Interaction between RANTES promoter variant and CCR5Delta32 favors recovery from hepatitis B

Beyond HIV infection: Neglected and varied impacts of CCR5 and CCR5Δ32 on viral diseases

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CCR5 regulates multiple cell types (e.g., T regulatory and Natural Killer cells) and immune responses.

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The effects of CCR5, CCR5Δ32 (variant associated with reduced CCR5 expression) and CCR5 antagonists vary between infections.

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CCR5 affects the pathogenesis of flaviviruses, especially in the brain.

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The genetic variant CCR5Δ32 increases the risk of symptomatic West Nile virus infection.

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The triad “CCR5, extracellular vesicles and infections” is an emerging topic.

The interactions between chemokine receptors and their ligands may affect susceptibility to infectious diseases as well as their clinical manifestations. These interactions mediate both the traffic of inflammatory cells and virus-associated immune responses. In the context of viral infections, the human C-C chemokine receptor type 5 (CCR5) receives great attention from the scientific community due to its role as an HIV-1 co-receptor. The genetic variant CCR5Δ32 (32 base-pair deletion in CCR5 gene) impairs CCR5 expression on the cell surface and is associated with protection against HIV infection in homozygous individuals. Also, the genetic variant CCR5Δ32 modifies the CCR5-mediated inflammatory responses in various conditions, such as inflammatory and infectious diseases. CCR5 antagonists mimic, at least in part, the natural effects of the CCR5Δ32 in humans, which explains the growing interest in the potential benefits of using CCR5 modulators for the treatment of different diseases. Nevertheless, beyond HIV infection, understanding the effects of the CCR5Δ32 variant in multiple viral infections is essential to shed light on the potential effects of the CCR5 modulators from a broader perspective. In this context, this review discusses the involvement of CCR5 and the effects of the CCR5Δ32 in human infections caused by the following pathogens: West Nile virus, Influenza virus, Human papillomavirus, Hepatitis B virus, Hepatitis C virus, Poliovirus, Dengue virus, Human cytomegalovirus, Crimean-Congo hemorrhagic fever virus, Enterovirus, Japanese encephalitis virus, and Hantavirus. Subsequently, this review addresses the impacts of CCR5 gene editing and CCR5 modulation on health and viral diseases. Also, this article connects recent findings regarding extracellular vesicles (e.g., exosomes), viruses, and CCR5. Neglected and emerging topics in “CCR5 research” are briefly described, with focus on Rocio virus, Zika virus, Epstein-Barr virus, and Rhinovirus. Finally, the potential influence of CCR5 on the immune responses to coronaviruses is discussed.

Network pharmacology-based study on the mechanism of Yiganling capsule in hepatitis B treatment

Background

Yiganling (YGL) capsule is a traditional Chinese medicine preparation consisting of eight herbs that has been clinically proven to have a favorable treatment effect on Hepatitis B (HB). However, due to its multiple targets and multi-pharmacological effects, the mechanisms of YGL capsule in the treatment of HB are unknown.

Methods

First, the chemical constituents of YGL capsules were obtained from the Chinese medicine database, and YGL capsules were constructed. Second, active compounds were screened by the ADME model. The target fishing model was used to screen the corresponding targets of active compounds and to construct a compounds and compound targets network. Using human disease databases and literature mining, we systematically identified genes associated with HB, constructed disease-specific protein-protein interaction networks, and performed clustering and enrichment analyses of these networks. These networks were then merged to obtain a compound-disease target network, and cluster and enrichment analyses were performed on the compound-disease target network to acquire a compounds-disease targets-mechanism network and a clustering network.

Results

We successfully built eight pharmacological network diagrams, including four primary networks and other network maps. The four dominating network maps included a HB disease-associated protein-protein interaction network, a YGL capsule compounds-target network, a YGL capsule ingredient target-HB disease target network, and a YGL-HB disease mechanism network. Other networks included a pathway of HB disease targets, the HB disease protein-protein interaction cluster analysis network, and the YGL-HB target clustering network.

