Sirtuin 3 Downregulation in Mycobacterium tuberculosis-Infected Macrophages Reprograms Mitochondrial Metabolism and Promotes Cell Death

ABSTRACT Mycobacterium tuberculosis induces metabolic reprogramming in macrophages like the Warburg effect. This enhances antimicrobial performance at the expense of increased inflammation, which may promote a pathogen-permissive host environment. Since the NAD+-dependent protein deacetylase Sirtuin 3 (SIRT3) is an important regulator of mitochondrial metabolism and cellular redox homeostasis, we hypothesized that SIRT3 modulation mediates M. tuberculosis-induced metabolic reprogramming. Infection of immortalized and primary murine macrophages resulted in reduced levels of SIRT3 mRNA and protein and perturbation of SIRT3-regulated enzymes in the tricarboxylic acid cycle, electron transport chain, and glycolytic pathway. These changes were associated with increased reactive oxygen species and reduced antioxidant scavenging, thereby triggering mitochondrial stress and macrophage cell death. Relevance to tuberculosis disease in vivo was indicated by greater bacterial burden and immune pathology in M. tuberculosis-infected Sirt3−/− mice. CD11b+ lung leukocytes isolated from infected Sirt3−/− mice showed decreased levels of enzymes involved in central mitochondrial metabolic pathways, along with increased reactive oxygen species. Bacterial burden was also greater in lungs of LysMcreSirt3L2/L2 mice, demonstrating the importance of macrophage-specific SIRT3 after infection. These results support the model of SIRT3 as a major upstream regulatory factor, leading to metabolic reprogramming in macrophages by M. tuberculosis. IMPORTANCE Tuberculosis, the disease caused by the bacterium M. tuberculosis, remains one of the top 10 causes of death worldwide. Macrophages, the first cells to encounter M. tuberculosis and critical for defense against infection, are hijacked by M. tuberculosis as a protected growth niche. M. tuberculosis-infected macrophages undergo metabolic reprogramming where key mitochondrial pathways are modulated, but the mechanisms driving this metabolic shift is unknown. Our study demonstrates that M. tuberculosis downregulates Sirtuin 3 (SIRT3), an important regulator of mitochondrial metabolism, leading to SIRT3-dependent transcriptional downregulation of mitochondrial metabolic proteins, which is followed by oxidative stress and macrophage necrosis. This study identifies SIRT3 modulation as a key event in M. tuberculosis-induced metabolic reprograming in macrophages that defend against tuberculosis.

Download Full-text

Inhibition of Fatty Acid Oxidation Promotes Macrophage Control of Mycobacterium tuberculosis

mBio ◽

10.1128/mbio.01139-20 ◽

2020 ◽

Vol 11 (4) ◽

Cited By ~ 3

Author(s):

Pallavi Chandra ◽

Li He ◽

Matthew Zimmerman ◽

Guozhe Yang ◽

Stefan Köster ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Mycobacterium Tuberculosis ◽

