Host-mediated ubiquitination of a mycobacterial protein suppresses immunity.

Mycobacterium tuberculosis is an intracellular pathogen that uses several strategies to interfere with the signalling functions of host immune molecules. Many other bacterial pathogens exploit the host ubiquitination system to promote pathogenesis1,2, but whether this same system modulates the ubiquitination of M. tuberculosis proteins is unknown. Here we report that the host E3 ubiquitin ligase ANAPC2-a core subunit of the anaphase-promoting complex/cyclosome-interacts with the mycobacterial protein Rv0222 and promotes the attachment of lysine-11-linked ubiquitin chains to lysine 76 of Rv0222 in order to suppress the expression of proinflammatory cytokines. Inhibition of ANAPC2 by specific short hairpin RNA abolishes the inhibitory effect of Rv0222 on proinflammatory responses. Moreover, mutation of the ubiquitination site on Rv0222 impairs the inhibition of proinflammatory cytokines by Rv0222 and reduces virulence during infection in mice. Mechanistically, lysine-11-linked ubiquitination of Rv0222 by ANAPC2 facilitates the recruitment of the protein tyrosine phosphatase SHP1 to the adaptor protein TRAF6, preventing the lysine-63-linked ubiquitination and activation of TRAF6. Our findings identify a previously unrecognized mechanism that M. tuberculosis uses to suppress host immunity, and provide insights relevant to the development of effective immunomodulators that target M. tuberculosis.

Nuclear cGAS suppresses DNA repair and promotes tumorigenesis.

Accurate repair of DNA double-stranded breaks by homologous recombination preserves genome integrity and inhibits tumorigenesis. Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that activates innate immunity by initiating the STING-IRF3-type I IFN signalling cascade1,2. Recognition of ruptured micronuclei by cGAS links genome instability to the innate immune response3,4, but the potential involvement of cGAS in DNA repair remains unknown. Here we demonstrate that cGAS inhibits homologous recombination in mouse and human models. DNA damage induces nuclear translocation of cGAS in a manner that is dependent on importin-α, and the phosphorylation of cGAS at tyrosine 215-mediated by B-lymphoid tyrosine kinase-facilitates the cytosolic retention of cGAS. In the nucleus, cGAS is recruited to double-stranded breaks and interacts with PARP1 via poly(ADP-ribose). The cGAS-PARP1 interaction impedes the formation of the PARP1-Timeless complex, and thereby suppresses homologous recombination. We show that knockdown of cGAS suppresses DNA damage and inhibits tumour growth both in vitro and in vivo. We conclude that nuclear cGAS suppresses homologous-recombination-mediated repair and promotes tumour growth, and that cGAS therefore represents a potential target for cancer prevention and therapy.

Mouse nerve growth factor suppresses neuronal apoptosis in valproic acid-induced autism spectrum disorder rats by regulating the phosphoinositide-3-kinase/serine/threonine kinase signaling pathway.

BACKGROUND: Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders characterized by deficits in social communication and restrictive behaviors. Mouse nerve growth factor (mNGF), a neurotrophic factor, is critical for neuronal growth and survival, and the mNGF treatment is considered a promising therapy for neurodegeneration. In light of this, we aimed to evaluate the effect of mNGF on neurological function in ASD. METHODS: An ASD rat model was established by intraperitoneal injection of valproic acid (VPA). Social behavior, learning, and memory of the rats were measured. TdT-mediated dUTP Nick-end labeling and Nissl assays were performed to detect neuronal apoptosis and survival in the hippocampus and prefrontal cortex. Apoptosis-related proteins and oxidative stress markers were detected. RESULTS: mNGF improved locomotor activity, exploratory behavior, social interaction, and spatial learning and memory in VPA-induced ASD rats. In the hippocampus and prefrontal cortex, mNGF suppressed neuronal apoptosis, increased the number of neurons, superoxide dismutase, and glutathione levels, and decreased reactive oxygen species, nitric oxide, TNF-α, and IL-1ß levels compared with the VPA group. In addition, mNGF increased the levels of Bcl-2, p-phosphoinositide-3-kinase (PI3K), and p-serine/threonine kinase (Akt), and decreased the levels of Bax and cleaved caspase-3, while the PI3K inhibitor LY294002 reversed these effects. CONCLUSION: These data suggest that mNGF suppressed neuronal apoptosis and ameliorated the abnormal behaviors in VPA-induced ASD rats, in part, by activating the PI3K/Akt signaling pathway.

