Objectives miR-207 has been identified as being expressed in natural killer (NK) cell exosomes that play a role in disease progression; however, to date, there are no studies specifically linking miR-207 to tuberculosis (TB). Methods Bioinformatics methods employed for prediction, followed by a dual luciferase reporter assay to determine whether lysosome-associated membrane protein 2 (LAMP2) is targeted by miR-207. The experiments were divided into four groups using the liposome transfection method (OP-LAMP2 group: co-transfected with miR-207 mimics and LAMP2 overexpression plasmid; EP group: co-transfected with mimics NC and null-loaded plasmid; siLAMP2 group: transfected with siLAMP2; and siLAMP2-NC group: transfected with siLAMP2-NC). TB infection was modeled using H37Ra-infected Ana-1 cells. The impact of LAMP2 on intracellular mycobacterial load and clearance of extracellular residual mycobacteria were assessed by tuberculosis colony-forming unit counting. Flow cytometry was used to assess the total apoptosis rate. Real-time fluorescent quantitative PCR was conducted to determine the relative expression of LAMP2, apoptosis genes, pyroptosis genes, and autophagy genes. Western blot analysis was performed to measure the relative expression of LAMP2 proteins, apoptosis proteins, pyroptosis proteins, and autophagy proteins. Results Dual luciferase reporter assay test showed that there was a targeting relationship between LAMP2 and miR-207. The transfection model was successfully constructed under real-time fluorescent quantitative PCR and Western blot statistical analysis, and microscopic observation. The infection model was successfully established under microscopic observation. Colony forming unit counting revealed that the number of colonies in the OP-LAMP2 group was lower than that in the EP group, while the number of colonies in the siLAMP2 group was higher than that in the siLAMP2-NC group. Flow cytometry assay revealed that the total apoptosis in OP-LAMP2 group was lower than that in EP group, and the total apoptosis in siLAMP2 group was higher than that in siLAMP2-NC group. Real-time fluorescence quantitative PCR and Western blot analysis revealed that the relative expression of apoptosis and pyroptosis-related proteins and genes in the control group was lower in the OP-LAMP2 group compared to the EP group, and higher in the siLAMP2 group compared to the siLAMP2-NC group. Real-time fluorescence quantitative PCR detected that the relative expression of autophagy positively regulated genes Microtubule-associated protein 1 light chain 3(LC3)and Beclin1 in the OP-LAMP2 group was higher in the OP-LAMP2 group compared to the EP group, and lower in the siLAMP2 group compared to the siLAMP2-NC group, while the relative expression of negatively regulated autophagy genes followed the opposite trend to that of autophagy positively regulated genes. The relative expression of autophagy-related proteins was consistent with the trend of autophagy genes. Conclusions miR-207 enhances macrophage apoptosis, cellular pyroptosis and inhibits autophagy, promoting survival of Mycobacterium tuberculosis by targeting the autophagy-related protein LAMP2, thus offering a novel therapeutic direction for tuberculosis.
Lysosomal-Associated Membrane Protein 2/metabolism* ; MicroRNAs/metabolism* ; Mycobacterium tuberculosis/physiology* ; Autophagy/genetics* ; Humans ; Macrophages/metabolism* ; Apoptosis/genetics* ; Tuberculosis/metabolism* ; Cell Line ; Pyroptosis/genetics*

Objective To explore the effect of miR-582-5p on Mycobacterium tuberculosis (Mtb)-infected macrophages by regulating dual specificity phosphatase 1 (DUSP1). Methods THP-1 macrophages were divided into six groups: control group, Mtb group, inhibitor-NC group, miR-582-5p inhibitor group, miR-582-5p inhibitor+si-NC group, and miR-582-5p inhibitor+si-DUSP1 group. QRT-PCR was applied to detect the gene expression of miR-582-5p and DUSP1 in cells. ELISA kit was used to detect the levels of interferon γ (IFN-γ), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and interleukin 1β (IL-1β). CCK-8 method was applied to detect cell proliferation. Flow cytometry was applied to detect cell apoptosis rate. Western blot analysis was used to measure the protein expression levels of B-cell lymphoma 2 (Bcl2), Bcl2-associated X (BAX), and cleaved-caspase 3 (c-caspase-3) in cells. In addition, the target relationship between miR-582-5p and DUSP1 was verified. Results Compared with the control group, the expression of miR-582-5p, levels of IFN-γ, IL-6, TNF-α, IL-1β, bacterial load and OD450 values (24 h, 48 h), and the protein expression of Bcl2 in macrophages were higher in the Mtb group, while the mRNA expression of DUSP1, apoptosis rate, and the protein expression levels of c-caspase-3, BAX and DUSP1 were lower. Compared with the Mtb group and the inhibitor-NC group, the above-mentioned indicators in the miR-582-5p inhibitor group were partially reversed. Down-regulation of DUSP1 expression partially reversed the inhibitory effect of down-regulation of miR-582-5p expression on Mtb-infected macrophages. Conclusion Inhibiting the expression of miR-582-5p can up-regulate DUSP1, thereby inhibiting the proliferation and inflammatory response of Mtb-infected macrophages and promoting cell apoptosis.
Humans ; Macrophages/metabolism* ; Dual Specificity Phosphatase 1/metabolism* ; MicroRNAs/metabolism* ; Mycobacterium tuberculosis/physiology* ; Tuberculosis/microbiology* ; Apoptosis/genetics* ; THP-1 Cells ; Cell Proliferation/genetics* ; Interferon-gamma/genetics* ; Tumor Necrosis Factor-alpha/genetics* ; Interleukin-1beta/genetics*

