[New vaccines against tuberculosis]

Roles of the m6A methyltransferases METTL3, METTL14, and WTAP in pulmonary tuberculosis

Objective

The aim of the current study was to investigate the contributing role of gene variation and transcription levels among the m6A methyltransferases METTL3, METTL14, and WTAP in pulmonary tuberculosis (PTB).

Methods

A case-control study including 461 PTB patients and 467 normal controls was designed for genotyping. Three SNPs in METTL3 (rs1061027, rs1139130, rs1061026), three SNPs in METTL14 (rs62328061, rs4834698, rs1064034), and two SNPs in WTAP (rs1853259, rs11752345) were genotyped via the SNPscan™ technique. METTL3, METTL14, and WTAP transcription levels were determined in 78 PTB patients and 86 controls via quantitative real-time reverse-transcription PCR.

Results

Frequencies of the METTL14 rs62328061 GG genotype, WTAP rs11752345 CT genotype, and T allele were significantly increased in PTB patients compared to controls. An increased risk of rs62328061 was detected in a recessive model, and a decreased risk of rs11752345 was detected in a dominant model in the PTB group. METTL3 gene variation was not associated with PTB risk. The METTL3 rs1139130 GG genotype was significantly increased with drug resistance, and the G allele was significantly decreased with drug-induced liver injury in PTB patients. A reduced frequency of the METTL14 rs62328061 G allele was associated with leukopenia, a reduced frequency of the WTAP rs11752345 T allele was associated with sputum smear positivity, and a higher frequency of the METTL14 rs4834698 TC genotype was evident in PTB patients with hypoproteinemia. Compared to controls, METTL3, METTL14, and WTAP transcription levels in PTB patients were significantly decreased, and the level of WTAP was increased in PTB patients with drug resistance. METTL3 level was negatively associated with erythrocyte sedimentation rate and aspartate aminotransferase, and METTL14 level was negatively correlated with alanine aminotransferase and aspartate aminotransferase.

Conclusion

METTL14 rs62328061 and WTAP rs11752345 variants were associated with the genetic background of PTB, and METTL3, METTL14, and WTAP levels were abnormally decreased, suggesting that these m6A methyltransferases may play important roles in PTB.

Association Between Genetic Polymorphisms of lncRNA NEAT1 and Pulmonary Tuberculosis Risk, Clinical Manifestations in a Chinese Population

Background

Recent studies have shown that abnormal expression of lncRNA NEAT1 is associated with the progression of pulmonary tuberculosis (PTB). The aim of our study was to analyze the relationship between single nucleotide polymorphisms (SNPs) of NEAT1 gene and susceptibility to PTB.

Methods

Four SNPs (rs2239895, rs3741384, rs3825071, rs512715) in NEAT1 gene were genotyped in 479 patients with PTB and 476 controls by improved multiple ligase detection reaction (iMLDR) in a Chinese population.

Results

We found no significant differences in allele and genotype frequencies of NEAT1 gene rs2239895, rs3741384, rs3825071, rs512715 between PTB patients and controls (all P > 0.05). There was no statistically significant association between genotype frequency distribution of dominant model, as well as recessive model, and genetic susceptibility to PTB patients (all P > 0.05). The TT genotype, T allele frequencies of rs3825071 were significantly increased in sputum smear-positive PTB patients when compared to sputum smear-negative PTB patients (P = 0.010, P = 0.003, respectively). Haplotype analysis shown that NEAT1 haplotype frequency was not associated with PTB susceptibility.

Conclusion

NEAT1 gene polymorphisms were not associated with the risk of PTB in Chinese population, and rs3825071 polymorphism might be related to sputum smear-positive in PTB patients.

The double-edged sword of Tregs in M tuberculosis, M avium, and M absessus infection

Immunity against different Mycobacteria species targeting the lung requires distinctly different pulmonary immune responses for bacterial clearance. Many parameters of acquired and regulatory immune responses differ quantitatively and qualitatively from immunity during infection with Mycobacteria species. Nontuberculosis Mycobacteria species (NTM) Mycobacterium avium- (M avium), Mycobacterium abscessus-(M abscessus), and the Mycobacteria species Mycobacterium tuberculosis-(Mtb). Herein, we discuss the potential implications of acquired and regulatory immune responses in the context of animal and human studies, as well as future directions for efforts to treat Mycobacteria diseases.

LncRNA NEAT1 participates in inflammatory response in macrophages infected by mycobacterium tuberculosis through targeted regulation of miR-377-3p

Background Tuberculosis (TB) is a very serious public health problem in the world at present. The incidence rate is rising continuously. Once it develops to the middle and late stage, it can cause serious tissue damage and necrosis, directly threatening the life and health of patients. Because of its high incidence, high infectivity and high mortality, clinical research on TB has never stopped. Previous studies have confirmed the effect of macrophages on mycobacterium tuberculosis (MTB) infection, and its regulatory mechanism has not yet been fully clarified. Objective To analyze the effects of NEAT1 and miR-377-3p on macrophages infected by MTB and provide new reference for the diagnosis and treatment of TB in the future. Methods The pulmonary TB patients admitted to our hospital from July 2017 to July 2019 and the healthy cases at the same time were selected as the research objects for prospective analysis. In addition, THP-1 cells and mycobacterium tuberculosis H37Ra were purchased to construct macrophages infected by H37Ra, and the effects of NEAT1 and miR-377-3p on macrophages and their relationship with inflammatory factors were analyzed. Results NEAT1 was highly expressed in pulmonary TB patients and miR-377-3p was poorly expressed (p < 0.05). The concentrations of inflammatory factors in serum of patients with pulmonary TB were significantly higher than those in healthy cases (P < 0.001). After infection with H37Ra, the inflammatory factors in macrophages increased significantly (p < 0.001), while miR-377-3p decreased (p < 0.001). Inhibition of NEAT1 and increase of miR-377-3p could decrease inflammatory factors and proliferation ability of cells, and increase apoptosis rate (p < 0.001). The double luciferase reporter assay showed that the fluorescence activity of NEAT1-WT was inhibited by the transfection of miR-377-3pmimics (P < 0.001). Conclusion NEAT1 participates in inflammatory response in macrophages infected by MTB through targeted regulation of miR-377-3p.

RNA Sensing of Mycobacterium tuberculosis and Its Impact on TB Vaccination Strategies

Tuberculosis (TB) is still an important global threat and although the causing organism has been discovered long ago, effective prevention strategies are lacking. Mycobacterium tuberculosis (MTB) is a unique pathogen with a complex host interaction. Understanding the immune responses upon infection with MTB is crucial for the development of new vaccination strategies and therapeutic targets for TB. Recently, it has been proposed that sensing bacterial nucleic acid in antigen-presenting cells via intracellular pattern recognition receptors (PRRs) is a central mechanism for initiating an effective host immune response. Here, we summarize key findings of the impact of mycobacterial RNA sensing for innate and adaptive host immunity after MTB infection, with emphasis on endosomal toll-like receptors (TLRs) and cytosolic sensors such as NLRP3 and RLRs, modulating T-cell differentiation through IL-12, IL-21, and type I interferons. Ultimately, these immunological pathways may impact immune memory and TB vaccine efficacy. The novel findings described here may change our current understanding of the host response to MTB and potentially impact clinical research, as well as future vaccination design. In this review, the current state of the art is summarized, and an outlook is given on how progress can be made.