Haplotype analysis of the SDF-1 (CXCL12) gene in a longitudinal HIV-1/AIDS cohort study

Low prevalence of HIV in the northern Cameroon: contribution of some AIDS restriction genes and potential implications for gene therapy

Background

HIV infection and its progression to AIDS depend on several factors including host genetic factors. The immunological mechanisms of host resistance to HIV infection greatly influence the prevalence of HIV in a given region. Worldwide, Cameroon not exempted, the frequency of AIDS-associated genes varies and may influence this prevalence. The North and Far North Regions of Cameroon have had the lowest HIV prevalence in the country for many years despite risky behaviors associated with their customs and habits. In this work, we seek to explore the contribution of host genes to the HIV low prevalence in these regions.

Methodology

Five genes variants previously described as HIV AIDS related were studied. These genes are: CCR5Δ32, CCR5promoter59029G, CCR2-64I, SDF1-3'A and Trim5α(R136Q). A total of 384 consented participants were included in this study. The HIV serological status was confirmed using national algorithm. Genomic DNA was extracted from the buffy coats and used for genotyping. The results obtained were compiled in Excel 2016, Epi Info 7.1 and snpStats software and Chi two tests allowed us to compare the frequencies of the AIDS related alleles in the North with those in other Regions of Cameroon and to measure the impact of these ARGs on protection against HIV.

Results

The frequency of protective alleles CCR5Δ32, CCR5promoter59029G, CCR2-64I, SDF1-3'A and Trim5α(R136Q) was the allelic frequencies should be expressed as percentages i.e. 0.52%; 37.56%; 36.46%; 25.19% and 69.33%. These allelic frequencies exhibited a significant difference when compared to those obtained in other regions of Cameroon (p < 0.01). Protective alleles were predominant in the Northern region compared to others and were associated with resistance to HIV [(p < 0.0001); OR = 2.02 CI, 95%].

Conclusion

The higher frequency of HIV-protective alleles in the northern regions may be a contributing factor to the lower prevalence of HIV. Nevertheless, this should be reinforced by other preventive and surveillance methods to guarantee the sustained low prevalence. HIV can develop resistance through the process of mutation, but the host targets themselves are genetically stable. The study of these host genetic restriction factors is of great value in the design of a practical cure for HIV infection or an effective vaccine.

Genetic clues to COVID-19 severity: exploring the stromal cell-derived factor-1/CXCL12 rs2839693 polymorphism in adult Egyptians

BACKGROUND

A novel corona virus called SARS-CoV-2 was identified at the end of December 2019, and the illness induced by it was designated as coronavirus disease 2019 (COVID-19). Severity of the disease could vary significantly since most of the infected individuals experience mild to moderate respiratory symptoms and recover without specialized care. Genetic polymorphisms have implications in influencing the varying degrees of COVID-19 severity. This study aims to assess the potential association between the CXCL12 rs2839693 polymorphism and the severity of COVID-19 in Assiut University Quarantine Hospital during the period from May 2022 to August 2022.

METHODS

The present study is a cross-sectional study and is applied to 300 COVID-19 patients confirmed by RT-PCR admitted to Assiut University Quarantine Hospital from May 2022 to August 2022. Based on the clinical symptoms, the recruited participants had been divided into two groups. Group I involved mild or moderate cases; Group II involved severe or critical conditions. The rs2839693 polymorphism was detected by real time PCR using TaqMan assay probe.

RESULTS

The frequency of the T allele and the TT genotype was significantly higher in the severe or critical group compared with the mild or moderate group (p value < 0.001). C-reactive protein (CRP) and D-dimers are significantly elevated in the combined variants (CT + TT) and the TT compared with the CC (P value 0.006 and 0.017 respectively) and the CC,CT genotypes (p value 0.019 and 0.002 respectively). The combined variants (CT + TT) of CXCL12 were found to be independent predictors to severe or critical COVID-19 risk with P value =  < 0.001, OR = 3.034& 95% CI = 1.805-5.098.

CONCLUSION

Our findings revealed that CXCL12 rs2839693 had a role in the development and seriousness of COVID-19. Patients with the TT genotype or the T allele at increased risk developed severe or critical rather than mild or moderate disease.

