CCR5 delta32, matrix metalloproteinase-9 and disease activity in multiple sclerosis

Investigation of substituent effect of 1-(3,3-diphenylpropyl)-piperidinyl phenylacetamides on CCR5 binding affinity using QSAR and virtual screening techniques

A linear quantitative-structure activity relationship model is developed in this work using Multiple Linear Regression Analysis as applied to a series of 51 1-(3,3-diphenylpropyl)-piperidinyl phenylacetamides derivatives with CCR5 binding affinity. For the selection of the best variables the Elimination Selection-Stepwise Regression Method (ES-SWR) is utilized. The predictive ability of the model is evaluated against a set of 13 compounds. Based on the produced QSAR model and an analysis on the domain of its applicability, the effects of various structural modifications on biological activity are investigated. The study leads to a number of guanidine derivatives with significantly improved predicted activities.

CD26 + CD4 + T cell counts and attack risk in interferon-treated multiple sclerosis

Biomarkers that allow the identification of patients with multiple sclerosis (MS) with an insufficient response to immunomodulatory treatment would be desirable, as currently available treatments are only incompletely efficacious. Previous studies have shown that the expression of CD25, CD26 and CCR5 on T cells is altered in patients with active MS. We studied the expression of these molecules by flow cytometry in patients followed for six months during immunomodulatory treatment. In interferon (IFN)-beta-treated patients, we found that the hazard ratio for developing an attack was 28 in patients with CD26 + CD4 + T cell counts above median, and this risk was independent of the risk conferred by neutralizing anti-IFN-beta antibodies. CD26 + CD4 + T cell counts may identify patients with MS at increased risk of attack during treatment with IFN-beta.

The expression and function of chemokines involved in CNS inflammation

Chemokines and their receptors have principal roles in leukocyte trafficking under normal physiological and pathological conditions. The differential expression of the chemokine system in different parts of the CNS provides insights into the processes that are required for normal immune surveillance and pathological immune-mediated effector processes. Insights derived from studying multiple sclerosis, an inflammatory disorder of the CNS in humans, and experimental autoimmune encephalomyelitis, an animal model of this disorder, aid in further understanding the complexities of chemokine-mediated inflammation. Knowledge of the molecular biology of chemokines and their receptors, and the roles of specific chemokine ligands and receptors in the CNS in health and in disease have made these proteins targets for therapeutic intervention in neuroinflammation. We also discuss currently proposed and potentially useful chemokine receptor antagonists.

Variants of CCR5, which are permissive for HIV-1 infection, show distinct functional responses to CCL3, CCL4 and CCL5

CCR5 is one of the primary coreceptors for Env-mediated fusion between cells and human immunodeficiency virus type 1 (HIV-1). Analyses of CCR5 variants in cohorts of HIV-1 high-risk individuals led to the identification of multiple single amino-acid substitutions, which may have functional consequences. This study focused on eight naturally occurring allelic variants located between amino-acid residues 60 and 334 of CCR5. All studied allelic variants were highly expressed on the cell surface of HEK-293 cells and permissive for HIV-1 infection. Variant G301V showed 3.5-fold increase in 50% effective concentration (EC(50)) for CCL4 (MIP 1beta) in a competitive binding assay. There was also a significant reduction in CCL5 (RANTES) EC(50) for the R223Q, A335V and Y339F variants. The most unexpected functional abnormality was exhibited by the R60S variant that exhibited a loss of ligand-induced desensitization in chemotaxis assays, but showed normal CCL4 and CCL5 binding avidity. This mutation is located in the first intracellular loop, a domain that has not previously been shown to be involved in receptor desensitization. In conclusion, our results support earlier studies showing that these naturally occurring point mutations do not limit HIV-1 infection, and indicated that single amino-acid changes can have unexpected functional consequences.

Multiple sclerosis genetics: leaving no stone unturned

Compelling epidemiologic and molecular data indicate that genes play a primary role in determining who is at risk for developing multiple sclerosis (MS), how the disease progresses, and how someone responds to therapy. The genetic component of MS etiology is believed to result from the action of allelic variants in several genes. Their incomplete penetrance and moderate individual effect probably reflects epistatic interactions, post-transcriptional regulatory mechanisms, and significant environmental influences. Equally significant, it is also likely that locus heterogeneity exists, whereby specific genes influence susceptibility and pathogenesis in some individuals but not in others. With the aid of novel analytical algorithms, the combined study of genomic, transcriptional, proteomic, and phenotypic information in well-controlled study groups will define a useful conceptual model of pathogenesis and a framework for understanding the mechanisms of action of existing therapies for this disorder, as well as the rationale for novel curative strategies.

Modulators of the human CCR5 receptor. Part 2: SAR of substituted 1-(3,3-diphenylpropyl)-piperidinyl phenylacetamides

SAR and DMPK studies led to the identification of substituted N-alkyl-N-[1-(3,3-diphenylpropyl)piperidin-4-yl]-2-phenylacetamides as potent and orally bioavailable ligands for the human CCR5 chemokine receptor.

Transgenic mouse expressing human CCR5 as a model for in vivo assessments of human selective CCR5 antagonists

The species selectivity of receptor antagonists often hinders their preclinical assessment in vivo. In order to evaluate human selective CC chemokine receptor type 5 (CCR5) antagonists in vivo, we generated human CCR5 transgenic mice that expressed the transgene on both peripheral blood leukocytes as well as thymocytes. The selective CCR5 ligand CC chemokine ligand 4 (CCL4)/macrophage inflammatory protein (MIP)-1beta induced the chemotaxis of thymocytes that had been derived from the transgenic mice, but not from littermate mice, suggesting that the human CCR5 expressed in the transgenic mice were functional. The binding of the human CCR5 specific antibody 45531 to peripheral blood granulocytes from the transgenic mice was inhibited by human selective CCR5 antagonist SCH-351125. Using this antibody, we developed an ex vivo assay system that is suitable for the evaluation of a test compound's ability to occupy the human CCR5 receptor on mouse peripheral blood leukocytes. This transgenic mouse model is useful for estimating the pharmacodynamics of human selective CCR5 antagonists in vivo.

