TNF alpha induces expression of the chemoattractant cytokine RANTES in cultured mouse mesangial cells

Prenatal arsenic exposure induces immunometabolic alteration and renal injury in rats

Arsenic (As) exposure is progressively associated with chronic kidney disease (CKD), a leading public health concern present worldwide. The adverse effect of As exposure on the kidneys of people living in As endemic areas have not been extensively studied. Furthermore, the impact of only prenatal exposure to As on the progression of CKD also has not been fully characterized. In the present study, we examined the effect of prenatal exposure to low doses of As 0.04 and 0.4 mg/kg body weight (0.04 and 0.4 ppm, respectively) on the progression of CKD in male offspring using a Wistar rat model. Interestingly, only prenatal As exposure was sufficient to elevate the expression of profibrotic (TGF-β1) and proinflammatory (IL-1α, MIP-2α, RANTES, and TNF-α) cytokines at 2-day, 12- and 38-week time points in the exposed progeny. Further, alteration in adipogenic factors (ghrelin, leptin, and glucagon) was also observed in 12- and 38-week old male offspring prenatally exposed to As. An altered level of these factors coincides with impaired glucose metabolism and homeostasis accompanied by progressive kidney damage. We observed a significant increase in the deposition of extracellular matrix components and glomerular and tubular damage in the kidneys of 38-week-old male offspring prenatally exposed to As. Furthermore, the overexpression of TGF-β1 in kidneys corresponds with hypermethylation of the TGF-β1 gene-body, indicating a possible involvement of prenatal As exposure-driven epigenetic modulations of TGF-β1 expression. Our study provides evidence that prenatal As exposure to males can adversely affect the immunometabolism of offspring which can promote kidney damage later in life.

Exploring the pathogenesis of diabetic kidney disease by microarray data analysis

Diabetic kidney disease (DKD) is a major complication of diabetes mellitus, and the leading contributor of end-stage renal disease. Hence, insights into the molecular pathogenesis of DKD are urgently needed. The purpose of this article is to reveal the molecular mechanisms underlying the pathogenesis of DKD. The microarray datasets of GSE30528 and GSE30529 were downloaded from the NCBI Gene Expression Omnibus (GEO) database to identify the common differentially expressed genes (DEGs) between the glomerular DKD (GDKD) and tubular DKD (TDKD), respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed to analyze the function and pathways of the common DEGs. After constructing the protein–protein interaction (PPI) network and subnetwork analysis, three types of analyses were performed, namely, identification of hub genes, analysis of the coexpressed network, and exploration of transcription factors (TFs). Totally, 348 and 463 DEGs were identified in GDKD and TDKD, respectively. Then, 66 common DEGs (63 upregulated DEGs and three downregulated DEGs) were obtained in DKD patients. GO and KEGG pathway analyses revealed the importance of inflammation response, immune-related pathways, and extracellular matrix-related pathways, especially chemokines and cytokines, in DKD. Fifteen hub genes from the 66 common DEGs, namely, IL10RA, IRF8, LY86, C1QA, C1QB, CD53, CD1C, CTSS, CCR2, CD163, CCL5, CD48, RNASE6, CD52, and CD2 were identified. In summary, through the microarray data analysis, the common functions and hub genes greatly contribute to the elucidation of the molecular pathogenesis associated with DKD.

Titanium implants and silent inflammation in jawbone-a critical interplay of dissolved titanium particles and cytokines TNF-α and RANTES/CCL5 on overall health?

BACKGROUND AND INTRODUCTION

It is a well-known fact that titanium particles deriving from dental titanium implants (DTI) dissolve into the surrounding bone. Although titanium (TI) is regarded as a compatible implant material, increasing concern is coming up that the dissolved titanium particles induce inflammatory reactions around the implant. Specifically, the inflammatory cytokine tumor necrosis factor-alpha (TNF-α) is expressed in the adjacent bone. The transition from TNF-α-induced local inflammation following insertion of DTI surgery to a chronic stage of "silent inflammation" could be a neglected cause of unexplained medical conditions.

MATERIAL AND METHODS

The signaling pathways involved in the induction of cytokine release were analyzed by multiplex analysis. We examined samples of jawbone (JB) for seven cytokines in two groups: specimens from 14 patients were analyzed in areas of DTI for particle-mediated release of cytokines. Each of the adjacent to DTI tissue samples showed clinically fatty degenerated and osteonecrotic medullary changes in the JB (FDOJ). Specimens from 19 patients were of healthy JB. In five cases, we measured the concentration of dissolved Ti particles by spectrometry.

RESULTS

All DTI-FDOJ samples showed RANTES/CCL5 (R/C) as the only extremely overexpressed cytokine. DTI-FDOJ cohort showed a 30-fold mean overexpression of R/C as compared with a control cohort of 19 healthy JB samples. Concentration of dissolved Ti particles in DTI-FDOJ was 30-fold higher than an estimated maximum of 1.000 μg/kg.

DISCUSSION

As R/C is discussed in the literature as a possible contributor to inflammatory diseases, the here-presented research examines the question of whether common DTI may provoke the development of chronic inflammation in the jawbone in an impaired state of healing. Such changes in areas of the JB may lead to hyperactivated signaling pathways of TNF-α induced R/C overexpression, and result in unrecognized sources of silent inflammation. This may contribute to disease patterns like rheumatic arthritis, multiple sclerosis, and other systemic-inflammatory diseases, which is widely discussed in scientific papers.

CONCLUSION

From a systemic perspective, we recommend that more attention be paid to the cytokine cross-talk that is provoked by dissolved Ti particles from DTI in medicine and dentistry. This may contribute to further development of personalized strategies in preventive medicine.

Pancreatic cancer therapy with combined mesothelin-redirected chimeric antigen receptor T cells and cytokine-armed oncolytic adenoviruses

Pancreatic ductal adenocarcinoma (PDA) is characterized by its highly immunosuppressive tumor microenvironment (TME) that limits T cell infiltration and induces T cell hypofunction. Mesothelin-redirected chimeric antigen receptor T cell (meso-CAR T cell) therapy has shown some efficacy in clinical trials but antitumor efficacy remains modest. We hypothesized that combined meso-CAR T cells with an oncolytic adenovirus expressing TNF-α and IL-2 (Ad5/3-E2F-D24-TNFa-IRES-IL2, or OAd-TNFa-IL2) would improve efficacy. OAd-TNFa-IL2 enhanced the antitumor efficacy of meso-CAR T cells in human-PDA-xenograft immunodeficient mice and efficacy was associated with robustly increased tumor-infiltrating lymphocytes (TILs), enhanced and prolonged T cell function. Mice treated with parental OAd combined with meso-CAR T developed tumor metastasis to the lungs even if primary tumors were controlled. However, no mice treated with combined OAd-TNFa-IL2 and meso-CAR T died of tumor metastasis. We also evaluated this approach in a syngeneic mouse tumor model by combining adenovirus expressing murine TNF-α and IL-2 (Ad-mTNFa-mIL2) and mouse CAR T cells. This approach induced significant tumor regression in mice engrafted with highly aggressive and immunosuppressive PDA tumors. Ad-mTNFa-mIL2 increased both CAR T cell and host T cell infiltration to the tumor and altered host tumor immune status with M1 polarization of macrophages and increased dendritic cell maturation. These findings indicate that combining cytokine-armed oncolytic adenovirus to enhance the efficacy of CAR T cell therapy is a promising approach to overcome the immunosuppressive TME for the treatment of PDA.

Inflammation in diabetic nephropathy: moving toward clinical biomarkers and targets for treatment

Diabetic nephropathy (DN) is a leading cause of end stage renal failure and there is an urgent need to identify new clinical biomarkers and targets for treatment to effectively prevent and slow the progression of the complication. Many lines of evidence show that inflammation is a cardinal pathogenetic mechanism in DN. Studies in animal models of experimental diabetes have demonstrated that there is a low-grade inflammation in the diabetic kidney. Both pharmacological and genetic strategies targeting inflammatory molecules have been shown to be beneficial in experimental DN. In vitro studies have cast light on the cellular mechanisms whereby diabetes triggers inflammation and in turn inflammation magnifies the kidney injury. Translation of this basic science knowledge into potential practical clinical applications is matter of great interest for researchers today. This review focuses on key pro-inflammatory systems implicated in the development of DN: the tumor necrosis factor(TNF)-α/TNF-α receptor system, the monocyte chemoattractant protein-1/CC-chemokine receptor-2 system, and the Endocannabinoid system that have been selected as they appear particularly promising for future clinical applications.

Tumor necrosis factor-α synergistically enhances polyinosinic-polycytidylic acid-induced toll-like receptor 3 signaling in cultured normal human mesangial cells: possible involvement in the pathogenesis of lupus nephritis

AIM

It has been reported that tumor necrosis factor (TNF)-α plays dual controversial roles, beneficial or detrimental, in the pathogenesis of murine lupus nephritis (LN). However, its precise role in the development of human LN remains to be determined.