Fatty Acid ◽

Nadph Oxidase ◽

Reactive Oxygen ◽

Metabolic Reprogramming ◽

Acid Oxidation ◽

Oxygen Species ◽

Content Type ◽

Mitochondrial Fatty Acid

ABSTRACT Macrophage activation involves metabolic reprogramming to support antimicrobial cellular functions. How these metabolic shifts influence the outcome of infection by intracellular pathogens remains incompletely understood. Mycobacterium tuberculosis (Mtb) modulates host metabolic pathways and utilizes host nutrients, including cholesterol and fatty acids, to survive within macrophages. We found that intracellular growth of Mtb depends on host fatty acid catabolism: when host fatty acid β-oxidation (FAO) was blocked chemically with trimetazidine, a compound in clinical use, or genetically by deletion of the mitochondrial fatty acid transporter carnitine palmitoyltransferase 2 (CPT2), Mtb failed to grow in macrophages, and its growth was attenuated in mice. Mechanistic studies support a model in which inhibition of FAO generates mitochondrial reactive oxygen species, which enhance macrophage NADPH oxidase and xenophagy activity to better control Mtb infection. Thus, FAO inhibition promotes key antimicrobial functions of macrophages and overcomes immune evasion mechanisms of Mtb. IMPORTANCE Mycobacterium tuberculosis (Mtb) is the leading infectious disease killer worldwide. We discovered that intracellular Mtb fails to grow in macrophages in which fatty acid β-oxidation (FAO) is blocked. Macrophages treated with FAO inhibitors rapidly generate a burst of mitochondria-derived reactive oxygen species, which promotes NADPH oxidase recruitment and autophagy to limit the growth of Mtb. Furthermore, we demonstrate the ability of trimetazidine to reduce pathogen burden in mice infected with Mtb. These studies will add to the knowledge of how host metabolism modulates Mtb infection outcomes.

Download Full-text

Dimethyl Sulfoxide Protects Escherichia coli from Rapid Antimicrobial-Mediated Killing

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03003-15 ◽

2016 ◽

Vol 60 (8) ◽

pp. 5054-5058 ◽

Cited By ~ 12

Author(s):

Hongfei Mi ◽

Dai Wang ◽

Yunxin Xue ◽

Zhi Zhang ◽

Jianjun Niu ◽

...

Keyword(s):

Escherichia Coli ◽

Reactive Oxygen Species ◽

Cell Death ◽

Programmed Cell Death ◽

Dimethyl Sulfoxide ◽

Oxygen Species ◽

Content Type ◽

Antimicrobial Studies ◽

Ros Accumulation ◽

Short Time

ABSTRACTThe contribution of reactive oxygen species (ROS) to antimicrobial lethality was examined by treatingEscherichia coliwith dimethyl sulfoxide (DMSO), an antioxidant solvent frequently used in antimicrobial studies. DMSO inhibited killing by ampicillin, kanamycin, and two quinolones and had little effect on MICs. DMSO-mediated protection correlated with decreased ROS accumulation and provided evidence for ROS-mediated programmed cell death. These data support the contribution of ROS to antimicrobial lethality and suggest caution when using DMSO-dissolved antimicrobials for short-time killing assays.

Download Full-text

Targeting Mitochondrial Metabolism as a Strategy to Treat Senescence

Cells ◽

10.3390/cells10113003 ◽

2021 ◽

Vol 10 (11) ◽

pp. 3003

Author(s):

Yun Haeng Lee ◽

Ji Yun Park ◽

Haneur Lee ◽

Eun Seon Song ◽

Myeong Uk Kuk ◽

...

Keyword(s):

Energy Source ◽

Reactive Oxygen Species ◽

Oxidative Phosphorylation ◽

Reactive Oxygen ◽

Mitochondrial Metabolism ◽

Metabolic Reprogramming ◽

Oxygen Species ◽

Metabolic Alterations ◽

Age Related

Mitochondria are one of organelles that undergo significant changes associated with senescence. An increase in mitochondrial size is observed in senescent cells, and this increase is ascribed to the accumulation of dysfunctional mitochondria that generate excessive reactive oxygen species (ROS). Such dysfunctional mitochondria are prime targets for ROS-induced damage, which leads to the deterioration of oxidative phosphorylation and increased dependence on glycolysis as an energy source. Based on findings indicating that senescent cells exhibit mitochondrial metabolic alterations, a strategy to induce mitochondrial metabolic reprogramming has been proposed to treat aging and age-related diseases. In this review, we discuss senescence-related mitochondrial changes and consequent mitochondrial metabolic alterations. We assess the significance of mitochondrial metabolic reprogramming for senescence regulation and propose the appropriate control of mitochondrial metabolism to ameliorate senescence. Learning how to regulate mitochondrial metabolism will provide knowledge for the control of aging and age-related pathologies. Further research focusing on mitochondrial metabolic reprogramming will be an important guide for the development of anti-aging therapies, and will provide novel strategies for anti-aging interventions.

