Cardioprotective Potential of Cymbopogon citratus Essential Oil against Isoproterenol-induced Cardiomyocyte Hypertrophy:Possible Involvement of NLRP3 Inflammasome and Oxidative Phosphorylation Complex Subunits

Objective:Cymbopogon citratus(DC.)Stapf is a medicinal and edible herb that is widely used for the treatment of gastric,nervous and hypertensive disorders.In this study,we investigated the cardioprotective effects and mechanisms of the essential oil,the main active ingredient of Cymbopogon citratus,on isoproterenol(ISO)-induced cardiomyocyte hypertrophy.Methods:The compositions of Cymbopogon citratus essential oil(CCEO)were determined by gas chromatography-mass spectrometry.Cardiomyocytes were pretreated with 16.9µg/L CCEO for 1 h followed by 10µmol/L ISO for 24 h.Cardiac hypertrophy-related indicators and NLRP3 inflammasome expression were evaluated.Subsequently,transcriptome sequencing(RNA-seq)and target verification were used to further explore the underlying mechanism.Results:Our results showed that the CCEO mainly included citronellal(45.66%),geraniol(23.32%),and citronellol(10.37%).CCEO inhibited ISO-induced increases in cell surface area and protein content,as well as the upregulation of fetal gene expression.Moreover,CCEO inhibited ISO-induced NLRP3 inflammasome expression,as evidenced by decreased lactate dehydrogenase content and downregulated mRNA levels of NLRP3,ASC,CASP1,GSDMD,and IL-1β,as well as reduced protein levels of NLRP3,ASC,pro-caspase-1,caspase-1(p20),GSDMD-FL,GSDMD-N,and pro-IL-1β.The RNA-seq results showed that CCEO inhibited the increase in the mRNA levels of 26 oxidative phosphorylation complex subunits in ISO-treated cardiomyocytes.Our further experiments confirmed that CCEO suppressed ISO-induced upregulation of mt-Nd1,Sdhd,mt-Cytb,Uqcrq,and mt-Atp6 but had no obvious effects on mt-Col expression.Conclusion:CCEO inhibits ISO-induced cardiomyocyte hypertrophy through the suppression of NLRP3 inflammasome expression and the regulation of several oxidative phosphorylation complex subunits.

Combined Oxidative Phosphorylation Deficiency-20-Exome as a Diagnostic Implement

Mitochondrial disorders are phenotypically varied, with serious clinical repercussions. Among them, there is the deficiency of combined oxidative phosphorylation of type 20, which occurs due to a defect in the VARS2 gene. This article presents a case of a 2-year-old female with progressive myoclonic epilepsy and psychomotor regression, with refractoriness to multiple anticonvulsants. The diagnosis was only made after the examination was carried out. Therefore, this article highlights the aspects of this rare disease and the importance of the exome for the diagnosis of rare conditions.

Control mechanisms in mitochondrial oxidative phosphorylation

Distribution and activity of mitochondda are key factors in neuronal development, synaptic plasticity and axogenesis. The majority of energy sources, necessary for cellular functions, originate from oxidative phosphorylation located in the inner mitochondrial membrane. The adenosine-5＇- triphosphate production is regulated by many control mechanism-firstly by oxygen, substrate level, adenosine-5＇-diphosphate level, mitochondrial membrane potential, and rate of coupling and proton leak. Recently, these mechanisms have been implemented by ＂second control mechanisms,＂ such as reversible phosphorylation of the tricarboxylic acid cycle enzymes and electron transport chain complexes, aUosteric inhibition of cytochrome c oxidase, thyroid hormones, effects of fatty acids and uncoupling proteins. Impaired function of mitochondria is implicated in many diseases ranging from mitochondrial myopathies to bipolar disorder and schizophrenia. Mitochondrial dysfunctions are usually related to the ability of mitochondria to generate adenosine-5＇-triphosphate in response to energy demands. Large amounts of reactive oxygen species are released by defective mitochondria similarly, decline of antioxidative enzyme activities （e.g. in the elderly） enhances reactive oxygen species production. We reviewed data concerning neuroplasticity, physiology, and control of mitochondrial oxidative phosphorylation and reactive oxygen species production.

