Induction of β-family chemokines mRNA in human embryonic astrocytes by inflammatory cytokines

The cellular infiltration found during CNS inflammation consists of monocytes and activated T cells, suggesting the presence of cell-specific chemotactic signals during inflammatory responses. Astrocyte chemokine expression might contribute to site-specific leukocyte infiltration within the CNS. To investigate the factors that regulate astrocyte chemokine expression, we examined the ability of human fetal astrocytes to induce β-family chemokine mRNA. Astrocyte-derived monocyte chemoattractant protein-1 (MCP-1), RANTES, macrophage inflammatory protein-1α (MIP-1α), and MIP-1β mRNA were easily induced by lipopolysaccharide and/or the proinflammatory cytokines (IFNγ and/or TNF-α), respectively. Addition of both IFNγ and TNF-α together did not lead to an additive effect but resulted in the inhibition of MCP-1 and MIP-1β mRNA expression, indicating that interaction between chemokines and cytokines may play a key role in regulating the local immune response of resident and infiltrating cells at the site of lesion. Interestingly, ultraviolet light-inactivated measles virus, but not cytomegalovirus, strongly induced expression of MCP-1, RANTES, MIP-1α, and MIP-1β mRNA in human embryonic astrocytes, especially MCP-1 and MIP-1β. An association occurs between the β-family chemokine expression in astrocytes and inflammatory factors/virus, suggesting a possible role for β-family chemokines in the pathogenesis of CNS inflammatory disease.     

Chemokines and their receptors in the brain: pathophysiological roles in ischemic brain injury

Chemokines constitute a large family of structurally-related small cytokines originally identified as factors regulating the migration of leukocytes in inflammatory and immune responses. Production of chemokines and their receptors in the brain has been reported under various pathological conditions. We revealed that mRNA expression for monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha), members of the CC chemokines, was induced in the rat brain after focal cerebral ischemia, and that intracerebroventricular injection of viral macrophage inflammatory protein-II (vMIP-II), a broad-spectrum chemokine receptor antagonist, reduced infarct volume in a dose-dependent manner. These findings suggest that brain chemokines are involved in ischemic injury, and that chemokine receptors are potential targets for therapeutic intervention in stroke. Another potential target to suppress the harmful effect of chemokines is the signal transmission system(s) regulating the chemokine production. However, very little is known about how the production of chemokines is regulated in the ischemic brain. We examined the induction of MCP-1 production by excitotoxic injury via activation of NMDA receptors in the cortico-striatal slice cultures, and found that excitotoxic injury induced MCP-1 production in the slice culture. Almost all of the MCP-1 immunoreactivity was located on astrocytes. On the other hand, NMDA-treatment failed to increase the MCP-1 production in the enriched astrocyte cultures, indicating that NMDA dose not directly act on astrocytes. Some signal(s) is likely sent from the injured neurons to astrocytes to induce the MCP-1 production. These results showed that organotypic slice cultures are useful to investigate the molecular mechanism regulating the chemokine production in the injured brain.     

Monocyte chemotactic protein-1 regulates leukocyte recruitment during gastric ulcer recurrence induced by tumor necrosis factor-alpha

