Chemokine Receptor 5 Antagonists Research Articles

A novel small-molecular CCR5 antagonist promotes neural repair after stroke.

Chemokine receptor 5 (CCR5) is one of the main co-receptors of HIV-1, and has been found to be a potential therapeutic target for stroke. Maraviroc is a classic CCR5 antagonist, which is undergoing clinical trials against stroke. As maraviroc shows poor blood-brain barrier (BBB) permeability, it is of interest to find novel CCR5 antagonists suitable for neurological medication. In this study we characterized the therapeutic potential of a novel CCR5 antagonist A14 in treating ischemic stroke mice. A14 was discovered in screening millions compounds in the Chemdiv library based on the molecular docking diagram of CCR5 and maraviroc. We found that A14 dose-dependently inhibited the CCR5 activity with an IC50 value of 4.29 μM. Pharmacodynamic studies showed that A14 treatment exerted protective effects against neuronal ischemic injury both in vitro and vivo. In a SH-SY5Y cell line overexpressing CCR5, A14 (0.1, 1 μM) significantly alleviated OGD/R-induced cell injury. We found that the expression of CCR5 and its ligand CKLF1 was significantly upregulated during both acute and recovery period in focal cortical stroke mice; oral administration of A14 (20 mg·kg-1·d-1, for 1 week) produced sustained protective effect against motor impairment. A14 treatment had earlier onset time, lower onset dosage and much better BBB permeability compared to maraviroc. MRI analysis also showed that A14 treatment significantly reduced the infarction volume after 1 week of treatment. We further revealed that A14 treatment blocked the protein-protein interaction between CCR5 and CKLF1, increasing the activity of CREB signaling pathway in neurons, thereby improving axonal sprouting and synaptic density after stroke. In addition, A14 treatment remarkably inhibited the reactive proliferation of glial cells after stroke and reduced the infiltration of peripheral immune cells. These results demonstrate that A14 is a promising novel CCR5 antagonist for promoting neuronal repair after ischemic stroke. A14 blocked the protein-protein interaction between CKLF1 and CCR5 after stroke by binding with CCR5 stably, improved the infarct area and promoted motor recovery through reversing the CREB/pCREB signaling which was inhibited by activated CCR5 Gαi pathway, and benefited to the dendritic spines and axons sprouting.

Intramyocardial injected human umbilical cord-derived mesenchymal stem cells (HucMSCs) contribute to the recovery of cardiac function and the migration of CD4+ T cells into the infarcted heart via CCL5/CCR5 signaling

BackgroundHuman umbilical cord-derived mesenchymal stem cells (HucMSCs) have been recognized as a promising cell for treating myocardial infarction (MI). Inflammatory response post MI is critical in determining the cardiac function and subsequent adverse left ventricular remodeling. However, the local inflammatory effect of HucMSCs after intramyocardial injection in murine remains unclear.MethodsHucMSCs were cultured and transplanted into the mice after MI surgery. Cardiac function of mice were analyzed among MI-N.S, MI-HucMSC and MI-HucMSC-C–C Motif Chemokine receptor 5 (CCR5) antagonist groups, and angiogenesis, fibrosis and hypertrophy, and immune cells infiltration of murine hearts were evaluated between MI-N.S and MI-HucMSC groups. We detected the expression of inflammatory cytokines and their effects on CD4+ T cells migration.ResultsHucMSCs treatment can significantly improve the cardiac function and some cells can survive at least 28 days after MI. Intramyocardial administration of HucMSCs also improved angiogenesis and alleviated cardiac fibrosis and hypertrophy. Moreover, we found the much higher numbers of CD4+ T cells and CD4+FoxP3+ regulatory T cells (Tregs) in the heart with HucMSCs than that with N.S treatment on day 7 post MI. In addition, the protein level of C–C Motif Chemokine Ligand 5 (CCL5) greatly increased in HucMSCs treated heart compared to MI-N.S group. In vitro, HucMSCs inhibited CD4+ T cells migration and addition of CCL5 antibody or CCR5 antagonist significantly reversed this effect. In vivo results further showed that addition of CCR5 antagonist can reduce the cardioprotective effect of HucMSCs administration on day 7 post MI injury.ConclusionThese findings indicated that HucMSCs contributed to cardiac functional recovery and attenuated cardiac remodeling post MI. Intramyocardial injection of HucMSCs upregulated the CD4+FoxP3+ Tregs and contributed to the migration of CD4+ T cells into the injured heart via CCL5/CCR5 pathway.

