Tag: ATP

Altered mitochondrial respiration in peripheral blood mononuclear cells of post-acute sequelae of SARS-CoV-2 infection

Abstract:

Peripheral blood mononuclear cells (PBMC) mitochondrial respiration was measured ex vivo from participants without a history of COVID (n = 19), with a history of COVID and full recovery (n = 20), and with PASC (n = 20). Mean mitochondrial basal respiration, ATP-linked respiration, maximal respiration, spare respiration capacity, ATP-linked respiration, and non-mitochondrial respiration were highest in COVID + PASC+ (p ≤ 0.04). Every unit increase in non-mitochondrial respiration, ATP-linked respiration, basal respiration, spare respiration capacity, and maximal respiration increased the predicted odds of PASC between 1 % and 6 %. Mitochondrial dysfunction in PBMCs may be contributing to the etiology of PASC.

Source: Dirajlal-Fargo S, Maison DP, Durieux JC, Andrukhiv A, Funderburg N, Ailstock K, Gerschenson M, Mccomsey GA. Altered mitochondrial respiration in peripheral blood mononuclear cells of post-acute sequelae of SARS-CoV-2 infection. Mitochondrion. 2024 Feb 8:101849. doi: 10.1016/j.mito.2024.101849. Epub ahead of print. PMID: 38341012. https://www.sciencedirect.com/science/article/pii/S1567724924000072 (Full text)

Metabolomic and immune alterations in long COVID patients with chronic fatigue syndrome

Introduction: A group of SARS-CoV-2 infected individuals present lingering symptoms, defined as long COVID (LC), that may last months or years post the onset of acute disease. A portion of LC patients have symptoms similar to myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), which results in a substantial reduction in their quality of life. A better understanding of the pathophysiology of LC, in particular, ME/CFS is urgently needed.

Methods: We identified and studied metabolites and soluble biomarkers in plasma from LC individuals mainly exhibiting ME/CFS compared to age-sex-matched recovered individuals (R) without LC, acute COVID-19 patients (A), and to SARS-CoV-2 unexposed healthy individuals (HC).

Results: Through these analyses, we identified alterations in several metabolomic pathways in LC vs other groups. Plasma metabolomics analysis showed that LC differed from the R and HC groups. Of note, the R group also exhibited a different metabolomic profile than HC. Moreover, we observed a significant elevation in the plasma pro-inflammatory biomarkers (e.g. IL-1α, IL-6, TNF-α, Flt-1, and sCD14) but the reduction in ATP in LC patients. Our results demonstrate that LC patients exhibit persistent metabolomic abnormalities 12 months after the acute COVID-19 disease. Of note, such metabolomic alterations can be observed in the R group 12 months after the acute disease. Hence, the metabolomic recovery period for infected individuals with SARS-CoV-2 might be long-lasting. In particular, we found a significant reduction in sarcosine and serine concentrations in LC patients, which was inversely correlated with depression, anxiety, and cognitive dysfunction scores.

Conclusion: Our study findings provide a comprehensive metabolomic knowledge base and other soluble biomarkers for a better understanding of the pathophysiology of LC and suggests sarcosine and serine supplementations might have potential therapeutic implications in LC patients. Finally, our study reveals that LC disproportionally affects females more than males, as evidenced by nearly 70% of our LC patients being female.

Source: Saito Suguru, Shahbaz Shima, Luo Xian, Osman Mohammed, Redmond Desiree, Cohen Tervaert Jan Willem, Li Liang, Elahi Shokrollah. Metabolomic and immune alterations in long COVID patients with chronic fatigue syndrome. Frontiers in Immunology, Vol 15, 2024. DOI=10.3389/fimmu.2024.1341843  https://www.frontiersin.org/articles/10.3389/fimmu.2024.1341843/full (Full text)

In vitro B cell experiments explore the role of CD24, CD38 and energy metabolism in ME/CFS

Abstract:

Disturbances of energy metabolism contribute to clinical manifestations of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Previously we found that B cells from ME/CFS patients have increased expression of CD24, a modulator of many cellular functions including those of cell stress.