TNF-alpha has numerous biological activities, including the induction of chemokine expression, and is involved in many gastric injuries. C-C chemokines [monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha] and C-X-C chemokines [MIP-2 and cytokine-induced neutrophil chemoattractant (CINC)-2alpha] mediate chemotaxis of monocytes and neutrophils, respectively. We examined the roles of TNF-alpha and dynamics of chemokine expression in gastric ulceration including ulcer recurrence and indomethacin-induced injury. Rats with healed chronic gastric ulcers received intraperitoneal TNF-alpha to induce ulcer recurrence. Some rats were given neutralizing antibodies against neutrophils or MCP-1 together with TNF-alpha. In a separate experiment, rats were orally administered 20 mg/kg indomethacin with or without pretreatment with pentoxifylline (an inhibitor of TNF-alpha synthesis) or anti-MCP-1 antibody. TNF-alpha (1 microg/kg) induced gastric ulcer recurrence after 48 h, which was completely prevented by anti-neutrophil antibody. TNF-alpha increased the number of macrophages and MCP-1 mRNA expression in scarred mucosa from 4 h, whereas it increased MPO activities (marker of neutrophil infiltration) and mRNA expression of MIP-2 and CINC-2alpha from 24 h. Anti-MCP-1 antibody inhibited leukocyte infiltration with reduction of the levels of C-X-C chemokines and prevented ulcer recurrence. Indomethacin treatment increased TNF-alpha/chemokine mRNA expression from 30 min and induced macroscopic erosions after 4 h. Pentoxifylline inhibited the indomethacin-induced gastric injury with reduction of neutrophil infiltration and expression of chemokine (MCP-1, MIP-2, and CINC-2alpha). Anti-MCP-1 antibody also inhibited the injury and these inflammatory responses but did not affect TNF-alpha mRNA expression. In conclusion, increased MCP-1 triggered by TNF-alpha may play a key role in gastric ulceration by regulating leukocyte recruitment and chemokine expression.     

Regulated production and molecular diversity of human liver and activation-regulated chemokine/macrophage inflammatory protein-3 alpha from normal and transformed cells

Liver and activation-regulated chemokine (LARC), also designated macrophage inflammatory protein-3alpha (MIP-3alpha), Exodus, or CCL20, is a C-C chemokine that attracts immature dendritic cells and memory T lymphocytes, both expressing CCR6. Depending on the cell type, this chemokine was found to be inducible by cytokines (IL-1beta) and by bacterial, viral, or plant products (including LPS, dsRNA, and PMA) as measured by a specific ELISA. Although coinduced with monocyte chemotactic protein-1 (MCP-1) and IL-8 by dsRNA, measles virus, and IL-1beta in diploid fibroblasts, leukocytes produced LARC/MIP-3alpha only in response to LPS. However, in myelomonocytic THP-1 cells LARC/MIP-3alpha was better induced by phorbol ester, whereas in HEp-2 epidermal carcinoma cells IL-1beta was the superior inducer. The production levels of LARC/MIP-3alpha (1-10 ng/ml) were, on the average, 10- to 100-fold lower than those of IL-8 and MCP-1, but were comparable to those of other less abundantly secreted chemokines. Natural LARC/MIP-3alpha protein isolated from stimulated leukocytes or tumor cell lines showed molecular diversity, in that NH(2)- and COOH-terminally truncated forms were purified and identified by amino acid sequence analysis and mass spectrometry. In contrast to other chemokines, including MCP-1 and IL-8, the natural processing did not affect the calcium-mobilizing capacity of LARC/MIP-3alpha through its receptor CCR6. Furthermore, truncated natural LARC/MIP-3alpha isoforms were equally chemotactic for lymphocytes as intact rLARC/MIP-3alpha. It is concluded that in addition to its role in homeostatic trafficking of leukocytes, LARC/MIP-3alpha can function as an inflammatory chemokine during host defense.     

Substance P treatment stimulates chemokine synthesis in pancreatic acinar cells via the activation of NF-kappaB

Acinar cell injury early in acute pancreatitis leads to a local inflammatory reaction and to the subsequent systemic inflammatory response, which may result in multiple organ dysfunction and death. Inflammatory mediators, including chemokines and substance P (SP), are known to play a crucial role in the pathogenesis of acute pancreatitis. It has been shown that pancreatic acinar cells produce the chemokine monocyte chemoattractant protein-1 (MCP-1) in response to caerulein hyperstimulation, demonstrating that acinar-derived MCP-1 is an early mediator of inflammation in acute pancreatitis. Similarly, SP levels in the pancreas and pancreatic acinar cell expression of neurokinin-1 receptor, the primary receptor for SP, are both increased during secretagogue-induced experimental pancreatitis. This study aims to examine the functional consequences of exposing mouse pancreatic acinar cells to SP and to determine whether it leads to proinflammatory signaling, such as production of chemokines. Exposure of mouse pancreatic acini to SP significantly increased synthesis of MCP-1, macrophage inflammatory protein-1alpha (MIP-1alpha), as well as MIP-2. Furthermore, SP also increased NF-kappaB activation. The stimulatory effect of SP was specific to chemokine synthesis through the NF-kappaB pathway, since the increase in chemokine production was completely attenuated when pancreatic acini were pretreated with the selective NF-kappaB inhibitor NF-kappaB essential modulator-binding domain peptide. This study shows that SP-induced chemokine synthesis in mouse pancreatic acinar cells is NF-kappaB dependent.     

