Mycobacterium tuberculosis H37Rv Strain Increases the Frequency of CD3+TCR+ Macrophages and Affects Their Phenotype, but Not Their Migration Ability

In mycobacterial infections, the number of cells from two newly discovered subpopulations of CD3+ myeloid cells are increased at the infection site; one type expresses the T cell receptor (CD3+TCRαβ+) and the other does not (CD3+TCRαβ−). The role of Mycobacterium tuberculosis (Mtb) virulence in generating these subpopulations and the ability of these cells to migrate remains unclear. In this study, monocyte-derived macrophages (MDMs) infected in vitro with either a virulent (H37Rv) or an avirulent (H37Ra) Mtb strain were phenotypically characterized based on three MDM phenotypes (CD3−, CD3+TCRαβ+, and CD3+TCRαβ−); then, their migration ability upon Mtb infection was evaluated. We found no differences in the frequency of CD3+ MDMs at 24 h of infection with either Mtb strain. However, H37Rv infection increased the frequency of CD3+TCRαβ+ MDMs at a multiplicity of infection of 1 and altered the expression of CD1b, CD1c, and TNF on the surface of cells from both the CD3+ MDM subpopulations; it also modified the expression of CCR2, CXCR1, and CCR7, thus affecting CCL2 and IL-8 levels. Moreover, H37Rv infection decreased the migration ability of the CD3− MDMs, but not CD3+ MDMs. These results confirm that the CD3+ macrophage subpopulations express chemokine receptors that respond to chemoattractants, facilitating cell migration. Together, these data suggest that CD3+ MDMs are a functional subpopulation involved in the immune response against Mtb.

Comparative efficacy of the novel diarylquinoline TBAJ-876 and bedaquiline against a resistant Rv0678 mutant in a mouse model of tuberculosis

Bedaquiline (BDQ, B) is the first-in-class diarylquinoline to be approved for treatment of tuberculosis (TB). Recent guidelines recommend its use in treatment of multidrug- and extensively drug-resistant (MDR/XDR-TB). The newly approved regimen combining BDQ with pretomanid and linezolid is the first 6-month oral regimen proven to be effective against MDR/XDR-TB. However, the emergence of BDQ resistance, primarily due to inactivating mutations in the Rv0678 gene encoding a repressor of the MmpS5-MmpL5 transporter, threatens to undermine the efficacy of new BDQ-containing regimens. Since the shift in MIC due to these mutations is relatively small (2-to-8x), safer and more potent diarylquinoline analogues may be more effective than BDQ. TBAJ-876, which is in phase 1 trials, has more potent in vitro activity and a superior pre-clinical safety profile than BDQ. Using a murine model of TB, we evaluated the dose-dependent activity of TBAJ-876 compared to BDQ against the wild-type H37Rv strain and an isogenic Rv0678 loss-of-function mutant. Though the mutation affected the MIC of both drugs, the MIC of TBAJ-876 against the mutant was 10-fold lower than that of BDQ. TBAJ-876 at doses ≥6.25 mg/kg had greater efficacy against both strains compared to BDQ at 25 mg/kg, when administered alone or in combination with pretomanid and linezolid. Likewise, no selective amplification of BDQ-resistant bacteria was observed at TBAJ-876 doses ≥6.25 mg/kg. These results indicate that replacing BDQ with TBAJ-876 may shorten the duration of TB treatment and be more effective in treating and preventing infections caused by Rv0678 mutants.

In Silico analysis of PE_PGRS20 (Rv1068c) protein in Mycobacterium tuberculosis H37Rv

The genetic makeup of Mycobacterium tuberculosis reveals the presence of an unknown repeat sequence of PE_PGRS family proteins that are responsible for antigenic variations and many unknown functions that includes necrosis of macrophage and apoptosis. The structure and function of these glycine-rich proteins can be predictable by homology modeling, the Ab-initio method, or by using different tools of bioinformatics. In this study, we selected, PE_PGRS20 (Rv1068c) an unknown PE_PGRS protein. We suggest that the PE_PGRS20 gene is linked with the others genes of the espACD operon which are the virulence factors in the M. tuberculosis H37Rv strain. The genes associated with this protein secretion system can perform the synthesis of a special type of fatty acid known as phthioceroldimycocerates (PDIM).Docking with different anti TB drugs shows binding with PE_PGRS20 protein which suggests that the target protein may involve in the drug resistance.

