Isolation and characterization of cDNA from renal tubular epithelium encoding murine Rantes

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.

Anti-Inflammatory CDGSH Iron-Sulfur Domain 2: A Biomarker of Central Nervous System Insult in Cellular, Animal Models and Patients

Spinal cord injury (SCI) promotes brain inflammation; conversely, brain injury promotes spinal neuron loss. There is a need to identify molecular biomarkers and therapeutic targets for central nervous system (CNS) injury. CDGSH iron-sulfur structural domain 2 (CISD2), an NF-κB antagonist, is downregulated after injury in vivo and in vitro. We aimed to examine the diagnostic value of CISD2 in patients with CNS insult. Plasma and cerebrospinal fluid (CSF) CISD2 levels were decreased in 13 patients with CNS insult and were negatively correlated with plasma IL6 levels (associated with disease severity; r = −0.7062; p < 0.01). SCI-induced inflammatory mediators delivered through CSF promoted mouse brain inflammation at 1 h post-SCI. Anti-CISD2 antibody treatment exacerbated SCI-induced inflammation in mouse spine and brain. Lipopolysaccharide-stimulated siCISD2-transfected EOC microglial cells exhibited proinflammatory phenotypes (enhanced M1 polarization, decreased M2 polarization, and increased intranuclear NF-κB p65 translocation). Plasma and CSF CISD2 levels were increased in three patients with CNS insult post-therapeutic hypothermia. CISD2 levels were negatively correlated with plasma and CSF levels of inflammatory mediators. CISD2 inhibition and potentiation experiments in cells, animals, and humans revealed CISD2 as a biomarker for CNS insult and upregulation of CISD2 anti-inflammatory properties as a potential therapeutic strategy for CNS insult.

NF-κB is required for dengue virus NS5-induced RANTES expression

Dengue virus (DENV) infection associates with renal disorders. Patients with dengue hemorrhagic fever and acute kidney injury have a high mortality rate. Increased levels of cytokines may contribute to the pathogenesis of DENV-induced kidney injury. Currently, molecular mechanisms how DENV induces kidney cell injury has not been thoroughly investigated. Excessive cytokine production may be involved in this process. Using human cytokine RT(2) Profiler PCR array, 14 genes including IP-10, RANTES, IL-8, CXCL-9 and MIP-1β were up-regulated more than 2 folds in DENV-infected HEK 293 cells compared to that of mock-infected HEK 293 cells. In the present study, RANTES was suppressed by the NF-κB inhibitor, compound A (CpdA), in DENV-infected HEK 293 cells implying the role of NF-κB in RANTES expression. Chromatin immunoprecipitation (ChIP) assay showed that NF-κB binds more efficiently to its binding sites on the RANTES promoter in NS5-transfected HEK 293 cells than in HEK 293 cells expressing the vector lacking NS5 gene. To further examine whether the NS5-activated RANTES promoter is mediated through NF-κB, the two NF-κB binding sites on the RANTES promoter were mutated and this promoter was coupled to the luciferase cDNA. The result showed that when both binding sites of NF-κB in the RANTES promoter were mutated, the ability of NS5 to induce the luciferase activity was significantly decreased. Therefore, DENV NS5 activates RANTES production by increasing NF-κB binding to its binding sites on the RANTES promoter.

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.

Crosstalk between medulloblastoma cells and endothelium triggers a strong chemotactic signal recruiting T lymphocytes to the tumor microenvironment

Cancer cells can live and grow if they succeed in creating a favorable niche that often includes elements from the immune system. While T lymphocytes play an important role in the host response to tumor growth, the mechanism of their trafficking to the tumor remains poorly understood. We show here that T lymphocytes consistently infiltrate the primary brain cancer, medulloblastoma. We demonstrate, both in vitro and in vivo, that these T lymphocytes are attracted to tumor deposits only after the tumor cells have interacted with tumor vascular endothelium. Macrophage Migration Inhibitory Factor (MIF)" is the key chemokine molecule secreted by tumor cells which induces the tumor vascular endothelial cells to secrete the potent T lymphocyte attractant "Regulated upon Activation, Normal T-cell Expressed, and Secreted (RANTES)." This in turn creates a chemotactic gradient for RANTES-receptor bearing T lymphocytes. Manipulation of this pathway could have important therapeutic implications.

Synergy in cytokine and chemokine networks amplifies the inflammatory response

The inflammatory response is a highly co-ordinated process involving multiple factors acting in a complex network as stimulators or inhibitors. Upon infection, the sequential release of exogenous agents (e.g. bacterial and viral products) and induction of endogenous mediators (e.g. cytokines and chemokines) contribute to the recruitment of circulating leukocytes to the inflamed tissue. Microbial products trigger multiple cell types to release cytokines, which in turn are potent inducers of chemokines. Primary cytokines act as endogenous activators of the immune response, whereas inducible chemokines act as secondary mediators to attract leukocytes. Interaction between exogenous and endogenous mediators thus enhances the inflammatory response. In this review, the synergistic interaction between cytokines to induce chemokine production and the molecular mechanisms of the cooperation amongst co-induced chemokines to further increase leukocyte recruitment to the site of inflammation are discussed.

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.

Anti-inflammatory effect of fibrate protects from cisplatin-induced ARF

Recently, we demonstrated that peroxisome proliferator-activated receptor-α (PPARα) ligand ameliorates cisplatin-induced acute renal failure (ARF) by preventing inhibition of substrate oxidation, and also by preventing apoptosis and necrosis of the proximal tubule (Li S, Bhatt R, Megyesi J, Gokden N, Shah SV, and Portilla D. Am J Physiol Renal Physiol 287: F990–F998, 2004). In the following studies, we examined the protective effect of PPARα ligand on cisplatin-induced inflammatory responses during ARF. Mice subjected to a single intraperitoneal injection of cisplatin developed ARF at day 3. Cisplatin increased mRNA and protein expression of TNF-α, RANTES, and also upregulated endothelial adhesion molecules ICAM-1/VCAM-1 and chemokine receptors CCR1/CCR5. Cisplatin also led to neutrophil infiltration in the corticomedullary region. Pretreatment of wild-type mice with WY-14,643, a fibrate class of PPARα ligands, before cisplatin significantly suppressed cisplatin-induced upregulation of cytokine/chemokine expression, prevented neutrophil accumulation, and ameliorated renal dysfunction. In contrast, treatment with PPARα ligand before cisplatin did not prevent cytokine/chemokine production, neutrophil accumulation, and did not protect kidney function in PPARα null mice. In addition, we observed that cisplatin-induced NF-κB binding activity in nuclear extracts from wild-type mice was markedly reduced by treatment with PPARα ligand. These results demonstrate that PPARα exerts an anti-inflammatory effect in kidney tissue by a mechanism that includes inhibition of NF-κB DNA binding activity, and this effect results in inhibition of neutrophil infiltration, cytokine/chemokine release, and amelioration of cisplatin-induced ARF.

