Lactate Alters Metabolism in Human Macrophages and Improves Their Ability to Kill Mycobacterium tuberculosis

In order to mount an appropriate immune response to infection, the macrophage must alter its metabolism by increasing aerobic glycolysis and concomitantly decreasing oxidative phosphorylation; a process known as the Warburg effect. Consequently, lactate, the end-product of glycolysis, accumulates in the extracellular environment. The subsequent effect of lactate on surrounding macrophages is poorly understood. Mycobacterium tuberculosis (Mtb), the causative organism of Tuberculosis (TB), is phagocytosed by macrophages in the airways. Mtb infected macrophages upregulate aerobic glycolysis and effector functions to try to kill the bacteria. Our lab has previously shown that human macrophages produce lactate in response to infection with Mtb. Although lactate has largely been considered a waste product of aerobic glycolysis, we hypothesised that the presence of extracellular lactate would impact subsequent immunometabolic responses and modulate macrophage function. We demonstrate that the presence of exogenous lactate has an immediate effect on the cellular metabolism of resting human macrophages; causing a decrease in extracellular acidification rate (ECAR; analogous to the rate of glycolysis) and an increase in the oxygen consumption rate (OCR; analogous to oxidative phosphorylation). When lactate-treated macrophages were stimulated with Mtb or LPS, glycolysis proceeds to increase immediately upon stimulation but oxidative phosphorylation remains stable compared with untreated cells that display a decrease in OCR. This resulted in a significantly reduced ECAR/OCR ratio early in response to stimulation. Since altered metabolism is intrinsically linked to macrophage function, we examined the effect of lactate on macrophage cytokine production and ability to kill Mtb. Lactate significantly reduced the concentrations of TNF and IL-1β produced by human macrophages in response to Mtb but did not alter IL-10 and IL-6 production. In addition, lactate significantly improved bacillary clearance in human macrophages infected with Mtb, through a mechanism that is, at least in part, mediated by promoting autophagy. These data indicate that lactate, the product of glycolysis, has a negative feedback effect on macrophages resulting in an attenuated glycolytic shift upon subsequent stimulation and reduced pro-inflammatory cytokine production. Interestingly, this pro-resolution effect of lactate is associated with increased capacity to kill Mtb.

Download Full-text

Enhanced Proinflammatory Cytokine Production and Immunometabolic Impairment of NK Cells Exposed to Mycobacterium tuberculosis and Cigarette Smoke

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.799276 ◽

2022 ◽

Vol 11 ◽

Author(s):

Yafei Rao ◽

Xiaoyan Gai ◽

Yanqing Le ◽

Jing Xiong ◽

Yujia Liu ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Oxidative Phosphorylation ◽

Nk Cells ◽

Cigarette Smoke ◽

Proinflammatory Cytokine ◽

Cytokine Production ◽

Nk Cell ◽

Proinflammatory Cytokine Production ◽

Cell Subpopulations

AimSmoker COPD patients with chest radiological signs of prior tuberculosis (TB) showed more severe lung damage, but the mechanisms remain unclear. Emerging evidence has implicated NK cells in the pathogenesis of both COPD and TB. The purpose of this study was to delineate the profile and cytokine production of NK-cell subpopulations and their immunometabolic changes after exposure to both cigarette smoke (CS) and Mycobacterium tuberculosis(MTB).MethodsWe profiled NK-cell subpopulations in terms of percentage and cytokine production by flow cytometry in smoker patients with pulmonary TB (PTB). In an in vitro coexposure model, we investigated proinflammatory cytokine production, glycolytic influx, and oxidative phosphorylation of NK cells under CS extract (CSE) and PPD costimulation.ResultsPeripheral blood NK cells in smoker patients with active PTB (CS+PTB group) showed altered proportion of subpopulations and excessive proinflammatory cytokine expressions. In vitro, CSE- and PPD-coexposed NK-92 cells displayed enhanced proinflammatory cytokine production, concurrent with decreased glycolytic influx and oxidative phosphorylation.ConclusionSmoker patients with active PTB showed enhanced proinflammatory cytokine expression within altered NK cell subpopulations. CSE and PPD coexposure induced heightened cytokine production concurrent with impaired cell metabolism in NK cells. These novel data suggest a potential role of NK cells in the pathogenesis of lung injury in subjects with coexposure to CS and TB.

