Tag: cellular metabolism

SARS-CoV-2 Mitochondrial Metabolic and Epigenomic Reprogramming in COVID-19

Abstract:

To determine the effects of SARS-CoV-2 infection on cellular metabolism, we conducted an exhaustive survey of the cellular metabolic pathways modulated by SARS-CoV-2 infection and confirmed their importance for SARS-CoV-2 propagation by cataloging the effects of specific pathway inhibitors. This revealed that SARS-CoV-2 strongly inhibits mitochondrial oxidative phosphorylation (OXPHOS) resulting in increased mitochondrial reactive oxygen species (mROS) production.

The elevated mROS stabilizes HIF-1α which redirects carbon molecules from mitochondrial oxidation through glycolysis and the pentose phosphate pathway (PPP) to provide substrates for viral biogenesis. mROS also induces the release of mitochondrial DNA (mtDNA) which activates innate immunity. The restructuring of cellular energy metabolism is mediated in part by SARS-CoV-2 Orf8 and Orf10 whose expression restructures nuclear DNA (nDNA) and mtDNA OXPHOS gene expression.

These viral proteins likely alter the epigenome, either by directly altering histone modifications or by modulating mitochondrial metabolite substrates of epigenome modification enzymes, potentially silencing OXPHOS gene expression and contributing to long-COVID.

Source: Guarnieri JW, Haltom JA, Albrecht YES, Lie T, Olali AZ, Widjaja GA, Ranshing SS, Angelin A, Murdock D, Wallace DC. SARS-CoV-2 Mitochondrial Metabolic and Epigenomic Reprogramming in COVID-19. Pharmacol Res. 2024 Apr 11:107170. doi: 10.1016/j.phrs.2024.107170. Epub ahead of print. PMID: 38614374. https://www.sciencedirect.com/science/article/pii/S1043661824001142 (Full text)

From Cell to Symptoms: The Role of SARS-CoV-2 Cytopathic Effects in the Pathogenesis of COVID-19 and Long COVID

Abstract:

Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection triggers various events from molecular to tissue level, which in turn is given by the intrinsic characteristics of each patient. Given the molecular diversity characteristic of each cellular phenotype, the possible cytopathic, tissue and clinical effects are difficult to predict, which determines the heterogeneity of COVID-19 symptoms.
The purpose of this article is to provide a comprehensive review of the cytopathic effects of SARS-CoV-2 on various cell types, focusing on the development of COVID-19, which in turn may lead, in some patients, to a persistence of symptoms after recovery from the disease, a condition known as long COVID. We describe the molecular mechanisms underlying virus-host interactions, including alterations in protein expression, intracellular signaling pathways, and immune responses.
In particular, the article highlights the potential impact of these cytopathies on cellular function and clinical outcomes, such as immune dysregulation, neuropsychiatric disorders, and organ damage. The article concludes by discussing future directions for research and implications for the management and treatment of COVID-19 and long COVID.
Source: Gonzalez-Garcia P, Fiorillo Moreno O, Zarate Peñata E, Calderon-Villalba A, Pacheco Lugo L, Acosta Hoyos A, Villarreal Camacho JL, Navarro Quiroz R, Pacheco Londoño L, Aroca Martinez G, Moares N, Gabucio A, Fernandez-Ponce C, Garcia-Cozar F, Navarro Quiroz E. From Cell to Symptoms: The Role of SARS-CoV-2 Cytopathic Effects in the Pathogenesis of COVID-19 and Long COVID. International Journal of Molecular Sciences. 2023; 24(9):8290. https://doi.org/10.3390/ijms24098290 https://www.mdpi.com/1422-0067/24/9/8290 (Full text)

ME/CFS may be linked to failure in energy supply to the cells

By Elise Kjørstad

Researchers at the University of Bergen and Haukeland University Hospital were part of a research team for a new study that found differences in blood samples between ME/CFS patients and healthy people.

Patients with myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS, had different levels of some substances that affect energy metabolism in the cells.

“What we think might be an explanation is that restricted blood flow during activity means the cells are receiving too little oxygen, and this leaves metabolic traces over time,” says Karl Johan Tronstad.