Sensing of mycobacterial arabinogalactan by galectin-9 exacerbates mycobacterial infection.

Mycobacterial arabinogalactan (AG) is an essential cell wall component of mycobacteria and a frequent structural and bio-synthetical target for anti-tuberculosis (TB) drug development. Here, we report that mycobacterial AG is recognized by galectin-9 and exacerbates mycobacterial infection. Administration of AG-specific aptamers inhibits cellular infiltration caused by Mycobacterium tuberculosis (Mtb) or Mycobacterium bovis BCG, and moderately increases survival of Mtb-infected mice or Mycobacterium marinum-infected zebrafish. AG interacts with carbohydrate recognition domain (CRD) 2 of galectin-9 with high affinity, and galectin-9 associates with transforming growth factor ß-activated kinase 1 (TAK1) via CRD2 to trigger subsequent activation of extracellular signal-regulated kinase (ERK) as well as induction of the expression of matrix metalloproteinases (MMPs). Moreover, deletion of galectin-9 or inhibition of MMPs blocks AG-induced pathological impairments in the lung, and the AG-galectin-9 axis aggravates the process of Mtb infection in mice. These results demonstrate that AG is an important virulence factor of mycobacteria and galectin-9 is a novel receptor for Mtb and other mycobacteria, paving the way for the development of novel effective TB immune modulators.

A Meta-Analysis on the Impact of Prenatal and Early Childhood Antimicrobial Use on Autism Spectrum Disorders.

OBJECTIVE: To investigate the impact of prenatal and early childhood antimicrobial use on autism spectrum disorders (ASD). DATA SOURCES: We searched PubMed and Embase databases for relevant studies from inception to August 2022. STUDY SELECTION AND DATA EXTRACTION: Peer-reviewed, observational studies were all acceptable. Raw data were extracted into a predefined worksheet and quality analysis was performed using the Newcastle-Ottawa Scale. DATA SYNTHESIS: Nineteen studies were identified in the meta-analysis. Prenatal antimicrobial exposure was not associated with ASD (P = 0.06 > 0.05), whereas early childhood antimicrobial exposure was associated with an increased odds ratio of ASD (OR = 1.17, 95% CI = [1.08-1.27], P value < 0.001). The sibling-matched analysis, with a very limited sample size, suggested that neither prenatal (P = 0.47 > 0.05) nor early childhood (P = 0.13 > 0.05) antimicrobial exposure was associated with ASD. Medical professionals may need to take the possible association into consideration when prescribing an antimicrobial in children. CONCLUSIONS: Early childhood antimicrobial exposure could increase the incidence of ASD. In future studies, it would be necessary to control for confounding factors, such as genetic factors, parenteral age at birth, or low birthweight, to further validate the association.

TCHis mitigate oxidative stress and improve abnormal behavior in a prenatal valproic acid-exposed rat model of autism.

