The improvement of nonalcoholic steatohepatitis by Poria cocos polysaccharides associated with gut microbiota and NF-κB/CCL3/CCR1 axis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) has been linked to inflammation induced by intestinal microbiota. Poria cocos polysaccharides (PCP) possesses anti-inflammation and immunomodulation functions; however, its preventive effects against NASH and potential mechanisms need to be explored.

METHODS

The composition of PCP was determined using ion chromatography. C57BL/6 mice were administered the methionine and choline deficient (MCD) diet for 4 weeks to establish the NASH model or methionine-choline-sufficient (MCS) diet to serve as the control. Mice were assigned to the MCS group, MCD group, low-dose PCP (LP) group, and high-dose PCP (HP) group, and were administered the corresponding medications via gavage. Serum biochemical index analysis and liver histopathology examination were performed to verify the successful establishment of NASH model and to evaluate the efficacy of PCP. The composition of intestinal bacteria was profiled through 16S rRNA gene sequencing. Hepatic RNA sequencing (RNA-Seq) was performed to explore the potential mechanisms, which were further confirmed using qPCR, western blot, and immunohistochemistry.

RESULTS

PCP consists of glucose, galactose, mannose, D-glucosamine hydrochloride, xylose, arabinose, and fucose. PCP could significantly alleviate symptoms of NASH, including histological liver damage, impaired hepatic function, and increased oxidative stress. Meanwhile, HP could reshape the composition of intestinal bacteria by significantly increasing the relative abundance of Faecalibaculum and decreasing the level of endotoxin load derived from gut bacteria. PCP could also downregulate the expression of pathways associated with immunity and inflammation, including the chemokine signaling pathway, Toll-like receptor signaling pathway, and NF-kappa B signaling pathway. The expression levels of CCL3 and CCR1 (involved in the chemokine signaling pathway), Tlr4, Cd11b, and NF-κb (involved in the NF-kappa B signaling pathway), and Tnf-α (involved in the TNF signaling pathway) were significantly reduced in the HP group compared to the MCD group.

CONCLUSIONS

PCP could prevent the development of NASH, which may be associated with the modulation of intestinal microbiota and the downregulation of the NF-κB/CCL3/CCR1 axis.

CCR1 antagonist J-113863 corrects the imbalance of pro- and anti-inflammatory cytokines in a SJL/J mouse model of relapsing-remitting multiple sclerosis

Multiple sclerosis (MS), an immune-mediated and neurodegenerative disorder of the central nervous system (CNS), is characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model used to study MS. To explore the impact of chemokine receptor CCR1 blockade in EAE and the underlying mechanisms, we used CCR1 antagonist J-113863 in PLP_139-151-induced EAE in SJL/J mice. Following EAE induction, mice were treated with J-113863 (10 mg/kg) daily from day 14 until day 25. We investigated the effect of J-113863 on expression levels of GM-CSF, IL-6, IL-10, IL-27 in CD4⁺ spleen cells, using flow cytometry. We also analyzed the effect of J-113863 on GM-CSF, IL-6, IL-10, IL-27 mRNA and protein expression levels using RT-PCR and Western blot analysis in brain tissues. J-113863 treatment decreased the populations of CD4⁺GM-CSF⁺ and CD4⁺IL-6⁺ cells and increased CD4⁺IL-27⁺ and CD4⁺IL-10⁺ cells in the spleen. J-113863 had a suppressive effect on the mRNA and protein expression levels of GM-CSF, and IL-6 in the brain tissue. On the other hand, J-113863 treatment increased the mRNA and protein expression of IL-10 and IL-27 in the brain tissue. Our results highlighted J-113863's potential role in suppressing pro-inflammatory expression and up-regulating anti-inflammatory mediators, which could represent a beneficial alternative approach to MS treatment.

Targeting Chemokine Receptor CCR1 as a Potential Therapeutic Approach for Multiple Myeloma

Multiple myeloma is an incurable plasma B-cell malignancy with 5-year survival rates approximately 10-30% lower than other hematologic cancers. Treatment options include combination chemotherapy followed by autologous stem cell transplantation. However, not all patients are eligible for autologous stem cell transplantation, and current pharmacological agents are limited in their ability to reduce tumor burden and extend multiple myeloma remission times. The "chemokine network" is comprised of chemokines and their cognate receptors, and is a critical component of the normal bone microenvironment as well as the tumor microenvironment of multiple myeloma. Antagonists targeting chemokine-receptor 1 (CCR1) may provide a novel approach for treating multiple myeloma. In vitro CCR1 antagonists display a high degree of specificity, and in some cases signaling bias. In vivo studies have shown they can reduce tumor burden, minimize osteolytic bone damage, deter metastasis, and limit disease progression in multiple myeloma models. While multiple CCR1 antagonists have entered the drug pipeline, none have entered clinical trials for treatment of multiple myeloma. This review will discuss whether current CCR1 antagonists are a viable treatment option for multiple myeloma, and studies aimed at identifying which CCR1 antagonist(s) are most appropriate for this disease.

Small molecule antagonist of C-C chemokine receptor 1 (CCR1) reduces disc inflammation in the rabbit model

BACKGROUND CONTEXT

Targeting chemokines or chemokine receptors is a promising treatment strategy for diseases with chronic inflammation such as rheumatoid arthritis and discogenic pain. Identifying specific molecules and determining their effectiveness in animal models are the first steps in developing these treatments. Macrophage markers have been detected in the intervertebral disc tissues of patients with disc degenerative disease and discogenic pain and in different animal models. Macrophage recruitment into the disc may play a role in initiation of inflammation and if unresolved may lead to chronic inflammation and subsequent back pain.

PURPOSE

The objectives of these studies are to (1) identify chemokine receptor antagonists that can block macrophage migration induced by disc cells in vitro and (2) determine if intradiscal treatment with these antagonists can reduce disc inflammation and degeneration in vivo.

STUDY DESIGN

In vitro migration assays were used to test effectiveness of chemokine receptor antagonists to block macrophage migration induced by disc cells. The rabbit annular puncture model was used to test for anti-inflammatory and regenerative effects of chemokine receptor antagonist treatment in vivo.

METHODS

In vitro - THP-1 human monocytic cell line and freshly isolated rabbit primary splenocytes were assayed for migration using 3 µm Corning Transwell inserts with conditioned media of interleukin (IL)-1β treated human or rabbit disc cells. Inhibition of macrophage migration was evaluated using different concentrations of small molecule antagonists of C-C chemokine receptor (CCR)1 and CCR2. In vivo - New Zealand White rabbits (n=40) underwent disc puncture and intradiscal treatment with saline, CCR1 or CCR2 antagonists within the same procedure. X-ray and magnetic resonance (MR) images and serum samples were taken for disc height, MRI grade and IL-8 serum level analyses. Intervertebral discs were isolated for RNA analysis of inflammatory and disc phenotypic markers and for immunohistochemical analysis of macrophage marker, RAM11. The outcome measures were compared between the three treatment groups. These studies were funded by a research grant from AO Foundation, Switzerland (Project no S-14-86A; 120000 CHF). CCR1 and CCR2 antagonists were kindly provided by ChemoCentryx (Mountain View, CA).

RESULTS

In vitro migration assays showed that THP-1 migration induced by disc cells was blocked by CCR2 antagonist more effectively than CCR1 antagonist, while rabbit splenocyte migration was inhibited by CCR1 antagonist and not the other. In the rabbit annular puncture model, rabbit discs treated with CCR1 antagonist had significantly better MRI grades than those treated with CCR2 antagonist at 6 weeks post-treatment. Gene expression studies demonstrate that discs treated with CCR1 or CCR2 antagonists expressed less inflammatory markers than saline-treated discs at 3 weeks post-treatment. Although CCR2 antagonist treatment did not reduce inflammatory marker expression at 6 weeks, discs treated with CCR1 antagonist expressed less inflammatory markers and also a higher ratio of collagen type 2 to collagen type 1 genes indicating favorable disc matrix production. There were no significant differences between all three treatment groups in regards to disc height indexes, IL-8 serum levels or macrophage marker detection.

CONCLUSIONS

These studies have identified that small molecule antagonists against CCR2 and CCR1 were respectively effective in blocking THP-1 and rabbit splenocyte migration induced by disc cells in vitro. Further, both CCR2 and CCR1 antagonist intradiscal treatments were effective in reducing disc inflammation at an early time point of 3 weeks. Lastly, only CCR1 antagonist demonstrated anti-inflammatory effects and better MRI grades at 6 weeks.

