Distinct expression of CCR1 and CCR5 in glomerular and interstitial lesions of human glomerular diseases

Characterization of macrophages in ischemia-reperfusion injury-induced acute kidney injury based on single-cell RNA-Seq and bulk RNA-Seq analysis

Acute kidney injury (AKI) is a complex disease, with macrophages playing a vital role in its progression. However, the mechanism of macrophage function remains unclear and strategies targeting macrophages in AKI are controversial. To address this issue, we used single-cell RNA-seq analysis to identify macrophage sub-types involved in ischemia-reperfusion-induced AKI, and then screened for associated hub genes using intersecting bulk RNA-seq data. The single-cell and bulk RNA-seq datasets were obtained from the Gene Expression Omnibus (GEO) database. Screening of differentially-expressed genes (DEGs) and pseudo-bulk DEG analyses were used to identify common hub genes. Pseudotime and trajectory analyses were performed to investigate the progression of cell differentiation. CellChat analysis was performed to reveal the crosstalk between cell clusters. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to identify enriched pathways in the cell clusters. Immunofluorescence and RT-PCR were preformed to validate the expression of the identified hub genes. Four hub genes, Vim, S100a6, Ier3, and Ccr1, were identified in the infiltrated macrophages between normal samples and those 3 days after ischemia-reperfusion renal injury (IRI); all were associated with the progression of IRI-induced AKI. Increased expression of Vim, S100a6, Ier3, and Ccr1 in infiltrated macrophages may be associated with inflammatory responses and may mediate crosstalk between macrophages and renal tubular epithelial cells under IRI conditions. Our results reveal that Ier3 may be critical in AKI, and that Vim, S100a6, Ier3, and Ccr1 may act as novel biomarkers and potential therapeutic targets for IRI-induced AKI.

Immunophenotyping of Monocyte Migration Markers and Therapeutic Effects of Selenium on IL-6 and IL-1β Cytokine Axes of Blood Mononuclear Cells in Preoperative and Postoperative Coronary Artery Disease Patients

Multivessel coronary artery disease (CAD) is characterized by underlying chronic vascular inflammation and occlusion in the coronary arteries, where these patients undergo coronary artery bypass grafting (CABG). Since post-cardiotomy inflammation is a well known phenomenon after CABG, attenuation of this inflammation is required to reduce perioperative morbidity and mortality. In this study, we aimed to phenotype circulating frequencies and intensities of monocyte subsets and monocyte migration markers, respectively, and to investigate the plasma level of inflammatory cytokines and chemokines between preoperative and postoperative CAD patients and later, to intervene the inflammation with sodium selenite. We found a higher amplitude of inflammation, postoperatively, in terms of CCR1high monocytes and significantly increased pro-inflammatory cytokines, IL-6, IL-8, and IL-1RA. Further, in vitro intervention with selenium displayed mitigating effects on the IL-6/STAT-3 axis of mononuclear cells derived from postoperative CAD patients. In addition, in vitro selenium intervention significantly reduced IL-1β production as well as decreased cleaved caspase-1 (p20) activity by preoperative (when stimulated) as well as postoperative CAD mononuclear cells. Though TNF-α exhibited a positive correlation with blood troponin levels in postoperative CAD patients, there was no obvious effect of selenium on the TNF-α/NF-κB axis. In conclusion, anti-inflammatory selenium might be utilized to impede systemic inflammatory cytokine axes to circumvent aggravating atherosclerosis and further damage to the autologous bypass grafts during the post-surgical period.

Role of the CX3CL1-CX3CR1 axis in renal disease

Excessive infiltration of immune cells into the kidney is a key feature of acute and chronic kidney diseases. The family of chemokines comprises key drivers of this process. Fractalkine [chemokine (C-X3-C motif) ligand 1 (CX3CL1)] is one of two unique chemokines synthesized as a transmembrane protein that undergoes proteolytic cleavage to generate a soluble species. Through interacting with its cognate receptor, chemokine (C-X3-C motif) receptor 1 (CX3CR1), CX3CL1 was originally shown to act as a conventional chemoattractant in the soluble form and as an adhesion molecule in the transmembrane form. Since then, other functions of CX3CL1 beyond leukocyte recruitment have been described, including cell survival, immunosurveillance, and cell-mediated cytotoxicity. This review summarizes diverse roles of CX3CL1 in kidney disease and potential uses as a therapeutic target and novel biomarker. As the CX3CL1-CX3CR1 axis has been shown to contribute to both detrimental and protective effects in various kidney diseases, a thorough understanding of how the expression and function of CX3CL1 are regulated is needed to unlock its therapeutic potential.

Betamethasone induces potent immunosuppression and reduces HIV infection in a PBMC in vitro model

Genital inflammation is an established risk factor for increased HIV acquisition risk. Certain HIV-exposed seronegative populations, who are naturally resistant to HIV infection, have an immune quiescent phenotype defined by reduced immune activation and inflammatory cytokines at the genital tract. Therefore, the aim of this study was to create an immune quiescent environment using immunomodulatory drugs to mitigate HIV infection. Using an in vitro peripheral blood mononuclear cell (PBMC) model, we found that inflammation was induced using phytohemagglutinin and Toll-like receptor (TLR) agonists Pam3CSK4 (TLR1/2), lipopolysaccharide (LPS) (TLR4) and R848 (TLR7/8). After treatment with anti-inflammatory drugs, ibuprofen (IBF) and betamethasone (BMS), PBMCs were exposed to HIV NL4-3 AD8. Multiplexed ELISA was used to measure 28 cytokines to assess inflammation. Flow cytometry was used to measure immune activation (CD38, HLA-DR and CCR5) and HIV infection (p24 production) of CD4+ T cells. BMS potently suppressed inflammation (soluble cytokines, p<0.05) and immune activation (CD4+ T cells, p<0.05). BMS significantly reduced HIV infection of CD4+ T cells only in the LPS (0.98%) and unstimulated (1.7%) conditions (p<0.02). In contrast, IBF had minimal anti-inflammatory and immunosuppressive but no anti-HIV effects. BMS demonstrated potent anti-inflammatory effects, regardless of stimulation condition. Despite uniform immunosuppression, BMS differentially affected HIV infection according to the stimulation conditions, highlighting the complex nature of these interactions. Together, these data underscore the importance of interrogating inflammatory signaling pathways to identify novel drug targets to mitigate HIV infection.

Identification of CD2, CCL5 and CCR5 as potential therapeutic target genes for renal interstitial fibrosis

Background

We aimed to explore potential gene biomarkers of renal interstitial fibrosis (RIF) due to a lack of effective and non-invasive methods for diagnosis.