Lack of transcriptional coordination between mitochondrial and nuclear oxidative phosphorylation genes in the presence of two divergent mitochondrial genomes

In most eukaryotes,oxidative phosphorylation(OXPHOS)is the main energy production process and it involves both mitochondrial and nuclear genomes.The close interaction between the two genomes is critical for the coordinated function of the OXPHOS process.Some bivalves show doubly uniparental inheritance(DUI)of mitochondria,where two highly divergent mitochondrial genomes,one inherited through eggs(F-type)and the other through sperm(M-type),coexist in the same individual.However,it remains a puzzle how nuclear OXPHOS genes coordinate with two divergent mitochondrial genomes in DUI species.In this study,we compared transcription,polymorphism,and synonymous codon usage in the mitochondrial and nuclear OXPHOS genes of the DUI species Ruditapes philippinarum using sex-and tissue-specific transcriptomes.Mitochondrial and nuclear OXPHOS genes showed different transcription profiles.Strong co-transcription signal was observed within mitochondrial(separate for F-and M-type)and within nuclear OXPHOS genes but the signal was weak or absent between mitochondrial and nuclear OXPHOS genes,suggesting that the coordination between mitochondrial and nuclear OXPHOS subunits is not achieved transcriptionally.McDonald-Kreitman and frequency-spectrum based tests indicated that M-type OXPHOS genes deviated significantly from neutrality,and that F-type and M-type OXPHOS genes undergo different selection patterns.Codon usage analysis revealed that mutation bias and translational selection were the major factors affecting the codon usage bias in different OXPHOS genes,nevertheless,translational selection in mitochondrial OXPHOS genes appears to be less efficient than nuclear OXPHOS genes.Therefore,we speculate that the coordination between OXPHOS genes may involve post-transcriptional/translational regulation.

Effects of Chinese herbal monomers on oxidative phosphorylation and membrane potential in cerebral mitochondria isolated from hypoxia-exposed rats in vitro

Mitochondrial dysfunction is the key pathogenic mechanism of cerebral injury induced by high-altitude hypoxia. Some Chinese herbal monomers may exert anti-hypoxic effects through enhancing the efficiency of oxidative phosphorylation, in this study, effects of 10 kinds of Chinese herbal monomers on mitochondrial respiration and membrane potential of cerebral mitochondria isolated from hypoxia-exposed rats in vitro were investigated to screen anti-hypoxic drugs. Rats were exposed to a low-pressure environment of 405.35 mm Hg （54.04 kPa） for 3 days to establish high-altitude hypoxic models. Cerebral mitochondria were isolated and treated with different concentrations of Chinese herbal monomers （sinomenine, silymarin, glycyrrhizic acid, baicalin, quercetin, ginkgolide B, saffron, pipedne, ginsenoside Rgl and oxymatrine） for 5 minutes in vitro. Mitochondrial oxygen consumption and membrane potential were measured using a Clark oxygen electrode and the rhodamine 123 fluorescence analysis method, respectively. Hypoxic exposure significantly decreased the state 3 respiratory rate, respiratory control rate and mitochondrial membrane potential, and significantly increased the state 4 respiratory rate. Treatment with saffron ginsenoside Rgl and oxymatrine increased the respiratory control rate in cerebral mitochondria isolated from hypoxia-exposed rats in dose-dependent manners in vitro, while ginsenoside Rgl, piperine and oxymatrine significantly increased the mitochondrial membrane potential in cerebral mitochondria from hypoxia-exposed rats. The Chinese herbal monomers saffron, ginsenoside Rgl piperine and oxymatrine could thus improve cerebral mitochondrial disorders in oxidative phosphorylation induced by hypobaric hypoxia exposure in vitro.

Single-cell transcriptomic analysis reveals transcript enrichment in oxidative phosphorylation,fluid sheer stress,and inflammatory pathways in obesity-related glomerulopathy

Obesity-related glomerulopathy(ORG)is an independent risk factor for chronic kid-ney disease and even progression to end-stage renal disease.Efforts have been undertaken to elucidate the mechanisms underlying the development of ORG and substantial advances have been made in the treatment of ORG,but relatively little is known about cell-specific changes in gene expression.To define the transcriptomic landscape at single-cell resolution,we analyzed kidney samples from four patients with ORG and three obese control subjects without kidney disease using single-cell RNA sequencing.We report for the first time that immune cells,including T cells and B cells,are decreased in ORG patients.Further analysis indicated that SPP1 was significantly up-regulated in T cells and B cells.This gene is related to inflammation and cell proliferation.Analysis of differential gene expression in glomerular cells(endothelial cells,mesangial cells,and podocytes)showed that these cell types were mainly enriched in genes related to oxidative phosphorylation,cell adhesion,thermogenesis,and inflammatory pathways(PI3K-Akt signaling,MAPK signaling).Furthermore,we found that the podocytes of ORG patients were enriched in genes related to the fluid shear stress pathway.Moreover,an evaluation of cell-cell communications revealed that there were interactions between glomerular parietal epithelial cells and other cells in ORG patients,with major interactions between parietal epithelial cells and podocytes.Altogether,our identification of molecular events,cell types,and differentially expressed genes may facilitate the development of new preventive or therapeutic approaches for ORG.