CCR5Delta32 polymorphism effects on CCR5 expression, patterns of immunopathology and disease course in multiple sclerosis

Four distinct patterns of tissue injury have been described in multiple sclerosis (MS) lesions. Infiltrating monocytes in lesions of all patterns co-express CCR1 and CCR5. However, in pattern II lesions, the number of CCR1 cells is decreased, while the number of CCR5 expressing cells is increased in late active versus early active regions. In contrast, CCR1 and CCR5 cells were equal in all regions of pattern III lesions. These suggest distinct inflammatory microenvironments in pattern II and III lesions and support MS pathological heterogeneity. A deletion in CCR5 (CCR5*Delta32), which encodes a truncated, non-functional protein, has been associated with late onset of MS and a favorable prognosis. We studied the association of CCR5*Delta32 with the course and severity of MS in 221 patients from a population-based cohort in Olmsted County, MN, and with patterns of immunopathology in 94 patients with biopsy-derived, pathologically confirmed demyelinating disease participating in the MS Lesion Project. The frequency of the genotypes in 221 patients from Olmsted County, MN, was 167 (75.6%) wild type, 52 (23.5%) heterozygotes, and 2 (0.9%) homozygotes. There was no association of carrier status for the CCR5*Delta32 mutation with disease severity as analyzed using the disease severity score (ranking of EDSS/duration stratified by duration), age of onset, gender or disease course (bout onset versus primary progressive). Due to low frequency of homozygotes no conclusion can be made regarding their relation to heterozygosity or wild-type status. The frequency of genotypes in the 94 biopsies was 77 (81.9%) wild type, 15 (16.0%) heterozygotes and 2 (2.1%) homozygotes. Carrier status for the CCR5*Delta32 mutation was not associated with patterns of immunopathology in MS. Despite similar numbers of T-lymphocytes, there were no CCR5+ T-cells nor was CCR5 expressed in the CNS of a homozygous CCR5*Delta32 MS patient, and heterozygous patients had reduced CCR5 expression compared to wild type patients. CCR5*Delta32 has a dose effect on CCR5 expression in the CNS, but is neither necessary for development of MS, nor CD3+ T cell recruitment into the CNS. Furthermore it does not segregate with patterns of immunopathology in MS. We did not find an association between CCR5*Delta32 mutation and disease severity and age of onset in MS.

The clinical potential of chemokine receptor antagonists

Chemokines belong to a family of chemotactic cytokines that direct the migration of immune cells towards sites of inflammation. They mediate their biological effects by binding to cell surface receptors, which belong to the G protein-coupled receptor superfamily. Since chemokines and their receptors have been implicated in the pathophysiology of a number of autoinflammatory diseases, chemokine receptor antagonists could prove to be useful therapeutics to target these diseases. Here, we review the role of chemokines in autoimmunity, concentrating mainly on the chemokine receptors CCR1 and CCR5, and discuss the potential utility of antagonists that target these 2 receptors as they progress through the clinic.

Decreased IgG production but increased MIP-1β expression in collagen-induced arthritis in C–C chemokine receptor 5-deficient mice

Collagen-induced arthritis (CIA) is a widely used model of human rheumatoid arthritis (RA) characterized by chronic inflammation of the synovial joints. The pathogenesis of RA and CIA has not been completely defined, but both involve the recruitment of leukocytes and lymphocytes to the joints and Th1-type cell mediated autoimmune responses. The C-C chemokine receptor 5 (CCR5) is preferentially expressed on Th1 cells and has been strongly implicated in inflammatory process through trafficking of leukocytes and lymphocytes into the sites of inflammation. We investigated the role of the CCR5 in CIA using CCR5 knockout mice (CCR5-/-) in which we analyzed the consequences of CCR5 deficiency for the immune response and inflammation. We found that CCR5-/- mice showed a significant reduction in the incidence of CIA after collagen II (CII)-immunization as compared to wild-type (CCR5+/+) mice. The reduced incidence seen in CCR5-/- mice was associated with these animals having significantly lower IgG levels, especially IgG2a and IgG2b antibodies against CII, as well as an obviously augmented IL-10 production in splenocytes. Overproduction of MIP-1beta in CCR5-deficient mice after CII-immunization may contribute partially to the occurrence of arthritis.

Involvement of beta-chemokines in the development of inflammatory demyelination

The importance of β-chemokines (or CC chemokine ligands – CCL) in the development of inflammatory lesions in the central nervous system of patients with multiple sclerosis and rodents with experimental allergic encephalomyelitis is strongly supported by descriptive studies and experimental models. Our recent genetic scans in families identified haplotypes in the genes of CCL2, CCL3 and CCL11-CCL8-CCL13 which showed association with multiple sclerosis. Complementing the genetic associations, we also detected a distinct regional expression regulation for CCL2, CCL7 and CCL8 in correlation with chronic inflammation in multiple sclerosis brains. These observations are in consensus with previous studies, and add new data to support the involvement of CCL2, CCL7, CCL8 and CCL3 in the development of inflammatory demyelination. Along with our own data, here we review the literature implicating CCLs and their receptors (CCRs) in multiple sclerosis and experimental allergic encephalomyelitis. The survey reflects that the field is in a rapid expansion, and highlights some of the pathways which might be suitable to pharmaceutical interventions.

Association of CCR5 delta32 deletion with early death in multiple sclerosis

PURPOSE

The interaction between chemokines and their receptors is extremely important in controlling T cell migration into sites of CNS inflammation. Because trafficking of inflammatory T cells into the central nervous system (CNS) is a key player in the pathogenesis of multiple sclerosis (MS), we investigated the possible association of CCR5 delta32 deletion in this disorder.

