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iron metabolism in tb

Jude T Chenge, Le Van Duyet, Shalini Swami, Kirsty J McLean, Madeline E Kavanagh, Anthony G Coyne, Stephen E J Rigby, Myles R Cheesman, Hazel M Girvan, Colin W Levy, Bernd Rupp, Jens P von Kries, Chris Abell, David Leys, Andrew W Munro
The Mycobacterium tuberculosis H37Rv genome encodes 20 cytochromes P450, including P450s crucial to infection and bacterial viability. Many M. tuberculosis P450s remain uncharacterized, suggesting that their further analysis may provide new insights into M. tuberculosis metabolic processes and new targets for drug discovery. CYP126A1 is representative of a P450 family widely distributed in mycobacteria and other bacteria. Here we explore the biochemical and structural properties of CYP126A1, including its interactions with new chemical ligands...
January 27, 2017: Journal of Biological Chemistry
Kirsty J McLean, Andrew W Munro
TB, caused by the human pathogen Mycobacterium tuberculosis (Mtb), causes more deaths than any other infectious disease. Iron is crucial for Mtb to infect the host and to sustain infection, with Mtb encoding large numbers of iron-binding proteins. Many of these are hemoproteins with key roles, including defense against oxidative stress, cellular signaling and regulation, host cholesterol metabolism, and respiratory processes. Various heme enzymes in Mtb are validated drug targets and/or products of genes essential for bacterial viability or survival in the host...
November 14, 2016: Drug Discovery Today
Takemasa Takii
Mycobacterium species are exposed to oxidative and nitrosylative stress from environments within and outside the host cells. After the host is infected with the bacilli, macrophages produce superoxide molecules via NADPH oxidase activity and nitric oxide (NO) via inducible NO synthase activity to kill the bacilli. The pathogenic bacilli can successfully survive in host cells via anti-oxidative and anti-nitrosylative mechanisms. In particular, Mycobacterium tuberculosis persisters pose a great problem for chemotherapy because most anti-mycobacterial drugs are ineffective against mycobacteria that are in the persistent state...
July 2015: Kekkaku: [Tuberculosis]
Selvakumar Subbian, Ruchi Pandey, Patricia Soteropoulos, G Marcela Rodriguez
Mycobacterium tuberculosis the causative agent of tuberculosis affects millions of people worldwide. New tools for treatment and prevention of tuberculosis are urgently needed. We previously showed that a ferritin (bfrB) mutant of M. tuberculosis has altered iron homeostasis and increased sensitivity to antibiotics and to microbicidal effectors produced by activated macrophages. Most importantly, M. tuberculosis lacking BfrB is strongly attenuated in mice, especially, during the chronic phase of infection. In this study, we examined whether immunization with a bfrB mutant could confer protection against subsequent infection with virulent M...
2015: Journal of Immunology Research
Krishna Kurthkoti, Priyanka Tare, Rakhi Paitchowdhury, Vykuntham Naga Gowthami, Maria J Garcia, Roberto Colangeli, Dipankar Chatterji, Valakunja Nagaraja, G Marcela Rodriguez
Emerging evidence indicates that precise regulation of iron (Fe) metabolism and maintenance of Fe homeostasis in Mycobacterium tuberculosis (Mtb) are essential for its survival and proliferation in the host. IdeR is a central transcriptional regulator of Mtb genes involved in Fe metabolism. While it is well understood how IdeR functions as a repressor, how it induces transcription of a subset of its targets is still unclear. We investigated the molecular mechanism of IdeR-mediated positive regulation of bfrB, the gene encoding the major Fe-storage protein of Mtb...
December 2015: Molecular Microbiology
Abhishek Mishra, Dhiman Sarkar
Vitamin C is a critical dietary nutrient in human which has a wide range of regulatory effects on gene expression and physiology of Mycobacterium tuberculosis that leads to a dormant drug-tolerant phenotype. In the presence of iron, vitamin C shows a high bactericidal activity even in the drug resistant phenotype of M. tuberculosis. The regulatory mechanisms underlying vitamin C induced adaptations are largely unknown due to lack of functional genomics data in this field. In this study, we attempt to characterize the direct effect of vitamin C treatment on the physiology of actively growing Mycobacterium smegmatis...
