Browse
Submit Data
Databases
API
Help

Dataset Information

14 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Deletion of pknG Abates Reactivation of Latent Mycobacterium tuberculosis in Mice.

ABSTRACT: Eradication of tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), has been a challenge due to its uncanny ability to survive in a dormant state inside host granulomas for decades. Mtb rewires its metabolic and redox regulatory networks to survive in the hostile hypoxic and nutrient-limiting environment, facilitating the formation of drug-tolerant persisters. Previously, we showed that protein kinase G (PknG), a virulence factor required for lysosomal escape, aids in metabolic adaptation, thereby promoting the survival of nonreplicating mycobacteria. Here, we sought to investigate the therapeutic potential of PknG against latent mycobacterium. We show that inhibition of PknG by AX20017 reduces mycobacterial survival in in vitro latency models such as hypoxia, persisters, and nutrient starvation. Targeting PknG enhances the bactericidal activity of the frontline anti-TB drugs in peritoneal macrophages. Deletion of pknG resulted in 5- to 15-fold-reduced survival of Mtb in chronically infected mice treated with anti-TB drugs. Importantly, in the Cornell mouse model of latent TB, the deletion of pknG drastically attenuated Mtb's ability to resuscitate after antibiotic treatment compared with wild-type and complemented strains. This is the first study to investigate the sterilizing activity of pknG deletion and inhibition for adjunct therapy against latent TB in a preclinical model. Collectively, these results suggest that PknG may be a promising drug target for adjunct therapy to shorten the treatment duration and reduce disease relapse.

SUBMITTER: Khan MZ

PROVIDER: S-EPMC8097433 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Metronidazole prevents reactivation of latent Mycobacterium tuberculosis infection in macaques.

Project description:Targeting Mycobacterium tuberculosis bacilli in low-oxygen microenvironments, such as caseous granulomas, has been hypothesized to have the potential to shorten therapy for active tuberculosis (TB) and prevent reactivation of latent infection. We previously reported that upon low-dose M. tuberculosis infection, equal proportions of cynomolgus macaques develop active disease or latent infection and that latently infected animals reactivated upon neutralization of TNF. Using this model we now show that chemoprophylaxis of latently infected cynomolgus macaques with 6 mo of isoniazid (INH) effectively prevented anti-TNF antibody-induced reactivation. Similarly, 2-mo treatment of latent animals with a combination of INH and rifampicin (RIF) was highly effective at preventing reactivation disease in this model. Metronidazole (MTZ), which has activity only against anaerobic, nonreplicating bacteria, was as effective as either of these treatments in preventing reactivation of latent infection. Because hypoxic lesions also occur during active TB, we further showed that addition of MTZ to INH/RIF effectively treated animals with active TB within 2 mo. Healing lesions were associated with distinct changes in cellular pathology, with a shift toward increasingly fibrotic and calcified lesions. Our data in the nonhuman primate model of active and latent TB supports targeting bacteria in hypoxic environments for preventing reactivation of latent infection and possibly shortening the duration of therapy in active TB.

| S-EPMC3435210 | biostudies-literature

Deletion of kasB in Mycobacterium tuberculosis causes loss of acid-fastness and subclinical latent tuberculosis in immunocompetent mice.

Project description:Mycobacterium tuberculosis, the causative agent of tuberculosis, has two distinguishing characteristics: its ability to stain acid-fast and its ability to cause long-term latent infections in humans. Although this distinctive staining characteristic has often been attributed to its lipid-rich cell wall, the specific dye-retaining components were not known. Here we report that targeted deletion of kasB, one of two M. tuberculosis genes encoding distinct beta-ketoacyl- acyl carrier protein synthases involved in mycolic acid synthesis, results in loss of acid-fast staining. Biochemical and structural analyses revealed that the DeltakasB mutant strain synthesized mycolates with shorter chain lengths. An additional and unexpected outcome of kasB deletion was the loss of ketomycolic acid trans-cyclopropanation and a drastic reduction in methoxymycolic acid trans-cyclopropanation, activities usually associated with the trans-cyclopropane synthase CmaA2. Although deletion of kasB also markedly altered the colony morphology and abolished classic serpentine growth (cording), the most profound effect of kasB deletion was the ability of the mutant strain to persist in infected immunocompetent mice for up to 600 days without causing disease or mortality. This long-term persistence of DeltakasB represents a model for studying latent M. tuberculosis infections and suggests that this attenuated strain may represent a valuable vaccine candidate against tuberculosis.

| S-EPMC1829279 | biostudies-literature

Antiretroviral therapy timing impacts latent tuberculosis infection reactivation in a Mycobacterium tuberculosis/SIV coinfection model.

