Distribution of coenzyme Q homologues in brain

Nutraceuticals against Oxidative Stress in Autoimmune Disorders

Antioxidant mechanisms are constituted of enzymes, endogenous, and non-enzymatic, exogenous, which have the role of counterbalancing oxidative stress. Intake of these compounds occurs in the diet. Vegetables, plants, and fruits contain a wide range of alkaloids, polyphenols, and terpenoids which are called “phytochemicals”. Most of these substances are responsible for the positive properties of fruits and vegetables, which are an essential part of a healthy life with roles in ameliorating chronic illnesses and favoring longevity. Nutraceuticals are substances contained in a food or fragment of it influencing health with positive effects on health helping in precenting or treating disorders. We conducted a review illustrating the principal applications of nutraceuticals in autoimmune disorders. Literature reported several studies about exogenous dietary antioxidant supplementation in diverse autoimmune diseases such as rheumatoid arthritis, lupus, diabetes, and multiple sclerosis. In these pathologies, promising results were obtained in some cases. Positive outcomes were generally associated with a reduction of oxidative stress parameters and a boost to antioxidant systems, and sometimes with anti-inflammatory effects. The administration of exogenous substances through food derivates or dietary supplements following scientific standardization was demonstrated to be effective. Further bias-free and extended studies should be conducted that include ever-increasing oxidative stress biomarkers.

Reduction of 2-methoxy-1,4-naphtoquinone by mitochondrially-localized Nqo1 yielding NAD+ supports substrate-level phosphorylation during respiratory inhibition

Provision of NAD⁺ for oxidative decarboxylation of alpha-ketoglutarate to succinyl-CoA by the ketoglutarate dehydrogenase complex (KGDHC) is critical for maintained operation of succinyl-CoA ligase yielding high-energy phosphates, a process known as mitochondrial substrate-level phosphorylation (mSLP). We have shown previously that when NADH oxidation by complex I is inhibited by rotenone or anoxia, mitochondrial diaphorases yield NAD⁺, provided that suitable quinones are present (Kiss G et al., FASEB J 2014, 28:1682). This allows for KGDHC reaction to proceed and as an extension of this, mSLP. NAD(P)H quinone oxidoreductase 1 (NQO1) is an enzyme exhibiting diaphorase activity. Here, by using Nqo1^-/- and WT littermate mice we show that in rotenone-treated, isolated liver mitochondria 2-methoxy-1,4-naphtoquinone (MNQ) is preferentially reduced by matrix Nqo1 yielding NAD⁺ to KGDHC, supporting mSLP. This process was sensitive to inhibition by specific diaphorase inhibitors. Reduction of idebenone and its analogues MRQ-20 and MRQ-56, menadione, mitoquinone and duroquinone were unaffected by genetic disruption of the Nqo1 gene. The results allow for the conclusions that i) MNQ is a Nqo1-preferred substrate, and ii) in the presence of suitable quinones, mitochondrially-localized diaphorases other than Nqo1 support NADH oxidation when complex I is inhibited. Our work confirms that complex I bypass can occur by quinones reduced by intramitochondrial diaphorases oxidizing NADH, ultimately supporting mSLP. Finally, it may help to elucidate structure-activity relationships of redox-active quinones with diaphorase enzymes.

Coenzyme Q10 protects against statin-induced myotoxicity in zebrafish larvae (Danio rerio)

3-Hydroxy-3-methylglutaryl-CoA reductase (HMGCR) is the rate-limiting enzyme of the mevalonic acid pathway and is required for cholesterol biosynthesis and the synthesis of Coenzyme Q10 (CoQ10). Statins inhibit HMGCR, thus inhibiting the downstream products of this pathway including the biosynthesis of decaprenyl-pyrophosphate that is critical for the synthesis of Coenzyme Q10 (CoQ10). We show that zebrafish (Danio rerio) larvae treated in tank water with Atorvastatin (ATV; Lipitor) exhibited movement alterations and reduced whole body tissue metabolism. The ATV-inhibition of HMGCR function altered transcript abundance of muscle atrophy markers (atrogen-1, murf) and the mitochondrial biogenesis marker (pgc-1α). Furthermore, ATV-induced reduction in larval response to tactile stimuli was reversed with treatment of CoQ10. Together, the implication of our results contributes to the understanding of the mechanisms of action of the statin-induced damage in this model fish species.