Lessons learned from anti-CD40L treatment in systemic lupus erythematosus patients

The CD40-CD40L system has pleiotropic effects in a variety of cells and biological processes including immune response, thrombosis and atherogenesis. Within the immune system, these molecules represent a critical link between its humoral and cellular arms. As a result of these attributes and based on preclinical data in animals, anti-CD40L antibodies were tested in a variety of immunologic diseases including idiopathic thrombocytopenic purpura, psoriasis, Crohn's disease, systemic lupus erythematosus and transplantation. Phase I/II studies in humans with lupus nephritis demonstrated reduction of anti-double-stranded DNA (anti-dsDNA) antibodies but not of protective antibodies. Reduction of anti-DNA was associated with increased serum complement levels and reduced glomerular inflammation. As a result of thrombotic effects, observed even in patients negative for anti-cardiolipin antibodies, there is a temporary halt on further human studies. The reasons for the prothrombotic effects are not clear at present but may represent effects on platelets and/or the endothelium. In view of the significant immunomodulatory effects of anti-CD40L treatment in patients with lupus nephritis, the increasing realization of the importance of premature atherosclerosis in lupus and an increasing amount of data supporting a role for the CD40-CD40L interactions in this process, inhibition of this pathway deserves further exploration in lupus.

Donor T-cell production of RANTES significantly contributes to the development of idiopathic pneumonia syndrome after allogeneic stem cell transplantation

Idiopathic pneumonia syndrome (IPS) is a major cause of mortality following allogeneic stem cell transplantation (allo-SCT). Clinical and experimental data support a role for conditioning-induced inflammation and alloreactive T-cell responses in IPS pathophysiology, but the mechanisms by which donor leukocytes are ultimately recruited to the lung are not fully understood. RANTES is a chemokine ligand that is up-regulated during inflammation and promotes the recruitment of T cells and macrophages to sites of tissue damage. Using a lethally irradiated murine SCT model (B6 --> B6D2F1), we evaluated the role of donor leukocyte-derived RANTES in the development of IPS. Pulmonary mRNA and protein levels of RANTES were significantly elevated in allo-SCT recipients compared to syngeneic controls and were associated with enhanced mRNA expression of CCR5 and CCR1 and with inflammatory cell infiltration into the lung. Allo-SCT with RANTES-/- donor cells significantly decreased IPS and improved survival. Combinations of allogeneic wild-type or RANTES-/- bone marrow with wild-type or RANTES-/- T cells demonstrated that the expression of RANTES by donor T cells was critical to the development of lung injury after SCT. These data reveal that donor T cells can help regulate leukocyte recruitment to the lung after allo-SCT and provide a possible mechanism through which inflammation engendered by SCT conditioning regimens is linked to allo-specific T-cell responses during the development of IPS.

Transcriptional mechanisms regulating alveolar epithelial cell-specific CCL5 secretion in pulmonary tuberculosis

CCL5 (or RANTES (regulated upon activation, normal T cell expressed and secreted)) recruits T lymphocytes and monocytes. The source and regulation of CCL5 in pulmonary tuberculosis are unclear. Infection of the human alveolar epithelial cell line (A549) by Mycobacterium tuberculosis caused no CCL5 secretion and little monocyte secretion. Conditioned medium from tuberculosis-infected human monocytes (CoMTB) stimulated significant CCL5 secretion from A549 cells and from primary alveolar, but not upper airway, epithelial cells. Differential responsiveness of small airway and normal human bronchial epithelial cells to CoMTB but not to conditioned medium from unstimulated human monocytes was specific to CCL5 and not to CXCL8. CoMTB induced CCL5 mRNA accumulation in A549 cells and induced nuclear translocation of nuclear factor kappaB (NFkappaB) subunits p50, p65, and c-rel at 1 h; nuclear binding of activator protein (AP)-1 (c-Fos, FosB, and c-Jun) at 4-8 h; and binding of NF-interleukin (IL)-6 at 24 h. CCL5 promoter-reporter analysis using deletion and site-specific mutagenesis constructs demonstrated a key role for AP-1, NF-IL-6, and NFkappaB in driving CoMTB-induced promoter activity. The IL-1 receptor antagonist inhibited A549 and small airway epithelial cell CCL5 secretion, gene expression, and promoter activity. CoMTB contained IL-1beta, and recombinant IL-1beta reproduced CoMTB effects. Monocyte alveolar, but not upper airway, epithelial cell networks in pulmonary tuberculosis cause AP-1-, NF-IL-6-, and NFkappaB-dependent CCL5 secretion. IL-1beta is the critical regulator of tuberculosis-stimulated CCL5 secretion in the lung.

Neutralization of interleukin-17 aggravates dextran sulfate sodium-induced colitis in mice

We evaluated the effects of rat anti-mouse IL-17 neutralizing monoclonal antibody (mAb) on the development of dextran sulfate sodium (DSS)-induced colitis. Tissue samples were evaluated by standard immunohistochemical procedure. The mucosal mRNA expression of cytokines was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). In the mice treated with the anti-IL-17 mAb, the body weight was significantly lower, and anal prolapse and colon shortening were apparent. A histological analysis indicated that the anti-IL-17 mAb markedly enhanced the severity of colitis. The mucosal infiltration of CD4-positive helper T cells and CD11b-positive granulocytes-monocytes was increased in the anti-IL-17 mAb-treated mice. Treatment with the anti-IL-17 mAb increased the mucosal expression of mRNAs of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, IL-6, RANTES, and IP-10. Blocking of IL-17 activity in vivo using the anti-IL-17 mAb enhanced the development of DSS-colitis in mice. This suggests an inhibitory role for IL-17 in the development of DSS-colitis.