Conclusion

This study successfully forecasted, illuminated, and confirmed the synergistic effects of HB disease molecules and discovered the potential of HB relevant targets, clusters, and target-related biological processes and signaling pathways. Our research not only provides theoretical support for the molecular and pharmacological mechanisms of YGL capsule in HB treatment, but also provides new research methods for the study of the other traditional Chinese medicinal compounds.

Role of the genetic variant CCR5Δ32 in HBV infection and HBV/HIV co-infection

CCR5 is a chemokine receptor that mediates the action of inflammatory cells, besides acting as an HIV co-receptor. CCR5Δ32 states for a genetic variant containing a 32 base pair deletion in the coding region of the CCR5 gene. In homozygosis, CCR5Δ32 results in the lack of CCR5 expression on the cell surface, which was associated with protection against HIV infection. Heterozygous individuals for CCR5Δ32 have a reduced CCR5 expression. Recent evidence demonstrates that CCR5 and CCR5Δ32 are involved in the pathogenesis of other viral infections besides HIV infection. Nevertheless, the role of CCR5 and CCR5Δ32 in HBV infection is not clear and conflicting results have been reported. Thus, the objective of this study was to investigate the role of CCR5Δ32 in HBV mono-infection and HBV/HIV co-infection in a population from southern Brazil. A total of 1113 individuals were evaluated, divided in controls (n = 334), HBV+ (n = 335), HBV+/HIV+ (n = 144), and including an HIV+ group to complement the analyses (n = 300, obtained from a previous study of our research team). The CCR5Δ32 allele frequencies found were 7.5 %, 9.0 %, and 3.1 %, respectively for controls, HBV+, and HBV+/HIV+ patients. The individuals were classified in CCR5Δ32 allele carriers and CCR5Δ32 allele non-carriers and the groups were compared using binary logistic regression adjusted for covariates. No significant effect of the CCR5Δ32 variant was observed on the susceptibility or protection against HBV mono-infection in individuals from southern Brazil. A potential protective effect of CCR5Δ32 on HBV/HIV co-infection was observed. However, it can be due to the effect of CCR5Δ32 in the protection against HIV infection or external factors not covered in the study. Finally, this study contributes to the understanding of the role of CCR5 in HBV infection, suggesting no effect of CCR5Δ32 on susceptibility to HBV mono-infection.

CCR5 Polymorphism as a Protective Factor for Hepatocellular Carcinoma in Hepatitis B Virus-Infected Iranian Patients

The CC chemokine receptor 5 (CCR5) delta 32 allele results in a nonfunctional form of the chemokine receptor and has been implicated in a variety of immune-mediated diseases. CCR5Δ32 may also predispose one to chronic liver disease or be linked with resistance to HBV infection. This study was undertaken to investigate any association between CCR5 polymorphism with resistance to hepatitis B or susceptibility to HBV infection. A total of 812 Iranian individuals were enrolled into two groups: HBV infected cases (n=357), who were HBsAg-positive, and healthy controls (n=455). We assessed polymorphisms in the CCR5 gene using specific CCR5 oligonucleotide primers surrounding the breakpoint deletion. Genotype distributions of the HBV infected cases and healthy controls were determined and compared. The CCR5/CCR5 (WW) and CCR5/CCR5Δ32 (W/D) genotypes were found in (98%) and (2%) of HBV infected cases, respectively. The CCR5 Δ32/Δ32genotype was not found in HBV infected cases. Genotype distributions of CCR5 in healthy controls were W/W genotype in (87.3%), W/D genotype in (11.2%) and D/D genotype in (1.5%). Heterozygosity for CCR5/CCR5Δ32 (W/D) in healthy controls was greater than in HBV infected cases (11.2% vs 2%, p < 0.001). W/D and D/D genotypes were more prominent in healthy controls than in HBV infected cases. This study provides evidence that the CCR5Δ32 polymorphism may have a protective effect in resistance to HBV infection at least in the Iranian population.