Troxerutin is known for its anti-inflammatory and antioxidative effects in nerve impairment. The purpose of this study is to investigate the effect of troxerutin and cerebroprotein hydrolysate injections (TCHis) on prenatal valproic acid (VPA)-exposed rats. The VPA was administered to pregnant rats on gestational day 12.5 to induce a model of autism. The offspring were given the treatment of TCHis on postnatal day (PND) 21-50. On PND 43-50, the behavioral analysis of offspring was performed after the treatment of TCHis for 1 h. On PND 50, the offspring were harvested and the brains were collected. The hippocampus and prefrontal cortex were isolated for relevant biochemical detections. The administration of TCHis increased pain sensitivity and improved abnormal social behaviors in prenatal VPA-exposed rats. Prenatal exposure of VPA induced neuronal loss and apoptosis, enhanced reactive oxygen species (ROS) production, and promoted oxidative stress in hippocampus and prefrontal cortex, whereas these effects were reversed by the postnatal treatment of TCHis. In addition, postnatal administration of TCHis ameliorated mitochondrial function in hippocampus and prefrontal cortex of prenatal VPA-exposed rats. This study concluded that postnatal treatment of TCHis reduced oxidative stress and ameliorated abnormal behavior in a prenatal VPA-induced rat model of autism.

NH2NH-MOF: a reaction matrix for the specific determination of small aldehydes by MALDI-MS.

Efficient determination of aldehydes by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is hampered mainly by the low mass and unstable nature of analytes. In the present work, we propose a combined strategy of a reactive metal-organic framework (MOF) matrix for the derivatization and detection of aldehydes. A novel reactive MOF matrix (NH2NH-MOF) was synthesized in two steps. First, NR3+-MOF was synthesized via Cu2+ and the quaternary amine ligand 4,4'-bipyridinium, 1,1″-(1,2-ethanediyl)bis-, dibromide (PyEtBr). Then, -NHNH2 was introduced to NR3+-MOF through electrostatic adsorption between the -NR3+ and -HSO3- of 4-hydrazinylbenzenesulfonic acid to synthesize NH2NH-MOF. The acid-base chemistry of NH2NH-MOF led to uniform cocrystallization of the aldehyde-matrix mixtures and helped to achieve the detection of low-weight aldehydes with good relative standard deviations (RSDs = 0.07-12.35%). It was confirmed that this strategy can accurately quantify formaldehyde, valeraldehyde, and benzaldehyde with good linearity (r > 0.97). Furthermore, this strategy was applied to quantitatively detect benzaldehyde in wastewater, thus showing potential applications in environmental pollutant detection.

Core-shell MOF@COFs used as an adsorbent and matrix for the detection of nonsteroidal anti-inflammatory drugs by MALDI-TOF MS.

A core-shell material (UiO@TapbTp) has been developed as an adsorbent and matrix to detect nonsteroidal anti-inflammatory drugs (NSAIDS) by matrix laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in complex samples. The hybrid material is prepared by growing covalent organic framework (COF, TapbTp) layers in situ on an amino-modified metal-organic framework (MOF, UiO-66-NH2). The combination of the MOF and COF overcomes their individual shortcomings and integrates both of their advantages. Compared with the bare COF and MOF, the core-shell composite exhibits improved enrichment ability and matrix performance. With the help of pre-enrichment under optimized conditions, the limits of detection (LODs) for ketoprofen, naproxen, and aspirin are reduced by nearly 1000 times, with values of 0.001 mg L-1, 0.010 mg L-1, and 0.001 mg L-1, respectively, and the relative standard deviations (RSDs) are all below 12.35%. The good recoveries (84.8-118%) in (spiked) saliva and environmental water sample further verify the applicability of the method in complex samples.

Latency-Optimal Computational Offloading Strategy for Sensitive Tasks in Smart Homes.

In smart homes, the computational offloading technology of edge cloud computing (ECC) can effectively deal with the large amount of computation generated by smart devices. In this paper, we propose a computational offloading strategy for minimizing delay based on the back-pressure algorithm (BMDCO) to get the offloading decision and the number of tasks that can be offloaded. Specifically, we first construct a system with multiple local smart device task queues and multiple edge processor task queues. Then, we formulate an offloading strategy to minimize the queue length of tasks in each time slot by minimizing the Lyapunov drift optimization problem, so as to realize the stability of queues and improve the offloading performance. In addition, we give a theoretical analysis on the stability of the BMDCO algorithm by deducing the upper bound of all queues in this system. The simulation results show the stability of the proposed algorithm, and demonstrate that the BMDCO algorithm is superior to other alternatives. Compared with other algorithms, this algorithm can effectively reduce the computation delay.