2015: Frontiers in Microbiology
Yusuke Minato, Joshua M Thiede, Shannon Lynn Kordus, Edward J McKlveen, Breanna J Turman, Anthony D Baughn
para-Aminosalicylic acid (PAS) entered clinical use in 1946 as the second exclusive drug for the treatment of tuberculosis (TB). While PAS was initially a first-line TB drug, the introduction of more potent antitubercular agents relegated PAS to the second-line tier of agents used for the treatment of drug-resistant Mycobacterium tuberculosis infections. Despite the long history of PAS usage, an understanding of the molecular and biochemical mechanisms governing the susceptibility and resistance of M. tuberculosis to this drug has lagged behind that of most other TB drugs...
September 2015: Antimicrobial Agents and Chemotherapy
Rienk A Rienksma, Maria Suarez-Diez, Hans-Joachim Mollenkopf, Gregory M Dolganov, Anca Dorhoi, Gary K Schoolnik, Vitor Ap Martins Dos Santos, Stefan He Kaufmann, Peter J Schaap, Martin Gengenbacher
BACKGROUND: The human pathogen Mycobacterium tuberculosis has the capacity to escape eradication by professional phagocytes. During infection, M. tuberculosis resists the harsh environment of phagosomes and actively manipulates macrophages and dendritic cells to ensure prolonged intracellular survival. In contrast to other intracellular pathogens, it has remained difficult to capture the transcriptome of mycobacteria during infection due to an unfavorable host-to-pathogen ratio. RESULTS: We infected the human macrophage-like cell line THP-1 with the attenuated M...
February 5, 2015: BMC Genomics
Khisimuzi Mdluli, Takushi Kaneko, Anna Upton
The recent accelerated approval for use in extensively drug-resistant and multidrug-resistant-tuberculosis (MDR-TB) of two first-in-class TB drugs, bedaquiline and delamanid, has reinvigorated the TB drug discovery and development field. However, although several promising clinical development programs are ongoing to evaluate new TB drugs and regimens, the number of novel series represented is few. The global early-development pipeline is also woefully thin. To have a chance of achieving the goal of better, shorter, safer TB drug regimens with utility against drug-sensitive and drug-resistant disease, a robust and diverse global TB drug discovery pipeline is key, including innovative approaches that make use of recently acquired knowledge on the biology of TB...
June 2015: Cold Spring Harbor Perspectives in Medicine
Jeffrey Green, Matthew D Rolfe, Laura J Smith
Molecular oxygen (O2) and nitric oxide (NO) are diatomic gases that play major roles in infection. The host innate immune system generates reactive oxygen species and NO as bacteriocidal agents and both require O2 for their production. Furthermore, the ability to adapt to changes in O2 availability is crucial for many bacterial pathogens, as many niches within a host are hypoxic. Pathogenic bacteria have evolved transcriptional regulatory systems that perceive these gases and respond by reprogramming gene expression...
2014: Virulence
Kip P Conner, Alex A Cruce, Matthew D Krzyaniak, Alina M Schimpf, Daniel J Frank, Paul Ortiz de Montellano, William M Atkins, Michael K Bowman
Azoles and pyridines are commonly incorporated into small molecule inhibitor scaffolds that target cytochromes P450 (CYPs) as a strategy to increase drug binding affinity, impart isoform-dependent selectivity, and improve metabolic stability. Optical absorbance spectra of the CYP-inhibitor complex are widely used to infer whether these inhibitors are ligated directly to the heme iron as catalytically inert, low-spin (type II) complexes. Here, we show that the low-spin complex between a drug-metabolizing CYP2C9 variant and 4-(3-phenylpropyl)-1H-1,2,3-triazole (PPT) retains an axial water ligand despite exhibiting elements of "classic" type II optical behavior...
February 10, 2015: Biochemistry
Mingyan Sun, Zhengjun Yi, Yurong Fu
No abstract text is available yet for this article.
October 2014: Chinese Journal of Tuberculosis and Respiratory Diseases
Surajit Chakraborty, Rajasri Bhattacharyya, Kirtimaan Sayal, Dibyajyoti Banerjee
The scenario of tuberculosis has gone deadly due to its high prevalence and emergence of widespread drug resistance. It is now high time to develop novel antimycobacterial strategies and to understand novel mechanisms of existing antimycobacterial compounds so that we are equipped with newer tuberculosis controlling molecules in the days to come. Iron has proven to be essential for pathogenesis of tuberculosis and retinoic acid is known to influence the iron metabolism pathway. Retenoic acid is also known to exhibit antitubercular effect in in vivo system...
