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ABSTRACT Background: Autophagy can inhibit the survival of intracellular microorganisms including Mycobacterium tuberculosis (Mtb), and the PI3K/AKT/mTOR pathway plays a crucial role. This study investigated the association between PI3K/AKT/mTOR pathway autophagy-related gene polymorphisms and pulmonary tuberculosis (PTB) susceptibility. Methods: KEGG pathway and gene ontology (GO) databases were searched for genes belonging to the PI3K/AKT/mTOR and autophagy pathways. Thirty SNPs in nine genes were identified and tested for their associations with tuberculosis in 130 patients with PTB and 271 controls. We constructed genetic risk scores (GRSs) and divided the participants into 3 subgroups based on their GRSs:0-5, 6-10, and 11-16. Results: This analysis revealed that the AKT1 (rs12432802), RPTOR (rs11654508, rs12602885, rs2090204, rs2589144, and rs2672897), and TSC2 (rs2074969) polymorphisms were significantly associated with PTB risk. A decreasing trend was observed (P trend 0.020), in which a lower GRS was associated with a higher risk of PTB ([6-10] vs. [0-5]: OR (95%CI) 0.590 (0.374-0.931); [11-16] vs. [0-5]: OR (95%CI) 0.381 (0.160-0.906)). Conclusions: Polymorphisms in AKT1, RPTOR, and TSC2 may influence susceptibility to PTB.
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ABSTRACT Although tuberculosis (TB) is a serious public health concern, we still don't understand why only 10% of people infected will develop the disease. Apoptosis plays a role in the interaction of Mycobacterium tuberculosis (Mtb) with the human host and it may be modified by subtle alterations in the B-cell lymphoma 2 (BCL2) gene, an anti-apoptotic regulatory element. Therefore, we investigated whether there is an association between BCL2 polymorphisms and susceptibility to TB by analyzing 130 TB cases, 108 subjects with latent TB infection (LTBI), and 163 healthy controls (HC). Logistic regression was used to calculate odds ratios (ORs) and 95% confidential intervals (95% CIs) for possible associations between single nucleotide polymorphisms (SNPs) in BCL2 and the risk of tuberculosis. We found that the G allele of rs80030866 (OR=0.62, 95%CI:0.42-0.91, P=0.015), and also the G allele of rs9955190 (OR=0.58, 95%CI:0.38-0.88, P=0.011) were less frequent in the TB group compared with the LTBI group. In addition, individuals with rs2551402 CC genotype were more likely to have LTBI than those with AA genotype (OR=2.166, 95%CI:1.046-4.484, P=0.037). Our study suggests that BCL2 gene polymorphisms may be correlated with susceptibility to both TB and LTBI.
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La técnica de espoligotipaje y el método de unidades repetitivas micobacterianas interdiseminadas y número variable de repetidos tándem (MIRU-VNTR) 24 loci se emplean para estudiar la epidemiología molecular de tuberculosis. En el presente trabajo evaluamos la discriminación del método MIRU-VNTR 24 loci solo y en asociación con espoligotipaje en aislados clínicos de M. tuberculosis en Venezuela, la diversidad alélica de los 24 loci, y el poder discriminativo para la combinación de 24 y 15 loci, 12 loci tradicionales (12t), aquellos con más alta diversidad alélica y una nueva combinación que denominamos 12 inv. Se estudiaron 104 cepas de diferentes linajes y 431 cepas de la familia Latin-America y Mediterráneos (LAM). Los loci 4052, 2163b, 424 y 2996 presentaron la más alta diversidad alélica. Las tasas de agrupamiento de MIRU-VNTR 24 loci, espoligotipaje y MIRU-VNTR combinado con espoligotipaje para 104 aislados fueron de 18,27%, 71,15% y 14,4%, respectivamente, mientras que para cepas LAM fue de 43,2%, 95,8% y 37,4%. Las combinaciones de 15, 12inv y 4 loci MIRU-VNTR mas discriminativos, fueron más discriminatorios que 12t. Las tasas de agrupamiento para 15 y 12inv MIRU VNTR acoplados a espoligotipaje en los 104 aislados fueron de 21% y 23%, mientras que para cepas LAM fue de 52% y 46% respectivamente. El número de patrones diferentes fue similar para 12inv y 15 loci. Se propone el uso de un número reducido de loci MIRU-VNTR informativos acoplado a espoligotipaje para estudios de la transmisión de la tuberculosis en Venezuela.
The techniques of spoligotyping and mycobacterial interspersed repetitive unit and variable-number tandem repeat typing with 24 loci (MIRU-VNTR-24), have been used to study the molecular epidemiology of tuberculosis. The aim of this study was: to evaluate the discriminative power of MIRU-VNTR 24 loci alone and in association with spoligotyping in clinical isolates of M. tuberculosis in Venezuela; the allelic diversity of the 24 loci; and the discriminative power for the combination of 24 and 15 loci, 12 traditional loci (12t), those with higher allelic diversity and a new combination named 12inv. We analyzed one set of 104 strains of different lineages and a second set of 431 strains belonging to the Latin-America and Mediterranean lineage (LAM) that is predominant in Venezuela. The determination of allelic diversity showed that 4052, 2163b, 424 y 2996 are highly discriminative. Clustering rates of MIRU-VNTR 24 loci, spoligotyping and MIRU-VNTR combined with spoligotyping for 104 isolates were 18.27%, 71.15% and 14.4%, respectively, whereas with the 431 LAM strains the values were 43.2 %, 95.8% and 37.4%. MIRU-VNTR combinations of 15, 12inv and 4 loci were more discriminatory than 12t. Clustering rates for MIRU-VNTR 15 and 12inv loci coupled with spoligotyping in the 104 isolated was 21% and 23%, while for LAM strains was 52% and 46% respectively. The number of different genetics patterns for 15 and 12inv loci were similar. In conclusion, we propose the use of a small number of informative loci MIRU-VNTR coupled to spoligotyping to investigate the transmission of tuberculosis in Venezuela.