scholarly journals The tryptophan biosynthetic pathway is essential for Mycobacterium tuberculosis to cause disease

2020 ◽  
Vol 48 (5) ◽  
pp. 2029-2037
Author(s):  
J. Shaun Lott
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Biosynthetic Pathway ◽  
Infectious Agent ◽  
Tryptophan Biosynthesis ◽  
Bacterial Survival ◽  
Antibiotic Resistant ◽  
Resistant Disease ◽  
New Therapeutic Approaches ◽  
Long Duration ◽  
New Antibiotics

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is the most significant cause of death from a single infectious agent worldwide. Antibiotic-resistant strains of M. tuberculosis represent a threat to effective treatment, and the long duration, toxicity and complexity of current chemotherapy for antibiotic-resistant disease presents a need for new therapeutic approaches with novel modes of action. M. tuberculosis is an intracellular pathogen that must survive phagocytosis by macrophages, dendritic cells or neutrophils to establish an infection. The tryptophan biosynthetic pathway is required for bacterial survival in the phagosome, presenting a target for new classes of antitubercular compound. The enzymes responsible for the six catalytic steps that produce tryptophan from chorismate have all been characterised in M. tuberculosis, and inhibitors have been described for some of the steps. The innate immune system depletes cellular tryptophan in response to infection in order to inhibit microbial growth, and this effect is likely to be important for the efficacy of tryptophan biosynthesis inhibitors as new antibiotics. Allosteric inhibitors of both the first and final enzymes in the pathway have proven effective, including by a metabolite produced by the gut biota, raising the intriguing possibility that the modulation of tryptophan biosynthesis may be a natural inter-bacterial competition strategy.

scholarly journals A screen of covalent inhibitors in Mycobacterium tuberculosis identifies serine hydrolases involved in lipid metabolism as potential therapeutic targets

2021 ◽  
Author(s):  
Brett M. Babin ◽  
Laura J. Keller ◽  
Yishay Pinto ◽  
Veronica L Li ◽  
Andrew Eneim ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cell Envelope ◽  
Protein Profiling ◽  
Serine Hydrolases ◽  
Antibiotic Resistant ◽  
Competitive Activity ◽  
Covalent Inhibitors ◽  
New Antibiotics ◽  
Effective Therapeutic Strategy ◽  
Simultaneous Inhibition

The increasing incidence of antibiotic-resistant Mycobacterium tuberculosis infections is a global health threat necessitating the development of new antibiotics. Serine hydrolases (SHs) are a promising class of targets because of their importance for the synthesis of the mycobacterial cell envelope. We screened a library of small molecules containing serine-reactive electrophiles and identified narrow spectrum inhibitors of M. tuberculous growth. Using these lead molecules, we performed competitive activity-based protein profiling and identified multiple SH targets, including enzymes with uncharacterized functions. Lipidomic analyses of compound-treated cultures revealed an accumulation of free lipids and a substantial decrease in lipooligosaccharides, linking SH inhibition to defects in cell envelope biogenesis. Mutant analysis revealed a path to resistance via the synthesis of mycocerates, but not through mutations to target enzymes. Our results suggest that simultaneous inhibition of multiple SH enzymes is likely to be an effective therapeutic strategy for the treatment of M. tuberculosis infections.

The Biotin Biosynthetic Pathway in Mycobacterium tuberculosis is a Validated Target for the Development of Antibacterial Agents

2020 ◽  
Vol 27 (25) ◽  
pp. 4194-4232 ◽  
Author(s):  
Matthew R. Bockman ◽  
Neeraj Mishra ◽  
Courtney C. Aldrich
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Validation Studies ◽  
Biosynthetic Pathway ◽  
Antibacterial Agents ◽  
De Novo ◽  
Infectious Agent ◽  
Mammalian Host ◽  
Phenotypic Screening ◽  
Structure Based Drug Design ◽  
Solid Foundation

Mycobacterium tuberculosis, responsible for Tuberculosis (TB), remains the leading cause of mortality among infectious diseases worldwide from a single infectious agent, with an estimated 1.7 million deaths in 2016. Biotin is an essential cofactor in M. tuberculosis that is required for lipid biosynthesis and gluconeogenesis. M. tuberculosis relies on de novo biotin biosynthesis to obtain this vital cofactor since it cannot scavenge sufficient biotin from a mammalian host. The biotin biosynthetic pathway in M. tuberculosis has been well studied and rigorously genetically validated providing a solid foundation for medicinal chemistry efforts. This review examines the mechanism and structure of the enzymes involved in biotin biosynthesis and ligation, summarizes the reported genetic validation studies of the pathway, and then analyzes the most promising inhibitors and natural products obtained from structure-based drug design and phenotypic screening.