THE EFFECTS OF CYTOCHALASIN B ON THE SWELLING, CONTRACTION AND OXIDATIVE PHOSPHORYLATION IN ISOLATED MUNG BEAN MITOCHONDRIA

Cytochalasin B(CB)was a depolymeriziner agent of F-aetin.Therefore a lot of plant cell motilities related to action,such as cytoplasmic streaming,pollen

Androgen receptor signaling-mitochondrial DNA-oxidative phosphorylation:A critical triangle in early prostate cancer

Mitochondria are more than just the cellular powerhouse.They also play key roles in vital functions such as apoptosis,metabolism regulation,and other intracellular interactions.The mitochondrial DNA(mtDNA)encodes for 12 subunits of the oxidative phosphorylation(OXPHOS)system.Depletion of mtDNA in androgen-dependent prostate cancer(PCa)cell lines renders them androgen-independent and more aggressive.Paradoxically,pharmaceutical inhibition of OXPHOS is lethal for subsets of PCa cells,whereas others become dependent on androgen receptor(AR)signaling for survival.Given that the AR-mitochondria interaction is critical for early PCa,it is crucial to understand the details of this interaction.Technical hurdles have made mitochondria traditionally difficult to study,with many techniques used for isolation masking the properties of given individual mitochondria.Although the isolation of mitochondria enables us to study OXPHOS,we miss the context in which mitochondria interact with the rest of the cell.Both AR signaling and mtDNA affect apoptosis,metabolism regulation,cellular calcium storage and homeostasis,intracellular calcium signaling,and redox homeostasis.In this review,we will attempt to understand how the crosstalk between AR-mtDNA-OXPHOS is responsible for"life or death"decisions inside the cells.Our aim is to point toward potential vulnerabilities that can lead to the discovery of novel therapeutic targets.

Metabolic reprogramming of the inflammatory response in the nervous system:the crossover between inflammation and metabolism

Metabolism is a fundamental process by which biochemicals are broken down to produce energy(catabolism) or used to build macromolecules(anabolism). Metabolism has received renewed attention as a mechanism that generates molecules that modulate multiple cellular responses. This was first identified in cancer cells as the Warburg effect, but it is also present in immunocompetent cells. Studies have revealed a bidirectional influence of cellular metabolism and immune cell function, highlighting the significance of metabolic reprogramming in immune cell activation and effector functions. Metabolic processes such as glycolysis, oxidative phosphorylation, and fatty acid oxidation have been shown to undergo dynamic changes during immune cell response, facilitating the energetic and biosynthetic demands. This review aims to provide a better understanding of the metabolic reprogramming that occurs in different immune cells upon activation, with a special focus on central nervous system disorders. Understanding the metabolic changes of the immune response not only provides insights into the fundamental mechanisms that regulate immune cell function but also opens new approaches for therapeutic strategies aimed at manipulating the immune system.

Metabolic reprogramming: a new option for the treatment of spinal cord injury

Spinal cord injuries impose a notably economic burden on society,mainly because of the severe after-effects they cause.Despite the ongoing development of various therapies for spinal cord injuries,their effectiveness remains unsatisfactory.However,a deeper understanding of metabolism has opened up a new therapeutic opportunity in the form of metabolic reprogramming.In this review,we explore the metabolic changes that occur during spinal cord injuries,their consequences,and the therapeutic tools available for metabolic reprogramming.Normal spinal cord metabolism is characterized by independent cellular metabolism and intercellular metabolic coupling.However,spinal cord injury results in metabolic disorders that include disturbances in glucose metabolism,lipid metabolism,and mitochondrial dysfunction.These metabolic disturbances lead to corresponding pathological changes,including the failure of axonal regeneration,the accumulation of scarring,and the activation of microglia.To rescue spinal cord injury at the metabolic level,potential metabolic reprogramming approaches have emerged,including replenishing metabolic substrates,reconstituting metabolic couplings,and targeting mitochondrial therapies to alter cell fate.The available evidence suggests that metabolic reprogramming holds great promise as a next-generation approach for the treatment of spinal cord injury.To further advance the metabolic treatment of the spinal cord injury,future efforts should focus on a deeper understanding of neurometabolism,the development of more advanced metabolomics technologies,and the design of highly effective metabolic interventions.

