β=0.194, p=0.010; mean-IMT: β=0.184, p=0.016) when controlled for age, sex, diabetes mellitus history, smoking history, body mass index, blood pressure, total cholesterol, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and aspirin and statin medication.

CONCLUSIONS

Circulating MIG levels are independently associated with the carotid IMT, after adjusting for confounding factors and medications. These findings indicate the potential clinical implication of MIG with respect to early atherosclerosis in humans.

CXCL10 is critical for the progression and maintenance of depigmentation in a mouse model of vitiligo

Vitiligo is an autoimmune disease of the skin that results in disfiguring white spots. There are no U.S. Food and Drug Administration-approved treatments for vitiligo, and most off-label treatments yield unsatisfactory results. Vitiligo patients have increased numbers of autoreactive, melanocyte-specific CD8(+) T cells in the skin and blood, which are directly responsible for melanocyte destruction. We report that gene expression in lesional skin from vitiligo patients revealed an interferon-γ (IFN-γ)-specific signature, including the chemokine CXCL10. CXCL10 was elevated in both vitiligo patient skin and serum, and CXCR3, its receptor, was expressed on pathogenic T cells. To address the function of CXCL10 in vitiligo, we used a mouse model of disease that also exhibited an IFN-γ-specific gene signature, expression of CXCL10 in the skin, and up-regulation of CXCR3 on antigen-specific T cells. Mice that received Cxcr3(-/-) T cells developed minimal depigmentation, as did mice lacking Cxcl10 or treated with CXCL10-neutralizing antibody. CXCL9 promoted autoreactive T cell global recruitment to the skin but not effector function, whereas CXCL10 was required for effector function and localization within the skin. Surprisingly, CXCL10 neutralization in mice with established, widespread depigmentation induces reversal of disease, evidenced by repigmentation. These data identify a critical role for CXCL10 in both the progression and maintenance of vitiligo and thereby support inhibiting CXCL10 as a targeted treatment strategy.

Progression of autoimmune hepatitis is mediated by IL-18-producing dendritic cells and hepatic CXCL9 expression in mice

Clinical manifestations of autoimmune hepatitis (AIH) range from mild chronic to acute, sometimes fulminant hepatitis. However, it is unknown how the progression to fatal hepatitis occurs. We developed a mouse model of fatal AIH by inducing a concurrent loss of forkhead box P3(+) regulatory T cells and programmed cell death-1 (PD-1)-mediated signaling. In this model, dysregulated follicular helper T cells in the spleen are responsible for the induction, and the C-C chemokine receptor 6/C-C chemokine ligand 20 axis is crucial for the migration of these T cells into the liver. Using this fatal AIH model, we aimed to clarify key molecules triggering fatal AIH progression. During progression, T-bet together with interferon (IFN)-γ and C-X-C chemokine receptor (CXCR)3 were highly expressed in the inflamed liver, suggesting helper T (Th)1-type inflammation. T cells that dominantly expanded in the spleen and the inflamed liver were CXCR3-expressing CD8(+) T cells; depletion of these CD8(+) T cells suppressed AIH progression. Expression of one CXCR3 ligand, chemokine (C-X-C motif) ligand (CXCL)9, was elevated in the liver. CXCL9-expressing macrophages/Kupffer cells were colocalized with infiltrating T cells, and in vivo administration of anti-CXCL9 suppressed AIH progression. In addition, serum levels of interleukin (IL)-18, but not IL-1β, were elevated during progression, and dendritic cells in the spleen and liver highly produced IL-18. In vivo administration of anti-IL-18R suppressed the increase of splenic CXCR3(+) T cells and the progression to fatal AIH. Moreover, tumor necrosis factor alpha, but not IFN-γ, was involved in up-regulating CXCL9 in the liver and for increased serum levels of IL-18.

CONCLUSION

These data suggest that, in our mouse model, fatal progression of AIH is mediated by IL-18-dependent differentiation of T cells into Th1 cells and effector T cells, respectively, and that CXCR3-CXCL9 axis-dependent migration of those T cells is crucial for fatal progression.

Expression of macrophage markers in cryoglobulinemic glomerulonephritis - a possible role of CXCL9

PURPOSE

Cryoglobulinemic glomerulonephritis (CGGN) is a type of membranoproliferative glomerulonephritis (MPGN) that develops in patients with systemic cryoglobulinemia. To date the exact pathogenesis of CGGN remains unclear. It has been suggested that macrophages may be significant contributors to the glomerular injury in this disease. In our study we attempt to characterize the macrophages in human CGGN using classical activation and regulatory macrophage markers.