METHODS

DNA isolated from postmortem brain tissue samples of 132 patients with MS and from blood tissue samples of 163 gender and ethnicity-matched healthy controls was used to screen for the CCR5 delta32 deletion allele.

RESULTS

An increased frequency of 32-bp deletion allele was found to be associated with early death (P = 0.00005) and with a progressive reduction in the years of survival (onset to death). The death hazard ratio of CCR5 with deletion versus no deletion was 2.12, suggesting that MS patients with the 32-bp deletion have twice the mortality rate of patients with the normal genotype. This effect was more significant in females (hazard ratio 3.58).

CONCLUSION

A strong association of the CCR5delta32 deletion with early death could serve as a prognostic marker for MS.

CCR5-Delta32 mutation is strongly associated with primary sclerosing cholangitis

CCR5 plays a key role in the distribution of CD45RO+ T cells and contributes to generation of a T helper 1 immune response. CCR5-Delta32 is a 32-bp deletion associated with significant reduction in cell surface expression of the receptor. We investigated the role of CCR5-Delta32 on susceptibility to ulcerative colitis (UC), Crohn's disease (CD) and primary sclerosing cholangitis (PSC). Genotype and allelic association analyses were performed in 162 patients with UC, 131 with CD, 71 with PSC and 419 matched controls. There was a significant difference in CCR5 genotype (OR 2.27, P=0.003) between patients with sclerosing cholangitis and controls. Similarly, CCR5-Delta32 allele frequency was significantly higher in sclerosing cholangitis (17.6%) compared to controls (9.9%, OR 2.47, P=0.007) and inflammatory bowel disease patients without sclerosing cholangitis (11.3%, OR 1.9, P=0.027). There were no significant differences in CCR5 genotype or allele frequency between those with either UC or CD and controls. Genotypes with the CCR5-Delta32 variant were increased in patients with severe liver disease defined by portal hypertension and/or transplantation (45%) compared to those with mild liver disease (21%, OR 3.17, P=0.03). The CCR5-Delta32 mutation may influence disease susceptibility and severity in patients with PSC.

Chemokine receptors in the central nervous system: role in brain inflammation and neurodegenerative diseases

Chemokines were originally described as chemotactic cytokines involved in leukocyte trafficking. Research over the last decade, however, has shown that chemokine receptors are not restricted to leukocytes. In the brain, chemokine receptors are not only found in microglia (a brain macrophage), but also in astrocytes, oligodendrocytes and neurons. In this review, we describe the spatial and cellular distribution of chemokine receptors in the brain, distinguishing between constitutively and inducibly expressed receptors. We then discuss possible physiological functions, including neuronal migration, cell proliferation and synaptic activity. Evidence is emerging that chemokine receptors are also involved in neuronal death and hence neurodegenerative diseases. Chemokines may induce neuronal death either indirectly (e.g. through activation of microglia killing mechanisms) or directly through activation of neuronal chemokine receptors. Disease processes in which chemokines and their receptors are likely to be involved include multiple sclerosis (MS), Alzheimer's disease (AD), HIV-associated dementia (HAD) and cerebral ischemic disease. The study of chemokines and their receptors in the central nervous system (CNS) is not only relevant for the understanding of brain physiology and pathophysiology, but may also lead to the development of targeted treatments for neurodegenerative diseases.

Modulators of the human CCR5 receptor. Part 1: Discovery and initial SAR of 1-(3,3-diphenylpropyl)-piperidinyl amides and ureas

Investigation of weak screening hits led to the identification of N-alkyl-N-[1-(3,3-diphenylpropyl)piperidin-4-yl]-2-phenylacetamides and N-alkyl-N-[1-(3,3-diphenylpropyl)piperidin-4-yl]-N'-benzylureas as potent, selective ligands for the human CCR5 chemokine receptor.

MMP-9 microsatellite polymorphism and multiple sclerosis

A polymorphism (PM) in the microsatellite of the promoter region of matrix metalloproteinase 9 (MMP-9), modulating its expression, could play a role in susceptibility to multiple sclerosis (MS). MMP-9 PM was determined in 95 patients with MS (MS Group) and 95 age- and sex-matched controls (Control Group). Comparison of allelic frequencies showed that a higher number of CA repeats characterized the MS group (P<0.0001) and prevalence of carriers of > or =22 CA repeats was higher in the MS than in the Control Group (OR 3.4, 95% CI: 1.7-6.8, P<0.0001). An earlier age at disease onset was a characteristic of patients with >22 CA repeats (33+/-10 vs. 28+/-10, P=0.027). No differences were found in the main MRI parameters.

Influence of CCR5 delta32 polymorphism on multiple sclerosis susceptibility and disease course

The CCR5 chemokine receptor has been implicated in the pathogenesis of multiple sclerosis (MS). We carried out an allelic association study using a deletion polymorphism in the coding region of the CCR5 gene in 331 relapsing-remitting (RR) and secondary progressive (SP) MS patients, 108 primary progressive (PP) MS patients and 230 healthy controls. Of the 331 RR and SPMS patients, 172 were recruited from specialist clinics and 159 from a population survey. Disease severity was assessed clinically using the Expanded Disability Status Scale (EDSS) and used to calculate a progression index for each patient (defined as EDSS divided by duration of disease). No significant difference in distribution of the CCR5 delta32 allele was observed between the 331 RR/SPMS patients and controls, between the 108 PPMS patients and controls or between the PPMS and RR/SPMS groups. Furthermore, no differences in rate of disease progression were detected between carriers and noncarriers of the delta32 allele. In the population-based group of RR/SPMS patients, carriage of the CCR5 delta32 polymorphism was associated with a lower age at disease onset (mean age 26.562 versus 31.065 years, P = 0.003). However, no significant differences in age of onset were present in the PPMS group or in a second RRMS population. These results suggest that the CCR5 delta32 polymorphism is not a major determinant of susceptibility to develop MS in the population under study, and conflict with a previously reported association between CCR5 delta32 carriage and a better prognosis.

