scholarly journals A Link between Mitochondrial Dysregulation and Idiopathic Autism Spectrum Disorder (ASD): Alterations in Mitochondrial Respiratory Capacity and Membrane Potential

2021 ◽  
Vol 43 (3) ◽  
pp. 2238-2252
Author(s):  
Hazirah Hassan ◽  
Fazaine Zakaria ◽  
Suzana Makpol ◽  
Norwahidah Abdul Karim
Keyword(s):  
Autism Spectrum Disorder ◽  
Electron Transfer ◽  
Membrane Potential ◽  
Mitochondrial Function ◽  
Complex I ◽  
Autism Spectrum ◽  
Complex Iv ◽  
Respiratory Capacity ◽  
Complex Ii ◽  
Mitochondrial Respiratory

Autism spectrum disorder (ASD) is a neurological disorder triggered by various factors through complex mechanisms. Research has been done to elucidate the potential etiologic mechanisms in ASD, but no single cause has been confirmed. The involvement of oxidative stress is correlated with ASD and possibly affects mitochondrial function. This study aimed to elucidate the link between mitochondrial dysregulation and idiopathic ASD by focusing on mitochondrial respiratory capacity and membrane potential. Our findings showed that mitochondrial function in the energy metabolism pathway was significantly dysregulated in a lymphoblastoid cell line (LCL) derived from an autistic child (ALCL). Respiratory capacities of oxidative phosphorylation (OXPHOS), electron transfer of the Complex I and Complex II linked pathways, membrane potential, and Complex IV activity of the ALCL were analyzed and compared with control cell lines derived from a developmentally normal non-autistic sibling (NALCL). All experiments were performed using high-resolution respirometry. Respiratory capacities of OXPHOS, electron transfer of the Complex I- and Complex II-linked pathways, and Complex IV activity of the ALCL were significantly higher compared to healthy controls. Mitochondrial membrane potential was also significantly higher, measured in the Complex II-linked pathway during LEAK respiration and OXPHOS. These results indicate the abnormalities in mitochondrial respiratory control linking mitochondrial function with autism. Correlating mitochondrial dysfunction and autism is important for a better understanding of ASD pathogenesis in order to produce effective interventions.

scholarly journals Mitochondrial morphology is associated with respiratory chain uncoupling in autism spectrum disorder

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard E. Frye ◽  
Loïc Lionnard ◽  
Indrapal Singh ◽  
Mohammad A. Karim ◽  
Hanane Chajra ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Complex I ◽  
Molecular Mechanisms ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Mitochondrial Metabolism ◽  
Spectrum Disorder ◽  
Mitochondrial Morphology ◽  
Complex Iv ◽  
Children With Asd

AbstractAutism spectrum disorder (ASD) is a neurodevelopmental disorder that is associated with unique changes in mitochondrial metabolism, including elevated respiration rates and morphological alterations. We examined electron transport chain (ETC) complex activity in fibroblasts derived from 18 children with ASD as well as mitochondrial morphology measurements in fibroblasts derived from the ASD participants and four typically developing controls. In ASD participants, symptoms severity was measured by the Social Responsiveness Scale and Aberrant Behavior Checklist. Mixed-model regression demonstrated that alterations in mitochondrial morphology were associated with both ETC Complex I+III and IV activity as well as the difference between ETC Complex I+III and IV activity. The subgroup of ASD participants with relative elevation in Complex IV activity demonstrated more typical mitochondrial morphology and milder ASD related symptoms. This study is limited by sample size given the invasive nature of obtaining fibroblasts from children. Furthermore, since mitochondrial function is heterogenous across tissues, the result may be specific to fibroblast respiration. Previous studies have separately described elevated ETC Complex IV activity and changes in mitochondrial morphology in cells derived from children with ASD but this is the first study to link these two findings in mitochondrial metabolism. The association between a difference in ETC complex I+III and IV activity and normal morphology suggests that mitochondrial in individuals with ASD may require ETC uncoupling to function optimally. Further studies should assess the molecular mechanisms behind these unique metabolic changes.Trial registration: Protocols used in this study were registered in clinicaltrials.gov as NCT02000284 and NCT02003170.

