[Show abstract][Hide abstract] ABSTRACT: Diabetes is associated with activation of the polyol pathway, in which glucose is converted to sorbitol by aldose reductase. Previous studies focused on the role of sorbitol in mediating diabetic complications. However, in the proximal tubule, sorbitol can be converted to fructose, which is then metabolized largely by fructokinase, also known as ketohexokinase, leading to ATP depletion, proinflammatory cytokine expression, and oxidative stress. We and others recently identified a potential deleterious role of dietary fructose in the generation of tubulointerstitial injury and the acceleration of CKD. In this study, we investigated the potential role of endogenous fructose production, as opposed to dietary fructose, and its metabolism through fructokinase in the development of diabetic nephropathy. Wild-type mice with streptozotocin-induced diabetes developed proteinuria, reduced GFR, and renal glomerular and proximal tubular injury. Increased renal expression of aldose reductase; elevated levels of renal sorbitol, fructose, and uric acid; and low levels of ATP confirmed activation of the fructokinase pathway. Furthermore, renal expression of inflammatory cytokines with macrophage infiltration was prominent. In contrast, diabetic fructokinase-deficient mice demonstrated significantly less proteinuria, renal dysfunction, renal injury, and inflammation. These studies identify fructokinase as a novel mediator of diabetic nephropathy and document a novel role for endogenous fructose production, or fructoneogenesis, in driving renal disease.
Journal of the American Society of Nephrology 05/2014; · 9.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Excessive dietary fructose intake may have an important role in the current epidemics of fatty liver, obesity and diabetes as its intake parallels the development of these syndromes and because it can induce features of metabolic syndrome. The effects of fructose to induce fatty liver, hypertriglyceridemia and insulin resistance, however, vary dramatically among individuals. The first step in fructose metabolism is mediated by fructokinase (KHK), which phosphorylates fructose to fructose-1-phosphate; intracellular uric acid is also generated as a consequence of the transient ATP depletion that occurs during this reaction. Here we show in human hepatocytes that uric acid up-regulates KHK expression thus leading to the amplification of the lipogenic effects of fructose. Inhibition of uric acid production markedly blocked fructose-induced triglyceride accumulation in hepatocytes in vitro and in vivo. The mechanism whereby uric acid stimulates KHK expression involves the activation of the transcription factor ChREBP, which, in turn, results in the transcriptional activation of KHK by binding to a specific sequence within its promoter. Since subjects sensitive to fructose often develop phenotypes associated with hyperuricemia, uric acid may be an underlying factor in sensitizing hepatocytes to fructose metabolism during the development of fatty liver.
PLoS ONE 10/2012; 7(10):e47948. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fructose intake from added sugars correlates with the epidemic rise in obesity, metabolic syndrome, and nonalcoholic fatty liver disease. Fructose intake also causes features of metabolic syndrome in laboratory animals and humans. The first enzyme in fructose metabolism is fructokinase, which exists as two isoforms, A and C. Here we show that fructose-induced metabolic syndrome is prevented in mice lacking both isoforms but is exacerbated in mice lacking fructokinase A. Fructokinase C is expressed primarily in liver, intestine, and kidney and has high affinity for fructose, resulting in rapid metabolism and marked ATP depletion. In contrast, fructokinase A is widely distributed, has low affinity for fructose, and has less dramatic effects on ATP levels. By reducing the amount of fructose for metabolism in the liver, fructokinase A protects against fructokinase C-mediated metabolic syndrome. These studies provide insights into the mechanisms by which fructose causes obesity and metabolic syndrome.