2014: Current Pharmaceutical Biotechnology
Mina Javaheri-Kermani, Touraj Farazmandfar, Abolghasem Ajami, Yaghoub Yazdani
BACKGROUND: Iron acquisition is essential for the growth of Mycobacterium tuberculosis. Hepcidin is known as an antimicrobial peptide and a component of the innate immune response. Hepcidin inhibits M. tuberculosis growth in vitro. In this study, we decided to identify -582A> G variants of the HAMP promoter in patients with tuberculosis (TB) and investigate its effect on serum iron, ferritin, and hepcidin levels. METHODS: The sample population consisted of 105 patients with TB and 104 healthy individuals...
October 2014: Scandinavian Journal of Infectious Diseases
John D MacMicking
Few pathogens run the gauntlet of sterilizing immunity like Mycobacterium tuberculosis (Mtb). This organism infects mononuclear phagocytes and is also ingested by neutrophils, both of which possess an arsenal of cell-intrinsic effector mechanisms capable of eliminating it. Here Mtb encounters acid, oxidants, nitrosylating agents, and redox congeners, often exuberantly delivered under low oxygen tension. Further pressure is applied by withholding divalent Fe²⁺, Mn²⁺, Cu²⁺, and Zn²⁺, as well as by metabolic privation in the form of carbon needed for anaplerosis and aromatic amino acids for growth...
October 2014: Cold Spring Harbor Perspectives in Medicine
Carlo Bonchi, Francesco Imperi, Fabrizia Minandri, Paolo Visca, Emanuela Frangipani
While the occurrence and spread of antibiotic resistance in bacterial pathogens is vanishing current anti-infective therapies, the antibiotic discovery pipeline is drying up. In the last years, the repurposing of existing drugs for new clinical applications has become a major research area in drug discovery, also in the field of anti-infectives. This review discusses the potential of repurposing previously approved gallium formulations in antibacterial chemotherapy. Gallium has no proven function in biological systems, but it can act as an iron-mimetic in both prokaryotic and eukaryotic cells...
May 2014: BioFactors
Christopher M Jones, Ryan M Wells, Ashoka V R Madduri, Matthew B Renfrow, Colin Ratledge, D Branch Moody, Michael Niederweis
Siderophores are small iron-binding molecules secreted by bacteria to scavenge iron. Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis, produces the siderophores mycobactin and carboxymycobactin. Complexes of the mycobacterial membrane proteins MmpS4 and MmpS5 with the transporters MmpL4 and MmpL5 are required for siderophore export and virulence in Mtb. Here we show that, surprisingly, mycobactin or carboxymycobactin did not rescue the low-iron growth defect of the export mutant but severely impaired growth...
February 4, 2014: Proceedings of the National Academy of Sciences of the United States of America
Jeffrey Green, Matthew D Rolfe, Laura J Smith
Molecular oxygen (O 2) and nitric oxide (NO) are diatomic gases that play major roles in infection. The host innate immune system generates reactive oxygen species and NO as bacteriocidal agents and both require O 2 for their production. Furthermore, the ability to adapt to changes in O 2 availability is crucial for many bacterial pathogens, as many niches within a host are hypoxic. Pathogenic bacteria have evolved transcriptional regulatory systems that perceive these gases and respond by reprogramming gene expression...
February 4, 2014: Virulence
Rudi Wisaksana, Quirijn de Mast, Bachti Alisjahbana, Hadi Jusuf, Primal Sudjana, Agnes R Indrati, Rachmat Sumantri, Dorine Swinkels, Reinout van Crevel, Andre van der Ven
BACKGROUND: Distortion of iron homeostasis may contribute to the pathogenesis of human immunodeficiency virus (HIV) infection and tuberculosis (TB). We studied the association of the central iron-regulatory hormone hepcidin with the severity of HIV and the association between hepcidin and other markers of iron homeostasis with development of TB. METHODS: Three groups of patients were selected from a prospective cohort of HIV-infected subjects in Bandung, Indonesia...
2013: PloS One
Agnese Serafini, Davide Pisu, Giorgio Palù, G Marcela Rodriguez, Riccardo Manganelli
ESX-3 is one of the five type VII secretion systems encoded by the Mycobacterium tuberculosis genome. We recently showed the essentiality of ESX-3 for M. tuberculosis viability and proposed its involvement in iron and zinc metabolism. In this study we confirmed the role of ESX-3 in iron uptake and its involvement in the adaptation to low zinc environment in M. tuberculosis. Moreover, we unveiled functional differences between the ESX-3 roles in M. tuberculosis and M. smegmatis showing that in the latter ESX-3 is only involved in the adaptation to iron and not to zinc restriction...
2013: PloS One
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