Methods

Three data sets (GSE22459, GSE76882 and GSE57731) including 350 samples were acquired from Gene Expression Omnibus (GEO) database. We used bioconductor limma package to perform background adjustment. Cluster analysis was conducted by 'edgeR' package to identify the differentially expressed genes (DEGs). We generated heat maps with using heatmap package in R software. Function annotation of genes was performed by Gene Ontology (GO) enrichment analysis. STRING (Search Tool for the Retrieval of Interacting Genes) database was employed to construct the protein-protein interaction (PPI) network and the results were visualized by Cytoscape 3.6.1. At last, we applied Graphpad Prism 7.0. to explore the correlation between three hub genes and pathological degrees of RIF.

Results

By applying the "edgeR" package in R, we detected 116 DEGs with three data sets. These genes were enriched in 19 GO biological process categories. Three main hub genes (CD2, CCL5 and CCR5) were identified after construction of PPI network. In Pearson correlation coefficient, CD2, CCL5 and CCR5 was found to hold higher expression patterns in RIF samples based on independent data set GSE57731. Besides, their gene expression levels were found significantly positive correlation with the degree of RIF (CD2: P<0.05, r=0.29; CCL5: P<0.05, r=0.31; CCR5: P<0.05, r=0.38).

Conclusions

CD2, CCL5 and CCR5 might serve as potential early biomarkers of RIF. The mechanism between these genes and RIF remains to be further studied.

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.

Murine Renal Transcriptome Profiles Upon Leptospiral Infection: Implications for Chronic Kidney Diseases

Background

Leptospirosis caused by pathogenic Leptospira spp leads to kidney damage that may progress to chronic kidney disease. However, how leptospiral infections induced renal damage is unclear.

Methods

We apply microarray and next-generation sequencing technologies to investigate the first murine transcriptome-wide, leptospires-mediated changes in renal gene expression to identify biological pathways associated with kidney damage.

Results

Leptospiral genes were detected in renal transcriptomes of mice infected with Leptospira interrogans at day 28 postinfection, suggesting colonization of leptospires within the kidney with propensity of chronicity. Comparative differential gene expression and pathway analysis were investigated in renal transcriptomes of mice infected with pathogens and nonpathogens. Pathways analysis showed that Toll-like receptor signaling, complements activation, T-helper 1 type immune response, and T cell-mediated immunity/chemotaxis/proliferation were strongly associated with progressive tubulointerstitial damage caused by pathogenic leptospiral infection. In addition, 26 genes related with complement system, immune function, and cell-cell interactions were found to be significantly up-regulated in the L interrogans-infected renal transcriptome.

Conclusions

Our results provided comprehensive knowledge regarding the host transcriptional response to leptospiral infection in murine kidneys, particularly the involvement of cell-to-cell interaction in the immune response. It would provide valuable resources to explore functional studies of chronic renal damage caused by leptospiral infection.

CKD-506, a novel HDAC6-selective inhibitor, improves renal outcomes and survival in a mouse model of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystemic autoimmune disease with an unknown etiology. Recently, it has been elucidated that dysregulated histone deacetylase (HDAC) activity is related to the pathogenesis of inflammatory and autoimmune diseases. Broad-spectrum HDAC inhibitors are effective for the treatment of allergy, cancer, and autoimmune diseases, but they have several adverse side effects. Thus, the purpose of this study was to evaluate the effects of a novel HDAC 6-specific inhibitor, CKD-506, in a murine SLE model. CKD-506 significantly improved survival rate and significantly decreased the incidence of severe proteinuria, blood urea nitrogen, kidney inflammation, and glomerular infiltration of IgG and C3. In addition, CKD 506 reduced the proportions of CD138⁺ plasma cells, CD4⁻CD8⁻ T cells, and CD25⁺ cells and the Th1/Th2 ratio in the spleen. CKD-506 significantly reduced inflammatory cytokines such as IL-10, IL-15, IL-17, TNF-α, and IFN-inducible protein (IP-10) and significantly increased TGF-β in serum. CKD-506 also significantly reduced IFN-γ, IL-1β, IL-4, IL-6, IP-10, MCP-1, and CCL4 levels in kidney. CKD-506 decreased the production of various pro-inflammatory cytokines and chemokines in the serum and kidneys, resulting in inhibition of cell migration and suppression of lupus nephritis without adverse effects.

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 receptor 5 (CCR5) delta 32 polymorphism in lupus nephritis: a large case-control study and meta-analysis

OBJECTIVES

Recent animal experiments showed that CCR5-deficient lupus mice (CCR5(-/-)) were closely associated with aggravated lupus nephritis. CCR5 Δ32 variation, a nonsynonymous mutation of CCR5, resulted in altered CCR5 function. However, the CCR5 Δ32 mutation in human lupus nephritis has been rarely reported in the literature.

METHODS

A large case-control study that included 2010 samples from a Chinese population was conducted, followed by a meta-analysis combining the current and previously published studies to explore the effect of CCR5 Δ32 on lupus nephritis susceptibility.

RESULTS

Four CCR5 Δ32 heterozygote carriers were detected in lupus nephritis patients only. We detected no CCR5 Δ32 homozygotes in our study population. In the meta-analysis, including 1,092 cases and 2,229 controls, we found great heterogeneity between studies (p < 0.001, I(2)( )= 89.6%). Furthermore, stratified and sensitivity analyses suggested that ethnicity and CCR5 Δ32 allele frequency were the main origin of heterogeneity. In the subgroups without obvious heterogeneity, we observed a positive correlation between CCR5 Δ32 and lupus nephritis risk (p < 0.05).

CONCLUSIONS

Our study confirmed that the CCR5 Δ32 mutation is a very rare variation found in the Chinese population with Han ethnicity. However, CCR5 Δ32 might play a role in lupus nephritis susceptibility. Future replications and functional studies are needed.

CCR1 inhibition ameliorates the progression of lupus nephritis in NZB/W mice

Systemic lupus erythematosus is a chronic inflammatory autoimmune disease, the development of which is characterized by a progressive loss of renal function. Such dysfunction is associated with leukocyte infiltration in the glomerular and tubulointerstitial compartments in both human and experimental lupus nephritis. In this study, we investigated the role of the Ccr1 chemokine receptor in this infiltration process during the progression of nephritis in the lupus-prone New Zealand Black/New Zealand White (NZB/W) mouse model. We found that peripheral T cells, mononuclear phagocytes, and neutrophils, but not B cells, from nephritic NZB/W mice were more responsive to Ccr1 ligands than the leukocytes from younger prenephritic NZB/W mice. Short-term treatment of nephritic NZB/W mice with the orally available Ccr1 antagonist BL5923 decreased renal infiltration by T cells and macrophages. Longer Ccr1 blockade decreased kidney accumulation of effector/memory CD4(+) T cells, Ly6C(+) monocytes, and both M1 and M2 macrophages; reduced tubulointerstitial and glomerular injuries; delayed fatal proteinuria; and prolonged animal lifespan. In contrast, renal humoral immunity was unaffected in BL5923-treated mice, which reflected the unchanged numbers of infiltrated B cells in the kidneys. Altogether, these findings define a pivotal role for Ccr1 in the recruitment of T and mononuclear phagocyte cells to inflamed kidneys of NZB/W mice, which in turn contribute to the progression of renal injury.