Proceedings of the National Academy of Sciences 02/2012; 109(11):4320-5. · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Crescentic glomerulonephritis (GN) in Wistar-Kyoto rats progresses to lethal kidney failure by macrophage (Mφ)-mediated mechanisms. Mφs in nephritic glomeruli express adenosine A(2A) receptors (A(2A)Rs), the activation of which suppresses inflammation. Here, we pharmacologically activated the A(2A)Rs with a selective agonist, CGS 21680, and inactivated them with a selective antagonist, ZM241385, to test the effects on established GN. When activation was delayed until antiglomerular basement membrane GN and extracellular matrix deposition were established, glomerular Mφ infiltration was reduced by 83%. There was also a marked improvement in glomerular lesion histology, as well as decreased proteinuria. A(2A)R activation significantly reduced type I, III, and IV collagen deposition, and E-cadherin expression was restored in association with a reduction of α-smooth muscle actin-positive myofibroblasts in the interstitium and glomeruli. In contrast, pharmacological inactivation of A(2A)Rs increased glomerular crescent formation, type I, III, and IV collagen expression, and enhanced E-cadherin loss. Activation of A(2A)Rs suppressed the expression of the Mφ-linked glomerular damage mediators, transforming growth factor-β, osteopontin-1, thrombospondin-1, and tissue inhibitor of metalloproteinase-1. Thus, A(2A)R activation can arrest GN and prevent progressive fibrosis in established pathological lesions.
Kidney International 04/2011; 80(4):378-88. · 8.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Interstitial fibrosis plays a major role in progression of renal diseases. Oncostatin M (OSM) is a cytokine that regulates cell survival, differentiation, and proliferation. Renal tissue from patients with chronic obstructive nephropathy was examined for OSM expression. The elevated levels in diseased human kidneys suggested possible correlation between OSM level and kidney tissue fibrosis. Indeed, unilateral ureteral obstruction (UUO), a model of renal fibrosis, increased OSM and OSM receptor (OSM-R) expression in a time-dependent manner within hours following UUO. In vitro, OSM overexpression in tubular epithelial cells (TECs) resulted in epithelial-myofibroblast transdifferentiation. cDNA microarray technology identified up-regulated expression of immune modulators in obstructed compared with sham-operated kidneys. In vitro, OSM treatment up-regulated CC chemokine ligand CCL7, and CXC chemokine ligand (CXCL)-14 mRNA in kidney fibroblasts. In vivo, treatment of UUO mice with neutralizing anti-OSM antibody decreased renal chemokines expression. In conclusion, OSM is up-regulated in kidney tissue early after urinary obstruction. Therefore, OSM might play an important role in initiation of renal fibrogenesis, possibly by inducing myofibroblast transdifferentiation of TECs as well as leukocyte infiltration. This process may, in turn, contribute in part to progression of obstructive nephropathy and makes OSM a promising therapeutic target in renal fibrosis.
Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 07/2010; 30(7):513-23. · 1.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Only a few specific chemokines that mediate interactions between inflammatory and satellite cells in muscle regeneration have been identified. The chemokine CXCL16 differs from other chemokines because it has both a transmembrane region and active, soluble chemokine forms. Indeed, we found increased expression of CXCL16 and its receptor, CXCR6, in regenerating myofibers. Muscle regeneration in CXCL16-deficient (CXCL16KO) mice was severely impaired compared with regeneration in wild-type mice. In addition, there was decreased MyoD and myogenin expression in regenerating muscle in CXCL16KO mice, indicating impaired satellite cell proliferation and differentiation. After 1 month, new myofibers in CXCL16KO mice remained significantly smaller than those in muscle of wild-type mice. To understand how CXCL16 regulates muscle regeneration, we examined cells infiltrating injured muscle. There were more infiltrating neutrophils and fewer macrophages in injured muscle of CXCL16KO mice compared with events in wild-type mice. Moreover, absence of CXCL16 led to different expression of cytokines/chemokines in injured muscles: mRNAs of macrophage-inflammatory protein (MIP)-1alpha, MIP-1beta, and MIP-2 were increased, whereas regulated on activation normal T cell expressed and secreted, T-cell activation-3, and monocyte chemoattractant protein-1 mRNAs were lower compared with results in muscles of wild-type mice. Impaired muscle regeneration in CXCL16KO mice also resulted in fibrosis, which was linked to transforming growth factor-beta1 expression. Thus, CXCL16 expression is a critical mediator of muscle regeneration, and it suppresses the development of fibrosis.