A deletion in the RD105 region confers resistance to multiple drugs in Mycobacterium tuberculosis.

BACKGROUND: The emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb), especially those that are multidrug resistant poses a serious threat to global tuberculosis control. However, the mechanism underlying the occurrence of drug resistance against more than one drug is poorly understood. Given that the Beijing/W strains are associated with outbreaks and multidrug resistance, they may harbor a genetic advantage and provide useful insight into the disease. One marker found in all Beijing/W Mtb strains is a deletion of RD105 region that results in a gene fusion, Rv0071/74, with a variable number (3-9 m) of VDP (V: Val, D: Asp; P: Pro) repeats (coded by gtggacccg repeat sequences) at the N-terminal. Here, we report that this variable number of VDP repeats in Rv0071/74 regulates the development of multidrug resistance. RESULTS: We collected and analyzed 1255 Beijing/W clinical strains. The results showed that the number of VDP repeats in Rv0071/74 was related to the development of multidrug resistance, and the deletion of Rv0071/74-9 m from Beijing/W clinical strain restored drug susceptibility. Rv0071/74-9 m also increased resistance to multiple drugs when transferred to different mycobacterial strains. Cell-free assays indicate that the domain carrying 4-9 VDP repeats (4-9 m) showed a variable binding affinity with peptidoglycan and Rv0071/74 cleaves peptidoglycan. Furthermore, Rv0071/74-9 m increased cell wall thickness and reduced the intracellular concentration of antibiotics. CONCLUSIONS: These findings not only identify Rv0071/74 with VDP repeats as a newly identified multidrug resistance gene but also provide a new model for the development of multiple drug resistance.

Notch4 Negatively Regulates the Inflammatory Response to Mycobacterium tuberculosis Infection by Inhibiting TAK1 Activation.

Tuberculosis, caused by Mycobacterium tuberculosis infection, remains a global threat to human health, but knowledge of the molecular mechanisms underlying the pathogenesis of tuberculosis is still limited. Although Notch4, a member of the Notch receptor family, is involved in the initiation of mammary tumors, its function in M. tuberculosis infection remains unclear. In this study, we found that Notch4-deficient mice were more resistant to M. tuberculosis infection, with a much lower bacterial burden and fewer pathological changes in the lungs. Notch4 inhibited M. tuberculosis-induced production of proinflammatory cytokines by interaction with TAK1 and inhibition of its activation. Furthermore, we found that Notch intracellular domain 4 prevented TRAF6 autoubiquitination and suppressed TRAF6-mediated TAK1 polyubiquitination. Finally, Notch inhibitors made mice more resistant to M. tuberculosis infection. These results suggest that Notch4 is a negative regulator of M. tuberculosis-induced inflammatory response, and treatment with a Notch inhibitor could serve as a new therapeutic strategy for tuberculosis.

An ultrasensitive electrochemiluminescent sensor based on a pencil graphite electrode modified with CdS nanorods for detection of chlorogenic acid in honeysuckle.

In this paper, a novel and ultrasensitive electrochemiluminescent sensor employing a solvothermal-synthesized CdS nanorod-modified pencil graphite electrode (CdS/PGE) for the determination of chlorogenic acid (CA) is fabricated. In the first step, the PGE surface is modified using CdS nanorods. In the next step, the developed electrode is used to detect CA using a electrochemiluminescent (ECL) technique, in which potassium persulfate (K2 S2 O8 ) served as a co-reactant. The possible ECL mechanism is investigated, and the influences of pH and cyclic voltammetric scanning rate on the signal response are studied. The ECL intensity decreases quantitatively in relation to the concentration of the target molecule. Under optimized conditions, the linear correlation between the quenched ECL intensity and the logarithm of CA concentration is observed in the range from 2 × 10-9 to 8 × 10-7  mol L-1 with a limit of detection of 1 × 10-9  mol L-1 . This proposed method is applied to the analysis of CA in honeysuckle flower, giving recoveries of 99-107%. The experimental results demonstrate that this ECL sensor shows good stability and reproducibility.

