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Mtb with host

Anjana Radhakrishnan, Christopher M Furze, Mohd Syed Ahangar, Elizabeth Fullam
One of the major obstacles to obtaining a complete structural and functional understanding of proteins encoded by the Mycobacterium tuberculosis ( Mtb ) pathogen is due to significant difficulties in producing recombinant mycobacterial proteins. Recent advances that have utilised the closely related Mycobacterium smegmatis species as a native host have been effective. Here we have developed a method for the rapid screening of both protein production and purification strategies of mycobacterial proteins in whole M...
September 27, 2018: RSC Advances
Katharina Ronacher, Roma Sinha, Michelle Cestari
Approximately 10% of individuals latently infected with Mycobacterium tuberculosis (Mtb) develop active tuberculosis (TB) during their lifetime. Although it is well recognized that T-helper 1 immune responses are crucial for containing latent TB infection, the full array of host factors conferring protective immunity from TB progression are not completely understood. IL-22 is produced by cells of the innate and adaptive immune system including innate lymphoid cells, and natural killer cells as well as T lymphocytes (Th1, Th17, and Th22) and binds to its cognate receptor, the IL-22R1, which is expressed on non-hematopoietic cells such as lung epithelial cells...
2018: Frontiers in Immunology
Emily S C Rittershaus, Seung-Hun Baek, Inna V Krieger, Samantha J Nelson, Yu-Shan Cheng, Subhalaxmi Nambi, Richard E Baker, John D Leszyk, Scott A Shaffer, James C Sacchettini, Christopher M Sassetti
Upon inhibition of respiration, which occurs in hypoxic or nitric oxide-containing host microenvironments, Mycobacterium tuberculosis (Mtb) adopts a non-replicating "quiescent" state and becomes relatively unresponsive to antibiotic treatment. We used comprehensive mutant fitness analysis to identify regulatory and metabolic pathways that are essential for the survival of quiescent Mtb. This genetic study identified a protein acetyltransferase (Mt-Pat/Rv0998) that promoted survival and altered the flux of carbon from oxidative to reductive tricarboxylic acid (TCA) reactions...
October 4, 2018: Cell Chemical Biology
Ruchi Paroha, Shivendra K Chaurasiya, Rashmi Chourasia
Mycobacterium tuberculosis (Mtb) infects millions of people each year. These bacilli can survive inside macrophages. To favor their survival, pathogen alters various signal transduction pathways in host cells. Phospholipase C (PLC) signaling regulates various processes in mammalian cells but has never been investigated for their roles in regulating phagocytosis and killing of mycobacteria by macrophages. Here, we report that infection with Mtb but not Mycobacterium smegmatis (MS) induces phosphorylation of PLC-γ2 at tyrosine 1217 in J774A...
October 14, 2018: Journal of Cellular Biochemistry
Anthony M Cadena, Yixuan Ma, Tao Ding, MacKenzie Bryant, Pauline Maiello, Adam Geber, Philana Ling Lin, JoAnne L Flynn, Elodie Ghedin
BACKGROUND: The specific interactions of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), and the lung microbiota in infection are entirely unexplored. Studies in cancer and other infectious diseases suggest that there are important exchanges occurring between host and microbiota that influence the immunological landscape. This can result in alterations in immune regulation and inflammation both locally and systemically. To assess whether Mtb infection modifies the lung microbiome, and identify changes in microbial abundance and diversity as a function of pulmonary inflammation, we compared infected and uninfected lung lobe washes collected serially from 26 macaques by bronchoalveolar lavage over the course of infection...
October 9, 2018: Microbiome
Thomas E Morrell, Ilona Urszula Rafalska-Metcalf, Haw Yang, Jhih-Wei Chu
Protein tyrosine phosphatase B (PtpB) from Mycobacterium tuberculosis (Mtb) extends the bacteria's survival in hosts and hence is a potential target for Mtb-specific drugs. To study how Mtb-specific sequence insertions in PtpB may regulate access to its active site through large-amplitude conformational changes, we performed free-energy calculations using an all-atom explicit solvent model. Corroborated by biochemical assays, the results show that PtpB's active site is controlled via an "either/or" compound conformational gating mechanism---an unexpected discovery that Mtb has evolved to bestow a single enzyme with such intricate logical operations...