American Journal Of Pathology 11/2009; 175(6):2518-27. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In immune-induced inflammation, leukocytes are key mediators of tissue damage. Since A(2A) adenosine receptors (A(2A)Rs) are endogenous suppressors of inflammation, we examined cellular and molecular mechanisms of kidney damage to determine if selective activation of A(2A)R would suppress inflammation in a rat model of glomerulonephritis. Activation of A(2A)R reduced the degree of kidney injury in both the acute inflammatory phase and the progressive phase of glomerulonephritis. This protection against acute and chronic inflammation was associated with suppression of the glomerular expression of the MDC/CCL22 chemokine and down-regulation of MIP-1alpha/CCL3, RANTES/CCL5, MIP-1beta/CCL4, and MCP-1/CCL2 chemokines. The expression of anti-inflammatory cytokines, interluekin (IL)-4 and IL-10, also increased. The mechanism for these anti-inflammatory responses to the A(2A)R agonist was suppression of macrophages function. A(2A)R expression was increased in macrophages, macrophage-derived chemokines were reduced in response to the A(2A)R agonist, and chemokines not expressed in macrophages did not respond to A(2A)R activation. Thus, activation of the A(2A)R on macrophages inhibits immune-associated inflammation. In glomerulonephritis, A(2A)R activation modulates inflammation and tissue damage even in the progressive phase of glomerulonephritis. Accordingly, pharmacological activation of A(2A)R could be developed into a novel treatment for glomerulonephritis and other macrophage-related inflammatory diseases.
The FASEB Journal 03/2008; 22(2):445-54. · 5.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Lung cancer is the leading cause of cancer mortality in the United States. Despite advances made over the past decades, the overall survival of patients with lung cancer remains dismal. Here we report novel G-quartet oligodeoxynucleotides (GQ-ODN) that were designed to selectively target signal transducer and activator of transcription 3 (Stat3), in the treatment of human non-small cell lung cancer (NSCLC). The objective of this study was to evaluate the effects of two novel GQ-ODN STAT3 inhibitors, T40214 and T40231, on NSCLC bearing nude mice. NSCLC bearing nude mice were assigned to 5 groups, which were treated by vehicle, control ODN, T40214, T40231, and Paclitaxel, respectively. Tumors were measured, isolated and analyzed using Western blotting, immuno-histochemistry, RPA and TUNEL. Results show that GQ-ODN T40214 and T40231 significantly suppress the growth of NSCLC tumors in nude mice by selectively inhibiting the activation of Stat3 and its downstream proteins Bcl-2, Bcl-xL, Mcl-1, survivin, VEGF, Cyclin D1 and c-myc; thereby, promoting apoptosis and reducing angiogenesis and cell proliferation. These findings validate Stat3 as an important molecular target for NSCLC therapy and demonstrate the efficacy of GQ-ODN in inhibiting Stat3 phosphorylation.
International Journal of Oncology 08/2007; 31(1):129-36. · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemokines recruit and activate leukocytes during inflammation. CXCL16 is a recently discovered chemokine that is expressed as a transmembrane protein that is cleaved to form the active, soluble chemokine. We analyzed the role of CXCL16 in the development of inflammation and in the progression of the anti-glomerular basement membrane (GBM) antibody-induced experimental glomerulonephritis in Wistar-Kyoto rats. CXCL16 was expressed in glomerular endothelial cells and mediated adhesion of macrophages expressing CXCL16 and its cognate receptor, CXCR6. Glomerular infiltrates displayed a strong migratory response to soluble CXCL16. Soluble CXCL16 and its receptor CXCR6 were induced in nephritic glomeruli throughout the disease, and CXCL16 expression correlated with the up-regulation of ADAM10, suggesting that this disintegrin and metalloproteinase mediates the chemokine activity of CXCL16. Blocking CXCL16 in the acute inflammatory phase or progressive phase of established glomerulonephritis significantly attenuated monocyte/macrophage infiltration and glomerular injury; proteinuria also improved. We conclude that CXCL16/CXCR6 plays a critical role in stimulating leukocyte influx, which causes glomerular damage during anti-GBM glomerulonephritis. Blocking CXCL16 actions limits the progression of anti-GBM glomerulonephritis even when the disease is established.