Expression of RANTES mRNA in skin lesions of feline eosinophilic plaque

One of the mechanisms of eosinophil infiltration is its induction by chemoattractants such as regulated upon activation, normal T-expressed and secreted (RANTES) which is a cysteine-cysteine chemokine that mediates chemotaxis and activation of eosinophils in humans and mice. Skin lesions of feline eosinophilic plaque are characterized by a predominant infiltration of eosinophils. The mechanism(s) of eosinophilic infiltration in the skin and/or mucosa of cats is unknown. It is possible that RANTES is involved. To investigate the presence of RANTES in the skin of cats with eosinophilic plaques and nonaffected skin, we cloned and sequenced the full-length feline RANTES cDNA gene, in order to determine whether it is present in the skin of cats with eosinophilic plaques and/or if it is present in normal adjacent skin. We were able to document the the expression of RANTES mRNAs in skin with feline eosinophilic plaque as well as in normal cat skin. The full-length cDNA sequence of the RANTES gene (742 bp) contained a single open reading frame of 276 bp encoding a protein of 92 amino acids. The amino acid sequence of feline RANTES shared 67 and 74% sequence identity with that of bovine and mouse RANTES genes, respectively. RT-PCR analysis on RANTES mRNA in the skin of cats with eosinophilic plaque revealed that its expression was higher in the eosinophilic plaque skin lesions than in the normal skin. The result suggested that RANTES might play a role to induce eosinophil infiltration in feline eosinophilic plaque lesions.

In vivo evidence for interferon-gamma-mediated homeostatic mechanisms in small intestine of the NHE3 Na+/H+ exchanger knockout model of congenital diarrhea

Mice lacking NHE3, the major absorptive Na(+)/H(+) exchanger in the intestine, are the only animal model of congenital diarrhea. To identify molecular changes underlying compensatory mechanisms activated in chronic diarrheas, cDNA microarrays and Northern blot analyses were used to compare global mRNA expression patterns in small intestine of NHE3-deficient and wild-type mice. Among the genes identified were members of the RegIII family of growth factors, which may contribute to the increased absorptive area, and a large number of interferon-gamma-responsive genes. The latter finding is of particular interest, since interferon-gamma has been shown to regulate ion transporter activities in intestinal epithelial cells. Serum interferon-gamma was elevated 5-fold in NHE3-deficient mice; however, there was no evidence of inflammation, and unlike conditions such as inflammatory bowel disease, levels of other cytokines were unchanged. In addition, quantitative PCR analysis showed that up-regulation of interferon-gamma mRNA was localized to the small intestine and did not occur in the colon, spleen, or kidney. These in vivo data suggest that elevated interferon-gamma, produced by gut-associated lymphoid tissue in the small intestine, is part of a homeostatic mechanism that is activated in response to the intestinal absorptive defect in order to regulate the fluidity of the intestinal tract.

Expression of the chemokine PARC mRNA in bronchoalveolar cells of patients with sarcoidosis

BACKGROUND

Chemotactic cytokines (chemokines) have been recently implicated in the pathogenesis of interstitial lung diseases. A novel chemokine called pulmonary and activation-regulated chemokine (PARC/CCL18), which attracts lymphocytes in vitro, has been detected in the human lung. We have, therefore, investigated PARC mRNA expression in bronchoalveolar lavage fluid (BALF) cells of patients with pulmonary sarcoidosis-a disease characterised by a lymphocytic infiltrate. Further, because several immunomodulators are used in the treatment of sarcoidosis, we have determined the effects of selected drugs on PARC mRNA expression in vitro.

SUBJECTS AND METHODS

BALF cells were obtained by standard bronchoalveolar lavage (BAL) from 30 patients with pulmonary sarcoidosis (S) and 16 control subjects (C). BALF cells from seven subjects were cultured in the presence of dexamethasone (Dx), cyclosporin A (CyA) and pentoxifylline (Px). PARC mRNA expression was semiquantitated by reverse-transcription polymerase chain reaction (RT-PCR) using normalisation to the expression of the beta-actin gene.

RESULTS

PARC mRNA transcripts were detected in 87% of all investigated BALF samples. The expression (ODR PARC/beta-actin; median, the first to the third quartile range) was similar in both groups tested (S, 0.60 (0.50-0.95); C, 0.59 (0.36-0.93); S vs. C: P>0.05). PARC mRNA expression was not associated with the number of lymphocytes in bronchoalveolar space. PARC mRNA expression was significantly suppressed by Dx (P=0.02); CyA and Px showed a moderate inhibitory effect which did not attain significance.

CONCLUSION

mRNA for the chemokine PARC is expressed in the lower respiratory tract in both healthy subjects and patients with pulmonary sarcoidosis. Out of the three immunomodulatory drugs tested, Dx downregulates PARC mRNA expression in BALF cells in vitro.

Chronic antagonism of Mig inhibits cellular infiltration and promotes survival of class II MHC disparate skin allografts

BACKGROUND

The goal of the current study was to test the ability of monokine induced by IFN-gamma (Mig)-specific antibodies to inhibit long-term T cell infiltration into class II major histocompatibility complex (MHC) disparate skin allografts and to test cellular and molecular changes in the graft during the rejection observed following cessation of treatment.

METHODS

C57BL/6 recipients of B6.H-2bm12 skin grafts were treated with normal rabbit serum (NRS) or rabbit Mig antiserum (Mig AS) every other day from day 7 until day 21 posttransplant and then weekly thereafter. Allografts were retrieved during the course of treatment and following cessation. Tissue sections were prepared and stained to compare infiltration by macrophages and CD4+ and CD8+ T cells and to assess collagen deposition in the grafts. RNA was prepared and tested by ribonuclease protection assay for intragraft levels of Mig, monocyte chemotactic protein-1 (MCP-1) and regulated on activation normal T-cell expressed and secreted (RANTES).