Expression of chemokine receptors CCR1 and CCR5 reflects differential activation of mononuclear phagocytes in pattern II and pattern III multiple sclerosis lesions

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the CNS. A recent study identified 4 patterns of demyelination in active MS lesions. The characteristics of pattern II lesions suggested a primary inflammatory mechanism of myelin injury, while pattern III lesions showed features consistent with dying-back oligodendrogliopathy. The recruitment, differentiation, and activation of mononuclear phagocytes are dependent on the expression of chemokine receptors. Using immunohistochemistry we quantified cellular expression of CCR1 and CCR5 in pattern II (n = 21) and pattern III (n = 17) lesion areas of differing demyelinating activity. Infiltrating monocytes in both lesion patterns co-expressed CCR1 and CCR5, suggesting conserved mechanisms of monocyte recruitment into the CNS. In pattern II lesions, the number of cells expressing CCR1 significantly decreased while CCR5 increased in late active compared with early active demyelinating regions. In striking contrast, numbers of cells expressing CCR1 and CCR5 were equal in all regions of pattern III lesions. As hypoxia-like mechanisms may play a role in pattern III lesions, we extended these studies to white matter infarcts (n = 7) in which the expression of CCR1 better resembled pattern III than pattern II lesions. As judged by mononuclear phagocyte chemokine receptor expression, there appear to be distinct tissue environments in pattern II and III MS lesions.

Cyclophosphamide modulates CD4+ T cells into a T helper type 2 phenotype and reverses increased IFN-γ production of CD8+ T cells in secondary progressive multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system considered to be mediated by T helper type-1 cells. Several agents have been found to modify the disease course of MS, including interferon-beta1 (IFN-beta1), glatiramer acetate mitoxantrone. We have employed pulse therapy with cyclophosphamide in a selected group of patients with actively progressive disease. Chemokine receptors have been found to differentiate between polarized T helper type-1 (Th1) and type-2 (Th2) lymphocytes. The chemokine receptors CCR5 and CXCR3 are expressed primarily on Th1 cells and CCR3, CCR4 and CCR8 on Th2 cells. Previous studies of the expression of chemokine receptors in MS have shown that active MS plaques are infiltrated by CCR5(+) and CXCR3(+) T cells. Some of these T cells may express both CCR5 and CXCR3. These T cells are major producers of IFN-gamma, which worsens the clinical condition of patients with MS. We previously found that patients with MS had a high proportion of CXCR3(+) T cells and that those with chronic progressive MS had a high proportion of CCR5(+) T cells in their peripheral blood. We report here that in patients with secondary progressive MS, cyclophosphamide induces a marked increase in the percentage of CCR4(+) T cells that produce high levels of IL-4 and reverses the increase in the percentages of IFN-gamma-producing CCR5(+) and CXCR3(+) CD8(+) T cells. Furthermore, therapy with cyclophosphamide increases IL-4-producing CD4(+) T cells and reverses the increase in IFN-gamma-producing CD8(+) T cells. Our study shows that cyclophosphamide has immunomodulatory properties besides its suppressive effects, and that chemokine receptors can be important tools both for understanding the immune dysregulation in MS and for monitoring response to therapy.

CCR5 expression influences the progression of human breast cancer in a p53-dependent manner

Chemokines are implicated in tumor pathogenesis, although it is unclear whether they affect human cancer progression positively or negatively. We found that activation of the chemokine receptor CCR5 regulates p53 transcriptional activity in breast cancer cells through pertussis toxin–, JAK2-, and p38 mitogen–activated protein kinase–dependent mechanisms. CCR5 blockade significantly enhanced proliferation of xenografts from tumor cells bearing wild-type p53, but did not affect proliferation of tumor xenografts bearing a p53 mutation. In parallel, data obtained in a primary breast cancer clinical series showed that disease-free survival was shorter in individuals bearing the CCR5Δ32 allele than in CCR5 wild-type patients, but only for those whose tumors expressed wild-type p53. These findings suggest that CCR5 activity influences human breast cancer progression in a p53-dependent manner.

Functional roles and therapeutic targeting of gelatinase B and chemokines in multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disease of the CNS of unknown cause. Pathogenetic mechanisms, such as chemotaxis, subsequent activation of autoreactive lymphocytes, and skewing of the extracellular proteinase balance, are targets for new therapies. Matrix metalloproteinase gelatinase B (MMP-9) is upregulated in MS and was recently shown to degrade interferon beta, one of the drugs used to treat MS. Consequently, the effect of endogenously produced interferon beta or parenterally given interferon beta may be increased by gelatinase B inhibitors. Blockage of chemotaxis or cell adhesion molecule engagement, and inhibition of hydroxymethyl-glutaryl-coenzyme-A reductase to lower expression of gelatinase B, may become effective treatments of MS, alone or in combination with interferon beta. This may allow interferon beta to be used at lower doses and prevent side-effects.

Promoter polymorphism of IL-10 and severity of multiple sclerosis

Functional polymorphisms of the genes for interleukin-10 (IL-10; promoter position -1082), chemokine receptor-5 (CCR5 32 bp deletion), tumor necrous factor-alpha (TNFalpha promoter position -308) and cytotoxic T-lymphocyte antigen-4 (CTLA-4 exon 1 position 49) were investigated for possible influence on susceptibility and outcome of multiple sclerosis (MS). The polymorphisms were typed by polymerase chain reaction based methods or by direct sequencing in MS patients (n=93-116) and controls (n=109-400). The studied genes were not associated with MS susceptibility. Patients were classified as suffering from a mild/moderate [Expanded Disability Status Scale (EDSS) 0-5.5] or severe (EDSS 6-8.0) form of MS. The AG genotype of IL-10 proved to be protective against severe MS in all patients (OR=0.32, P=0.010), the effect being increased over the years (10 years; OR=0.33, P=0.043, 15 years; OR=0.21, P=0.025 or 20 years; OR=0.14, P=0.026). Our results suggest that differential production of IL-10 might be a factor in the severity of MS.