American Journal Of Pathology 06/2007; 170(5):1485-96. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Obesity is associated with chronic inflammation, which includes increased macrophage accumulation in adipose tissue (AT) and upregulation of chemokines and cytokines. T cells also play important roles in chronic inflammatory diseases such as atherosclerosis but have not been well studied in obesity.
Flow cytometric analysis showed higher numbers of T cells and macrophages in AT of diet-induced obese insulin-resistant male mice than in lean mice and obese females (P<0.05). RNase protection assay, ELISA, and flow cytometry indicated gender-dependent upregulation of mRNA and protein levels of regulated on activation, normal T cell expressed and secreted (RANTES) and its receptor CCR5 in AT of obese mice. Adipocytes, stromal/vascular cells from mouse AT, and human and murine adipocytes expressed RANTES. RANTES mRNA levels were negatively correlated with adiponectin in mouse AT. Adiponectin-deficient mice fed high-fat diet showed higher RANTES mRNA levels in AT than wild-type mice. Activated T cells coincubated with preadipocytes in vitro significantly suppressed preadipocyte-to-adipocyte differentiation. Obese humans with metabolic syndrome had higher mRNA levels of RANTES and CCR5 in subcutaneous AT than lean humans. RANTES and CCR5 mRNA levels were significantly higher in visceral than subcutaneous AT of morbidly obese humans. RANTES mRNA levels were positively correlated with CD3 and CD11b in human visceral AT.
Obesity is associated with increased accumulation of T cells and macrophages in AT, which may play important roles in obesity-related disease by influencing preadipocyte/adipocyte functions. RANTES is an adipokine that is upregulated in AT by obesity in both mice and humans.
[Show abstract][Hide abstract] ABSTRACT: The chemokine monocyte chemoattractant protein (MCP)-1 has been implicated in the monocyte/macrophage infiltration that occurs during tubulointerstitial nephritis (TIN). We investigated the role of MCP-1 in rats with TIN by administering a neutralizing anti-MCP-1 antibody (Ab). We observed significantly reduced macrophage infiltration and delayed neutrophil clearance in the kidneys of TIN model rats treated with the anti-MCP-1 Ab. To exclude the possibility that an observed immune complex could affect the resolution of apoptotic neutrophils via the Fc receptor, TIN model rats were treated with a peptide-based MCP-1 receptor antagonist (RA). The MCP-1 RA had effects similar to those of the anti-MCP-1 Ab. In addition, MCP-1 did not affect macrophage-mediated phagocytosis of neutrophils in vitro. Deposition of the anti-MCP-1 Ab in rat kidneys resulted from its binding to heparan sulfate-immobilized MCP-1, as demonstrated by the detection of MCP-1 in both pull-down and immunoprecipitation assays. We conclude that induction of chemokines, specifically MCP-1, in TIN corresponds with leukocyte infiltration and that the anti-MCP-1 Ab formed an immune complex with heparan sulfate-immobilized MCP-1 in the kidney. Antagonism of MCP-1 in TIN by Ab or RA may alter the pathological process, most likely through delayed removal of apoptotic neutrophils in the inflammatory loci.
