A meta-analysis of P2X7 gene-762T/C polymorphism and pulmonary tuberculosis susceptibility

P2X7 1513A/C loss-of-function polymorphism and active tuberculosis disease in a cohort of Egyptian population: a pilot study

Background

Tuberculosis (TB) is a multifactorial disease, and increasing evidence shows that genetic variants in regulating genes of immune response confer susceptibility to active TB at the individual level. We aimed to identify the contribution of P2X7 receptor 1513A/C genetic polymorphisms to different clinical forms of active tuberculosis in a cohort of Egyptian population.

Methods

A case–control study that enrolled 25 newly diagnosed pulmonary TB (PTB) patients by positive sputum for AFB or positive culture, 25 extrapulmonary TB (EPTB) diagnosed by pathological/bacteriological/immunological studies and 25 healthy controls. A blood sample was taken before starting of therapy for P2X7 1513A/C polymorphism genotyping using PCR-restriction fragment length polymorphism.

Results

Fifty-two percent of the participants were in the third decade with equal gender distribution. P2X7 receptor 1513AA (homozygote wild), AC (heterozygote) and CC (homozygote mutant) genotypes were identified. AC and CC genotypes distribution were significantly more frequent in the active TB cases (either PTB or EPTB) rather than controls (p < 0.05). Further, P2X7 1513A/C genotypes’ distribution did not associate with old TB or gender (p > 0.05), but significantly associated with history of smoking (x2 trend analysis p = 0.036).

Conclusions

There is positive association between P2X7 receptor 1513A/C polymorphism and active tuberculosis in the Egyptians.

Associations Between the Purinergic Receptor P2X7 and Leprosy Disease

Leprosy is an infectious disease still highly prevalent in Brazil, having been detected around 27,863 new cases in 2019. Exposure to Mycobacterium leprae may not be sufficient to trigger the disease, which seems to be influenced by host immunogenetics to determine resistance or susceptibility. The purinergic receptor P2X7 plays a crucial role in immunity, inflammation, neurological function, bone homeostasis, and neoplasia and is associated with several infectious and non-infectious diseases. Here, we first compare the P2RX7 expression in RNA-seq experiments from 16 leprosy cases and 16 healthy controls to establish the magnitude of allele-specific expression for single-nucleotide polymorphisms of the gene P2RX7 and to determine the level of gene expression in healthy and diseased skin. In addition, we also evaluated the association of two P2RX7 single-nucleotide polymorphisms (c.1513A>C/rs3751143 and c.1068A>G/rs1718119) with leprosy risk. The expression of P2RX7 was found significantly upregulated at macrophage cells from leprosy patients compared with healthy controls, mainly in macrophages from lepromatous patients. Significant risk for leprosy disease was associated with loss function of rs3751143 homozygous mutant CC [CC vs. AA: p = 0.001; odds ratio (OR) = 1.676, 95% CI = 1.251–2.247] but not with heterozygous AC (AC vs. AA: p = 0.001; OR = 1.429, 95% CI = 1.260–1.621). Contrary, the polymorphic A allele from the gain function of rs1718119 was associated with protection for the development of leprosy, as observed in the dominant model (AA + AG × GG p = 0.0028; OR = 0.03516; CI = 0.1801–0.6864). So, our results suggest that the functional P2X7 purinergic receptor may exert a key role in the Mycobacterium death inside macrophages and inflammatory response, which is necessary to control the disease.

The role of P2X7 receptor in infection and metabolism: Based on inflammation and immunity

The P2X7 receptor (P2X7R) is a ligand-gated receptor belonging to the P2 receptor family. It is distributed in various tissues of the human body and is involved in regulating the physiological functions of tissues and cells to affect the occurrence and development of diseases. Unlike all other P2 receptors, the P2X7 receptor is mainly expressed in immune cells and can be activated not only by extracellular nucleotides but also by non-nucleotide substances which act as positive allosteric modulators. In this review, we comprehensively describe the role of the P2X7 receptor in infection and metabolism based on its role as an important regulator of inflammation and immunity, and briefly introduce the structure and general function of the P2X7 receptor. These provide a clear knowledge framework for the study of the P2X7 receptor in human health. Targeting the P2X7 receptor may be an effective method for the treatment of inflammatory and immune diseases. And its role in microbial infection and metabolism may be the main direction for in-depth research on the P2X7 receptor in the future.