Pyrosequencing for rapid detection of tuberculosis resistance in clinical isolates and sputum samples from re-treatment pulmonary tuberculosis patients.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is a major public health problem. Early diagnosis of MDR-TB patients is essential for minimizing the risk of Mycobacterium tuberculosis (MTB) transmission. The conventional drug susceptibility testing (DST) methods for detection of drug-resistant M. tuberculosis are laborious and cannot provide the rapid detection for clinical practice. METHODS: The aim of this study was to develop a pyrosequencing approach for the simultaneous detection of resistance to rifampin (RIF), isoniazid (INH), ethambutol (EMB), streptomycin (SM), ofloxacin (OFL) and amikacin (AMK) in M. tuberculosis clinical isolates and sputum samples from re-treatment pulmonary tuberculosis (PTB) patients. We identified the optimum conditions for detection mutation of rpoB, katG, rpsl, embB, gyrA and rrs gene by pyrosequencing. Then this approach was applied to detect 205 clinical isolates and 24 sputum samples of M. tuberculosis from re-treatment PTB patients. RESULTS: The mutations of rpoB and gyrA gene were detected by pyrosequencig with the SQA mode, and the mutations of katG, rpsl, embB, gyrA and rrs gene were detected by pyrosequencing with SNP mode. Compared with the Bactec MGIT 960 mycobacterial detection system, the accuracy of pyrosequencing for the detection of RIF, INH, EMB, SM, AMK and OFL resistance in clinical isolates was 95.0%, 79.2%, 70.3%, 84.5%, 96.5% and 91.1%, respectively. In sputum samples the accuracy was 83.3%, 83.3%, 60.9%, 83.3%, 87.5% and 91.7%, respectively. CONCLUSIONS: The newly established pyrosequencing assay is a rapid and high-throughput method for the detection of resistance to RIF, INH, SM, EMB, OFL and AMK in M. tuberculosis. Pyrosequencing can be used as a practical molecular diagnostic tool for screening and predicting the resistance of re-treatment pulmonary tuberculosis patients.

P-bRS: a physarum-based routing scheme for wireless sensor networks.

Routing in wireless sensor networks (WSNs) is an extremely challenging issue due to the features of WSNs. Inspired by the large and single-celled amoeboid organism, slime mold Physarum polycephalum, we establish a novel selecting next hop model (SNH). Based on this model, we present a novel Physarum-based routing scheme (P-bRS) for WSNs to balance routing efficiency and energy equilibrium. In P-bRS, a sensor node can choose the proper next hop by using SNH which comprehensively considers the distance, energy residue, and location of the next hop. The simulation results show how P-bRS can achieve the effective trade-off between routing efficiency and energy equilibrium compared to two famous algorithms.

Reputation revision method for selecting cloud services based on prior knowledge and a market mechanism.

The trust levels of cloud services should be evaluated to ensure their reliability. The effectiveness of these evaluations has major effects on user satisfaction, which is increasingly important. However, it is difficult to provide objective evaluations in open and dynamic environments because of the possibilities of malicious evaluations, individual preferences, and intentional praise. In this study, we propose a novel unfair rating filtering method for a reputation revision system. This method uses prior knowledge as the basis of similarity when calculating the average rating, which facilitates the recognition and filtering of unfair ratings. In addition, the overall performance is increased by a market mechanism that allows users and service providers to adjust their choice of services and service configuration in a timely manner. The experimental results showed that this method filtered unfair ratings in an effective manner, which greatly improved the precision of the reputation revision system.