Project description:Studies using the nonhuman primate model of Mycobacterium tuberculosis/simian immunodeficiency virus coinfection have revealed protective CD4+ T cell-independent immune responses that suppress latent tuberculosis infection (LTBI) reactivation. In particular, chronic immune activation rather than the mere depletion of CD4+ T cells correlates with reactivation due to SIV coinfection. Here, we administered combinatorial antiretroviral therapy (cART) 2 weeks after SIV coinfection to study whether restoration of CD4+ T cell immunity occurred more broadly, and whether this prevented reactivation of LTBI compared to cART initiated 4 weeks after SIV. Earlier initiation of cART enhanced survival, led to better control of viral replication, and reduced immune activation in the periphery and lung vasculature, thereby reducing the rate of SIV-induced reactivation. We observed robust CD8+ T effector memory responses and significantly reduced macrophage turnover in the lung tissue. However, skewed CD4+ T effector memory responses persisted and new TB lesions formed after SIV coinfection. Thus, reactivation of LTBI is governed by very early events of SIV infection. Timing of cART is critical in mitigating chronic immune activation. The potential novelty of these findings mainly relates to the development of a robust animal model of human M. tuberculosis/HIV coinfection that allows the testing of underlying mechanisms.

| S-EPMC8803324 | biostudies-literature

SIV and Mycobacterium tuberculosis synergy within the granuloma accelerates the reactivation pattern of latent tuberculosis.

Project description:Human immunodeficiency virus infection is the most common risk factor for severe forms of tuberculosis (TB), regardless of CD4 T cell count. Using a well-characterized cynomolgus macaque model of human TB, we compared radiographic, immunologic and microbiologic characteristics of early (subclinical) reactivation of latent M. tuberculosis (Mtb) infection among animals subsequently infected with simian immunodeficiency virus (SIV) or who underwent anti-CD4 depletion by a depletion antibody. CD4 depleted animals had significantly fewer CD4 T cells within granulomas compared to Mtb/SIV co-infected and Mtb-only control animals. After 2 months of treatment, subclinical reactivation occurred at similar rates among CD4 depleted (5 of 7 animals) and SIV infected animals (4 of 8 animals). However, SIV-induced reactivation was associated with more dissemination of lung granulomas that were permissive to Mtb growth resulting in greater bacterial burden within granulomas compared to CD4 depleted reactivators. Granulomas from Mtb/SIV animals displayed a more robust T cell activation profile (IFN-α, IFN-γ, TNF, IL-17, IL-2, IL-10, IL-4 and granzyme B) compared to CD4 depleted animals and controls though these effectors did not protect against reactivation or dissemination, but instead may be related to increased viral and/or Mtb antigens. SIV replication within the granuloma was associated with reactivation, greater overall Mtb growth and reduced Mtb killing resulting in greater overall Mtb burden. These data support that SIV disrupts protective immune responses against latent Mtb infection beyond the loss of CD4 T cells, and that synergy between SIV and Mtb occurs within granulomas.

| S-EPMC7419014 | biostudies-literature

PknG senses amino acid availability to control metabolism and virulence of Mycobacterium tuberculosis.

Project description:Sensing and response to changes in nutrient availability are essential for the lifestyle of environmental and pathogenic bacteria. Serine/threonine protein kinase G (PknG) is required for virulence of the human pathogen Mycobacterium tuberculosis, and its putative substrate GarA regulates the tricarboxylic acid cycle in M. tuberculosis and other Actinobacteria by protein-protein binding. We sought to understand the stimuli that lead to phosphorylation of GarA, and the roles of this regulatory system in pathogenic and non-pathogenic bacteria. We discovered that M. tuberculosis lacking garA was severely attenuated in mice and macrophages and furthermore that GarA lacking phosphorylation sites failed to restore the growth of garA deficient M. tuberculosis in macrophages. Additionally we examined the impact of genetic disruption of pknG or garA upon protein phosphorylation, nutrient utilization and the intracellular metabolome. We found that phosphorylation of GarA requires PknG and depends on nutrient availability, with glutamate and aspartate being the main stimuli. Disruption of pknG or garA caused opposing effects on metabolism: a defect in glutamate catabolism or depletion of intracellular glutamate, respectively. Strikingly, disruption of the phosphorylation sites of GarA was sufficient to recapitulate defects caused by pknG deletion. The results suggest that GarA is a cellular target of PknG and the metabolomics data demonstrate that the function of this signaling system is in metabolic regulation. This function in amino acid homeostasis is conserved amongst the Actinobacteria and provides an example of the close relationship between metabolism and virulence.

| S-EPMC5448819 | biostudies-literature

Characterization of a novel necrotic granuloma model of latent tuberculosis infection and reactivation in mice.

Project description:We sought to develop and characterize a novel paucibacillary model in mice, which develops necrotic lung granulomas after infection with Mycobacterium tuberculosis. Six weeks after aerosol immunization with recombinant Mycobacterium bovis bacillus Calmette-Guerin overexpressing the 30-kDa antigen, C3HeB/FeJ mice were aerosol infected with M. tuberculosis H37Rv. Six weeks later, mice were treated with one of three standard regimens for latent tuberculosis infection or tumor necrosis factor (TNF)-neutralizing antibody. Mouse lungs were analyzed by histological features, positron emission tomography/computed tomography, whole-genome microarrays, and RT-PCR. Lungs and sera were studied by multiplex enzyme-linked immunosorbent assays. Paucibacillary infection was established, recapitulating the sterilizing activities of human latent tuberculosis infection regimens. TNF neutralization led to increased lung bacillary load, disrupted granuloma architecture with expanded necrotic foci and reduced tissue hypoxia, and accelerated animal mortality. TNF-neutralized mouse lungs and sera showed significant up-regulation of interferon γ, IL-1β, IL-6, IL-10, chemokine ligands 2 and 3, and matrix metalloproteinase genes. Clinical and microbiological reactivation of paucibacillary infection by TNF neutralization was associated with reduced hypoxia in lung granulomas and induction of matrix metalloproteinases and proinflammatory cytokines. This model may be useful for screening the sterilizing activity of novel anti-tuberculosis drugs, and identifying mycobacterial regulatory and metabolic pathways required for bacillary growth restriction and reactivation.