CCR5-Delta32: implications in SLE development

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease with strong genetic and environmental components. Previous studies have shown increased levels of several chemokines in active SLE. C-C chemokine receptor type 5 (CCR5) is involved in the recruitment of inflammatory cells into tissues, and mechanisms modulating CCR5 expression and function may interfere in SLE development, influencing the clinical course of the disease. The aim of this study was to evaluate the possible association between the CCR5∆32 base-pair deletion polymorphism and SLE disease in a group of Portuguese patients. A total of 219 patients with SLE and 205 healthy individuals were studied. The frequency of CCR5/∆32 heterozygotes was lower in patients with SLE than in controls (8% vs. 15% OR = 0.5162; P = 0.0319), suggesting a protective association between CCR5∆32 allele and SLE. These results highlight the protective role of Th1 cells that express CCR5 in SLE pathogenesis.

Differential expression of functional Fc-receptors and additional immune complex receptors on mouse kidney cells

The precise mechanisms by which circulating immune complexes accumulate in the kidney to form deposits in glomerulonephritis are not well understood. In particular, the role of resident cells within glomeruli of the kidney has been widely debated. Immune complexes have been shown to bind one glomerular cell type (mesangial cells) leading to functional responses such as pro-inflammatory cytokine production. To further assess the presence of functional immunoreceptors on resident glomerular cells, cultured mouse renal epithelial, endothelial, and mesangial cells were treated with heat-aggregated mouse IgG or preformed murine immune complexes. Mesangial and renal endothelial cells were found to bind IgG complexes, whereas glomerular epithelial cell binding was minimal. A blocking antibody for Fc-gamma receptors reduced binding to mesangial cells but not renal endothelial cells, suggesting differential immunoreceptor utilization. RT-PCR and immunostaining based screening of cultured renal endothelial cells showed limited low-level expression of known Fc-receptors and Ig binding proteins. The interaction between mesangial cells and renal endothelial cells and immune complexes resulted in distinct, cell-specific patterns of chemokine and cytokine production. This novel pathway involving renal endothelial cells likely contributes to the predilection of circulating immune complex accumulation within the kidney and to the inflammatory responses that drive kidney injury.

A study on the association of autoantibodies, chemokine, and its receptor with disease activity in systemic lupus erythematosus in North Indian population

Systemic lupus erythematosus (SLE) is a chronic and complex autoimmune disease characterized by the production of autoantibodies against a spectrum of nuclear antigens. RANTES and its receptor CCR5 have been associated with the pathogenesis of SLE. The objective of this study is to analyze autoantibodies (DNA/RNA), allelic distribution of RANTES and the association of levels of RANTES and its receptor CCR5 in SLE patients in North Indian region. The RANTES-403 and RANTES-28 polymorphism in the promoter region of RANTES gene was studied in 80 patients and 80 healthy controls. The levels of chemokine RANTES, its receptor CCR5, anti-dsDNA, and anti-SSA antibodies levels were determined. Disease activity was assessed with the systemic lupus erythematosus disease activity index (SLEDAI) score. All the parameters were studied for statistical analysis by using t test (graph pad prism) and correlation by SPSS data. PCR-RFLP performed showed 28C/C and the 403G/G genotypes in both patients and controls, but no other genotypes such as 28C/G, 28G/G and 403A/G, 403A/A were found. Patients had higher levels of RANTES (1840.48 ± 739.42 vs. 835.44 ± 70.48 pg/ml; P < 0.0001) and its receptor CCR5 expression (26.49 ± 0.16 vs. 24.72 ± 3.02 %; P < 0.05) compared to controls. The levels of autoantibodies anti-dsDNA and anti-SSA were also higher in patients than controls. The patients showing elevated anti-dsDNA had negative correlation with SLEDAI score (P < 0.05) while borderline patients were not found to be correlated. In case of anti-Ro/anti-SSA antibody levels, the borderline patients showed a moderately significant negative correlation as compared to controls than patients with elevated autoantibody (P < 0.01). The levels of RANTES and CCR5 were also higher in case of patients than controls. But there was no significant correlation of RANTES and CCR5 with disease activity. We were unable to find an association of RANTES polymorphism with SLE in North Indian population in our sample. No significant difference in allele distribution of RANTES-28 and RANTES-403 in the sample of 160 individuals was detected. Of the two autoantibodies studied, anti-Ro/anti-SSA levels in borderline lupus patients appeared as an important parameter for monitoring/diagnosis of lupus patients.

Association of RANTES and MBL gene polymorphisms with systemic lupus erythematosus: a meta-analysis

The RANTES (regulated on activation normal T cell expressed and secreted) and MBL (mannose binding lectin) single-nucleotide polymorphisms have been repeatedly associated with systemic lupus erythematosus (SLE), but the findings are not consistent across studies. The aim of this study was to determine whether the functional RANTES-28, -403 and MBL2 A/O polymorphisms confer susceptibility to SLE in multiple ethnic populations. A meta-analysis was conducted (allelic contrast, the additive model, the dominant model and the recessive model) on RANTES with seven studies (four studies for RANTES-28: three Asian and one American studies; three studies for RANTES-403: two Asian and one European studies), MBL with eight studies (five European and three American studies). OR is used as a measure of the effect of the association in a fixed/random effects model. The meta-analysis indicated that none of the two polymorphisms in gene of the RANTES showed any significant association with SLE risk, respectively, except for the recessive model (OR = 1.24, 95 % CI: 1.01-1.52, P = 0.04) in all study subjects combined with the two polymorphisms. According to the MBL2 A/O polymorphism, the results indicated a significant association between the polymorphism and SLE in allelic contrast (OR = 0.83, 95 % CI: 0.73-0.93, P = 0.002). While stratified by ethnicity in European, no significant association was found. In summary, the present study suggests that the RANTES-28, -403 polymorphisms do not associate with SLE, but the MBL2 A/O polymorphism might associate with SLE.

Immunotherapy for acute kidney injury

Acute renal failure, now referred to as acute kidney injury, is a common and clinically important problem. Acute kidney injury frequently occurs as a result of acute tubular necrosis (ATN), which is often caused by a reduction in systemic blood pressure or renal blood flow (e.g., as observed in severe sepsis or during renal transplantation). The disease course in ATN is variable, including prolonged dialysis-dependence and chronic renal dysfunction, but there is currently no specific therapy for ATN. There is increasing evidence that the inflammatory response in ATN significantly contributes to disease severity and outcome. In this review, we summarize recent developments in the understanding of how the immune system responds to dying cells, and the relevance of these discoveries to ATN. In particular, NLRP3 inflammasome activation and IL-1β-mediated neutrophil recruitment are likely to play a key role and may provide novel therapeutic targets for immunotherapy in ATN.

