Tag: cellular energy

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)

The Role of Immunity and Inflammation in ME/ CFS and Post-COVID Syndrome: Implications for Treatment

Abstract:

Probably one in seven patients who have experienced acute COVID-19 continue having long-lasting complaints, called post-COVID syndrome or long-COVID, that are similar to those observed in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

There are good reasons to believe that common immunological, epigenetic and inflammatory mechanisms are involved in the pathogenesis both diseases.

To date, various therapeutic approaches have been recommended, but with moderate success. In the present opinion paper, the author weights his clinical experience against data from the literature, and suggests novel approaches.

In addition to general measures and paramedical approaches, food supplementation with a specific nutraceutical can be completed by oral administration of sodium dichloroacetate and Meldonium to optimize glucose metabolism and mitochondrial energy generation.

Alternatively, intravenous infusions with magnesium salt and multivitamins can be completed with glutathione, m-tranexamic acid, and cultured stem cells.

Preliminary results of an open-label, prospective, two-centre trial suggest more than four in five patients benefit from combined oral and infusion therapy with significantly diminished fatigue and improved well-being.

Monoclonal antibodies in “biologicals”, blocking the effects of cytokines, and “small molecules” with Janus kinase inhibiting activity may offer novel opportunities by focusing on both immunologic and inflammation targets. A pilot trial with, in particular, one of the Janus kinase inhibitors could be considered.

Source: Comhaire F. The Role of Immunity and Inflammation in ME/CFS and Post-COVID Syndrome: Implications for Treatment. MedLife Clinics 2022, Volume 4 (2), Article 1043 http://www.medtextpublications.com/open-access/the-role-of-immunity-and-inflammation-in-me-cfs-and-1254.pdf (Full text)

Could the kynurenine pathway be the key missing piece of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) complex puzzle?

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex and debilitating disease with a substantial social and economic impact on individuals and their community. Despite its importance and deteriorating impact, progresses in diagnosis and treatment of ME/CFS is limited. This is due to the unclear pathophysiology of the disease and consequently lack of prognostic biomarkers.

To investigate pathophysiology of ME/CFS, several potential pathologic hallmarks have been investigated; however, these studies have failed to report a consistent result. These failures in introducing the underlying reason for ME/CFS have stimulated considering other possible contributing mechanisms such as tryptophan (TRP) metabolism and in particular kynurenine pathway (KP).

KP plays a central role in cellular energy production through the production of nicotinamide adenine dinucleotide (NADH). In addition, this pathway has been shown to mediate immune response and neuroinflammation through its metabolites. This review, we will discuss the pathology and management of ME/CFS and provide evidence pertaining KP abnormalities and symptoms that are classic characteristics of ME/CFS. Targeting the KP regulation may provide innovative approaches to the management of ME/CFS.

Source: Kavyani B, Lidbury BA, Schloeffel R, Fisher PR, Missailidis D, Annesley SJ, Dehhaghi M, Heng B, Guillemin GJ. Could the kynurenine pathway be the key missing piece of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) complex puzzle? Cell Mol Life Sci. 2022 Jul 11;79(8):412. doi: 10.1007/s00018-022-04380-5. PMID: 35821534. https://link.springer.com/article/10.1007/s00018-022-04380-5  (Full text)

The role of mitochondria in ME/CFS: a perspective

Abstract:

Chronic fatigue syndrome (CFS) also known as Myalgic encephalomyelitis (ME) is a debilitating disease, characterized by the symptom of severe fatigue. ME/CFS is a heterogeneous condition in both clinical presentation and disease duration. A diagnosis of ME/CFS is based on the exclusion of other diseases due to a current lack of known biomarkers for the disease. Patients may be split into categories based on the severity of their illness – mild, moderate and severe. Here we consider some of the recent advances in the understanding of mitochondrial dysfunction and mitochondrial DNA (mtDNA) variation that may have relevance to ME/CFS.