RESULTS

T cell and macrophage infiltration into allografts was inhibited and graft survival maintained as long as Mig-specific antibodies were given. Following cessation of treatment, T cells and macrophages infiltrated the allografts. In contrast to the histology of acute rejection observed in allografts from NRS-treated recipients, the resulting rejection of the allografts from Mig AS-treated recipients was accompanied by dense collagen deposition and high level expression of Mig and RANTES.

CONCLUSIONS

Mig directs T cell infiltration into B6.H-2bm12 skin allografts on C57BL/6 recipients. Delayed T cell and macrophage infiltration and rejection of the grafts following cessation of Mig AS treatment results in rejection that is histologically and molecularly distinct from acute rejection.

Quantitative analyses of osteopontin mRNA expression in human proximal tubules isolated from renal biopsy tissue sections of minimal change nephrotic syndrome and IgA glomerulonephropathy patients

Osteopontin (OPN), a secreted phosphoprotein and chemotactic to monocytes/macrophages, is upregulated in renal cortical tubules in a variety of rodent models of renal injury and is believed to possibly have a role in tubulointerstitial injury. We previously reported the establishment of a system for the quantification of messenger RNA (mRNA) expression in isolated rat glomeruli using laser-manipulated microdissection and real-time polymerase chain reaction. This system was applied to human renal biopsy specimens. We quantified OPN mRNA expression in proximal tubules of 5 patients with minimal change nephrotic syndrome (MCNS) and 11 patients with mild immunoglobulin A (IgA) glomerulonephritis. We also examined the correlation between OPN mRNA expression in proximal tubules and clinical data and pathological findings in glomeruli and tubulointerstitial regions. Patients with MCNS showed a positive correlation between OPN mRNA expression in proximal tubules and urinary protein excretion (r = 0.93; P < 0.05), whereas for patients with IgA glomerulonephritis, logarithmic values of OPN mRNA expression in proximal tubules positively correlated with low urinary protein levels (r = 0.72; P < 0.05). Pathological changes, ranging from nonexistent to minor, in glomeruli and tubulointerstitium of these patients with mild IgA glomerulonephritis did not significantly correlate with OPN mRNA expression in proximal tubules. In patients with mild IgA glomerulonephritis, OPN mRNA expression in proximal tubules increased exponentially in response to a small amount of urinary protein (<1.2 g/d).

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.

A critical role for IL-12 in CCR5 induction on T cell receptor-triggered mouse CD4(+) and CD8(+) T cells

Despite increasing evidence for the role of the chemokine system in leukocyte trafficking, the mechanism underlying the induction of chemokine receptors is poorly understood. Here, we investigated how CCR5, a chemokine receptor implicated in T cell migration to inflammatory sites, is induced in the T cell. CCR5 mRNA was hardly detected in resting T cells and marginally induced following T cell receptor (TCR) stimulation. However, TCR-triggered T cells expressed IL-12 receptor, and stimulation with recombinant IL-12 resulted in high levels of CCR5 expression on both CD4(+) and CD8(+) T cells. In contrast, IL-2 failed to up-regulate CCR5 expression. The effect of IL-12 was selective to CCR5 because IL-12 did not up-regulate CXCR3 expression. Surface expression of CCR5 was shown by staining with anti-CCR5 monoclonal antibody. Stimulation of these CCR5-positive T cells with the relevant chemokine MIP-1 alpha elicited Ca(2+) influx, showing that IL-12-induced CCR5 is functional. These results indicate a critical role for IL-12 in the induction of CCR5 on TCR-triggered T cells.

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.

Effects of lipopolysaccharide and cytokines on production of RANTES by cultured human endometrial stromal cells

RANTES (regulated upon activation, normal T cell expressed and secreted), which is a potent chemoattractant for eosinophils, lymphocytes, and monocytes, was recently detected in the human endometrium. The effects of modulators of endometrial function, including lipopolysaccharide (LPS), tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-4 and interferon-gamma (IFN-gamma), on the production of RANTES by endometrial stromal cells (ESC) were examined by an enzyme-linked immunosorbent assay and Northern blot analysis. The concentration of RANTES in the culture media of non-stimulated ESC was below the level of detection. The concentration of RANTES was increased by the addition of TNF-alpha, IL-1beta and LPS. IFN-gamma synergistically enhanced the TNF-alpha- and LPS-induced RANTES expression, but had no effect on the IL-1beta-induced RANTES expression. The TNF-alpha-induced production of RANTES by ESC was inhibited by IL-4. The transcription of RANTES in ESC was also stimulated by TNF-alpha, IL-1beta and LPS in a dose-dependent manner. It is suggested that the LPS and cytokines secreted by the maternal decidual tissue and the developing embryo may regulate the production of RANTES by ESC. The modulation of RANTES concentration in the local environment may contribute to the pathophysiological processes of human reproduction by regulating the immunological reaction at the fetal-maternal interface.

Expression of chemokine genes in murine macrophages infected with Orientia tsutsugamushi

Scrub typhus, caused by Orientia tsutsugamushi infection, is characterized by local as well as systemic inflammatory manifestations. Inflammation is initiated by O. tsutsugamushi-infected macrophages and endothelial cells in the dermis. We investigated the regulation of chemokine induction in macrophage cell line J774A.1 in response to O. tsutsugamushi infection. The mRNAs for macrophage inflammatory proteins 1alpha/beta (MIP-1alpha/beta), MIP-2, and macrophage chemoattractant protein 1 were induced within 30 min, and their levels showed a transitory peak for 3 to 12 h. However, the lymphotactin, eotaxin, gamma interferon-inducible protein 10, and T-cell activation gene 3 mRNAs were not detected by RNase protection assays. Heat-killed O. tsutsugamushi induced a similar extent of chemokine responses. Induction of the chemokine genes was not blocked by the eukaryotic protein synthesis inhibitor cycloheximide, suggesting that de novo synthesis of host cell protein is not required for these transcriptional responses. The induction of chemokine mRNAs by O. tsutsugamushi was blocked by the inhibitors of NF-kappaB activation. Furthermore, O. tsutsugamushi induced the nuclear translocation and activation of NF-kappaB. These results demonstrate that heat-stable molecules of O. tsutsugamushi induce a subset of chemokine genes and that induction involves activation of the transcription factor NF-kappaB.