Serum from patients with SLE instructs monocytes to promote IgG and IgA plasmablast differentiation

Monocytes exposed to serum from SLE patients promote B cell differentiation to IgG and IgA plasmablasts dependent on BAFF and IL-10 or APRIL, respectively.

The development of autoantibodies is a hallmark of systemic lupus erythematosus (SLE). SLE serum can induce monocyte differentiation into dendritic cells (DCs) in a type I IFN–dependent manner. Such SLE-DCs activate T cells, but whether they promote B cell responses is not known. In this study, we demonstrate that SLE-DCs can efficiently stimulate naive and memory B cells to differentiate into IgG- and IgA-plasmablasts (PBs) resembling those found in the blood of SLE patients. SLE-DC–mediated IgG-PB differentiation is dependent on B cell–activating factor (BAFF) and IL-10, whereas IgA-PB differentiation is dependent on a proliferation-inducing ligand (APRIL). Importantly, SLE-DCs express CD138 and trans-present CD138-bound APRIL to B cells, leading to the induction of IgA switching and PB differentiation in an IFN-α–independent manner. We further found that this mechanism of providing B cell help is relevant in vivo, as CD138-bound APRIL is expressed on blood monocytes from active SLE patients. Collectively, our study suggests that a direct myeloid DC–B cell interplay might contribute to the pathogenesis of SLE.

Protective role for CCR5 in murine lupus nephritis

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- Faslpr (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.

Lupus nephritis: an overview of recent findings

Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE) since it is the major predictor of poor prognosis. In susceptible individuals suffering of SLE, in situ formation and deposit of immune complexes (ICs) from apoptotic bodies occur in the kidneys as a result of an amplified epitope immunological response. IC glomerular deposits generate release of proinflammatory cytokines and cell adhesion molecules causing inflammation. This leads to monocytes and polymorphonuclear cells chemotaxis. Subsequent release of proteases generates endothelial injury and mesangial proliferation. Presence of ICs promotes adaptive immune response and causes dendritic cells to release type I interferon. This induces maturation and activation of infiltrating T cells, and amplification of Th2, Th1 and Th17 lymphocytes. Each of them, amplify B cells and activates macrophages to release more proinflammatory molecules, generating effector cells that cannot be modulated promoting kidney epithelial proliferation and fibrosis. Herein immunopathological findings of LN are reviewed.

Chemokines in renal injury

The main function of chemokines is to guide inflammatory cells in their migration to sites of inflammation. During the last 2 decades, an expanding number of chemokines and their receptors have driven broad inquiry into how inflammatory cells are recruited in a variety of diseases. Although this review focuses on chemokines and their receptors in renal injury, proinflammatory IL-17, TGFβ, and TWEAK signaling pathways also play a critical role in their expression. Recent studies in transgenic mice as well as blockade of chemokine signaling by neutralizing ligands or receptor antagonists now allow direct interrogation of chemokine action. The emerging role of regulatory T cells and Th17 cells during renal injury also forges tight relationships between chemokines and T cell infiltration in the development of kidney disease. As chemokine receptor blockade inches toward clinical use, the field remains an attractive area with potential for unexpected opportunity in the future.

RANTES deficiency attenuates autoantibody-induced glomerulonephritis

Experimental autoimmune nephritis in mice and spontaneous lupus nephritis are both associated with elevated expression of several chemokines in the kidneys. Nevertheless, the role that different chemokines play in mediating renal inflammation is far from complete. This study focuses on elucidating the functional role of RANTES, a chemokine that has been noted to be hyper-expressed within the kidneys, both in experimental renal disease as well as in spontaneous lupus nephritis. To elucidate if RANTES was essential for immune-mediated glomerulonephritis, DBA/1 mice that are highly sensitive to nephrotoxic serum nephritis were rendered RANTES-deficient and then tested for disease susceptibility. Nephritis-sensitive DBA/1 mice expressed more RANTES within the diseased kidneys. Compared to wild-type DBA/1 mice, RANTES-deficient DBA/1 mice developed significantly less proteinuria, azotemia, and renal inflammation, with reduced crescent formation and tubulo-interstitial nephritis. These findings indicate that RANTES ablation attenuates immune-mediated nephritis and suggest that this chemokine could be a potential therapeutic target in these diseases.

Chemokine receptor CCR1 regulates inflammatory cell infiltration after renal ischemia-reperfusion injury

Neutrophils and macrophages rapidly infiltrate the kidney after renal ischemia-reperfusion injury, however specific molecular recruitment mechanisms have not been fully delineated for these cell types. Here we provide genetic and pharmacologic evidence supporting a positive role for the chemokine receptor CCR1 in macrophage and neutrophil infiltration in a 7 day mouse model of renal ischemia-reperfusion injury. By day 7, injured kidneys from mice lacking CCR1 contained 35% fewer neutrophils and 45% fewer macrophages than injured kidneys from wild-type control mice. Pretreatment of wild-type mice with the specific CCR1 antagonist BX471 also suppressed neutrophil and macrophage infiltration in the model. Injured kidneys from mice lacking CCR1 also had reduced content of the CCR1 ligands CCL3 (MIP-1alpha) and CCL5 (RANTES) compared with injured kidneys from wild-type controls, suggesting a leukocyte source for these inflammatory chemokines and existence of a CCR1-dependent positive feedback loop for leukocyte infiltration in the model. Local leukocyte proliferation and apoptosis were detected after injury, but were not dependent on CCR1. Also, the extent of necrotic and fibrotic damage and decline in renal function in injured kidneys was similar in wild-type and CCR1-deficient mice. Thus, CCR1 appears to regulate trafficking of macrophages and neutrophils to kidney in a mouse model of renal ischemia-reperfusion injury, however this activity does not appear to affect tissue injury.

CCL3L1 gene-containing segmental duplications and polymorphisms in CCR5 affect risk of systemic lupus erythaematosus

OBJECTIVES

There is an enrichment of immune response genes that are subject to copy number variations (CNVs). However, there is limited understanding of their impact on susceptibility to human diseases. CC chemokine ligand 3 like-1 (CCL3L1) is a potent ligand for the HIV coreceptor, CC chemokine receptor 5 (CCR5), and we have demonstrated previously an association between CCL3L1-gene containing segmental duplications and polymorphisms in CCR5 and HIV/AIDS susceptibility. Here, we determined the association between these genetic variations and risk of developing systemic lupus erythaematosus (SLE), differential recruitment of CD3+ and CD68+ leukocytes to the kidney, clinical severity of SLE reflected by autoantibody titres and the risk of renal complications in SLE.