American Journal Of Pathology 10/2005; 167(3):637-49. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Angiogenesis plays a key role in promoting tumorigenesis and metastasis. Several antiangiogenic factors have been shown to inhibit tumor growth in animal models. Understanding their mechanism of action would allow for better therapeutic application. 16-kDa prolactin (PRL), a NH2-terminal natural breakdown fragment of the intact 23-kDa PRL, exerts potent antiangiogenic and antitumor activities. The signaling mechanism involved in 16-kDa PRL action in endothelial cells remains unclear. One of the actions of 16-kDa PRL is to attenuate the production of nitric oxide (NO) through the inhibition of inducible NO synthase (iNOS) expression in endothelial cells. To delineate the signaling mechanism from 16-kDa PRL, we examined the effect of 16-kDa PRL on interleukin IL-1beta-inducible iNOS expression, which is regulated by two parallel pathways, one involving IFN regulatory factor 1 (IRF-1) and the other nuclear factor-kappaB (NF-kappaB). Our studies showed that 16-kDa PRL specifically blocked IRF-1 but not NF-kappaB signaling to the iNOS promoter. We found that IL-1beta regulated IRF-1 gene expression through stimulation of p38 mitogen-activated protein kinase (MAPK), which mediated signal transducer and activator of transcription 1 (Stat1) serine phosphorylation and Stat1 nuclear translocation to activate the IRF-1 promoter. 16-kDa PRL effectively inhibited IL-1beta-inducible p38 MAPK phosphorylation, resulting in blocking Stat1 serine phosphorylation, its subsequent nuclear translocation and activation of the Stat1 target gene IRF-1. Thus, 16-kDa PRL inhibits the p38 MAPK/Stat1/IRF-1 pathway to attenuate iNOS/NO production in endothelial cells.
Cancer Research 10/2005; 65(17):7984-92. · 9.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Acupuncture as a complex therapeutic system has been used to treat a variety of diseases and pathological conditions. Although the exact mechanism(s) of acupuncture remains unknown, some evidence suggests a mechanism initially involving signal transduction through connective tissue, with secondary involvement of other systems including the nervous system. Acupuncture has become increasingly popular in the Western countries as a therapy for pain and several chronic disorders difficult to manage with conventional treatments. Acupuncture and acupuncture-like somatic nerve stimulation have been used in different kidney diseases and several complications related to them. The effect of acupuncture techniques in some kidney diseases is reviewed on the basis of clinical reports as well as mechanisms that may possibly explain the beneficial effects mediated by acupressure/acupuncture. The potential effect of acupressure techniques in renal inflammation and whether these effects could be mediated through the newly identified cholinergic anti-inflammatory pathway are discussed.
[Show abstract][Hide abstract] ABSTRACT: The great similarity of the genomes of humans and other species stimulated us to search for genes regulated by elements associated with human uniqueness, such as the mind-body interaction. DNA microarray technology offers the advantage of analyzing thousands of genes simultaneously, with the potential to determine healthy phenotypic changes in gene expression. The aim of this study was to determine the genomic profile and function of neutrophils in Falun Gong (FLG, an ancient Chinese Qigong) practitioners, with healthy subjects as controls.
Six (6) Asian FLG practitioners and 6 Asian normal healthy controls were recruited for our study. The practitioners have practiced FLG for at least 1 year (range, 1-5 years). The practice includes daily reading of FLG books and daily practice of exercises lasting 1-2 hours. Selected normal healthy controls did not perform Qigong, yoga, t'ai chi, or any other type of mind-body practice, and had not followed any conventional physical exercise program for at least 1 year. Neutrophils were isolated from fresh blood and assayed for gene expression, using microarrays and RNase protection assay (RPA), as well as for function (phagocytosis) and survival (apoptosis).
The changes in gene expression of FLG practitioners in contrast to normal healthy controls were characterized by enhanced immunity, downregulation of cellular metabolism, and alteration of apoptotic genes in favor of a rapid resolution of inflammation. The lifespan of normal neutrophils was prolonged, while the inflammatory neutrophils displayed accelerated cell death in FLG practitioners as determined by enzyme-linked immunosorbent assay. Correlating with enhanced immunity reflected by microarray data, neutrophil phagocytosis was significantly increased in Qigong practitioners. Some of the altered genes observed by microarray were confirmed by RPA.