The Research of New Inhibitors of Bacterial Methionine Aminopeptidase by Structure Based Virtual Screening Approach of ZINC DATABASE and In Vitro Validation

2020 ◽  
Vol 16 (4) ◽  
pp. 389-401 ◽  
Author(s):  
Hanane Boucherit ◽  
Abdelouahab Chikhi ◽  
Abderrahmane Bensegueni ◽  
Amina Merzoug ◽  
Jean-Michel Bolla
Keyword(s):  
Virtual Screening ◽  
Bacterial Survival ◽  
Methionine Aminopeptidase ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Zinc Database ◽  
Promising Target ◽  
New Antibiotics ◽  
Potential Inhibitors

Background: The great emergence of multi-resistant bacterial strains and the low renewal of antibiotics molecules are leading human and veterinary medicine to certain therapeutic impasses. Therefore, there is an urgent need to find new therapeutic alternatives including new molecules in the current treatments of infectious diseases. Methionine aminopeptidase (MetAP) is a promising target for developing new antibiotics because it is essential for bacterial survival. Objective: To screen for potential MetAP inhibitors by in silico virtual screening of the ZINC database and evaluate the best potential lead molecules by in vitro studies. Methods: We have considered 200,000 compounds from the ZINC database for virtual screening with FlexX software to identify potential inhibitors against bacterial MetAP. Nine chemical compounds of the top hits predicted were purchased and evaluated in vitro. The antimicrobial activity of each inhibitor of MetAP was tested by the disc-diffusion assay against one Gram-positive (Staphylococcus aureus) and two Gram-negative (Escherichia coli & Pseudomonas aeruginosa) bacteria. Among the studied compounds, compounds ZINC04785369 and ZINC03307916 showed promising antibacterial activity. To further characterize their efficacy, the minimum inhibitory concentration was determined for each compound by the microdilution method which showed significant results. Results: These results suggest compounds ZINC04785369 and ZINC03307916 as promising molecules for developing MetAP inhibitors. Conclusion: Furthermore, they could therefore serve as lead molecules for further chemical modifications to obtain clinically useful antibacterial agents.

scholarly journals 833. Characteristics and Utilization Patterns of Colistin Compared with Newer Agents in Gram-Negative Infections

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S457-S457
Author(s):  
Stephen Marcella ◽  
Casey Doremus ◽  
Roger Echols
Keyword(s):  
Patient Characteristics ◽  
Total Hospital Cost ◽  
Healthcare Database ◽  
New Agents ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Days Of Therapy ◽  
New Antibiotics ◽  
The Usa ◽  
Utilization Patterns

Abstract Background Colistin has resurfaced in light of Gram-negative (GN) resistance. New antibiotics to treat antibiotic resistant GN infections (eg, ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam [new agents]), have recently been approved but their use vs colistin is unclear. We compared the overall use of colistin and new agents from 2014 to 2018 in patient days on therapy (PDOT). Methods Data on non-cystic fibrosis patients from the Premier Healthcare Database was used. PDOT was tabulated quarterly for Premier hospitals and projected to the US population. A subset of data from 2016 to 2018 with microbiologically confirmed GN (MCGN) infections was selected for adult inpatients receiving ≥3 days of therapy with colistin, new agents, carbapenems, or extended-spectrum cephalosporins. The index infection was defined either as the first carbapenem-resistant (CR) or -sensitive infection if no CR infection occurred. Patients could be treated with ≥1 antibiotic per infection. Utilization was examined by pathogen and patient characteristics. Results PDOT with colistin decreased from 2015 to 2018, while new agents have increased (Figure). During 2015–2018, colistin and any of 3 new agents were used by 3,320 and 5,781 inpatients, respectively, of whom, 649 (20%) and 1,284 (22%) had MCGN pathogens. Colistin-treated patients were sicker than patients treated with new agents (Table), underlying renal disease was present in 34.5% vs 36.3 %, and median length of stay of 17 vs 15 days, respectively. Mean total hospital cost was $93,815 vs $84,013 for colistin and new agents, respectively. Mortality was greater in colistin patients (18% vs 12%; p< 0.0001). CR infections constituted similar proportions of colistin and new agent use (79% vs 75%). Colistin accounted for 15.2% of CR Acinetobacter treatments and 9.7% of CR Enterobacterales (CRE) treatments compared with 4.5% and 12.8%, respectively, for new agents. Figure. Projected Inpatient PDOT Table. Conclusion Colistin use has decreased simultaneously with the introduction and increased use of new agents in the USA. Colistin was used more frequently in sicker patients and for Acinetobacter spp. infections than for CRE infections. Patients on colistin have worse outcomes, probably due to baseline differences in their health status. Disclosures Stephen Marcella, MD, Shionogi Inc. (Employee) Casey Doremus, MS, Shionogi Inc. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant)