Inhibition of inflammatory cell infiltration by antagonistic peptides that specifically bind to CCR5 via regulation of the NF-kappa B signaling pathway in rats with colitis

IntroductionCC chemokine receptor 5 (CCR5) and the NF-κB signaling pathway play important roles in the pathophysiology of inflammatory bowel disease (IBD). Previously, we synthesized two peptides (GH and HY peptides) that specifically bind to the first and the second extracellular loops (ECL1 and ECL2, respectively) of CCR5 and preliminarily found an inhibitory effect of these peptides on colitis. However, the specific mechanism by which these two peptides regulate trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats remains unclear.Material and methodsExperimental colitis was induced by 5% TNBS. CCR5 antagonist peptides were administered intravenously once a day for a week. Histological evaluation, real-time PCR, western blotting and correlation analysis were performed to examine the effects of the CCR5 binding peptides on the infiltration of inflammatory cells and the NF-κB signaling pathway.ResultsGH and HY peptides ameliorated mucosal damage and reduced the infiltration of neutrophils, lymphocytes and macrophages in experimental colitis (P < 0.05). The expression of NF-κB-related genes, including p105, p100, IKK and TNF-α, was reduced after GH and HY peptide administration (P < 0.01), and the protein level of TNF-α and the phosphorylation of IKK, IκBα and p65 were also suppressed. Furthermore, CCR5 antagonist peptides inhibited nuclear translocation of p65. Spearman correlation analysis showed that the infiltration of inflammatory cells was significantly correlated with the NF-κB pathway.ConclusionsAntagonistic peptides that specifically bind to ECL1 and ECL2 of CCR5 inhibit the infiltration of neutrophils, lymphocytes and macrophages in the colonic mucosa of SD rats with TNBS-induced colitis via regulation of the NF-κB signaling pathway.

CC Chemokine Receptor 5 Targeted Nanoparticles Imaging the Progression and Regression of Atherosclerosis Using Positron Emission Tomography/Computed Tomography.

Chemokines and chemokine receptors play an important role in the initiation and progression of atherosclerosis by mediating the trafficking of inflammatory cells. Chemokine receptor 5 (CCR5) has major implications in promoting the development of plaques to advanced stage and related vulnerability. CCR5 antagonist has demonstrated the effective inhibition of atherosclerotic progression in mice, making it a potential biomarker for atherosclerosis management. To accurately determine CCR5 in vivo, we synthesized CCR5 targeted Comb nanoparticles through a modular design and construction strategy with control over the physiochemical properties and functionalization of CCR5 targeting peptide d-Ala-peptide T-amide (DAPTA-Comb). In vivo pharmacokinetic evaluation through 64Cu radiolabeling showed extended blood circulation of 64Cu-DAPTA-Combs conjugated with 10%, 25%, and 40% DAPTA. The different organ distribution profiles of the three nanoparticles demonstrated the effect of DAPTA on not only physicochemical properties but also targeting efficiency. In vivo positron emission tomography/computed tomography (PET/CT) imaging in an apolipoprotein E knockout mouse atherosclerosis model (ApoE-/-) showed that the three 64Cu-DAPTA-Combs could sensitively and specifically detect CCR5 along the progression of atherosclerotic lesions. In an ApoE-encoding adenoviral vector (AAV) induced plaque regression ApoE-/- mouse model, decreased monocyte recruitment, CD68+ macrophages, CCR5 expression, and plaque size were all associated with reduced PET signals, which not only further confirmed the targeting efficiency of 64Cu-DAPTA-Combs but also highlighted the potential of these targeted nanoparticles for atherosclerosis imaging. Moreover, the up-regulation of CCR5 and colocalization with CD68+ macrophages in the necrotic core of ex vivo human plaque specimens warrant further investigation for atherosclerosis prognosis.

3D-QSAR Studies on the Biological Activity of Imidazolidinylpiperidinylbenzoic Acids as Chemokine Receptor Antagonists.

Human immunodeficiency virus type 1 (HIV-1) infection ultimately leading to acquired immunodeficiency syndrome (AIDS), remains a significant problem. CCR5 is a member of the chemokine receptor family that is utilized in the early stage of the replication cycle by the most commonly transmitted M-tropic strains of HIV-1. In this study, we developed 3D-QSAR models using CoMFA and CoMSIA methods on a series of 71 imidazolidinylpiperidinylbenzoic acid CCR5 antagonists, in order to better understand the substituent requirements and get more potent antagonists of CCR5. The research of 3D-QSAR modeling of imidazolidinylpiperidinylbenzoic acids as chemokine receptor 5 (CCR5) antagonists was conducted using comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA). For this study, a dataset containing 71 imidazolidinyl-piperidinyl-benzoic acids was divided into a training set of 22 compounds and a test set of 49 compounds. The results obtained from the CoMFA/CoMSIA model exhibited a statistical significance r(2) of 0.996 (0.984) with an estimated standard error of 0.109 (0.209). Both CoMFA and CoMSIA models provided valuable insight into the structural requirements for improving the activity of then CCR5 antagonists.