A central role for CD4(+) T cells and RANTES in virus-induced central nervous system inflammation and demyelination

Infection of C57BL/6 mice with mouse hepatitis virus (MHV) results in a demyelinating encephalomyelitis characterized by mononuclear cell infiltration and white matter destruction similar to the pathology of the human demyelinating disease multiple sclerosis. The contributions of CD4(+) and CD8(+) T cells in the pathogenesis of the disease were investigated. Significantly less severe inflammation and demyelination were observed in CD4(-/-) mice than in CD8(-/-) and C57BL/6 mice (P < or = 0.002 and P < or = 0.001, respectively). Immunophenotyping of central nervous system (CNS) infiltrates revealed that CD4(-/-) mice had a significant reduction in numbers of activated macrophages/microglial cells in the brain compared to the numbers in CD8(-/-) and C57BL/6 mice, indicating a role for these cells in myelin destruction. Furthermore, CD4(-/-) mice displayed lower levels of RANTES (a C-C chemokine) mRNA transcripts and protein, suggesting a role for this molecule in the pathogenesis of MHV-induced neurologic disease. Administration of RANTES antisera to MHV-infected C57BL/6 mice resulted in a significant reduction in macrophage infiltration and demyelination (P < or = 0.001) compared to those in control mice. These data indicate that CD4(+) T cells have a pivotal role in accelerating CNS inflammation and demyelination within infected mice, possibly by regulating RANTES expression, which in turn coordinates the trafficking of macrophages into the CNS, leading to myelin destruction.

Interleukin-8 secretion of cortical tubular epithelial cells is directed to the basolateral environment and is not enhanced by apical exposure to Escherichia coli

In upper urinary tract infections, tubular epithelial cells (TEC) may play a pivotal role in the initiation of the renal inflammatory response. They exert crucial immunological functions such as processing and presentation of foreign antigen, secretion of proinflammatory cytokines (interleukin-6 [IL-6] and tumor necrosis factor alpha) and chemokines (IL-8, MCP-1, ENA-78, and RANTES). Since monolayer cultures are a limited model for polarized tubular epithelial cells, we studied the side-dependent IL-8 secretion of TEC by using cell culture inserts as a basement membrane imitation. Primary cultures of proximal TEC were stimulated with differently fimbriated mutants of Escherichia coli, E. coli LPS, S-fimbria isolates, and IL-1alpha. IL-8 protein was measured by enzyme-linked immunosorbent assay, and IL-8-like biological activity was tested by measuring elastase release from polymorphonuclear cells in supernatants of the upper and lower compartments. IL-8 mRNA was compared by competitive PCR. IL-8 secretion by TEC into the basolateral environment was significantly higher than secretion into the apical compartment, representing the tubular lumen. However, stimulation of IL-8 secretion by TEC was restricted to IL-1alpha and was not inducible by E. coli mutants, S fimbriae, or lipopolysaccharide. With this in vitro model of polarized TEC, we show that luminal contact of TEC with uropathogenic E. coli does not result in enhanced IL-8 secretion. The basolaterally directed production of the neutrophil chemotactic factor IL-8 by TEC after stimulation with IL-1alpha might play an important role in the initiation of inflammatory cell influx into the renal parenchyma.

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.

Overexpression of chemokines, fibrogenic cytokines, and myofibroblasts in human membranous nephropathy

Overexpression of chemokines, fibrogenic cytokines, and myofibroblasts in human membranous nephropathy.

BACKGROUND

Proteinuria plays a central role in the progression of glomerular disease, and there is growing evidence suggesting that it may determine tubular cell activation with release of chemokines and fibrogenic factors, leading to interstitial inflammatory reaction. However, most studies on this subject have been performed in experimental models, and the experience in human kidney biopsies has been scarce. We analyzed the tissue sections of patients with idiopathic membranous nephropathy (IMN), a noninflammatory glomerular disease that may follow a progressive disease with heavy persistent proteinuria, interstitial cell infiltration, and decline of renal function.

METHODS

Paraffin-embedded biopsy specimens from 25 patients with IMN (13 progressive and 12 nonprogressive) were retrospectively studied by immunohistochemistry [monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T-cell expressed and secreted chemokine (RANTES), osteopontin (OPN), platelet-derived growth factor-BB (PD-GF-BB)] and in situ hybridization [MCP-1, RANTES, PDGF-BB, transforming growth factor-beta1 (TGF-beta1)]. Moreover, we studied the presence of myofibroblasts, which were identified by the expression of alpha-smooth muscle actin (alpha-SMA), the monocytes/macrophages (CD68-positive cells), and T-cell infiltration (CD4+ and CD8+ cells). All of the patients were nephrotic and without treatment at time of the biopsy.

RESULTS

A strong up-regulation of MCP-1, RANTES, and OPN expression was observed, mainly in tubular epithelial cells, with a significant major intensity in the progressive IMN patients. A strong correlation between the mRNA expression and the corresponding protein was noted. The presence of these chemokines and OPN was associated with interstitial cell infiltration. TGF-beta and PDGF were also up-regulated, mainly in tubular epithelial cells, with a stronger expression in the progressive IMN, and an association with the presence of myofibroblasts was found.

CONCLUSIONS

Patients with severe proteinuria and progressive IMN have an overexpression in tubular epithelial cells of the chemokines MCP-1, RANTES, and OPN and the profibrogenic cytokines PDGF-BB and TGF-beta. Because this up-regulation was associated with an interstitial accumulation of mononuclear cells and an increase in myofibroblastic activity, it is suggested that those mediators are potential predictors of progression in IMN. Finally, based on experimental data and the findings of this article, we speculate that severe proteinuria is the main factor responsible for the up-regulation of these factors in tubular epithelial cells.