scholarly journals Mycobacterium tuberculosis Infection Up-Regulates Sialyl Lewis X Expression in the Lung Epithelium

2021 ◽  
Vol 9 (1) ◽  
pp. 99
Author(s):  
Rita Matos ◽  
Kaori L. Fonseca ◽  
Stefan Mereiter ◽  
Ana Raquel Maceiras ◽  
Joana Gomes ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Biosynthetic Pathway ◽  
Molecular Mechanisms ◽  
Tuberculosis Infection ◽  
Host Susceptibility ◽  
Sialyl Lewis X ◽  
Lung Pathology ◽  
Lung Epithelium ◽  
Lewis X ◽  
Sialyl Lewis

Glycans display increasingly recognized roles in pathological contexts, however, their impact in the host-pathogen interplay in many infectious diseases remains largely unknown. This is the case for tuberculosis (TB), one of the ten most fatal diseases worldwide, caused by infection of the bacteria Mycobacterium tuberculosis. We have recently reported that perturbing the core-2 O-glycans biosynthetic pathway increases the host susceptibility to M. tuberculosis infection, by disrupting the neutrophil homeostasis and enhancing lung pathology. In the present study, we show an increased expression of the sialylated glycan structure Sialyl-Lewis X (SLeX) in the lung epithelium upon M. tuberculosis infection. This increase in SLeX glycan epitope is accompanied by an altered lung tissue transcriptomic signature, with up-regulation of genes codifying enzymes that are involved in the SLeX core-2 O-glycans biosynthetic pathway. This study provides novel insights into previously unappreciated molecular mechanisms involving glycosylation, which modulate the host response to M. tuberculosis infection, possibly contributing to shape TB disease outcome.

scholarly journals Antibiotic Pipeline Coordinators

2018 ◽  
Vol 46 (S1) ◽  
pp. 25-31 ◽  
Author(s):  
Enrico Baraldi ◽  
Olof Lindahl ◽  
Miloje Savic ◽  
David Findlay ◽  
Christine Årdal
Keyword(s):  
Research And Development ◽  
World Health ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Priority List ◽  
Non Profit ◽  
Global Priority ◽  
The World ◽  
New Antibiotics ◽  
Health Organization

The World Health Organization (WHO) has published a global priority list of antibiotic-resistant bacteria to guide research and development (R&D) of new antibiotics. Every pathogen on this list requires R&D activity, but some are more attractive for private sector investments, as evidenced by the current antibacterial pipeline. A “pipeline coordinator” is a governmental/non-profit organization that closely tracks the antibacterial pipeline and actively supports R&D across all priority pathogens employing new financing tools.

scholarly journals A novel site of insertion of IS6110 in the moaB3 gene of a clinical isolate of Mycobacterium tuberculosis

2011 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
Suma Sarojini ◽  
GK Madhavilatha ◽  
Smitha Soman ◽  
R Ajay Kumar ◽  
Sathish Mundayoor
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Isolate ◽  
Biosynthetic Pathway ◽  
Mobile Genetic Element ◽  
Point Mutations ◽  
Tuberculosis H37rv ◽  
Genomic Variation ◽  
Clinical Isolates ◽  
Pcr Analysis ◽  
Genome Plasticity