The relative ability of B cells from ME/CFS patients and healthy controls (HC) to respond to rapid changes in energy demand were compared. CD24, the ectonucleotidases CD39, CD73, the NAD-degrading enzyme CD38 and mitochondrial mass (MM) were measured following cross-linking of the B cell receptor (BCR) and co-stimulation with either T cell dependent or Toll-like receptor-9 dependent agonists. Levels of metabolites consumed/produced were measured using 1H-NMR spectroscopy and analysed in relation to cell growth and immunophenotype.

Proliferating B cells from patients with ME/CFS showed lower mitochondrial mass and a significantly increased usage of essential amino acids compared those from HC, with a significantly delayed loss of CD24 and increased expression of CD38 following stimulation. Immunophenotype results suggested the triggering of a stress response in ME/CFS B cells associated with increased usage of additional substrates to maintain necessary ATP levels. Disturbances in energy metabolism in ME/CFS B cells were thus confirmed in a dynamic in vitro model, providing the basis for further mechanistic investigations.

Source: Christopher Armstrong, Fane F. Mensah, Maria Leandro, Venkat Reddy, Paul R. Gooley, Saul Berkovitz, Geraldine Cambridge. In vitro B cell experiments explore the role of CD24, CD38 and energy metabolism in ME/CFS. Front. Immunol. Sec. B Cell Biology, Volume 14 – 2023 | doi: 10.3389/fimmu.2023.1178882 https://www.frontiersin.org/articles/10.3389/fimmu.2023.1178882/abstract

Proteomic profiling demonstrates inflammatory and endotheliopathy signatures associated with impaired cardiopulmonary exercise hemodynamic profile in Post Acute Sequelae of SARS-CoV-2 infection (PASC) syndrome

Abstract:

Approximately 50% of patients who recover from the acute SARS-CoV-2 experience Post Acute Sequelae of SARS-CoV-2 infection (PASC) syndrome. The pathophysiological hallmark of PASC is characterized by impaired system oxygen extraction (EO2) on invasive cardiopulmonary exercise test (iCPET). However, the mechanistic insights into impaired EO2 remain unclear.

We studied 21 consecutive iCPET in PASC patients with unexplained exertional intolerance. PASC patients were dichotomized into mildly reduced (EO2peak-mild) and severely reduced (EO2peak-severe) EO2 groups according to the median peak EO2 value. Proteomic profiling was performed on mixed venous blood plasma obtained at peak exercise during iCPET.

PASC patients as a group exhibited depressed peak exercise aerobic capacity (peak VO2; 85 ± 18 vs. 131 ± 45% predicted; p = 0.0002) with normal systemic oxygen delivery, DO2 (37 ± 9 vs. 42 ± 15 mL/kg/min; p = 0.43) and reduced EO2 (0.4 ± 0.1 vs. 0.8 ± 0.1; p < 0.0001). PASC patients with EO2peak-mild exhibited greater DO2 compared to those with EO2peak-severe [42.9 (34.2-41.2) vs. 32.1 (26.8-38.0) mL/kg/min; p = 0.01]. The proteins with increased expression in the EO2peak-severe group were involved in inflammatory and fibrotic processes. In the EO2peak-mild group, proteins associated with oxidative phosphorylation and glycogen metabolism were elevated.

In PASC patients with impaired EO2, there exist a spectrum of PASC phenotype related to differential aberrant protein expression and cardio-pulmonary physiologic response. PASC patients with EO2peak-severe exhibit a maladaptive physiologic and proteomic signature consistent with persistent inflammatory state and endothelial dysfunction, while in the EO2peak-mild group, there is enhanced expression of proteins involved in oxidative phosphorylation-mediated ATP synthesis along with an enhanced cardiopulmonary physiological response.

