Tissue metabolic changes drive cytokine responses to Mycobacterium tuberculosis

Cellular metabolism can influence host immune responses to Mycobacterium tuberculosis (Mtb). Using a systems biology approach, differential expression of 292 metabolic genes involved in glycolysis, glutathione, pyrimidine and inositol phosphate pathways was evident at the site of a human tuberculin skin test challenge in patients with active tuberculosis infection. For 28 metabolic genes, we identified single nucleotide polymorphisms (SNPs) that were trans-acting for in vitro cytokine responses to Mtb stimulation, including glutathione and pyrimidine metabolism genes that alter production of Th1 and Th17 cytokines. Our findings identify novel therapeutic targets in host metabolism that may shape protective immunity to tuberculosis

Rewiring cellular metabolism via the AKT/mTOR pathway contributes to host defence against Mycobacterium tuberculosis in human and murine cells

Contains fulltext : 171426.pdf (publisher's version ) (Open Access)Cells in homeostasis metabolize glucose mainly through the tricarboxylic acid cycle and oxidative phosphorylation, while activated cells switch their basal metabolism to aerobic glycolysis. In this study, we examined whether metabolic reprogramming toward aerobic glycolysis is important for the host response to Mycobacterium tuberculosis (Mtb). Through transcriptional and metabolite analysis we show that Mtb induces a switch in host cellular metabolism toward aerobic glycolysis in human peripheral blood mononuclear cells (PBMCs). The metabolic switch is TLR2 dependent but NOD2 independent, and is mediated in part through activation of the AKT-mTOR (mammalian target of rapamycin) pathway. We show that pharmacological inhibition of the AKT/mTOR pathway inhibits cellular responses to Mtb both in vitro in human PBMCs, and in vivo in a model of murine tuberculosis. Our findings reveal a novel regulatory layer of host responses to Mtb that will aid understanding of host susceptibility to Mtb, and which may be exploited for host-directed therapy

Impact of Intermediate Hyperglycemia and Diabetes on Immune Dysfunction in Tuberculosis

Supplementary Data: Supplementary materials are available at Clinical Infectious Diseases online at https://academic.oup.com/cid/article/72/1/69/5857148#274319223 . Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author.Copyright © The Author(s) 2020. Background: People with diabetes have an increased risk of developing active tuberculosis (TB) and are more likely to have poor TB-treatment outcomes, which may impact on control of TB as the prevalence of diabetes is increasing worldwide. Blood transcriptomes are altered in patients with active TB relative to healthy individuals. The effects of diabetes and intermediate hyperglycemia (IH) on this transcriptomic signature were investigated to enhance understanding of immunological susceptibility in diabetes-TB comorbidity. Methods: Whole blood samples were collected from active TB patients with diabetes (glycated hemoglobin [HbA1c] ≥6.5%) or IH (HbA1c = 5.7% to <6.5%), TB-only patients, and healthy controls in 4 countries: South Africa, Romania, Indonesia, and Peru. Differential blood gene expression was determined by RNA-seq (n = 249). Results: Diabetes increased the magnitude of gene expression change in the host transcriptome in TB, notably showing an increase in genes associated with innate inflammatory and decrease in adaptive immune responses. Strikingly, patients with IH and TB exhibited blood transcriptomes much more similar to patients with diabetes-TB than to patients with only TB. Both diabetes-TB and IH-TB patients had a decreased type I interferon response relative to TB-only patients. Conclusions: Comorbidity in individuals with both TB and diabetes is associated with altered transcriptomes, with an expected enhanced inflammation in the presence of both conditions, but also reduced type I interferon responses in comorbid patients, suggesting an unexpected uncoupling of the TB transcriptome phenotype. These immunological dysfunctions are also present in individuals with IH, showing that altered immunity to TB may also be present in this group. The TB disease outcomes in individuals with IH diagnosed with TB should be investigated further.European Union’s Seventh Framework Programme (FP7 2007-2013 - Health) under grant agreement No 305279

Metformin enhances anti-mycobacterial responses by educating CD8+ T-cell immunometabolic circuits

10.1038/s41467-020-19095-zNature Communications111522

Metformin Alters Human Host Responses to Mycobacterium tuberculosis in Healthy Subjects

BACKGROUND: Metformin, the most widely administered diabetes drug, has been proposed as a candidate adjunctive host-directed therapy for tuberculosis, but little is known about its effects on human host responses to Mycobacterium tuberculosis. METHODS: We investigated in vitro and in vivo effects of metformin in humans. RESULTS: Metformin added to peripheral blood mononuclear cells from healthy volunteers enhanced in vitro cellular metabolism while inhibiting the mammalian target of rapamycin targets p70S6K and 4EBP1, with decreased cytokine production and cellular proliferation and increased phagocytosis activity. Metformin administered to healthy human volunteers led to significant downregulation of genes involved in oxidative phosphorylation, mammalian target of rapamycin signaling, and type I interferon response pathways, particularly following stimulation with M. tuberculosis, and upregulation of genes involved in phagocytosis and reactive oxygen species production was increased. These in vivo effects were accompanied by a metformin-induced shift in myeloid cells from classical to nonclassical monocytes. At a functional level, metformin lowered ex vivo production of tumor necrosis factor alpha, interferon gamma, and interleukin 1beta but increased phagocytosis activity and reactive oxygen species production. CONCLUSION: Metformin has a range of potentially beneficial effects on cellular metabolism, immune function, and gene transcription involved in innate host responses to M. tuberculosis