Host genetic variants influencing the clinical course of hepatitis B virus infection

The clinical course of hepatitis B virus (HBV) infection greatly differs in individuals. Various viral, host, and environmental factors influence the natural history of HBV infection. Recent genome-wide association studies identified several host genetic factors influencing the clinical course of HBV infection. Genetic variations in HLA class II loci were significantly associated with susceptibility to persistent HBV infection. Other polymorphisms in or near the genes EHMT2, TCF19, and HLA-C, located near HLA class II loci, and UBE2L3 were also associated with persistent HBV infection. Meanwhile, polymorphisms in KIF1B, GRIK1, and STAT4 were associated with HBV-related hepatocellular carcinoma (HCC). Interestingly, HLA class II genetic variations were strongly associated with not only persistent HBV infection, but also disease progression and HBV-related HCC in chronic hepatitis B. Understanding the various genetic factors associated with the clinical course of HBV infection is essential for personalized treatment and surveillance of disease progression and HCC.

CCR5 on the NK Cells and its Ligand (RANTES) Expressions are Disrupted in South-Eastern Iranian Patients With Chronic Hepatitis B Infection

Background:

CCR5 is a receptor for CCL3 (MIP-1 α), CCL4 (MIP-1 α) and CCL5 (regulated on activation normal T cell expressed and secreted (RANTES)) and play important roles in recruitment of NK cells to the HBV infected liver.

Objectives:

The main purpose of this study was to investigate the expression levels of CCR5 on the NK cells and also serum levels of RANTES in chronic HBV infected (CHI) patients.

Materials and Methods:

In this descriptive study 63 CHI patients and 96 healthy controls were evaluated regarding CCR5 expression on the NK cells and serum levels of RANTES using flow cytometry and ELISA techniques, respectively. Real-Time PCR technique also was used for HBV-DNA quantification.

Results:

The results revealed that CCR5 expressing NK cells and serum levels of RANTES were decreased significantly in the CHI patients in compare to healthy control.

Conclusions:

Based on the results it can be concluded that NK cells of Iranian CHI patients are unable to express adequate levels of CCR5 and expression levels of RANTES by immune cells also are defected in CHI patients, hence, the migration of NK cells to the infected hepatocytes and HBV eradication from the cells is interrupted.

CCR5 plays important roles in hepatitis B infection

In humans, hepatitis B virus (HBV) is the most prevalent and the main infectious agent that leads to liver disease. Previous investigations identified that long-term HBV-infected patients are unable to eradicate HBV completely from hepatocytes. The main mechanisms responsible for long-term forms of the infections are yet to be clarified. However, researchers believe that the differences in genetic and immunological parameters in the patients in comparison to subjects who successfully clear HBV infections may be the causes for long-term infection. Previous studies demonstrated that chemokines play important roles in the regulation of immune cell migration and activation, which is crucial for a comprehensive immune response against HBV. RANTES, MIP-1α, and MIP-1β are important CC chemokines which act through CC chemokines receptor 5 (CCR5). This receptor is expressed on several effector immune cells including NK cells, T lymphocytes, and macrophages, and plays a crucial role in the regulation of activation and migration of the immune cells during immune responses against viruses, including HBV. Therefore, alterations in its expression or functions could be associated with attenuated immune responses against HBV. In addition, previous studies identified that a 32 base pair deletion (Δ32) in exon 1, as well as three polymorphisms in the promoter region of the CCR5 gene results in downregulation of the molecule. Previous studies revealed that CCR5 expression was altered in hepatitis B but the role of the CCR5 Δ32 mutation and CCR5 promoter polymorphisms in this disease is controversial. This review addresses the recent information regarding the status of CCR5 expression on immune cells and the association of CCR5 promoter polymorphisms with HBV-infected patients.

Targeting CCL5 in inflammation

INTRODUCTION

Chemokines play important roles in inflammation and in immune responses. This article will discuss the current literature on the C-C chemokine ligand 5 (CCL5), and whether it is a therapeutic target in the context of various allergic, autoimmune or infectious diseases.