In the new study, the researchers performed an analysis of metabolites and other substances in blood samples from ME/CFS patients. Metabolites are metabolic products that are created when the cells convert different substances in the body.

The researchers analysed blood samples from 83 individuals with ME/CFS and 35 healthy controls.

The researchers measured about 1700 substances in the blood samples they took.

In the ME/CFS patients, they found an altered level of over 300 substances. Many of them involved the conversion of amino acids, which build up proteins, and lipids (fats).

Read the rest of this article HERE.

 

 

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 

Cellular bioenergetics is impaired in patients with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a highly debilitating disease of unknown aetiology. Abnormalities in bioenergetic function have been cited as one possible cause for CFS. Preliminary studies were performed to investigate cellular bioenergetic abnormalities in CFS patients.

A series of assays were conducted using peripheral blood mononuclear cells (PBMCs) from CFS patients and healthy controls. These experiments investigated cellular patterns in oxidative phosphorylation (OXPHOS) and glycolysis. Results showed consistently lower measures of OXPHOS parameters in PBMCs taken from CFS patients compared with healthy controls. Seven key parameters of OXPHOS were calculated: basal respiration, ATP production, proton leak, maximal respiration, reserve capacity, non-mitochondrial respiration, and coupling efficiency.

While many of the parameters differed between the CFS and control cohorts, maximal respiration was determined to be the key parameter in mitochondrial function to differ between CFS and control PBMCs due to the consistency of its impairment in CFS patients found throughout the study (p≤0.003). The lower maximal respiration in CFS PBMCs suggests that when the cells experience physiological stress they are less able to elevate their respiration rate to compensate for the increase in stress and are unable to fulfil cellular energy demands. The metabolic differences discovered highlight the inability of CFS patient PBMCs to fulfil cellular energetic demands both under basal conditions and when mitochondria are stressed during periods of high metabolic demand.

Source: Cara Tomas, Audrey Brown, Victoria Strassheim, Joanna Elson, Julia Newton, Philip Manning. Cellular bioenergetics is impaired in patients with chronic fatigue syndrome. PLoS One. 2017 Oct 24;12(10):e0186802. doi: 10.1371/journal.pone.0186802. eCollection 2017. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186802 (Full article)

Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles

Abstract:

Chronic fatigue syndrome (CFS) is a persistent and unexplained pathological state characterized by exertional and severely debilitating fatigue, with/without infectious or neuropsychiatric symptoms, lasting at least 6 consecutive months. Its pathogenesis remains incompletely understood.

Here, we performed comprehensive metabolomic analyses of 133 plasma samples obtained from CFS patients and healthy controls to establish an objective diagnosis of CFS.

CFS patients exhibited significant differences in intermediate metabolite concentrations in the tricarboxylic acid (TCA) and urea cycles. The combination of ornithine/citrulline and pyruvate/isocitrate ratios discriminated CFS patients from healthy controls, yielding area under the receiver operating characteristic curve values of 0.801 (95% confidential interval [CI]: 0.711-0.890, P < 0.0001) and 0.750 (95% CI: 0.584-0.916, P = 0.0069) for training (n = 93) and validation (n = 40) datasets, respectively.

These findings provide compelling evidence that a clinical diagnostic tool could be developed for CFS based on the ratios of metabolites in plasma.

 

Source: Yamano E, Sugimoto M, Hirayama A, Kume S, Yamato M, Jin G, Tajima S, Goda N, Iwai K, Fukuda S, Yamaguti K, Kuratsune H, Soga T, Watanabe Y, Kataoka Y. Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles. Sci Rep. 2016 Oct 11;6:34990. doi: 10.1038/srep34990. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5057083/ (Full article)

 

Chronic fatigue syndrome and mitochondrial dysfunction

Abstract:

This study aims to improve the health of patients suffering from chronic fatigue syndrome (CFS) by interventions based on the biochemistry of the illness, specifically the function of mitochondria in producing ATP (adenosine triphosphate), the energy currency for all body functions, and recycling ADP (adenosine diphosphate) to replenish the ATP supply as needed.