METHODS

We examine the effect of pretreatment with TNF-α on the toll-like receptor 3 (TLR3) signaling induced by polyinosinic-polycytidylic acid (poly IC), a synthetic analog of viral dsRNA that makes "pseudoviral" infection in cultured normal human mesangial cells, and analyzed the expression of CC chemokine ligand 5 (CCL5) via TLR3/interferon (IFN)-β/retinoic acid-inducible gene-I (RIG-I) pathway by reverse transcriptase-polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay.

RESULTS

We found synergistic effect of TNF-α, even at low level, on the expression of CCL5 induced by poly IC in a concentration-dependent manner, in comparison with that by poly IC alone. Knockdown of either IFN-β or RIG-I decreased CCL5 expression induced by TNF-α followed by poly IC.

CONCLUSION

Pretreatment with TNF-α leads marked activation of the TLR3/IFN-β/RIG-I/CCL5 axis induced by "pseudoviral" infection. Since chronic local activation of proinflammatory cytokines including TNF-α in resident renal cells may exist in patients with active lupus, synergistic effect of TNF-α and "pseudoviral" infection is possibly involved in the development of LN.

The Fli-1 transcription factor regulates the expression of CCL5/RANTES

The friend leukemia insertion site 1 (Fli-1) transcription factor, an Ets family member, is implicated in the pathogenesis of systemic lupus erythematosus in human patients and murine models of lupus. Lupus-prone mice with reduced Fli-1 expression have significantly less nephritis, prolonged survival, and decreased infiltrating inflammatory cells into the kidney. Inflammatory chemokines, including CCL5, are critical for attracting inflammatory cells. In this study, decreased CCL5 mRNA expression was observed in kidneys of lupus-prone NZM2410 mice with reduced Fli-1 expression. CCL5 protein expression was significantly decreased in endothelial cells transfected with Fli-1-specific small interfering RNA compared with controls. Fli-1 binds to endogenous Ets binding sites in the distal region of the CCL5 promoter. Transient transfection assays demonstrate that Fli-1 drives transcription from the CCL5 promoter in a dose-dependent manner. Both Ets1, another Ets family member, and Fli-1 drive transcription from the CCL5 promoter, although Fli-1 transactivation was significantly stronger. Ets1 acts as a dominant-negative transcription factor for Fli-1, indicating that they may have at least one DNA binding site in common. Systematic deletion of DNA binding sites demonstrates the importance of the sites located within a 225-bp region of the promoter. Mutation of the Fli-1 DNA binding domain significantly reduces transactivation of the CCL5 promoter by Fli-1. We identified a novel regulator of transcription for CCL5. These results suggest that Fli-1 is a novel and critical regulator of proinflammatory chemokines and affects the pathogenesis of disease through the regulation of factors that recruit inflammatory cells to sites of inflammation.

Predictive value of conjointly examined IL-1ra, TNF-R I, TNF-R II, and RANTES in patients with primary glomerulonephritis

Interleukin-1 receptor antagonist (IL-1ra), tumor necrosis factor soluble receptors (sTNF-R) type I and II, and regulated upon activation, normal T-cell expressed and secreted (RANTES) play an important role in the modulation of primary glomerulonephritis (GN) course. The aim of the study was to assess whether pre-treatment measurements of IL-1ra, sTNF-R, and RANTES assessed conjointly may be useful as predicting factors in patients with GN. In 84 patients (45 males and 39 female) serum concentration (pg/mL) and urinary excretion (pg/mgCr) of cytokines were measured. After 12 months of therapy with steroids and cyclophosphamide the patients were divided into two subgroups: Responders (R) and Non-Responders (NR) according to the treatment results. The urinary IL-1ra, TNF-RI and RII were significantly higher in R than NR (1,732 vs 646 with P < 0.001, 13.1 vs 6.3 with P = 0.005, and 33.6 vs 14.4 with P = 0.012). The urinary RANTES excretion was increased in NR (79.6 vs 28.5; P < 0.001). The multivariable analysis showed that if conjointly assessed, only urinary IL-1ra, TNF-R I and R II, RANTES with 85% probability pointed the feature remission (R). In conclusion, the urinary excretion of IL-1ra, TNF-R I and R II, and RANTES examined conjointly are effective in predicting favorable response to immunosuppressive treatment in patients with GN.

Urinary cytokine profiles in unilateral congenital hydronephrosis

BACKGROUND

We aimed to evaluate possible clinical application of urinary monocyte chemotactic protein-1 (MCP-1), osteopontin (OPN), and regulated upon activation, normal T-cell expressed and secreted (RANTES) chemokine as useful noninvasive markers in children with congenital hydronephrosis (HN) caused by ureteropelvic junction obstruction (UPJO).

METHODS

The study cohort consisted of surgical cases (study group 1), comprising 15 children with severe HN who required surgery (median age 1.03 years), conservative cases (study group 2), comprising 21 patients with mild, nonobstructive HN, and control group, comprising 19 healthy children. All children had normal renal function. Urinary (u) concentrations of MCP-1, OPN, and RANTES were measured using immunoenzymatic enzyme-linked immunosorbent assay (ELISA) commercial kits and were expressed in nanograms per milligram creatinine. Increased levels of MCP-1 and OPN were found in children with HN in comparison with study group 2 and controls (p < 0.05). UMCP-1/Cr correlated with half-time (T(1/2)) of the elimination phase of tracer excretion of technetium-99m-mercaptoacetyltriglycine ((99m)Tc-MAG-3) (p < 0.05).

RESULTS

Receiver operator characteristic (ROC) analyses revealed good diagnostic profile for uMCP-1 only in identifying children (<40 %) with abnormal differential renal function (DRF) [area under the curve (AUC) 0.862], and in detecting kidney injury in all examined children (AUC 0.704).

CONCLUSIONS

Additional studies with larger number of patients are required to confirm a potential application of uMCP-1 as a promising parameter for early identification of kidney obstruction.

Periostin is induced in glomerular injury and expressed de novo in interstitial renal fibrosis

Matricellular proteins participate in the pathogenesis of chronic kidney diseases. We analyzed glomerular gene expression profiles from patients with proteinuric diseases to identify matricellular proteins contributing to the progression of human nephropathies. Several genes encoding matricellular proteins, such as SPARC, THBS1, and CTGF, were induced in progressive nephropathies, but not in nonprogressive minimal-change disease. Periostin showed the highest induction, and its transcript levels correlated negatively with glomerular filtration rate in both glomerular and tubulointerstitial specimen. In well-preserved renal tissue, periostin localized to the glomerular tuft, the vascular pole, and along Bowman's capsule; no signal was detected in the tubulointerstitial compartment. Biopsies from patients with glomerulopathies and renal dysfunction showed enhanced periostin expression in the mesangium, tubular interstitium, and sites of fibrosis. Periostin staining correlated negatively with renal function. α-smooth muscle actin-positive mesangial and interstitial cells localized close to periostin-positive sites, as indicated by co-immunofluorescence. In vitro stimulation of mesangial cells by external addition of TGF-β1 resulted in robust induction of periostin. Addition of periostin to mesangial cells induced cell proliferation and decreased the number of cells expressing activated caspase-3, a marker of apoptosis. These human data indicate for the first time a role of periostin in glomerular and interstitial injury in acquired nephropathies.

Loss of the receptor tyrosine kinase Axl leads to enhanced inflammation in the CNS and delayed removal of myelin debris during experimental autoimmune encephalomyelitis

Background

Axl, together with Tyro3 and Mer, constitute the TAM family of receptor tyrosine kinases. In the nervous system, Axl and its ligand Growth-arrest-specific protein 6 (Gas6) are expressed on multiple cell types. Axl functions in dampening the immune response, regulating cytokine secretion, clearing apoptotic cells and debris, and maintaining cell survival. Axl is upregulated in various disease states, such as in the cuprizone toxicity-induced model of demyelination and in multiple sclerosis (MS) lesions, suggesting that it plays a role in disease pathogenesis. To test for this, we studied the susceptibility of Axl-/- mice to experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis.

Methods

WT and Axl-/- mice were immunized with myelin oligodendrocyte glycoprotein (MOG)_35-55 peptide emulsified in complete Freund's adjuvant and injected with pertussis toxin on day 0 and day 2. Mice were monitored daily for clinical signs of disease and analyzed for pathology during the acute phase of disease. Immunological responses were monitored by flow cytometry, cytokine analysis and proliferation assays.

Results

Axl-/- mice had a significantly more severe acute phase of EAE than WT mice. Axl-/- mice had more spinal cord lesions with larger inflammatory cuffs, more demyelination, and more axonal damage than WT mice during EAE. Strikingly, lesions in Axl-/- mice had more intense Oil-Red-O staining indicative of inefficient clearance of myelin debris. Fewer activated microglia/macrophages (Iba1+) were found in and/or surrounding lesions in Axl-/- mice relative to WT mice. In contrast, no significant differences were noted in immune cell responses between naïve and sensitized animals.

Conclusions

These data show that Axl alleviates EAE disease progression and suggests that in EAE Axl functions in the recruitment of microglia/macrophages and in the clearance of debris following demyelination. In addition, these data provide further support that administration of the Axl ligand Gas6 could be therapeutic for immune-mediated demyelinating diseases.