In vivo measurement of NADH fluorescence lifetime in skeletal muscle via -ber-coupled time-correlated single photon counting

Nicotinamide adenine dinucleotide(NADH)is a cofactor that serves to shuttle electrons during metabolic processes such as glycolysis,the tricarboxylic acid cycle,and oxidative phosphorylation(OXPHOS).NADH is autofluorescent,and itsfluorescence lifetime can be used to infer metabolic dynamics in living cells.Fiber-coupled time-correlated single photon counting(TCSPC)equipped with an implantable needle probe can be used to measure NADH lifetime in vivo,enabling investigation of changing metabolic demand during muscle contraction or tissue regeneration.This study illustrates a proof of concept for point-based,minimally-invasive NADHfluorescence lifetime measurement in vivo.Volumetric muscle loss(VML)injuries were created in the left tibialis anterior(TA)muscle of male Sprague Dawley rats.NADH lifetime measurements were collected before,during,and after a 30 s tetanic contraction in the injured and uninjured TA muscles,which was subsequently-t to a biexponential decay model to yield a metric of NADH utilization(cytoplasmic vs protein-bound NADH,the A11/A22 ratio).On average,this ratio was higher during and after contraction in uninjured muscle compared to muscle at rest,suggesting higher levels of free NADH in contracting and recovering muscle,indicating increased rates of glycolysis.In injured muscle,this ratio was higher than uninjured muscle overall but decreased over time,which is consistent with current knowledge of inflammatory response to injury,suggesting tissue regeneration has occurred.These data suggest that-ber-coupled TCSPC has the potential to measure changes in NADH binding in vivo in a minimally invasive manner that requires further investigation.

Metformin-associated lactic acidosis:A mini review of pathophysiology,diagnosis and management in critically ill patients

Metformin is a common diabetes drug that may reduce lactate clearance by inhibiting mitochondrial oxidative phosphorylation,leading to metforminassociated lactic acidosis(MALA).As diabetes mellitus is a common chronic metabolic condition found in critically ill patients,pre-existing metformin use can often be found in critically ill patients admitted to the intensive care unit or the high dependency unit.The aim of this narrative mini review is therefore to update clinicians about MALA,and to provide a practical approach to its diagnosis and treatment.MALA in critically ill patients may be suspected in a patient who has received metformin and who has a high anion gap metabolic acidosis,and confirmed when lactate exceeds 5 mmol/L.Risk factors include those that reduce renal elimination of metformin(renal impairment from any cause,histamine-2 receptor antagonists,ribociclib)and excessive alcohol consumption(as ethanol oxidation consumes nicotinamide adenine dinucleotides that are also required for lactate metabolism).Treatment of MALA involves immediate cessation of metformin,supportive management,treating other concurrent causes of lactic acidosis like sepsis,and treating any coexisting diabetic ketoacidosis.Severe MALA requires extracorporeal removal of metformin with either intermittent hemodialysis or continuous kidney replacement therapy.The optimal time to restart metformin has not been well-studied.It is nonetheless reasonable to first ensure that lactic acidosis has resolved,and then recheck the kidney function post-recovery from critical illness,ensuring that the estimated glomerular filtration rate is 30 mL/min/1.73 m^(2) or better before restarting metformin.

Effects of Osmoconditioning on Mitochondrial Respiration and Phosphorylation in Soybean Seeds

Cotyledon mitochondrion respiration and oxidative phosphorylation activity were studied in two groups of soybean seeds. One group was primed with polyethylene glycol (PEG) for different periods of time, and the other was unprimed (control), and both were then exposed to imbibition at low temperatures before their germination. The results indicated that when L-Malate (L-Mal) and á-Ketoglutarate (α-Kg) were used as substrates, the ADP-stimulated mitochondria respiration rates of control seeds were mark- edly higher than state Ⅲ respiration rates of primed seeds. However, the osmoconditioning pretreatment significantly enhanced the oxidative phosphorylation activity of cotyledon mitochondrion in 12 h. The oxidative phosphorylation activity of the mitochondrion of primed seeds was normal and the ADP/O value was consistent with the theoretical one. When reduced nicotinamide adenine dinu- cleotide (NADH) was used as the substrate, the mitochondria of control seeds still had oxidative phosphorylation activity, while ADP/O value was obviously lower than that of mitochondria of primed seeds. When Succinate (Succ) was used as the substrate, the oxidative phosphorylation activity of the primed seeds was normal after priming for 24 h. When different substrates were used, the emerging order of the oxidative phosphorylation activity of the primed seeds was NADH, α-Kg, Succ and in the last place L-Mal. The mechanism of soybean imbibitionl chilling injury and protective effect of PEG priming were discussed.

