Host-pathogen genetic interactions underlie tuberculosis susceptibility

Smith, Clare M.; Baker, Richard E.; Proulx, Megan K.; Mishra, Bibhuti B.; Long, Jarukit E.; Kiritsy, Michael C.; Bellerose, Michelle M.; Olive, Andrew J.; Murphy, Kenan C.; Papavinasasundaram, Kadamba; Boehm, Frederick J.; Reames, Charlotte J; Sassetti, Christopher M.

doi:10.1101/2020.12.01.405514

Cited by 5 publications

(6 citation statements)

References 96 publications

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“…We examined the predicted operon of one other cAMP-binding protein, the transcription factor CRP MT , and found that only a handful of these genes were differentially expressed in a cAMP-dependent and/or Rv1625c-dependent manner during growth in cholesterol media (Fig 8). Notably, three of these genes are required for optimal growth of Mtb in cholesterol media and/or in mouse models of TB, but are not directly involved in cholesterol side chain or ring breakdown [12,45]. Most of the remaining genes do not have established functions, making it difficult to predict how changes in their expression could impact specific aspects of Mtb physiology.…”

Section: Plos Pathogensmentioning

confidence: 99%

“…Mtb completely degrades cholesterol into two-and three-carbon intermediates that are metabolized for energy production or serve as biosynthetic precursors of cell wall or virulence lipids [6]. In animal models, Mtb requires cholesterol metabolism to maintain optimal chronic lung infection [7][8][9][10][11] and cholesterol utilization was recently found to belong to a set of "core virulence functions" required for Mtb survival in vivo across a genetically diverse panel of mice [12]. Furthermore, it was recently demonstrated that a multi-drug resistant strain of Mtb is more dependent on cholesterol for growth than the H37Rv reference strain [13].…”

Section: Introductionmentioning

confidence: 99%

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Pharmacological and genetic activation of cAMP synthesis disrupts cholesterol utilization in Mycobacterium tuberculosis

et al. 2022

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There is a growing appreciation for the idea that bacterial utilization of host-derived lipids, including cholesterol, supports Mycobacterium tuberculosis (Mtb) pathogenesis. This has generated interest in identifying novel antibiotics that can disrupt cholesterol utilization by Mtb in vivo. Here we identify a novel small molecule agonist (V-59) of the Mtb adenylyl cyclase Rv1625c, which stimulates 3’, 5’-cyclic adenosine monophosphate (cAMP) synthesis and inhibits cholesterol utilization by Mtb. Similarly, using a complementary genetic approach that induces bacterial cAMP synthesis independent of Rv1625c, we demonstrate that inducing cAMP synthesis is sufficient to inhibit cholesterol utilization in Mtb. Although the physiological roles of individual adenylyl cyclase enzymes in Mtb are largely unknown, here we demonstrate that the transmembrane region of Rv1625c is required during cholesterol metabolism. Finally, the pharmacokinetic properties of Rv1625c agonists have been optimized, producing an orally-available Rv1625c agonist that impairs Mtb pathogenesis in infected mice. Collectively, this work demonstrates a role for Rv1625c and cAMP signaling in controlling cholesterol metabolism in Mtb and establishes that cAMP signaling can be pharmacologically manipulated for the development of new antibiotic strategies.

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Section: Plos Pathogensmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pharmacological and genetic activation of cAMP synthesis disrupts cholesterol utilization in Mycobacterium tuberculosis

et al. 2022

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“…To place the variability in genetic requirements we observed between bacterial isolates from different phylogenetic lineages into broader biological context, we considered a recently published TnSeq study which investigated Mtb requirements for infection across genetically and immunologically diverse mouse backgrounds 63 . In this study, an H37Rv transposon library was used to infect a panel of 60 mouse genotypes encompassing strains from the Collaborative Cross collection and mice with specific immunological deficits, such as IFNγ knockout.…”

Section: Functional Genomic Analysis Of Mtb Strains During Infectionmentioning

confidence: 99%

Multiplexed strain phenotyping defines consequences of genetic diversity in Mycobacterium tuberculosis for infection and vaccination outcomes