Interleukin-1beta stimulates macrophage inflammatory protein-1alpha and -1beta expression in human neuronal cells (NT2-N)

Chemokines are important mediators in immune responses and inflammatory processes of neuroimmunologic and infectious diseases. Although chemokines are expressed predominantly by cells of the immune system, neurons also express chemokines and chemokine receptors. We report herein that human neuronal cells (NT2-N) produce macrophage inflammatory protein-1alpha and -1beta (MIP-1alpha and MIP-1beta), which could be enhanced by interleukin (IL)-1beta at both mRNA and protein levels. The addition of supernatants from human peripheral blood monocyte-derived macrophage (MDM) cultures induced MIP-1beta mRNA expression in NT2-N cells. Anti-IL-1beta antibody removed most, but not all, of the MDM culture supernatant-induced MIP-1beta mRNA expression in NT2-N cells, suggesting that IL-1beta in the MDM culture supernatants is a major factor in the induction of MIP-1beta expression. Investigation of the mechanism(s) responsible for IL-1beta-induced MIP-1alpha and -1beta expression demonstrated that IL-1beta activated nuclear factor kappa B (NF-kappaB) promoter-directed luciferase activity in NT2-N cells. Caffeic acid phenethyl ester, a potent and specific inhibitor of activation of NF-kappaB, not only blocked IL-1beta-induced activation of the NF-kappaB promoter but also decreased IL-1beta-induced MIP-1alpha and -1beta expression in NT2-N cells. These data suggest that NF-kappaB is at least partially involved in the IL-1beta-mediated action on MIP-1alpha and -1beta in NT2-N cells. IL-1beta-mediated up-regulation of beta-chemokine expression may have important implications in the immunopathogenesis of inflammatory diseases in the CNS.     

The effect of MCP-1 depletion on chemokine and chemokine-related gene expression: evidence for a complex network in acute inflammation

The expression of chemokines has been suggested to involve an interdependent network, with the absence of a single chemokine affecting the expression of multiple other chemokines. Monocyte chemoattractant protein (MCP-1), a member of C-C chemokine superfamily, plays a critical role in the recruitment and activation of leukocytes during acute inflammation. To examine the effect of the loss of MCP-1 on expression of the chemokine network, we compared the mRNA expression profiles of MCP-1(-/-) and wild type mice during the acute inflammatory phase of excisional wounds. Utilizing a mouse cDNA array containing 514 chemokine and chemokine related genes, the loss of MCP-1 was observed to cause a significant upregulation of nine genes (Decorin, Persephin, IL-1beta, MIP-2, MSP, IL1ra, CCR5, CCR3, IL-11) and significant downregulation of two genes (CCR4 and CD3Z) in acute wounds. The array data was confirmed by semi-quantitative RT-PCR. The effect of MCP-1 deletion on chemokine expression was further examined in isolated macrophages. Compared to wild type, LPS-stimulated peritoneal macrophages from MCP-1(-/-) mice showed a significant increase in the expression of RANTES, MIP-1beta, MIP-1alpha and MIP-2 mRNA. The data suggest that loss of a single chemokine perturbs the chemokine network not only in the setting of acute inflammation but even in an isolated inflammatory cell, the macrophage.     