scholarly journals An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients

2020 ◽  
Author(s):  
Daniel Missailidis ◽  
Sarah Annesley ◽  
Claire Allan ◽  
Oana Sanislav ◽  
Brett Lidbury ◽  
...  
Keyword(s):  
Steady State ◽  
Fatty Acid ◽  
Mitochondrial Function ◽  
Complex I ◽  
Atp Synthesis ◽  
Beta Oxidation ◽  
Respiratory Capacity ◽  
Respiratory Complexes ◽  
Stress Sensing ◽  
Mitochondrial Respiratory

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is an enigmatic condition characterized by exacerbation of symptoms after exertion (post-exertional malaise or “PEM”), and by fatigue whose severity and associated requirement for rest are excessive and disproportionate to the fatigue-inducing activity. There is no definitive molecular marker or known underlying pathological mechanism for the condition. Increasing evidence for aberrant energy metabolism suggests a role for mitochondrial dysfunction in ME/CFS. Our objective was therefore to measure mitochondrial function and cellular stress sensing in actively metabolising patient blood cells. We immortalized lymphoblasts isolated from 51 ME/CFS patients diagnosed according to the Canadian Consensus Criteria and an age- and gender-matched control group. Parameters of mitochondrial function and energy stress sensing were assessed by Seahorse extracellular flux analysis, proteomics, and an array of additional biochemical assays. As a proportion of the basal oxygen consumption rate (OCR), the rate of ATP synthesis by Complex V was significantly reduced in ME/CFS lymphoblasts, while significant elevations were observed in Complex I OCR, maximum OCR, spare respiratory capacity, nonmitochondrial OCR and “proton leak” as a proportion of the basal OCR. This was accompanied by a reduction of mitochondrial membrane potential, chronically hyperactivated TOR Complex I stress signalling and upregulated expression of mitochondrial respiratory complexes, fatty acid transporters and enzymes of the β-oxidation and TCA cycles. By contrast, mitochondrial mass and genome copy number, as well as glycolytic rates and steady state ATP levels were unchanged. Our results suggest a model in which ME/CFS lymphoblasts have a Complex V defect accompanied by compensatory upregulation of their respiratory capacity that includes the mitochondrial respiratory complexes, membrane transporters and enzymes involved in fatty acid β-oxidation. This homeostatically returns ATP synthesis and steady state levels to “normal” in the resting cells, but may leave them unable to adequately respond to acute increases in energy demand as the relevant homeostatic pathways are already activated.

Abstract 284: Elevation of Cardiac NAD+ Levels Improves Mitochondrial Function in Mice Lacking Sirtuin 3

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Matthew A Walker ◽  
Rong Tian
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Function ◽  
Complex I ◽  
Mitochondrial Membrane ◽  
Cardiac Tissue ◽  
Activity Level ◽  
Sirtuin 3 ◽  
Nadh Ratio ◽  
Mitochondrial Respiratory