Intravenous Treatment With Coenzyme Q10 Improves Neurological Outcome and Reduces Infarct Volume After Transient Focal Brain Ischemia in Rats

Coenzyme Q10 (CoQ10) crosses the blood-brain barrier when administered intravenously and accumulates in the brain. In this study, we investigated whether CoQ10 protects against ischemia-reperfusion injury by measuring neurological function and brain infarct volumes in a rat model of transient focal cerebral ischemia. In male Wistar rats, we performed transient middle cerebral artery occlusion (tMCAO) for 60 minutes, followed by reperfusion for 24 hours or 7 days. Forty-five minutes after the onset of occlusion (or 15 minutes before reperfusion), rats received a single intravenous injection of solubilized CoQ10 (30 mg·mL(-1)·kg(-1)) or saline (2 mL/kg). Sensory and motor function scores and body weights were obtained before the rats were killed by decapitation, and brain infarct volumes were calculated using tetrazolium chloride staining. CoQ10 brain levels were measured by high-performance liquid chromatography with electrochemical detection. CoQ10 significantly improved neurological behavior and reduced weight loss up to 7 days after tMCAO (P < 0.05). Furthermore, CoQ10 reduced cerebral infarct volumes by 67% at 24 hours after tMCAO and 35% at 7 days (P < 0.05). Cerebral ischemia resulted in a significant reduction in endogenous CoQ10 in both hemispheres (P < 0.05). However, intravenous injection of solubilized CoQ10 resulted in its increase in both hemispheres at 24 hours and in the contralateral hemisphere at 7 days (P < 0.05). Our results demonstrate that CoQ10 is a robust neuroprotective agent against ischemia-reperfusion brain injury in rats, improving both functional and morphological indices of brain damage.

Brain regional heterogeneity and toxicological mechanisms of organophosphates and carbamates

The brain is a well-organized, yet highly complex, organ in the mammalian system. Most investigators use the whole brain, instead of a selected brain region(s), for biochemical analytes as toxicological endpoints. As a result, the obtained data is often of limited value, since their significance is compromised due to a reduced effect, and the investigators often arrive at an erroneous conclusion(s). By now, a plethora of knowledge reveals the brain regional variability for various biochemical/neurochemical determinants. This review describes the importance of brain regional heterogeneity in relation to cholinergic and noncholinergic determinants with particular reference to organophosphate (OP) and carbamate pesticides and OP nerve agents.

Measurement of oxidized and reduced coenzyme Q in biological fluids, cells, and tissues: an HPLC-EC method

Direct measure of coenzyme Q (CoQ) in biological specimens may provide important advantages. Precise and selective high-performance liquid chromatography (HPLC) methods with electrochemical (EC) detection have been developed for the measurement of reduced (ubiquinol) and oxidized (ubiquinone) CoQ in biological fluids, cells, and tissues. EC detection is preferred for measurement of CoQ because of its high sensitivity. Reduced and oxidized CoQ are first extracted from biological specimens using 1-propanol. After centrifugation, the 1-propanol supernatant is directly injected into HPLC and monitored at a dual-electrode. The EC reactions occur at the electrode surface. The first electrode transforms ubiquinone into ubiquinol, and the second electrode measures the current produced by the oxidation of the hydroquinone group of ubiquinol. The methods described provide rapid, precise, and simple procedures for determination of reduced and oxidized CoQ in biological fluids, cells, and tissues. The methods have been successfully adapted to meet regulatory requirements for clinical laboratories, and have been proven reliable for analysis of clinical and research samples for clinical trials and animal studies involving large numbers of specimens.