Cloning of bovine RANTES mRNA and its expression and regulation in ovaries in the periovulatory period

RANTES may be one of the chemoattractants involved in stimulating eosinophils and macrophages to migrate selectively into bovine dominant follicles and into developing corpora lutea. We sequenced a 736 bp fragment of the bovine RANTES mRNA encoding the complete protein and defined the ovarian source of RANTES mRNA. As demonstrated by competitive RT-PCR, follicle-derived macrophages showed a 100-1000 times higher RANTES mRNA level compared to unpurified granulosa cells or follicle-derived fibroblasts. By means of in situ hybridization, RANTES mRNA positive macrophages were located in the former thecal layer of the developing corpora lutea.

MIP-1alpha and MCP-1 contribute to crescents and interstitial lesions in human crescentic glomerulonephritis

BACKGROUND

The precise molecular mechanisms of macrophage (Mphi) recruitment and activation in crescentic glomerulonephritis remain to be investigated. We hypothesized that locally produced macrophage inflammatory protein (MIP)-1alpha and monocyte chemoattractant protein (MCP)-1 via the chemokine receptors participate in the pathophysiology of human crescentic glomerulonephritis by recruiting and activating Mphi.

METHODS

We investigated the levels of MIP-1alpha and MCP-1 by enzyme-linked immunosorbent assay (ELISA) in 20 healthy subjects, 20 patients with crescentic glomerulonephritis, and 41 control patients with various other renal diseases. The presence of MIP-1alpha, MCP-1, and the cognate chemokine receptor for MIP-1alpha, CCR5, in the diseased kidneys was evaluated by immunohistochemical and in situ hybridization analyses.

RESULTS

MIP-1alpha-positive cells were mainly detected in crescentic lesions, whereas MCP-1 was mainly in the interstitium. In addition, we detected CCR5-positive cells in diseased glomeruli and interstitium. Urinary MIP-1alpha was detected in crescentic glomerulonephritis, even though it was below detectable levels in healthy subjects and in patients with other renal diseases without crescents. Urinary MIP-1alpha levels in the patients with crescentic glomerulonephritis were well correlated with the percentage of cellular crescents and the number of CD68-positive infiltrating cells and CCR5-positive cells in the glomeruli. However, urinary MCP-1 levels were well correlated with the percentage of both total crescents and fibrocellular/fibrous crescents and the number of CD68-positive infiltrating cells in the interstitium. Moreover, elevated urinary levels of both MIP-1alpha and MCP-1 dramatically decreased during glucocorticoid therapy-induced convalescence.

CONCLUSIONS

These observations suggest that locally produced MIP-1alpha may be involved in the development of cellular crescents in the acute phase via CCR5 and that MCP-1 may be involved mainly in the development of interstitial lesions in the chronic phase when fibrocellular/fibrous crescents are present, possibly through Mphi recruitment and activation.

Expression profile of extracellular matrix and its regulatory proteins during the process of interstitial fibrosis after anti-glomerular basement membrane antibody-induced glomerular sclerosis in Sprague-Dawley rats

Anti-glomerular basement membrane (GBM) nephritis in Sprague-Dawley (SD) rats was characterized by development of marked glomerular sclerosis and tubulointerstitial fibrosis. To elucidate sequential change of the glomerular sclerosis and tubulointerstitial fibrosis, accumulation and mRNA expression of extracellular matrix (ECM) components and transforming growth factor (TGF)-beta were examined in the glomerulus and cortex during the disease course by histology, immunostaining and ribonuclease protection assay. Mild proliferative and degenerative lesions appeared in the glomeruli by day 15 after anti-GBM antibody binding to GBM and progressed to glomerular sclerotic lesion thereafter. Conversely, interstitial change was first recognized by infiltration of mononuclear cells after day 20, followed by marked accumulation of ECM and tubular degeneration. The interstitial fibrosis was induced without apparent binding of anti-GBM antibody to tubular basement membrane. Accumulation of fibronectin, collagen type I and type IV was noted in the interstitium by immunofluorescence microscopy in association with enhanced expression of mRNA for these ECM components and their regulatory molecules such as matrix metalloproteinase (MMP2), tissue inhibitor of metalloproteinase (TIMP)-1 and TGF-beta1 both in glomeruli and cortex. The glomerular expression of these mRNA increased apparently by day 15 and reached a plateau or a peak at day 20. The expression of the same mRNA increased gradually from day 15 to day 29 in the cortex. These observations show that interstitial fibrosis follows glomerular sclerosis after anti-GBM antibody injection in SD rats, suggesting that at least a part of the mechanism for ECM accumulation in the glomerulus and interstitium is essentially the same in terms of composition of ECM and expression of its regulatory molecules.

Chemokine gene expression during Pneumocystis carinii-driven pulmonary inflammation

Severe combined immunodeficient (SCID) mice lack functional lymphocytes and therefore develop Pneumocystis carinii pneumonia. However, when infected SCID mice are immunologically reconstituted with congenic spleen cells, a protective inflammatory cascade is initiated. Proinflammatory cytokines are produced, and lymphocytes and macrophages are recruited specifically to alveolar sites of infection. Importantly, uninfected regions of the lung remain free from inflammatory involvement, suggesting that there are specific mechanisms that limit inflammation in the infected lung. Therefore, to determine whether chemokines are involved in targeting the P. carinii-driven inflammatory response, steady-state mRNA levels of several chemokines were measured in the lungs of both reconstituted and nonreconstituted P. carinii-infected SCID mice. Despite significant organism burdens in the lungs of 8- and 10-week-old SCID mice, there was no evidence of elevated chemokine gene expression, which is consistent with the lack of an inflammatory response in these animals. However, when 8-week-old infected SCID mice were immunologically reconstituted, signs of focal pulmonary inflammation were observed, and levels of RANTES, MCP-1, lymphotactin, MIP-1alpha, MIP-1beta, and MIP-2 mRNAs were all significantly elevated. Chemokine mRNA abundance was elevated at day 10 postreconstitution (PR), was maximal at day 12 PR, and returned to baseline by day 22 PR. In situ hybridization demonstrated that during the peak of inflammation, RANTES gene expression was localized to sites of inflammatory cell infiltration and P. carinii infection. Thus, these observations indicate that chemokines play a role in the focal targeting of inflammatory cell recruitment to sites of P. carinii infection after the passive transfer of lymphocytes to the host.