CLINICAL SIGNIFICANCE

Our preclinical studies demonstrate that CCR1 and CCR2 antagonist delivery through intradiscal injection is sufficient to reduce disc inflammation at early time points, whereas CCR1 antagonists had longer term anti-inflammatory effects. Clinical studies have found that CCR1 antagonist was safe, tolerable and clinically active in reducing inflammation in rheumatoid arthritis patients. These studies suggest that CCR1 antagonist may be a promising biological treatment to reduce disc inflammation that translates to back pain relief.

[Expression and significance of myeloid-derived suppressor cells-associated chemokine MIP-1γ and its receptor CCR1 in the spleen of hepatoma H22-bearing mice]

Objective To study the expression and significance of myeloid-derived suppressor cell (MDSC)-associated chemokines in the spleen of hepatoma H22-bearing mice. Methods The percentage of splenic MDSCs was examined by flow cytometry. Splenic MDSCs were sorted using flow cytometry and co-cultured with activated splenocytes, and then the level of IFN-γ in the supernatant of co-cultured cells was assayed by ELISA. The murine orthotopic hepatoma model was established. The differential cytokine expression in the spleens of normal and tumor-bearing mice was assayed by protein chip, and splenic MDSC-associated chemokines were verified using ELISA. The chemokine receptors on splenic MDSCs were also detected by flow cytometry. Results The percentage of splenic MDSCs was markedly raised in the tumor-bearing mice, and splenic MDSCs exhibited immune-inhibitory function. Ten up-regulated cytokines and nine down-regulated ones were found out using protein chip. Among the up-regulated cytokines, 5 cytokines were chemokines, namely B lymphocyte chemoattractant (BLC), chemokine (C-X-C motif) ligand 16 (CXCL16), macrophage/monocyte chemotactic protein-5 (MCP-5), macrophage inflammatory protein 1γ (MIP-1γ) and MIP-2. The level of splenic MDSC-associated chemokine MIP-1γ significantly increased in the spleen of tumor-bearing mice, and its receptor CCR1 was also expressed on the cell surface of splenic MDSCs. Conclusion Splenic MDSC-associated chemokine MIP-1γ and its receptor CCR1 were obtained by protein chip, and they might be associated with the accumulation of splenic MDSCs in hepatoma H22-bearing mice.

Abnormal expression of chemokine receptors on T-cells from patients with systemic lupus erythematosus

The expressionof chemokinereceptors on T-cells and chemokinelevels in the blood was studied in 23 patients with SLE (ACR criteria), seven patients with rheumatoid arthritis (RA) and in 15 healthy controls using flow cytometry, RT-PCR and ELISA. The cell surface expression of the chemokine receptors CXCR5 and CCR6 was decreased in SLE patients compared with controls (P 0.051 and P 0.002, respectively). The decrease of CXCR5 was confined to SLE patients with inactive disease (SLEDAI < 6) compared with active disease (SLEDAI ≥6) and controls. CXCR2 and CCR1 were increased in patients with active SLE compared with patients with inactive disease (P 0.001 and P 0.01, respectively) and with controls (P 0.02 and P 0.053, respectively). The levels of the chemokines MIP-1b MCP-1, SDF-1a, IP-10 and RANTES were significantly elevated in SLE patients compared with controls. Patients with renal involvement had increased surface expression of CXCR3 and CCR3 (P 0.04 in both) and a lower level of soluble IP-10 compared with patients without renal disease (P 0.025) and compared with controls (P 0.001). The ratio between CCR5 and CCR3 was significantly increased in RA patients compared with SLE patients and controls supporting a Th1 overweight in RA. In conclusion, patients with SLE showed abnormal T-cell expression of several chemokine receptors and levels of soluble chemokines in their plasma/serum.

Phase I evaluation of the safety, pharmacokinetics and pharmacodynamics of CP-481,715

BACKGROUND AND OBJECTIVES

The chemokine receptor CCR1 is believed to play a role in several inflammatory diseases, primarily by promoting the migration of leukocytes through the endothelial barrier. Thus, a possible strategy for treating inflammatory diseases is inhibition of leukocyte infiltration by antagonising CCR1. Recently, CP-481,715 has been described as a potent and specific antagonist of CCR1. The aims of this study were to assess the safety, pharmacokinetics and pharmacodynamics of CP-481,715 along with drug interactions with ciclosporin.

SUBJECTS AND METHODS

This was a phase I randomised, double-blind, placebo-controlled study with CP-481,715 in 78 healthy male volunteers. Subjects were administered escalating CP-481,715 doses of up to 3000 mg with food and after fasting in the single-dose study. In the drug interaction study, which was a single-dose, two-way crossover study, 12 subjects received a 300 mg dose of CP-481,715 as a suspension of polymorph A under fasted conditions, both with and without prior administration of ciclosporin.

RESULTS AND CONCLUSIONS

All doses of CP-481,715 were well tolerated, with linear pharmacokinetics up to the 300 mg dose. The pharmacodynamic activity of CP-481,715 was detected ex vivo by demonstrating a dose-related and linear increase in the amount of macrophage inflammatory protein-1alpha, CCL3, required to induce CD11b upregulation. Analysis of vital signs indicated no consistent clinical effects, and statistical analysis of ECG characteristics demonstrated no significant prolongation of the corrected QT interval. A drug-drug interaction study with ciclosporin demonstrated that CP-481,715 clearance was decreased by ciclosporin, consistent with its ability to compete with P-glycoprotein. Phase II studies may be warranted to see if CP-481,715 exhibits efficacy in treating inflammatory diseases such as rheumatoid arthritis, multiple sclerosis or transplant rejection.

Mast cells as effector cells: a co-stimulating question

Mast cells are currently recognized as effector cells in many settings beyond just allergic reactions, including innate immunity, autoimmunity, chronic inflammatory disorders and atherosclerosis. Signaling pathways of the mast cell response have been widely explored in the past but these are still linked with single axes, such as the high affinity IgE receptor FcepsilonRI, presumably an exclusive determinant of the magnitude of the response to allergen. By contrast, the T cell receptor is viewed as a rich complex of stimulatory and co-stimulatory molecules, setting an array of thresholds to ensure a highly regulated response. Recent observations show that mast cells express various classes of co-stimulatory molecules that modulate their function. These molecules might therefore contribute to the outcome of mast cell-associated pathologies, and constitute new therapeutic targets in such diseases.

CCR1 and CCR5 chemokine receptors are involved in fever induced by LPS (E. coli) and RANTES in rats

This study, besides examining the involvement of CCR1 and CCR5 receptors in the LPS-induced fever (lipopolysaccharide, Escherichia coli) in male Wistar rats, evaluated if RANTES (regulated on activation, normal T cells expressed and secreted) injected into the preoptic area of the anterior hypothalamus (AH/POA) would promote an integrated febrile response via these receptors. Moreover, the effects of selective and non-selective cyclooxygenase blockers on both fever and the level of prostaglandin (PG)E(2) in the cerebrospinal fluid (CSF) after injection of RANTES into the AH/POA were also investigated. Met-RANTES, CCR1 and CCR5 receptor antagonist, reduced LPS-evoked fever dose dependently. RANTES microinjected into the AH/POA increased the rectal temperature of rats dose dependently and caused a significant decrease in the tail skin temperature and an increase (at 2.5 and 5 h) of the levels of PGE(2) in the CSF. Met-RANTES prevented the fever induced by RANTES. Ibuprofen abolished the fever caused by RANTES between 60 min and 2.5 h, and it reduced the temperature until the end of observation period. Celecoxib blocked the RANTES-induced fever, while indomethacin reduced it in the last 60 min of the experimental period. At 2.5 and 5 h all antipyretics brought the CSF PGE(2) level near to the control. These results indicate that CCR1 and CCR5 receptors are involved in the fever induced by systemic LPS and intrahypothalamic RANTES. RANTES promotes an integrated febrile response accompanied by an increase of CSF PGE(2). The inhibitory effects of celecoxib and ibuprofen suggest that PGE(2) was generated via COX-2. As indomethacin dissociates fever and the decrease of PGE(2) level during the RANTES-induced fever, an alternative COX-2-independent pathway or other mechanisms of action of celecoxib and ibuprofen might be considered.

p38 MAPK and ERK activation by 9-cis-retinoic acid induces chemokine receptors CCR1 and CCR2 expression in human monocytic THP-1 cells

9-cis-Retinoic acid (9CRA) plays an important role in the immune response; this includes cytokine production and cell migration. We have previously demonstrated that 9CRA increases expression of chemokine receptors CCR1 and CCR2 in human monocytes. To better understand how 9CRA induces CCR1 and CCR2 expression, we examined the contribution of signaling proteins in human monocytic THP-1 cells. The mRNA and surface protein up-regulation of CCR1 and CCR2 in 9CRA-stimulated cells were weakly blocked by the pretreatment of SB202190, a p38 MAPK inhibitor, and PD98059, an upstream ERK inhibitor. Activation of p38 MAPK and ERK1/2 was induced in both a time and dose-dependent manner after 9CRA stimulation. Both p38 MAPK and ERK1/2 phosphorylation peaked at 2 h after a 100 nM 9CRA treatment. 9CRA increased calcium influx and chemotactic activity in response to CCR1-dependent chemokines, Lkn-1/CCL15, MIP-1alpha/CCL3, and RANTES/CCL5, and the CCR2-specific chemokine, MCP-1/CCL2. Both SB202190 and PD98059 pretreatment diminished the increased calcium mobilization and chemotactic ability due to 9CRA. SB202190 inhibited the expression and functional activities of CCR1 and CCR2 more effectively than did PD98059. Therefore, our results demonstrate that 9CRA transduces the signal through p38 MAPK and ERK1/2 for CCR1 and CCR2 up-regulation, and may regulate the pro-inflammatory process through the p38 MAPK and ERK-dependent signaling pathways.