Download Full-text

Faculty Opinions recommendation of ATP stimulates human macrophages to kill intracellular virulent Mycobacterium tuberculosis via calcium-dependent phagosome-lysosome fusion.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1000922.13563 ◽

2001 ◽

Author(s):

Kwang-Sik Kim

Keyword(s):

Mycobacterium Tuberculosis ◽

Human Macrophages ◽

Calcium Dependent

Download Full-text

Faculty Opinions recommendation of The Mycobacterium tuberculosis phagosome in human macrophages is isolated from the host cell cytoplasm.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1009414.126157 ◽

2002 ◽

Author(s):

Sergio Grinstein

Keyword(s):

Mycobacterium Tuberculosis ◽

Host Cell ◽

Cell Cytoplasm ◽

Human Macrophages ◽

Host Cell Cytoplasm

Download Full-text

Faculty Opinions recommendation of Nitrite produced by Mycobacterium tuberculosis in human macrophages in physiologic oxygen impacts bacterial ATP consumption and gene expression.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718151477.793503311 ◽

2015 ◽

Author(s):

Elizabeth Boon

Keyword(s):

Gene Expression ◽

Mycobacterium Tuberculosis ◽

Human Macrophages

Download Full-text

Faculty Opinions recommendation of Mycobacterium tuberculosis triggers host type I IFN signaling to regulate IL-1β production in human macrophages.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.719454537.793504130 ◽

2015 ◽

Author(s):

Padmini Salgame ◽

Archana Gopalakrishnan

Keyword(s):

Mycobacterium Tuberculosis ◽

Type I ◽

Type I Ifn ◽

Human Macrophages ◽

Host Type

Download Full-text

Mycobacterium tuberculosis Binds Human Serum Amyloid A and the Interaction Modulates the Colonization of Human Macrophages and the Transcriptional Response of the Pathogen

Cells ◽

10.3390/cells10051264 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1264

Author(s):

Malwina Kawka ◽

Anna Brzostek ◽

Katarzyna Dzitko ◽

Jakub Kryczka ◽

Radosław Bednarek ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Serum Amyloid A ◽

Acute Phase Protein ◽

Transcriptional Response ◽

Serum Amyloid ◽

Host Protein ◽

Binding Interaction ◽

Human Macrophages ◽

Amyloid A ◽

Transporter Systems

As a very successful pathogen with outstanding adaptive properties, Mycobacterium tuberculosis (Mtb) has developed a plethora of sophisticated mechanisms to subvert host defenses and effectively enter and replicate in the harmful environment inside professional phagocytes, namely, macrophages. Here, we demonstrated the binding interaction of Mtb with a major human acute phase protein, namely, serum amyloid A (SAA1), and identified AtpA (Rv1308), ABC (Rv2477c), EspB (Rv3881c), TB 18.6 (Rv2140c), and ThiC (Rv0423c) membrane proteins as mycobacterial effectors responsible for the pathogen-host protein interplay. SAA1-opsonization of Mtb prior to the infection of human macrophages favored bacterial entry into target phagocytes accompanied by a substantial increase in the load of intracellularly multiplying and surviving bacteria. Furthermore, binding of human SAA1 by Mtb resulted in the up- or downregulation of the transcriptional response of tubercle bacilli. The most substantial changes were related to the increased expression level of the genes of two operons encoding mycobacterial transporter systems, namely, mmpL5/mmpS5 (rv0676c), and rv1217c, rv1218c. Therefore, we postulate that during infection, Mtb-SAA1 binding promotes the infection of host macrophages by tubercle bacilli and modulates the functional response of the pathogen.

Download Full-text

HO-1 Modulates Aerobic Glycolysis through LDH in Prostate Cancer Cells

Antioxidants ◽

10.3390/antiox10060966 ◽

2021 ◽

Vol 10 (6) ◽

pp. 966

Author(s):

Florencia Cascardo ◽

Nicolás Anselmino ◽

Alejandra Páez ◽

Estefanía Labanca ◽

Pablo Sanchis ◽

...