Resequencing of the CCL5 and CCR5 genes and investigation of variants for association with diabetic nephropathy

Chemokine (C-C motif) ligand 5 (CCL5) and chemokine (C-C motif) receptor 5 are implicated in the pathogenesis of diabetic nephropathy (DN). We hypothesize that variants in these genes may be associated with DN. The CCL5 and chemokine receptor type 5 (CCR5) genes were resequenced, variants identified (n=58), allele frequencies determined in 46 individuals (92 chromosomes) and efficient haplotype tag single-nucleotide polymorphisms (htSNPs) selected to effectively evaluate the common variation in these genes. One reportedly functional gene variant and eight htSNPs were genotyped in a case-control association study involving Caucasian individuals with type 1 diabetes (267 cases with DN and 442 non-nephropathic diabetic controls). Genotyping was performed using MassARRAY iPLEX, TaqMan, gel electrophoresis and direct capillary sequencing. After correction for multiple testing, there were no statistically significant associations between variants in the CCL5 and CCR5 genes and DN.

Rho kinase inhibition attenuates LPS-induced renal failure in mice in part by attenuation of NF-kappaB p65 signaling

Rho kinase signaling regulates inflammatory cell migration and chemokine production. We therefore investigated the mechanisms of Rho-kinase-dependent inflammation in lipopolysaccharide (LPS)-induced renal failure. C57/BL6 mice received intraperitoneal LPS with or without daily treatment with specific Rho kinase inhibitors (Y-27632 or HA-1077; 5 mg/kg). Rho kinase inhibitors were applied in a preventive (12 or 1 h before LPS) or a therapeutic (6 h after LPS) scheme. Both protected renal function and decreased tubular injury in LPS-treated mice. Enhanced Rho kinase activity was inhibited by HA-1077 in capillary endothelial cells, inflammatory cells, and tubuli by analysis of Rho kinase substrate phosphorylation. Early neutrophil influx was reduced by HA-1077 without reduction of the proinflammatory cytokine TNFalpha. In contrast, HA-1077 decreased the influx of monocytes/macrophages coinciding with reduced expression of the NF-kappaB-regulated chemokines CCL5 and CCL2. We therefore examined NF-kappaB signal transduction and found that NF-kappaB p65 phosphorylation and nuclear translocation were reduced by Rho kinase inhibition. IkappaBalpha degradation was not altered during the first 6 h but was reduced by HA-1077 at later time points. NF-kappaB p50-deficient mice were similarly protected from renal injury by Rho kinase inhibition further supporting the prominent role for p65 in Rho kinase inhibition. Together, these data suggest that Rho kinase inhibition by preventive or therapeutic treatment effectively reduced endotoxic kidney injury in part by attenuation of NF-kappaB p65 activation.

Toll-like receptor 4 ligation on intrinsic renal cells contributes to the induction of antibody-mediated glomerulonephritis via CXCL1 and CXCL2

Autoimmune diseases such as glomerulonephritis are exacerbated by infection. This study examined the effect of the Toll-like receptor 4 (TLR4) ligand lipid A on the development of heterologous nephrotoxic nephritis. Administration of nephrotoxic antibody resulted in significant glomerular neutrophil infiltration and albuminuria only when a TLR4 ligand was administered simultaneously. The contribution of TLR4 on renal cells and circulating leukocytes was assessed. Bone marrow chimeras were constructed with TLR4 only on renal cells or bone marrow-derived cells. The administration of nephrotoxic serum and lipid A caused a neutrophil influx in both chimeric groups greater than in sham chimeras that were totally TLR4 deficient but significantly less than in sham chimeras that were totally TLR4 sufficient. Both chimeric groups had greater albuminuria than totally TLR4-deficient sham chimeras; however, the chimeras with TLR4 only on intrinsic renal cells had significantly less than the sham positive group. In situ hybridization showed expression of TLR4 mRNA in mesangial cells and glomerular epithelial cells. For investigation of the potential mechanism by which renal cells could contribute to disease exacerbation, mesangial cells were cultured and found to express mRNA for TLR4, and stimulation of wild-type and TLR4-deficient mesangial cells with LPS caused production of CXC chemokines by wild-type cells only. Treatment of chimeras with TLR4 present only on intrinsic renal cells with anti-CXCL1 and anti-CXCL2 antibody before disease induction significantly reduced renal neutrophil infiltration. These results show that TLR4 on both circulating leukocytes and intrinsic renal cells contributes to the inflammatory effects of antibody deposition within the glomerulus, which depends at least in part on the production of CXC chemokines by intrinsic renal cells.

Association of TGFbeta1, TNFalpha, CCR2 and CCR5 gene polymorphisms in type-2 diabetes and renal insufficiency among Asian Indians

Background

Cytokines play an important role in the development of diabetic chronic renal insufficiency (CRI). Transforming growth factor β1 (TGF β1) induces renal hypertrophy and fibrosis, and cytokines like tumor necrosis factor-alpha (TNFα), chemoattractant protein-1 (MCP-1), and regulated upon activation and normal T cell expressed and secreted (RANTES) mediate macrophage infiltration into kidney. Over expression of these chemokines leads to glomerulosclerosis and interstitial fibrosis. The effect of MCP-1 and RANTES on kidney is conferred by their receptors i.e., chemokine receptor (CCR)-2 and CCR-5 respectively. We tested association of nine single nucleotide polymorphisms (SNPs) from TGFβ1, TNFα, CCR2 and CCR5 genes among individuals with type-2 diabetes with and without renal insufficiency.

Methods

Type-2 diabetes subjects with chronic renal insufficiency (serum creatinine ≥ 3.0 mg/dl) constituted the cases, and matched individuals with diabetes of duration ≥ 10 years and normoalbuminuria were evaluated as controls from four centres in India. Allelic and genotypic contributions of nine SNPs from TGFβ1, TNFα, CCR2 and CCR5 genes to diabetic CRI were tested by computing odds ratio (OR) and 95% confidence intervals (CI). Sub-analysis of CRI cases diabetic retinopathy status as dependent variable and SNP genotypes as independent variable in a univariate logistic regression was also performed.

Results

SNPs Tyr81His and Thr263Ile in TGF β1 gene were monomorphic, and Arg25Pro in TGF β1 gene and Δ32 polymorphism in CCR5 gene were minor variants (minor allele frequency <0.05) and therefore were not considered for case-control analysis. A significant allelic association of 59029G>A SNP of CCR5 gene has been observed and the allele 59029A seems to confer predisposition to development of diabetic CRI (OR 1.39; CI 1.04–1.84). In CRI subjects a compound group of genotypes "GA and AA" of SNP G>A -800 was found to confer predisposition for proliferative retinopathy (OR 3.03; CI 1.08–8.50, p = 0.035).

Conclusion

Of the various cytokine gene polymorphisms tested, allele 59029A of CCR5 gene is significantly associated with diabetic renal insufficiency among Asian Indians. Result obtained for 59029G>A SNP of CCR5 gene is in conformity with reports from a Japanese population but due to sub-optimal power of the sample, replication in larger sample set is warranted.

TLR2 stimulation of intrinsic renal cells in the induction of immune-mediated glomerulonephritis

Infection may exacerbate organ-specific autoimmune disease such as glomerulonephritis. This may occur in the absence of a measurable effect on the adaptive immune response, and the mechanisms responsible are not fully understood. To investigate this, we have studied the effect of TLR2 ligation by the synthetic ligand Pam(3)CysSK(4) on the development of glomerulonephritis in mice. We demonstrated that glomerular inflammation induced by passive administration of nephrotoxic Ab does not occur in the absence of TLR2 stimulation, with a strong synergy when Ab deposition and TLR2 stimulation occur together. Parameters of glomerular inflammation were neutrophil influx, thrombosis, and albuminuria. To investigate the relative contribution of TLR2 on bone marrow-derived cells and intrinsic renal cells, we constructed bone marrow chimeras. Nephrotoxic Ab and TLR2 ligation caused a neutrophil influx in both types of chimera above [corrected] that seen in sham chimeras totally TLR2 deficient [corrected] Albuminuria was seen in both types of chimera above that seen in sham chimeras that were totally TLR2 deficient. This was greater in chimeras with TLR2 present on bone marrow-derived cells. To find a potential mechanism by which intrinsic renal cells may contribute toward disease exacerbation, mesangial cells were studied and shown to express TLR2 and MyD88. Wild-type but not TLR2-deficient mesangial cells produced CXC chemokines in response to stimulation with Pam(3)CysSK(4). These results demonstrate that TLR2 stimulation on both bone marrow-derived and resident tissue cells plays a role in amplifying the inflammatory effects of Ab deposition in the glomerulus.