Role of human LZIP in differential activation of the NF-kappaB pathway that is induced by CCR1-dependent chemokines

Human leucine zipper protein (LZIP) associates with CC chemokine receptor 1 (CCR1) and this protein-protein interaction should play an important role in leukocyte cell mobility. LZIP is known to regulate leukotactin-1 (Lkn-1)-dependent cell migration without affecting the chemotactic activities of other CC chemokines that bind to CCR1. Since Lkn-1 is engaged in the transcriptional activation of nuclear factor kappaB (NF-kappaB) and subsequent activation of the chemoattractant ability of leukocytes, we investigated the regulatory role of LZIP in the NF-kappaB pathway that is induced by CCR1-dependent chemokines. LZIP increased NF-kappaB-dependent luciferase activity in response to Lkn-1 in HOS/CCR1 cells and THP-1 cells. However, the NF-kappaB-dependent luciferase activities induced by other CCR1-dependent chemokines were not affected by LZIP overexpression. LZIP also increased Lkn-1-induced chemotactic activity through activation of the NF-kappaB pathway, whereas LZIP did not affect either the transactivation of NF-kappaB or the chemotactic activities induced by other CCR1-dependent chemokines. Western blot analysis showed that LZIP increased the degradation of IkappaBalpha induced by Lkn-1 but not by other CCR1-dependent chemokines. Results from electrophoretic mobility shift assay (EMSA) showed that LZIP enhanced the Lkn-1-induced DNA-binding activity of NF-kappaB. These data indicate that LZIP functions as a positive regulator in the NF-kappaB activation pathway that is triggered by Lkn-1 without affecting the transcriptional activation of NF-kappaB induced by other CCR1-dependent chemokines.

CCR5 deficiency drives enhanced natural killer cell trafficking to and activation within the liver in murine T cell-mediated hepatitis

Natural killer (NK) cells are innate immune cells that are enriched in the liver, but the processes underlying NK cell trafficking to the liver and cellular activation within the liver of patients with T cell-mediated liver diseases remain poorly defined. Concanavalin A (Con A) hepatitis is a murine model mimicking many aspects of human T cell-mediated liver diseases. Here we demonstrate that severe hepatitis in CCR5-deficient (KO) mice is associated with increased hepatic NK cell recruitment driven by enhanced hepatic production of CCL5 acting via CCR1 and by enhanced hepatic NK cell activation relative to that observed in wild-type mice after Con A administration. Furthermore, NK cell depletion ameliorated severe hepatitis in CCR5 KO mice but did not alter hepatitis in wild-type mice after Con A treatment. We propose that in the setting of CCR5 deficiency NK cells assume a profound effector role in Con A hepatitis via enhanced CCL5-CCR1 driven hepatic recruitment in addition to augmented cytokine-driven NK cell activation to produce interferon-gamma. These results highlight the potential profound impact of altered chemokine receptor expression on the innate immune response in the setting of T cell-mediated hepatitis.

Structure–activity relationships of novel, highly potent, selective, and orally active CCR1 antagonists

Design and synthesis of a series of 3-amino-4-(2-(2-(4-benzylpiperazin-1-yl)-2-oxoethoxy)phenylamino)cyclobutenedione derivatives as novel CCR1 antagonists are described. Structure-activity relationship studies led to the identification of compound 22, which demonstrated potent binding activity, functional antagonism of CCR1 as well as good species cross-reactivity. In addition, compound 22 also showed desirable pharmacokinetic profiles and was selected for in vivo studies in the mouse collagen-induced arthritis model.

Neuropeptide substance P upregulates chemokine and chemokine receptor expression in primary mouse neutrophils

Neuropeptides play an important role in the active communication between the nervous and immune systems. Substance P (SP) is a prominent neuropeptide involved in neurogenic inflammation and has been reported to exert various proinflammatory actions on inflammatory leukocytes including neutrophils. The present study further investigated the modulatory effect of SP (1 muM) on chemokine production and chemokine receptor expression in primary mouse neutrophils. Our results showed that SP primed neutrophils for chemotactic responses not only to the CXC chemokine macrophage inflammatory protein (MIP)-2/CXCL2 but also to the CC chemokine MIP-1alpha/CCL3. The activating effect of SP on neutrophils was further evidenced by upregulation of the CD11b integrin, the activation marker of neutrophils. SP induced both the mRNA and protein expression of the chemokines MIP-1alpha/CCL3 and MIP-2/CXCL2 in neutrophils and upregulated the chemokine receptors CC chemokine receptor (CCR)-1 and CXC chemokine receptor (CXCR)-2. This stimulatory effect on chemokine and chemokine receptor expression in neutrophils was further found to be neurokinin-1 receptor (NK-1R) specific. Pretreatment with selective NK-1R antagonists inhibited SP-triggered activation of neutrophils and chemokine and chemokine receptor upregulation. Moreover, SP-induced chemokine upregulation was NF-kappaB dependent. SP time dependently induced NF-kappaB p65 binding activity, IkappaBalpha degradation, and NF-kappaB p65 nuclear translocation in neutrophils. Inhibition of NF-kappaB activation with its inhibitor Bay11-7082 (10 muM) abolished SP-induced NF-kappaB binding activity and upregulation of MIP-1alpha/CCL3 and MIP-2/CXCL2 in neutrophils. Together, these results suggest that SP exerts a direct stimulatory effect on the expression of chemokines and chemokine receptors in mouse neutrophils. The effect is NK-1R mediated, involving NF-kappaB activation.

The role of interstitial macrophages in nephropathy of type 2 diabetic db/db mice

Diabetic nephropathy is associated with interstitial macrophage infiltrates, but their contribution to disease progression is unclear. We addressed this question by blockade of chemokine receptor (CCR)1 because CCR1 mediates the macrophage recruitment to the renal interstitium. In fact, when CCR1 was blocked with BL5923, a novel orally available CCR1 antagonist, the interstitial recruitment of ex vivo labeled macrophages was markedly decreased in uninephrectomized male db/db mice with advanced diabetic nephropathy. Likewise, BL5923 (60 mg/kg, twice a day) orally administered from months 5 to 6 of life reduced the numbers of interstitial macrophages in uninephrectomized db/db mice. This was associated with reduced numbers of Ki-67 proliferating tubular epithelial and interstitial cells, tubular atrophy, and interstitial fibrosis in uninephrectomized db/db mice. Glomerular pathology and proteinuria were not affected by the CCR1 antagonist. BL5923 reduced renal mRNA expression of Ccl2, Ccr1, Ccr2, Ccr5, transforming growth factor-beta1, and collagen I-alpha1 when compared with untreated uninephrectomized male db/db mice of the same age. Thus, we identified a previously unrecognized role for interstitial macrophages for tubulointerstitial injury, loss of peritubular microvasculature, interstitial inflammation, and fibrosis in type 2 diabetic db/db mice. These data identify oral treatment with the CCR1 antagonist BL5923 as a potential therapy for late-stage diabetic nephropathy.