MDR and Pre-XDR Clinical Mycobacterium tuberculosis Beijing Strains: Assessment of Virulence and Host Cytokine Response in Mice Infectious Model

Mycobacterium tuberculosis Beijing genotype associated with drug resistance is a growing public health problem worldwide. The aim of this study was the assessment of virulence for C57BL/6 mice after infection by clinical M. tuberculosis strains 267/47 and 120/26, which belong to the modern sublineages B0/W148 and Central Asia outbreak of the Beijing genotype, respectively. The sublineages were identified by the analysis of the strains’ whole-genomes. The strains 267/47 and 120/26 were characterized as agents of pre-extensively drug-resistant (pre-XDR) and multidrug-resistant (MDR) tuberculosis, respectively. Both clinical strains were slow-growing in 7H9 broth compared to the M. tuberculosis H37Rv strain. The survival rates of C57BL/6 mice infected by 267/47, 120/26, and H37Rv on the 150th day postinfection were 10%, 40%, and 70%, respectively. Mycobacterial load in the lungs, spleen, and liver was higher and histopathological changes were more expressed for mice infected by the 267/47 strain compared to those infected by the 120/26 and H37Rv strains. The cytokine response in the lungs of C57BL/6 mice after infection with the 267/47, 120/26, and H37Rv strains was different. Notably, proinflammatory cytokine genes Il-1α, Il-6, Il-7, and Il-17, as well as anti-inflammatory genes Il-6 and Il-13, were downregulated after an infection caused by the 267/47 strain compared to those after infection with the H37Rv strain.

N-(Chlorobenzyl) Formamide as an Antituberculosis Agent from Multicomponent Reaction Synthesis

Tuberculosis (TB) is an infectious disease caused by M. tuberculosis. A new series of four benzylformamide with chloro substitution were synthesized by multicomponent reaction method and screened for antituberculosis activity against Mycobacterium tuberculosis H37Rv strain. This study was based on amidoalkylation reaction of aromatic-aldehyde, formamide and formic acid at 150oC to give a good yield of benzylformamide. Target compound were isolated, purificated, identified and characterized by GC-MS, FTIR, 1H-NMR, and 13C-NMR then the antituberculosis activity was examined by Microplate Alamar Blue Assay (MABA) and Middlebrook 7H9-7H11 medium in concentration series of 1000 – 1,954 μg/mL, and isoniazid as a positive control. Among the three derivative, N-(2,4-dichlorobenzyl) formamide has the most potential antituberculosis activity up to 500.0 L/mL.

Antimicrobial activity of Centella asiatica and Gigantochloa apus

Objectives Antibiotic treatments can create multi-drug resistance among several pathogens. There is a need for an antibiotic alternative to overcome this problem. In Indonesia, Centella asiatica (Asiatic pennywort) and Gigantochloa apus (string bamboo) are two common medicinal plants used to treat tuberculosis, diarrhea, and other symptoms. This study was done to compare the antimicrobial activity of C. asiatica and G. apus against five pathogenic bacteria, i.e., Mycobacterium tuberculosis H37Rv strain, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhi. Methods The ethanol extracts of C. asiatica, and G. apus shoot were obtained by using speed extractor, pressure, and temperature extraction. The phytochemical contents of each extract were screened. The ethanol extract’s antimycobacterial activity was determined using Lowenstein Jensen (LJ) medium and antibacterial activity was determined using Kirby–Bauer methods on Mueller Hinton agar (MHA). Results The phytochemical analysis showed that G. apus extract contains alkaloids and tannins, whereas C. asiatica extract contains flavonoids, alkaloids, saponins, and tannins. This study showed that G. apus inhibited the growth of M. tuberculosis H37Rv strain and S. typhi. C. asiatica showed antimicrobial activity against all pathogenic bacteria tested, except B. subtilis. Conclusions Both medicinal plants extract can inhibit the growth of five pathogenic bacteria tested, thus, have the potential as an alternative treatment, or complementary, to treat the pathogenic bacterial infection.