Keyword(s):

Prostate Cancer ◽

Aerobic Glycolysis ◽

Heme Oxygenase 1 ◽

Free Survival ◽

Atp Production ◽

Inflammatory Damage ◽

Extracellular Lactate ◽

Cellular Energetics ◽

Lactate Levels

Prostate cancer (PCa) is the second most diagnosed malignancy and the fifth leading cause of cancer associated death in men worldwide. Dysregulation of cellular energetics has become a hallmark of cancer, evidenced by numerous connections between signaling pathways that include oncoproteins and key metabolic enzymes. We previously showed that heme oxygenase 1 (HO-1), a cellular homeostatic regulator counteracting oxidative and inflammatory damage, exhibits anti-tumoral activity in PCa cells, inhibiting cell proliferation, migration, tumor growth and angiogenesis. The aim of this study was to assess the role of HO-1 on the metabolic signature of PCa. After HO-1 pharmacological induction with hemin, PC3 and C4-2B cells exhibited a significantly impaired cellular metabolic rate, reflected by glucose uptake, ATP production, lactate dehydrogenase (LDH) activity and extracellular lactate levels. Further, we undertook a bioinformatics approach to assess the clinical significance of LDHA, LDHB and HMOX1 in PCa, identifying that high LDHA or low LDHB expression was associated with reduced relapse free survival (RFS). Interestingly, the shortest RFS was observed for PCa patients with low HMOX1 and high LDHA, while an improved prognosis was observed for those with high HMOX1 and LDHB. Thus, HO-1 induction causes a shift in the cellular metabolic profile of PCa, leading to a less aggressive phenotype of the disease.

Download Full-text

Intracellular localisation of Mycobacterium tuberculosis affects efficacy of the antibiotic pyrazinamide

Nature Communications ◽

10.1038/s41467-021-24127-3 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Pierre Santucci ◽

Daniel J. Greenwood ◽

Antony Fearns ◽

Kai Chen ◽

Haibo Jiang ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Host Cell ◽

Combination Chemotherapy ◽

In Vitro Activity ◽

In Vivo Efficacy ◽

Human Macrophages ◽

Ion Microscopy ◽

Intracellular Localisation

AbstractTo be effective, chemotherapy against tuberculosis (TB) must kill the intracellular population of the pathogen, Mycobacterium tuberculosis. However, how host cell microenvironments affect antibiotic accumulation and efficacy remains unclear. Here, we use correlative light, electron, and ion microscopy to investigate how various microenvironments within human macrophages affect the activity of pyrazinamide (PZA), a key antibiotic against TB. We show that PZA accumulates heterogeneously among individual bacteria in multiple host cell environments. Crucially, PZA accumulation and efficacy is maximal within acidified phagosomes. Bedaquiline, another antibiotic commonly used in combined TB therapy, enhances PZA accumulation via a host cell-mediated mechanism. Thus, intracellular localisation and specific microenvironments affect PZA accumulation and efficacy. Our results may explain the potent in vivo efficacy of PZA, compared to its modest in vitro activity, and its critical contribution to TB combination chemotherapy.

Download Full-text

AB0108 IRAK4 INHIBITION SUPPRESSES PROINFLAMMATORY CYTOKINE PRODUCTION FROM HUMAN MACROPHAGES STIMULATED WITH SYNOVIAL FLUID FROM RHEUMATOID ARTHRITIS PATIENTS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.3793 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1353.2-1353

Author(s):

A. Yadon ◽

D. Ruelas ◽

G. Min-Oo ◽

J. Taylor ◽

M. R. Warr

Keyword(s):