[Chemokine--possible new options for the treatment of multiple sclerosis]

Accumulation and activation of mononuclear cells (lymphocytes and monocytes) in the CNS is one of the crucial steps in the pathogenesis of multiple sclerosis (MS). Chemokines and their receptors govern physiological and pathological leukocyte trafficking and may also be pertinent in hematogenous leukocyte infiltration of the CNS. Due to broad pharmacological interest in the chemokine system, peptide antagonists and small molecular antagonists are now available for clinical therapeutic trials. For the treatment of MS in particular, the chemokine receptors CCR1, CCR2, CCR5, and CXCR3 are possible targets in a chemokine-based therapeutic approach. In this review, we summarize current knowledge of the roles of chemokines and chemokine receptors in the pathogenesis of MS. Furthermore, options for possible therapeutic intervention through the chemokine system are outlined. Clinical studies in MS patients applying this knowledge are expected soon.

Chemokines and matrix metalloproteinase-9 in leukocyte recruitment to the central nervous system

Chemokines and matrix metalloproteinases (MMPs) play key roles in leukocyte migration across the blood-brain barrier (BBB) in infectious and inflammatory diseases, including multiple sclerosis (MS). In MS some chemokine receptors are expressed by an increased percentage of T cells in blood, the CSF concentration of chemokine ligands for these receptors is increased, and there is accumulation of T cells expressing relevant chemokine receptors in CSF and in the CNS parenchyma. Chemokine receptor expression patterns appear to reflect disease activity and disease stage in MS. MMPs are constitutively expressed or induced by proinflammatory cytokines and chemokines in leukocytes and CNS-resident cells. Several MMPs are expressed in MS plaques, and the CSF concentration of MMP-9 is increased in MS. The CSF concentration of MMP-9 may reflect disease activity in MS, and the CSF concentration of MMP-9 is higher in patients carrying the MS-associated HLA type DRB1 1501. We review how chemokines and MMP-9 may be involved in the pathogenesis of MS by controlling leukocyte migration between different functional compartments. Measuring expression of these molecules may find use as surrogate markers of disease activity in MS, and interfering with their function holds promise as a novel therapeutic strategy in MS.

Effects of the CCR5-Delta32 mutation on antiviral treatment in chronic hepatitis C

BACKGROUND/AIMS

The CC-chemokine receptor (CCR) 5-Delta32 mutation may predispose to chronic liver disease and high level viremia in hepatitis C. However, it is unclear whether CCR5-Delta32 also affects the response to antiviral treatment.

METHODS

We determined CCR5 genotypes in patients with hepatitis C treated with either interferon-alpha (N=78) or interferon and ribavirin (N=78). In each group, rates of end of treatment responses (ETRs) and sustained virological responses (SVRs) were compared between CCR5-Delta32 carriers and homozygous CCR5 wildtype patients.

RESULTS

ETR and SVR were achieved in 25 and 12 patients with interferon-alpha and in 52 and 45 patients with interferon/ribavirin treatment, respectively. CCR5-Delta32 carriers had significantly lower ETR rates than homozygous CCR5 wildtype patients (10.5 vs. 39.0%; P=0.02), whereas SVR rates only showed a non-significant trend (5.3 vs. 18.6%). Multivariate analysis confirmed CCR5-Delta32 carriage as an independent negative predictor for ETR in interferon-alpha monotherapy (odds ratio: 0.16; 95% confidence limits: 0.032-0.82; P=0.03). In interferon/ribavirin treated patients CCR-Delta32 carriers and CCR5 wildtype patients had similar ETR rates [19.2% vs. 23.1%] and SVR rates [20.0% vs. 21.2%].

CONCLUSIONS

Response rates to interferon-alpha monotherapy are reduced in hepatitis C virus (HCV)-infected patients carrying the CCR5-Delta32 mutation. However, interferon/ribavirin combination treatment may overcome this negative effect of CCR5-Delta32.

Native and transformed alpha2-macroglobulin in plasma from patients with multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease with unknown etiology. Various proteinases have been observed in increased levels in the central nervous system of patients with MS, which may contribute to the release of immunogenic myelin components. alpha2-Macroglobulin (alpha2M) inhibits a broad spectrum of proteinases sterically, undergoing major conformational changes induced by the proteinases themselves. Moreover, alpha2M acts as a carrier of several cytokines in the systemic circulation. By use of radial immunodiffusion, we determined the total alpha2M levels in plasma from 28 MS patients and 15 control subjects [14 patients with other neurologic diseases (OND) and one healthy individual]. No significant differences in total alpha2M concentration were observed between the MS patients and the control subjects. A comparison of the degree of alpha2M transformation in MS patients with different disease courses and controls was performed, using monoclonal antibodies (mAbs) specific for binding to native and transformed alpha2M, respectively. The fractions of transformed alpha2M were significantly increased in patients with secondary or primary progressive disease course compared with the controls. No significant differences were obtained using a native-specific mAb. At least a major proportion of alpha2M from the MS patients was able to change conformation from its native to its transformed state, as demonstrated by a shift in mAb reactivity, following methylamine treatment of the plasma samples. In conclusion, the results indicate that plasma alpha2M may be inactivated at a higher degree in patients with chronic progressive MS compared with patients with OND. This may influence the levels of proteinases and cytokines in the systemic circulation and may furthermore have diagnostic implications.