P2RX7 at the Host-Pathogen Interface of Infectious Diseases

The P2X7 receptor (P2RX7) is an important molecule that functions as a danger sensor, detecting extracellular nucleotides from injured cells and thus signaling an inflammatory program to nearby cells. It is expressed in immune cells and plays important roles in pathogen surveillance and cell-mediated responses to infectious organisms. There is an abundance of literature on the role of P2RX7 in inflammatory diseases and the role of these receptors in host-pathogen interactions. Here, we describe the current knowledge of the role of P2RX7 in the host response to a variety of pathogens, including viruses, bacteria, fungi, protozoa, and helminths. We describe in vitro and in vivo evidence for the critical role these receptors play in mediating and modulating immune responses. Our observations indicate a role for P2X7 signaling in sensing damage-associated molecular patterns released by nearby infected cells to facilitate immunopathology or protection. In this review, we describe how P2RX7 signaling can play critical roles in numerous cells types in response to a diverse array of pathogens in mediating pathogenesis and immunity to infectious agents.

Purinergic Receptors: Elucidating the Role of these Immune Mediators in HIV-1 Fusion

Purinergic receptors are inflammatory mediators activated by extracellular nucleotides released by dying or injured cells. Several studies have described an important role for these receptors in HIV-1 entry, particularly regarding their activity on HIV-1 viral membrane fusion. Several reports identify purinergic receptor antagonists that inhibit HIV-1 membrane fusion; these drugs are suspected to act through antagonizing Env-chemokine receptor interactions. They also appear to abrogate activity of downstream mediators that potentiate activation of the NLRP3 inflammasome pathway. Here we review the literature on purinergic receptors, the drugs that inhibit their function, and the evidence implicating these receptors in HIV-1 entry.

Association between P2X7 Polymorphisms and Susceptibility to Tuberculosis: An Updated Meta-Analysis of Case-Control Studies

Background and Objectives: Several studies inspected the impact of P2X7 polymorphisms on individual susceptibility to tuberculosis (TB), but the findings are still controversial and inconclusive. To achieve a more precise estimation, we conducted a meta-analysis of all eligible studies on the association between P2X7 polymorphisms and TB risk. Materials and Methods: Relevant studies were identified by searching the PubMed, Web of Science, Scopus and Google scholar databases up to November 2018. Twenty-four full-text articles were included in our meta-analysis. The strength of association between P2X7 polymorphisms and TB risk was evaluated by odds ratios (ORs) and 95% confidence intervals (95% CIs) under five genetic models. Results: The findings of this meta-analysis revealed that the rs3751143 variant significantly increased the risk of TB in heterozygous codominant (OR = 1.44, 95%CI = 1.17-1.78, p = 0.0006, AC vs. AA), homozygous codominant (OR = 1.87, 95% CI = 1.40-2.49, p = 0.0004, CC vs. AA), dominant (OR = 1.50, 95% CI = 1.22-1.85, p = 0.0002, AC + CC vs. AA), recessive (OR = 1.61, 95% CI = 1.25-2.07, p = 0.001, CC vs. AC + AA), and allele (OR = 1.41, 95% CI = 1.19-1.67, p < 0.0001, C vs. A) genetic models. Stratified analysis showed that rs3751143 increased the risk of pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) in all genetic models. Furthermore, the rs3751143 increased risk of TB in the Asian population. The findings did not support an association between the rs2393799, rs1718119, rs208294, rs7958311, and rs2230911 polymorphisms of P2X7 and TB risk. Conclusions: The findings of this meta-analysis suggest that P2X7 rs3751143 polymorphism may play a role in susceptibility to TB in the Asian population. More well-designed studies are required to elucidate the exact role of P2X7 polymorphisms on TB development.