Thus far, we have shown that ME/CFS patients do not harbor proven mtDNA mutations, another exclusion, albeit an important one. As such this group of patients do not fall within the category of patients with mitochondrial disorder. If ME/CFS patients have some form of mitochondrial dysfunction, the form and cause of this dysfunction is a matter of debate. The current data underlines the need to move from small studies to larger endeavors applying multiple methods to well-defined cohorts with samples taken longitudinally.

Source: Cara Tomas & Joanna L Elson (2019) The role of mitochondria in ME/CFS: a perspective, Fatigue: Biomedicine, Health & Behavior, 7:1, 52-58, DOI: 10.1080/21641846.2019.1580855 https://www.tandfonline.com/doi/abs/10.1080/21641846.2019.1580855  (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.

 

 

Dysregulation of cellular energetics in Gulf War Illness

Abstract:

Gulf War Illness (GWI) is estimated to have affected about one third of the Veterans who participated in the first Persian Gulf War. The symptoms of GWI include chronic neurologic impairments, chronic fatigue syndrome, as well as fibromyalgia and immune system disorders, collectively referred to as chronic multi-symptom illness. Thirty years after the war, we still do not have an effective treatment for GWI. It is necessary to understand the molecular basis of the symptoms of GWI in order to develop appropriate therapeutic strategies. Cellular energetics are critical to the maintenance of cellular homeostasis, a process that is highly dependent on intact mitochondrial function and there is significant evidence from both human studies and animal models that mitochondrial impairments may lead to GWI symptoms.

The available clinical and pre-clinical data suggest that agents that improve mitochondrial function have the potential to restore cellular energetics and treat GWI. To date, the experiments conducted in animal models of GWI have mainly focused on neurobehavioral aspects of the illness. Additional studies to address the fundamental biological processes that trigger the dysregulation of cellular energetics in GWI are warranted to better understand the underlying pathology and to develop new treatment methods. This review highlights studies related to mitochondrial dysfunction observed in both GW veterans and in animal models of GWI.

Source: Raju RP, Terry AV. Dysregulation of cellular energetics in Gulf War Illness. Toxicology. 2021 Aug 10:152894. doi: 10.1016/j.tox.2021.152894. Epub ahead of print. PMID: 34389359. https://pubmed.ncbi.nlm.nih.gov/34389359/

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/

Cell-Based Blood Biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a devastating illness whose biomedical basis is now beginning to be elucidated. We reported previously that, after recovery from frozen storage, lymphocytes (peripheral blood mononuclear cells, PBMCs) from ME/CFS patients die faster in culture medium than those from healthy controls. We also found that lymphoblastoid cell lines (lymphoblasts) derived from these PBMCs exhibit multiple abnormalities in mitochondrial respiratory function and signalling activity by the cellular stress-sensing kinase Target Of Rapamycin Complex 1 (TORC1). These differences were correlated with disease severity, as measured by the Richardson and Lidbury weighted standing test.

The clarity of the differences between these cells derived from ME/CFS patient blood and those from healthy controls suggested that they may provide useful biomarkers for ME/CFS. Here, we report a preliminary investigation into that possibility using a variety of analytical classification tools, including linear discriminant analysis, logistic regression and receiver operating characteristic (ROC) curve analysis.

We found that results from three different tests-lymphocyte death rate, mitochondrial respiratory function and TORC1 activity-could each individually serve as a biomarker with better than 90% sensitivity but only modest specificity vís a vís healthy controls. However, in combination, they provided a cell-based biomarker with sensitivity and specificity approaching 100% in our sample.

This level of sensitivity and specificity was almost equalled by a suggested protocol in which the frozen lymphocyte death rate was used as a highly sensitive test to triage positive samples to the more time consuming and expensive tests measuring lymphoblast respiratory function and TORC1 activity. This protocol provides a promising biomarker that could assist in more rapid and accurate diagnosis of ME/CFS.

