Quantitative Protein Profiling of Chlamydia trachomatis Growth Forms Reveals Defense Strategies Against Tryptophan Starvation

Østergaard, Ole; Follmann, Frank; Olsen, Anja; Heegaard, Niels H. H.; Andersen, Peter; Rosenkrands, Ida

doi:10.1074/mcp.m116.061986

Cited by 26 publications

(50 citation statements)

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“…Broadly speaking, these effects are likely mediated by the inability to efficiently translate key proteins enriched in Trp residues (Fig. 1) (18,33,34). More recent studies have characterized transcriptional and translational changes associated with IFN-␥-mediated persistence (18,30).…”

Section: Discussionmentioning

confidence: 99%

Inhibition of tRNA Synthetases Induces Persistence inChlamydia

Hatch

Ouellette

2020

Infect Immun

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Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections, and Chlamydia pneumoniae causes community-acquired respiratory infections. In vivo, the host immune system will release gamma interferon (IFN-γ) to combat infection. IFN-γ activates human cells to produce the tryptophan (Trp)-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO). Consequently, there is a reduction in cytosolic Trp in IFN-γ-activated host cells. In evolving to obligate intracellular dependence, Chlamydia has significantly reduced its genome size and content, as it relies on the host cell for various nutrients. Importantly, C. trachomatis and C. pneumoniae are Trp auxotrophs and are starved for this essential nutrient when the human host cell is exposed to IFN-γ. To survive this, chlamydiae enter an alternative developmental state referred to as persistence. Chlamydial persistence is characterized by a halt in the division cycle, aberrant morphology, and, in the case of IFN-γ-induced persistence, Trp codon-dependent changes in transcription. We hypothesize that these changes in transcription are dependent on the particular amino acid starvation state. To investigate the chlamydial response mechanisms acting when other amino acids become limiting, we tested the efficacy of prokaryote-specific tRNA synthetase inhibitors, indolmycin and AN3365, to mimic starvation of Trp and leucine, respectively. We show that these drugs block chlamydial growth and induce changes in morphology and transcription consistent with persistence. Importantly, growth inhibition was reversed when the compounds were removed from the medium. With these data, we find that indolmycin and AN3365 are valid tools that can be used to mimic the persistent state independently of IFN-γ.

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Section: Discussionmentioning

confidence: 99%

Inhibition of tRNA Synthetases Induces Persistence inChlamydia

Hatch

Ouellette

2020

Infect Immun

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“…For intracellular pathogens that have to compete for nutrients within the host cells, metabolism is a keystone to the outcome of infection. Several recent studies show that amino acids are central to the host-pathogen metabolic interaction (Belland et al, 2003 ; Baruch et al, 2014 ; Olive and Sassetti, 2016 ; Østergaard et al, 2016 ). For example, group A Streptococcus (GAS) uses asparagine for sensing the host immune status (Baruch et al, 2014 ).…”

Section: Discussionmentioning

confidence: 99%

Ixodes scapularis Tick Cells Control Anaplasma phagocytophilum Infection by Increasing the Synthesis of Phosphoenolpyruvate from Tyrosine

Cabezas-Cruz

Espinosa

Obregón

et al. 2017

Front. Cell. Infect. Microbiol.

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The obligate intracellular pathogen, Anaplasma phagocytophilum, is the causative agent of life-threatening diseases in humans and animals. A. phagocytophilum is an emerging tick-borne pathogen in the United States, Europe, Africa and Asia, with increasing numbers of infected people and animals every year. It is increasingly recognized that intracellular pathogens modify host cell metabolic pathways to increase infection and transmission in both vertebrate and invertebrate hosts. Recent reports have shown that amino acids are central to the host–pathogen metabolic interaction. In this study, a genome-wide search for components of amino acid metabolic pathways was performed in Ixodes scapularis, the main tick vector of A. phagocytophilum in the United States, for which the genome was recently published. The enzymes involved in the synthesis and degradation pathways of the twenty amino acids were identified. Then, the available transcriptomics and proteomics data was used to characterize the mRNA and protein levels of I. scapularis amino acid metabolic pathway components in response to A. phagocytophilum infection of tick tissues and ISE6 tick cells. Our analysis was focused on the interplay between carbohydrate and amino acid metabolism during A. phagocytophilum infection in ISE6 cells. The results showed that tick cells increase the synthesis of phosphoenolpyruvate (PEP) from tyrosine to control A. phagocytophilum infection. Metabolic pathway analysis suggested that this is achieved by (i) increasing the transcript and protein levels of mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M), (ii) shunting tyrosine into the tricarboxylic acid (TCA) cycle to increase fumarate and oxaloacetate which will be converted into PEP by PEPCK-M, and (iii) blocking all the pathways that use PEP downstream gluconeogenesis (i.e., de novo serine synthesis pathway (SSP), glyceroneogenesis and gluconeogenesis). While sequestering host PEP may be critical for this bacterium because it cannot actively carry out glycolysis to produce PEP, excess of this metabolite may be toxic for A. phagocytophilum. The present work provides a more comprehensive view of the major amino acid metabolic pathways involved in the response to pathogen infection in ticks, and provides the basis for further studies to develop novel strategies for the control of granulocytic anaplasmosis.