Profiles of chemokine receptors in melanocytic lesions: de novo expression of CXCR6 in melanoma

Selective expression of certain chemokine receptors by melanoma cells and the presence of their ligands in tissues might govern organ site-specific metastasis. Because the expression profile of chemokine receptors in tissues of melanocytic origin is unknown, we performed a comprehensive study on melanocytic tissue samples investigating the expression of 18 chemokine receptors at the mRNA level by real-time polymerase chain reaction, using a semiquantitative approach, and of 3 chemokine receptors (CXCR6, CCR9, and XCR1) at the protein level. We report on the de novo expression of CXCR6 in primary melanomas and melanoma metastases, but absence in melanoma cell lines and congenital nevi. CXCR4 and CCR1 were the only 2 chemokine receptors that were consistently expressed in melanocytes, melanoma cell lines, primary, and metastatic melanoma; CCR1 expression increased significantly over progression. CCR9 and XCR1 transcripts were found in melanocytic lesions, and expression was confirmed by immunohistochemistry. Transcripts for CCR10 were not found in any of the lesions, but in some melanoma cell lines. Expression of CCR7 was observed in primary melanomas and some metastases. CCR5 was exclusively expressed in primary melanomas and some cutaneous metastases. Results revealed a restricted and differential pattern of chemokine receptor expression in melanoma tissue, which varies substantially from the expression profile of melanoma cell lines and warrants functional studies on some receptors.

Deletion of the chemokine receptor CCR1 prolongs corneal allograft survival

PURPOSE

Many corneal grafts undergo immune rejection, and current therapies are associated with many side effects. The purpose of this study was to identify critical chemokine pathways involved in generating the alloimmune response to corneal transplants.

METHODS

Orthotopic corneal transplantation was performed in fully mismatched strains. Cytokine and chemokine receptor gene expression was determined by the RNase protection assay. Knockout (KO) strains for chemokine-chemokine receptors that are upregulated after transplantation underwent corneal transplantation. Results derived from KO murine hosts were compared with cyclosporine (Cy) therapy. In addition to graft survival, graft infiltration, allospecific delayed-type hypersensitivity (DTH), and cytokine expression were compared among the recipient groups.

RESULTS

Initial experiments revealed gene upregulation of the chemokine receptors CCR1, -2, and -5 after corneal allorejection. Although CCR1 KO hosts showed a significant increase in graft survival compared with wild-type (WT) hosts, allografts in CCR5, CCR2/CCL3(MIP-1alpha), CXCR3, CXCL10/IP-10, and CCL3/MIP-1alpha KO mice did not show a significant improvement in graft survival. Further, CCR1 KO hosts showed a significantly higher survival rate than with systemic Cy therapy in WT hosts. Moreover, graft infiltration by leukocytes and gene expression of proinflammatory cytokines were reduced in CCR1 KO mice compared with both Cy treated and untreated WT mice, as was the induction of allospecific DTH.

CONCLUSIONS

These studies provide, for the first time, evidence that targeting of specific chemokine pathways can significantly promote survival of corneal transplants, and suggest that select deletion or suppression of CCR1 can be a useful therapeutic target in corneal transplant immunity.

Met-RANTES ameliorates fibrous airway obliteration and decreases ERK expression in a murine model of bronchiolitis obliterans

OBJECTIVES

Bronchiolitis obliterans (BO) is the main cause of late mortality among long-term survivors of lung transplantation. Chemokine-chemokine receptor (CCR) interaction and subsequent recruitment of infiltrating cells to the graft are early events in the development of chronic rejection of transplanted lungs. The present study investigated whether blockade of chemokine receptors CCR1 and CCR5 with Met-regulated-on-activation, normal T cells expressed and secreted (RANTES), an amino-terminal modified derivative of RANTES/CCL5, affects the development of BO in murine model and we sought to determine the expression of RANTES/CCL5 and their relationship with extracellular signal-regulated kinase (ERK).

MATERIALS AND METHODS

BALB/c mouse tracheas were heterotopically transplanted into C57Black6 recipients and treated for 21 days with either Met-RANTES at 20 microg/day or vehicle. Animals were killed at 21 days after transplantation for histologic examination of ERK expression.

RESULTS

RANTES/CCL5 was highly expressed in allografts compare to isografts. Met-RANTES treatment ameliorated fibrous airway obliteration in a mouse model of BO and decreased ERK expression.

CONCLUSION

Blockade of chemokine receptors by Met-RANTES ameliorated airway obliteration and decreased ERK expression. These findings suggest that chemokine receptors CCR1 and CCR5 play significant roles in the development of chronic rejection and ERK may be a new molecular target for chronic rejection.

Treatment with BX471, a CC chemokine receptor 1 antagonist, attenuates systemic inflammatory response during sepsis

Sepsis is a complex clinical syndrome resulting from a harmful host inflammatory response to infection. Chemokines and their receptors play a key role in the pathogenesis of sepsis. BX471 is a potent nonpeptide CC chemokine receptor-1 (CCR1) antagonist in both human and mouse. The aim of the present study was to evaluate the effect of prophylactic and therapeutic treatment with BX471 on cecal ligation and puncture-induced sepsis in the mouse and to investigate the underlying mechanisms. In sepsis induced by cecal ligation and puncture, treatment with BX471 significantly protected mice against lung and liver injury by attenuating MPO activity, an indicator of neutrophil recruitment in lungs and livers and attenuating lung and liver morphological changes in histological sections. Blocking CCR1 by BX471 also downregulated ICAM-1, P-selectin, and E-selectin expression at mRNA and protein levels in lungs and livers compared with placebo-treated groups. These findings suggest that blockage of CCR1 by specific antagonist may represent a promising strategy to prevent disease progression in sepsis.

RSV-infected airway epithelial cells cause biphasic up-regulation of CCR1 expression on human monocytes

Respiratory syncytial virus (RSV) infection can cause extensive airway inflammation, which is orchestrated by chemokines and their receptors. RSV-infected epithelial cells secrete many cytokines and chemokines, but little is known about regulation of chemokine receptors on target cells. We investigated the effects of conditioned media (CM) from RSV-infected epithelial cells on monocyte CCR1, CCR2, and CCR5 expression. RSV-CM but not control-CM stimulated a biphasic increase in cell-surface CCR1, and levels peaked at 36 h and 96 h poststimulation. Similar CCR1 up-regulation occurred on monocyte-derived macrophages. Cytochlasin D and colchicine blocked both peaks of expression, demonstrating requirement of a functional cytoskeleton. Intracellular staining revealed little internal sequestration of CCR1 protein, and CCR1 up-regulation was inhibited by actinomycin D and cycloheximide, indicating that both waves of RSV-CM-induced surface CCR1 expression were dependent on de novo transcription and protein synthesis. Cytokine-neutralizing experiments showed that the effects of RSV-CM were decreased by blocking TNF-alpha (percent inhibition=51+/-2.3% at 36 h peak and 42+/-7.7% at 96 h peak) and to a lesser extent, IL-1 (percent inhibition=32+/-7.2% at 36 h and 23+/-2.9% at 96 h). In summary, RSV-CM causes a biphasic up-regulation of surface CCR1 on monocytes, which is dependent on an intact cytoskeleton, requires new gene transcription and protein synthesis, and is mediated in part by the proinflammatory cytokines TNF-alpha and IL-1.

SMAD4-deficient intestinal tumors recruit CCR1+ myeloid cells that promote invasion

Inactivation of TGF-beta family signaling is implicated in colorectal tumor progression. Using cis-Apc(+/Delta716) Smad4(+/-) mutant mice (referred to as cis-Apc/Smad4), a model of invasive colorectal cancer in which TGF-beta family signaling is blocked, we show here that a new type of immature myeloid cell (iMC) is recruited from the bone marrow to the tumor invasion front. These CD34(+) iMCs express the matrix metalloproteinases MMP9 and MMP2 and the CC-chemokine receptor 1 (CCR1) and migrate toward the CCR1 ligand CCL9. In adenocarcinomas, expression of CCL9 is increased in the tumor epithelium. By deleting Ccr1 in the background of the cis-Apc/Smad4 mutant, we further show that lack of CCR1 prevents accumulation of CD34(+) iMCs at the invasion front and suppresses tumor invasion. These results indicate that loss of transforming growth factor-beta family signaling in tumor epithelium causes accumulation of iMCs that promote tumor invasion.

Piperazinyl CCR1 antagonists--optimization of human liver microsome stability

The synthesis, biological activity, and pharmacokinetic profile of CCR1 antagonists are described.