Qigong practice may regulate immunity, metabolic rate, and cell death, possibly at the transcriptional level. Our pilot study provides the first evidence that Qigong practice may exert transcriptional regulation at a genomic level. New approaches are needed to study how genes are regulated by elements associated with human uniqueness, such as consciousness, cognition, and spirituality.
The Journal of Alternative and Complementary Medicine 03/2005; 11(1):29-39. · 1.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A basic conservation of cell migration guidance mechanisms in the nervous and immune systems was proposed when Slit, known for its role in axon guidance, was found to inhibit chemokine-induced leukocyte chemotaxis in vitro. These studies examined the role of Slit2 in modulating inflammation in vivo. In a rat model of glomerulonephritis, endogenous glomerular Slit2 expression fell after disease induction, and its inhibition during the early disease period accelerated inflammation. Ex vivo glomerular leukocytes showed decreased chemokine and chemoattractant-induced chemotaxis in response to Slit2, suggesting an anti-inflammatory role for glomerular Slit2. In contrast to the effect of inhibition, glomerulonephritis was ameliorated by systemic Slit2 administration. Slit2 treatment improved disease histologically and also improved renal function when given early in the disease course. Leukocytes harvested from rats receiving Slit2 showed decreased monocyte chemoattractant protein-1 (MCP)-1-mediated migration, consistent with a peripheral Slit2 effect. In keeping with this functional alteration, Slit2-mediated inhibition of RAW264.7 cell chemotaxis was associated with decreased levels of active cdc42 and Rac1, implicating GTPases in leukocyte Slit2 signaling. These findings suggest a role for endogenous Slit2 in the inhibition of chemoattractant-mediated signals, demonstrate a potentially important anti-inflammatory effect for Slit2 in vivo, and provide further evidence for conserved mechanisms guiding the process of migration in distinct cell types.
American Journal Of Pathology 08/2004; 165(1):341-52. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Interleukin-18 (IL-18), a potent inducer of interferon gamma (IFN-gamma) production, is a cytokine involved in the cell-mediated immune response that is expressed during inflammatory and pathologic conditions. IFN-gamma plays a role in the development of some models of glomerulonephritis (GN); however, the role of IL-18 in the production of IFN-gamma during these pathologies has not been studied.
Rat IL-18 cDNA was isolated and the regulation of IL-18 gene expression was studied. IFN-gamma and IL-18 expression were determined in anti-glomerular basement membrane (GBM) antibody (Ab)-induced GN. Recombinant active IL-18 (rIL-18) was used to further identify its effect on IFN-gamma production during this GN. Glomerular injury and levels of IFN-gamma were assayed in Wistar Kyoto (WKY) rats with anti-GBM GN in the presence or absence of rIL-18.
Rat IL-18, similar to the mouse clone, requires processing by the IL-1beta converting enzyme to become activated. A rat IL-18 5'-untranslated region (UTR) translational inhibitor was identified that strongly inhibited the synthesis of IL-18. This translational inhibitor with different lengths (180 and 130 bp) was highly expressed during GN and correlated with minimal IFN-gamma mRNA expression. Injection of recombinant active IL-18 in WKY rats with anti-GBM GN was associated with an increase of glomerular IFN-gamma levels, proliferating cell nuclear antigen (PCNA)-ED1+ cells, and PCNA-CD8+ cells, with worsening of glomerular injury.
These data suggest that the translational control of IL-18 expression by its 5'-UTR limits the production of IL-18, resulting in restricted expression of mRNA and protein IFN-gamma in this model of GN. Furthermore, it was suggested that possible IL-18/IFN-gamma induction of local proliferation of macrophages and CD8+ cells might be an important mechanism for amplifying CD8+-mediated macrophage-dependent GN.
