P2X7R Gene Polymorphisms are Associated with Increased Risk of Pulmonary Tuberculosis in the Tibetan Chinese Population

Research progress on genetic control of host susceptibility to tuberculosis

The "Lübeck disaster", twins studies, adoptees studies, and other epidemiological observational studies have shown that host genetic factors play a significant role in determining the host susceptibility to Mycobacterium tuberculosis infection and pathogenesis of tuberculosis. From linkage analyses to genome-wide association studies, it has been discovered that human leucocyte antigen (HLA) genes as well as non-HLA genes (such as SLC11A1, VDR, ASAP1 as well as genes encoding cytokines and pattern recognition receptors) are associated with tuberculosis susceptibility. To provide ideas for subsequent studies about risk prediction of MTB infection and the diagnosis and treatment of tuberculosis, we review the research progress on tuberculosis susceptibility related genes in recent years, focusing on the correlation of HLA genes and non-HLA genes with the pathogenesis of tuberculosis. We also report the results of an enrichment analysis of the genes mentioned in the article. Most of these genes appear to be involved in the regulation of immune system and inflammation， and are also closely related to autoimmune diseases.

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.

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.

Health Challenges of the Pacific Region: Insights From History, Geography, Social Determinants, Genetics, and the Microbiome

The Pacific region, also referred to as Oceania, is a geographically widespread region populated by people of diverse cultures and ethnicities. Indigenous people in the region (Melanesians, Polynesians, Micronesians, Papuans, and Indigenous Australians) are over-represented on national, regional, and global scales for the burden of infectious and non-communicable diseases. Although social and environmental factors such as poverty, education, and access to health-care are assumed to be major drivers of this disease burden, there is also developing evidence that genetic and microbiotic factors should also be considered. To date, studies investigating genetic and/or microbiotic links with vulnerabilities to infectious and non-communicable diseases have mostly focused on populations in Europe, Asia, and USA, with uncertain associations for other populations such as indigenous communities in Oceania. Recent developments in personalized medicine have shown that identifying ethnicity-linked genetic vulnerabilities can be important for medical management. Although our understanding of the impacts of the gut microbiome on health is still in the early stages, it is likely that equivalent vulnerabilities will also be identified through the interaction between gut microbiome composition and function with pathogens and the host immune system. As rapid economic, dietary, and cultural changes occur throughout Oceania it becomes increasingly important that further research is conducted within indigenous populations to address the double burden of high rates of infectious diseases and rapidly rising non-communicable diseases so that comprehensive development goals can be planned. In this article, we review the current knowledge on the impact of nutrition, genetics, and the gut microbiome on infectious diseases in indigenous people of the Pacific region.

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.

Genetic variation of rs7958311 in P2X7R gene is associated with the susceptibility and disease activity of ankylosing spondylitis

OBJECTIVES

To describe association between the genetic variation of inflammation-associated gene, P2X7R, and ankylosing spondylitis (AS) susceptibility.

METHODS

Four single nucleotide polymorphisms (SNPs) of P2 X 7 R gene were genotyped in 673 patients with AS and 687 healthy controls. Allele and genotype frequencies and different genetic models were performed to calculate ORs and 95% CIs, the demographic and clinical characteristics of patients were recorded. The data analyses were also conducted by sex.

RESULTS

Compared with controls, genetic variation in rs7958311 but not the other three SNPs was statistically significant in female patients (χ²=6.907, p=0.032). Specifically, the P2 X 7 R gene rs7958311 polymorphism A allele showed a protective effect in AS susceptibility (OR=0.704, p=0.049, p_FDR=0.061). In addition, female individuals with GA and/or AA genotypes had a lower risk of having AS compared with those with GG genotype (GA vs GG: OR=0.446, p=0.012, p_FDR=0.030; AA vs GG: OR=0.440, p=0.039, p_FDR=0.061; GA/AA vs GG: OR=0.445, p=0.009, p_FDR=0.030). Furthermore, individuals with A allele (ie, GA/AA vs GG) had a higher disease activity, including Bath Ankylosing Spondylitis Disease Activity Index (overall: Z=- 2.630, p=0.014; male: Z=- 2.243, p=0.025), Schober test (overall: Z=- 3.041, p<0.001; male: Z=- 2.243, p=0.025) and chest expansion (overall: Z=- 3.895, p=0.004; male: Z=- 2.403, p=0.016).

CONCLUSION

The allelic variation of rs7958311 SNP in P2X7R gene may have a protective effect on AS susceptibility in females and is associated with disease activity in male patients.

Associations of P2X7 Polymorphisms with the Odds of Tuberculosis: A Meta-Analysis

BACKGROUND

Recently, the roles of purinergic receptor P2X ligand-gated ion channel 7 (P2X7) polymorphisms in tuberculosis (TB) were analyzed by some pilot studies, but the results of these studies were inconsistent. We performed this study to better assess the relationship between P2X7 polymorphisms and the odds of TB.

METHODS

Eligible studies were searched in PubMed, MEDLINE, and Embase. Odds ratios and 95% confidence intervals were calculated.

RESULTS

A total of 21 studies were included for analyses. Significant associations with the odds of TB were detected for rs3751143 polymorphism in dominant (p = 0.01), recessive (p < 0.0001), additive (p = 0.0002), and allele models (p < 0.0001) in overall analyses. Further subgroup analyses based on the ethnicity of participants revealed that the rs1718119 polymorphism is significantly associated with the odds of TB in Asians and the rs3751143 polymorphism with the odds of TB in Caucasians.

CONCLUSION

Our findings indicate that rs1718119 polymorphism may serve as a potential biological marker of TB in Asians and the rs3751143 polymorphism as a potential biological marker of TB in Caucasians.

Association between TAP2 and SEC14L2 polymorphisms and pulmonary tuberculosis risk in the Tibetan Chinese population

AIM

Pulmonary tuberculosis (PTB) is an infectious disease with a high incidence worldwide. Previous genome-wide association studies have identified multiple susceptibility loci for pulmonary tuberculosis (PTB); however, validation of these findings is still needed.

METHODS

For this study, we recruited 300 subjects with PTB and 300 healthy subjects from a Tibetan population living in near or in Xi'an, China. Association analyses of single-nucleotide polymorphisms (SNPs) in TAP2 and SEC14L2 were performed with SPSS Statistics (version 17.0), SNPStats, Haploview (version 4.2), and SHEsis software.

RESULTS

We found a correction between one SNP (rs1061660) and PTB based on Chi-square or Fisher's exact tests. In the allelic model analysis, the SNPs rs1061660 in SEC14L2 gene increased PTB 1.32-fold risk (OR = 1.32, CI = 1.05-1.66, P = 0.017). In the genetic model analysis, the rs3819721 in TAP2 gene was associated with increased 1.65-fold risk in the co-dominant model and 1.67-fold risk in the over-dominant model, respectively. For the rs1061660 in SEC14L2 gene, we found it was associated with a 1.49-fold increase the risk of PTB in the dominant model and a 1.37-fold increase the risk of PTB in the log-additive model, respectively.

CONCLUSION

We found that two SNPs are associated with increased PTB risk in the Chinese Tibetan population.