Cyclooxygenase metabolites mediate glomerular monocyte chemoattractant protein-1 formation and monocyte recruitment in experimental glomerulonephritis

BACKGROUND

Monocyte chemoattractant protein-1 (MCP-1) has been shown to play a significant role in the recruitment of monocytes/macrophages in experimental glomerulonephritis. Whereas a number of inflammatory mediators have been characterized that are involved in the expression of MCP-1 in renal disease, little is known about repressors of chemokine formation in vivo. We hypothesized that cyclooxygenase (COX) products influence the formation of MCP-1 and affect inflammatory cell recruitment in glomerulonephritis.

METHODS

The effect of COX inhibitors was evaluated in the antithymocyte antibody model and an anti-glomerular basement membrane model of glomerulonephritis. Rats were treated with the COX-1/COX-2 inhibitor indomethacin and the selective COX-2 inhibitors meloxicam and SC 58125. Animals were studied at 1 hour, 24 hours, and 5 days after induction of the disease.

RESULTS

Indomethacin, to a lesser degree the selective COX-2 inhibitors, enhanced glomerular MCP-1 and RANTES mRNA levels. Indomethacin enhanced glomerular monocyte chemoattractant activity an the infiltration of monocytes/macrophages at 24 hours and 5 days.

CONCLUSIONS

Our studies demonstrate that COX products may serve as endogenous repressors of MCP-1 formation in experimental glomerulonephritis. The data suggest that COX-1 and COX-2 products mediate these effects differently because the selective COX-2 inhibitors had less influence on chemokine expression.

Gene expression of CC chemokines in experimental acute tubulointerstitial nephritis

The infiltration of mononuclear leukocytes into glomeruli or the interstitium is a feature in most forms of glomerular diseases. CC chemokines, mostly chemoattractants for mononuclear leukocytes, are molecules that are potentially responsible for the recruitment of these cells in the kidney. We previously reported that the gene expression of six CC chemokines-MCP-1, MCP-3, MIP-1alpha, MIP-1beta, RANTES, and TCA3-was enhanced in a rat model of crescentic glomerulonephritis, the most severe form of glomerulonephritis. In this study we analyzed their gene expression in a model of another type of kidney disease, acute nephrosis accompanied by tubulointerstitial lesions, which is induced by an injection of puromycin aminonucleoside. Because leukocyte infiltration in this model is much more prominent in the interstitium than in glomeruli, we analyzed their gene expression in the renal cortex. On day 3, when the level of urinary protein was slightly but significantly increased but the number of interstitial leukocytes was unchanged, the enhanced expression of mRNAs for MCP-1, MCP-3, and TCA3 was observed. On day 5, the numbers of interstitial monocytes and lymphocytes significantly increased, and the levels of the mRNA expression of the above chemokines were still higher than the control animals, whereas the levels of mRNAs for MIP- 1alpha, MIP-1beta, and RANTES were not higher or were only slightly higher than the control ones. These results suggest that multiple CC chemokines may play a role in the recruitment of leukocytes in this model and that the expression pattern of CC chemokines depends on the type of kidney injury.

Activated murine B lymphocytes and dendritic cells produce a novel CC chemokine which acts selectively on activated T cells

Genes were isolated using the suppression subtractive hybridization method by stimulation of pro/pre B cells with anti-CD40 and interleukin (IL)-4 to mature S mu-Sepsilon-switched cells. One of the strongly upregulated genes encodes a novel murine CC chemokine we have named ABCD-1. The ABCD-1 gene has three exons separated by 1. 2- and 2.7-kb introns. It gives rise to a 2.2-kb transcript containing an open reading frame of 276 nucleotides. Two polyadenylation sites are used, giving rise to cDNAs with either 1550 or 1850 bp of 3' untranslated regions. The open reading frame encodes a 24 amino acid-long leader peptide and a 68 amino acid-long mature protein with a predicted molecular mass of 7.8 kD. ABCD-1 mRNA is found in highest quantities in activated splenic B lymphocytes and dendritic cells. Little chemokine mRNA is present in lung, in unstimulated splenic cells, in thymocytes, and in lymph node cells. No ABCD-1 mRNA is detected in bone marrow, liver, kidney, or brain, in peritoneal exudate cells as well as in the majority of all unstimulated B lineage cells tested. It is also undetectable in Concanavalin A-activated/IL-2-restimulated splenic T cells, and in bone marrow-derived IL-2-induced natural killer cells and IL-3-activated macrophages. Recombinant ABCD-1 revealed a concentration-dependent and specific migration of activated splenic T lymphoblasts in chemotaxis assays. FACS(R) analyses of migrated cells showed no preferential difference in migration of CD4(+) versus CD8(+) T cell blasts. Murine as well as human T cells responded to ABCD-1. Freshly isolated cells from bone marrow, thymus, spleen, and lymph node, IL-2-activated NK cells, and LPS-stimulated splenic cells, all did not show any chemotactic response. Thus, ABCD-1 is the first chemokine produced in large amounts by activated B cells and acting selectively on activated T lymphocytes. Therefore, ABCD-1 is expected to play an important role in the collaboration of dendritic cells and B lymphocytes with T cells in immune responses.

Chemokines: understanding their role in T-lymphocyte biology

The chemokines are a complex superfamily of small, secreted proteins that were initially characterized through their chemotactic effects on a variety of leucocytes. The superfamily is divided into families based on structural and genetic considerations and have been termed the CXC, CC, C and CX3C families. Chemokines from these families have a key role in the recruitment and function of T lymphocytes. Moreover, T lymphocytes have also been identified as a source of a number of chemokines. T lymphocytes also express most of the known CXC and CC chemokine receptors to an extent that depends on their state of activation/differentiation and/or the activating stimuli. The expression of two chemokine receptors, namely CXCR4 and CCR5, together with the regulated production of their respective ligands, appears to be extremely important in determining sensitivity of T cells to HIV-1 infection. The intracellular events which mediate the effects of chemokines, particularly those elicited by the CC chemokine RANTES, include activation of both G-protein- and protein tyrosine kinase-coupled signalling pathways. The present review describes our current understanding of the structure and expression of chemokines and their receptors, the effects of chemokines on T-cell function(s), the intracellular signalling pathways activated by chemokines and the role of certain chemokines and chemokine receptors in determining sensitivity to HIV-1 infection.