| S-EPMC4076462 | biostudies-literature

The multistage vaccine H56 boosts the effects of BCG to protect cynomolgus macaques against active tuberculosis and reactivation of latent Mycobacterium tuberculosis infection.

Project description:It is estimated that one-third of the world's population is infected with Mycobacterium tuberculosis. Infection typically remains latent, but it can reactivate to cause clinical disease. The only vaccine, Mycobacterium bovis bacillus Calmette-Guérin (BCG), is largely ineffective, and ways to enhance its efficacy are being developed. Of note, the candidate booster vaccines currently under clinical development have been designed to improve BCG efficacy but not prevent reactivation of latent infection. Here, we demonstrate that administering a multistage vaccine that we term H56 in the adjuvant IC31 as a boost to vaccination with BCG delays and reduces clinical disease in cynomolgus macaques challenged with M. tuberculosis and prevents reactivation of latent infection. H56 contains Ag85B and ESAT-6, which are two of the M. tuberculosis antigens secreted in the acute phase of infection, and the nutrient stress-induced antigen Rv2660c. Boosting with H56/IC31 resulted in efficient containment of M. tuberculosis infection and reduced rates of clinical disease, as measured by clinical parameters, inflammatory markers, and improved survival of the animals compared with BCG alone. Boosted animals showed reduced pulmonary pathology and extrapulmonary dissemination, and protection correlated with a strong recall response against ESAT-6 and Rv2660c. Importantly, BCG/H56-vaccinated monkeys did not reactivate latent infection after treatment with anti-TNF antibody. Our results indicate that H56/IC31 boosting is able to control late-stage infection with M. tuberculosis and contain latent tuberculosis, providing a rationale for the clinical development of H56.

| S-EPMC3248283 | biostudies-literature

Insights from the molecular docking of withanolide derivatives to the target protein PknG from Mycobacterium tuberculosis.

Project description:A crucial virulence factor for intracellular Mycobacterium tuberculosis survival is Protein kinase G (PknG), a eukaryotic-like serinethreonine protein kinase expressed by pathogenic mycobacteria that blocks the intracellular degradation of mycobacteria in lysosomes. Inhibition of PknG results in mycobacterial transfer to lysosomes. Withania somnifera, a reputed herb in ayurvedic medicine, comprises a large number of steroidal lactones known as withanolides which show various pharmacological activities. We describe the docking of 26 withanferin and 14 withanolides from Withania somnifera into the three dimensional structure of PknG of M. tuberculosis using GLIDE. The inhibitor binding positions and affinity were evaluated using scoring functions- Glidescore. The withanolide E, F and D and Withaferin - diacetate 2 phenoxy ethyl carbonate were identified as potential inhibitors of PknG. The available drug molecules and the ligand AX20017 showed hydrogen bond interaction with the aminoacid residues Glu233 and Val235. In addition to Val235 the other amino acids, Gly237, Gln238 and Ser239 are important for withanolide inhibitor recognition via hydrogen bonding mechanisms.

| S-EPMC3169209 | biostudies-literature

Mechanisms of reactivation of latent tuberculosis infection due to SIV coinfection.

Project description:HIV is a major driver of tuberculosis (TB) reactivation. Depletion of CD4+ T cells is assumed to be the basis behind TB reactivation in individuals with latent tuberculosis infection (LTBI) coinfected with HIV. Nonhuman primates (NHPs) coinfected with a mutant simian immunodeficiency virus (SIVΔGY) that does not cause depletion of tissue CD4+ T cells during infection failed to reactivate TB. To investigate the contribution of CD4+ T cell depletion relative to other mechanisms of SIV-induced reactivation of LTBI, we used CD4R1 antibody to deplete CD4+ T cells in animals with LTBI without lentiviral infection. The mere depletion of CD4+ T cells during LTBI was insufficient in generating reactivation of LTBI. Instead, direct cytopathic effects of SIV resulting in chronic immune activation, along with the altered effector T cell phenotypes and dysregulated T cell homeostasis, were likely mediators of reactivation of LTBI. These results revealed important implications for TB control in HIV-coinfected individuals.

| S-EPMC6877319 | biostudies-literature

Transcriptional changes during Mycobacterium tuberculosis reactivation from persistence

Project description:We observe that M. tuberculosis reactivation is associated with a global gene expression program that defines the initiation of an ordered programmed reactivation process in the lag phase.

2016-12-31 | GSE83814 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data