An Overview of Genetic Information of Latent Mycobacterium tuberculosis

Mapping Crohn's Disease Pathogenesis with Mycobacterium paratuberculosis: A Hijacking by a Stealth Pathogen

Mycobacterium avium ssp. paratuberculosis (MAP) has been implicated in the development of Crohn's disease (CD) for over a century. Similarities have been noted between the (histo)pathological presentation of MAP in ruminants, termed Johne's disease (JD), and appearances in humans with CD. Analyses of disease presentation and pathology suggest a multi-step process occurs that consists of MAP infection, dysbiosis of the gut microbiome, and dietary influences. Each step has a role in the disease development and requires a better understanding to implementing combination therapies, such as antibiotics, vaccination, faecal microbiota transplants (FMT) and dietary plans. To optimise responses, each must be tailored directly to the activity of MAP, otherwise therapies are open to interpretation without microbiological evidence that the organism is present and has been influenced. Microscopy and histopathology enables studies of the mycobacterium in situ and how the associated disease processes manifest in the patient e.g., granulomas, fissuring, etc. The challenge for researchers has been to prove the relationship between MAP and CD with available laboratory tests and methodologies, such as polymerase chain reaction (PCR), MAP-associated DNA sequences and bacteriological culture investigations. These have, so far, been inconclusive in revealing the relationship of MAP in patients with CD. Improved and accurate methods of detection will add to evidence for an infectious aetiology of CD. Specifically, if the bacterial pathogen can be isolated, identified and cultivated, then causal relationships to disease can be confirmed, especially if it is present in human gut tissue. This review discusses how MAP may cause the inflammation seen in CD by relating its known pathogenesis in cattle, and from examples of other mycobacterial infections in humans, and how this would impact upon the difficulties with diagnostic tests for the organism.

PathTracer Comprehensively Identifies Hypoxia-Induced Dormancy Adaptations in Mycobacterium tuberculosis

Mining large-scale data to discover biologically relevant information remains a challenge despite the rapid development of bioinformatics tools. Here, we have developed a new tool, PathTracer, to identify biologically relevant information flows by mining genome-wide protein-protein interaction networks following integration of gene expression data. PathTracer successfully mines interactions between genes and traces the most perturbed paths of perceived activities under the conditions of the study. We further demonstrated the utility of this tool by identifying adaptation mechanisms of hypoxia-induced dormancy in Mycobacterium tuberculosis (Mtb).

Interleukin 4 gene polymorphisms and the risk of tuberculosis: A meta-analysis

BACKGROUND

Interleukin-4 (IL-4) is implicated in the progression of tuberculosis (TB); however, these results remain controversial.

OBJECTIVES

This meta-analysis examined the relationship between IL and 4 polymorphisms (-589C/T, +4221C > A, and -33C/T) and the risk of TB.

METHODS

A retrospective database analysis was conducted using the CNKI and PubMed databases. Using fixed- and random-effects models, we calculated the combined odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We identified 14 articles related to this topic, and theresultsshowed that the IL-4 -589C/T polymorphism didnotinfluencethe risk of TB. However,in subgroupanalyses we found that the IL-4 -589C/T polymorphism was associated with the risk of TB inCaucasians (recessive modelOR = 2.54, 95% CI = 1.30-4.96). In our study, the IL-4--33C/T polymorphism was not associated with the risk of TB. The IL-4 + 4221C > A polymorphism was associated with the risk of TB (recessive model: OR = 1.40, 95% CI = 1.07-1.83).

CONCLUSION

This meta-analysis showed that the IL-4 -589C/T polymorphism was associated with TB risk in Caucasian populations, and the IL-4 + 4221C > A polymorphism is associated with TB risk.

Latent tuberculosis and computational biology: A less-talked affair

Tuberculosis (TB) is a pervasive and devastating air-borne disease caused by the organisms belonging to the Mycobacterium tuberculosis (Mtb) complex. Currently, it is the global leader in infectious disease-related death in adults. The proclivity of TB to enter the latent state has become a significant impediment to the global effort to eradicate TB. Despite decades of research, latent tuberculosis (LTB) mechanisms remain poorly understood, making it difficult to develop efficient treatment methods. In this review, we seek to shed light on the current understanding of the mechanism of LTB, with an accentuation on the insights gained through computational biology. We have outlined various well-established computational biology components, such as omics, network-based techniques, mathematical modelling, artificial intelligence, and molecular docking, to disclose the crucial facets of LTB. Additionally, we highlighted important tools and software that may be used to conduct a variety of systems biology assessments. Finally, we conclude the article by addressing the possible future directions in this field, which might help a better understanding of LTB progression.

Correlation between polymorphism of vitamin D receptor TaqI and susceptibility to tuberculosis: An update meta-analysis

BACKGROUND

To investigate the association between TaqI polymorphism of the vitamin D receptor gene and tuberculosis (TB).