Objective To study the effect of Mycobacterium tuberculosis (Mtb) Pro-Pro-Glu-59 (PPE59) protein on the biological function of Mycobacterium smegmatis (Ms) and the regulation of host cell immune response. Methods PPE59 gene fragment was obtained by PCR amplification, cloned into pALACE, constructed into recombinant pALACE-PPE59 vector, and electro-transformed into Ms. Western blot was applied to analyse PPE59 expression and subcellular localization. The survival of Ms_Vec and Ms_PPE59 under low acid (pH=3 and pH=5) conditions and active surface pressure sodium dodecyl sulfate (SDS) conditions and their intracellular survival in macrophages were analyzed. ELISA was used to detect the cytokine (IL-1β, IL-6, IL-12, TNF-α and IL-10) expression levels of Ms_Vec and Ms_PPE59 infected macrophages. Results PPE59 protein localized to the cell wall of Ms can enhance the acid-resistance and anti-SDS effect of Ms, which is conducive to the survival of Ms in macrophages. PPE59 significantly decreased the secretion levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-12 and TNF-α), and promoted the secretion levels of anti-inflammatory cytokine (IL-10). Conclusion PPE59 enhances the survival ability of Ms under low acid and SDS pressure and promotes its intracellular survival by regulating the cytokine secretion levels.
Mycobacterium smegmatis/metabolism* ; Macrophages/metabolism* ; Cytokines/metabolism* ; Mycobacterium tuberculosis/metabolism* ; Bacterial Proteins/metabolism* ; Animals ; Mice ; Antigens, Bacterial/metabolism*

Protein phosphorylation plays a key role in Mycobacterium tuberculosis, the pathogen of tuberculosis, holding promise as a new target of anti-tuberculosis drugs. We used M. smegmatis, a close relative of M. tuberculosis, as a model organism to study the protein phosphorylation at different growth phases. We identified 573 phosphorylated peptides and 816 phosphorylated sites of 385 proteins in the M. smegmatis samples at both logarithmic and stationary phases, and then established a comprehensive dataset of phosphorylated proteins in M. smegmatis. By comparing the expression levels of phosphorylated proteins between the logarithmic and the stationary phase with the selected ion monitoring (SIM) strategy, we verified 68 upregulated proteins involved in cell division and protein translation, and 69 downregulated proteins mainly involved in the tricarboxylic acid cycle pathway. The differentially expressed phosphorylated proteins were significantly enriched in important cellular cycle events such as cell elongation and division. The findings of this study provide proteome evidence for elucidating the phosphorylation in both M. smegmatis and M. tuberculosis.
Mycobacterium smegmatis/genetics* ; Bacterial Proteins/genetics* ; Phosphorylation ; Phosphoproteins/metabolism* ; Mycobacterium tuberculosis/growth & development* ; Proteome/metabolism* ; Proteomics

Mycolic acids (MAs), i.e. 2-alkyl, 3-hydroxy long-chain fatty acids, are the hallmark of the cell envelope of Mycobacterium tuberculosis and are related with antibiotic resistance and host immune escape. Nowadays, they've become hot target of new anti-tuberculosis drugs. There are two main methods to detect MAs, ¹⁴C metabolic labeling thin-layer chromatography (TLC) and liquid chromatograph mass spectrometer (LC-MS). However, the user qualification of ¹⁴C or the lack of standards for LC-MS hampered the easy use of this method. TLC is a common way to analyze chemical substance and can be used to analyze MAs. In this study, we used tetrabutylammonium hydroxide and methyl iodide to hydrolyze and formylate MAs from mycobacterium cell wall. Subsequently, we used diethyl ether to extract methyl mycolate. By this method, we can easily extract and analyze MA in regular biological labs. The results demonstrated that this method could be used to compare MAs of different mycobacterium in different growth phases, MAs of mycobacteria treated by anti-tuberculosis drugs or MAs of mycobacterium mutants. Therefore, we can use this method as an initial validation for the changes of MAs in researches such as new drug screening without using radioisotope or when the standards are not available.
Mycolic Acids/metabolism* ; Chromatography, Thin Layer ; Mycobacterium tuberculosis ; Fatty Acids ; Antitubercular Agents/pharmacology*