Download Full-text

Imidazoles Induce Reactive Oxygen Species in Mycobacterium tuberculosis Which Is Not Associated with Cell Death

ACS Omega ◽

10.1021/acsomega.6b00212 ◽

2017 ◽

Vol 2 (1) ◽

pp. 41-51 ◽

Cited By ~ 9

Author(s):

Heather A. Howell Wescott ◽

David M. Roberts ◽

Christian L. Allebach ◽

Rachel Kokoczka ◽

Tanya Parish

Keyword(s):

Reactive Oxygen Species ◽

Cell Death ◽

Mycobacterium Tuberculosis ◽

Reactive Oxygen ◽

Oxygen Species

Download Full-text

SrrAB Modulates Staphylococcus aureus Cell Death through Regulation ofcidABCTranscription

Journal of Bacteriology ◽

10.1128/jb.00954-15 ◽

2016 ◽

Vol 198 (7) ◽

pp. 1114-1122 ◽

Cited By ~ 15

Author(s):

Ian H. Windham ◽

Sujata S. Chaudhari ◽

Jeffrey L. Bose ◽

Vinai C. Thomas ◽

Kenneth W. Bayles

Keyword(s):

Reactive Oxygen Species ◽

Staphylococcus Aureus ◽

Cell Death ◽

Reactive Oxygen ◽

Extracellular Dna ◽

Death Process ◽

Oxygen Species ◽

Content Type ◽

Biofilm Development

ABSTRACTThe death and lysis of a subpopulation inStaphylococcus aureusbiofilm cells are thought to benefit the surviving population by releasing extracellular DNA, a critical component of the biofilm extracellular matrix. Although the means by whichS. aureuscontrols cell death and lysis is not understood, studies implicate the role of thecidABCandlrgABoperons in this process. Recently, disruption of thesrrABregulatory locus was found to cause increased cell death during biofilm development, likely as a result of the sensitivity of this mutant to hypoxic growth. In the current study, we extended these findings by demonstrating that cell death in the ΔsrrABmutant is dependent on expression of thecidABCoperon. The effect ofcidABCexpression resulted in the generation of increased reactive oxygen species (ROS) accumulation and was independent of acetate production. Interestingly, consistently with previous studies,cidC-encoded pyruvate oxidase was found to be important for the generation of acetic acid, which initiates the cell death process. However, these studies also revealed for the first time an important role of thecidBgene in cell death, as disruption ofcidBin the ΔsrrABmutant background decreased ROS generation and cell death in acidC-independent manner. ThecidBmutation also caused decreased sensitivity to hydrogen peroxide, which suggests a complex role for this system in ROS metabolism. Overall, the results of this study provide further insight into the function of thecidABCoperon in cell death and reveal its contribution to the oxidative stress response.IMPORTANCEThe manuscript focuses on cell death mechanisms inStaphylococcus aureusand provides important new insights into the genes involved in this ill-defined process. By exploring the cause of increased stationary-phase death in anS. aureusΔsrrABregulatory mutant, we found that the decreased viability of this mutant was a consequence of the overexpression of thecidABCoperon, previously shown to be a key mediator of cell death. These investigations highlight the role of thecidBgene in the death process and the accumulation of reactive oxygen species. Overall, the results of this study are the first to demonstrate a positive role for CidB in cell death and to provide an important paradigm for understanding this process in all bacteria.