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.

Selective chemokine mRNA expression following brain injury

Injury in non-neuronal tissues stimulates chemokine expression leading to recruitment of inflammatory cells responsible for orchestration of repair processes. The signals involved in directing repair of damage to the brain are less well understood. We hypothesized that following brain injury, chemokines are expressed and regulate the rate and pattern of inflammatory cell accumulation. The two chemokine subfamilies are alpha(alpha)-chemokines, which primarily function as neutrophil chemoattractants, and the beta(beta)-chemokines, which function primarily as monocyte chemoattractants. We assessed alpha and beta chemokine mRNA expression patterns and leukocyte accumulation following a cerebral cortical lesion. Cortical lesions were produced with and without addition of endotoxin, Escherichia coli lipopolysaccharide (LPS), which stimulates cytokine expression. We studied the expression of the beta-chemokines: monocyte chemoattractant protein (gene product JE; MCP-1/JE), macrophage inflammatory protein-1 alpha and beta (MIP-1alpha and MIP-1beta), and the regulated upon activation normal T expressed and secreted chemokine (RANTES) as well as the alpha-chemokines: interferon-gamma-inducible protein (IP-10) and N51/KC (KC; a murine homologue of MIP-2). Changes in gene expression were analyzed by Northern analysis at different time points following injury. Leukocyte and macrophage densities were analyzed by immunohistochemistry at the same time intervals. All chemokines were elevated following cortical injury/endotoxin. MCP-1 and MIP-1alpha were elevated at 2 h and peaked 6 h, MIP-1beta peaked at 6 h, but declined more rapidly than MCP-1 or MIP-1alpha, and IP-10 peaked at 6 h and showed the most rapid decline. KC was elevated at 1 h, and peaked at 6 h following LPS. RANTES was elevated at 1 h and achieved a plateau level between 6 and 18 h, then declined. In contrast, sterile injuries produced in the absence of endotoxin only induced the mRNA of the beta-chemokine MCP-1, and its expression was delayed compared to the cortical injury/endotoxin group. The presence of chemokine message as early as 1 h indicates that expression of this class of molecules is an early response in the repair process following traumatic brain injury. Macrophage/microglia accumulation occurred more rapidly, activated microglia further from the lesion border, and more cells accumulated in cortical injury/endotoxin than in cortical lesions produced under sterile conditions. Thus, there was a positive correlation between beta-chemokine expression and the number of beta-chemokine responsive cells (i.e. microglia) accumulating in injury sites. This is the first comprehensive study using a panel of chemokine probes and specific marcophage/microglial markers to study in vivo activation of the brain following injury. Our data show that the brain is capable of expression of multiple chemokine genes upon appropriate stimulation (e.g. LPS-treatment). The gradient of microglial activation is consistent with physical damage stimulating release of chemokines that diffuse from the injury site. These data strongly suggest that chemokines are instrumental in the initiation of repair processes following brain injury.

Cytokines as targets for the inhibition of eosinophilic inflammation

Eosinophilic inflammation is thought to play a central role in the pathogenesis of asthma. The immunoregulatory effects of interleukin (IL)-4, IL-5 and immunoglobulin (Ig)E suggest that these molecules play key roles in the effector function of eosinophils and mast cells. IL-4 regulates the development of CD4+ TH2-type cells, which elicit essential signals through IL-4 and IL-5 for the regulation of IgE production and eosinophilia, respectively. IL-5-regulated pulmonary eosinophilia and airways dysfunction can also occur independently of IL-4 and allergen-specific Igs. Such IL-4-independent pathways may also play a substantive role in the aetiology of asthma. Thus, evidence is now emerging that allergic airways disease is regulated by humoral and cell-mediated components. The essential and specific role of IL-5 in regulating eosinophilia, and the subsequent involvement of this leukocyte in the induction of lung damage and airways dysfunction, identifies IL-5 as a primary therapeutic target for the relief of airways dysfunction in asthma.

Expression of chemokine RANTES and production of monoclonal antibodies

RANTES was first identified as a cDNA in a search for genes expressed late (3-5 days) after T-cell activation. Definition of RANTES function depended on the generation of protein. This chapter describes the various techniques used to make recombinant RANTES protein, to test its activity, and to generate monoclonal antibodies to assess RANTES protein cell distribution.

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.

Expression of chemokine genes during rejection and long-term acceptance of cardiac allografts

Chemokines are cytokines with chemoattractant properties for leukocytes. They may play a critical role in directing leukocytes to graft sites and in amplifying intragraft inflammation during rejection. Previous studies have tested the intragraft expression of chemokine genes during the rejection of allogeneic skin grafts in mice. In the current study, we used a heterotopic heart transplant model in mice to test the intragraft expression of these genes in nonrejecting cardiac isografts, rejecting cardiac allografts, and cardiac allografts that were accepted due to immunosuppression with gallium nitrate. With the exception of low levels of interleukin-1beta and JE, intragraft expression of the the proinflammatory cytokine genes was not observed in either isografts or native heart. Two distinct patterns of chemokine mRNA were observed in the rejecting cardiac allografts. Intra-allograft expression of interleukin-1beta, interferon-gamma-inducible protein, JE, and KC was prominent by day 3 after transplantation. The expression of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and regulated upon activation, normal T cell expressed and secreted (RANTES) was at low or undetectable levels at day 3 after transplantation but at high levels by day 8 after transplantation. Sixty days after transplantation, intra-allograft expression of chemokines in hearts from gallium nitrate-treated recipients indicated low levels of MIP-1alpha, MIP-1beta, and KC but high levels of interferon-gamma-inducible protein and RANTES.