Patients attending a private medical practice specializing in CFS were diagnosed using the Centers for Disease Control criteria. In consultation with each patient, an integer on the Bell Ability Scale was assigned, and a blood sample was taken for the “ATP profile” test, designed for CFS and other fatigue conditions. Each test produced 5 numerical factors which describe the availability of ATP in neutrophils, the fraction complexed with magnesium, the efficiency of oxidative phosphorylation, and the transfer efficiencies of ADP into the mitochondria and ATP into the cytosol where the energy is used. With the consent of each of 71 patients and 53 normal, healthy controls the 5 factors have been collated and compared with the Bell Ability Scale.

The individual numerical factors show that patients have different combinations of biochemical lesions. When the factors are combined, a remarkable correlation is observed between the degree of mitochondrial dysfunction and the severity of illness (P<0.001). Only 1 of the 71 patients overlaps the normal region.

The “ATP profile” test is a powerful diagnostic tool and can differentiate patients who have fatigue and other symptoms as a result of energy wastage by stress and psychological factors from those who have insufficient energy due to cellular respiration dysfunction. The individual factors indicate which remedial actions, in the form of dietary supplements, drugs and detoxification, are most likely to be of benefit, and what further tests should be carried out.

 

Source: Myhill S, Booth NE, McLaren-Howard J. Chronic fatigue syndrome and mitochondrial dysfunction. Int J Clin Exp Med. 2009;2(1):1-16. Epub 2009 Jan 15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2680051/ (Full article)

 

Visible and near-infrared spectral changes in the thumb of patients with chronic fatigue syndrome

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) patients show a persistent fatigue condition with muscle pain and impairment of concentration, memory, and sleep. Presently, the physiological basis of CFS remains unclear. In this study, spectroscopic differences in the thumb were compared between 103 CFS patients and 122 healthy controls to examine possible changes of levels of oxygenated or deoxygenated hemoglobin.

METHODS: Visible and near-infrared (Vis-NIR) spectroscopy was used to examine possible changes in the region of 600-1100 nm.

RESULTS: Vis-NIR spectra showed sharp peaks at 694, 970 and 1060 nm and broad peaks in the regions of 740-760 and 830-850 nm. As these peaks are possibly related to oxyhemoglobin, cytochrome c oxidase and water, levels of these factors were compared between the two groups. Statistical analysis of the absorbance of Vis-NIR spectra showed a significant decrease in water content, a significant increase in oxyhemoglobin content, and a significant increase in the oxidation of heme a+a(3) and copper in cytochrome c oxidase in CFS patients.

CONCLUSIONS: These changes imply accelerated blood flow and energy metabolism in the thumbs of CFS patients.

 

Source: Sakudo A, Kato YH, Tajima S, Kuratsune H, Ikuta K. Visible and near-infrared spectral changes in the thumb of patients with chronic fatigue syndrome. Clin Chim Acta. 2009 May;403(1-2):163-6. doi: 10.1016/j.cca.2009.02.010. Epub 2009 Feb 25. https://www.ncbi.nlm.nih.gov/pubmed/19248775

 

In vivo magnetic resonance spectroscopy in chronic fatigue syndrome

Abstract:

The pathogenic mechanisms of chronic fatigue syndrome (CFS) are not clearly known. Fatigue, poor short-term memory and muscle pain are the most disabling symptoms in CFS. Research data on magnetic resonance spectroscopy (MRS) of muscles and brain in CFS patients suggest a cellular metabolic abnormality in some cases.

31P MRS of skeletal muscles in a subset of patients indicate early intracellular acidosis in the exercising muscles. 1H MRS of the regional brain areas in CFS have shown increased peaks of choline derived from the cell membrane phospholipids.

Cell membrane oxidative stress may offer a common explanation for the observed MRS changes in the muscles and brain of CFS patients and this may have important therapeutic implications. As a research tool, MRS may be used as an objective outcome measure in the intervention studies. In addition, regional brain 1H MRS has the potential for wider use to substantiate a clinical diagnosis of CFS from other disorders of unexplained chronic fatigue.

 

Source: Chaudhuri A, Behan PO. In vivo magnetic resonance spectroscopy in chronic fatigue syndrome. Prostaglandins Leukot Essent Fatty Acids. 2004 Sep;71(3):181-3. http://www.ncbi.nlm.nih.gov/pubmed/15253888