Angiotensin II upregulates toll-like receptor 4 on mesangial cells

Angiotensin II (AngII) mediates proinflammatory properties by activating NF-kappaB transcription factor nuclear translocation and inducing the expression of chemokines. For examination of whether AngII modulates the expression of Toll-like receptor 4 (TLR4), a key element of the innate immune system that senses LPS, mouse mesangial cells (MMC) were treated with AngII. AngII upregulated TLR4 mRNA and protein in MMC, and this effect was mediated through AngII type 1 receptors. Reporter gene experiments indicate that an activating protein-1 (AP-1) as well as an E-26 specific sequence (Ets) binding site in the TLR4 promoter are responsible for the AngII-stimulated transcriptional activity of the TLR4 gene. Preincubation of MMC with AngII enhanced LPS-induced NF-kappaB activation and chemokine expression. Immunohistochemical analyses revealed that double-transgenic rats that overexpressed human renin and angiotensinogen expressed higher levels of glomerular TLR4 compared with normal Sprague-Dawley rats. In vivo, infusion with AngII but not with norepinephrine into rats for 7 d also enhanced glomerular NF-kappaB activation after systemic application of LPS, suggesting that the effects are independent of concomitantly induced hypertension. Together, these observations suggest that AngII leads to an activation of the innate immune system by a novel mechanism involving the upregulation of TLR4. Our data contribute to a better understanding of how exogenous infections may trigger renal autoimmune processes, particularly in pathophysiologic situations with high renal AngII concentrations. Because TLR4 binds endogenous ligands (e.g., extracellular matrix components) in addition to microbial products, AngII-mediated upregulation of TLR4 also could be relevant for the development of inflammation in many noninfectious renal diseases.

Signaling through up-regulated C3a receptor is key to the development of experimental lupus nephritis

Signaling of the C3a anaphylatoxin through its G protein-coupled receptor, C3aR, is relevant in a variety of inflammatory diseases, but its role in lupus nephritis is undefined. In this study, we show that expression of C3aR was significantly increased in prediseased and diseased kidneys of MRL/lpr lupus mice compared with MRL/+ controls. To investigate the role of C3aR in experimental lupus, a small molecule antagonist of C3aR (C3aRa) was administered continuously to MRL/lpr mice from 13 to 19 wk of age. All 13 C3aRa-treated mice survived during the 6-wk treatment compared with 9 of 14 (64.3%) control animals given vehicle (p = 0.019). Relative to controls, C3aRa-treated animals were protected from renal disease as measured by albuminuria (p = 0.040) and blood urea nitrogen (p = 0.021). In addition, there were fewer neutrophils, monocytes, and apoptotic cells in the kidneys of C3aRa-treated mice. C3aRa treatment also led to reduced renal IL-1beta and RANTES mRNA and phosphorylated phosphatase and tensin homologue deleted on chromosome 10 protein, whereas the mass of phosphorylated protein kinase B/Akt was increased by C3aRa. Thus, C3aR antagonism significantly reduces renal disease in MRL/lpr mice, which further translates into prolonged survival. These data illustrate that C3aR is relevant in experimental lupus nephritis and may be a target for therapeutic intervention in the human disease.

Reconstruction of renal glomerular tissue using collagen vitrigel scaffold

The construction of renal glomerular tissue has provided an important tool not only for the understanding of renal physiology and pathology in blood ultrafiltration and cell dysfunction, but also in the application of tissue engineering to glomeruli regeneration and nephritic therapy. In this study, a novel method to reconstruct glomerular tissue combining cultured cells on a collagen vitrigel scaffold is described. The method consists of two newly developed techniques, one to isolate glomerular epithelial and mesangial cells rapidly from kidney, which facilitates the prolongation of cell population doublings and allows a long-term cell culture without losing cellular features, and another to prepare a stable and thin transparent collagen gel membrane termed collagen vitrigel that can facilitate three-dimensional cultures for reconstructing an epithelial-mesenchymal model. By combining the two methods, we cocultured glomerular epithelial and mesangial cells on both surfaces of the collagen vitrigel by the manipulation of two-dimensional cultures, resulting in the successful reconstruction of a three-dimensional glomerular organoid. The coculture results showed that the collagen vitrigel maintains cell growth and cell viability for more than 1 month, and surprisingly, the epithelial layer demonstrated polarity formation, which usually appears in in vivo normal epithelial cells existing at the glomerular basement membrane, but seldom appears in epithelial cells cultured in vitro. Moreover, the coculture results showed that fibronectin, an extracellular matrix component, and integrin beta1, a receptor of fibronectin, were detected in high amounts on both cells, suggesting our collagen vitrigel can provide a suitable environment for cell-cell interactions that stabilize the cell structure and may contribute to the polarity formation of epithelial cells.

Heparan sulfate proteoglycans in glomerular inflammation

Heparan sulfate proteoglycans (HSPGs) are glycoproteins consisting of a core protein to which linear heparan sulfate side chains are covalently attached. These heparan sulfate side chains can be modified at different positions by several enzymes, which include N-deacetylases, N- and O-sulfotransferases, and an epimerase. These heparan sulfate modifications give rise to an enormous structural diversity, which corresponds to the variety of biologic functions mediated by heparan sulfate, including its role in inflammation. The HSPGs in the glomerular basement membrane (GBM), perlecan, agrin, and collagen XVIII, play an important role in the charge-selective permeability of the glomerular filter. In addition to these HSPGs, various cell types express HSPGs at their cell surface, which include syndecans, glypicans, CD44, and betaglycan. During inflammation, HSPGs, especially heparan sulfate, in the extracellular matrix (ECM) and at the surface of endothelial cells bind chemokines, which establishes a local concentration gradient recruiting leukocytes. Endothelial and leukocyte cell surface HSPGs also play a role in their direct adhesive interactions via other cell surface adhesion molecules, such as selectins and beta2 integrin. Activated leukocytes and endothelial cells exert heparanase activity, resulting in degradation of heparan sulfate moieties in the ECM, which facilitates leukocyte passage into tissues and the release of heparan sulfate-bound factors. In various renal inflammatory diseases the expression of agrin and GBM-associated heparan sulfate is decreased, while the expression of CD44 is increased. Heparan sulfate or heparin preparations affect inflammatory cell behavior and have promising therapeutic, anti-inflammatory properties by preventing leukocyte adhesion/influx and tissue damage.

RANTES promoter genotype is associated with diabetic nephropathy in type 2 diabetic subjects

OBJECTIVE

To evaluate the effect of RANTES gene promoter polymorphism and RANTES receptor (CCR5 gene) promoter polymorphism on diabetic nephropathy in Japanese type 2 diabetic subjects.

RESEARCH DESIGN AND METHODS

A total 616 Japanese subjects with type 2 diabetes were recruited. Polymorphisms of -28 C/G and -403 G/A in the RANTES gene promoter region, and of 59029 G/A in the CCR5 gene promoter region were detected by PCR-RFLP (restriction fragment length polymorphism). The association of these genotypes with nephropathy was analyzed.

RESULTS

While the RANTES -403 genotype showed no association with nephropathy, the frequency of the -28G allele was significantly higher in the DN2 group (urinary albuminuria-to-creatinine ratio [ACR] >or=300 mg/g creatinine, serum creatinine <2.0 mg/dl) than in the DN0 (ACR <30 mg/g creatinine) and DN1 (ACR >or=30 mg/g creatinine and <300 mg/g creatinine) groups. The frequency of a RANTES -28G-positive genotype (C/G or G/G) was higher in the DN2 group than in the DN0 and DN1 groups (34% vs. 25 and 20%, P = 0.0268, chi(2) = 4.905), and the frequency of a CCR5 59029 A-positive genotype (G/A or A/A) was higher in the DN1 and DN2 groups than in the DN0 group (84 and 85% vs. 76%, P = 0.0123, chi(2) = 6.269). Discriminant analysis showed that the RANTES -28G-positive genotype and CCR5 59029A-positive genotype were independently associated with nephropathy. The percentage of macroalbuminuria was twofold higher in the subjects having -28G or 59029A and threefold higher in the subjects having -28G and 59029A than in the subjects without -28G and 59029A.

CONCLUSIONS

The RANTES promoter -28G genotype and CCR5 promoter 59029A genotype may be independent risk factors for diabetic nephropathy in patients with type 2 diabetes and may have an additive effect on nephropathy.

Tumor necrosis factor-alpha stimulates fractalkine production by mesangial cells and regulates monocyte transmigration: down-regulation by cAMP

BACKGROUND

Fractalkine is a CX3C chemokine for mononuclear cells that has been implicated in the recruitment and accumulation of monocytes seen in glomerular diseases. We investigated the mechanisms by which tumor necrosis factor (TNF)-alpha stimulates mesangial cell (MC) fractalkine expression, and the effects of MC-derived fractalkine on monocyte transmigration.

METHODS

Cultured rat MCs were incubated with TNF-alpha, with or without pretreatment with pharmacologic inhibitors of protein kinases or transcriptional factors downstream to TNF-alpha. Fractalkine mRNA and protein were analyzed by Northern and Western blotting. Translocation of nuclear factor (NF)-kappaB was evaluated by immunocytochemical staining. Monocyte transmigration was determined by in vitro chemotaxis assay.