October 10, 2018: Journal of the American Chemical Society
Nguyen T T Thuong, Dao N Vinh, Hoang T Hai, Do D A Thu, Le T H Nhat, Dorothee Heemskerk, Nguyen D Bang, Maxine Caws, Nguyen T H Mai, Guy E Thwaites
Background: Mycobacterium tuberculosis (Mtb) bacillary load in the brain of those with tuberculous meningitis (TBM) may reflect the host ability to control the pathogen and determine disease severity and treatment outcomes. Methods: We measured pre-treatment cerebrospinal fluid (CSF) Mtb bacterial load by GeneXpert in 692 adults with TBM. We sought to understand the relationship between CSF bacterial load and inflammation, and their respective impact on disease severity and treatment outcomes...
October 9, 2018: Journal of Infectious Diseases
Seon-Hwa Kim, Soo-Na Cho, Yun-Ji Lim, Ji-Ae Choi, Junghwan Lee, Dam Go, Chang-Hwa Song
Background: Mycobacterium smegmatis , a rapidly growing non-tuberculosis mycobacterium, is a good model for studying the pathogenesis of tuberculosis because of its genetic similarity to Mycobacterium tuberculosis (Mtb). Macrophages remove mycobacteria during an infection. Macrophage apoptosis is a host defense mechanism against intracellular bacteria. We have reported that endoplasmic reticulum (ER) stress is an important host defense mechanism against Mtb infection. Results: In this study, we found that M...
2018: Cell & Bioscience
Fan-Lin Wu, Yin Liu, Hai-Nan Zhang, He-Wei Jiang, Li Cheng, Shu-Juan Guo, Jiao-Yu Deng, Li-Jun Bi, Xian-En Zhang, Hua-Fang Gao, Sheng-Ce Tao
Mycobacterium tuberculosis (Mtb) serine/threonine kinase PknG plays an important role in the Mtb-host interaction by facilitating the survival of Mtb in macrophages. However, the human proteins with which the PknG interacts, and the underlying molecular mechanisms are still largely unknown. In this study, we applied a HuProtTM array to globally identify the host proteins to which PknG binds. In this way, we discovered 125 interactors, including a cyclophilin protein, CypA. This interaction between PknG and CypA was validated both in vitro and in vivo, and functional studies showed that PknG significantly reduces the protein levels of CypA through phosphorylation, which consequently inhibit the inflammatory response through down-regulation of NF-κB and ERK1/2 pathways...
October 3, 2018: Proteomics
Woo Sik Kim, Jong-Seok Kim, Hong Min Kim, Kee Woong Kwon, Seok-Yong Eum, Sung Jae Shin
Antigens (Ags) in Mycobacterium tuberculosis (Mtb) that are constitutively expressed, overexpressed during growth, essential for survival, and highly conserved may be good vaccine targets if they induce the appropriate anti-Mtb Th1 immune response. In this context, stress response-related antigens of Mtb might serve as attractive targets for vaccine development as they are rapidly expressed and are up-regulated during Mtb infection in vivo. Our group recently demonstrated that GrpE, encoded by rv0351 as a cofactor of heat-shock protein 70 (HSP70) in the DnaK operon, is a novel immune activator that interacts with DCs to generate Th1-biased memory T cells in an antigen-specific manner...
September 26, 2018: Scientific Reports
Hongjun Yu, Tania J Lupoli, Amanda Kovach, Xing Meng, Gongpu Zhao, Carl F Nathan, Huilin Li
The protein disaggregase ClpB hexamer is conserved across evolution and has two AAA+-type nucleotide-binding domains, NBD1 and NBD2, in each protomer. In M. tuberculosis ( Mtb ), ClpB facilitates asymmetric distribution of protein aggregates during cell division to help the pathogen survive and persist within the host, but a mechanistic understanding has been lacking. Here we report cryo-EM structures at 3.8- to 3.9-Å resolution of Mtb ClpB bound to a model substrate, casein, in the presence of the weakly hydrolyzable ATP mimic adenosine 5'-[γ-thio]triphosphate...