Download Full-text

CD157 Confers Host Resistance to Mycobacterium tuberculosis via TLR2-CD157-PKCzeta-Induced Reactive Oxygen Species Production

mBio ◽

10.1128/mbio.01949-19 ◽

2019 ◽

Vol 10 (4) ◽

Cited By ~ 3

Author(s):

Qianting Yang ◽

Mingfeng Liao ◽

Wenfei Wang ◽

Mingxia Zhang ◽

Qi Chen ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Mycobacterium Tuberculosis ◽

Host Resistance ◽

Ros Production ◽

Oxygen Species ◽

Effective Strategy ◽

Content Type ◽

Protein Levels

ABSTRACT Recruitment of monocytes to the infection site is critical for host resistance against Mycobacterium tuberculosis. CD157 has a crucial role in neutrophil and monocyte transendothelial migration and adhesion, but its role in tuberculosis (TB) is unclear. Here, we show that both mRNA and protein levels of Cd157 are significantly increased during M. tuberculosis infection. Deficiency of Cd157 impaired host response to M. tuberculosis infection by increasing bacterial burden and inflammation in the lung in the murine TB model. In vitro experiments show that the bactericidal ability was compromised in Cd157 knockout (KO) macrophages, which was due to impaired M. tuberculosis-induced reactive oxygen species (ROS) production. We further reveal that CD157 interacts with TLR2 and PKCzeta and facilitates M. tuberculosis-induced ROS production in Cd157 KO macrophages, which resulted in enhanced M. tuberculosis killing. For the clinic aspect, we observe that the expression of CD157 decreases after effective anti-TB chemotherapy. CD157 is specifically increased in pleural fluid in tuberculous pleurisy patients compared to pneumonia and lung cancer patients. Interestingly, the levels of soluble CD157 (sCD157) correlate with human peripheral monocyte-derived macrophage bactericidal activity. Exogenous application of sCD157 could compensate for macrophage bactericidal ability and restore ROS production. In conclusion, we have identified a novel protective immune function of CD157 during M. tuberculosis infection via TLR2-dependent ROS production. Application of sCD157 might be an effective strategy for host-directed therapy against TB in those with insufficient CD157 production. IMPORTANCE Tuberculosis, a chronic bacterial disease caused by Mycobacterium tuberculosis, remains a major global health problem. CD157, a dual-function receptor and β-NAD+-metabolizing ectoenzyme, promotes cell polarization, regulates chemotaxis induced through the high-affinity fMLP receptor, and controls transendothelial migration. The role of CD157 in TB pathogenesis remains unknown. In this study, we find that both mRNA and protein levels of CD157 are significantly increased in TB. Deficiency of CD157 impaired host defense against M. tuberculosis infection both in vivo and in vitro, which is mediated by an interaction among CD157, TLR2, and PKCzeta. This interaction facilitates M. tuberculosis-induced macrophagic ROS production, which enhances macrophage bactericidal activity. Interestingly, the sCD157 level in plasma is reversibly associated with MDM M. tuberculosis killing activity. By uncovering the role of CD157 in pathogenesis of TB for the first time, our work demonstrated that application of soluble CD157 might be an effective strategy for host-directed therapy against TB.

Download Full-text

N-Acetylglucosamine-Induced Cell Death in Candida albicans and Its Implications for Adaptive Mechanisms of Nutrient Sensing in Yeasts

mBio ◽

10.1128/mbio.01376-15 ◽

2015 ◽

Vol 6 (5) ◽

Cited By ~ 17

Author(s):