RESULTS

TNF-alpha stimulated MC fractalkine mRNA as well as cell-bound and soluble protein expression in a dose- and time-dependent manner. The soluble fractalkine was shed from the cell-bound form via metalloproteinase-dependent cleavage, and mediated in part TNF-alpha-induced monocyte transmigration in vitro. The incubation of MCs with calphostin C [a selective inhibitor of protein kinase C (PKC)] or PD98059 [a selective inhibitor of p42/44 mitogen-activated protein kinase (MAPK) kinase] attenuated TNF-alpha-stimulated fractalkine mRNA and protein expression. Coincubation of MCs with calphostin C and PD98059 resulted in a synergistic inhibition of TNF-alpha-stimulated fractalkine mRNA and protein expression. Incubation of MCs with phorbol myristate acetate (PMA) for four hours resulted in an increase in fractalkine mRNA expression that could be suppressed by calphostin C or depletion of PKC by pretreatment with PMA for 24 hours. Further, activation of PKC-depleted MCs with TNF-alpha stimulated fractalkine mRNA expression that could be blocked by calphostin C. PD 98059, but not calphostin C, inhibited TNF-alpha-activated phospho-p42/44 MAPK and phospho-c-Jun levels, whereas only calphostin C inhibited TNF-alpha-activated phosphorylation of PKCzeta/iota. The incubation of MCs with MG132, a NF-kappaB inhibitor, abolished TNF-alpha-induced degradation of inhibitory protein of NF-kappaB (I-kappaB)alpha, nuclear translocation of NF-kappaB, and fractalkine expression, without affecting phospho-c-Jun levels. In contrast, curcumin, an activating protein (AP)-1 inhibitor, attenuated TNF-alpha-stimulated phospho-c-Jun levels and fractalkine expression without discernible effects on TNF-alpha-induced degradation of I-kappaBalpha or NF-kappaB nuclear translocation. Neither PD 98059 nor calphostin C affected TNF-alpha-induced degradation of I-kappaBalpha or NF-kappaB nuclear translocation. Additional experiments examining the role of cAMP on MC fractalkine expression showed that the incubation of MCs with TNF-alpha and either db-cAMP or forskolin attenuated TNF-alpha-stimulated fractalkine mRNA and protein expression, preceded by attenuation of TNF-alpha-activated phosphorylation of p42/44 MAPK, and c-Jun, but not phosphorylation of PKCzeta/iota or nuclear translocation of NF-kappaB.

CONCLUSION

The present data indicate that TNF-alpha activation of PKCzeta/iota, p42/44 MAPK, c-Jun/AP-1, and p65/NF-kappaB are involved in TNF-alpha-stimulated MC fractalkine expression, with the soluble fractalkine mediating in part the TNF-alpha-induced monocyte transmigration in vitro. Uncoupling of p42/44 MAPK or c-Jun/AP-1 signals may contribute to cAMP inhibition of MC fractalkine expression activated by TNF-alpha.

Obstructive nephropathy and renal fibrosis

Interstitial fibrosis has a major role in the progression of renal diseases. Several animal models are available for the study of renal fibrosis. The models of aminonucleoside-induced nephrotic syndrome, cyclosporin nephrotoxicity, and passive Heyman nephritis are characterized by molecular and cellular events similar to those that occur in obstructive nephropathy. Additionally, inhibition of angiotensin-converting enzyme exerts salutary effects on the progression of renal fibrosis in obstructive nephropathy. Unilateral ureteral obstruction (UUO) has emerged as an important model for the study of the mechanisms of renal fibrosis and also for the evaluation of the impact of potential therapeutic approaches to ameliorate renal disease. Many quantifiable pathophysiological events occur over the span of 1 wk of UUO, making this an attractive model for study. This paper reviews some of the ongoing studies that utilized a rodent model of UUO. Some of the findings of the animal model have been compared with observations made in patients with obstructive nephropathy. Most of the evidence suggests that the rodent model of UUO is reflective of human renal disease processes.

IFNgamma induces functional chemokine receptor expression in human mesangial cells

Infiltration of leucocyte populations into sites of inflammation is a common feature in renal diseases. Glomerular mesangial cells are potent producers of a variety of chemokines, leading to specific attraction of distinct types of inflammatory leucocytes into the glomerulus, but so far there is limited knowledge about the responsiveness of mesangial cells to chemokines. We investigated the expression of chemokine receptors and the responsiveness of primary human mesangial cells (HMC) to the chemokines which they produce, namely monocyte chemoattractant protein-1 (MCP-1) and interleukin (IL)-8. We found that mRNAs of the chemokine receptors CCR1, which has been shown before, CCR2 and CXCR2 were induced by T-helper cytokine interferon-gamma (IFNgamma). In IFNgamma-stimulated cells, CCR2 and CXCR2 were detectable by flow cytometry. Following treatment with IFNgamma, HMC responded to MCP-1 and IL-8 with an increase of IL-6 mRNA and protein expression, which was in part blocked by pertussis toxin. Moreover, chemokine stimulation of transfected HMC led to an activation of the immunoregulatory transcription factors NFkappaB and AP-1. Additionally, we found that MCP-1 enhanced the expression of its own mRNA in cells activated to express CCR2, suggesting autocrine feedback mechanisms in MCP-1 regulation. Finally, IFNgamma-activated cells migrated towards an MCP-1 gradient in a chemotaxis assay. These results strengthen the assumption that chemokines are not only involved in the recruitment of immune cells to inflamed tissues, but also seem to play a central role in the autocrine regulation of local tissue cells, leading to proceeding inflammation and possibly contributing to healing by mediating cell growth and migration.

Role of RANTES in the development of autoimmune tissue injuries in MRL-Fas lpr mice

MRL-Fas lpr mice spontaneously develop a severe autoimmune disease closely resembling human SLE. To investigate the possible role of RANTES in autoimmune tissue injuries, we have constructed RANTES-deficient MRL-Fas lpr mice by gene targeting. In the RANTES-deficient mice, axillary lymph nodes were significantly reduced in size compared with those of RANTES-intact mice. Flow cytometric analysis revealed that double-negative (DN) T cells were significantly reduced. Image analyzer showed that cell-infiltrated areas in peribronchial lesions were decreased in the lung of RANTES-deficient MRL-Fas lpr mice. Furthermore, we detected continuous expression of RANTES mRNA in the lung of MRL-Fas lpr mice. In contrast, the degree of histological renal injuries and survival rate was similar in both genotypes. We speculate that RANTES is involved in the development of peribronchial pulmonary lesions in MRL-Fas lpr mice. Further studies using RANTES-deficient mice might contribute to the elucidation of the role of RANTES in autoimmune tissue injuries.

Impaired T cell function in RANTES-deficient mice

The chemokine RANTES is a chemoattractant for monocytes and T cells and is postulated to participate in many aspects of the immune response. To evaluate the biological roles of RANTES in vivo, we generated RANTES-deficient (-/-) mice and characterized their T cell function. In cutaneous delayed-type hypersensitivity assays, a 50% reduction in ear and footpad swelling was seen in -/- mice compared to +/+ mice. In vitro, polyclonal and antigen-specific T cell proliferation was decreased. Quantitative analysis using the fluorescent dye carboxy-fluorescein succinimidyl ester revealed that this proliferative defect was due both to fewer antigen-reactive T cells and to a reduction in the capacity of these cells to proliferate. In addition, IFN-gamma and IL-2 production by the -/- T cells was dramatically decreased. Together, these data suggest that RANTES is required for normal T cell functions as well as for recruiting monocytes and T cells to sites of inflammation.

Chemokine receptor genotype is associated with diabetic nephropathy in Japanese with type 2 diabetes

Glomerular infiltration of monocytes/macrophages occurs in diabetic patients with nephropathy, and chemokine receptor signals are thought to play a key role in the development of nephropathy. Recently, polymorphism of the chemokine receptor (CCR)2 coding region V64I and the CCR5 promoter region 59029 (G/A) have been identified. Accordingly, we evaluated the effects of these genotypes on diabetic nephropathy. CCR2 V64I and CCR5 59029 (G/A) were detected by polymerase chain reaction-restriction fragment-length polymorphism in 401 patients with type 2 diabetes who had a serum creatinine <2.0 mg/dl. Although the CCR2 V64I genotype showed no association with nephropathy, the frequency of the CCR5 59029 A-positive genotype (G/A or A/A) was significantly higher in patients with microalbuminuria (urinary albumin-to-creatinine ratio [ACR] > or = 30 and <300 mg/gCre, 86%) and patients with macroalbuminuria (ACR > or = 300 mg/gCre, 87%) than in patients with normoalbuminuria (ACR <30 mg/gCre, 75%; P = 0.0095). Polytomic logistic regression analysis showed that the CCR5 59029 A-positive genotype was associated with nephropathy (odds ratio 2.243, P = 0.0074). These results suggest that the CCR5 promoter 59029 A genotype may be an independent risk factor for diabetic nephropathy in patients with type 2 diabetes.