Source: Singh I, Leitner BP, Wang Y, Zhang H, Joseph P, Lutchmansingh DD, Gulati M, Possick JD, Damsky W, Hwa J, Heerdt PM, Chun HJ. Proteomic profiling demonstrates inflammatory and endotheliopathy signatures associated with impaired cardiopulmonary exercise hemodynamic profile in Post Acute Sequelae of SARS-CoV-2 infection (PASC) syndrome. Pulm Circ. 2023 Apr 1;13(2):e12220. doi: 10.1002/pul2.12220. PMID: 37091121; PMCID: PMC10113513. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10113513/ (Full text)

Transcriptional reprogramming from innate immune functions to a pro-thrombotic signature by monocytes in COVID-19

Abstract:

Although alterations in myeloid cells have been observed in COVID-19, the specific underlying mechanisms are not completely understood. Here, we examine the function of classical CD14+ monocytes in patients with mild and moderate COVID-19 during the acute phase of infection and in healthy individuals.

Monocytes from COVID-19 patients display altered expression of cell surface receptors and a dysfunctional metabolic profile that distinguish them from healthy monocytes. Secondary pathogen sensing ex vivo leads to defects in pro-inflammatory cytokine and type-I IFN production in moderate COVID-19 cases, together with defects in glycolysis.

COVID-19 monocytes switch their gene expression profile from canonical innate immune to pro-thrombotic signatures and are functionally pro-thrombotic, both at baseline and following ex vivo stimulation with SARS-CoV-2. Transcriptionally, COVID-19 monocytes are characterized by enrichment of pathways involved in hemostasis, immunothrombosis, platelet aggregation and other accessory pathways to platelet activation and clot formation. These results identify a potential mechanism by which monocyte dysfunction may contribute to COVID-19 pathology.

Source: Maher AK, Burnham KL, Jones EM, Tan MMH, Saputil RC, Baillon L, Selck C, Giang N, Argüello R, Pillay C, Thorley E, Short CE, Quinlan R, Barclay WS, Cooper N, Taylor GP, Davenport EE, Dominguez-Villar M. Transcriptional reprogramming from innate immune functions to a pro-thrombotic signature by monocytes in COVID-19. Nat Commun. 2022 Dec 26;13(1):7947. doi: 10.1038/s41467-022-35638-y. PMID: 36572683; PMCID: PMC9791976. https://www.nature.com/articles/s41467-022-35638-y (Full text)

Bioenergetic and Proteomic Profiling of Immune Cells in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients: An Exploratory Study

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a heterogeneous, debilitating, and complex disease. Along with disabling fatigue, ME/CFS presents an array of other core symptoms, including autonomic nervous system (ANS) dysfunction, sustained inflammation, altered energy metabolism, and mitochondrial dysfunction. Here, we evaluated patients’ symptomatology and the mitochondrial metabolic parameters in peripheral blood mononuclear cells (PBMCs) and plasma from a clinically well-characterised cohort of six ME/CFS patients compared to age- and gender-matched controls.

We performed a comprehensive cellular assessment using bioenergetics (extracellular flux analysis) and protein profiles (quantitative mass spectrometry-based proteomics) together with self-reported symptom measures of fatigue, ANS dysfunction, and overall physical and mental well-being. This ME/CFS cohort presented with severe fatigue, which correlated with the severity of ANS dysfunction and overall physical well-being.

PBMCs from ME/CFS patients showed significantly lower mitochondrial coupling efficiency. They exhibited proteome alterations, including altered mitochondrial metabolism, centred on pyruvate dehydrogenase and coenzyme A metabolism, leading to a decreased capacity to provide adequate intracellular ATP levels. Overall, these results indicate that PBMCs from ME/CFS patients have a decreased ability to fulfill their cellular energy demands.