Chemokines and chemokine receptors in renal transplantation — from bench to bedside

Attraction of mononuclear cells to sites of inflammation requires a close interplay of the inflammatory signal presented via chemokines and specific receptors on effector cells. First studies on acute renal transplant rejection demonstrated the involvement of CC-chemokines, such as RANTES, MIP-1alpha, MIP-1beta and MCP-1, as well as CXC-chemokines such as IL-8 and IP-10, correlating with expression of the corresponding chemokine receptors, CCR1, CCR5 and CCR2 as well as CXCR3. Since then, the pathophysiologic relevance has been extended to chronic allograft nephropathy and transplant glomerulopathy. Chemokine expression can be triggered by different stimuli, e.g. brain death, ischemia, HLA-mismatch and infection. Furthermore, anti-inflammatory chemokines have been identified. Chemokine receptor 7, e.g. enhances homing of lymphocytes to lymphatic tissues and the Duffy antigen receptor, DARC, a non-specific receptor that binds and inactivates different chemokines. While measurement of chemokine expression in clinical transplantation may facilitate the differential diagnosis of allograft dysfunction, knowledge of the chemokine network has also widened the understanding of transplant rejection and opened novel therapeutic approaches. Observations from humans with mutations of the chemokine network as well as transplantation of animals with targeted deletions in this system suggest that manipulations of chemokine signalling may improve the success rates of transplantation. Blocking chemokines unselectively with Met-RANTES or specifically with small molecule inhibitors of various chemokine receptors has lead to improved outcome in animal models. Currently, first human trials are under way to investigate drugs that stimulate lymphocyte homing. Inhibitors of CCR1 and CCR5 are being tested for other human diseases and may eventually be available in transplantation. Nonetheless, chemokine blockade my rather serve as an adjunct in the management of transplant recipients than a new "magic bullet".

Trypanosoma cruzi-triggered meningoencephalitis is a CCR1/CCR5-independent inflammatory process

Encephalitis rarely occurs during acute Trypanosoma cruzi infection. However, the central nervous system (CNS) is the major site of infection reactivation in immunocompromised patients. We show that the acute T. cruzi-triggered CD8-enriched meningoencephalitis paralleled the in situ expression of CCL3/MIP-1alpha and CCL5/RANTES mRNA. The frequency of CCR5-bearing cells was increased among peripheral blood mononuclear cells (PBMC) of infected mice. Further, CCL5/RANTES-driven in vitro PBMC migration was partially abrogated by the CCR1/CCR5 antagonist Met-RANTES. However, Met-RANTES treatment of infected mice altered neither parasitism nor intensity and nature of the CNS inflammation, indicating that T. cruzi-elicited meningoencephalitis is a CCR1/CCR5 independent process.

Beneficial effects of CCR1 blockade on the progression of chronic renal allograft damage

The biology of chemokines and their receptors have been linked to the development of chronic allograft damage. Effects of CCR1 antagonist BX 471 were studied in a Fischer to Lewis renal transplantation model at days 10, 21 and 42 after transplantation. BX 471 treatment did not effectively reduce signs of acute rejection at day 10 but significantly improved allograft function and morphology at day 21 posttransplantation. When therapy was initiated on day 21 after transplantation, glomerulosclerosis and tubulointerstitial fibrosis were significantly inhibited by day 42 posttransplantation. Parallel decrease in infiltrating and proliferating mononuclear cells (ED1, CD8 and Ki67) was observed in treated allografts. Expression of acute phase reactive and proinflammatory genes (HO-1, osteopontin) and molecules associated with fibrosis (PAI-1, TGF-beta1, biglycan) was downregulated at day 21; reduced collagen deposition was observed, parallel to a significant lower number of alpha-SMA+ interstitial myofibroblasts. In situ hybridization demonstrated that biglycan expression was reduced following CCR1 blockade in interstitium of treated allografts. CCR1 antagonism was found to inhibit CCL5-induced secretion of biglycan by macrophages in vitro. CCR1 blockade significantly inhibited development and progression of chronic allograft damage. CCR1 antagonists may represent a therapeutic option for chronic inflammation and fibrosis in renal grafts.

Treatment with BX471, a nonpeptide CCR1 antagonist, protects mice against acute pancreatitis-associated lung injury by modulating neutrophil recruitment

OBJECTIVES

Chemokines and their receptors play a key role in the pathogenesis of acute pancreatitis. BX471 is a potent nonpeptide CC chemokine receptor 1 antagonist in both human and mouse. The aim of the present study was to evaluate the effect of prophylactic and therapeutic treatment with BX471 on experimental acute pancreatitis in the mouse and to investigate the underlying mechanisms.

METHODS

Acute pancreatitis was induced in mice by hourly intraperitoneal injection of cerulein. BX471 was administered either prophylactically or therapeutically, and pancreatic inflammation and lung injury were assessed. The expression of intercellular adhesion molecule 1, P-selectin, and E-selectin was studied by reverse transcriptase-polymerase chain reaction and immunohistochemistry.

RESULTS

In cerulein-induced acute pancreatitis, treatment with BX471 significantly protected mice against lung injury associated with cerulein-induced pancreatitis by attenuating myeloperoxidase activity, an indicator of neutrophil recruitment, and lung morphological changes in histological sections. Treatment with BX471 had little effect on pancreatic damage. Blocking CC chemokine receptor 1 by BX471 also down-regulated intercellular adhesion molecule 1, P-selectin, and E-selectin expression at mRNA and protein levels in both lungs and pancreas compared with vehicle-treated groups.

CONCLUSIONS

These findings suggest that interfering with neutrophil migration and activation by targeting CC chemokine receptor 1 may represent a promising strategy to prevent disease progression in acute pancreatitis.

Downregulation of CCR1 inhibits human hepatocellular carcinoma cell invasion

CC chemokine receptor 1 (CCR1) has an important role in the recruitment of leukocytes to the site of inflammation. The migration and metastasis of tumor cells shares many similarities with leukocyte trafficking, which is mainly regulated by chemokine receptor-ligand interactions. CCR1 is highly expressed in hepatocellular carcinoma (HCC) cells and tissues with unknown functions. In this study, we silenced CCR1 expression in the human HCC cell line HCCLM3 using artificial microRNA (miRNA)-mediated RNA interference (RNAi) and examined the invasiveness and proliferation of CCR1-silenced HCCLM3 cells and the matrix metalloproteinase (MMP) activity. The miRNA-mediated knockdown expression of CCR1 significantly inhibited the invasive ability of HCCLM3 cells, but had only a minor effect on the cellular proliferation rate. Moreover, CCR1 knockdown significantly reduced the secretion of MMP-2. Together, these findings indicate that CCR1 has an important role in HCCLM3 invasion and that CCR1 might be a new target of HCC treatment.

Expression of the chemokine receptor CCR1 in human renal allografts

BACKGROUND

Chemokines are involved in the recruitment of leukocytes to vascularized allografts. CCR1 is a receptor for various proinflammatory chemokines and CCR1 blockade reduces renal allograft injury in rabbits. The purpose of the study was to characterize CCR1-positive cells in human renal allografts.

METHODS

Formalin-fixed, paraffin-embedded allograft nephrectomies (n = 9) and non-involved parts of tumour nephrectomies (n = 10) were studied. Immunohistochemistry for CCR1, CD3 and CD68 was performed on consecutive sections. Double immunofluorescence for CCR1 and CD3, CD20, CD68, DC-SIGN and S100 was used on selected cases. Expression of CCR1 mRNA and the ligands CCL3 and CCL5 was studied in renal allograft biopsies with acute rejection (n = 10), with chronic allograft nephropathy (n = 8) and controls (n = 8).

RESULTS

CCR1 protein was expressed by circulating cells in glomerular and peritubular capillaries, colocalizing with CD68. In renal allografts CCR1-positive cells were present within glomerular tufts, but only scattered CCR1-positive cells were found in tubulointerstitial infiltrates. CCR1 did not colocalize with the majority of CD68-positive cells in the interstitium. The small number of CCR1-positive interstitial cells were identified as CD20- or DC-SIGN-positive by double immunofluorescence. CCR1 mRNA was significantly increased in renal biopsies with acute allograft rejection (P < 0.001), and with chronic allograft nephropathy (P < 0.05), it correlated with the expression of CCL3 and CCL5, and with serum-creatinine.

CONCLUSIONS

CCR1 mRNA expression was associated with renal function in allografts. CCR1 protein expression was restricted to monocytes, CD20-positive B cells and DC-SIGN-positive dendritic cells. Thus most interstitial macrophages were CCR1 negative, which may relate to down-regulation after migration into the interstitium in human renal allografts.

Regulation of human LZIP expression by NF-kappaB and its involvement in monocyte cell migration induced by Lkn-1

Human LZIP is a transcription factor that is involved in leukocyte cell mobility. Expression of LZIP is known to differentially regulate monocyte cell migration induced by CCR1-dependent chemokines. However, its transcriptional regulation has not been characterized. Our results indicate that Lkn-1 induces LZIP expression in a time- and dose-dependent manner, and the induction of LZIP shows an immediate early response to Lkn-1. We identified and cloned approximately 1.4 kb of the LZIP promoter from a human genomic DNA. To identify regulatory elements controlling restricted expression of LZIP, deletion mutants were constructed from the 1469-bp LZIP promoter region (-1219/+251) linked to the luciferase reporter gene. Maximal promoter activity was contained within 613 bp from the tentative transcription initiation site and was sharply reduced in a truncated construct (-338/+251). This promoter sequence contained consensus NF-kappaB- and Sp-1-binding sites. Results from an inhibitor assay showed that NF-kappaB is involved in Lkn-1-induced LZIP expression, but Sp-1 is not. We also demonstrated that NF-kappaB binds to the LZIP promoter and that the binding is specific, as revealed by an electrophoretic mobility shift assay and a mutation analysis. Chemotaxis analysis showed that LZIP expression because of the NF-kappaB subfamily is specifically involved in Lkn-1-induced chemotaxis. Our findings suggest that transcription factor NF-kappaB plays an important role in regulation of LZIP expression, and LZIP expression regulates the monocyte cell migration induced by Lkn-1.