Combinatorial model of chemokine involvement in glomerular monocyte recruitment: role of CXC chemokine receptor 2 in infiltration during nephrotoxic nephritis

A sequential model involving chemokines has been proposed for leukocyte extravasation into areas of inflammation; however, site-specific aspects remain to be elucidated. Hence, we studied the role of chemokines produced by mesangial (MC) or glomerular endothelial cells (GEC) and their receptors in glomerular recruitment of monocytes. Stimulation of MC with TNF-alpha up-regulated mRNA and protein of CC and CXC chemokines but not constitutive expression of the CX(3)C chemokine fractalkine. While growth-related activity (GRO)-alpha was immobilized to MC proteoglycans, monocyte chemotactic protein (MCP)-1 was secreted into the soluble phase. Firm adhesion and sequestration of monocytes on activated MC was supported by the GRO-alpha receptor CXCR2 and to a lesser extent by CX(3)CR, whereas the MCP-1 receptor CCR2 contributed to their transendothelial chemotaxis toward activated MC. In contrast, fractalkine mRNA and protein was induced by TNF-alpha in transformed rat GEC, and both CXCR2 and CX(3)CR mediated monocyte arrest on GEC in shear flow. The relevance of these mechanisms was confirmed in a rat nephrotoxic nephritis model where acute glomerular macrophage recruitment was profoundly inhibited by blocking CXCR2 or CCR2. In conclusion, our results epitomize a combinatorial model in which chemokines play specialized roles in driving glomerular monocyte recruitment and emphasize an important role for CXCR2 in macrophage infiltration during early phases of nephrotoxic nephritis.

Lupus nephritis: lessons from experimental animal models

Lupus nephritis is a frequent and severe complication of SLE. In the last decades, animal models for SLE have been studied widely to investigate the immunopathology of this autoimmune disease because abnormalities can be studied and manipulated before clinical signs of the disease become apparent. In this review an overview is given of our current knowledge on the development of lupus nephritis, as derived from animal models, and a hypothetical pathway for the development of lupus nephritis is postulated. The relevance of the studies in experimental models in relationship with our knowledge of human SLE is discussed.

Receptor mediated endocytosis by mesangial cells modulates transmigration of macrophages

BACKGROUND

Accumulation of immune complexes in the mesangium is a common finding. Since migration of macrophages (Mphi) in the mesangium has been demonstrated to be an important event in the development of glomerular lesions, we studied the role of immune complexes and mesangial cell (MC) interaction in the transmigration (Tm) of Mphi.

METHODS

To determine the effect of MC and immune complexes (aggregated IgG, IgGAg) on transmigration of Mphi. MC were incubated with or without IgGAg in the lower compartment of a modified Boyden Chamber. To determine the effects of the secretory products (as a result of endocytosis of IgGAg by mesangial cells), MC-IgAg conditioned media was prepared and placed in the lower compartment of the Boyden chamber. We evaluated the effects of MC alone, MC + IgGAg, or MC-IgGAg conditioned media on the transmigration of macrophages across a filter. To determine the effect of free radicals on MC-IgAg endocytosis-induced Mphi migration we evaluated the effect of free radical scavengers such as dimethyl thiourea (DMTU) and tetramethylthiourea (TMTU) in MC-IgAg endocytosis-induced Mphi migration. To determine the role of chemokines in MC-IgAs endocytosis-induced Mphi migration we evaluated the effect of ani-MCP-1 antibodies on MC-IgAg endocytosis-induced Mphi migration, and also studied the effects of IgAg on MC mRNA expression of MCP-1 and RANTES. In addition, we evaluated the role of Fc receptors and actin cytoskeleton of MC in transmigration of Mphi.

RESULTS

Mesangial cell endocytosis of IgG aggregates (IgGAg) is associated with enhanced (P < 0.001) transmigration of Mphi (control, 11.2 +/- 0.2 vs. MC + IgGAg, 22.1 +/- 0.9 migrated Mphi/field). IgGAg also induced MC mRNA expression for RANTES and MCP-1 on MC. DMTU and TMTU attenuated (P < 0.001) the MC + IgGAg-induced migration of Mphi as well as IgGAg-induced mRNA expression for RANTES and MCP-1. MC and IgGAg interaction products (MC-IgGAg conditioned media) also increased (P < 0.01) transmigration of Mphi (control, 18.3 +/- 1.7 vs. MC-IgGAg conditioned media, 30.7 +/- 0.6 Mphi/field). This effect of MC-IgGAg conditioned media on the migration of macrophages was dose dependent. Anti-MCP-1 antibody partially inhibited MC-IgGAg-induced migration of macrophages. MC and monomeric IgG (MIgG) interaction (MC-MIgG conditioned media) showed a lower (P < 0.05) migration of Mphi, when compared to the MC-IgGAg conditioned media. MC-IgGAg conditioned media prepared from cytochalasin B pretreated MCs also showed a lower (P < 0.001) migration of Mphi when compared with MC-IgGAg conditioned media-induced migration.

CONCLUSIONS

These results indicate that MC-IgGAg conditioned media-induced transmigration of macrophages may be mediated through the generation of RANTES and MCP-1 by MC.

Role of RANTES in experimental cardiac allograft rejection

The host response to alloantigen results in upregulation of Class II MHC antigens and associated cytokine production (especially IL-2 and interferon-gamma (IFN-gamma)) as well as lymphocytic infiltration and cellular activation which leads to graft damage/destruction. RANTES (Regulated upon Activation, Normal T-cell Expressed and presumably Secreted) is a member of the beta subfamily (CC) of chemokines and has been shown to function as a lymphocyte chemoattractant. We now describe the requirement for RANTES in cardiac heterotopic allograft (brown Norway into Lewis rats) rejection in rats. By Northern blot analysis, mRNA could be detected in allografts at 6 and 8 days post-transplantation but not in isogenic (Lewis) grafts. RANTES protein could be demonstrated by Western blot analysis in homogenates from allografts at day 8 but not at day 0 and could not be identified in isogenic cardiac transplants. By immunostaining, RANTES protein was present in mononuclear cells of allografts at day 6 but was absent in the isogenic transplants. When rats were treated with anti-RANTES serum, there was a significant delay in rejection time (cessation of beating) of the allografts. These data demonstrate that expression of RANTES in rat cardiac allografts is linked to the rejection phenomenon.

Interleukin-1beta induction of the chemokine RANTES promoter in the human astrocytoma line CH235 requires both constitutive and inducible transcription factors

The chemokine RANTES is an important mediator of inflammatory processes. In this report, we describe the DNA sequence and transcription factor requirements for interleukin-1beta (IL-1beta) induction of the RANTES promoter in the human astrocytoma line CH235. RANTES promoter sequences between -278 and +55 are sufficient for IL-1beta-inducibility. In vitro DNA binding assays demonstrate constitutive binding of Sp1, HMG, Ets domain, and bZIP family members to their cognate sites in the RANTES promoter, whereas NF-kappaB and IRF-1 bind in an IL-1beta-inducible manner. IL-1beta-inducibility of the RANTES promoter requires both constitutive and inducible transcription factors. The formation of a higher order nucleoprotein complex, or 'enhanceosome', may be critical for IL-1beta induction of the RANTES promoter.

Chemokines, chemokine receptors, and renal disease: from basic science to pathophysiologic and therapeutic studies

Leukocyte trafficking from peripheral blood into affected tissues is an essential component of the inflammatory reaction to virtually all forms of injury and is an important factor in the development of many kidney diseases. Advances in the past few years have highlighted the central role of a family of chemotactic cytokines called chemokines in this process. Chemokines help to control the selective migration and activation of inflammatory cells into injured renal tissue. Chemokines and their receptors are expressed by intrinsic renal cells as well as by infiltrating cells during renal inflammation. This study summarizes the in vitro and in vivo data on chemokines and chemokine receptors in renal diseases with a special focus on potential therapeutic effects on inflammatory processes.

Chemokine and chemokine receptor expression in a novel human mesangial cell line

Chemokines are thought to play a pivotal role in mediating the selective migration of leukocytes into sites of tissue injury. The local production of chemokines by mesangial cells (MC) has been linked to inflammatory processes within the glomerulus. To study the chemokine biology of human MC, an immortalized human MC line was generated and then chemokine and chemokine receptor expression was examined in response to various proinflammatory stimuli. The results show that human MC have a specific and limited repertoire of chemokine expression. The stimulus-specific regulation of the chemokines monocyte chemoattractant protein- (MCP- 1), regulated upon activation, normal T cell expressed and secreted (RANTES), interleukin-8 (IL-8), and IP-10 was demonstrated using RNase protection assays. Transcripts for the chemokines MIP-1alpha, MIP-1beta, I-309, or lymphotactin could not be detected. The expression of CC chemokine receptors was investigated by reverse transcription-PCR and RNase protection assays. MC stimulated with interferon-gamma (IFN-gamma) expressed mRNA for the chemokine receptor CCR1. The expression could be further increased by activating the cells with a combination of tumor necrosis factor-a (TNF-alpha), IL-1beta, and IFN-gamma. Under these conditions, no mRNA for CCR2, CCR3, CCR4, CCR5, or CCR8 was detected. A comparison of the immortalized human mesangial cells with primary cells showed identical expression patterns of chemokine receptors. To demonstrate functional activity of chemokine receptors expressed by human MC, chemotaxis assays were performed. MC stimulated with a combination of TNF-alpha, IL-1beta, and IFN-gamma, but not unstimulated MC, migrated toward a RANTES gradient. Eotaxin did not enhance the migratory activity of human MC. In summary, a novel human mesangial cell line was established and the pattern of chemokine expression was examined. For the first time, the inducible expression of functionally active CCR1 by human MC was shown.