Blockade of neurokinin-1 receptor attenuates CC and CXC chemokine production in experimental acute pancreatitis and associated lung injury

Accumulating evidence suggests the neuropeptide substance P (SP) and its receptor neurokinin-1 receptor (NK-1R) play a pivotal role in the pathogenesis of acute pancreatitis (AP). However, the mechanisms remain unclear. The present study investigated whether chemokines as proinflammatory molecules are involved in SP-NK-1R-related pathogenesis of this condition. We observed temporally and spatially selective chemokine responses in secretagogue caerulein-induced AP in mice. CC chemokines monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein-1alpha (MIP-1alpha) and CXC chemokine MIP-2 were elevated after AP induction. Time-dependent, tissue-specific analysis of their mRNA and protein expression suggested that they are early mediators in the condition and mediate local as well as systemic inflammatory responses. In contrast, another CC chemokine regulated on activation, T cells expressed and secreted (RANTES) was only involved in local pancreatic inflammation at a later stage of the disease. Either prophylactic or therapeutic treatment with a potent selective NK-1R antagonist CP-96,345 significantly suppressed caerulein-induced increase in MCP-1, MIP-1alpha, and MIP-2 expression but had no apparent effect on RANTES expression. The suppression effect of CP-96,345 on MCP-1, MIP-1alpha, and MIP-2 expression was concordantly demonstrated by immunohistochemistry, which, additionally, suggested that chemokine immunoreactivity was localized to acinar cells and the infiltrating leukocytes in the pancreas and alveolar macrophages, epithelial cells, and endothelial cells in the lungs. Our data suggest that SP, probably by acting via NK-1R on various chemokine-secreting cells in the pancreas and lungs, stimulates the release of chemokines that aggravate local AP and the development of its systemic sequelae.     

Regulation of macrophage chemokine expression by lipopolysaccharide in vitro and in vivo.

The host response to Gram-negative LPS is characterized by an influx of inflammatory cells into host tissues, which is mediated, in part, by localized production of chemokines. The expression and function of chemokines in vivo appears to be highly selective, though the molecular mechanisms responsible are not well understood. All CXC (IFN-gamma-inducible protein (IP-10), macrophage inflammatory protein (MIP)-2, and KC) and CC (JE/monocyte chemoattractant protein (MCP)-1, MCP-5, MIP-1alpha, MIP-1beta, and RANTES) chemokine genes evaluated were sensitive to stimulation by LPS in vitro and in vivo. While IL-10 suppressed the expression of all LPS-induced chemokine genes evaluated in vitro, treatment with IFN-gamma selectively induced IP-10 and MCP-5 mRNAs, but inhibited LPS-induced MIP-2, KC, JE/MCP-1, MIP-1alpha, and MIP-1beta mRNA and/or protein. Like the response to IFN-gamma, LPS-mediated induction of IP-10 and MCP-5 was Stat1 dependent. Interestingly, only the IFN-gamma-mediated suppression of LPS-induced KC gene expression was IFN regulatory factor-2 dependent. Treatment of mice with LPS in vivo also induced high levels of chemokine mRNA in the liver and lung, with a concomitant increase in circulating protein. Hepatic expression of MIP-1alpha, MIP-1beta, RANTES, and MCP-5 mRNAs were dramatically reduced in Kupffer cell-depleted mice, while IP-10, KC, MIP-2, and MCP-1 were unaffected or enhanced. These findings indicate that selective regulation of chemokine expression in vivo may result from differential response of macrophages to pro- and antiinflammatory stimuli and to cell type-specific patterns of stimulus sensitivity. Moreover, the data suggest that individual chemokine genes are differentially regulated in response to LPS, suggesting unique roles during the sepsis cascade.     