Common mutations in the familial Mediterranean fever gene associate with rapid progression to disability in non-Ashkenazi Jewish multiple sclerosis patients

Ancient founder mutations in the Mediterranean fever gene, MEFV, are associated with familial Mediterranean fever, a recessive, episodic, inflammatory disease. Since these mutations are reported to express with above normal levels of acute phase reactants in healthy heterozygotes we postulated that the heterozygous phenotype could aggravate the clinical expression of ongoing autoimmune diseases. This study evaluated progression to disability in relapsing-remitting multiple sclerosis (RR-MS) patients of non-Ashkenazi and Ashkenazi origin carrying an MEFV mutation, particularly the detrimental M694V, using the expanded disability status scale (EDSS). In the non-Ashkenazi patients group (n=48), carriers (n=17) presented with a two-fold higher fraction which reached EDSS=3.0 and 6.0 compared to noncarriers (n=31) despite a comparable mean of MS duration. The median time to reach EDSS=3.0 was 2 years in the carriers vs 10 years in noncarriers (P=0.007); The median time to reach EDSS=6.0 was 6 years vs 23 years, respectively (P=0.003). M694V heterozygous patients reached both EDSS milestones earlier than other patients. Progression to disability was not enhanced in Ashkenazi RR-MS carriers (n=12, noncarriers n=59). In conclusion, non-Asheknazi MS patients carrying one mutated MEFV gene, particularly M694V, expressed rapid progression to disability. The expressed mutation may increase inflammatory damage inflicted by autoimmune responses.

Evidence favoring the involvement of CC chemokine receptor (CCR) 5 in T-lymphocyte accumulation in optic neuritis

OBJECTIVE

To define the relationships between levels of chemokine receptor (CCR)5+ T-cells in blood and cerebrospinal fluid (CSF) of optic neuritis (ON) and control patients (CON).

MATERIALS AND METHODS

Expression of CCR5 and related receptors CCR1 and CCR3 on CD4- and CD8-positive T-cells in peripheral blood mononuclear cells (PBMC) and CSF was determined by flow cytometry in 20 patients with ON, 16 control patients with lumbar spondylosis, 20 healthy controls (HC) and 16 patients with rheumatoid arthritis (RA).

RESULTS

CCR5+CD4+ and CD8+ T-cells were enriched in CSF, compared with PBMC, in both ON and CON patients (all P < 0.001), and the percentages of CD4+/CCR5+ (r = 0.917) and CD8+/CCR5+ (r = 0.828) cells in PBMC and CSF were strongly and directly correlated. CCR5+ T-cells produce high amounts of tumor necrosis factor-alpha (TNF-alpha) and very low amounts of interleukin-5 (IL-5). Closely related receptors (CCR1, CCR3) were not altered.

CONCLUSIONS

Our data suggest an involvement of CCR5 in T-cell accumulation in the inflamed central nervous system.

Longitudinal study of chemokine receptor expression on peripheral lymphocytes in multiple sclerosis: CXCR3 upregulation is associated with relapse

The interaction between chemokines and their receptors leads to selective recruitment of cells to foci of inflammation. Cross-sectional studies have reported significantly different expression of chemokine receptors CXCR3, CCR5 and CCR2 on peripheral blood lymphocytes in multiple sclerosis (MS) compared with controls. Cells expressing these receptors are likely to play a pathogenic role as suggested by studies of experimental autoimmune encephalomyelitis. Also, immunogenetic studies of nonfunctional CCR5 receptors in MS patients, due to 32delta deletion, demonstrated a delay in time to next relapse. The aims of this study were to detect any changes in the serial expression of chemokine receptors CCR2, CCR3, CCR5 and CXCR3 on peripheral blood CD4+ lymphocytes from patients with MS and to correlate the changes with relapses. Upregulation of CXCR3 expression on peripheral blood CD4+ lymphocytes was associated with all relapses and CCR5 expression was significantly affected with all relapses. Clinical recovery, with or without intravenous methylprednisolone treatment, coincided with the return of CXCR3 towards baseline in all but one case. Fluctuation in the expression of CXCR3 and CCR5 was also significantly greater in clinically stable patients with MS compared with controls, which may be due to subclinical disease activity. These findings provide further support for the view that CXCR3 and CCR5 antagonists could have a therapeutic value in MS.

NFkappaB and AP-1 DNA binding activity in patients with multiple sclerosis

Current evidence suggests that multiple sclerosis (MS) results from an autoimmune response mediated by T lymphocytes, which would be activated in the peripheral blood and migrate into the central nervous system. NFkappaB and AP-1 are two main transcription factors involved in T-cell activation. To investigate possible alterations in the activity of these factors in MS individuals, we have assayed NFkappaB and AP-1 DNA binding activity in peripheral blood mononuclear cells (PBMC). Binding activity was analyzed by gel mobility shift assay in MS patients compared with controls. No significant differences were found between the two groups, indicating no evidence of abnormalities associated with MS in NFkappaB or AP-1 binding activities in PBMC, both basally and after PMA+anti-CD3 antibody induction.

The role of MCP-1 (CCL2) and CCR2 in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE)

Multiple sclerosis (MS) is the commonest inflammatory demyelinating disease of the human central nervous system (CNS). In MS, CNS inflammation is associated with demyelination and axonal degeneration, which leads to clinical presentation. Expression and cellular localization of CCL2/MCP-1 and CCR2 in MS have been described in the three compartments: brain, cerebrospinal fluid (CSF) and blood. Evidence from descriptive, transgenic, knockout and neutralizing studies of experimental autoimmune encephalomyelitis (EAE) points towards a nonredundant role of CCL2 and CCR2 in the recruitment of inflammatory infiltrate into the CNS. Hence, CCL2 and CCR2 may be targets for specific and effective treatment in MS.