METHODS

We genotyped 1084 subjects (469 cases of SLE and 615 matched controls with no autoimmune disease) from three geographically distinct cohorts for variations in CCL3L1 and CCR5.

RESULTS

Deviation from the average copy number of CCL3L1 found in European populations increased the risk of SLE and modified the SLE-influencing effects of CCR5 haplotypes. The CCR5 human haplogroup (HH)E and CCR5-Delta32-bearing HHG*2 haplotypes were associated with an increased risk of developing SLE. An individual's CCL3L1-CCR5 genotype strongly predicted the overall risk of SLE, high autoantibody titres, and lupus nephritis as well as the differential recruitment of leukocytes in subjects with lupus nephritis. The CCR5 HHE/HHG*2 genotype was associated with the maximal risk of developing SLE.

CONCLUSION

CCR5 haplotypes HHE and HHG*2 strongly influence the risk of SLE. The copy number of CCL3L1 influences risk of SLE and modifies the SLE-influencing effects associated with CCR5 genotypes. These findings implicate a key role of the CCL3L1-CCR5 axis in the pathogenesis of SLE.

Estrogen and CD4+ T cells

PURPOSE OF REVIEW

Many autoimmune rheumatic autoimmune disorders predominantly affect women. Sex hormones, in particular estrogen, can influence CD4 T-helper development and function. We highlight recent studies that begin to provide insights into the mechanisms by which estrogen modulates CD4 T-cell development and function, and thus potentially contribute to disease pathogenesis.

RECENT FINDINGS

High levels of estrogen can lead to thymic atrophy. Recent studies showed that this phenomenon results from effects of estrogen at multiple stages in early T-cell development. Estrogen is also known to affect mature CD4 T-cell function, and, in particular, their ability to produce selected cytokine profiles. The mechanisms by which estrogen can exert these effects were also recently explored and shown to include effects on expression of critical molecules known to be involved in these processes.

SUMMARY

Dissecting the molecular pathways employed by estrogen to modulate CD4 T cells will be critical in elucidating the manner by which estrogen exerts its effects on this compartment. Given that cell type specific differences underlie the ability of many hormonal therapies to exert tissue-specific estrogenic or antiestrogenic activities, this knowledge will be crucial to further exploitation of hormonal therapies in rheumatic autoimmune diseases.

Mechanisms of disease: regulation of RANTES (CCL5) in renal disease

Chemokines (chemoattractant cytokines) are fundamental regulators of immune cell movement from the bloodstream into tissues. Regulating expression of chemokines might, therefore, alleviate inflammation in autoimmune diseases and transplant rejection, or augment immune responses in cancer and immunodeficiency. RANTES (regulated upon activation, normal T cell expressed and secreted [also known as CCL5]) is a model chemokine of relevance to a myriad of diseases. Regulation of RANTES expression is complex. In fibroblasts and monocytes, rel proteins alone suffice to induce transcription of RANTES. By contrast, expression of RANTES in T lymphocytes 3-5 days after activation requires the development of a molecular complex (enhancesome) including KLF13 (Krueppel-like factor 13), rel proteins p50 and p65, and scaffolding proteins. This complex recruits enzymes involved in acetylation, methylation and phosphorylation of chromatin, and ultimately in the expression of RANTES. In addition, KLF13-the lynchpin for recruitment of this molecular complex-is itself translationally regulated. Such complex regulation of biological systems has major implications for the rational design of drugs aimed at increasing or decreasing inflammatory responses in patients.

Cognate chemokine receptor 1 messenger ribonucleic acid expression in peripheral blood as a diagnostic test for endometriosis

We investigated the expression of the cognate chemokine receptor 1 (CCR1) messenger ribonucleic acid, a G-protein-coupled cognate chemokine receptor with high affinity for RANTES (Regulated upon Activation, Normal T cells Expressed and Secreted), in peripheral blood leukocytes of women with and without endometriosis, and its potential use as a diagnostic test for endometriosis. Because patients with an earlier diagnosis of this disease have a better treatment outcome and a reduced recurrence rate, CCR1 mRNA measurement in the peripheral blood of patients with suspected endometriosis might give us a new perspective in diagnosing and treating this disease earlier and better.

RANTES mediates TNF-dependent lamina propria mast cell accumulation and barrier dysfunction in neurogenic cystitis

Barrier dysfunction of the urinary bladder is postulated to contribute to patient morbidity in the bladder inflammatory disease interstitial cystitis (IC). IC is often considered a neurogenic cystitis, but the mechanisms underlying barrier dysfunction are unclear. In murine neurogenic cystitis induced by pseudorabies virus (PRV), we previously observed formation of urothelial lesions characterized by urothelial apoptosis and urothelial discontinuities. Lesion formation was preceded by mast cell trafficking to the lamina propria, and trafficking was mediated by tumor necrosis factor-alpha (TNF). Here, we found that supernatants of TNF-treated urothelial cultures promoted chemotaxis of bone marrow-derived mast cells in vitro that was blocked by anti-RANTES antibodies but unaffected by anti-TNF antibodies. In vivo, PRV infection of wild-type mice induced RANTES expression in the urothelium that was temporally coincident with lamina propria mast cell accumulation (maximum at days 3-4 following infection) and was not induced in TNF(-/-) mice, TNFR1/2(-/-) mice, or mice treated with anti-TNF antibodies. Anti-RANTES antibodies blocked PRV-induced lamina propria mast cell accumulation 56% and reduced the prevalence of animals with detectable lesions 42%, relative to isotype control antibodies. Bladder barrier function was quantified by measuring transepithelial resistance (TER). PRV induced a 49% loss of TER in the presence of control antibodies, but mice treated with anti-RANTES antibodies exhibited reduced TER loss (16%, P < 0.01). These data demonstrate that RANTES plays a key role in the pathogenesis of neurogenic cystitis and suggest that chemokines may represent novel therapeutic targets for IC patients with mast cell-associated disease.

Chemokines and Chemokine Receptors as Therapeutic Targets in Lupus Nephritis

Recruitment of leukocytes is a characteristic feature of tissue injury in systemic lupus erythematosus, including lupus nephritis. Locally secreted chemokines and their receptors are important mediators of leukocyte recruitment to the specific sites of immune complex injury, and contribute to renal inflammatory disease in the initiation and progression phase. Therefore, chemokines and chemokine receptors represent potential therapeutic targets in lupus nephritis. In this review we summarize available experimental and human data supporting their functional role in lupus nephritis. Moreover, interventional studies with chemokine and chemokine receptor antagonists that show the therapeutic potential of chemokine antagonists in experimental models of lupus nephritis and potentially in human renal disease are discussed.