AREAS COVERED

Small-molecule inhibitors, chemokine and chemokine receptor-deficient mice, antibodies and modified chemokines are the current tools available for CCL5 research, and there are several ongoing clinical trials targeting the CCL5 receptors, CCR1, CCR3 and CCR5. There are fewer studies specifically targeting the chemokine itself and clinical studies with anti-CCL5 antibodies are still to be carried out.

EXPERT OPINION

Although clinical trials are strongly biased toward HIV treatment and prevention with blockers of CCR5, the therapeutic potential for CCL5 and its receptors in other diseases is relevant. Overall, it is not likely that specific targeting of CCL5 will result in new adjunct strategies for the treatment of infectious diseases with a major inflammatory component. However, targeting CCL5 could result in novel therapies for chronic inflammatory diseases, where it may decrease inflammatory responses and fibrosis, and certain solid tumors, where it may have a role in angiogenesis.

A novel variant marking HLA-DP expression levels predicts recovery from hepatitis B virus infection

Variants near the HLA-DP gene show the strongest genome-wide association with chronic hepatitis B virus (HBV) infection and HBV recovery/persistence in Asians. To test the effect of the HLA-DP region on outcomes to HBV infection, we sequenced the polymorphic HLA-DPB1 and DPA1 coding exons and the corresponding 3' untranslated regions (3'UTRs) in 662 individuals of European-American and African-American ancestry. The genome-wide association study (GWAS) variant (rs9277535; 550A/G) in the 3'UTR of the HLA-DPB1 gene that associated most significantly with chronic hepatitis B and outcomes to HBV infection in Asians had a marginal effect on HBV recovery in our European- and African-American samples (odds ratio [OR] = 0.39, P = 0.01, combined ethnic groups). However, we identified a novel variant in the HLA-DPB1 3'UTR region, 496A/G (rs9277534), which associated very significantly with HBV recovery in both European and African-American populations (OR = 0.37, P = 0.0001, combined ethnic groups). The 496A/G variant distinguishes the most protective HLA-DPB1 allele (DPB1*04:01) from the most susceptible (DPB1*01:01), whereas 550A/G does not. 496A/G has a stronger effect than any individual HLA-DPB1 or DPA1 allele and any other HLA alleles that showed an association with HBV recovery in our European-American cohort. The 496GG genotype, which confers recessive susceptibility to HBV persistence, also associates in a recessive manner with significantly higher levels of HLA-DP surface protein and transcript level expression in healthy donors, suggesting that differences in expression of HLA-DP may increase the risk of persistent HBV infection.

RANTES gene polymorphisms (-403G>A and -28C>G) associated with hepatitis B virus infection in a Saudi population

Besides the host immune response, genetic and environmental factors play crucial roles in the manifestation of hepatitis B virus (HBV) infection. "Regulated on activation normal T-cell expressed and secreted" factor (RANTES) plays a vital role in CD4(+), CD8(+) T-lymphocyte and dendritic cell activation and proliferation in inflammation. Single nucleotide polymorphisms (SNPs) in the RANTES gene are associated with several viral and non-viral diseases. Association studies have invariably indicated a lack of association between RANTES gene SNPs and HBV infection in ethnic populations, even though RANTES gene SNPs exhibit distinct ethnic distributions. Despite the high prevalence of HBV infections in Saudi Arabia, no studies have been made concerning a possible relationship between RANTES gene polymorphisms and susceptibility to and progression of HBV infection. We examined -403G>A and -28C>G RANTES gene variants in 473 healthy controls and 484 HBV patients in ethnic Saudi populations. Significant differences were found in the genotype and allele distributions of the SNPs between the controls and the HBV patients. Both SNPs were significantly linked to viral clearance in these subjects. Our data demonstrate for the first time in a Saudi population, a relationship between the RANTES gene polymorphisms and the clinical course of HBV infection and underscore the importance of evaluating the genetic background of the affected individual to determine how it may affect disease progression.