Purinergic P2X7 receptor functional genetic polymorphisms are associated with the susceptibility to osteoporosis in Chinese postmenopausal women

Osteoporosis (OP) is a major public health problem worldwide. Genetic factors are considered to be major contributors to the pathogenesis of OP. The purinergic P2X7 receptor (P2X7R) has been shown to play a role in the regulation of osteoblast and osteoclast activity and has been considered as an important candidate gene for OP. A case-control study was performed to investigate the associations of functional single nucleotide polymorphisms (SNPs) in the P2X7R gene (rs2393799, rs7958311, rs1718119, rs2230911, and rs3751143) with susceptibility to OP in 400 Chinese OP patients and 400 controls. Results showed that rs3751143 was associated with OP; in particular, carriers of the C allele and CC/(AC + CC) genotypes were at a higher risk of OP, but no significant association of rs2230911, rs7958311, rs1718119, and rs2393799 with OP risk was observed. Analysis of the haplotypes revealed one haplotype (rs1718119G-rs2230911G-rs3751143C) that appeared to be a significant "risk" haplotype with OP. The rs3751143 polymorphism was associated with osteoclast apoptosis; ATP-induced caspase-1 activity of osteoclasts with AC and CC genotypes is lower than that of osteoclasts with AA genotype in vitro. The findings suggest that the P2X7R rs3751143 functional polymorphism might contribute to OP susceptibility in Chinese postmenopausal women.

The Role of Host Genetics (and Genomics) in Tuberculosis

Familial risk of tuberculosis (TB) has been recognized for centuries. Largely through studies of mono- and dizygotic twin concordance rates, studies of families with Mendelian susceptibility to mycobacterial disease, and candidate gene studies performed in the 20th century, it was recognized that susceptibility to TB disease has a substantial host genetic component. Limitations in candidate gene studies and early linkage studies made the robust identification of specific loci associated with disease challenging, and few loci have been convincingly associated across multiple populations. Genome-wide and transcriptome-wide association studies, based on microarray (commonly known as genechip) technologies, conducted in the past decade have helped shed some light on pathogenesis but only a handful of new pathways have been identified. This apparent paradox, of high heritability but few replicable associations, has spurred a new wave of collaborative global studies. This review aims to comprehensively review the heritability of TB, critically review the host genetic and transcriptomic correlates of disease, and highlight current studies and future prospects in the study of host genomics in TB. An implicit goal of elucidating host genetic correlates of susceptibility to Mycobacterium tuberculosis infection or TB disease is to identify pathophysiological features amenable to translation to new preventive, diagnostic, or therapeutic interventions. The translation of genomic insights into new clinical tools is therefore also discussed.

The evolution of P2X7 antagonists with a focus on CNS indications

The P2X7 receptor is an ATP-gated nonselective cation channel that has been linked to a number of inflammatory diseases. Activation of the P2X7 receptor by elevated levels of ATP results in the release of proinflammatory cytokines and elevated levels of these cytokines has been associated with a variety of disease states. A number of research groups in both industry and academia have explored the identification of P2X7R antagonists as therapeutic agents. Much of this early effort focused on the treatment of diseases related to peripheral inflammation and resulted in several clinical candidates, none of which were advanced to market. The emerging role of the P2X7 receptor in neuroinflammation and related diseases has resulted in a shift in medicinal chemistry efforts toward the development of centrally penetrant antagonists. This review will highlight the biology supporting the role of P2X7 in diseases related to neuroinflammation and review the recent medicinal chemistry efforts to identify centrally penetrant antagonists.

Association Between P2RX7 Gene and Hepatocellular Carcinoma Susceptibility: A Case-Control Study in a Chinese Han Population

Background

Hepatocellular carcinoma (HCC) is one of the most common types of liver cancer. It is hypothesized that P2RX7 genetic polymorphisms have strong association with HCC susceptibility. Therefore, a case-control study was designed and performed to verify the association between P2RX7 gene polymorphisms and HCC susceptibility.

Material/Methods

A total of 646 subjects were recruited in our study, including 323 HCC patients and 323 healthy controls. Five gene polymorphisms, −762C>T (rs2393799), 946G>A (rs28360457), 1513A>C (rs3751143), 1068G>A (rs1718119), and 1096C>G (rs2230911), were selected. Odds ratio (ORs) and 95% confidence interval (CI) were used to quantify the association between P2RX7 gene polymorphisms and the susceptibility to HCC. All tests were performed using SPSS 20 and a 2-sided P value of less than 0.05 was considered to be statistically significant.