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“…These effects were connected with the ability of human IFNγ to induce a tryptophan-limiting environment in the cell by activating IDO expression (12). Broadly speaking, these effects are likely mediated by the inability to efficiently translate key proteins enriched in trp residues (see Fig.1 and (18, 33, 34)). More recent studies have characterized transcriptional and translational changes associated with IFNγ-mediated persistence (18, 30).…”

Section: Discussionmentioning

confidence: 99%

Inhibition of tRNA Synthetases Induces Persistence inChlamydia

Hatch

Ouellette

2019

Preprint

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18Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections, and C. 19 pneumoniae causes community-acquired respiratory infections. In vivo, the host immune system 20 will release interferon-gamma (IFNγ) to combat infection. IFNγ activates human cells to produce 21 the tryptophan (trp) catabolizing enzyme, IDO. Consequently, there is a reduction in cytosolic trp 22 in IFNγ-activated host cells. In evolving to obligate intracellular dependence, Chlamydia has 23 significantly reduced its genome size and content as it relies on the host cell for various nutrients. 24 Importantly, C. trachomatis and C. pneumoniae are trp auxotrophs and are starved for this essential 25 nutrient when the human host cell is exposed to IFNγ. To survive this, chlamydiae enter an 26 alternative growth state referred to as persistence. Chlamydial persistence is characterized by a 27 halt in the division cycle, aberrant morphology, and, in the case of IFNγ-induced persistence, trp 28 codon-dependent changes in transcription. We hypothesize that these changes in transcription are 29 dependent on the particular amino acid starvation state. To investigate the chlamydial response 30 mechanisms acting when other amino acids become limiting, we tested the efficacy of prokaryotic 31 specific tRNA synthetase inhibitors, indolmycin and AN3365, to mimic starvation of trp and 32 leucine, respectively. We show that these drugs block chlamydial growth and induce changes in 33 morphology and transcription consistent with persistence. Importantly, growth inhibition was 34 reversed when the compounds were removed from the medium. With these data, we find that 35 indolmycin and AN3365 are valid tools that can be used to mimic the persistent state independently 36 of IFNγ. 37 Word Count: 248/250 38 39 3 Importance 40The obligate intracellular pathogen Chlamydia trachomatis, although treatable, remains a 41 major public health concern due to rising infection rates. The asymptomatic nature of most 42 Chlamydia infections is hypothesized to be a product of its ability to transition into a slow-growing 43 state referred to as persistence. The most physiologically relevant inducer of persistence is the 44 immune cytokine IFNγ, which in humans activates an enzyme that degrades tryptophan, an 45 essential amino acid that Chlamydia scavenges from the host cell. Unfortunately, the exact timing 46 at which Chlamydia is starved after IFNγ treatment is inexact. To mechanistically study 47 48 at specific times is needed. Here, we demonstrate the capability of tRNA synthetase inhibitors, 49 indolmycin and AN3365, to model persistence independently from the use of IFNγ. These tools 50 will also allow comparisons between amino acid stress responses in this unique bacterium. 51 Word Count: 149/150 52 53Chlamydial diseases are significant causes of morbidity in humans. Chlamydia trachomatis 54 is the leading cause of bacterial sexually transmitted infections in the world. In 2017, the U.S. 55Centers for Disease Control and Prevention ...

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Quantitative Protein Profiling of Chlamydia trachomatis Growth Forms Reveals Defense Strategies Against Tryptophan Starvation

Cited by 26 publications

References 50 publications

Inhibition of tRNA Synthetases Induces Persistence inChlamydia

Inhibition of tRNA Synthetases Induces Persistence inChlamydia

Ixodes scapularis Tick Cells Control Anaplasma phagocytophilum Infection by Increasing the Synthesis of Phosphoenolpyruvate from Tyrosine

Inhibition of tRNA Synthetases Induces Persistence inChlamydia

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