METHODS

A systematic search was performed in PubMed, Embase, Web of Science, Elsevier Science Direct, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang, and Chongqing VIP databases for case-control study on TaqI gene polymorphism and TB susceptivity. Quality assessment of studies was performed using the Newcastle-Ottawa Scale for the methodological assessment of case-control studies, and R 4.0.5 software was used for the meta-analysis.

RESULTS

Among the 243 selected articles, 27 in the meta-analysis. The meta-analysis showed that the TaqI gene polymorphism allene gene model (t vs T, odds ratio [OR]: 1.12, 95% confidence interval [CI]: 0.99-1.27); dominant model (tt + tT vs TT, OR: 1.12, 95% CI: 0.98-1.29); recessive model (tt vs tT + TT, OR: 1.25, 95% CI: 1.03-1.51); codominant A (tt vs TT, OR: 1.37, 95% CI: 1.00-1.87); codominant B (tT vs TT, OR: 1.09, 95% CI: 0.99-1.19). And subgroup dominant model (tt + tT vs TT, OR: 1.27, 95% CI: 1.03-1.55) in Indianas, recessive model (tt vs tT + TT, OR: 1.49, 95% CI: 1.05-2.11) in Iranians, co-dominant B (tT vs TT, OR: 1.28, 95% CI: 1.03-1.59; OR: 1.42, 95% CI: 1.05-1.93) in Indianas and Iranians.

CONCLUSION

This meta-analysis suggests a significant association between TB and the risk of TaqI in Iranians and Indians, but the vitamin D receptor polymorphism TaqI was not associated with Chinese. Thus, validation studies will be required to confirm these findings.

In Silico Drug Discovery Strategies Identified ADMET Properties of Decoquinate RMB041 and Its Potential Drug Targets against Mycobacterium tuberculosis

The highly adaptive cellular response of Mycobacterium tuberculosis to various antibiotics and the high costs for clinical trials, hampers the development of novel antimicrobial agents with improved efficacy and safety. Subsequently, in silico drug screening methods are more commonly being used for the discovery and development of drugs, and have been proven useful for predicting the pharmacokinetics, toxicities, and targets, of prospective new antimicrobial agents. In this investigation we used a reversed target fishing approach to determine potential hit targets and their possible interactions between M. tuberculosis and decoquinate RMB041, a propitious new antituberculosis compound. Two of the 13 identified targets, Cyp130 and BlaI, were strongly proposed as optimal drug-targets for dormant M. tuberculosis, of which the first showed the highest comparative binding affinity to decoquinate RMB041. The metabolic pathways associated with the selected target proteins were compared to previously published molecular mechanisms of decoquinate RMB041 against M. tuberculosis, whereby we confirmed disrupted metabolism of proteins, cell wall components, and DNA. We also described the steps within these pathways that are inhibited and elaborated on decoquinate RMB041’s activity against dormant M. tuberculosis. This compound has previously showed promising in vitro safety and good oral bioavailability, which were both supported by this in silico study. The pharmacokinetic properties and toxicity of this compound were predicted and investigated using the online tools pkCSM and SwissADME, and Discovery Studio software, which furthermore supports previous safety and bioavailability characteristics of decoquinate RMB041 for use as an antimycobacterial medication.

IMPORTANCE This article elaborates on the mechanism of action of a novel antibiotic compound against both, active and dormant Mycobacterium tuberculosis and describes its pharmacokinetics (including oral bioavailability and toxicity). Information provided in this article serves useful during the search for drugs that shorten the treatment regimen for Tuberculosis and cause minimal adverse effects.

Revisiting tuberculosis screening: An insight to complementary diagnosis and prospective molecular approaches for the recognition of the dormant TB infection in human and cattle hosts

Tuberculosis (TB) is defined as a chronic infection in both human and cattle hosts and many subclinical cases remain undetected. After the pathogen is inhaled by a host, phagocyted bacilli can persist inside macrophages surviving intracellularly. Hosts develop granulomatous lesions in the lungs or lymph nodes, limiting infection. However, bacilli become persister cells. Immunological diagnosis of TB is performed basically by routine tuberculin skin test (TST), and in some cases, by ancillary interferon-gamma release assay (IGRA). The concept of human latent TB infection (LTBI) by M. tuberculosis is recognized in cohorts without symptoms by routine clinical diagnostic tests, and nowadays IGRA tests are used to confirm LTBI with either active or latent specific antigens of M. tuberculosis. On the other hand, dormant infection in cattle by M. bovis has not been described by TST or IGRA testing as complications occur by cross-reactive immune responses to homolog antigens of environmental mycobacteria or a false-negative test by anergic states of a wained bovine immunity, evidencing the need for deciphering more specific biomarkers by new-generation platforms of analysis for detection of M. bovis dormant infection. The study and description of bovine latent TB infection (boLTBI) would permit the recognition of hidden animal infection with an increase in the sensitivity of routine tests for an accurate estimation of infected dairy cattle. Evidence of immunological and experimental analysis of LTBI should be taken into account to improve the study and the description of the still neglected boLTBI.