Results

Our results suggest that allelic frequencies of these 5 SNPs all conformed to Hardy-Weinberg equilibrium (HWE). There was no significant difference in genotype and allele distributions of −762C>T and 1096C>G between the case group and the control group. However, an increased risk of HCC was associated with 946G>A (A vs. G: OR=1.48, 95%CI=1.09–2.01, P=0.013; GA+AA vs. GG: OR=1.46, 95%CI=1.03–2.07, P=0.033). A similar increased risk was associated with 1513A>C polymorphism (C vs. A: OR=1.37, 95%CI=1.05–1.79, P=0.021; AC+CC vs. AA: OR=1.40, 95%CI=1.01–1.93, P=0.041). On the other hand, a decreased risk of HCC was associated with gene polymorphism of 1068G>A (A vs. G: OR=0.68, 95%CI=0.51–0.91, P=0.010; GA+AA vs. GG: OR=0.68, 95%CI=0.49–0.96, P=0.027; AA vs. GG: OR=0.42, 95%CI=0.18–0.99, P=0.048).

Conclusions

Our results suggest that 3 of the 5 polymorphisms of P2RX7 described above (1513A>C, 946G>A, and 1068G>A) are significantly associated with HCC susceptibility in a Chinese Han population. Studies with larger sample sizes are recommended to confirm whether our results will be applicable to different ethnic populations in China.

Purinergic Receptors: Key Mediators of HIV-1 Infection and Inflammation

Human immunodeficiency virus type 1 (HIV-1) causes a chronic infection that afflicts more than 30 million individuals worldwide. While the infection can be suppressed with potent antiretroviral therapies, individuals infected with HIV-1 have elevated levels of inflammation as indicated by increased T cell activation, soluble biomarkers, and associated morbidity and mortality. A single mechanism linking HIV-1 pathogenesis to this inflammation has yet to be identified. Purinergic receptors are known to mediate inflammation and have been shown to be required for HIV-1 infection at the level of HIV-1 membrane fusion. Here, we review the literature on the role of purinergic receptors in HIV-1 infection and associated inflammation and describe a role for these receptors as potential therapeutic targets.

The association between CD209 gene polymorphisms and pulmonary tuberculosis susceptibility: a meta-analysis

AIM

Three common polymorphisms in CD209 gene (-336A/G, -871A/G and -139G/A) have been reportedly associated with pulmonary tuberculosis risk. However, the findings from different studies were inconsistent. Therefore, we conducted a comprehensive meta-analysis to determine the association between CD209 gene polymorphisms and pulmonary tuberculosis susceptibility.

METHODS

The PubMed, SCI and Elsevier were searched up to April 18, 2015 for studies on the association of CD209 gene polymorphisms and pulmonary tuberculosis. Pooled odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated in a fixed-effects or random-effects model.

RESULTS

Twelve case-control studies with 3114 cases and 3088 controls were included. For -871A/G mutation, significant decreased pulmonary tuberculosis risk was observed in allele model (G vs. A: P = 0.009; OR = 0.70, 95% CI = 0.54-0.92), heterozygous model (AG vs. AA: P = 0.009; OR = 0.59, 95% CI = 0.40 to 0.88) and dominant model (AG+GG vs. AA: p =0.01; OR = 0.61, 95% CI = 0.42 to 0.89). For -336A/G polymorphism, no associations were found in all genetic models. In the subgroup analysis by ethnicity, statistical association was observed for Asians in GG vs. AA (P = 0.04; OR = 2.31, 95% CI = 1.05-5.09). No significant association was identified between -139G/A variation and pulmonary tuberculosis risk.

CONCLUSIONS

This meta-analysis provides evidences that CD209 gene -871A/G is associated with decreased susceptibility to pulmonary tuberculosis in overall population; -336A/G polymorphism is associated with increased susceptibility of pulmonary tuberculosis in Asians. However, the -139G/A polymorphism is not associated with susceptibility to pulmonary tuberculosis.