The mitochondria rely heavily on the ratio between NAD+ and its reduced form NADH to maintain proper function and generate 95% of cardiac cellular energy. Sirtuin 3 (SIRT3) is the major mitochondrial deacetylase and its activity level has been linked to the NAD+/NADH ratio. Numerous studies have shown that deletion of SIRT3 results in hyperacetylation and impairment of mitochondrial enzymes involved in fatty acid metabolism and in the mitochondrial respiratory chain. Because impairments in these processes have shown to be associated with decreases in the NAD+/NADH ratio and contribute to deficits in energy production, we hypothesized that the SIRT3 knockout mice (SIRT3 -/- ) would have a decreased NAD+/NADH ratio and that normalizing the ratio would improve mitochondrial respiratory function and inner membrane potential. In the present study, we observed increases in both NAD+ (1.1-fold, n=3, p<0.05) and NADH (1.5-fold) in cardiac tissue from 14-week old SIRT3 -/- mice compared to wild-type (WT) controls, resulting in a 26±2.2% reduction in the NAD+/NADH ratio. These changes correlated with decreased Complex I ADP stimulated respiration (173±16 vs 118±14 nmolO 2 /min/mg for WT and SIRT3 -/- , respectively, n=3, p<0.05) and suppressed mitochondrial membrane potential. Intraperitoneal injection (I.P.) of Nicotinamide Riboside (NR) increased NAD+ levels in cardiac tissue lysates (WT 1.5-fold and SIRT3 -/- 1.4-fold, n=5, p<0.05) and in mitochondria isolated (WT 1.9-fold and SIRT3 -/- 1.7-fold) from the mice with no significant changes in NADH levels. Therefore, the NR I.P. injections normalized the NAD+/NADH ratio, partially restored the Complex I supported mitochondrial respiration (123±11 vs 157±8 nmolO 2 /min/mg for vehicle and NR treated SIRT3 -/- mice, respectively, n=3, p<0.05), and improved mitochondrial membrane potential in the SIRT3 -/- mice. These results suggest that increasing cardiac NAD+ levels can rescue mitochondrial dysfunction independent of SIRT3 protein deacetylation and warrants further investigation. The next step will be to test whether increasing cardiac NAD+ levels can improve mitochondrial function and reduce injury in SIRT3 -/- mice subjected to chronic heart stress induced by transverse aortic constriction surgery.

scholarly journals An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients

2020 ◽  
Vol 21 (3) ◽  
pp. 1074 ◽  
Author(s):  
Daniel Missailidis ◽  
Sarah J. Annesley ◽  
Claire Y. Allan ◽  
Oana Sanislav ◽  
Brett A. Lidbury ◽  
...  
Keyword(s):  
Steady State ◽  
Fatty Acid ◽  
Mitochondrial Function ◽  
Complex I ◽  
Atp Synthesis ◽  
Resting Cells ◽  
Respiratory Capacity ◽  
Respiratory Complexes ◽  
Stress Sensing ◽  
Mitochondrial Respiratory

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an enigmatic condition characterized by exacerbation of symptoms after exertion (post-exertional malaise or “PEM”), and by fatigue whose severity and associated requirement for rest are excessive and disproportionate to the fatigue-inducing activity. There is no definitive molecular marker or known underlying pathological mechanism for the condition. Increasing evidence for aberrant energy metabolism suggests a role for mitochondrial dysfunction in ME/CFS. Our objective was therefore to measure mitochondrial function and cellular stress sensing in actively metabolizing patient blood cells. We immortalized lymphoblasts isolated from 51 ME/CFS patients diagnosed according to the Canadian Consensus Criteria and an age- and gender-matched control group. Parameters of mitochondrial function and energy stress sensing were assessed by Seahorse extracellular flux analysis, proteomics, and an array of additional biochemical assays. As a proportion of the basal oxygen consumption rate (OCR), the rate of ATP synthesis by Complex V was significantly reduced in ME/CFS lymphoblasts, while significant elevations were observed in Complex I OCR, maximum OCR, spare respiratory capacity, nonmitochondrial OCR and “proton leak” as a proportion of the basal OCR. This was accompanied by a reduction of mitochondrial membrane potential, chronically hyperactivated TOR Complex I stress signaling and upregulated expression of mitochondrial respiratory complexes, fatty acid transporters, and enzymes of the β-oxidation and TCA cycles. By contrast, mitochondrial mass and genome copy number, as well as glycolytic rates and steady state ATP levels were unchanged. Our results suggest a model in which ME/CFS lymphoblasts have a Complex V defect accompanied by compensatory upregulation of their respiratory capacity that includes the mitochondrial respiratory complexes, membrane transporters and enzymes involved in fatty acid β-oxidation. This homeostatically returns ATP synthesis and steady state levels to “normal” in the resting cells, but may leave them unable to adequately respond to acute increases in energy demand as the relevant homeostatic pathways are already activated.