Polymorphisms of CCL3L1/CCR5 genes and recurrence of hepatitis B in liver transplant recipients

BACKGROUND

The genetic diversity of chemokines and chemokine receptors has been associated with the outcome of hepatitis B virus infection. The aim of this study was to evaluate whether the copy number variation in the CCL3L1 gene and the polymorphisms of CCR5Δ32 and CCR5-2459A→G (rs1799987) are associated with recurrent hepatitis B in liver transplantation for hepatitis B virus infection-related end-stage liver disease.

METHODS

A total of 185 transplant recipients were enrolled in this study. The genomic DNA was extracted from whole blood, the copy number of the CCL3L1 gene was determined by a quantitative real-time PCR based assay, CCR5Δ32 was detected by a sizing PCR method, and a single-nucleotide polymorphism in CCR5-2459 was detected by restriction fragment length polymorphism PCR.

RESULTS

No CCR5Δ32 mutation was detected in any of the individuals from China. Neither copy number variation nor polymorphism in CCR5-2459 was associated with post-transplant re-infection with hepatitis B virus. However, patients with fewer copies (<4) of the CCL3L1 gene compared with the population median in combination with the CCR5G allele had a significantly higher risk for recurrent hepatitis B (odds ratio=1.93, 95% CI: 1.00-3.69; P=0.047).

CONCLUSION

Patients possessing the compound decreased functional genotype of both CCL3L1 and CCR5 genes might be more likely to have recurrence of hepatitis B after transplantation.

Drug safety evaluation of maraviroc for the treatment of HIV infection

INTRODUCTION

Maraviroc is the only C-chemokine receptor 5 (CCR5) antagonist approved for the treatment of infection with HIV. This article reviews the safety and efficacy of maraviroc in the treatment of HIV infection.

AREAS COVERED

The PubMed database was searched using the keywords 'maraviroc' and 'HIV'. In addition, conference proceedings from CROI, IAS and EACS meetings were searched for maraviroc clinical trials. The PubMed search revealed one Phase IIb - III clinical trial in treatment-naive HIV(+) patients (MERIT) and three Phase IIb - III randomized clinical trials (RCTs) in treatment-experienced patients (MOTIVATE 1 and 2, A4001029). All RCTs showed an excellent safety profile for maraviroc in the treatment of HIV-1 infection. However, long-term (> 3 years) safety data generated on maraviroc therapy are still scarce. Based on the findings from RCTs so far, no relevant toxicities and co-morbidities such as coronary heart disease or hepatotoxicity have been described. The overall CD4(+) cell count increase resulting from a maraviroc-containing regimen appears to be higher than those seen with other antiretroviral regimens. However, the significance remains controversial. To date, maraviroc has shown a potent and durable virological efficacy profile for the treatment of HIV-1 infection. The only use of maraviroc depends on pretreatment testing for CCR5 tropism.

EXPERT OPINION

Maraviroc is a generally safe and well-tolerated medication for the treatment of HIV-1 infection with a unique mechanism of action. Long-term (i.e., > 5 years) risks are not known and have to be carefully monitored.

Clinical use of CCR5 inhibitors in HIV and beyond

Since the discovery of CCR5 as a coreceptor for HIV entry, there has been interest in blockade of the receptor for treatment and prevention of HIV infection. Although several CCR5 antagonists have been evaluated in clinical trials, only maraviroc has been approved for clinical use in the treatment of HIV-infected patients. The efficacy, safety and resistance profile of CCR5 antagonists with a focus on maraviroc are reviewed here along with their usage in special and emerging clinical situations. Despite being approved for use since 2007, the optimal use of maraviroc has yet to be well-defined in HIV and potentially in other diseases. Maraviroc and other CCR5 antagonists have the potential for use in a variety of other clinical situations such as the prevention of HIV transmission, intensification of HIV treatment and prevention of rejection in organ transplantation. The use of CCR5 antagonists may be potentiated by other agents such as rapamycin which downregulate CCR5 receptors thus decreasing CCR5 density. There may even be a role for their use in combination with other entry inhibitors. However, clinical use of CCR5 antagonists may have negative consequences in diseases such as West Nile and Tick-borne encephalitis virus infections. In summary, CCR5 antagonists have great therapeutic potential in the treatment and prevention of HIV as well as future use in novel situations such as organ transplantation. Their optimal use either alone or in combination with other agents will be defined by further investigation.