Combined 3D-QSAR modeling and molecular docking study on azacycles CCR5 antagonists

The beta chemokine receptor 5 (CCR5) is an attractive target for pharmaceutical industry in the HIV-1, inflammation and cancer therapeutic areas. In this study, we have developed quantitative structure activity relationship (QSAR) models for a series of 41 azacycles CCR5 antagonists using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and Topomer CoMFA methods. The cross-validated coefficient q2 values of 3D-QASR (CoMFA, CoMSIA, and Topomer CoMFA) methods were 0.630, 0.758, and 0.852, respectively, the non-cross-validated R2 values were 0.979, 0.978, and 0.990, respectively. Docking studies were also employed to determine the most probable binding mode. 3D contour maps and docking results suggested that bulky groups and electron-withdrawing groups on the core part would decrease antiviral activity. Furthermore, docking results indicated that H-bonds and π bonds were favorable for antiviral activities. Finally, a set of novel derivatives with predicted activities were designed.

Computational modeling of human coreceptor CCR5 antagonist as a HIV-1 entry inhibitor: using an integrated homology modeling, docking, and membrane molecular dynamics simulation analysis approach

Chemokine receptor 5 (CCR5) is an integral membrane protein that is utilized during human immunodeficiency virus type-1 entry into host cells. CCR5 is a G-protein coupled receptor that contains seven transmembrane (TM) helices. However, the crystal structure of CCR5 has not been reported. A homology model of CCR5 was developed based on the recently reported CXCR4 structure as template. Automated docking of the most potent (14), medium potent (37), and least potent (25) CCR5 antagonists was performed using the CCR5 model. To characterize the mechanism responsible for the interactions between ligands (14, 25, and 37) and CCR5, membrane molecular dynamic (MD) simulations were performed. The position and orientation of ligands (14, 25, and 37) were found to be changed after MD simulations, which demonstrated the ability of this technique to identify binding modes. Furthermore, at the end of simulation, it was found that residues identified by docking were changed and some new residues were introduced in the proximity of ligands. Our results are in line with the majority of previous mutational reports. These results show that hydrophobicity is the determining factor of CCR5 antagonism. In addition, salt bridging and hydrogen bond contacts between ligands (14, 25, and 37) and CCR5 are also crucial for inhibitory activity. The residues newly identified by MD simulation are Ser160, Phe166, Ser180, His181, and Trp190, and so far no site-directed mutagenesis studies have been reported. To determine the contributions made by these residues, additional mutational studies are suggested. We propose a general binding mode for these derivatives based on the MD simulation results of higher (14), medium (37), and lower (25) potent inhibitors. Interestingly, we found some trend for these inhibitors such as, salt bridge interaction between basic nitrogen of ligand and acidic Glu283 seemed necessary for inhibitory activity. Also, two aromatic pockets (pocket I – TM1-3 and pocket II – TM3-6) were linked by the central polar region in TM7, and the simulated inhibitors show important interactions with the Trp86, Tyr89, Tyr108, Phe112, Ile198, Tyr251, Leu255, and Gln280 and Glu283 residues. These results shed light on the usage of MD simulation to identify more stable, optimal binding modes of the inhibitors.

Maraviroc, a chemokine receptor-5 antagonist, fails to demonstrate efficacy in the treatment of patients with rheumatoid arthritis in a randomized, double-blind placebo-controlled trial

IntroductionThe purpose of this study was to determine whether maraviroc, a human CC chemokine receptor 5 (CCR5) antagonist, is safe and effective in the treatment of active rheumatoid arthritis (RA) in patients on background methotrexate (MTX).MethodsThis phase IIa study comprised two distinct components: an open-label safety study of the pharmacokinetics (PK) of MTX in the presence of maraviroc, and a randomized, double-blind, placebo-controlled, proof-of-concept (POC) component. In the PK component, patients were randomized 1:1 to receive maraviroc 150 or 300 mg twice daily (BID) for four weeks. In the POC component, patients were randomized 2:1 to receive maraviroc 300 mg BID or placebo for 12 weeks. Patients were not eligible for inclusion in both components.ResultsSixteen patients were treated in the safety/PK component. Maraviroc was well tolerated and there was no evidence of drug-drug interaction with MTX. One hundred ten patients were treated in the POC component. The study was terminated after the planned interim futility analysis due to lack of efficacy, at which time 59 patients (38 maraviroc; 21 placebo) had completed their week 12 visit. There was no significant difference in the number of ACR20 responders between the maraviroc (23.7%) and placebo (23.8%) groups (treatment difference -0.13%; 90% CI -20.45, 17.70; P = 0.504). The most common all-causality treatment-emergent adverse events in the maraviroc group were constipation (7.8%), nausea (5.2%), and fatigue (3.9%).ConclusionsMaraviroc was generally well tolerated over 12 weeks; however, selective antagonism of CCR5 with maraviroc 300 mg BID failed to improve signs and symptoms in patients with active RA on background MTX.Trial RegistrationClinicalTrials.gov: NCT00427934