scholarly journals An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients

2020 ◽  
Author(s):  
Daniel Missailidis ◽  
Sarah Annesley ◽  
Claire Allan ◽  
Oana Sanislav ◽  
Brett Lidbury ◽  
...  
Keyword(s):  
Steady State ◽  
Fatty Acid ◽  
Mitochondrial Function ◽  
Complex I ◽  
Atp Synthesis ◽  
Beta Oxidation ◽  
Respiratory Capacity ◽  
Respiratory Complexes ◽  
Stress Sensing ◽  
Mitochondrial Respiratory

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is an enigmatic condition characterized by exacerbation of symptoms after exertion (post-exertional malaise or &ldquo;PEM&rdquo;), and by fatigue whose severity and associated requirement for rest are excessive and disproportionate to the fatigue-inducing activity. There is no definitive molecular marker or known underlying pathological mechanism for the condition. Increasing evidence for aberrant energy metabolism suggests a role for mitochondrial dysfunction in ME/CFS. Our objective was therefore to measure mitochondrial function and cellular stress sensing in actively metabolising patient blood cells. We immortalized lymphoblasts isolated from 51 ME/CFS patients diagnosed according to the Canadian Consensus Criteria and an age- and gender-matched control group. Parameters of mitochondrial function and energy stress sensing were assessed by Seahorse extracellular flux analysis, proteomics, and an array of additional biochemical assays. As a proportion of the basal oxygen consumption rate (OCR), the rate of ATP synthesis by Complex V was significantly reduced in ME/CFS lymphoblasts, while significant elevations were observed in Complex I OCR, maximum OCR, spare respiratory capacity, nonmitochondrial OCR and &ldquo;proton leak&rdquo; as a proportion of the basal OCR. This was accompanied by a reduction of mitochondrial membrane potential, chronically hyperactivated TOR Complex I stress signalling and upregulated expression of mitochondrial respiratory complexes, fatty acid transporters and enzymes of the &beta;-oxidation and TCA cycles. By contrast, mitochondrial mass and genome copy number, as well as glycolytic rates and steady state ATP levels were unchanged. Our results suggest a model in which ME/CFS lymphoblasts have a Complex V defect accompanied by compensatory upregulation of their respiratory capacity that includes the mitochondrial respiratory complexes, membrane transporters and enzymes involved in fatty acid &beta;-oxidation. This homeostatically returns ATP synthesis and steady state levels to &ldquo;normal&rdquo; in the resting cells, but may leave them unable to adequately respond to acute increases in energy demand as the relevant homeostatic pathways are already activated.

scholarly journals An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients

2019 ◽  
Author(s):  
Daniel Missailidis ◽  
Sarah Annesley ◽  
Claire Allan ◽  
Oana Sanislav ◽  
Brett Lidbury ◽  
...  
Keyword(s):  
Steady State ◽  
Fatty Acid ◽  
Mitochondrial Function ◽  
Complex I ◽  
Atp Synthesis ◽  
Beta Oxidation ◽  
Respiratory Capacity ◽  
Respiratory Complexes ◽  
Stress Sensing ◽  
Mitochondrial Respiratory