Source: Fernandez-Guerra P, Gonzalez-Ebsen AC, Boonen SE, Courraud J, Gregersen N, Mehlsen J, Palmfeldt J, Olsen RKJ, Brinth LS. Bioenergetic and Proteomic Profiling of Immune Cells in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients: An Exploratory Study. Biomolecules. 2021 Jun 29;11(7):961. doi: 10.3390/biom11070961. PMID: 34209852. https://pubmed.ncbi.nlm.nih.gov/34209852/

A SWATH-MS analysis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome peripheral blood mononuclear cell proteomes reveals mitochondrial dysfunction

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a serious and complex physical illness that affects all body systems with a multiplicity of symptoms, but key hallmarks of the disease are pervasive fatigue and ‘post-exertional malaise’, exacerbation after physical and/or mental activity of the intrinsic fatigue and other symptoms that can be highly debilitating and last from days to months. Although the disease can vary widely between individuals, common symptoms also include pain, cognitive deficits, sleep dysfunction, as well as immune, neurological and autonomic symptoms. Typically, it is a very isolating illness socially, carrying a stigma because of the lack of understanding of the cause and pathophysiology.

Methods: To gain insight into the pathophysiology of ME/CFS, we examined the proteomes of peripheral blood mononuclear cells (PBMCs) by SWATH-MS analysis in a small well-characterised group of patients and matched controls. A principal component analysis (PCA) was used to stratify groups based on protein abundance patterns, which clearly segregated the majority of the ME/CFS patients (9/11) from the controls. This majority subgroup of ME/CFS patients was then further compared to the control group.

Results: A total of 60 proteins in the ME/CFS patients were differentially expressed (P < 0.01, Log10 (Fold Change) > 0.2 and < -0.2). Comparison of the PCA selected subgroup of ME/CFS patients (9/11) with controls increased the number of proteins differentially expressed to 99. Of particular relevance to the core symptoms of fatigue and post-exertional malaise experienced in ME/CFS, a proportion of the identified proteins in the ME/CFS groups were involved in mitochondrial function, oxidative phosphorylation, electron transport chain complexes, and redox regulation. A significant number were also involved in previously implicated disturbances in ME/CFS, such as the immune inflammatory response, DNA methylation, apoptosis and proteasome activation.

Conclusions: The results from this study support a model of deficient ATP production in ME/CFS, compensated for by upregulation of immediate pathways upstream of Complex V that would suggest an elevation of oxidative stress. This study and others have found evidence of a distinct pathology in ME/CFS that holds promise for developing diagnostic biomarkers.

Source: Sweetman E, Kleffmann T, Edgar C, de Lange M, Vallings R, Tate W. A SWATH-MS analysis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome peripheral blood mononuclear cell proteomes reveals mitochondrial dysfunction. J Transl Med. 2020 Sep 24;18(1):365. doi: 10.1186/s12967-020-02533-3. PMID: 32972442. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-020-02533-3 (Full text)

Suggested pathology of systemic exertion intolerance disease: Impairment of the E3 subunit or crossover of swinging arms of the E2 subunit of the pyruvate dehydrogenase complex decreases regeneration of cofactor dihydrolipoic acid of the E2 subunit

Abstract:

Systemic Exertion Intolerance Disease (SEID) or myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) has an unknown aetiology, with no known treatment and a prevalence of approximately 22 million individuals (2%) in Western countries. Although strongly suspected, the role of lactate in pathology is unknown, nor has the nature of the two most central symptoms of the condition – post exertional malaise and fatigue. The proposed mechanism of action of pyruvate dehydrogenase complex (PDC) plays a central role in maintaining energy production with cofactors alpha-lipoic acid (LA) and its counterpart dihydrolipoic acid (DHLA), its regeneration suggested as the new rate limiting factor.