Neurocognitive Impairment and Associated Genetic Aspects in HIV Infection

HIV enters the central nervous system (CNS) early after infection. HIV-associated neurocognitive disorders (HAND) remain a serious complication of HIV infection despite available antiretroviral therapy (ART). Neurocognitive deficits observed in HAND are heterogeneous, suggesting a variability in individuals' susceptibility or resiliency to the detrimental CNS effects of HIV infection. This chapter reviews primary host genomic changes (immune-related genes, genes implicated in cognitive changes in primary neurodegenerative diseases), epigenetic mechanisms, and genetic interactions with ART implicated in HIV progression or HAND/neurocognitive complications of HIV. Limitations of the current findings include diversity of the HAND phenotype and limited replication of findings across cohorts. Strategies to improve the precision of future (epi)genetic studies of neurocognitive consequences of HIV infection are offered.

Association of gene polymorphism of SDF1(CXCR12) with susceptibility to HIV-1 infection and AIDS disease progression: A meta-analysis

OBJECTIVES

Genetic polymorphism of viral receptors is relevant to risks of HIV-1 infection, while it is still under debated whether the polymorphism of SDF1, a unique ligand for HIV-1 coreceptor CXCR4, is associated with HIV susceptibility and AIDS disease progression. Therefore, we provided an updated quantitative assessment by meta-analysis from 16 case-control and 7 cohort studies.

METHODS

Articles reporting the relationship between SDF1 polymorphism and HIV susceptibility or AIDS progression were retrieved from PubMed, Embase and Ovid electronic databases up to Apr 2017. Data were pooled by odds ratios (ORs) for HIV-1 infection with 95% confidence intervals (CIs) and summary relative hazards (RHs) for AIDS progression with 95% CIs using 1987 Center for Disease Control (CDC) case definition of AIDS (CDC87) and 1993 Center for Disease Control (CDC) case definition of AIDS (CDC93) and death as endpoints.

RESULTS

As a result, 16 studies regarding susceptibility to HIV-1 infection with 2803 HIV-infected patients and 3697 healthy individuals and 7 studies regarding disease progression with 4239 subjects were included in the meta-analysis. For risks of infection, no evidences indicated SDF1 polymorphism was associated with the risk of HIV-1 infection in all genetic models (recessive model: OR = 0.94, 95% Cl: 0.75-1.17; homozygous model: OR = 0.89, 95% Cl: 0.70-1.15; heterozygous model: OR = 1.06, 95% Cl: 0.83-1.35; allele model: OR = 0.95, 95% Cl: 0.79-1.13), Furthermore, we failed to find an delayed AIDS progression except in some specific cohorts including MACS cohorts (RH = 0.38, 95% Cl: 0.17-0.59 for time to AIDS; RH = 0.27, 95% Cl: 0.07-0.46 for time to death at the study entry).

CONCLUSIONS

Overall, no significant association was found between SDF1 polymorphism and HIV susceptibility. A protective effect of SDF1 on AIDS progression and death was seen especially in two studies based on the same cohorts. In conclusion, SDF1 polymorphism exerts a moderate protective effect against AIDS disease deterioration in some specific populations.

Association of rs1801157 single nucleotide polymorphism of CXCL12 gene in breast cancer in Pakistan and in-silico expression analysis of CXCL12-CXCR4 associated biological regulatory network

Background

C-X-C chemokine ligand 12 (CXCL12) has important implications in breast cancer (BC) pathogenesis. It is selectively expressed on B and T lymphocytes and is involved in hematopoiesis, thymocyte trafficking, stem cell motility, neovascularization, and tumorigenesis. The single nucleotide polymorphism (SNP) rs1801157 of CXCL12 gene has been found to be associated with higher risk of BC.

Methods

Our study focuses on the genotypic and allelic distribution of SNP (rs1801157; G/A) in Pakistani population as well as its association with the clinico-pathological features. The association between rs1801157 genotypes (G/A) and BC risks was assessed by a multivariate logistic regression (MLR) analysis. Genotyping was performed in both healthy individuals and patients of BC using PCR-restriction fragment length polymorphism (PCR-RFLP) method. Furthermore, in-silico approaches were adapted to investigate the association of CXCL12 and its receptor CXCR4 with genes/proteins involved in BC signalling.