Ccr5 But Not Ccr1 Deficiency Reduces Development of Diet-Induced Atherosclerosis in Mice

OBJECTIVE

Chemokines and their receptors are crucially involved in the development of atherosclerotic lesions by directing monocyte and T cell recruitment. The CC-chemokine receptors 1 (CCR1) and 5 (CCR5) expressed on these cells bind chemokines implicated in atherosclerosis, namely CCL5/RANTES. Although general blockade of CCL5 receptors reduces atherosclerosis, specific roles of CCR1 and CCR5 have not been unequivocally determined.

METHODS AND RESULTS

We provide two independent lines of investigation to dissect the effects of Ccr1 and Ccr5 deletion in apolipoprotein E-deficient (ApoE-/-) mice in a collaboration between Aachen/Germany and Geneva/Switzerland. Different strains of ApoE-/- Ccr5-/- mice, ApoE-/- Ccr1-/- mice or respective littermates, were fed a high-fat diet for 10 to 12 weeks. Plaque areas were quantified in the aortic roots and thoracoabdominal aortas. Concordantly, both laboratories found that lesion formation was reduced in ApoE-/- Ccr5-/- mice. Plaque quality and immune cells were assessed by immunohistochemistry or mRNA analysis. Whereas lesional macrophage content, aortic CD4, and Th1-related Tim3 expression were reduced, smooth muscle cell (SMC) content and expression of interleukin-10 in plaques, lesional SMCs, and splenocytes were elevated. Protection against lesion formation by Ccr5 deficiency was sustained over 22 weeks of high-fat diet or over 26 weeks of chow diet. Conversely, plaque area, T cell, and interferon-gamma content were increased in ApoE-/- Ccr1-/- mice.

CONCLUSIONS

Genetic deletion of Ccr5 but not Ccr1 in ApoE-/- mice protects from diet-induced atherosclerosis, associated with a more stable plaque phenotype, reduced mononuclear cell infiltration, Th1-type immune responses, and increased interleukin-10 expression. This corroborates CCR5 as a promising therapeutic target.

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

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

Regulatory effects of vasoactive intestinal peptide on the migration of mature dendritic cells

The neuropeptide vasoactive intestinal peptide (VIP), released within lymphoid organs from nerve terminals and/or immune cells, plays a significant anti-inflammatory role. It was reported that VIP can induce regulatory dendritic cells (DCs) and promote Th2-type responses. However, the regulatory effect of VIP on the migration and expression of chemokine receptors by DC is mostly unknown. In the present study, we show that VIP exerts a differential effect on the expression of CCR1 and CCR7 by lipopolysaccharide (LPS)-treated mature DCs (mDCs) at both protein and mRNA levels. It up-regulates CCR1 expression but down-regulates CCR7 expression in LPS-stimulated mature DC, thereby differentially regulating the migration of mature DCs in response to CCL5 and CCL19. Our data indicate that VIP functions as a key endogenous anti-inflammatory agent by inhibiting migration of mDCs to draining lymph nodes, thus preventing the induction of an inflammatory immune response.

Lactonisation—a degradation pathway for active pharmaceutical compounds: an in silico study in amorphous trehalose

The lactonisation of a CCR1 inhibitor (CC chemokine receptor 1, involved in autoimmune diseases) featuring a hydroxyl group in a gamma-position (gamma-OH) with respect to an amide group has been investigated in silico. The two key steps of the lactonisation reaction are (i) rearrangement to an optimal conformation and (ii) the formation of the lactone (ring closure) and expulsion of NH3. Quantum chemical calculations in the gas phase were employed to identify conformers of the molecule with favorable starting geometries for a lactonisation reaction. In total, calculations of 1296 conformers revealed that it is energetically feasible for an inhibitor molecule to adopt a conformation where the carbon atom of the amide group (C(amide)) is suitably close to the oxygen atom of the gamma-OH (O(gamma)) to facilitate a successful lactonisation reaction. Additionally, molecular dynamics methods were used to show that rearrangement to a suitable conformer for lactonisation to occur happens to a lesser extent when the CCR1 inhibitor was embedded in an amorphous trehalose matrix (a model carbohydrate excipient). The mechanism of the actual lactonisation was investigated using the complete Linear Synchronous Transit/Quadratic Synchronous Transit (LST/QST) method. This was performed in both the gas phase and in water and was found to be a concerted reaction.

MSC–DC interactions: MSC inhibit maturation and migration of BM-derived DC

BACKGROUND

Mesenchymal stromal cells (MSC) comprise one of the BM stromal cells that are known to support hematopoiesis. It has also been suggested recently that MSC display immunosuppressive capacities through inhibiting the differentiation of monocyte-derived DC. DC travel to the lymph nodes (LN) to present Ag to T cells, and CCL21 is the chemokine that plays an important role in DC migration into the T-cell area of LN. We addressed the effect of MSC on this chemotactic activity of DC, one of the typical characteristics upon maturation.

METHODS

BM cells were isolated and then cultured for generation of myeloid DC in the presence of GM-CSF and/or lipopolysaccharide with or without MSC. MSC were identified by flow cytometry of the immunologic markers and by performing colony-forming unit fibroblast assay. Migration of DC was observed with a newly developed time-lapse video microscopic technique.

RESULTS

MSC co-culture inhibited the initial differentiation of DC, as well as their maturation. The matured DC actively migrated directionally in response to CCL21, a powerful DC-attracting chemokine, whereas the MSC co-cultured DC did not.

DISCUSSION

Collectively, the findings of these experiments raise the possibility that MSC suppress the migratory function of DC and so they may serve immunoregulatory activities through the modulation of the Ag-presenting function of DC.

Ligand up-regulation does not correlate with a role for CCR1 in pathogenesis in a mouse model of non-lymphocyte-mediated neurological disease

CCR1 ligands, including CCL3, CCL5, and CCL7, are up-regulated in a number of neurological disorders in humans and animal models. CCR1 is expressed by multiple cell types in the central nervous system (CNS), suggesting that receptor signaling by neuronal cell types may influence pathogenesis. In the current study, the authors used a mouse model of retrovirus infection to study the contribution of CCR1 to neuropathogenesis in the absence of lymphocyte recruitment to the CNS. In this model, infection of neonatal mice with the neurovirulent retrovirus Fr98 results in increased expression of proinflammatory chemokines in the CNS, activation of glial cells, and development of severe neurological disease. Surprisingly, no difference in neuropathogenesis was observed between CCR1-sufficient and CCR1-deficient mice following infection with the neuropathogenic virus Fr98. CCR1 was also not necessary for control of virus replication in the brain or virus-induced activation of astroglia. Additionally, CCR1 deficiency did not affect the up-regulation of its ligands, CCL3, CCL5, or CCL7. Thus, CCR1 did not appear to have a notable role in Fr98-induced pathogenesis, despite the correlation between ligand expression and disease development. This suggests that in the absence of inflammation, CCR1 may have a very limited role in neuropathogenesis.

Macrophage inflammatory protein (MIP)1alpha and MIP1beta differentially regulate release of inflammatory cytokines and generation of tumoricidal monocytes in malignancy

The C-C chemokines, macrophage inflammatory protein (MIP)1alpha and MIP1beta are potent chemoattractants for the monocytes, which form an important component of the stroma of tumor tissue and may regulate tumor growth and associated inflammation. We examined the role of MIP1alpha and MIP1beta in inducing the release of inflammatory cytokines and the generation of tumoricidal monocytes from the peripheral blood monocytes (PBM) of healthy women and patients with carcinoma of breast (CaBr). Interleukin-1 (IL-1) and tumor necrosis factor (TNF) alpha release by the PBM was markedly stimulated by MIP1alpha in CaBr patients, but only marginally so in healthy women. In contrast, MIP1beta stimulated the release of these cytokines by the PBM of healthy women, but failed to do so in CaBr patients. MIP1alpha, but not MIP1beta, synergized with LPS in inducing the release of IL-1 from the PBM of both healthy women and CaBr patients. Both MIP1alpha and MIP1beta augmented respiratory bursts in PBM and generated tumoricidal PBM that killed T24 cells, MIP1alpha being more effective in CaBr patients and MIP1beta in healthy women. IFN-gamma co-stimulated and IL-4 suppressed MIP1alpha and beta-induced cytotoxicity in PBM. The synergy of IFN-gamma was more marked with MIP1alpha than with MIP1beta. The differential effects of MIP1alpha and MIP1beta on the PBM of healthy women and CaBr patients co-related with the levels of expression of CCR1 and CCR5 in these monocytes. The expression of CCR5 was higher than that of CCR1 in the PBM of healthy women and the PBM of the CaBr patients showed overexpression of CCR1 and downregulation of CCR5.