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is an enigmatic condition characterized by fatigue that is unaided by rest and by exacerbation of symptoms after exertion (post-exertional malaise or &ldquo;PEM&rdquo;). There is no definitive molecular marker or known underlying pathological mechanism for the condition. Increasing evidence for aberrant energy metabolism suggests a role for mitochondrial dysfunction in ME/CFS. Our objective was therefore to measure mitochondrial function and cellular stress sensing in actively metabolising patient blood cells. We immortalized lymphoblasts isolated from 51 ME/CFS patients diagnosed according to the Canadian Consensus Criteria and an age- and gender-matched control group. Parameters of mitochondrial function and energy stress sensing were assessed by Seahorse extracellular flux analysis, proteomics, and an array of additional biochemical assays. As a proportion of the basal oxygen consumption rate (OCR), the rate of ATP synthesis by Complex V was significantly reduced in ME/CFS lymphoblasts, while significant elevations were observed in Complex I OCR, maximum OCR, spare respiratory capacity, nonmitochondrial OCR and &ldquo;proton leak&rdquo; as a proportion of the basal OCR. This was accompanied by an elevation of mitochondrial membrane potential, chronically hyperactivated TOR Complex I stress signalling and upregulated expression of mitochondrial respiratory complexes, fatty acid transporters and enzymes of the &beta;-oxidation and TCA cycles. By contrast, mitochondrial mass and genome copy number, as well as glycolytic rates and steady state ATP levels were unchanged. Our results suggest a model in which ME/CFS lymphoblasts have a Complex V defect accompanied by compensatory upregulation of their respiratory capacity that includes the mitochondrial respiratory complexes, membrane transporters and enzymes involved in fatty acid &beta;-oxidation. This homeostatically returns ATP synthesis and steady state levels to &ldquo;normal&rdquo; in resting cells, but may leave them unable to adequately respond to acute increases in energy demand as the relevant homeostatic pathways are already activated.

scholarly journals Administration of Harmine and Imipramine Alters Creatine Kinase and Mitochondrial Respiratory Chain Activities in the Rat Brain

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Gislaine Z. Réus ◽  
Roberto B. Stringari ◽  
Cinara L. Gonçalves ◽  
Giselli Scaini ◽  
Milena Carvalho-Silva ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Rat Brain ◽  
Respiratory Chain ◽  
Complex I ◽  
Acute Treatment ◽  
Chronic Treatment ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iv ◽  
Complex Ii ◽  
Mitochondrial Respiratory

The present study evaluated mitochondrial respiratory chain and creatine kinase activities after administration of harmine (5, 10, and 15 mg/kg) and imipramine (10, 20, and 30 mg/kg) in rat brain. After acute treatment occurred an increase of creatine kinase in the prefrontal with imipramine (20 and 30 mg/kg) and harmine in all doses, in the striatum with imipramine (20 and 30 mg/kg) and harmine (5 and 10 mg/kg); harmine (15 mg/kg) decreased creatine kinase. In the chronic treatment occurred an increase of creatine kinase with imipramine (20 mg/kg), harmine (5 mg/kg) in the prefrontal with imipramine (20 and 30 mg/kg) and harmine (5 and 10 mg/kg) in the striatum. In the acute treatment, the complex I increased in the prefrontal with harmine (15 mg/kg) and in the striatum with harmine (10 mg/kg); the complex II decreased with imipramine (20 and 30 mg/kg) in the striatum; the complex IV increased with imipramine (30 mg/kg) in the striatum. In the chronic treatment, the complex I increased with harmine (5 mg/kg) in the prefrontal; the complex II increased with imipramine (20 mg/kg) in the prefrontal; the complex IV increased with harmine (5 mg/kg) in the striatum. Finally, these findings further support the hypothesis that harmine and imipramine could be involved in mitochondrial function.

scholarly journals Atorvastatin impairs liver mitochondrial function in obese Göttingen Minipigs but heart and skeletal muscle are not affected

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liselotte Bruun Christiansen ◽  
Tine Lovsø Dohlmann ◽  
Trine Pagh Ludvigsen ◽  
Ewa Parfieniuk ◽  
Michal Ciborowski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Function ◽  
Citrate Synthase ◽  
Obese Group ◽  
Control Group ◽  
Dependent Manner ◽  
Respiratory Capacity ◽  
Protein Carbonyl Content ◽  
Functional Changes ◽  
Mitochondrial Respiratory