Endothelial cell metabolism in sepsis

BACKGROUND:Endothelial dysfunction in sepsis is a pathophysiological feature of septic organ failure.Endothelial cells(ECs)exhibit specific metabolic traits and release metabolites to adapt to the septic state in the blood to maintain vascular homeostasis.METHODS:Web of Science and PubMed were searched from inception to October 1,2022.The search was limited to the English language only.Two reviewers independently identified studies related to EC metabolism in sepsis.The exclusion criteria were duplicate articles according to multiple search criteria.RESULTS:Sixty articles were included,and most of them were cell and animal studies.These studies reported the role of glycolysis,oxidative phosphorylation,fatty acid metabolism,and amino acid metabolism in EC homeostasis.including glycolysis,oxidative phosphorylation,fatty acid metabolism and amino acid metabolism.However,dysregulation of EC metabolism can contribute to sepsis progression.CONCLUSION:There are few clinical studies on EC metabolism in sepsis.Related research mainly focuses on basic research,but some scientific problems have also been clarified.Therefore,this review may provide an overall comprehension and novel aspects of EC metabolism in sepsis.

Crosslink between mutations in mitochondrial genes and brain disorders:implications for mitochondrial-targeted therapeutic interventions

At the present,association of mitochondrial dysfunction and progression of neurological disorders has gained significant attention.Defects in mitochondrial network dynamics,point mutations,deletions,and interaction of pathogenomic proteins with mitochondria are some of the possible underlying mechanisms involved in these neurological disorders.Mitochondrial genetics,defects in mitochondrial oxidative phosphorylation machinery,and reactive oxygen species production might share common crosstalk in the progression of these neurological disorders.It is of significant interests to explore and develop therapeutic strategies aimed at correcting mitochondrial abnormalities.This review provided insights on mitochondrial dysfunction/mutations involved in the progression of Alzheimer’s disease,Huntington’s disease,and epilepsy with a special focus on Parkinson’s disease pathology.Along with the deleterious effects of mitochondrial mutations in aforesaid neurological disorders,this paper unraveled the available therapeutic strategy,specifically aiming to improve mitochondrial dysfunction,drugs targeting mitochondrial proteins,gene therapies aimed at correcting mutant mtDNA,peptide-based approaches,and lipophilic cations.

Sepsis-induced mitochondrial dysfunction:A narrative review

Sepsis represents a deranged and exaggerated systemic inflammatory response to infection and is associated with vascular and metabolic abnormalities that trigger systemic organic dysfunction.Mitochondrial function has been shown to be severely impaired during the early phase of critical illness,with a reduction in biogenesis,increased generation of reactive oxygen species and a decrease in adenosine triphosphate synthesis of up to 50%.Mitochondrial dysfunction can be assessed using mitochondrial DNA concentration and respirometry assays,particularly in peripheral mononuclear cells.Isolation of monocytes and lymphocytes seems to be the most promising strategy for measuring mitochondrial activity in clinical settings because of the ease of collection,sample processing,and clinical relevance of the association between metabolic alterations and deficient immune responses in mononuclear cells.Studies have reported alterations in these variables in patients with sepsis compared with healthy controls and non-septic patients.However,few studies have explored the association between mitochondrial dysfunction in immune mononuclear cells and unfavorable clinical outcomes.An improvement in mitochondrial parameters in sepsis could theoretically serve as a biomarker of clinical recovery and response to oxygen and vasopressor therapies as well as reveal unexplored pathophysiological mechanistic targets.These features highlight the need for further studies on mitochondrial metabolism in immune cells as a feasible tool to evaluate patients in intensive care settings.The evaluation of mitochondrial metabolism is a promising tool for the evaluation and management of critically ill patients,especially those with sepsis.In this article,we explore the pathophysiological aspects,main methods of measurement,and the main studies in this field.