Objectives To develop a multi-stage and multi-epitope vaccine, which consists of epitopes from the early secretory and latency-associated antigens of Mycobacterium tuberculosis (MTB). Methods The B-cell, cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes of 12 proteins were predicted using an immunoinformatics. The epitopes with antigenicity, without cytotoxicity and sensitization, were further screened to construct the multi-epitope vaccine. Furthermore, the proposed vaccine underwent physicochemical properties analysis and secondary structure prediction as well as 3D structure modeling, refinement and validation. Then the refined model was docked with TLR4. Finally, an immune simulation of the vaccine was carried out. Results The proposed vaccine, which consists of 12 B-cell, 11 CTL and 12 HTL epitopes, had a flexible and stable globular conformation as well as a thermostable and hydrophilic structure. A stable interaction of the vaccine with TLR4 was confirmed by molecular docking. The efficiency of the candidate vaccine to trigger effective cellular and humoral immune responses was assessed by immune simulation. Conclusion A multi-stage multi-epitope MTB vaccine construction strategy based on immunoinformatics is proposed, which is expected to prevent both active and latent MTB infection.
Mycobacterium tuberculosis/metabolism* ; Molecular Docking Simulation ; Toll-Like Receptor 4 ; Epitopes, T-Lymphocyte/chemistry* ; Epitopes, B-Lymphocyte/chemistry* ; Vaccines, Subunit/chemistry* ; Computational Biology/methods*

The adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter, IrtAB, plays a vital role in the replication and viability of Mycobacterium tuberculosis (Mtb), where its function is to import iron-loaded siderophores. Unusually, it adopts the canonical type IV exporter fold. Herein, we report the structure of unliganded Mtb IrtAB and its structure in complex with ATP, ADP, or ATP analogue (AMP-PNP) at resolutions ranging from 2.8 to 3.5 Å. The structure of IrtAB bound ATP-Mg2+ shows a "head-to-tail" dimer of nucleotide-binding domains (NBDs), a closed amphipathic cavity within the transmembrane domains (TMDs), and a metal ion liganded to three histidine residues of IrtA in the cavity. Cryo-electron microscopy (Cryo-EM) structures and ATP hydrolysis assays show that the NBD of IrtA has a higher affinity for nucleotides and increased ATPase activity compared with IrtB. Moreover, the metal ion located in the TM region of IrtA is critical for the stabilization of the conformation of IrtAB during the transport cycle. This study provides a structural basis to explain the ATP-driven conformational changes that occur in IrtAB.
Siderophores/metabolism* ; Iron/metabolism* ; Mycobacterium tuberculosis/metabolism* ; Cryoelectron Microscopy ; Adenosine Triphosphate/metabolism* ; ATP-Binding Cassette Transporters

Objective To explore the therapeutic effect of ethambutol tablets (EMB) on pulmonary tuberculosis (PTB) in rats and whether the action mechanism of EMB is related to Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway. Methods Sixty SD rats were assigned into a control group,a PTB group,a PTB+EMB group (30 mg/kg),and a PTB+EMB+Colivelin (JAK/STAT pathway activator) group (30 mg/kg+1 mg/kg) via the random number table method,with 15 rats in each group.The rats in other groups except the control group were injected with 0.2 ml of 5 mg/ml Mycobacterium tuberculosis suspension to establish the PTB model.After the modeling,the rats were administrated with corresponding drugs for 4 consecutive weeks (once a day).On days 1,14,and 28 of administration,the body weights of rats were measured and the Mycobacterium tuberculosis colonies were counted.Hematoxylin-eosin staining was carried out to detect the pathological changes in the lung tissue.Enzyme-linked immunosorbent assay was employed to measure the levels of interleukin(IL)-6,tumor necrosis factor-α (TNF-α),IL-1β,and interferon-γ (IFN-γ) in the serum.Flow cytometry was used to determine the levels of T lymphocyte subsets CD3+,CD4+,CD8+,and CD4+/CD8+.The 16S rRNA sequencing was performed to detect the relative abundance of the intestinal microorganisms.Western blotting was employed to determine the expression of the proteins in the JAK/STAT pathway. Results Compared with the control group,the modeling of PTB reduced the rat body weight (on days 14 and 28),increased Mycobacterium tuberculosis colonies,caused severe pathological changes in the lung tissue,and elevated the levels of IL-6,TNF-α,and IL-1β in serum and CD8+.Moreover,the modeling increased the relative abundance of Bacteroides,Peptococcus,Clostridium,Actinomyces,Lactobacillus,Verrucomicrobium,and Veillonella in the intestine,up-regulated the protein levels of phosphorylated JAK2 and phosphorylated STAT3 in the lung tissue,and lowered the levels of CD3+,CD4+,CD4+/CD8+,and IFN-γ levels (all P<0.001).Compared with the PTB group,PTB+EMB increased the rat body weight (on days 14 and 28),reduced Mycobacterium tuberculosis colonies,alleviated the pathological damage in lung tissue,lowered the levels of IL-6,TNF-α,and IL-1β in serum and CD8+.Moreover,the treatment decreased the relative abundance of Bacteroides,Peptococcus,Clostridium,Actinomyces,Lactobacillus,Verrucomicrobium,Veillonella in the intestine,down-regulated the protein levels of phosphorylated JAK2 and phosphorylated STAT3 in the lung tissue,and elevated the levels of CD3+,CD4+,CD4+/CD8+,and IFN-γ (all P<0.001).Colivelin weakened the alleviation effect of EMB on PTB (all P<0.001). Conclusion EMB can inhibit the JAK/STAT signaling pathway to alleviate the PTB in rat.
Animals ; Body Weight ; Ethambutol/pharmacology* ; Interferon-gamma/pharmacology* ; Interleukin-6/metabolism* ; Janus Kinases/pharmacology* ; Mycobacterium tuberculosis/metabolism* ; RNA, Ribosomal, 16S ; Rats ; Rats, Sprague-Dawley ; STAT Transcription Factors/pharmacology* ; Signal Transduction ; Tablets/pharmacology* ; Tuberculosis, Pulmonary/metabolism* ; Tumor Necrosis Factor-alpha/metabolism*