Results

Significant differences in allelic and genotypic distribution between BC patients and healthy individuals of genotype (G/G) and (A/G) (p < 0.05) were observed. The frequency of the allele G in the BC group (77%) was significantly higher as compared to control group (61%) (p = 0.01). The association of genotype GG with clinico-pathological features including age, stages of cancer and organ (lung, liver, bones and brain) metastasis (p > 0.05) was assessed. In a MLR analysis, a number of variables including age, weight of an individual, affected lymph nodes, hormonal status (estrogen and progesterone receptor), alcohol consumption and family history associated with the GG genotype (GG:AA, odds ratio (OR) = 1.30, 95% CI [1.06–1.60]) were found to be independent risk factors for BC. Our in-vitro results suggest that genotype GG is possibly increasing the risk of BC in Pakistani cohorts. in-silico analysis finds that CXCL12–CXCR4 is associated with an increased expression of PDZK1, PI3k and Akt which lead the breast tumor towards metastasis.

Conclusion

Multiple targets such as CXCL12, CXCR4, PDZK1, PI3k and Akt can be inhibited in combined strategies to treat BC metastasis.

Short Communication: CXCL12 rs1029153 Polymorphism Is Associated with the Sustained Virological Response in HIV/Hepatitis C Virus-Coinfected Patients on Hepatitis C Virus Therapy

The immune response against HIV and hepatitis C virus (HCV) infection partly depends on chemokine-mediated recruitment of specific T cells. CXCL12 polymorphisms have been associated with AIDS progression and survival, but there are no data related to HCV infection. The aim of this study was to determine whether CXCL12 polymorphisms are related so as to achieve sustained virological response (SVR) after HCV therapy with pegylated-interferon-alpha/ribavirin (pegIFN-α/ribavirin) in HIV/HCV-coinfected patients. We carried out a retrospective study in 319 naive patients who started HCV treatment. The CXCL12 (rs266093, rs1029153, and rs1801157) and IL28B (rs12980275) polymorphisms were genotyped by using the GoldenGate assay. Genetic data were analyzed under an additive inheritance model. The overall rates of the SVR were 54.9% (175/319) and 41.5% (90/217) in GT1/4 patients and 83.2% (84/101) in GT2/3 patients. Patients with a favorable CXCL12 rs1029153 T allele had higher SVR rates than patients with the rs1029153 CC genotype (44% CC, 49% CT, and 61.3% TT; p = 0.025). No significant results for the rs266093 and rs1801157 polymorphisms were found. Patients harboring the favorable rs1029153 T allele had significantly increased odds of achieving SVR [adjusted odds ratio (aOR) = 1.55; 95% confidence interval (95% CI) = 1.01; 2.40; p = 0.047]. Moreover, no significant association was found when the study population was stratified by HCV genotype (data not shown), possibly due to the low number of patients in each group. In conclusion, in this study we found that the favorable CXCL12 rs1029153 T allele seems to be related so as to achieve an SVR in HIV/HCV-coinfected patients on pegIFN-α/ribavirin therapy.

Association study of common genetic variants and HIV-1 acquisition in 6,300 infected cases and 7,200 controls

Multiple genome-wide association studies (GWAS) have been performed in HIV-1 infected individuals, identifying common genetic influences on viral control and disease course. Similarly, common genetic correlates of acquisition of HIV-1 after exposure have been interrogated using GWAS, although in generally small samples. Under the auspices of the International Collaboration for the Genomics of HIV, we have combined the genome-wide single nucleotide polymorphism (SNP) data collected by 25 cohorts, studies, or institutions on HIV-1 infected individuals and compared them to carefully matched population-level data sets (a list of all collaborators appears in Note S1 in Text S1). After imputation using the 1,000 Genomes Project reference panel, we tested approximately 8 million common DNA variants (SNPs and indels) for association with HIV-1 acquisition in 6,334 infected patients and 7,247 population samples of European ancestry. Initial association testing identified the SNP rs4418214, the C allele of which is known to tag the HLA-B*57:01 and B*27:05 alleles, as genome-wide significant (p = 3.6×10⁻¹¹). However, restricting analysis to individuals with a known date of seroconversion suggested that this association was due to the frailty bias in studies of lethal diseases. Further analyses including testing recessive genetic models, testing for bulk effects of non-genome-wide significant variants, stratifying by sexual or parenteral transmission risk and testing previously reported associations showed no evidence for genetic influence on HIV-1 acquisition (with the exception of CCR5Δ32 homozygosity). Thus, these data suggest that genetic influences on HIV acquisition are either rare or have smaller effects than can be detected by this sample size.