Mitochondria in Huntington’s disease:implications in pathogenesis and mitochondrial-targeted therapeutic strategies

Huntington’s disease is a genetic disease caused by expanded CAG repeats on exon 1 of the huntingtin gene located on chromosome 4.Compelling evidence implicates impaired mitochondrial energetics,altered mitochondrial biogenesis and quality control,disturbed mitochondrial trafficking,oxidative stress and mitochondrial calcium dyshomeostasis in the pathogenesis of the disorder.Unfortunately,conventional mitochondrial-targeted molecules,such as cysteamine,creatine,coenzyme Q10,or triheptanoin,yielded negative or inconclusive results.However,future therapeutic strategies,aiming to restore mitochondrial biogenesis,improving the fission/fusion balance,and improving mitochondrial trafficking,could prove useful tools in improving the phenotype of Huntington’s disease and,used in combination with genome-editing methods,could lead to a cure for the disease.

Bioenergetic alteration in gastrointestinal cancers:The good,the bad and the ugly

Cancer cells exhibit metabolic reprogramming and bioenergetic alteration,utilizing glucose fermentation for energy production,known as the Warburg effect.However,there are a lack of comprehensive reviews summarizing the metabolic reprogramming,bioenergetic alteration,and their oncogenetic links in gastrointestinal(GI)cancers.Furthermore,the efficacy and treatment potential of emerging anticancer drugs targeting these alterations in GI cancers require further evaluation.This review highlights the interplay between aerobic glycolysis,the tricarboxylic acid(TCA)cycle,and oxidative phosphorylation(OXPHOS)in cancer cells,as well as hypotheses on the molecular mechanisms that trigger this alteration.The role of hypoxia-inducible transcription factors,tumor suppressors,and the oncogenetic link between hypoxia-related enzymes,bioenergetic changes,and GI cancer are also discussed.This review emphasizes the potential of targeting bioenergetic regulators for anti-cancer therapy,particularly for GI cancers.Emphasizing the potential of targeting bioenergetic regulators for GI cancer therapy,the review categorizes these regulators into aerobic glycolysis/lactate biosynthesis/transportation and TCA cycle/coupled OXPHOS.We also detail various anti-cancer drugs and strategies that have produced pre-clinical and/or clinical evidence in treating GI cancers,as well as the challenges posed by these drugs.Here we highlight that understanding dysregulated cancer cell bioenergetics is critical for effective treatments,although the diverse metabolic patterns present challenges for targeted therapies.Further research is needed to comprehend the specific mechanisms of inhibiting bioenergetic enzymes,address side effects,and leverage high-throughput multi-omics and spatial omics to gain insights into cancer cell heterogeneity for targeted bioenergetic therapies.

Platelets Play an Integral Role in Body Heat Production and Maintenance: A Newly Proposed Function

In platelets, most of the ADP is stored in dense granules and released into extracellular space through exocytosis as a signaling molecule upon platelet activation. Glycolysis and the TCA cycle consume considerable amounts of ADP;however, limiting quantities of available ADP to make ATP through OXPHOS result in failure of ATP production and release of energy as heat into the surroundings. Thus, body heat may be a potential product of circulating platelets. Furthermore, the incomplete OXPHOS process causes the production of ROS that leads to earlier platelet death resulting in shorter life span. In the future, this new function may have a wide variety of clinical applications.

Restoration of Mitochondrial Structure and Function within Helicobacter pylori VacA Intoxicated Cells

The Helicobacter pylori vacuolating cytotoxin (VacA) is an intracellular, mitochondrial-targeting exotoxin that rapidly causes mitochondrial dysfunction and fragmentation. Although VacA targeting of mitochondria has been reported to alter overall cellular metabolism, there is little known about the consequences of extended exposure to the toxin. Here, we describe studies to address this gap in knowledge, which have revealed that mitochondrial dysfunction and fragmentation are followed by a time-dependent recovery of mitochondrial structure, mitochondrial transmembrane potential, and cellular ATP levels. Cells exposed to VacA also initially demonstrated a reduction in oxidative phosphorylation, as well as increase in compensatory aerobic glycolysis. These metabolic alterations were reversed in cells with limited toxin exposure, congruent with the recovery of mitochondrial transmembrane potential and the absence of cytochrome c release from the mitochondria. Taken together, these results are consistent with a model that mitochondrial structure and function are restored in VacA-intoxicated cells.