October 9, 2018: Proceedings of the National Academy of Sciences of the United States of America
Priya Kalra, Subodh Kumar Mishra, Surinder Kaur, Amit Kumar, Hanumanthappa Krishna Prasad, Tarun Kumar Sharma, Jaya Sivaswami Tyagi
The entry and survival of Mycobacterium tuberculosis (Mtb) within host cells is orchestrated partly by an essential histone-like protein HupB (Rv2986c). Despite being an essential drug target, the lack of structural information has impeded the development of inhibitors targeting the indispensable and multifunctional C-terminal domain (CTD) of HupB. To bypass the requirement for structural information in the classical drug discovery route, we generated a panel of DNA aptamers against HupB protein through systemic evolution of ligands by exponential (SELEX) enrichment...
August 22, 2018: Molecular Therapy. Nucleic Acids
Stephanie Wehrstedt, Jan Kubis, Andreas Zimmermann, Heiko Bruns, Daniel Mayer, Mark Grieshober, Steffen Stenger
Tyrosine kinases are checkpoints for multiple cellular pathways and dysregulation induces malignancies, most notably chronic myeloid leukemia (CML). Inhibition of Abl-tyrosine kinases has evolved as a new concept for the treatment of CML and other malignant diseases. Due to the multiple immune-modulatory pathways controlled by tyrosine kinases, treatment with tyrosine kinase inhibitors (TKIs) will not only affect the biology of malignant cells but also modulate physiological immune functions. To understand the effects of TKIs on host defense against intracellular bacteria, we investigated the immunological impact of the dual Abl/Src TKI dasatinib on the cellular immune response to Mycobacterium tuberculosis (Mtb)...
September 22, 2018: European Journal of Immunology
Heidi J Zapata, Peter H Van Ness, Stefan Avey, Barbara Siconolfi, Heather G Allore, Sui Tsang, Jean Wilson, Lydia Barakat, Subhasis Mohanty, Albert C Shaw
Both aging and HIV infection are associated with an enhanced pro-inflammatory environment that contributes to impaired immune responses and is mediated in part by innate immune pattern-recognition receptors. MINCLE is a C-type lectin receptor that recognizes trehalose 6,6,' di-mycolate (TDM) or "cord factor," the most abundant glycolipid in Mycobacterium tuberculosis (MTB). Here, we evaluated MINCLE function in monocytes in a cohort of HIV-infected and uninfected young (21-35) and older adults (60 years) via stimulation of PBMCs with TDB (Trehalose-6,6-dibehenate), a synthetic analog of TDM and measurement of cytokine production (IL-10, IL-12, IL-6, TNF-) by multicolor flow cytometry...
September 15, 2018: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
Nicole C Howard, Nancy D Marin, Mushtaq Ahmed, Bruce A Rosa, John Martin, Monika Bambouskova, Alexey Sergushichev, Ekaterina Loginicheva, Natalia Kurepina, Javier Rangel-Moreno, Liang Chen, Barry N Kreiswirth, Robyn S Klein, Joan-Miquel Balada-Llasat, Jordi B Torrelles, Gaya K Amarasinghe, Makedonka Mitreva, Maxim N Artyomov, Fong-Fu Hsu, Barun Mathema, Shabaana A Khader
Tuberculosis is a significant global health threat, with one-third of the world's population infected with its causative agent Mycobacterium tuberculosis (Mtb). The emergence of multidrug-resistant (MDR) Mtb that is resistant to the frontline anti-tubercular drugs rifampicin and isoniazid forces treatment with toxic second-line drugs. Currently, ~4% of new and ~21% of previously treated tuberculosis cases are either rifampicin-drug-resistant or MDR Mtb infections1 . The specific molecular host-pathogen interactions mediating the rapid worldwide spread of MDR Mtb strains remain poorly understood...