AbstractStatins lower the risk of cardiovascular events but have been associated with mitochondrial functional changes in a tissue-dependent manner. We investigated tissue-specific modifications of mitochondrial function in liver, heart and skeletal muscle mediated by chronic statin therapy in a Göttingen Minipig model. We hypothesized that statins enhance the mitochondrial function in heart but impair skeletal muscle and liver mitochondria. Mitochondrial respiratory capacities, citrate synthase activity, coenzyme Q10 concentrations and protein carbonyl content (PCC) were analyzed in samples of liver, heart and skeletal muscle from three groups of Göttingen Minipigs: a lean control group (CON, n = 6), an obese group (HFD, n = 7) and an obese group treated with atorvastatin for 28 weeks (HFD + ATO, n = 7). Atorvastatin concentrations were analyzed in each of the three tissues and in plasma from the Göttingen Minipigs. In treated minipigs, atorvastatin was detected in the liver and in plasma. A significant reduction in complex I + II-supported mitochondrial respiratory capacity was seen in liver of HFD + ATO compared to HFD (P = 0.022). Opposite directed but insignificant modifications of mitochondrial respiratory capacity were seen in heart versus skeletal muscle in HFD + ATO compared to the HFD group. In heart muscle, the HFD + ATO had significantly higher PCC compared to the HFD group (P = 0.0323). In the HFD group relative to CON, liver mitochondrial respiration decreased whereas in skeletal muscle, respiration increased but these changes were insignificant when normalizing for mitochondrial content. Oral atorvastatin treatment in Göttingen Minipigs is associated with a reduced mitochondrial respiratory capacity in the liver that may be linked to increased content of atorvastatin in this organ.

scholarly journals Estradiol treatment or modest exercise improves hepatic health and mitochondrial outcomes in female mice following ovariectomy

2021 ◽  
Author(s):  
Kelly N. Z. Fuller ◽  
Colin S. McCoin ◽  
Alex T. Von Schulze ◽  
Claire J. Houchen ◽  
Michael A. Choi ◽  
...  
Keyword(s):  
Bile Acid ◽  
Mitochondrial Function ◽  
High Fat Diet ◽  
Acid Metabolism ◽  
Bile Acid Metabolism ◽  
High Fat ◽  
Estradiol Treatment ◽  
Respiratory Capacity ◽  
Female Mice ◽  
Mitochondrial Respiratory

We recently reported that compared to males, female mice have increased hepatic mitochondrial respiratory capacity and are protected against high-fat diet-induced steatosis. Here we sought to determine the role of estrogen in hepatic mitochondrial function, steatosis, and bile acid metabolism in female mice, as well as investigate potential benefits of exercise in the absence or presence of estrogen via ovariectomy (OVX). Female C57BL mice (n=6 per group) were randomly assigned to sham surgery (Sham), ovariectomy (OVX), or OVX plus estradiol replacement therapy (OVX+Est). Half of the mice in each treatment group were sedentary (SED) or had access to voluntary wheel running (VWR). All mice were fed a high-fat diet (HFD) and were housed at thermoneutral temperatures. We assessed isolated hepatic mitochondrial respiratory capacity using the Oroboros O2k with both pyruvate and palmitoylcarnitine as substrates. As expected, OVX mice presented with greater hepatic steatosis, weight gain, and fat mass gain compared to Sham and OVX+Est animals. Hepatic mitochondrial coupling (Basal/State 3 respiration) with pyruvate was impaired following OVX, but both VWR and estradiol treatment rescued coupling to levels greater than or equal to Sham animals. Estradiol and exercise also had different effects on liver electron transport chain protein expression depending on OVX status. Markers of bile acid metabolism and excretion were also impaired by ovariectomy but rescued with estradiol add-back. Together our data suggest that estrogen depletion impairs hepatic mitochondrial function and liver health, and that estradiol replacement and modest exercise can aid in rescuing this phenotype.

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