Functional expression of chemokine receptor CCR5 on CD4(+) T cells during virus-induced central nervous system disease

Intracranial infection of C57BL/6 mice with mouse hepatitis virus (MHV) results in an acute encephalomyelitis followed by a demyelinating disease similar in pathology to the human disease multiple sclerosis (MS). CD4(+) T cells are important in amplifying demyelination by attracting macrophages into the central nervous system (CNS) following viral infection; however, the mechanisms governing the entry of these cells into the CNS are poorly understood. The role of chemokine receptor CCR5 in trafficking of virus-specific CD4(+) T cells into the CNS of MHV-infected mice was investigated. CD4(+) T cells from immunized CCR5(+/+) and CCR5(-/-) mice were expanded in the presence of the immunodominant epitope present in the MHV transmembrane (M) protein encompassing amino acids 133 to 147 (M133-147). Adoptive transfer of CCR5(+/+)-derived CD4(+) T cells to MHV-infected RAG1(-/-) mice resulted in CD4(+)-T-cell entry into the CNS and clearance of virus from the brain. These mice also displayed robust demyelination correlating with macrophage accumulation within the CNS. Conversely, CD4(+) T cells from CCR5(-/-) mice displayed an impaired ability to traffic into the CNS of MHV-infected RAG1(-/-) recipients, which correlated with increased viral titers, diminished macrophage accumulation, and limited demyelination. Analysis of chemokine receptor mRNA expression by M133-147-expanded CCR5(-/-)-derived CD4(+) T cells revealed reduced expression of CCR1, CCR2, and CXCR3, indicating that CCR5 signaling is important in increased expression of these receptors, which aid in trafficking of CD4(+) T cells into the CNS. Collectively these results demonstrate that CCR5 signaling is important to migration of CD4(+) T cells to the CNS following MHV infection.

Frequencies of the G-protein beta3 subunit C825T polymorphism and the delta 32 mutation of the chemokine receptor-5 in patients with multiple sclerosis

In the pathogenesis of multiple sclerosis (MS) genetic factors are known to influence autoreactive T-cell-actions like proliferation and chemotaxis across the blood-brain barrier via chemokine receptors (CCR) and G-protein coupled activating mechanisms. For the first time, we studied the frequencies of a recently described C825T polymorphism in the G-protein encoding gene for the beta3 subunit (GNB3) together with frequencies of a 32-base-pair deletion in the CCR5 gene (delta32 CCR5) in patients with MS (n = 253: relapsing-remitting (RR), n = 124 and chronic progressive course, n = 129). Apart from a trend to a reduced frequency of delta32 CCR5 and increased GNB3 825T polymorphism in primary chronic progressive patients, numbers did not reach statistical significance in any group of MS. These results could not support differences in the genetic background of MS based on that CCR5 mutation or the described GNB3 polymorphism.

Balanced polymorphism selected by genetic versus infectious human disease

The polymorphisms within the human genome include several functional variants that cause debilitating inherited diseases. An elevated frequency of some of these deleterious mutations can be explained by a beneficial effect that confers a selective advantage owing to disease resistance in carriers of such mutations during an infectious disease outbreak. We here review plausible examples of balanced functional polymorphisms and their roles in the defense against pathogens. The genome organization of the chemokine receptor and HLA gene clusters and their influence on the HIV/AIDS epidemic provides compelling evidence for the interaction of infectious and genetic diseases in recent human history.

Chemokine receptor expression on T cells is related to new lesion development in multiple sclerosis

The expression of chemokine receptors CCR5 and CXCR3 on CD4 and CD8 positive T cells in blood, measured by flow cytometry, was studied in 124 patients with different clinical subtypes of multiple sclerosis (MS) and 22 healthy controls. In a subgroup of patients (n=69) from whom MRI was available, chemokine receptor expression was correlated to the annualised changes in T1 and T2 lesion load. It was found that CCR5 and CXCR3 on both cell types might have impact on annualised increase in T2 lesion load, but not on T1 lesion load. Our results suggest that chemokines may play a more important role in the development of new lesions in MS than in the long-term outcome of those lesions.

Chemokine receptor antagonism as an approach to anti-inflammatory therapy: 'just right' or plain wrong?

Inflammation plays a pivotal role in exacerbating a wide array of human diseases. The chemokines are a group of proteins that control the movement and activation of the immune cells involved in all aspects of the inflammatory response. Recently, their cognate receptors have attracted considerable interest as therapeutic targets, in part because they are G-protein-coupled receptors, which have been antagonized successfully before by the pharmaceutical industry. Indeed, several companies have now reported the development of selective small-molecule chemokine receptor antagonists, and some of these compounds have even entered human Phase I clinical trials. Preclinical studies of the responsiveness of murine models of inflammation to either pharmacologic or genetic intervention have suggested that antagonism of some chemokine receptors may well prove to be a safe and efficacious approach to anti-inflammatory therapy.

Treatment of experimental autoimmune encephalomyelitis with the chemokine receptor antagonist Met-RANTES

Specific chemokines and chemokine receptors have been implicated in inflammatory demyelinating diseases of the central nervous system (CNS), including multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). Amino-terminal modifications of chemokines can alter receptor interactions, converting agonists to specific antagonists. To examine the function in EAE of murine types 1 and 5 CC chemokine receptors (CCR1 and CCR5), we used Met-RANTES, a peptide that blocks both receptors; controls received heat-inactivated peptide. There was no effect of active treatment on acute-monophasic EAE, regardless whether compound was given at onset or in a pre-treatment regimen. Administered at disease onset, Met-RANTES modestly but significantly ameliorated fixed neurological disability at the endpoint of chronic-relapsing EAE. Met-RANTES treatment did not reduce CNS cellular infiltrates or up-regulation of CCR1 and CCR5 in affected CNS tissues. Analysis of a subset of mice suggested a trend towards reduced axonal pathology in those receiving active treatment. These data indicate that chemokine receptor blockade with Met-RANTES does not affect leukocyte trafficking in chronic-relapsing EAE. Further analysis of the effects of chemokine receptor blockade may need to focus on leukocyte activation within the affected CNS as well as trafficking events.