Source: Missailidis D, Sanislav O, Allan CY, Annesley SJ, Fisher PR. Cell-Based Blood Biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Int J Mol Sci. 2020 Feb 8;21(3). pii: E1142. doi: 10.3390/ijms21031142. https://www.ncbi.nlm.nih.gov/pubmed/32046336

Circulating levels of GDF15 in patients with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition characterised by fatigue and post-exertional malaise. Its pathogenesis is poorly understood. GDF15 is a circulating protein secreted by cells in response to a variety of stressors. The receptor for GDF15 is expressed in the brain, where its activation results in a range of responses. Among the conditions in which circulating GDF15 levels are highly elevated are mitochondrial disorders, where early skeletal muscle fatigue is a key symptom. We hypothesised that GDF15 may represent a marker of cellular stress in ME/CFS.

METHODS: GDF15 was measured in serum from patients with ME/CFS (n = 150; 100 with mild/moderate and 50 with severe symptoms), “healthy volunteers” (n = 150) and a cohort of patients with multiple sclerosis (n = 50).

RESULTS: Circulating GDF15 remained stable in a subset of ME/CFS patients when sampled on two occasions ~ 7 months (IQR 6.7-8.8) apart, 720 pg/ml (95% CI 625-816) vs 670 pg/ml (95% CI 598-796), P = 0.5. GDF15 levels were 491 pg/ml in controls (95% CI 429-553), 546 pg/ml (95% CI 478-614) in MS patients, 560 pg/ml (95% CI 502-617) in mild/moderate ME/CFS patients and 602 pg/ml (95% CI 531-674) in severely affected ME/CFS patients. Accounting for potential confounders, severely affected ME/CFS patients had GDF15 concentrations that were significantly increased compared to healthy controls (P = 0.01). GDF15 levels were positively correlated (P = 0.026) with fatigue scores in ME/CFS.

CONCLUSIONS: Severe ME/CFS is associated with increased levels of GDF15, a circulating biomarker of cellular stress that appears which stable over several months.

Source: Melvin A, Lacerda E, Dockrell HM, O’Rahilly S, Nacul L. Circulating levels of GDF15 in patients with myalgic encephalomyelitis/chronic fatigue syndrome. J Transl Med. 2019 Dec 4;17(1):409. doi: 10.1186/s12967-019-02153-6. https://www.ncbi.nlm.nih.gov/pubmed/31801546

Assessing cellular energy dysfunction in CFS/ME using a commercially available laboratory test

Abstract:

The mitochondrial energy score (MES) protocol, developed by the Myhill group, is marketed as a diagnostic test for chronic fatigue syndrome/Myalgic Encephalomyelitis (CFS/ME). This study assessed the reliability and reproducibility of the test, currently provided by private clinics, to assess its potential to be developed as an NHS accredited laboratory test.

We replicated the MES protocol using neutrophils and peripheral blood mononuclear cells (PBMCs) from CFS/ME patients (10) and healthy controls (13). The protocol was then repeated in PBMCs and neutrophils from healthy controls to investigate the effect of delayed sample processing time used by the Myhill group.

Experiments using the established protocol showed no differences between CFS/ME patients and healthy controls in any of the components of the MES (p ≥ 0.059). Delaying blood sample processing by 24 hours (well within the 72 hour time frame quoted by the Myhill group) significantly altered many of the parameters used to calculate the MES in both neutrophils and PBMCs. The MES test does not have the reliability and reproducibility required of a diagnostic test and therefore should not currently be offered as a diagnostic test for CFS/ME. The differences observed by the Myhill group may be down to differences in sample processing time between cohorts.

Source: Tomas C, Lodge TA, Potter M, Elson JL, Newton JL, Morten KJ. Assessing cellular energy dysfunction in CFS/ME using a commercially available laboratory test. Sci Rep. 2019 Aug 7;9(1):11464. doi: 10.1038/s41598-019-47966-z. https://www.ncbi.nlm.nih.gov/pubmed/31391529