Kidney International 08/2003; 64(1):160-9. · 8.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Glomerular monocyte/macrophage (Mo/M phi) infiltrates play a role in many forms of glomerulonephritis (GN), and the intensity of Mo/M phi trafficking correlates with the loss of renal function and histological damage. We analyzed the functional role of macrophage-derived chemokine (MDC), a potent mononuclear cell chemoattractant, during the progression of anti-glomerular basement membrane (GBM) antibody (Ab) GN, a model of crescentic GN in the WKY rat, and whether the effects of MDC were dependent on its receptor CCR4. MDC mRNA and protein expression were markedly induced in nephritic glomeruli throughout the disease. Blocking the function of MDC did not affect the developing of the disease from days 2 to 7, but it dramatically blocked M omicron/M phi infiltration in the glomeruli, prevented crescent formation, and reversed renal function impairment during days 7 to 14 of the anti-GBM GN. In this study, we also found that MDC activity on M omicron/M phi in this GN was at least partly dependent on a new variant of CCR4. These results suggest that MDC is critically involved in the development of anti-GBM GN from acute glomerular injury to irreversible tissue damage. In addition, an antagonist to MDC may represent a prime drug target for therapeutic application to intervene in the progression of anti-GBM GN and in other M omicron/M phi-dominant GN.
American Journal Of Pathology 05/2003; 162(4):1061-73. · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Prevention of crescentic glomerulonephritis by immunoneutralization of the fractalkine receptor CX3CR1.Background
Fractalkine is a newly identified T-cell and monocyte/macrophage (Mφ) chemokine with a transmembrane domain and is a cell-surface protein on activated endothelium. It can mediate adhesion of cells expressing the fractalkine receptor CX3CR1. These unique features make fractalkine well suited for leukocyte recruitment in tissues with high blood flow as in the renal glomerulus.Methods
Fractalkine expression in glomeruli and response of isolated glomerular inflammatory cells to fractalkine were studied in the Wistar-Kyoto (WKY) crescentic glomerulonephritis model. Antibody was used to confirm the proinflammatory role of fractalkine.ResultsFractalkine was markedly induced in the endothelium of nephritic rat glomeruli, and inflammatory leukocytes infiltrating the glomeruli expressed increased levels of CX3CR1. Anti-CX3CR1 antibody treatment dramatically blocked leukocyte infiltration in the glomeruli, prevented crescent formation, and improved renal function.Conclusions
Fractalkine plays a central role in leukocyte trafficking at the endothelium in the high-flow glomerular circuit and, in turn, implicates CX3CR1 as a prime drug target for therapeutic intervention of endothelium-related inflammatory diseases.
Kidney International 08/1999; 56(2):612-620. · 8.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemokines play a central role in immune and inflammatory responses. It has been observed
recently that certain viruses have evolved molecular piracy and mimicry mechanisms by encoding and synthesizing proteins that
interfere with the normal host defense response. One such
viral protein, vMIP-II, encoded by human herpesvirus 8, has been identified with in vitro antagonistic activities against
CC and CXC chemokine receptors. We report here that vMIP-II
has additional antagonistic activity against CX3CR1, the receptor for fractalkine. To investigate
the potential therapeutic effect of this broad-spectrum chemokine antagonist, we studied the antiinflammatory activity of
vMIP-II in a rat model of experimental glomerulonephritis induced by
an antiglomerular basement membrane antibody. vMIP-II potently inhibited monocyte
chemoattractant protein 1–, macrophage inflammatory protein 1β–, RANTES (regulated on activation, normal T cell expressed
and secreted)-, and fractalkine-induced chemotaxis of activated
leukocytes isolated from nephritic glomeruli, significantly reduced leukocyte infiltration to the
glomeruli, and markedly attenuated proteinuria. These results suggest that molecules encoded by
some viruses may serve as useful templates for the development of antiinflammatory compounds.
Journal of Experimental Medicine 06/1998; 188(1):193-198. · 13.91 Impact Factor