Visualization of chemokine binding sites on human brain microvessels

The chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) aid in directing leukocytes to specific locales within the brain and spinal cord during central nervous system inflammation. However, it remains unclear how these chemokines exert their actions across a vascular barrier, raising speculation that interaction with endothelial cells might be required. Therefore, experiments were performed to determine whether binding domains for these chemokines exist along the outer surface of brain microvessels, a feature that could potentially relay chemokine signals from brain to blood. Using a biotinylated chemokine binding assay with confocal microscopy and three-dimensional image reconstruction, spatially resolved binding sites for MCP-1 and MIP-alpha around human brain microvessels were revealed for the first time. Binding of labeled MCP-1 and MIP-1alpha could be inhibited by unlabeled homologous but not heterologous chemokine, and was independent of the presence of heparan sulfate, laminin, or collagen in the subendothelial matrix. This is the first evidence of specific and separate binding domains for MCP-1 and MIP-1alpha on the parenchymal surface of microvessels, and highlights the prospect that specific interactions of chemokines with microvascular elements influence the extent and course of central nervous system inflammation.     

Distinct temporal patterns of macrophage-inflammatory protein-2 and KC chemokine gene expression in surgical injury

In the present study the regulation of CXC chemokine expression was evaluated in full-thickness abdominal wounds in mice. During the first 24 h after injury, IL-1alphabeta, KC, macrophage-inflammatory protein (MIP)-2, and monocyte chemoattractant protein-1 were the predominant cytokines and chemokines produced; TNF-alpha was not detected. Chemokine mRNA expression and protein secretion occurred in two temporal stages. The first, which reached a maximum at 6 h, was associated with high levels of IL-1alpha and KC and low levels of MIP-2. This stage could be reproduced by intradermal injection of IL-1alpha or IL-1beta and was partially blocked by injection of neutralizing Ab against IL-1alpha but not IL-1beta. In animals depleted of circulating neutrophils, chemokine expression was reduced by nearly 70% during this stage. In the second stage, which peaked at 24 h after injury, modest but significant levels of IL-1beta were detected in association with low levels of KC and high levels of MIP-2. This pattern of chemokine expression could not be mimicked by injection of IL-1alpha or IL-1beta (even with prolonged exposure), although MIP-2 expression could be partially inhibited by intradermal injection of neutralizing Ab against IL-1beta. Surprisingly, neutrophil depletion before injury resulted in sustained high levels of both KC and MIP-2 expression. These observations demonstrate that these two closely related chemokines are under distinct regulatory controls in vivo that are likely to reflect the temporally ordered participation of different cell types and/or extracellular stimuli and inhibitors.     

Characterization of binding sites for chemokines MCP-1 and MIP-1alpha on human brain microvessels

The presence of binding sites for the beta chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) has recently been identified on human brain microvessels. We extend these findings in this report to reveal that such sites exemplify characteristics of the recognized major receptors for MCP-1 and MIP-1alpha: CCR2, and CCR1 and CCR5, respectively. Specifically, labeled MCP-1 binding to isolated brain microvessels was inhibited by unlabeled MCP-1 and MCP-3, the latter another CCR2 ligand, but not by MIP-1alpha. Inhibition of labeled MIP-1alpha binding was achieved with unlabeled MIP-1alpha and RANTES, the latter a beta chemokine that binds to both CCR1 and CCR5, but not by MCP-1. Labeled MIP-1alpha binding was also antagonized by unlabeled MCP-3, which is also recognized by CCR1, and MIP-1beta, which is a ligand for CCR5. Labeled MCP-1 and MIP-1alpha were further observed to be internalized within the endothelial cells of brain microvessels, following their binding to the microvascular surface at 37 degrees C. Additionally, exposure of microvessels to unlabeled MCP-1 or MIP-1alpha was accompanied by the initial loss and subsequent recovery of surface binding sites for these chemokines, which occurred on a time scale consistent with ligand-induced endocytosis and recycling. These collective features bear striking similarity to those that characterize interactions of MCP-1 and MIP-1alpha with their receptors on leukocytes and underscore the concept of cognate chemokine receptors on brain microvascular endothelium.     