Amyotrophic lateral sclerosis-like conditions in possible association with cholesterol-lowering drugs: an analysis of patient reports to the University of California, San Diego (UCSD) Statin Effects Study

BACKGROUND

While cases of amyotrophic lateral sclerosis (ALS) or ALS-like conditions have arisen in apparent association with HMG-CoA reductase inhibitors ('statins') and/or other lipid-lowering drugs (collectively termed 'statins' in this paper for brevity), additional information is needed to understand whether the connection may be causal. The University of California, San Diego (UCSD) Statin Effects Study is a patient-targeted adverse event surveillance project focused on lipid-lowering agents, whose aim is to capitalize on patient reporting to further define characteristics and natural history of statin adverse effects (AEs), and to ascertain whether a patient-targeted surveillance system might lead to presumptive identification of previously unrecognized AEs. ALS was a candidate 'new' AE identified through this process. The aim of the analysis presented here was to examine characteristics and natural history of reported statin-associated ALS-like conditions with attention to factors that may bear on the issue of causality.

METHODS

For the present analysis, we focused on cases of statin-associated ALS that were reported to our study group prior to publication of a possible statin-ALS association. Of 35 identified subjects who had contacted the UCSD Statin Effects Study group to report ALS or an ALS-like condition, 18 could not be reached (e.g. contact information was no longer valid). Six were unable to participate (e.g. due to progression of their disease). Of the 11 who could be contacted and were able to participate, one declined to give informed consent. The remaining ten, with either a formal or probable diagnosis of ALS in the context of progressive muscle wasting/weakness arising in association with lipid-lowering drug therapy, completed a mail or phone survey eliciting information about ALS symptom onset and change in association with drug use/modification and development of statin-associated AEs. We reviewed findings in the context of literature on statin antioxidant/pro-oxidant balance, as well as ALS mechanisms involving oxidative stress and mitochondrial dysfunction.

RESULTS

All ten subjects reported amelioration of symptoms with drug discontinuation and/or onset or exacerbation of symptoms with drug change, rechallenge or dose increase. Three subjects initiated coenzyme Q10 supplementation; all reported initial benefit. All subjects reportedly developed statin AEs (not indicative of ALS) prior to ALS symptom onset, strongly disproportionate to expectation (p < 0.001). Since this reflects induction of pro-oxidant effects from statins, these findings lend weight to a literature-supported mechanism by which induction by statins of oxidative stress with amplification of mitochondrial dysfunction, arising in a vulnerable subgroup, may propel mechanisms underlying both AEs and, more rarely, ALS.

CONCLUSION

A theoretical foundation and preliminary clinical observations suggest that statins (and other lipid-lowering drugs) may rarely be associated with ALS in vulnerable individuals in whom pro-oxidant effects of statins predominate. Our observations have explanatory relevance extending to ALS causes that are not statin associated and to statin-associated neurodegenerative conditions that are not ALS. They suggest means for identification of a possible vulnerable subgroup. Indeed whether statins may, in contrast, confer ALS protection when antioxidant effects predominate merits examination.

Effect of dopaminergic neurotoxin MPTP/MPP+ on coenzyme Q content

Coenzyme Q10, an endogenous lipophilic antioxidant, plays an indispensable role in ATP synthesis. The therapeutic value of coenzyme Q10 in Parkinson's disease and other neurodegenerative disorders is still being tested and the preliminary results are promising. The 1-methyl-4-phenyl-1, 2, 3, 6 tetrahydropyridine (MPTP)-treated mouse is a valid and accepted animal model for Parkinson's disease. 1-methyl-4-phenylpyridinium (MPP(+)) is an active toxic metabolite of MPTP. MPP(+) and MPTP are known to induce oxidative stress and mitochondrial dysfunction. However, the effect of MPP(+) and MPTP on coenzyme Q is not clearly understood. The present study investigated the in vitro and in vivo effect of MPP(+) and MPTP on coenzyme Q content. Coenzyme Q content was measured using HPLC-UV detection methods. In the in vitro studies, MPP(+) (0-50 microM) was incubated with SH-SY5Y human neuroblastoma cells and NG-108-15 (mouse/rat, neuroblastomaxglioma hybrid) cells. MPP(+) concentration dependently increased coenzyme Q10 content in SH-SY5Y cells. In NG-108-15 cells, MPP(+) concentration dependently increased both coenzyme Q9 and Q10 content. In the in vivo study, mice were administered with MPTP (30 mg/kg, twice 16 h apart) and sacrificed one week after the last administration. Administration of MPTP to mice significantly increased coenzyme Q9 and coenzyme Q10 levels in the nigrostriatal tract. However, MPTP did not affect the coenzyme Q content in the cerebellum, cortex and pons. This study demonstrated that MPP(+)/MPTP significantly affected the coenzyme Q content in the SH-SY5Y and NG-108 cells and in the mouse nigrostriatal tract.