Interferon-beta treatment alters peripheral blood monocytes chemokine production in MS patients

Chemokines direct the recruitment of leukocytes to inflammatory sites and may also participate in the regulation of cytokine production by naive T helper cells. Chemokine production by blood monocytes was investigated by intracytoplasmic staining in interferon-beta (IFN-beta)-treated multiple sclerosis (MS) patients, untreated MS patients, and healthy controls. Under unstimulated conditions, no differences in the production of interleukin-8 (IL-8), IFN-inducible protein 10 (IP-10), monokine induced by interferon-gamma (Mig), monocyte chemoattractant protein-1 (MCP-1), and monocyte chemoattractant protein-3 (MCP-3) were seen between untreated MS patients and controls. Chemokine production by monocytes following T cell activation was decreased in MS patients taking IFN-beta compared to controls and untreated MS patients. Unlike other chemokines, macrophage inflammatory protein-1alpha (MIP-1alpha) production by monocytes was significantly decreased in untreated MS patients compared to controls, and IFN-beta treatment increased MIP-1alpha expression to the level seen in controls. In vitro addition of IFN-beta1b to peripheral blood mononuclear cells (PBMC) cultures tended to decrease the production of IL-8, IP-10, Mig, MCP-1, and MCP-3, but not of MIP-1alpha. These findings suggest that IFN-beta treatment may have a differential affect on chemokine production by monocytes. Longitudinal studies must be done to confirm these observations.

Clinical overview of leukocyte adhesion and migration: where are we now?

This article discusses the potential for clinical translation of the large amount of information on the molecular basis of leukocyte-endothelial cell interactions that has been collected over the last twenty years. Areas of current interest include the identification of adhesion molecule expression in inflammation by diagnostic imaging, understanding variability in inflammatory responsiveness and disease susceptibility through identification of adhesion molecule and chemokine polymorphisms and the application to the treatment of inflammatory diseases of monoclonal antibodies and conventional drugs with specific actions on leukocyte adhesion and migration.

Selective suppression of chemokine receptor CXCR3 expression by interferon-beta1a in multiple sclerosis

We studied the expression of chemokine receptors CCR1, CCR2, CCR3, CCR5, and CXCR3 on CD4 and CD8 positive T cells, and on CD14 positive monocytes in blood from 10 patients with relapsing-remitting multiple sclerosis (MS) at initiation of interferon (IFN)-beta treatment, after 1 month and after 3 months of treatment. It was found that the expression of CXCR3 on CD4+ and CD8+ T cells was significantly reduced after 3 months of treatment. The expression of other receptors was unaltered. Since CXCR3 cells are enriched in cerebrospinal fluid (CSF), and are detected in lesion material in MS this may represent an important mode of action of interferon-beta in MS.

Chemokine receptor expression on B cells and effect of interferon-beta in multiple sclerosis

We investigated the B-cell expression of chemokine receptors CXCR3, CXCR5 and CCR5 in the blood and cerebrospinal fluid (CSF) from patients in relapse of multiple sclerosis (MS) and in neurological controls. Chemokine receptor expression was also studied in interferon-beta-treated patients with relapsing-remitting or secondary progressive MS. We observed significantly higher expression of CXCR3 on B cells in the CSF in active MS than in controls. Patients with active MS also had higher B-cell expression of CCR5 in blood. No major differences between RRMS and SPMS patients were detected, and chemokine receptor expression was not affected by interferon-beta treatment.

Chemokine receptors: multifaceted therapeutic targets

Chemokines and their receptors are involved in the pathogenesis of diseases ranging from asthma to AIDS. Chemokine receptors are G-protein-coupled serpentine receptors that present attractive tractable targets for the pharmaceutical industry. It is only ten years since the first chemokine receptor was discovered, and the rapidly expanding number of antagonists holds promise for new medicines to combat diseases that are currently incurable. Here, I focus on the rationale for developing antagonists of chemokine receptors for inflammatory disorders and AIDS, and the accumulating evidence that favours this strategy despite the apparent redundancy in the chemokine system.

Chemokines in autoimmune disease

Growing evidence indicates that structural cells play a crucial role in the chronic inflammation of autoimmunity by their recruitment of chemokine-dependent cells. Members of the two functional classes of chemokines, inflammatory and homeostatic, seem to be involved in lymphocyte recruitment and survival, and in establishing ectopic lymphoid structures in the target organs of autoimmune diseases. Results from animal models suggest that chemokines are reasonable therapeutic targets in autoimmunity.

CCR1+/CCR5+ mononuclear phagocytes accumulate in the central nervous system of patients with multiple sclerosis

Mononuclear phagocytes (monocytes, macrophages, and microglia) are considered central to multiple sclerosis (MS) pathogenesis. Molecular cues that mediate mononuclear phagocyte accumulation and activation in the central nervous system (CNS) of MS patients may include chemokines RANTES/CCL5 and macrophage inflammatory protein-1alpha/CCL3. We analyzed expression of CCR1 and CCR5, the monocyte receptors for these chemokines, on circulating and cerebrospinal fluid CD14+ cells, and in MS brain lesions. Approximately 70% of cerebrospinal fluid monocytes were CCR1+/CCR5+, regardless of the presence of CNS pathology, compared to less than 20% of circulating monocytes. In active MS lesions CCR1+/CCR5+ monocytes were found in perivascular cell cuffs and at the demyelinating edges of evolving lesions. Mononuclear phagocytes in early demyelinating stages comprised CCR1+/CCR5+ hematogenous monocytes and CCR1-/CCR5- resident microglial cells. In later stages, phagocytic macrophages were uniformly CCR1-/CCR5+. Cultured in vitro, adherent monocytes/macrophages up-regulated CCR5 and down-regulated CCR1 expression, compared to freshly-isolated monocytes. Taken together, these findings suggest that monocytes competent to enter the CNS compartment derive from a minority CCR1+/CCR5+ population in the circulating pool. In the presence of ligand, these cells will be retained in the CNS. During further activation in lesions, infiltrating monocytes down-regulate CCR1 but not CCR5, whereas microglia up-regulate CCR5.