Comparing the frequency differences between common DNA variants in disease-affected cases and in unaffected controls has been successful in uncovering the genetic component of multiple diseases. This approach is most effective when large samples of cases and controls are available. Here we combine information from multiple studies of HIV infected patients, including more than 6,300 HIV+ individuals, with data from 7,200 general population samples of European ancestry to test nearly 8 million common DNA variants for an impact on HIV acquisition. With this large sample we did not observe any single common genetic variant that significantly associated with HIV acquisition. We further tested 22 variants previously identified by smaller studies as influencing HIV acquisition. With the exception of a deletion polymorphism in the CCR5 gene (CCR5Δ32) we found no convincing evidence to support these previous associations. Taken together these data suggest that genetic influences on HIV acquisition are either rare or have smaller effects than can be detected by this sample size.

Common human genetic variants and HIV-1 susceptibility: a genome-wide survey in a homogeneous African population

OBJECTIVE

To date, CCR5 variants remain the only human genetic factors to be confirmed to impact HIV-1 acquisition. However, protective CCR5 variants are largely absent in African populations, in which sporadic resistance to HIV-1 infection is still unexplained. We investigated whether common genetic variants associate with HIV-1 susceptibility in Africans.

METHODS

We performed a genome-wide association study (GWAS) in a population of 1532 individuals from Malawi, a country with high prevalence of HIV-1 infection. Using single-nucleotide polymorphisms (SNPs) present on the genome-wide chip, we also investigated previously reported associations with HIV-1 susceptibility or acquisition. Recruitment was coordinated by the Center for HIV/AIDS Vaccine Immunology at two sexually transmitted infection clinics. HIV status was determined by HIV rapid tests and nucleic acid testing.

RESULTS

After quality control, the population consisted of 848 high-risk seronegative and 531 HIV-1 seropositive individuals. Logistic regression testing in an additive genetic model was performed for SNPs that passed quality control. No single SNP yielded a significant P value after correction for multiple testing. The study was sufficiently powered to detect markers with genotype relative risk 2.0 or more and minor allele frequencies 12% or more.

CONCLUSION

This is the first GWAS of host determinants of HIV-1 susceptibility, performed in an African population. The absence of any significant association can have many possible explanations: rarer genetic variants or common variants with weaker effect could be responsible for the resistance phenotype; alternatively, resistance to HIV-1 infection might be due to nongenetic parameters or to complex interactions between genes, immunity and environment.

CXCL12: a new player in coronary disease identified through human genetics

Genome-wide association studies (GWAS) of more than 100,000 people have revealed novel loci associated with coronary artery disease and myocardial infarction that present exciting opportunities to discover novel disease pathways. One such recently identified locus is on chromosome 10q11, near the gene for the chemokine CXCL12, which has been implicated in cardiovascular disease in both mouse and human studies. These GWAS demonstrate that CXCL12 may emerge as a potential therapeutic target for atherosclerosis and thrombosis.

Genetic variation in CXCL12 and risk of cervical carcinoma: a population-based case-control study

CXCL12 provides a chemotactic signal-directing leucocyte migration and regulates metastatic behaviour of tumour cells. We conducted a population-based case-control study to test the hypothesis that common genetic variation in CXCL12 individual single nucleotide polymorphism (SNP) alleles and haplotypes] is associated with the risk of cervical carcinoma. Cases (n = 917) were residents of western Washington State diagnosed with invasive squamous cell cervical carcinoma (SCC), invasive adenocarcinoma or adenosquamous carcinoma, or adenocarcinoma in situ of the cervix. Control participants (n = 849) were identified from the source population by random digit telephone dialling and frequency matched to cases on county and age. Nine CXCL12 tagSNPs chosen from the SeattleSNPs database were genotyped. The minor allele of intronic SNP rs266085 was inversely associated with cervical cancer under a recessive genetic effects model (OR = 0.74, 95% CI: 0.56-0.98). Among the ten common haplotypes inferred from the nine tagSNPs, one haplotype defined by minor alleles at 5'-flanking SNP rs17885289 and rs266085, and common alleles at the other seven SNPs occurred among 7.8% of cases and 10.6% of controls (dominant model OR = 0.72, 95% CI: 0.56-0.93; recessive model OR = 0.35, 95% CI: 0.12-0.97; and log-additive model OR = 0.72, 95% CI: 0.57-0.90). A stepwise procedure identified rs17885289, rs266085 and 3'-untranslated region (UTR) SNP rs266093 as the most parsimonious subset of SNPs necessary to define the haplotype inversely associated with cervical cancer risk in our study. A 3'-UTR SNP, rs1801157, previously found to be related to HIV pathogenesis, was not associated with cervical cancer risk. Further population-based studies are warranted to confirm these associations between genetic variation in CXCL12 and cervical cancer risk.