Messenger RNA expression of RANTES in the urinary sediment of patients with lupus nephritis

BACKGROUND

Lupus nephritis is characterized by intra-renal inflammation. Patients with systemic lupus erythematosus (SLE) showed abnormal T-cell expression of RANTES (regulated upon activation, normal T cell expressed) and its level in their serum. The authors studied the mRNA expression of RANTES in the urinary sediment of lupus patients.

METHODS

The authors studied 88 lupus patients, who were classified into active, remission and non-renal SLE groups according to the disease activity, 29 non-SLE and 10 healthy controls. Lupus activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Urinary mRNA expression of RANTES was studied by real-time quantitative polymerase chain reaction.

RESULTS

The expression of RANTES in urinary sediment was significantly elevated in active group (P < 0.001). Expression level of RANTES correlated with the SLEDAI score (r = 0.57; P < 0.001) and renal score in SLEDAI (r = 0.60; P < 0.001). In addition, urinary expression of RANTES had significant correlation with degree of proteinuria, serum creatinine, albumin and estimated glomerular filtration rate.

CONCLUSION

The authors conclude that the mRNA expression of RANTES was elevated in the urinary sediment of patients with active lupus nephritis. Measurement of urinary mRNA expression may be a novel non-invasive method for the assessment of lupus disease activity and the severity of renal involvement.

TAK-603, an anti-inflammatory compound, reduces crescentic glomerulonephritis and preserves renal function in WKY rats

BACKGROUND

The therapeutic efficacy of the regulation of T helper (Th)-1-predominant immune responses remains to be investigated. Therefore, the effects of the anti-inflammatory compound TAK-603 were investigated in a model of crescentic glomerulonephritis induced by a small dose of nephrotoxic serum in Wistar-Kyoto rats.

METHODS

TAK-603 (50 mg/kg body weight) was administered orally, starting at the time of induction of glomerulonephritis. In group 1, the drug was administered daily for the initial 6 days. TAK-603 was administered on day 0 only in group 2, and from day 3 to 5 in group 3. In each group, nephritic rats were killed on days 6 and 56.

RESULTS

In group 1 consisting of rats treated with TAK-603 daily from day 0 to 5, glomerular damage, including crescent formation, was improved on day 6, with reductions in the numbers of CD4, CD8 and ED-1 positive cells, as well as in urinary protein excretion. Protein and transcript levels of Th1 cytokines in the diseased kidneys were markedly decreased by TAK-603 treatment. Renal pathology, including glomerulosclerosis and interstitial fibrosis, was ameliorated and proteinuria was markedly decreased. Elevated levels of serum creatinine showed concomitant improvement. In group 3, in which treatment was initiated shortly after the appearance of glomerular abnormalities, glomerular damage was also diminished, resulting in a decrease in urinary protein excretion. Treatment only on the first day in group 2, partially rescued renal dysfunction.

CONCLUSIONS

These results suggest the possible therapeutic application of inhibition of Th1-predominant immune responses in progressive crescentic glomerulosclerosis.

Increase of expression and activation of chemokine CCL15 in chronic renal failure

Chemokines are believed to be involved in the pathogenesis of chronic renal failure (CRF). In CRF, significantly increased CCL15-IR plasma concentrations were detected. Whereas in plasma of healthy individuals one predominant CCL15-IR molecule with a M(w) of 15kDa [high molecular weight (HMW-CCL15-IR)] was identified, CRF plasma contains increased concentrations of truncated CCL15-IR molecules [intermediate molecular weight (IMW-CCL15-IR)]. HMW-CCL15-IR isolated from hemofiltrate revealed an M(w) of 10141.3, corresponding to deglycosylated CCL15(1-92) carrying a N-terminal pyrrolidone carboxylic acid. CCL15(12-92) was identified as a major component of IMW-CCL15-IR in CRF plasma. Compared to CCL15(1-92), in monocytes CCL15(12-92) causes stronger induction of intracellular calcium flux, chemotactic activity, and adhesion to fibronectin. Intracellular calcium flux assays revealed that, in comparison to peripheral blood mononuclear cells (PBMC) of healthy donors, PBMCs of CRF patients demonstrated an increased sensitivity to CCL15. Our results point to an involvement of the CCL15-CCR1 axis in the pathophysiology of CRF.

T cells in crescentic glomerulonephritis

Crescent formation in glomerulonephritis (GN) is a manifestation of severe glomerular injury that usually results in a poor clinical outcome. In humans, crescentic GN is frequently associated with evidence of either systemic or organ-specific autoimmunity. T cells play a major role in initiation of adaptive immune responses that lead to crescentic injury. In experimental models of crescentic GN, Th1 predominant immune responses have been shown to promote crescent formation. Perturbation of regulatory T cell function may contribute to development of autoimmune crescentic GN. The presence of T cells and macrophages in crescentic glomeruli, frequently in the absence of humoral mediators of immunity, suggest a dominant effector role for T cells in crescentic GN. The association of cellular immune mediators with local fibrin deposition implicates cell-mediated "delayed-type hypersensitivity-like" mechanisms in crescent formation. Intrinsic renal cells also contribute to T cell-driven effector mechanisms in crescentic GN, via expression of MHC II and co-stimulatory molecules and by production of chemokines and cytokines that amplify leukocyte recruitment and injury.

Conditional ablation of macrophages halts progression of crescentic glomerulonephritis

The presence of macrophages in inflamed glomeruli of rat kidney correlates with proliferation and apoptosis of resident glomerular mesangial cells. We assessed the contribution of inflammatory macrophages to progressive renal injury in murine crescentic glomerulonephritis (GN). Using a novel transgenic mouse (CD11b-DTR) in which tissue macrophages can be specifically and selectively ablated by minute injections of diphtheria toxin, we depleted renal inflammatory macrophages through days 15 and 20 of progressive crescentic GN. Macrophage depletion reduced the number of glomerular crescents, improved renal function, and reduced proteinuria. Morphometric analysis of renal tubules and interstitium revealed a marked attenuation of tubular injury that was associated with reduced proliferation and apoptosis of tubular cells. The population of interstitial myofibroblasts decreased after macrophage depletion and interstitial fibrosis also decreased. In the presence of macrophages, interstitial myofibroblasts exhibited increased levels of both proliferation and apoptosis, suggesting that macrophages act to support a population of renal myofibroblasts in a high turnover state and in matrix deposition. Finally, deletion of macrophages reduced CD4 T cells in the diseased kidney. This study demonstrates that macrophages are key effectors of disease progression in crescentic GN, acting to regulate parenchymal cell populations by modulating both cell proliferation and apoptosis.