Role of CC chemokines (macrophage inflammatory protein-1 beta, monocyte chemoattractant protein-1, RANTES) in acute lung injury in rats

The role of the CC chemokines, macrophage inflammatory protein-1 beta (MIP-1 beta), monocyte chemotactic peptide-1 (MCP-1), and RANTES, in acute lung inflammatory injury induced by intrapulmonary deposition of IgG immune complexes injury in rats was determined. Rat MIP-1 beta, MCP-1, and RANTES were cloned, the proteins were expressed, and neutralizing Abs were developed. mRNA and protein expression for MIP-1 beta and MCP-1 were up-regulated during the inflammatory response, while mRNA and protein expression for RANTES were constitutive and unchanged during the inflammatory response. Treatment of rats with anti-MIP-1 beta Ab significantly decreased vascular permeability by 37% (p = 0.012), reduced neutrophil recruitment into lung by 65% (p = 0.047), and suppressed levels of TNF-alpha in bronchoalveolar lavage fluids by 61% (p = 0.008). Treatment of rats with anti-rat MCP-1 or anti-rat RANTES had no effect on the development of lung injury. In animals pretreated intratracheally with blocking Abs to MCP-1, RANTES, or MIP-1 beta, significant reductions in the bronchoalveolar lavage content of these chemokines occurred, suggesting that these Abs had reached their targets. Conversely, exogenously MIP-1 beta, but not RANTES or MCP-1, caused enhancement of the lung vascular leak. These data indicate that MIP-1 beta, but not MCP-1 or RANTES, plays an important role in intrapulmonary recruitment of neutrophils and development of lung injury in the model employed. The findings suggest that in chemokine-dependent inflammatory responses in lung CC chemokines do not necessarily demonstrate redundant function.     

Differential regulation of C-C chemokines during fibroblast-monocyte interactions: adhesion vs. inflammatory cytokine pathways.

The cell-to-cell interactions during chronic inflammatory diseases likely contribute to leukocyte accumulation leading to increased pathology and organ dysfunction. In particular, there is a paucity of information relating to the maintenance of chronic fibrotic diseases. Using a lung fibroblast line and enriched monocyte populations, we have investigated the activational events which contribute to the production of two C-C chemokines, macrophage inflammatory protein-1 alpha (MIP-1alpha) and monocyte chemoattractant protein-1 (MCP-1), during fibroblast-monocyte interactions. Neither the fibroblast cell line (16lu) nor isolated monocytes alone produced significant levels of MIP-1alpha or MCP-1. However, when isolated monocytes were layered onto 16 lu fibroblast monolayers a significant increase in MIP-1alpha and MCP-1 production was observed. The use of fixed cell populations indicated that the MIP-1alpha was derived from monocytes and MCP-1 from both cell populations. To examine the molecules which were required for chemokine production during the interaction, specific antibodies were used in the co-cultures. Blocking beta3-integrin interactions significantly inhibited MIP-1alpha production. In contrast, beta-integrin interactions had no effect on the MCP-1 production, while, neutralization of TNF significantly decreased MCP-1 production during the co-culture. These data indicate that fibroblast-monocyte interactions induce chemokine production through different mechanisms and a combination of these responses may contribute to the maintenance of the mononuclear cell accumulation during disease progression.     

Structural Insights into the Interaction between a Potent Anti-inflammatory Protein,Viral CC Chemokine Inhibitor (vCCI), and the Human CC Chemokine,Eotaxin-1

Chemokines play important roles in the immune system, not only recruiting leukocytes to the site of infection and inflammation but also guiding cell homing and cell development. The soluble poxvirus-encoded protein viral CC chemokine inhibitor (vCCI), a CC chemokine inhibitor, can bind to human CC chemokines tightly to impair the host immune defense. This protein has no known homologs in eukaryotes and may represent a potent method to stop inflammation. Previously, our structure of the vCCI·MIP-1β (macrophage inflammatory protein-1β) complex indicated that vCCI uses negatively charged residues in β-sheet II to interact with positively charged residues in the MIP-1β N terminus, 20s region and 40s loop. However, the interactions between vCCI and other CC chemokines have not yet been fully explored. Here, we used NMR and fluorescence anisotropy to study the interaction between vCCI and eotaxin-1 (CCL11), a CC chemokine that is an important factor in the asthma response. NMR results reveal that the binding pattern is very similar to the vCCI·MIP-1β complex and suggest that electrostatic interactions provide a major contribution to binding. Fluorescence anisotropy results on variants of eotaxin-1 further confirm the critical roles of the charged residues in eotaxin-1. In addition, the binding affinity between vCCI and other wild type CC chemokines, MCP-1 (monocyte chemoattractant protein-1), MIP-1β, and RANTES (regulated on activation normal T cell expressed and secreted), were determined as 1.1, 1.2, and 0.22 nm, respectively. To our knowledge, this is the first work quantitatively measuring the binding affinity between vCCI and multiple CC chemokines.     