Immunotherapies in HIV-1 infection

The purpose of this review is to describe the current status of immunotherapies for the treatment of HIV-1 infection. This review is timely, as the results of the phase III clinical trials of recombinant interleukin-2 (rIL-2) as adjuncts to combination antiretroviral therapy are about to be released. For many years, the use of rIL-2 in HIV-infected individuals has been explored. Although the results of the clinical endpoint studies of rIL-2 are awaited, there are now further data for rIL-2 as a stand-alone therapy for the treatment of HIV. Maraviroc, a recently approved anti-HIV agent, is a small molecule antagonist of human chemokine receptor-5. The recent observation that maraviroc-treated patients achieved higher CD4 and CD8 T-cell counts compared with comparator regimens (without a chemokine receptor-5 antagonist) for equivalent viral load reductions has fueled interest in using these host-directed therapies to enhance immune restoration. This review summarizes the most recent clinical data for rIL-2 and reviews other immunotherapies in earlier development including cytokines rIL-7, rIL-15, rIL-21, new therapeutic vaccination approaches including infusion of overlapping HIV peptides and dendritic cell immunotherapy and novel agents including luteinizing hormone-releasing hormone analogues and vitamin D3-binding protein macrophage activating factor.

A Phase I study to explore the activity and safety of SCH532706, a small molecule chemokine receptor-5 antagonist in HIV type-1-infected patients

SCH532706 is a novel small molecule chemokine receptor-5 (CCRS) antagonist with high in vitro potency (mean 90% inhibitory concentration [IC90] 0.15-7.0 nM) against diverse HIV type-1 (HIV-1) isolates. A single arm study was undertaken to examine the safety, antiviral activity and pharmacokinetics (PK) of 10 days of SCH532706 coadministered with ritonavir (RTV). The trial enrolled formerly treated (off therapy >3 months) or untreated HIV-1-infected patients. The study enrolled 12 males with CD4+ T-cell count >100 cells/microl. Median (range) CD4+ T-cell count was 327 cells/microl (117-1008), HIV-1-RNA was 4.6 log10 copies/ml (3.8-5.5) and patients had phenotypically confirmed R5-tropic HIV-1 only. Mean (95% confidence interval) changes from baseline plasma HIV-1-RNA at days 10 and 15 (4 days off SCH532706) were -1.31 log10 copies/ml (-1.6 - -1.0) and -1.62 log10 copies/ml (-2.0 - -1.3), respectively. Day 10 median (range) time to maximum plasma concentration, mean (+/-SD) effective half-life and mean (+/-SD) trough concentration were 1.4 h (1.0-4.0), 39.4 h (+/-14.5) and 178 ng/ml (+/-34), respectively. All virus isolates remained R5-tropic pre-study, on study and at study end. There were no laboratory or QTc interval changes reportable as adverse events. In total, 11 patients reported > or =1 treatment emergent adverse event, most commonly gastrointestinal upset. One serious adverse event, pericarditis (grade 2), occurred 13 days after drug administration. It was considered to be possibly related to study drug. Overall, SCH532706 with RTV was safe, generally well tolerated and active against HIV-1 over 10 days of dosing. In this setting, SCH532706 trough concentrations exceed the mean in vitro IC90 (1.1 ng/ml) by >30-fold (after correction for 80% plasma protein binding) and provide a PK rationale for the observed efficacy.