Chemokine (CCR) and fractalkine (CX3CR) receptors and end stage renal disease

OBJECTIVE AND DESIGN

Genetic polymorphisms of chemokines and their receptors were reported to be independent risk factors for inflammation associated disease. We explored the role of CCR5-Δ32, CCR5-G59029A, CX3CR1 V249I and T280M gene polymorphisms as susceptibility for end stage renal disease (ESRD).

SUBJECTS AND METHODS

We genotyped 258 ESRD and 569 healthy controls by sequence-specific primers and RFLP and examined their association.

RESULTS

There was significant difference in genotype frequencies of CCR5-G59029A (p = 0.005), and CX3CR1 V249I (p < 0.0001) between ESRD and controls. No homozygous individuals were observed for CCR5-Δ32. The haplotype analysis of all four studied genes reveled that haplotype +/A/T/I was more significant in patients and associated with higher risk (OR = 2.95) of ESRD. Further, the haplotype of CX3CR1 (T280M, V249I) gene showed 3.6-fold higher in an individual carrying T/I haplotype. No risk was seen for CCR5 haplotypes.

CONCLUSIONS

These results highlight the role of CCR5 and CX3CR1 in ESRD.

CCR5 antagonists: host-targeted antiviral agents for the treatment of HIV infection, 4 years on

The chemokine coreceptor 5 (CCR5) antagonists are antiretroviral agents with an extracellular, host-targeted mechanism of action against HIV. Maraviroc, the first-in-class CCR5 antagonist, received regulatory approval in 2007, becoming the first oral antiretroviral from a new class in more than 10 years. Other compounds in this class are in various stages of clinical development. In 2005, we reviewed the limited clinical data then available on CCR5 antagonists. In this follow-up review, we revisit the field and assess the clinical and virological data that have emerged in the 4 years since, with particular reference to maraviroc for which the most comprehensive data currently exist.

Genetic interactions between the donor and the recipient for susceptibility to acute rejection in kidney transplantation: polymorphisms of CCR5

BACKGROUND

Acute rejection (AR) contributes to the development of chronic allograft nephropathy that is the major cause of graft failure. We analyzed the 59029G>A polymorphism and an internal 32 bp deletion (CCR5 32) of CCR chemokine receptor 5 (CCR5) Delta and tried to prove the hypothesis that genetic interactions between the donor and the recipient influence the development of AR.

METHODS

We detected genetic polymorphisms by the TaqMan(R) method and by sizing PCR amplicons (n = 486). The primary outcomes were early acute rejection (EAR) and repeated early acute rejection (RR). We defined EAR as the occurrence of a biopsy-proven AR within 3 months after transplantation.

RESULTS

The development of EAR was dependent on the number of A alleles in recipients and showed a dose-response relationship (P = 0.002). When we combined the number of A alleles in both donor and recipient, episodes of EAR and RR were more prevalent as the allelic number increased (A allelic number 0 & 1, 2 versus 3 & 4, P = 0.048; 0 & 1 versus 3 & 4, P = 0.006). Statistical significance was preserved after multivariate analysis of sex, HLA mismatch and type of donor with the recipient's age as the continuous term. Also, graft survival was different according to the presence of the A allele, i.e. recipients carrying A allele (+) grafts showed poor graft survival (P = 0.008 by a log-rank test). Again, the number of A alleles affected graft survival as the recipients who carried more A alleles had poor graft survival (A allele number 0 & 1 versus 2 versus 3 & 4, P = 0.011; 0 & 1 versus 3 & 4, P = 0.08; 0 & 1 versus 2, P = 0.002; by a log-rank test). All of the participants were wild-type homozygotes for CCR5Delta32.

CONCLUSIONS

The A allele of CCR5 59029G>A was a risk factor for EAR and RR. As the number of A alleles increased, episodes of EAR were more frequently observed.