Blockade of chemokine signaling in patients with multiple sclerosis

We assessed the safety and efficacy of orally administered CC chemokine receptor 1 (CCR1) antagonist in 105 patients with relapsing/remitting MS (RRMS) in a 16-week, randomized, double-blind, placebo-controlled trial. The primary endpoint was the cumulative number of newly active lesions on serial MRI scans. Other MRI, immunologic, and clinical outcomes were also explored. No significant treatment difference was observed for any tested MRI variable. CCR1 does not contribute to initial leukocyte infiltration in RRMS.

Role of CCR1 and CCR5 in homing and growth of multiple myeloma and in the development of osteolytic lesions: a study in the 5TMM model

Multiple myeloma (MM) is a plasma cell malignancy, characterized by the localization of the MM cells in the bone marrow (BM), where they proliferate and induce osteolysis. The MM cells first need to home or migrate to the BM to receive necessary survival signals. In this work, we studied the role of CCR1 and CCR5, two known chemokine receptors, in both chemotaxis and osteolysis in the experimental 5TMM mouse model. A CCR1-specific (BX471) and a CCR5-specific (TAK779) antagonist were used to identify the function of both receptors. We could detect by RT-PCR and flow cytometric analyses the expression of both CCR1 and CCR5 on the cells and their major ligand, macrophage inflammatory protein 1alpha (MIP1alpha) could be detected by ELISA. In vitro migration assays showed that MIP1alpha induced a 2-fold increase in migration of 5TMM cells, which could only be blocked by TAK779. In vivo homing kinetics showed a 30% inhibition in BM homing when 5TMM cells were pre-treated with TAK779. We found, in vitro, that both inhibitors were able to reduce osteoclastogenesis and osteoclastic resorption. In vivo end-term treatment of 5T2MM mice with BX471 resulted in a reduction of the osteolytic lesions by 40%; while TAK779 treatment led to a 20% decrease in lesions. Furthermore, assessment of the microvessel density demonstrated a role for both receptors in MM induced angiogenesis. These data demonstrate the differential role of CCR1 and CCR5 in MM chemotaxis and MM associated osteolysis and angiogenesis.

Balancing focused combinatorial libraries based on multiple GPCR ligands

G-Protein coupled receptors (GPCRs) are important targets for drug discovery, and combinatorial chemistry is an important tool for pharmaceutical development. The absence of detailed structural information, however, limits the kinds of combinatorial design techniques that can be applied to GPCR targets. This is particularly problematic given the current emphasis on focused combinatorial libraries. By linking an incremental construction method (OptDesign) to the very fast shape-matching capability of ChemSpace, we have created an efficient method for designing targeted sublibraries that are topomerically similar to known actives. Multi-objective scoring allows consideration of multiple queries (actives) simultaneously. This can lead to a distribution of products skewed towards one particular query structure, however, particularly when the ligands of interest are quite dissimilar to one another. A novel pivoting technique is described which makes it possible to generate promising designs even under those circumstances. The approach is illustrated by application to some serotonergic agonists and chemokine antagonists.

Pharmacological blockade of CCR1 ameliorates murine arthritis and alters cytokine networks in vivo

BACKGROUND AND PURPOSE

The chemokine receptor CCR1 is a potential target for the treatment of rheumatoid arthritis. To explore the impact of CCR1 blockade in experimental arthritis and the underlying mechanisms, we used J-113863, a non-peptide antagonist of the mouse receptor.

EXPERIMENTAL APPROACH

Compound J-113863 was tested in collagen-induced arthritis (CIA) and three models of acute inflammation; Staphylococcus enterotoxin B (SEB)-induced interleukin-2 (IL-2), delayed-type hypersensitivity (DTH) response, and lipopolysaccharide (LPS)-induced tumour necrosis factoralpha (TNFalpha) production. In the LPS model, CCR1 knockout, adrenalectomised, or IL-10-depleted mice were also used. Production of TNFalpha by mouse macrophages and human synovial membrane samples in vitro were also studied.

KEY RESULTS

Treatment of arthritic mice with J-113863 improved paw inflammation and joint damage, and dramatically decreased cell infiltration into joints. The compound did not inhibit IL-2 or DTH, but reduced plasma TNFalpha levels in LPS-treated mice. Surprisingly, CCR1 knockout mice produced more TNFalpha than controls in response to LPS, and J-113863 decreased TNFalpha also in CCR1 null mice, indicating that its effect was unrelated to CCR1. Adrenalectomy or neutralisation of IL-10 did not prevent inhibition of TNFalpha production by J-113863. The compound did not inhibit mouse TNFalpha in vitro, but did induce a trend towards increased TNFalpha release in cells from synovial membranes of rheumatoid arthritis patients.

CONCLUSIONS AND IMPLICATIONS

CCR1 blockade improves the development of CIA, probably via inhibition of inflammatory cell recruitment. However, results from both CCR1-deficient mice and human synovial membranes suggest that, in some experimental settings, blocking CCR1 could enhance TNF production.

Is Endometriosis Associated with Systemic Subclinical Inflammation?

Endometriosis is a pelvic inflammatory process with altered function of immune-related cells and increased number of activated macrophages in the peritoneal environment that secrete various local products, such as growth factors and cytokines. The elevation of cytokines and other factors in the peritoneal fluid is accompanied by the elevation of similar factors, such as CRP, SAA, TNF-alpha, MCP-1, IL-6, IL-8 and CCR1, in the peripheral blood of patients with endometriosis. CD44+ and CD14+ monocytes are significantly increased, while CD3+ T lymphocytes and CD20+ B lymphocytes show modest, but significant decrease in peripheral blood of women with endometriosis. This indicates that endometriosis could be viewed as a local disease with systemic subclinical manifestations. This review provides an overview of data on the changes of various factors in peripheral blood and their potential use as diagnostic tools in patients with endometriosis.

Androgen receptor negatively influences the expression of chemokine receptors (CXCR4, CCR1) and ligand-mediated migration in prostate cancer DU-145

We previously reported that androgen receptor (AR) plays a role in the regulation of adhesion to the extracellular matrix and invasion of human prostate cancer cells by influencing the expression of specific integrin subunits. It is now considered that chemokines play a significant role in organ-selective cancer metastasis. In this study, we hypothesized that AR may influence the expression of these chemokine receptors and cell function. The mRNA expression of chemokine receptors in human prostate cancer cell line DU-145 and DU-145 cells expressing AR (DU-145/AR) was investigated by RT-PCR. DU-145 cells selectively expressed CXCR4 and CCR1 mRNA at high levels compared with DU-145/AR cells. DU-145 showed vigorous migratory responses to its ligand CXCL12 (also called stromal-derived factor-1alpha, SDF-1alpha) and CCL3 (also called macrophage inflammatory protein-1, MIP-1alpha). In contrast, neither CXCL12 nor CCL3 affected the migration of DU-145/AR cells. These results indicate that expression of AR down-regulates the migratory responses of human prostate cancer cells via chemokine and its receptor systems.

Predictions of CCR1 chemokine receptor structure and BX 471 antagonist binding followed by experimental validation

A major challenge in the application of structure-based drug design methods to proteins belonging to the superfamily of G protein-coupled receptors (GPCRs) is the paucity of structural information (1). The 19 chemokine receptors, belonging to the Class A family of GPCRs, are important drug targets not only for autoimmune diseases like multiple sclerosis but also for the blockade of human immunodeficiency virus type 1 entry (2). Using the MembStruk computational method (3), we predicted the three-dimensional structure of the human CCR1 receptor. In addition, we predicted the binding site of the small molecule CCR1 antagonist BX 471, which is currently in Phase II clinical trials (4). Based on the predicted antagonist binding site we designed 17 point mutants of CCR1 to validate the predictions. Subsequent competitive ligand binding and chemotaxis experiments with these mutants gave an excellent correlation to these predictions. In particular, we find that Tyr-113 and Tyr-114 on transmembrane domain 3 and Ile-259 on transmembrane 6 contribute significantly to the binding of BX 471. Finally, we used the predicted and validated structure of CCR1 in a virtual screening validation of the Maybridge data base, seeded with selective CCR1 antagonists. The screen identified 63% of CCR1 antagonists in the top 5% of the hits. Our results indicate that rational drug design for GPCR targets is a feasible approach.