Progression of kidney disease: Blocking leukocyte recruitment with chemokine receptor CCR1 antagonists

Chronic kidney disease (CKD) is usually associated with interstitial leukocytic cell infiltrates, which may contribute to disease progression by production of proinflammatory, proapoptotic, and profibrotic mediators. Recruiting leukocytes into the kidney involves local expression of chemotactic cytokines, that is, chemokines, that interact with respective chemokine receptors on the leukocyte's outer surface. Thus, specific chemokine receptor antagonists may represent an attractive therapeutic concept to interfere with renal leukocyte recruitment. Among the proinflammatory chemokine receptors, chemokine receptor (CCR)-1 has nonredundant roles for leukocyte adhesion to activated vascular endothelium and for transendothelial migration. In fact, blocking CCR-1 with specific small-molecule antagonists was shown to retard progression in various types of rodent CKD models. Here we discuss the perspective of CCR-1 as a new potential target for the treatment of CKD.

Glomerulonephritis, Th1 and Th2: what's new?

Glomerulonephritis (GN), the major worldwide cause of chronic renal disease and renal failure, shows a wide spectrum of histological patterns, severity of injury and clinical outcomes that may be related to the nature of the nephritogenic immune response. In the majority of cases, there is evidence of a central role for cognate immunity in the initiation of human GN and contributions of both humoral and cellular effector mechanisms have been demonstrated in both humans and in animal models. T helper cell subsets are known to activate different immune effector mechanisms which influence disease outcomes in infectious and autoimmune diseases and evidence is now accumulating that Th1 and Th2 subsets direct diverging effector pathways that lead to different patterns and severity of glomerular injury in GN. Th1-predominant responses appear to be associated strongly with proliferative and crescentic forms of GN that result in severe renal injury, while Th2 responses are associated with membranous patterns of injury. The challenge remains to understand fully the relevance of T helper cell subset responses to the spectrum of human GN and to apply this new knowledge to the development of more potent and selective therapeutic strategies.

Macrophages and progressive tubulointerstitial disease

Macrophages and progressive tubulointerstitial disease. In chronic renal disease, tubulointerstitial inflammation and injury is associated with infiltrating macrophages. As a consequence of primary injury, proteinuria, chronic hypoxia, and glomerular-derived cytokines may all differentially modulate the expression of factors that promote macrophage recruitment. In addition to adhesion molecules and chemokines, products of complement system and renin-angiotensin system activation may direct this process. Once present at interstitial sites, macrophages interact with resident cells and extracellular matrix to generate a proinflammatory microenvironment that amplifies tissues injury and promotes scarring. There is now increasing evidence for the efficacy of interventions directed against factors that recruit, activate, or are produced by macrophages. A detailed understanding of the biology of this area may lead to the further development of therapies that will improve the outcome of renal disease.

Kidneys with heavy proteinuria show fibrosis, inflammation, and oxidative stress, but no tubular phenotypic change

BACKGROUND

Sustained proteinuria is a major factor leading to kidney fibrosis and end-stage renal failure. Tubular epithelial cells are believed to play a crucial role in this process by producing mediators leading to fibrosis and inflammation. Congenital nephrotic syndrome of the Finnish type (NPHS1) is a genetic disease caused by mutations in a podocyte protein nephrin, which leads to constant heavy proteinuria from birth. In this work we studied the tubulointerstitial changes that occur in NPHS1 kidneys during infancy.

METHODS

The pathologic lesions and expression of profibrotic and proinflammatory factors in nephrectomized NPHS1 kidneys were studied by immunohistochemistry, Western blotting, and cytokine antibody array. Oxidative stress in kidneys was assessed by measurement of gluthatione redox state.

RESULTS

The results indicated that (1) severe tubulointerstitial lesions developed in NPHS1 kidneys during infancy; (2) tubular epithelial cells did not show transition into myofibroblasts as studied by the expression of vimentin, alpha-smooth muscle actin (alpha-SMA), collagen, and matrix metalloproteinases 2 and 9 (MMP-2 and -9); (3) the most abundant chemokines in NPHS1 tissue were neutrophil activating protein-2 (NAP-2), macrophage inhibiting factor (MIF), and monocyte chemoattractant protein-1 (MCP-1); (4) monocyte/macrophage cells expressing CD14 antigen were the major inflammatory cells invading the interstitium; (5) the arteries and arterioles showed intimal hypertrophy, but the microvasculature in NPHS1 kidneys remained quite normal; and (6) excessive oxidative stress was evident in NPHS1 kidneys.

CONCLUSION

Heavy proteinuria in NPHS1 kidneys was associated with interstitial fibrosis, inflammation, and oxidative stress. The tubular epithelial cells, however, were resistant to proteinuria and did not show epithelial-mesenchymal transition.

C-C Chemokine Receptor 5 Gene Variants in Relation to Lung Disease in Sarcoidosis

RATIONALE

Genetic factors are likely to influence the clinical course and pattern of sarcoidosis, a granulomatous disease of unknown origin.

OBJECTIVES

We tested this hypothesis for C-C chemokine receptor 5 (CCR5), a molecule involved in recruitment and activation of mononuclear cells.

METHODS

In addition to the known CCR5 Delta 32 insertion/deletion, we evaluated a further eight single-nucleotide polymorphisms in 106 British patients and 142 British unaffected subjects, and second-setted the results in 112 Dutch patients and 169 healthy Dutch control subjects.

MEASUREMENTS AND MAIN RESULTS

In the British population, the frequency of one of the identified haplotypes (HHC) was strongly associated with the presence of parenchymal disease (radiographic stage >or= II versus stages 0 and I) at presentation (odds ratio [OR], 5.2; 95% confidence interval [CI], 1.96-13.7; corrected p = 0.02), at 2 (OR, 6.6; 95% CI, 2.5-17.6; corrected p = 0.006), and at 4 years follow-up (OR, 6.8; 95% CI, 2.5-18.0; corrected p = 0.0045). In the Dutch population, the same association was seen at 2 (OR, 6.7; 95% CI, 2.8-16.4; corrected p = 0.002), and 4 years follow-up (OR, 9.0; 95% CI, 3.5-23.1; corrected p = 0.0009).

CONCLUSIONS

No association between the CCR5 haplotype HHC and susceptibility to sarcoidosis was observed, indicating that this relevant gene only operates after disease induction. In summary, we report a strong association between CCR5 haplotype HHC and persistent lung involvement in sarcoidosis.

Chemokine receptor CCR1: a new target for progressive kidney disease

Infiltrating leukocytes are thought to contribute to the progression of kidney disease. Locally produced chemokines guide circulating leukocytes into the kidney, which renders therapeutic blockade of respective chemokine receptors on the leukocyte surface as potential targets for the inhibition of renal leukocyte recruitment. By using mutant mice and specific antagonists, we found that chemokine receptor CCR1 has non-redundant functions for leukocyte adhesion to activated vascular endothelium and for transendothelial diapedesis. Most importantly, CCR1 blockade with a specific small molecule antagonist can improve injury in several types of progressive kidney disease models, even if treatment is initiated in advanced disease states. Identification of new targets may add to the therapeutic options in chronic kidney disease.