October 2018: Nature Microbiology
Rym Ouni, Houda Gharsalli, Violette Dirix, Amani Braiek, Nadia Sendi, Afifa Jarraya, Leila Douik El Gharbi, Mohamed-Ridha Barbouche, Chaouki Benabdessalem
Nearly two billion people are latently infected with Mtb (LTBI). Detection of LTBI with high risk to develop active tuberculosis (aTB) is considered the cornerstone to control the disease. The current challenge is to identify markers that better classify LTBI versus aTB. It has been previously shown that Rv0140, a reactivation-associated antigen of Mtb, induces significantly higher IFN-γ production in LTBI individuals as compared to aTB patients. Herein, we show that Rv0140 induces high granzyme B level by PBMCs derived from LTBI (n = 34) as compared to aTB (n = 18)...
September 13, 2018: Journal of Leukocyte Biology
Flavio De Maio, Basem Battah, Valentina Palmieri, Linda Petrone, Francesco Corrente, Alessandro Salustri, Ivana Palucci, Silvia Bellesi, Massimiliano Papi, Salvatore Rubino, Michela Sali, Delia Goletti, Maurizio Sanguinetti, Riccardo Manganelli, Marco De Spirito, Giovanni Delogu
PE_PGRSs of Mycobacterium tuberculosis (Mtb) represent a family of complex and peculiar proteins whose role and function remain elusive. In this study, we investigated PE_PGRS3 and PE_PGRS4, two highly homologous PE_PGRSs encoded by two contiguous genes in the Mtb genome. Using a gene-reporter system in Mycobacterium smegmatis (Ms) and transcriptional analysis in Mtb, we show that PE_PGRS3, but not PE_PGRS4, is specifically expressed under low phosphate concentrations. Interestingly, PE_PGRS3, but not PE_PGRS4, has a unique, arginine-rich C-terminal domain of unknown function...
September 7, 2018: Cellular Microbiology
Tingting Yang, Jun Zhong, Ju Zhang, Cuidan Li, Xia Yu, Jingfa Xiao, Xinmiao Jia, Nan Ding, Guannan Ma, Guirong Wang, Liya Yue, Qian Liang, Yongjie Sheng, Yanhong Sun, Hairong Huang, Fei Chen
Tuberculosis (TB) has surpassed HIV as the leading infectious disease killer worldwide since 2014. The main pathogen, Mycobacterium tuberculosis (Mtb), contains ~4,000 genes that account for ~90% of the genome. However, it is still unclear which of these genes are primary/secondary, which are responsible for generality/individuality, and which interconvert during evolution. Here we utilized a pan-genomic analysis of 36 Mtb genomes to address these questions. We identified 3,679 Mtb core (i.e., primary) genes, determining their phenotypic generality (e...
2018: Frontiers in Microbiology
Yang Lu, Xin-Min Wang, Pu Yang, Ling Han, Ying-Zi Wang, Zhi-Hong Zheng, Fang Wu, Wan-Jiang Zhang, Le Zhang
BACKGROUND: Apoptosis and inflammation have been shown to play an important role in the mechanisms involved in the pathogenesis of Mycobacterium tuberculosis (MTB) infection. When macrophages undergo apoptosis and polarization, gap junctions (GJs) may be needed to provide conditions for their functions. Connexin 43 (Cx43) and connexin 37 (Cx37) are the main connexins in macrophages that participate in the formation of GJ channels. METHODS: An H37Rv infection RAW264...
August 2018: Medicine (Baltimore)
Sara B Cohen, Benjamin H Gern, Jared L Delahaye, Kristin N Adams, Courtney R Plumlee, Jessica K Winkler, David R Sherman, Michael Y Gerner, Kevin B Urdahl
Mycobacterium tuberculosis (Mtb) infection is initiated in the distal airways, but the bacteria ultimately disseminate to the lung interstitium. Although various cell types, including alveolar macrophages (AM), neutrophils, and permissive monocytes, are known to be infected with Mtb, the initially infected cells as well as those that mediate dissemination from the alveoli to the lung interstitium are unknown. In this study, using a murine infection model, we reveal that early, productive Mtb infection occurs almost exclusively within airway-resident AM...
September 12, 2018: Cell Host & Microbe
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