Comparison of biochemical effects of statins and fish oil in brain: the battle of the titans

Neural membranes are composed of glycerophospholipids, sphingolipids, cholesterol and proteins. The distribution of these lipids within the neural membrane is not random but organized. Neural membranes contain lipid rafts or microdomains that are enriched in sphingolipids and cholesterol. These rafts act as platforms for the generation of glycerophospholipid-, sphingolipid-, and cholesterol-derived second messengers, lipid mediators that are necessary for normal cellular function. Glycerophospholipid-derived lipid mediators include eicosanoids, docosanoids, lipoxins, and platelet-activating factor. Sphingolipid-derived lipid mediators include ceramides, ceramide 1-phosphates, and sphingosine 1-phosphate. Cholesterol-derived lipid mediators include 24-hydroxycholesterol, 25-hydroxycholesterol, and 7-ketocholesterol. Abnormal signal transduction processes and enhanced production of lipid mediators cause oxidative stress and inflammation. These processes are closely associated with the pathogenesis of acute neural trauma (stroke, spinal cord injury, and head injury) and neurodegenerative diseases such as Alzheimer disease. Statins, the HMG-CoA reductase inhibitors, are effective lipid lowering agents that significantly reduce risk for cardiovascular and cerebrovascular diseases. Beneficial effects of statins in neurological diseases are due to their anti-excitotoxic, antioxidant, and anti-inflammatory properties. Fish oil omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, have similar anti-excitotoxic, antioxidant and anti-inflammatory effects in brain tissue. Thus the lipid mediators, resolvins, protectins, and neuroprotectins, derived from eicosapentaenoic acid and docosahexaenoic acid retard neuroinflammation, oxidative stress, and apoptotic cell death in brain tissue. Like statins, ingredients of fish oil inhibit generation of beta-amyloid and provide protection from oxidative stress and inflammatory processes. Collective evidence suggests that antioxidant, anti-inflammatory, and anti-apoptotic properties of statins and fish oil contribute to the clinical efficacy of treating neurological disorders with statins and fish oil. We speculate that there is an overlap between neurochemical events associated with neural cell injury in stroke and neurodegenerative diseases. This commentary compares the neurochemical effects of statins with those of fish oil.

Study of potential systemic oxidative stress animal models for the evaluation of antioxidant activity: status of lipid peroxidation and fat-soluble antioxidants

Although many compounds have already been tested in-vitro to determine their antioxidant profile, it is necessary to investigate the in-vivo effect of potential antioxidants. However, representative models of systemic oxidative stress have been poorly studied. Here, different potential systemic oxidative stress animal models have been investigated. These included a vitamin E-deficient rat, a diabetic rat and an atherosclerotic rabbit model. Plasma/serum malondialdehyde was measured as a parameter of oxidative damage. Plasma/serum fat-soluble antioxidants were determined as markers of antioxidant defence. We demonstrated that vitamin E-deficient rats were not suitable as a model of systemic oxidative stress, whereas diabetic and atherosclerotic animals showed increased systemic oxidative damage, as reflected by significantly augmented plasma/serum malondialdehyde. Moreover, plasma coenzyme Q9 increased by 80% in diabetic rats, confirming systemic oxidative stress. In view of these observations and economically favouring factors, the diabetic rat appeared to be the most appropriate systemic oxidative stress model. These findings have provided important information concerning systemic oxidative stress animal models for the in-vivo study of antioxidants.