Mycobacterium tuberculosis produces D-serine under hypoxia to limit CD8+ T cell-dependent immunity in mice.

Adaptation to hypoxia is a major challenge for the survival of Mycobacterium tuberculosis (Mtb) in vivo. Interferon (IFN)-γ-producing CD8+ T cells contribute to control of Mtb infection, in part by promoting antimicrobial activities of macrophages. Whether Mtb counters these responses, particularly during hypoxic conditions, remains unknown. Using metabolomic, proteomic and genetic approaches, here we show that Mtb induced Rv0884c (SerC), an Mtb phosphoserine aminotransferase, to produce D-serine. This activity increased Mtb pathogenesis in mice but did not directly affect intramacrophage Mtb survival. Instead, D-serine inhibited IFN-γ production by CD8+ T cells, which indirectly reduced the ability of macrophages to restrict Mtb upon co-culture. Mechanistically, D-serine interacted with WDR24 and inhibited mTORC1 activation in CD8+ T cells. This decreased T-bet expression and reduced IFN-γ production by CD8+ T cells. Our findings suggest an Mtb evasion mechanism where pathogen metabolic adaptation to hypoxia leads to amino acid-dependent suppression of adaptive anti-TB immunity.

Mycobacterium tuberculosis suppresses host antimicrobial peptides by dehydrogenating L-alanine.

Antimicrobial peptides (AMPs), ancient scavengers of bacteria, are very poorly induced in macrophages infected by Mycobacterium tuberculosis (M. tuberculosis), but the underlying mechanism remains unknown. Here, we report that L-alanine interacts with PRSS1 and unfreezes the inhibitory effect of PRSS1 on the activation of NF-κB pathway to induce the expression of AMPs, but mycobacterial alanine dehydrogenase (Ald) Rv2780 hydrolyzes L-alanine and reduces the level of L-alanine in macrophages, thereby suppressing the expression of AMPs to facilitate survival of mycobacteria. Mechanistically, PRSS1 associates with TAK1 and disruptes the formation of TAK1/TAB1 complex to inhibit TAK1-mediated activation of NF-κB pathway, but interaction of L-alanine with PRSS1, disables PRSS1-mediated impairment on TAK1/TAB1 complex formation, thereby triggering the activation of NF-κB pathway to induce expression of AMPs. Moreover, deletion of antimicrobial peptide gene ß-defensin 4 (Defb4) impairs the virulence by Rv2780 during infection in mice. Both L-alanine and the Rv2780 inhibitor, GWP-042, exhibits excellent inhibitory activity against M. tuberculosis infection in vivo. Our findings identify a previously unrecognized mechanism that M. tuberculosis uses its own alanine dehydrogenase to suppress host immunity, and provide insights relevant to the development of effective immunomodulators that target M. tuberculosis.

Mycobacterium tuberculosis inhibits METTL14-mediated m6A methylation of Nox2 mRNA and suppresses anti-TB immunity.

Internal N6-methyladenosine (m6A) modifications are among the most abundant modifications of messenger RNA, playing a critical role in diverse biological and pathological processes. However, the functional role and regulatory mechanism of m6A modifications in the immune response to Mycobacterium tuberculosis infection remains unknown. Here, we report that methyltransferase-like 14 (METTL14)-dependent m6A methylation of NAPDH oxidase 2 (Nox2) mRNA was crucial for the host immune defense against M. tuberculosis infection and that M. tuberculosis-secreted antigen EsxB (Rv3874) inhibited METTL14-dependent m6A methylation of Nox2 mRNA. Mechanistically, EsxB interacted with p38 MAP kinase and disrupted the association of TAB1 with p38, thus inhibiting the TAB1-mediated autophosphorylation of p38. Interaction of EsxB with p38 also impeded the binding of p38 with METTL14, thereby inhibiting the p38-mediated phosphorylation of METTL14 at Thr72. Inhibition of p38 by EsxB restrained liquid-liquid phase separation (LLPS) of METTL14 and its subsequent interaction with METTL3, preventing the m6A modification of Nox2 mRNA and its association with the m6A-binding protein IGF2BP1 to destabilize Nox2 mRNA, reduce ROS levels, and increase intracellular survival of M. tuberculosis. Moreover, deletion or mutation of the phosphorylation site on METTL14 impaired the inhibition of ROS level by EsxB and increased bacterial burden or histological damage in the lungs during infection in mice. These findings identify a previously unknown mechanism that M. tuberculosis employs to suppress host immunity, providing insights that may empower the development of effective immunomodulators that target M. tuberculosis.