A role for the novel cytokine RANTES in pregnancy and parturition

OBJECTIVE

RANTES (regulated on activation, normal T cell expressed and secreted), a potent and versatile chemokine, is capable of attracting monocytes, lymphocytes, basophils, and eosinophils. This cytokine has been implicated in the regulation of the inflammatory response and in the recruitment of macrophages to the implantation site in early pregnancy. RANTES messenger ribonucleic acid and protein have been detected in fetal tissue and first-trimester trophoblast in response to bacterial endotoxin. The purpose of this study was to determine whether intrauterine infection, parturition (preterm and term), and gestational age affect the amniotic fluid concentrations of RANTES in human pregnancy.

STUDY DESIGN

A cross-sectional study was designed to examine the relationship between labor, microbial invasion of the amniotic cavity, gestational age, and RANTES expression in amniotic fluid. Amniotic fluid was obtained from 214 women in the following groups: (1) midtrimester (n = 22), (2) preterm labor with intact membranes in the presence (n = 20) or absence (n = 74) of microbial invasion of the amniotic cavity, (3) term, not in labor (n = 44) and term, in labor in the presence (n = 27) and absence (n = 27) of microbial invasion of the amniotic cavity. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture for microorganisms. RANTES concentrations were determined by use of a sensitive and specific immunoassay.

RESULTS

(1) Amniotic fluid RANTES concentrations decrease with advancing gestational age (r = 0. 43; P <.01). (2) Labor at term was associated with an increase in median concentrations of RANTES (labor-median, 8.4 pg/mL; range, <1.3-94.4 vs no labor-median, <1.3 pg/mL; range, <1.3-230.3; P <.01). (3) Women with preterm labor who delivered preterm (no microbial invasion of the amniotic cavity) had a higher median concentration of amniotic fluid RANTES than those who delivered at term (median, 12.7 pg/mL; range, <1.3-928 vs median, <1.3 pg/mL; range, <1.3-127. 5; P <.001). (4) Microbial invasion of the amniotic cavity was associated with a significant increase in median amniotic fluid RANTES in both preterm and term labor (preterm labor with microbial invasion of the amniotic cavity-median, 51.6 pg/mL; range, <1.3-2290 vs preterm labor without microbial invasion of the amniotic cavity-median, 12.7 pg/mL; range, <1.3-928 and vs preterm labor with delivery at term-median, <1.3 pg/mL; range, <1.3-127.5; P <.001 for each; term labor with microbial invasion of the amniotic cavity-median, 16.8 pg/mL; range, <1.3-171.4 vs term labor without microbial invasion of the amniotic cavity-median, 8.4 pg/mL; range, <1.3-94.4; P <.05 and vs no labor and no microbial invasion of the amniotic cavity-median, 1.4 pg/mL; range, <1.3-230.3; P <.001 and P <.05, respectively).

CONCLUSION

These results support a role for RANTES in the mechanisms of human parturition and in the regulation of the host response to intrauterine infection.

Lymphotoxin α3 Induces Chemokines and Adhesion Molecules: Insight into the Role of LTα in Inflammation and Lymphoid Organ Development

Lymphotoxin (LT) plays an important role in inflammation and lymphoid organ development, though the mechanisms by which it promotes these processes are poorly understood. Toward this end, the biologic activities of a recently generated recombinant murine (m) LTα preparation were evaluated. This cytokine preparation was effective at inducing cytotoxicity of WEHI target cells with 50% maximal killing observed with 1.2 ng/ml. mLTα also induced the expression of inflammatory mediators in the murine endothelial cell line bEnd.3. rmLTα induced expression of the adhesion molecules VCAM, ICAM, E-selectin, and the mucosal addressin cellular adhesion molecule, MAdCAM-1. When mLTα, human (h) LTα, and mTNF-α were compared, mLTα was the most potent inducer of MAdCAM-1. None of these cytokines induced the peripheral node addressin, PNAd. mLTα also induced expression of the chemokines RANTES, IFN-inducible protein 10 (IP-10), and monocyte chemotactic protein 1 (MCP-1). mRNA levels peaked 4 h following treatment with mLTα and declined through the 24-h treatment period. LTα also induced chemokine protein within 8 h of treatment, which increased through the 24-h treatment period. These data demonstrate that the proinflammatory effects of LTα3 may be mediated in part through the induction of adhesion molecule and chemokine expression. Further, LTα3 may promote development of lymphoid tissue through induction of chemokines and the mucosal addressin MAdCAM-1. These data confirm previous observations in transgenic and knockout mice that LTα3 in the absence of LTβ carries out unique biologic activities.

Protein overload stimulates RANTES production by proximal tubular cells depending on NF-kappa B activation

Abnormal traffic of proteins through the glomerular capillary has an intrinsic renal toxicity possibly linked to the subsequent process of proximal tubular reabsorption. Here we investigated in vitro the effect of protein overload on proximal tubular cell production of RANTES, a nuclear factor-kappa B (NF-kappa B)-dependent chemokine with potent chemotactic activity for monocytes/macrophages and T lymphocytes. Confluent pig LLC-PK1 cells were incubated for 24 and 48 hours with Eagle's MEM plus 0.5% FCS containing bovine serum albumin (BSA, 1 to 30 mg/ml). Tumor necrosis factor-alpha (TNF-alpha; 100 U/ml) was used as a positive control. RANTES was measured in cell supernatants by ELISA. Bovine serum albumin (BSA) induced a time- and dose-dependent increase in proximal tubular cell RANTES production. Selected experiments using transwells showed that the RANTES release was predominantly basolateral. The stimulatory effect on tubular RANTES was not specific to albumin but was shared by immunoglobulin (Ig) G. We then explored the role of NF-kappa B on BSA-induced RANTES. The NF-kappa B inhibitors pyrrolidine dithiocarbamate (PDTC; 25 microM) and sodium salicylate (10 mM) significantly reduced BSA-induced RANTES production. Electrophoretic mobility shift assay of nuclear extracts of LLC-PK1 exposed to BSA revealed an intense NF-kappa B activation as early as 30 minutes in a dose-dependent fashion, which was inhibited by PDTC. Supershift analysis revealed that the protein subunits of activated NF-kappa B were p65/p65 homodimer, p65/cRel, p50/p65 heterodimers. Given its chemotactic activity, RANTES released into the interstitium might promote inflammatory cell recruitment and contribute to interstitial inflammation and renal disease progression.

Gene transfer of RANTES elicits autoimmune renal injury in MRL-Fas(1pr) mice

We report that the beta-chemokine RANTES, a chemoattractant for macrophages and T cells, is up-regulated in the MRL-Fas(1pr) kidney prior to injury, but not normal kidneys (MRL-++, C3H-++) and increases with progressive injury. Furthermore, we establish an association between RANTES expression in the kidney and renal damage using a gene transfer approach. Tubular epithelial cells genetically modified to secrete RANTES infused under the renal capsule incites interstitial nephritis in MRL-Fas(1pr), but not MRL-++ or C3H-++ mice. RANTES recruits predominantly macrophages (M phi) and CD4+ and CD8+ T cells. In contrast, gene transfer of CSF-1, another molecule up-regulated simultaneously with RANTES in MRL-Fas(1pr) kidneys, promotes the influx of M phi, CD4+ T cells and the unique double-negative (DN) T cells (CD4-, CD8-), which are prominent in diseased MRL-Fas(1pr) kidneys. Thus, RANTES and CSF-1 recruit distinct T cell populations into the MRL-Fas(1pr) kidney. In addition, delivery of RANTES and CSF-1 into the kidney of MRL-Fas(1pr) mice causes an additive increase in pathology. We suggest that the complementary recruitment of T cell populations by RANTES (CD4, CD8) and CSF-1 (CD4, DN) promotes autoimmune nephritis in MRL-Fas(1pr) mice.

Lymphocyte-derived cytokines induce sequential expression of monocyte- and T cell-specific chemokines in human mesangial cells

Chemokines are a family of small related proteins that play an important role in the selective recruitment of different leukocyte populations to the sites of inflammation. Human glomerular mesangial cells are potent producers of a variety of chemokines. Here we examined the kinetics of mesangial cell chemokine expression with focus on the C-C or beta chemokines monocyte chemoattractant protein-1 (MCP-1), regulated upon activation, normal T cell expressed and secreted (RANTES), macrophage inflammatory protein-1 alpha (MIP-1 alpha), and the C-X-C or alpha chemokine interleukin-8 (IL-8) in response to lymphocyte- or monocyte-derived cytokines and mesangial cell growth factors. It was found that interferon-gamma (IFN-gamma), a cytokine produced by TH1 lymphocytes, synergized with tumor necrosis factor-alpha (TNF-alpha) in RANTES expression and with IL-1 beta in MCP-1 synthesis. Time course studies revealed an early peak of mRNA expression of monocyte-specific MCP-1 upon activation with TNF-alpha in contrast to T cell-specific RANTES, which reached the highest mRNA level after 18 hours. This sequence of TNF-alpha-induced MCP-1 and RANTES expression was confirmed on the protein level. As another T-lymphocyte specific chemokine, MIP-1 alpha mRNA and protein was expressed only in response to TNF-alpha plus IFN-gamma with kinetics similar to those of RANTES expression. Finally, unlike other mesangial growth factors basic fibroblast growth factor (bFGF) induced MCP-1, RANTES, and IL-8 mRNA expression, suggesting an involvement of autocrine regulation mechanisms in mesangial chemokine expression.