Expression and regulation of CCR1 in peritoneal macrophages from women with and without endometriosis

CCR1 is a CC chemokine receptor with high affinity for RANTES (regulated upon activation, normal T cells expressed and secreted). CCR1 protein and mRNA concentrations in native peritoneal cells were twofold greater, in cultured peritoneal cells threefold greater, in patients with endometriosis compared to patients without endometriosis, as determined by Western blotting fluorescence activated cell sorting analysis, reverse transcription-polymerase chain reaction, and in situ hybridization.

CCR1 blockade reduces interstitial inflammation and fibrosis in mice with glomerulosclerosis and nephrotic syndrome

BACKGROUND

CC chemokines mediate leukocyte infiltration into inflamed tissue. We have recently shown that blockade of the CC chemokine receptor CCR1 reduces interstitial inflammation and fibrosis in murine obstructive nephropathy. However, it is not known whether CCR 1 blockade is protective in progressive renal injury associated with severe proteinuria. We therefore studied the effect of the small-molecule CCR1 antagonist BX471 in a murine model of adriamycin-induced focal segmental glomerulosclerosis (FSGS) with nephrotic syndrome and progressive interstitial inflammation and fibrosis.

METHODS

Adriamycin nephropathy with persistent proteinuria was induced in male BALB/c mice by two intravenous injections of adriamycin (13 mg/kg) at day 0 and 14. BX471 treatment was started at day 14 when proteinuria and interstitial inflammation had developed. At 6 weeks, renal histology was studied by morphometry and immunohistochemistry.

RESULTS

At week 6, adriamycin-treated mice showed FSGS, associated with tubulointerstitial injury consisting of tubular dilation and atrophy, interstitial leukocyte infiltration, and fibrosis. The mRNA expression of CCR1 and CC chemokines, including the CCR1 ligands CCL3 (MIP-1alpha) and CCL5 (RANTES), was up-regulated in diseased kidneys, with a prominent interstitial expression of CCL5. Compared to vehicle-treated controls BX471 significantly reduced the amount of macrophages and T lymphocytes in interstitial lesions by 51% and 22%, respectively. Markers of renal fibrosis such as interstitial fibroblasts (48%) and interstitial volume (23%) were significantly reduced by BX471 treatment. In contrast, the extent of proteinuria and glomerular sclerosis was not affected by BX471 treatment.

CONCLUSION

Blockade of CCR1 substantially reduced interstitial leukocyte accumulation and the subsequent renal fibrosis in a murine model of nephrotic syndrome and FSGS. These findings support a role for CCR1 in interstitial leukocyte recruitment and suggest that CCR1 blockade might be a new therapeutic strategy in progressive nephropathies such as FSGS.

Involvement of extracellular signal-regulated kinase and p38 in human diabetic nephropathy

BACKGROUND

The involvement of mitogen-activated protein kinase (MAPK) in human diabetic nephropathy has not been fully investigated.

METHODS

The presence of cells positive for the phosphorylated MAPK family (phosphorylated extracellular signal-regulated kinase [p-ERK], phosphorylated p38MAPK [p-p38MAPK]) was investigated immunohistochemically in kidneys of 30 patients with diabetic nephropathy. In addition, 10 patients with minimal change nephrotic syndrome, 10 patients with thin basement membrane disease, and 5 patients with benign nephrosclerosis were studied as disease controls. The presence of activated nuclear factor-kappaB (p65)-positive cells also was evaluated in kidney specimens.

RESULTS

In patients with diabetic nephropathy, p-ERK, p-p38MAPK, and p65 were observed in mesangial cells, endothelial cells, podocytes, tubular epithelial cells, and mononuclear infiltrates in interstitium. Numbers of p-ERK-, p-p38MAPK-, and p65-positive cells in both glomeruli and interstitium in patients with diabetic nephropathy were higher than those in controls. In particular, the number of glomerular p-ERK-positive cells in patients with diabetic nephropathy increased in accordance with the progression of glomerular lesions and correlated well with the number of glomerular p65-positive cells (r = 0.654; P < 0.01; n = 30). Conversely, the number of p-p38MAPK-positive cells in glomeruli did not correlate with glomerular lesions. However, the number of tubulointerstitial p-p38MAPK-positive cells in patients with diabetic nephropathy reflected the severity of tubulointerstitial lesions, and numbers of those in the interstitium increased with good correlation to numbers of tubulointerstitial p65-positive cells (r = 0.757; P < 0.01; n = 30) and interstitial CD68-positive macrophages (r = 0.647; P < 0.05; n = 30) and urinary monocyte chemoattractant protein-1 levels (r = 0.605; P < 0.05; n = 30).

CONCLUSION

These results suggest that MAPK phosphorylation contributes to human diabetic nephropathy. In particular, ERK and p38MAPK may be distinctly involved in glomerular and tubulointerstitial lesions in human diabetic nephropathy.

Multiple facets of macrophages in renal injury

Macrophage infiltration is a common feature of renal disease and their presence has been synonymous with tissue damage and progressive renal failure. More recently work has focused on the heterogeneity of macrophage activation and in particular their ability to curtail inflammation and restore normal function. This has led to the view that it is macrophage function rather than their number that is important in determining the outcome of inflammatory disease. This review will focus on the pathways that regulate macrophage infiltration and activation and how these could be manipulated to control renal inflammatory disease. In particular, the ability of specific cell surface receptors and intracellular signaling pathways to control macrophage activation and how macrophages can be genetically manipulated to develop properties that favor resolution over ongoing injury.

Identifying Chemokines as Therapeutic Targets in Renal Disease: Lessons from Antagonist Studies and Knockout Mice

Chemokines, in concert with cytokines and adhesion molecules, play multiple roles in local and systemic immune responses. In the kidney, the temporal and spatial expression of chemokines correlates with local renal damage and accumulation of chemokine receptor-bearing leukocytes. Chemokines play important roles in leukocyte trafficking and blocking chemokines can effectively reduce renal leukocyte recruitment and subsequent renal damage. However, recent data indicate that blocking chemokine or chemokine receptor activity in renal disease may also exacerbate renal inflammation under certain conditions. An increasing amount of data indicates additional roles of chemokines in the regulation of innate and adaptive immune responses, which may adversively affect the outcome of interventional studies. This review summarizes available in vivo studies on the blockade of chemokines and chemokine receptors in kidney diseases, with a special focus on the therapeutic potential of anti-chemokine strategies, including potential side effects, in renal disease.