In Mycobacterium tuberculosis, genomic variation is generated mainly by insertions and deletions rather than by point mutations. RvD5 is one such deletion in M. tuberculosis H37Rv. Previous studies from our laboratory have shown the presence of moaA3 gene in the RvD5 region in a large number of clinical isolates, that is absent in M. tuberculosis H37Rv and H37Ra. The present study was aimed at investigating the RvD5 locus of the clinical isolates by a detailed PCR analysis. Here we report a new point of insertion of the mobile genetic element, IS6110 in the genome of one clinical isolate of M. tuberculosis. The insertion has disrupted the moaB3 gene, one of the ORFs in the RvD5 region, which is involved in the molybdopterin biosynthetic pathway. This insertion of IS6110 in the moaB3 of the clinical isolate is different when compared to the insertion in the moaB3 gene of M. tuberculosis H37Rv where 4kb RvD5 region has been lost by homologous recombination and only a truncated form of the gene is present. This finding is of relevance since IS6110 is a major element determining the genome plasticity of M. tuberculosis and its numerical and positional polymorphism has always been of special interest.

scholarly journals Mycobacterium tuberculosis Alters the Metalloprotease Activity of the COP9 Signalosome

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Lia Danelishvili ◽  
Lmar Babrak ◽  
Sasha J. Rose ◽  
Jamie Everman ◽  
Luiz E. Bermudez
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cop9 Signalosome ◽  
Virulence Determinants ◽  
Bacterial Survival ◽  
Phagocytic Cells ◽  
Content Type ◽  
Metalloprotease Activity ◽  
Macrophage Protein

ABSTRACT Inhibition of apoptotic death of macrophages by Mycobacterium tuberculosis represents an important mechanism of virulence that results in pathogen survival both in vitro and in vivo. To identify M. tuberculosis virulence determinants involved in the modulation of apoptosis, we previously screened a transposon bank of mutants in human macrophages, and an M. tuberculosis clone with a nonfunctional Rv3354 gene was identified as incompetent to suppress apoptosis. Here, we show that the Rv3354 gene encodes a protein kinase that is secreted within mononuclear phagocytic cells and is required for M. tuberculosis virulence. The Rv3354 effector targets the metalloprotease (JAMM) domain within subunit 5 of the COP9 signalosome (CSN5), resulting in suppression of apoptosis and in the destabilization of CSN function and regulatory cullin-RING ubiquitin E3 enzymatic activity. Our observation suggests that alteration of the metalloprotease activity of CSN by Rv3354 possibly prevents the ubiquitin-dependent proteolysis of M. tuberculosis-secreted proteins. IMPORTANCE Macrophage protein degradation is regulated by a protein complex called a signalosome. One of the signalosomes associated with activation of ubiquitin and protein labeling for degradation was found to interact with a secreted protein from M. tuberculosis, which binds to the complex and inactivates it. The interference with the ability to inactivate bacterial proteins secreted in the phagocyte cytosol may have crucial importance for bacterial survival within the phagocyte.

scholarly journals Bacterial defenses against a natural antibiotic promote collateral resilience to clinical antibiotics

2020 ◽  
Author(s):  
Lucas A. Meirelles ◽  
Elena K. Perry ◽  
Megan Bergkessel ◽  
Dianne K. Newman
Keyword(s):  
Antibiotic Resistance ◽  
Opportunistic Pathogen ◽  
Antimicrobial Treatment ◽  
Bacterial Survival ◽  
Human Pathogens ◽  
Opportunistic Pathogens ◽  
Chronic Infections ◽  
Antibiotic Resistant ◽  
Lung Infections ◽  
Environmental Microbes

SummaryAs antibiotic-resistant infections become increasingly prevalent worldwide, understanding the factors that lead to antimicrobial treatment failure is essential to optimizing the use of existing drugs. Opportunistic human pathogens in particular typically exhibit high levels of intrinsic antibiotic resistance and tolerance1, leading to chronic infections that can be nearly impossible to eradicate2. We asked whether the recalcitrance of these organisms to antibiotic treatment could be driven in part by their evolutionary history as environmental microbes, which frequently produce or encounter natural antibiotics3,4. Using the opportunistic pathogen Pseudomonas aeruginosa as a model, we demonstrate that the self-produced natural antibiotic pyocyanin (PYO) activates bacterial defenses that confer collateral tolerance to certain synthetic antibiotics, including in a clinically-relevant growth medium. Non-PYO-producing opportunistic pathogens isolated from lung infections similarly display increased antibiotic tolerance when they are co-cultured with PYO-producing P. aeruginosa. Furthermore, we show that beyond promoting bacterial survival in the presence of antibiotics, PYO can increase the apparent rate of mutation to antibiotic resistance by up to two orders of magnitude. Our work thus suggests that bacterial production of natural antibiotics in infections could play an important role in modulating not only the immediate efficacy of clinical antibiotics, but also the rate at which antibiotic resistance arises in multispecies bacterial communities.

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