Specific induction of macrophage inflammatory protein 1-alpha in glial cells of Sandhoff disease model mice associated with accumulation of N-acetylhexosaminyl glycoconjugates

Sandhoff disease is a lysosomal storage disease caused by simultaneous deficiencies of beta-hexosaminidase A (HexA; alphabeta) and B (HexB; betabeta), due to a primary defect of the beta-subunit gene (HEXB) associated with excessive accumulation of GM2 ganglioside (GM2) and oligosaccharides with N-acetylhexosamine residues at their non-reducing termini, and with neurosomatic manifestations. To elucidate the neuroinflammatory mechanisms involved in its pathogenesis, we analyzed the expression of chemokines in Sandhoff disease model mice (SD mice) produced by disruption of the murine Hex beta-subunit gene allele (Hexb-/-). We demonstrated that chemokine macrophage inflammatory protein-1 alpha (MIP-1alpha) was induced in brain regions, including the cerebral cortex, brain stem and cerebellum, of SD mice from an early stage of the pathogenesis but not in other systemic organs. On the other hand, little changes in other chemokine mRNAs, including those of RANTES (regulated upon activation, normal T expressed and secreted), MCP-1 (monocyte chemotactic protein-1), SLC (secondary lymphoid-tissue chemokine), fractalkine and SDF-1 (stromal derived factor-1), were detected. Significant up-regulation of MIP-1alpha mRNA and protein in the above-mentioned brain regions was observed in parallel with the accumulation of natural substrates of HexA and HexB. Immunohistochemical analysis revealed that MIP-1alpha-immunoreactivity (IR) in the above-mentioned brain regions of SD mice was co-localized in Iba1-IR-positive microglial cells and partly in glial fibrillary acidic protein (GFAP)-IR-positive astrocytes, in which marked accumulation of N-acetylglucosaminyl (GlcNAc)-oligosaccharides was observed from the presymptomatic stage of the disease. In contrast, little MIP-1alpha-IR was observed in neurons in which GM2 accumulated predominantly. These results suggest that specific induction of MIP-1alpha might coincide with the accumulation of GlcNAc-oligosaccharides due to a HexB deficiency in resident microglia and astrocytes in the brains of SD mice causing their activation and acceleration of the progressive neurodegeneration in SD mice.     

A small synthetic molecule capable of preferentially inhibiting the production of the CC chemokine monocyte chemotactic protein-1.

Blocking chemokine production or action is a major target for pharmacological intervention in different human diseases. Bindarit (2-methyl-2-[[1-(phenylmethyl)-1H-indazol-3yl]methoxy]propan oic acid) dose-dependently inhibited MCP-1 and TNF-alpha production induced in vitro in monocytes by LPS and Candida albicans. It did not affect the production of the cytokines IL-1, IL-6, or the chemokines IL-8, MIP-1alpha and RANTES. In the air pouch model in mice, oral treatment reduced monocyte recruitment and local MCP-1 production, induced by carrageenan or IL-1 injection. In NZB/W mice, a model of lupus nephritis, oral treatment prolonged survival and delayed the onset of proteinuria. The results presented here show that bindarit is a preferential inhibitor of the production of MCP-1 in vitro and in vivo and suggest that its beneficial effects in models of joint and kidney inflammation are related to its anti-MCP-1 action. It is therefore possible to selectively and differentially regulate chemokines by targeting their production with small synthetic molecules.