Angiotensin II stimulates expression of the chemokine RANTES in rat glomerular endothelial cells. Role of the angiotensin type 2 receptor

Glomerular influx of monocytes/macrophages (M/M) occurs in many immune- and non-immune-mediated renal diseases. The mechanisms targeting M/M into the glomerulus are incompletely understood, but may involve stimulated expression of chemokines. We investigated whether angiotensin II (ANG II) induces the chemokine RANTES in cultured glomerular endothelial cells of the rat and in vivo. ANG II stimulated mRNA and protein expression of RANTES in cultured glomerular endothelial cells. The ANG II-induced RANTES protein was chemotactic for human monocytes. Surprisingly, the ANG II-stimulated RANTES expression was transduced by AT2 receptors because the AT2 receptor antagonists PD 123177 and CGP-42112A, but not an AT1 receptor blocker, abolished the induced RANTES synthesis. Intraperitoneal infusion of ANG II (500 ng/h) into naive rats for 4 d significantly stimulated glomerular RANTES mRNA and protein expression compared with solvent-infused controls. Immunohistochemistry revealed induction of RANTES protein mainly in glomerular endothelial cells and small capillaries. Moreover, ANG II- infused animals exhibited an increase in glomerular ED-1- positive cells compared with controls. Oral treatment with PD 123177 (50 mg/liter drinking water) attenuated the glomerular M/M influx without normalizing the slightly elevated systolic blood pressure caused by ANG II infusion, suggesting that the effects on blood pressure and RANTES induction can be separated. We conclude that the vasoactive peptide ANG II may play an important role in glomerular chemotaxis of M/M through local induction of the chemokine RANTES. The observation that the ANG II- mediated induction of RANTES is transduced by AT2 receptors may influence the decision as to which substances might be used for the therapeutic interference with the activity of the renin-angiotensin system.

Massive infiltration of basophilic cells in inflamed tissue after injection of RANTES

Regulated upon activation normal T expressed and secreted (RANTES) is a new inducible protein member of the human C-C branch of chemokines. RANTES is a potent monocyte and lymphocyte chemoattractant and is a mediator of inflammatory responses. In these studies we found that RANTES 10 ng/50 microl chemoattracts basophilic cells in a dose-dependent manner 4 h after an intradermal injection in rat skin sites, as revealed by optic microscopy. Moreover, in biopsy specimens from rat skin injection sites histamine release was significantly higher (P < 0.05) than in controls (PBS 50 microl) after 4 h from RANTES treatment. The presence of basophilic cells in rat skin injection sites after RANTES-treatment was also confirmed by electron microscopy studies. In addition, histidine decarboxylase (HDC) mRNA was increased in rat skin sites injected with RANTES compared to sites injected with PBS (controls). Our report describes additional biological activities for RANTES, suggesting that this human chemoattractant protein may play a fundamental role in histamine and HDC generation, along with basophilic cell recruitment.

RANTES and monocyte chemoattractant protein-1 (MCP-1) play an important role in the inflammatory phase of crescentic nephritis, but only MCP-1 is involved in crescent formation and interstitial fibrosis

The involvement of chemokines in inflammation is well established, but their functional role in disease progression, and particularly in the development of fibrosis, is not yet understood. To investigate the functional role that the chemokines monocyte chemoattractant protein-1 (MCP-1) and RANTES play in inflammation and the progression to fibrosis during crescentic nephritis we have developed and characterized a murine model for this syndrome. Significant increases in T-lymphocytes and macrophages were observed within glomeruli and interstitium, paralleled by an induction of mRNA expression of MCP-1 and RANTES, early after disease initiation. Blocking the function of MCP-1 or RANTES resulted in significant decreases in proteinuria as well as in numbers of infiltrating leukocytes, indicating that both MCP-1 and RANTES (regulated upon activation in normal T cells expressed and secreted) play an important role in the inflammatory phase of crescentic nephritis. In addition, neutralization of MCP-1 resulted in a dramatic decrease in both glomerular crescent formation and deposition of type I collagen. These results highlight a novel role for MCP-1 in crescent formation and development of interstitial fibrosis, and indicate that in addition to recruiting inflammatory cells this chemokine is critically involved in irreversible tissue damage.

Role of T cells in the mediation of Heymann nephritis. ii. Identification of Th1 and cytotoxic cells in glomeruli

The role of immunoglobulin (Ig) and complement as mediators of Heymann nephritis (HN) has been questioned by recent studies showing that HN can be induced in a C6-deficient rat that cannot assemble the membrane attack complex of complement. Also, the severity of HN can be reduced by therapy directed at CD8+ T cells, which has no effect on antibody (Ab) production or immune deposits. To identify whether T cells may contribute to the glomerular injury of active HN in Lewis rats, the mononuclear infiltrate and cytokine mRNA in glomeruli and kidney interstitium were examined. Groups of Lewis rats immunized with Fx1A in CFA developed HN, and were compared to controls that received CFA only. Proteinuria, the marker of glomerular filtration barrier dysfunction, was absent at four weeks but present at eight weeks in HN. Serum anti-Fx1A Ab and glomerular Ig were present in HN at both time points. Immunoperoxidase staining with monoclonal Abs identified, at eight weeks, a glomerular infiltrate of CD4+ and CD8+ T cells, and macrophages, but not NK cells. Semiquantitative RT-PCR of isolated glomeruli at eight weeks demonstrated expression of cytokine mRNA for Th1 CD4+ cells (IFN-gamma and TNF-beta/LT, but not IL-2), cytotoxic CD8+ T cells (granzyme A and perforin), and macrophages (TNF-alpha and IL-10), but not Th2 CD4+ cells (no increase in IL-4, IL-5 and IL-6). At eight weeks, the cellular infiltrate and pattern of cellular activation in glomeruli was different to that in renal cortex. In the cortical infiltrate CD8+ cells were a lesser component, and NK cells were increased, as were CD4+ cells and macrophages. RT-PCR identified increased cytokine mRNA for macrophages, Th1 and Th2 cells, but not cytotoxic effector T cells. At four weeks, T cells including CD4+ and CD8+ cells were identified in the isolated glomeruli of rats with HN, but there was no increase in cytokine mRNA expression. There was no infiltrate or increase in cytokine mRNA detected in renal cortex at four weeks. Anti-Fx1A Ab's and glomerular deposition of Ig develop many weeks before the onset of proteinuria, when there is only a small cellular infiltrate present. The progressive development of infiltrates of activated T cells, principally Th1 and cytotoxic effector cells, and macrophages, within glomeruli is coincident with the development of proteinuria. These findings raise the possibility that these cells contribute to the mediation of the glomerular injury and proteinuria of HN.

Monocyte chemoattractant protein-1 mediates monocyte/macrophage influx in anti-thymocyte antibody-induced glomerulonephritis

Chemokines are a family of chemotactic cytokines whose participation in inflammation in vivo remains to be established. To study the role of monocyte-chemoattractant-protein-1 (MCP-1) on the glomerular accumulation of leukocytes, rats received a neutralizing anti-MCP-1 antiserum following the induction of an glomerulonephritis by an anti-thymocyte antibody (ATS). The infiltration of monocytes/macrophages (M/M) and granulocytes was analyzed by immunohistology. When studied by Northern blotting, glomerular mRNA levels of MCP-1, and interleukin 1 beta (IL-1 beta) increased at three hours and 24 hours following the induction of the injury. The glomerular mRNA expression of intercellular adhesion molecule-1 (ICAM-1) only increased marginally, whereas the expression of the chemokine RANTES was not enhanced. In animals that received anti-MCP-1 antibody glomerular MCP-1 mRNA expression increased. However, the chemoattractant activity for monocytes released into supernatants of isolated glomeruli was reduced. The anti-MCP-1 antibody did not affect glomerular IL-1 beta, ICAM-1 or RANTES mRNA levels. The induction of glomerulonephritis was associated with an increased glomerular recruitment of polymorphonuclear granulocytes (PMNs) at three hours and M/M at 24 hours, when compared with controls. The anti-MCP-1 antiserum significantly reduced the glomerular M/M infiltration at 24 hours by 40%, but was without effect on glomerular PMN recruitment or growth of the resident glomerular cells. These studies demonstrate that MCP-1 is an important mediator for monocyte recruitment in this model of glomerulonephritis. The reduction of M/M infiltration might affect this glomerular injury.