Synthesis of Substituted -N-(5-((7-Methyl-2-Oxo-2H-Chromen-4-yl)-Methyl)-1,3,4-Thiadiazol-2-yl)-Benzamide Derivatives Using TBTU As Coupling Agent And Their Evaluation For Anti Tubercular Activity

: Tuberculosis remains a highly infectious disease across the world. In the identification of new antitubercular agents, coumarin clubbed thiadiazole amides have been synthesized and evaluated for in vitro antitubercular activity. Due to the growing concern about chemicals and their impact on the environment, greener and faster reaction conditions needed to be incorporated. Therefore, we used TBTU as a coupling reagent for efficient and facile synthesis of substituted-N-(5-((7-methyl-2-oxo-2H-chromes-4-yl)-methyl)-1,3, 4 - thiadiazol-2-yl)-benzamide 4a-j with good yields up to 95% in mild reaction condition. All the synthesized compounds were evaluated in vitro for antitubercular activity against the H37Rv strain of M.Tuberculosis. Compounds 4c, 4f, and 4j were found active at 25 µg/mL against M. tb H37Rv. Electron withdrawing substituents present on aromatic side-chain showed promising anti-tubercular activity.

Synthesis, Characterization, Anti-Mycobacterial Evaluation and In-Silico Molecular Docking of Novel Isoxazole Clubbed Pyrimidine Derivatives

In the present research, we tend to ready a series of novel pyrimidine-linked isoxazole derivatives (11-20). The molecular structure and the elemental composition of these compounds were confirmed by spectroscopic studies and elemental analysis. MABA (Microplate alamar Blue Assay) assay was employed for assessing the antitubercular activity against the Mycobacterium tuberculosis H37Rv strain. Among the ten synthesized compounds, 18 and 20 showed excellent anti-tubercular activity than the reference (MIC-3.125 µg/ml) at 0.78 µg/mL. The compounds were found to possess good binding affinity than a standard against thymidylate kinase enzyme (PDB-1MRS) as evidenced by the molecular docking studies. Additionally, the bioactivity was conducted by Mol-inspiration software tool and the drug-likeness property was evaluated on Lipinski's rule of five by SCFBio online software. The lead compounds identified through these studies could be useful for the furtherance of the drug discovery process in the area of antitubercular research.

Polyurethane-functionalized starch nanocrystals as anti-tuberculosis drug carrier

Studies related to loading ability and delivery of clinically used first-line anti-tuberculosis drugs (ATDs) such as isoniazid, rifampicin, pyrazinamide and streptomycin on the surface of starch-derived bulk and nanopolyurethanes (SBPUs and SNPUs) as drug delivery systems (DDS) have been focused to minimise or remove the drug-associated adverse effects. The efficiencies of nanopolyurethanes obtained from the differently substituted cyclic aliphatic and aromatic isocyanates have been studied for drug loading and release purposes. Different advanced instrumental techniques analysed the structural and morphological properties, thermal stability and crystallinity of the starch nanopolyurethans. Average particle sizes ranging from 27.35–42.38 nm to 126.89–218.60 nm for starch nanopolyurethans, SNPU3i and SNPU4i, respectively, were determined by high-resolution transmission electron microscopy. Similarly, the loading efficiency of ATDs to the surfaces of SNPUs and SBPUs was observed in the range of 60–97% while ATDs-loaded SNPUs showed a sustainable release profile for all ATDs except for streptomycin. However, most SBPUs provided burst-release for all the above-mentioned ATDs in pH-dependent studies. The anti-tuberculosis assay against the Mycobacterium tuberculosis H37Rv strain revealed that streptomycin-loaded SNPU4i and isoniazid-loaded SNPU7i are approximately 42 and 7 times more active than the native streptomycin and isoniazid, respectively.

Antimycobacterial assessment and Microwave-assisted synthesis of 2-aryl-3-(4-methylphenylamino)thiazolidin-4-one derivatives

: This article reports the microwave-assisted synthesis, characterization, and evaluation of some -4-one derivatives (2a-2h) for their in-vitro antimycobacterial activities against Mycobacterium tuberculosis H37Rv strain by microplate Alamar blue assay (MABA) method. All these final compounds (2a-2h) were synthesized from Schiff’s bases, 1-arylidene-2-(4-methylphenyl)hydrazines (1a-1h), and thioglycolic acid by using zinc chloride as a catalyst. Compounds (1a-1h) were synthesized from the reaction of 4-methylhydrazine and appropriate aromatic aldehydes by Schiff’s reaction. Among the target compounds, 2-(4-ethoxyphenyl)-3-(4-methylarylamino)thiazolidin-4-one (2f) and 2-(4-ethylphenyl)-3-(4-methylarylamino)thiazolidin-4-one (2g) were promising with a minimum inhibitory concentration (MIC) of 12.5 μg/mL against M. tuberculosisH37Rv. Based on the preliminary results, compounds 2f and 2g were considered as lead compounds for the advanced design and development of antimycobacterial agents.