CCR5 inhibitors: Emerging promising HIV therapeutic strategy

Though potent anti-HIV therapy has spectacularly reduced the morbidity and mortality of human immunodeficiency virus (HIV)-1 infection in the advanced countries, it continues to be associated with substantial toxicity, drug-drug interactions, difficulties in adherence, and abnormal cost. As a result, better effective, safe antiretroviral drugs and treatment strategies keep on to be pursued. In this process, CCR5 (chemokine receptor 5) inhibitors are a new class of antiretroviral drug used in the treatment of HIV. They are designed to prevent HIV infection of CD4 T-cells by blocking the CCR5. When the CCR5 receptor is unavailable, 'R5-tropic' HIV (the variant of the virus that is common in earlier HIV infection) cannot engage with a CD4 T-cell to infect the cell. In August 2007, the FDA approved the first chemokine (C-C motif) CCR5 inhibitor, maraviroc, for treatment-experienced patients infected with R5-using virus. Studies from different cohort in regions, affected by clad B HIV-1, demonstrate that 81-88% of HIV-1 variants in treatment naïve patients are CCR5 tropic and that virtually all the remaining variants are dual/mixed tropic i.e., are able to utilize both CCR5 and CXCR4 coreceptors. In treatment experienced patients, 49-78% of the variants are purely CCR5 tropic, 22-48% are dual/mixed tropic, and 2-5% exclusively utilize CXCR4. A 32 bp deletion in the CCR5 gene, which results in a frame shift and truncation of the normal CCR5 protein, was identified in a few persons who had remained uninfected after exposure to CCR5 tropic HIV-1 virus. This allele is common in white of European origin, with prevalence near to 10%, but is absent among East Asian, American Indian, Tamil Indian, and African ethnic groups. HIV-infected individuals, who are heterozygous for CCR5 delta 32, have slower rates of disease progression. The currently available data supports the continuation of the development of CCR5 antagonists in different settings related to HIV-1 infection. If safety issues do not emerge, these compounds could be positioned for use from very early stage of HIV infection to salvage strategies that would be an emerging therapeutic novel strategy for HIV/AIDS patients.

Investigating the Mechanistic Basis for Hepatic Toxicity Induced by an Experimental Chemokine Receptor 5 (CCR5) Antagonist Using a Compendium of Gene Expression Profiles

A compendium of hepatic gene expression signatures was used to identify a mechanistic basis for the hepatic toxicity of an experimental CCR5 antagonist (MrkA). Development of MrkA, a potential HIV therapeutic, was discontinued due to hepatotoxicity in preclinical studies. Rats were treated with MrkA at 3 dose levels (50, 250, and 500 mg/kg) for 1, 3, or 7 days. Hepatic toxicity (vacuolation, consistent with steatosis, and elevated serum transaminase levels) was observed at 250 and 500 mg/kg, but not at 50 mg/kg. Hepatic gene expression profiles were compared to a compendium of hepatic expression profiles. MrkA was similar to 3 beta-oxidation inhibitors (valproate, cyclopropane carboxylate, pivalate), 8 PPARalpha agonists (fenofibrate, bezafibrate and 6 fibrate analogues), and 3 other diverse compounds (diethylnitrosamine, microcystin LR & actinomycin D). These data indicate MrkA to be a mitochondrial inhibitor, and activation of PPARalpha-regulated transcription was thought to be due to an accumulation of endogenous ligands. While mitochondrial inhibition was likely responsible for steatosis, canonical pathway analysis revealed that progression to liver injury may be mediated by activation of the innate immune system primarily through NF-kB pathways. These results demonstrate the utility of a gene expression response compendium in developing transcriptional biomarkers and identifying the mechanistic basis for toxicity.

Chemokine receptor 5 antagonist d-Ala-peptide T-amide reduces microglia and astrocyte activation within the hippocampus in a neuroinflammatory rat model of Alzheimer's disease

Chronic neuroinflammation plays a prominent role in the progression of Alzheimer's disease. Reactive microglia and astrocytes are observed within the hippocampus during the early stages of the disease. Epidemiological findings suggest that anti-inflammatory therapies may slow the onset of Alzheimer's disease. Chemokine receptor 5 (CCR5) up-regulation may influence the recruitment and accumulation of glia near senile plaques; activated microglia express CCR5 and reactive astrocytes express chemokines. We have previously shown that neuroinflammation induced by chronic infusion of lipopolysaccharide into the 4th ventricle reproduces many of the behavioral, neurochemical, electrophysiological and neuropathological changes associated with Alzheimer's disease. The current study investigated the ability of d-Ala-peptide T-amide (DAPTA), a chemokine receptor 5 chemokine receptor antagonist of monocyte chemotaxis, to influence the consequences of chronic infusion of lipopolysaccharide. DAPTA (0.01mg/kg, s.c., for 14 days) dramatically reduced the number of activated microglia and astrocytes, as compared with lipopolysaccharide-infused rats treated with vehicle. DAPTA treatment also reduced the number of immunoreactive cells expressing nuclear factor κ binding protein, a prominent component of the proinflammatory cytokine signaling pathway. The present study suggests that DAPTA and other CCR5 antagonists may attenuate critical aspects of the neuroinflammation associated with Alzheimer's disease.