Objective: To evaluate the serological diagnostic value of Mycobacterium (M.) tuberculosis four new antigens Rv0432, Rv0674, Rv1566c and Rv1547. Methods:Rv0432, Rv0674, Rv1566c and Rv1547 were amplified from M. tuberculosis strain H37Rv genomic DNA by using PCR, among which Rv1547 was divided into two segments for amplification (Rv1547-1 and Rv1547-2). The segments were cloned into expression vector PET-32a while the recombinant proteins were purified by affinity chromatography. Serums were incubated with BL21 (DE3) proteins. Antibodies IgG against M. tuberculosis were tested with 151 serum samples (41 healthy people and 110 TB patients) by using ELISA. The diagnostic efficiency of antigens was analyzed by means of receiver operating characteristic curve. Difference of the objective proteins in TB patients and healthy controls was compared by t-test. Results: Recombinant antigens Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2 were successfully expressed and purified. Results from ELISA showed that the sensitivity, specificity, positive predictive value, negative predictive value, Youden index and area under the curve of Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2, as 43.64%-92.73%, 80.49%-92.68%, 0.92-0.94, 0.38-0.80, 0.363-0.732 and 0.649-0.915. All the objective proteins showed significantly higher antibody levels in TB patients, when compared to the healthy controls (P<0.000 1). Conclusion: The newly identified antigens Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2 all performed well when being used for TB serological diagnosis, thus were expected to be new candidate antigens used for TB diagnosis.
Antigens, Bacterial/genetics* ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G ; Mycobacterium tuberculosis/metabolism* ; Polymerase Chain Reaction ; ROC Curve ; Recombinant Proteins ; Sensitivity and Specificity ; Serologic Tests/methods* ; Tuberculosis/genetics*

We evaluate the performance of Xpert MTB/RIF for the diagnosis of extrapulmonary tuberculosis (EPTB) in China. The performance of Xpert was evaluated compared to the composite reference standard (CRS), drug susceptibility testing (DST), and imaging examination. The overall sensitivity and specificity of Xpert were 64.1% (195/304) and 100% (24/24), respectively, using CRS as the gold standard. The sensitivity was significantly higher than that of culture for pus (P<0.05). The proportion of EPTB-positive cases diagnosed by imaging was two times more than that diagnosed using Xpert; however, 6 out of 19 cases may have been overdiagnosed by imaging. Compared to phenotypic DST, the sensitivity and specificity of Xpert were 80% (12/15) and 100% (75/75), respectively. Considering its high sensitivity and specificity, Xpert MTB/RIF may be used as a rapid initial test for EPTB diagnosis, and may also support a quicker decision on the treatment regimen. The combination of imaging and Xpert testing could provide high efficiency and accurate diagnosis of suspected EPTB.
Bacterial Proteins ; genetics ; metabolism ; China ; DNA-Directed RNA Polymerases ; genetics ; metabolism ; Diagnostic Tests, Routine ; instrumentation ; methods ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis ; drug effects ; genetics ; isolation & purification ; metabolism ; Retrospective Studies ; Rifampin ; pharmacology ; Sensitivity and Specificity ; Sputum ; Tuberculosis ; Tuberculosis, Pulmonary ; diagnosis ; microbiology