A natural CCL5/RANTES variant antagonist for CCR1 and CCR3

The N-terminal domain of the chemokine CCL5/regulated upon activation normal T cell expressed and secreted (RANTES) has been shown to be critical for its biological activity on leukocytes. Several N-terminus-modified CCL5/RANTES derivatives, such as N-Terminal truncated CCL5/RANTES, Met-RANTES, and amino-oxypentane (AOP)-RANTES exhibited antagonist or partial agonist functions when investigated on the properties of their receptors CCR1, CCR3, and CCR5. Studying 95 African samples from Cameroon, we found a naturally occurring variant of CCL5/RANTES containing a missense mutation located in the first amino acid of the secreted form (S24F). S24F binds CCR1, CCR3, and CCR5 and triggers receptor down-modulation comparable to CCL5/RANTES. Moreover, in CCR5 positive cells, S24F elicits cellular calcium mobilization equivalent to that obtained with CCL5/RANTES. By contrast, S24F does not provoke any response in CCR1 and CCR3 positive cells. As CCL5/RANTES is able to attract different subtypes of leukocytes into inflamed tissue and intervenes in a wide range of allergic and autoimmune diseases, the discovery of this natural N-terminus-modified CCL5/RANTES analogue exhibiting differential effects on CCL5/RANTES receptors, opens up additional perspectives for therapeutic intervention.

[Expressions of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 in chronic myeloid leukemia cells]

This study was aimed to explore the expression of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 in bcr/abl fusion gene positive CML cells, and to study the effects of P210(bcr/abl) fusion protein tyrosine kinase on expression of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 mRNAs in chronic myeloid leukemia cells. The expression levels of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 mRNA were detected by semi-quantitative RT-PCR in bcr/abl negative cells, bcr/abl positive cells, and P210(bcr/abl)-Rb-C-Box positive cells. The results showed that MIP-1alpha and CCR-1 mRNAs were expressed in bcr/abl negative cells, but not in positive cells. Both MCP-1 and CCR-2 mRNA cannot be detected in both bcr/abl positive and negative cells. After inhibiting P210(bcr/abl) tyrosine kinase activity by Rb-C-Box, expressions of MIP-1alpha and CCR-1 mRNAs were restored to normal (similar to P210(bcr/abl) negative cells). It is concluded that P210(bcr/abl) fusion protein inhibits the expression of MIP-1alpha and CCR-1 in chronic myeloid leukemia cells, but does not inhibit MCP-1 and CCR-2 mRNA expressions in these leukemia cells.

Deficiency in CCR5 but not CCR1 protects against neointima formation in atherosclerosis-prone mice: involvement of IL-10

The chemokine RANTES has been implicated in neointimal hyperplasia after arterial injury. We analyzed the differential role of the RANTES receptors CCR1 and CCR5 by genetic deletion in apolipoprotein E–deficient mice. Deficiency in CCR5 significantly reduced neointimal area after arterial wire injury, associated with a decrease in macrophages, CD3+ T lymphocytes, and CCR2+ cells. In contrast, CCR1 deficiency did not affect neointimal area or cell content. Deletion of CCR5 entailed an up-regulation of the anti-inflammatory cytokine interleukin 10 (IL-10) in neointimal smooth muscle cells, and its antibody blockade reversed effects in CCR5–/– mice. Conversely, proinflammatory interferon γ was increased in the neointima of CCR1–/– mice, and its blockade unmasked a reduction in macrophage recruitment. Our data indicate that CCR5 is more crucial than CCR1 for neointimal plaque formation, and that its attenuation in CCR5–/– mice is due to an atheroprotective immune response involving IL-10. This harbors important implications for targeting chemokine receptors in vascular remodeling.

A CCR1 antagonist prevents the development of experimental autoimmune myocarditis in association with T cell inactivation

Chemokines play an important role in induction of chemotaxis of immune cells. CCR1 is a chemokine receptor expressed on neutrophils, monocytes, and T lymphocytes. The role of CCR1 in immunity is not well examined. We demonstrated the role of CCR1 on T lymphocytes and the effect of a CCR1 antagonist, BX471 in myocarditis. Lewis rats were immunized with cardiac myosin on day 0 to establish experimental autoimmune myocarditis. Rats were then administered BX471 subcutaneously every day (group BX0: n = 7) or from day 14 (group BX14: n = 7) and were killed on day 21. We confirmed expression of CCR1 in cells infiltrating the myocardium by immunohistochemistry and FACS analysis. The development of myocarditis was almost completely prevented in group BX0, and myocarditis-affected areas were significantly decreased in size in group BX14. Cardiac function was markedly improved. Ribonuclease protection assay showed that the CCR1 antagonist treatment suppressed mRNA expression for IL-6, IL-1beta, and TNF-alpha in the hearts. An antigen-specific T cell proliferation assay was performed with CD4-positive T cells isolated from control rats immunized with cardiac myosin. T cell proliferation was inhibited by the CCR1 antagonist. Additionally, we showed by Western blot that the CCR1 antagonist suppressed ERK1/2 and JNK activities in T cells stimulated with myosin and that IL-2 reversed this suppression. The CCR1 antagonist reduced the severity of EAM by inhibiting cytokine expression and inducing T cell inactivation. Thus, the CCR1 antagonist may provide a novel therapeutic strategy treatment of myocarditis.

Differential regulation of CC chemokine receptors by 9-cis retinoic acid in the human mast cell line, HMC-1

Mast cells are well known as effector cells in a variety of inflammatory diseases, including asthma as well as other allergic disorders. The precise role of 9-cis retinoic acid (9CRA) in mast cells is not understood despite the accepted fact that 9CRA regulates inflammatory responses and neutrophil differentiation. In this study, we investigated the effects of 9CRA on the expression of CC chemokine receptors in the human mast cell line, HMC-1. 9CRA selectively inhibits the CCR2 mRNA level and increases the CCR3 mRNA level in both a time and dose dependent manner. Other CC chemokine receptors, including CCR1, CCR4 and CCR5 are not altered by treatment with 9CRA. Both TNF-alpha and LPS, known pro-inflammatory molecules, have no effect on mRNA levels of CC chemokine receptors. For surface expression, 9CRA decreased the CCR2 level but had no effect on the CCR3 level. 9CRA inhibited the chemotactic activity in response to the CCR2-dependent chemokine, MCP-1/CCL2 but not in response to CCR3-specific chemokine, eotaxin/CCL11. 9CRA decreased spontaneous homotype clustering. Therefore, our results demonstrate that 9CRA differentially decreases both CCR2 expression and chemotactic ability of HMC-1 cells, and may regulate the inflammatory effects of mast cells.

Essential contribution of a chemokine, CCL3, and its receptor, CCR1, to hepatocellular carcinoma progression

We previously observed that a chemokine, macrophage inflammatory protein-1 alpha/CCL3, and its receptor, CCR1, were aberrantly expressed in human hepatocellular carcinoma (HCC) tissues. Here, we show that CCL3 and CCR1 are also expressed in 2 different models of this cancer; N-nitrosodiethylamine (DEN)-induced HCC and HCC induced by hepatitis B virus surface (HBs) antigen-primed splenocyte transfer to myelo-ablated syngeneic HBs antigen transgenic mice. At 10 months after DEN treatment, foci number and sizes were remarkably reduced in CCR1- and CCL3-deficient mice, compared with those of wild-type (WT) mice, although tumor incidence were marginally, but significantly, higher in CCR1- and CCL3-deficient mice than in WT mice. Of note is that tumor angiogenesis was also markedly diminished in CCL3- and CCR1-deficient mice, with a concomitant reduction in the number of intratumoral Kupffer cells, a rich source of growth factors and matrix metalloproteinases (MMPs). Among growth factors and MMPs that we examined, only MMP9 and MMP13 gene expression was augmented progressively in liver of WT mice after DEN treatment. Moreover, MMP9, but not MMP13, gene expression was attenuated in CCR1- and CCL3-deficient mice, compared with that of WT mice. Furthermore, MMP9 was expressed mainly by mononuclear cells but not hepatoma cells, and MMP9-expressing cell numbers were decreased in CCR1- or CCL3-deficient mice, compared with WT mice. These observations suggest the contribution of the CCR1-CCL3 axis to HCC progression.