Rheumatoid Arthritis ◽

Synovial Fluid ◽

Signaling Pathways ◽

Proinflammatory Cytokines ◽

Proinflammatory Cytokine ◽

Cytokine Production ◽

Interleukin 1 ◽

Proinflammatory Cytokine Production ◽

Human Macrophages ◽

Percent Suppression

Background:Rheumatoid arthritis (RA) is characterized by chronic, uncontrolled joint inflammation and tissue destruction. Macrophages are thought to be key mediators in both the initiation and perpetuation of this pathology.1,2The RA synovium contains a complex inflammatory milieu that can stimulate macrophage-dependent production of proinflammatory cytokines through multiple signaling pathways.1,2Existing evidence indicates that toll-like receptors (TLRs) and interleukin-1 receptors (IL-1R) along with their agonists, damage-associated molecular patterns (DAMPs) and IL-1β, are highly expressed in RA joints and are important mediators of synovial macrophage activation and proinflammatory cytokine production.1-9IRAK4 (interleukin-1 receptor-associated kinase 4) is a serine/threonine kinase that facilitates TLR and IL-1R signaling in many cell types, including macrophages.10IRAK4 inhibition represents an opportunity to reduce proinflammatory cytokine production in the joints of patients with RA.Objectives:To investigate the effect of a highly selective IRAK4 inhibitor on proinflammatory cytokine production from human macrophages stimulated with synovial fluid from patients with RA.Methods:Primary human monocytes from 2 independent donors were differentiated for 6 days with granulocyte-macrophage colony-stimulating factor (GM-CSF) to generate human monocyte-derived macrophages (hMDMs). hMDMs were then pretreated with an IRAK4 inhibitor for 1 hour and subsequently stimulated for 24 hours with RA synovial fluid from 5 patients. Culture supernatants were then assessed for secretion of proinflammatory cytokines by MesoScale Discovery.Results:RA synovial fluid stimulation of hMDMs resulted in the production of several proinflammatory cytokines, including IL-6, IL-8, and TNFα. Pretreatment of hMDMs with an IRAK4 inhibitor resulted in the dose-dependent inhibition of IL-6, IL-8, and TNFα production, with an average EC50± SD of 27 ± 31, 26 ± 41, and 28 ± 22 nM, respectively. Maximal percent suppression ± SD of IL-6, IL-8, and TNFα were 76 ± 8.8, 73 ± 15, and 77 ± 13, respectively. To evaluate the specific IRAK4-dependent signaling pathways mediating this response, hMDMs were pretreated with inhibitors of TLR4 (TAK242) and IL-1R (IL-1RA) prior to stimulation with RA synovial fluid. Both TAK242 and IL-1RA inhibited proinflammatory cytokine production. For TAK242, maximal percent suppression ± SD of IL-6, IL-8, and TNFα were 39 ± 25, 48 ± 24, and 50 ± 21, respectively. For IL-1RA maximal percent suppression ± SD of IL-6, IL-8, and TNFα were 18 ± 18, 20 ± 23, and 16 ± 18, respectively. The broad range of inhibition across each stimulation highlights the complexity and variability in the signaling pathways mediating proinflammatory cytokine production from hMDMs stimulated with RA synovial fluid, but demonstrates that RA synovial fluid can stimulate proinflammatory cytokine production in hMDMs, at least partly, through IRAK4-dependent pathways.Conclusion:This work demonstrates that IRAK4 inhibition can suppress proinflammatory cytokine production from macrophages stimulated with synovial fluid from patients with RA and supports a potential pathophysiological role for IRAK4 in perpetuating chronic inflammation in RA.References:[1]Smolen JS, et al.Nat Rev Dis Primers.2018;4:18001.[2]Udalova IA, et al.Nat Rev Rheumatol.2016;12(8):472-485.[3]Joosten LAB, et al.Nat Rev Rheumatol.2016;12(6):344-357.[4]Huang QQ, Pope RM.Curr Rheumatol Rep.2009;11(5):357-364.[5]Roh JS, Sohn DH.Immune Netw.2018;18(4):e27.[6]Sacre SM, et al.Am J Pathol.2007;170(2):518-525.[7]Ultaigh SNA, et al.Arthritis Res Ther.2011;13(1):R33.[8]Bottini N, Firestein GS.Nat Rev Rheumatol.2013;9(1):24-33.[9]Firestein GS, McInnes IB.Immunity.2017;46(2):183-196.[10]Janssens S, Beyaert R.Mol Cell.2003;11(2):293-302.Disclosure of Interests:Adam Yadon Employee of: Gilead, Debbie Ruelas Employee of: Gilead, Gundula Min-Oo Employee of: Gilead, James Taylor Employee of: Gilead, Matthew R. Warr Employee of: Gilead

Download Full-text