Carey

Wang

Cicchetti

et al. 2022

Preprint

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There is growing evidence that genetic diversity in Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, contributes to the outcomes of infection and public health interventions, such as vaccination. Epidemiological studies suggest that among the phylogeographic lineages of Mtb, strains belonging to Lineage 2 (L2) are associated with concerning clinical features including hypervirulence, treatment failure, and vaccine escape. The global expansion and increasing prevalence of L2 has been attributed to the selective advantage conferred by these characteristics, yet confounding host and environmental factors make it difficult to identify the bacterial determinants driving these associations in human studies. Here, we developed a molecular barcoding strategy to facilitate high-throughput, experimental phenotyping of Mtb clinical isolates. This approach allowed us to characterize growth dynamics for a panel of genetically diverse Mtb strains during infection and after vaccination in the mouse model. We found that L2 strains exhibit distinct growth dynamics in vivo and are resistant to the immune protection conferred by Bacillus Calmette-Guerin (BCG) vaccination. The latter finding corroborates epidemiological observations and demonstrates that mycobacterial features contribute to vaccine efficacy. To investigate the genetic and biological basis of L2 strains' distinctive phenotypes, we performed variant analysis, transcriptional studies, and genome-wide transposon sequencing. We identified functional genetic changes across multiple stress- and host- response pathways in a representative L2 strain that are associated with variants in regulatory genes. These adaptive changes may underlie the distinct clinical characteristics and epidemiological success of this lineage.

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“…A non-redundant role for RodA in protection against cell wall damage. The contribution of RodAMtb to M. tuberculosis survival in different in vivo models (29,(35)(36)(37)39) and the requirement for RodAMsm in the damage-induced sidewall shift in M. smegmatis peptidoglycan synthesis (Fig. 4) suggested that the enzyme could play a non-redundant role in protecting against cell wall stress.…”

Section: Roda But Not Apbps Contributes To Redistribution Of Peptidoglycan Synthesismentioning

confidence: 99%

“…Why have these organisms retained enzymatically-redundant systems for peptidoglycan synthesis? One clue may arise from work with the human pathogen M. tuberculosis, where RodA and the aPBPs individually contribute to survival in immune cells, some mouse backgrounds, and in a guinea pig model (29,(35)(36)(37)(38)(39). These observations suggest that RodA and the aPBPs play unique roles in protecting mycobacteria from stress.…”

Section: Introductionmentioning

confidence: 99%

Cell wall damage reveals spatial flexibility in peptidoglycan synthesis and a non-redundant role for RodA in mycobacteria

Melzer

Kado

García‐Heredia

et al. 2021

Preprint

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Cell wall peptidoglycan is a heteropolymeric mesh that protects the bacteria from internal turgor and external insults. In many rod-shaped bacteria, peptidoglycan synthesis for normal growth is achieved by two distinct pathways: the Rod complex, comprised of MreB, RodA and a cognate class B PBP, and the class A PBPs. In contrast to laterally-growing bacteria, pole-growing mycobacteria do not encode an MreB homolog and do not require SEDS protein RodA for in vitro growth. However, RodA contributes to survival of Mycobacterium tuberculosis in some infection models, suggesting that the protein could have a stress-dependent role in maintaining cell wall integrity. Under basal conditions, we find here that the subcellular distribution of RodA largely overlaps with that of the aPBP PonA1, and that both RodA and the aPBPs promote polar peptidoglycan assembly. Upon cell wall damage, RodA fortifies M. smegmatis against lysis and, unlike aPBPs, contributes to a shift in peptidoglycan assembly from the poles to the sidewall. Neither RodA nor PonA1 relocalize; instead, the redistribution of nascent cell wall parallels that of peptidoglycan precursor synthase MurG. Our results support a model in which mycobacteria balance polar growth and cell-wide repair via spatial flexibility in precursor synthesis and extracellular insertion.ImportancePeptidoglycan synthesis is a highly successful target for antibiotics. The pathway has been extensively studied in model organisms under laboratory-optimized conditions. In natural environments, bacteria are frequently under attack. Moreover the vast majority of bacterial species are unlikely to fit a single paradigm because of differences in growth mode and/or envelope structure. Studying cell wall synthesis under non-optimal conditions and in non-standard species may improve our understanding of pathway function and suggest new inhibition strategies. Mycobacterium smegmatis, a relative of several notorious human and animal pathogens, has an unusual polar growth mode and multi-layered envelope. In this work we challenged M. smegmatis with cell wall-damaging enzymes to characterize the roles of cell wall-building enzymes when the bacterium is under attack.

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Host-pathogen genetic interactions underlie tuberculosis susceptibility

Cited by 5 publications

References 96 publications

Pharmacological and genetic activation of cAMP synthesis disrupts cholesterol utilization in Mycobacterium tuberculosis

Pharmacological and genetic activation of cAMP synthesis disrupts cholesterol utilization in Mycobacterium tuberculosis

Multiplexed strain phenotyping defines consequences of genetic diversity in Mycobacterium tuberculosis for infection and vaccination outcomes

Cell wall damage reveals spatial flexibility in peptidoglycan synthesis and a non-redundant role for RodA in mycobacteria

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