RANTES -28G delays and DC-SIGN - 139C enhances AIDS progression in HIV type 1-infected Japanese hemophiliacs

The relationships between host immune factors and HIV-1 disease progression are still in dispute. Unlike CCR5Delta32, which has been found to delay disease progression of HIV-1, there still remain several factors whose effect on the clinical course is unconfirmed. To clarify the relationships, we selected seven single-nucleotide polymorphisms (SNPs) out of the previously reported factors, namely, RANTES promoter -28G/-403A, RANTES In1.1C, SDF-1 3'A, IL-4 promoter -589T, and DC-SIGN promoter -139C/-336C, and examined these in Japanese HIV-1-infected hemophiliacs (n = 102). The genotypes were examined by the direct sequencing method, and the distributions of genotype and allelic frequencies were compared between two groups, slow progressors (n = 54) who did not develop AIDS more than 10 years after intravenous infection and others (progressors) (n = 48). The allelic frequency of RANTES -28G was significantly higher in slow progressors (0.185) than in the progressor group (0.074) [p = 0.023, OR = 0.35, 95% CI (0.142, 0.880)]. DC-SIGN promoter -139C, and appeared in progressors with significantly higher allelic frequency (0.333) than slow progressors [0.204, p = 0.040, OR = 1.95, 95% CI (1.039, 3.677)]. With RANTES -403A, RANTES In1.1C, SDF-1 3' A, IL-4 -589T, and DC-SIGN -336C, no significant difference was observed in allelic frequencies between the two groups. These results suggest that RANTES -28G was associated with delayed AIDS progression, while DC-SIGN -139C was associated with accelerated AIDS progression in HIV-1-infected Japanese hemophiliacs.

Genetic variation in the CCL18-CCL3-CCL4 chemokine gene cluster influences HIV Type 1 transmission and AIDS disease progression

CCL3 (MIP-1 alpha), CCL4 (MIP-1 beta), and CCL18 (DC-CK1/PARC/AMAC-1) are potent chemoattractants produced by macrophages, natural killer cells, fibroblasts, mast cells, CD4(+) T cells, and CD8(+) T cells. CCL3 and CCL4 are natural ligands for the primary human immunodeficiency virus type 1 (HIV-1) coreceptor CCR5 and are also known to activate and enhance the cytotoxicity of natural killer cells. Genomic DNAs from >3,000 participants enrolled in five United States-based natural-history cohorts with acquired immunodeficiency syndrome (AIDS) were genotyped for 21 single-nucleotide polymorphisms (SNPs) in a 47-kb interval on chromosome 17q12 containing the genes CCL3, CCL4, and CCL18. All 21 SNPs were polymorphic in African Americans (AAs), whereas 7 of the 21 had minor-allele frequencies <0.01 in European Americans (EAs). Substantial linkage disequilibrium was observed in a 37-kb interval containing 17 SNPs where many pairwise D' values exceeded 0.70 in both racial groups, but particularly in EAs. Four and three haplotype blocks were observed in AAs and EAs, respectively. Blocks were strongly correlated with each other, and common haplotype diversity within blocks was limited. Two significant associations are reported that replicate an earlier study. First, among AA members of the AIDS Link to the Intravenous Experience cohort of injection drug users, frequencies of three correlated SNPs covering 2,231 bp in CCL3 were significantly elevated among highly exposed, persistently HIV-1-uninfected individuals compared with HIV-1-infected seroconvertors (P = .02-.03). Second, seven highly correlated SNPs spanning 36 kb and containing all three genes were significantly associated with more-rapid disease progression among EAs enrolled in the Multicenter AIDS Cohort Study cohort (P = .01-.02). These results reiterate the importance of chemokine gene variation in HIV-1/AIDS pathogenesis and emphasize that localized linkage disequilibrium makes the identification of causal mutations difficult.