Decreased DHLA regeneration due to impairment of the E3 subunit or crossover of the swinging arms of the E2 subunit of PDC have been suggested as a cause of ME/CFS/SEID resulting in instantaneous fluctuations in lactate levels and instantaneous offset of the DHLA/LA ratio and defining the condition as an LA deficiency with chronic instantaneous hyperlactataemia with explicit stratification of symptoms. While instantaneous hyperlactataemia has been suggested to account for the PEM, the fatigue was explained by the downregulated throughput of pyruvate and consequently lower production of ATP with the residual enzymatic efficacy of the E3 subunit or crossover of the E2 as a proposed explanation of the fatigue severity. Functional diagnostics and visualization of instantaneous elevations of lactate and DHLA has been suggested.

Novel treatment strategies have been implicated to compensate for chronic PDC impairment and hyperlactataemia. This hypothesis potentially influences the current understanding and treatment methods for any type of hyperlactataemia, fatigue, ME/CFS/SEID, and conditions associated with PDC impairment.

Copyright © 2019. Published by Elsevier Ltd.

Source: Bohne VJB, Bohne Ø.Suggested pathology of systemic exertion intolerance disease: Impairment of the E3 subunit or crossover of swinging arms of the E2 subunit of the pyruvate dehydrogenase complex decreases regeneration of cofactor dihydrolipoic acid of the E2 subunit. Med Hypotheses. 2019 Sep;130:109260. doi: 10.1016/j.mehy.2019.109260. Epub 2019 Jun 14. https://www.ncbi.nlm.nih.gov/pubmed/31383326

Chronic fatigue and immune deficiency syndrome (CFIDS), cellular metabolism, and ionizing radiation: a review of contemporary scientific literature and suggested directions for future research

Abstract:

PURPOSE: To investigate biochemical pathways known to be involved in radiation response and in CFIDS to determine if there might be common underlying mechanisms leading to symptoms experienced by those accidentally or deliberately exposed to radiation and those suffering from CFIDS. If such a link was established to suggest testable hypotheses to investigate the mechanisms with the aim of identifying new therapeutic targets.

CONCLUSIONS: Evidence for involvement of the alpha-synuclein, cytochrome c oxidase, αB-crystallin, RNase L, and lactate dehydrogenase/STAT1 pathways is strong and suggests a common underlying mechanism involving mitochondrial dysfunction mediated by ROS and disruption of ATP production. The downstream effect of this is compromised energy production. Testable hypotheses are suggested to investigate the involvement of these pathways further.

Source: Rusin A, Seymour C, Mothersill C. Chronic fatigue and immune deficiency syndrome (CFIDS), cellular metabolism, and ionizing radiation: a review of contemporary scientific literature and suggested directions for future research. Int J Radiat Biol. 2018 Jan 10:1-17. doi: 10.1080/09553002.2018.1422871. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29297728 

Elevated Energy Production in Chronic Fatigue Syndrome Patients

Abstract:

Chronic Fatigue Syndrome (CFS) is a debilitating disease characterized by physical and mental exhaustion. The underlying pathogenesis is unknown, but impairments in certain mitochondrial functions have been found in some CFS patients. To thoroughly reveal mitochondrial deficiencies in CFS patients, here we examine the key aspects of mitochondrial function in blood cells from a paired CFS patient-control series. Surprisingly, we discover that in patients the ATP levels are higher and mitochondrial cristae are more condensed compared to their paired controls, while the mitochondrial crista length, mitochondrial size, shape, density, membrane potential, and enzymatic activities of the complexes in the electron transport chain remain intact. We further show that the increased ATP largely comes from non-mitochondrial sources. Our results indicate that the fatigue symptom in this cohort of patients is unlikely caused by lack of ATP and severe mitochondrial malfunction. On the contrary, it might be linked to a pathological mechanism by which more ATP is produced by non-mitochondrial sources.

 

Source: Lawson N, Hsieh CH, March D, Wang X. Elevated Energy Production in Chronic Fatigue Syndrome Patients. J Nat Sci. 2016;2(10). pii: e221. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5065105/ (Full article)