Han Du ◽

Guobo Guan ◽

Xiaoling Li ◽

Megha Gulati ◽

Li Tao ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Cell Death ◽

Candida Albicans ◽

Fungal Pathogen ◽

Reactive Oxygen ◽

Nutrient Sensing ◽

Oxygen Species ◽

Gi Tract ◽

Content Type ◽

Cell Death Pathway

ABSTRACT Single-celled organisms have different strategies to sense and utilize nutrients in their ever-changing environments. The opportunistic fungal pathogen Candida albicans is a common member of the human microbiota, especially that of the gastrointestinal (GI) tract. An important question concerns how C. albicans gained a competitive advantage over other microbes to become a successful commensal and opportunistic pathogen. Here, we report that C. albicans uses N-acetylglucosamine (GlcNAc), an abundant carbon source present in the GI tract, as a signal for nutrient availability. When placed in water, C. albicans cells normally enter the G0 phase and remain viable for weeks. However, they quickly lose viability when cultured in water containing only GlcNAc. We term this phenomenon GlcNAc-induced cell death (GICD). GlcNAc triggers the upregulation of ribosomal biogenesis genes, alterations of mitochondrial metabolism, and the accumulation of reactive oxygen species (ROS), followed by rapid cell death via both apoptotic and necrotic mechanisms. Multiple pathways, including the conserved cyclic AMP (cAMP) signaling and GlcNAc catabolic pathways, are involved in GICD. GlcNAc acts as a signaling molecule to regulate multiple cellular programs in a coordinated manner and therefore maximizes the efficiency of nutrient use. This adaptive behavior allows C. albicans’ more efficient colonization of the gut. IMPORTANCE The ability to rapidly and appropriately respond to nutrients in the environment is crucial to free-living microorganisms. To maximize the use of available nutrients, microorganisms often use a limiting nutritional component as a signal to coordinate multiple biological processes. The human fungal pathogen Candida albicans uses N-acetylglucosamine (GlcNAc) as a signal for the availability of external nutrient resources. GlcNAc induces rapid cell death in C. albicans due to the constitutive activation of oxidative metabolism and accumulation of reactive oxygen species (ROS), and multiple pathways are involved in its regulation. This study sheds light on the mechanisms of niche specialization of pathogenic fungi and raises the possibility that this cell death pathway could be an unexplored therapeutic target.

Download Full-text

Mycobacterium tuberculosis Exploits Focal Adhesion Kinase to Induce Necrotic Cell Death and Inhibit Reactive Oxygen Species Production

Frontiers in Immunology ◽

10.3389/fimmu.2021.742370 ◽

2021 ◽

Vol 12 ◽

Author(s):

Afrakoma Afriyie-Asante ◽

Ankita Dabla ◽

Amy Dagenais ◽

Stefania Berton ◽

Robin Smyth ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Cell Death ◽

Mycobacterium Tuberculosis ◽

Focal Adhesion Kinase ◽

Focal Adhesion ◽

Reactive Oxygen ◽

Necrotic Cell Death ◽

Ros Production ◽

Oxygen Species ◽

Necrotic Cell

Tuberculosis is a deadly, contagious respiratory disease that is caused by the pathogenic bacterium Mycobacterium tuberculosis (Mtb). Mtb is adept at manipulating and evading host immunity by hijacking alveolar macrophages, the first line of defense against inhaled pathogens, by regulating the mode and timing of host cell death. It is established that Mtb infection actively blocks apoptosis and instead induces necrotic-like modes of cell death to promote disease progression. This survival strategy shields the bacteria from destruction by the immune system and antibiotics while allowing for the spread of bacteria at opportunistic times. As such, it is critical to understand how Mtb interacts with host macrophages to manipulate the mode of cell death. Herein, we demonstrate that Mtb infection triggers a time-dependent reduction in the expression of focal adhesion kinase (FAK) in human macrophages. Using pharmacological perturbations, we show that inhibition of FAK (FAKi) triggers an increase in a necrotic form of cell death during Mtb infection. In contrast, genetic overexpression of FAK (FAK+) completely blocked macrophage cell death during Mtb infection. Using specific inhibitors of necrotic cell death, we show that FAK-mediated cell death during Mtb infection occurs in a RIPK1-depedent, and to a lesser extent, RIPK3-MLKL-dependent mechanism. Consistent with these findings, FAKi results in uncontrolled replication of Mtb, whereas FAK+ reduces the intracellular survival of Mtb in macrophages. In addition, we demonstrate that enhanced control of intracellular Mtb replication by FAK+ macrophages is a result of increased production of antibacterial reactive oxygen species (ROS) as inhibitors of ROS production restored Mtb burden in FAK+ macrophages to same levels as in wild-type cells. Collectively, our data establishes FAK as an important host protective response during Mtb infection to block necrotic cell death and induce ROS production, which are required to restrict the survival of Mtb.

Download Full-text