MATERIAL AND METHOD

We searched our database for renal biopsy cases of CGGN. Macrophages were detected using a monoclonal anti-CD68 antibody. Two groups of macrophage markers were used: classical activation markers, including iNOS, CXCL9 and CCL20, and regulatory markers: SPHK1 and LIGHT. The stains were performed using immunohistochemical method.

RESULTS

Five patients with CGGN were identified. Four patients had systemic cryoglobulinemia and two had a serological evidence of hepatitis C virus infection. In all cases the glomeruli contained numerous macrophages. Staining for activatory macrophage markers revealed a strong nuclear staining for CXCL9 in numerous cells, including those corresponding to the macrophage location. Staining for the other activatory markers, as well as staining for regulatory markers, was not significant.

CONCLUSION

In this study of human CGGN we showed a striking expression of cytokine CXCL9, a classical macrophage activation marker, by the macrophages and possibly other cell types within the glomeruli. This observation points to the possible role of classically activated macrophages in the pathogenesis of MPGN. If this observation is confirmed on a larger group of patients, the cytokine CXCL9 could become a potential therapeutic target for human CGGN.

Update on crescentic glomerulonephritis

The recent years have seen a number of major progresses in the field of extracapillary glomerulonephritis. This entity is the final damage caused by unrelated immunological disorders such as immune complexes glomerular deposits or microvascular injury caused by proinflammatory cytokines, neutrophil extracellular traps (NET), and cell adhesion molecules in the context of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This review provides a summary of recent advances in the understanding of crescentic glomerulonephritis, focusing on interplays of local immune cells and on local mediators participating to crescent formation especially in anti-glomerular basement membrane (anti-GBM) antibody disease. The recent advances about AAV and lupus nephritis are covered by other chapters of this issue. Nevertheless, these considerations may apply to the general case of crescentic glomerulonephritis of all causes.

Comparative effects of n-3, n-6 and n-9 unsaturated fatty acid-rich diet consumption on lupus nephritis, autoantibody production and CD4+ T cell-related gene responses in the autoimmune NZBWF1 mouse

Mortality from systemic lupus erythematosus (SLE), a prototypical autoimmune disease, correlates with the onset and severity of kidney glomerulonephritis. There are both preclinical and clinical evidence that SLE patients may benefit from consumption of n-3 polyunsaturated fatty acids (PUFA) found in fish oil, but the mechanisms remain unclear. Here we employed the NZBWF1 SLE mouse model to compare the effects of dietary lipids on the onset and severity of autoimmune glomerulonephritis after consuming: 1) n-3 PUFA-rich diet containing docosahexaenoic acid-enriched fish oil (DFO), 2) n-6 PUFA-rich Western-type diet containing corn oil (CRN) or 3) n-9 monounsaturated fatty acid (MUFA)-rich Mediterranean-type diet containing high oleic safflower oil (HOS). Elevated plasma autoantibodies, proteinuria and glomerulonephritis were evident in mice fed either the n-6 PUFA or n-9 MUFA diets, however, all three endpoints were markedly attenuated in mice that consumed the n-3 PUFA diet until 34 wk of age. A focused PCR array was used to relate these findings to the expression of 84 genes associated with CD4+ T cell function in the spleen and kidney both prior to and after the onset of the autoimmune nephritis. n-3 PUFA suppression of autoimmunity in NZBWF1 mice was found to co-occur with a generalized downregulation of CD4+ T cell-related genes in kidney and/or spleen at wk 34. These genes were associated with the inflammatory response, antigen presentation, T cell activation, B cell activation/differentiation and leukocyte recruitment. Quantitative RT-PCR of representative affected genes confirmed that n-3 PUFA consumption was associated with reduced expression of CD80, CTLA-4, IL-10, IL-18, CCL-5, CXCR3, IL-6, TNF-α and osteopontin mRNAs in kidney and/or spleens as compared to mice fed n-6 PUFA or n-9 MUFA diets. Remarkably, many of the genes identified in this study are currently under consideration as biomarkers and/or biotherapeutic targets for SLE and other autoimmune diseases.