Evaluation of methods for testing the susceptibility of clinical Mycobacterium tuberculosis isolates to pyrazinamide.

Pyrazinamide (PZA) is a first-line antituberculosis (anti-TB) drug capable of killing nonreplicating, persistent Mycobacterium tuberculosis. However, reliable testing of the susceptibility of M. tuberculosis to PZA is challenging. Using 432 clinical M. tuberculosis isolates, we compared the performances of five methods for the determination of M. tuberculosis susceptibility to PZA: the MGIT 960 system, the molecular drug susceptibility test (mDST), the pyrazinamidase (PZase) activity assay, the resazurin microtiter assay (REMA), and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction test. The sensitivities of the MGIT 960 system, the PZase activity assay, the mDST, the REMA, and the MTT assay were 98.8%, 88.8%, 90.5%, 98.8%, and 98.2%, respectively. The sensitivities of the PZase activity assay and the mDST were lower than those of the other three methods (P < 0.05). The specificities of the MGIT 960 system, the PZase activity assay, the mDST, the REMA and the MTT assays were 99.2%, 98.9%, 90.9%, 98.5%, and 100%, respectively. The specificity of the mDST was lower than those of the other four methods (P < 0.05). In conclusion, the MGIT 960 system, the MTT assay, and the REMA are superior to the PZase activity assay and the mDST in determining the susceptibility of M. tuberculosis to PZA. The MTT assay and the REMA might serve as alternative methods for clinical laboratories without access to the MGIT 960 system. For rapid testing in well-equipped laboratories, the mDST might be the best choice, particularly for small quantities of M. tuberculosis. The PZase activity assay has no obvious advantage in the assessment of M. tuberculosis susceptibility to PZA, as it is less accurate and requires larger quantities of bacteria.

Polymorphisms and gene expression of Notch4 in pulmonary tuberculosis.

Background: Tuberculosis (TB) is a serious public health problem to human health, but the pathogenesis of TB remains elusive. Methods: To identify novel candidate genes associated with TB susceptibility, we performed a population-based case control study to genotype 41SNPs spanning 21 genes in 435 pulmonary TB patients and 375 health donors from China. Results: We found Notch4 gene rs206018 and rs422951 polymorphisms were associated with susceptibility to pulmonary tuberculosis. The association was validated in another independent cohort including 790 TB patients and 1,190 healthy controls. Moreover, we identified that the rs206018 C allele was associated with higher level of Notch4 in PBMCs from pulmonary TB patients. Furthermore, Notch4 expression increased in TB patients and higher Notch4 expression correlated with the severer pulmonary TB. Finally, we explored the origin and signaling pathways involved in the regulation of Notch4 expression in response to Mycobacterium tuberculosis (Mtb) infection. We determine that Mtb induced Notch4 and its ligand Jagged1expression in macrophages, and Notch4 through TLR2/P38 signaling pathway and Jagged1 through TLR2/ERK signaling pathway. Conclusion: Our work further strengthens that Notch4 underlay an increased risk of TB in humans and is involved in the occurrence and development of TB, which could serve as a novel target for the host-targeted therapy of TB.