Chronological distribution of Rip immunoreactivity in the gerbil hippocampus during normal aging

Age-dependent studies on oligodendrocytes, which are the myelinating cells in the central nervous system, have been relatively less investigated. We examined age-dependent changes in Rip immunoreactivity and its protein level in the gerbil hippocampus during normal aging using immunohistochemistry and Western blot analysis with Rip antibody, an oligodendrocyte marker. Rip immunoreactivity and its protein level in the hippocampal CA1 region significantly increased at postnatal month 3 (PM 3). Thereafter, they decreased in the hippocampal CA1 region with age. At PM 24, Rip immunoreactive processes in the hippocampal CA1 region markedly decreased in the stratum radiatum. In the hippocampal CA2/3 region and dentate gyrus, the pattern of changes in Rip immunoreactivity and its protein level was similar to those in the hippocampal CA1 region; however, no significant changes were found in the CA2/3 region and dentate gyrus at various age stages. These results indicate that Rip immunoreactivity and protein level in the hippocampal CA1 region decreases significantly at PM 24 compared to the CA2/3 region and dentate gyrus.

Quinol fatty alcohols as promoters of axonal growth

The synthesis of three series of quinol fatty alcohols (QFAs) and their biological activities on the promotion of axonal growth are described. Interestingly, the 15-(2,5-dimethoxyphenyl)pentadecan-1-ol, the QFA bearing 15 carbon atoms on the side chain (n=15), shows the most potent promotion of axonal growth in the presence of both permissive and non-permissive naturally occurring substrates such as Sema3A and myelin proteins.

Targeting cellular energy production in neurological disorders

The concepts of energy dysregulation and oxidative stress and their complicated interdependence have rapidly evolved to assume primary importance in understanding the pathophysiology of numerous neurological disorders. Therefore, neuroprotective strategies addressing specific bioenergetic defects hold particular promise in the treatment of these conditions (i.e., amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease, Friedreich's ataxia, mitochondrial cytopathies and other neuromuscular diseases), all of which, to some extent, share 'the final common pathway' leading to cell death through either necrosis or apoptosis. Compounds such as creatine monohydrate and coenzyme Q(10) offer substantial neuroprotection against ischaemia, trauma, oxidative damage and neurotoxins. Miscellaneous agents, including alpha-lipoic acid, beta-OH-beta-methylbutyrate, riboflavin and nicotinamide, have also been shown to improve various metabolic parameters in brain and/or muscle. This review will highlight the biological function of each of the above mentioned compounds followed by a discussion of their utility in animal models and human neurological disease. The balance of this work will be comprised of discussions on the therapeutic applications of creatine and coenzyme Q(10).

An improved method for analyzing coenzyme Q homologues and multiple detection of rare biological samples

We have developed a simple method for the estimation of coenzyme Q homologues, neurotransmitters, metal ions, lipid peroxidation, gene expression, and DNA fragmentation simultaneously from genetically engineered mice brain regions and cultured neurons. The primary objective of this study was to improve conventional time-consuming, cumbersome, and less efficient procedures, and reduce the cost of conducting kinetic studies in rare biological samples. The improved method is novel, precise, efficient, accurate, sensitive, economical, versatile, and highly reproducible. The recovery and shelf life of coenzyme Q homologues was significantly increased and the chromatograms exhibited reduced background and retention times. It is envisaged that in addition to coenzyme Q homologues, the improved method could be utilized for the multiple analyses of DNA, RNA and proteins from clinically significant biopsy and autopsy samples.

Measurement of reduced and oxidized coenzyme Q9 and coenzyme Q10 levels in mouse tissues by HPLC with coulometric detection

BACKGROUND

Ubiquinone-responsive multiple respiratory chain dysfunction due to coenzyme Q(10) (CoQ(10)) deficiency has been previously identified in muscle biopsies. However, previous methods are unreliable for estimating CoQ(10) redox status in tissue. We developed an accurate method for measuring tissue concentrations of reduced and oxidized coenzyme Q (CoQ).

METHODS

Mouse tissues were weighed in the frozen state and homogenized with cold 1-propanol on ice. After solvent extraction, centrifugation and filtration, the filtrate was subsequently analyzed by reversed-phase HPLC with coulometric detection.

RESULTS

Reference calibration curves were used to determine reduced and oxidized coenzyme Q(9) (CoQ(9)) and CoQ(10) concentrations in tissues. The method is sensitive ( approximately 15 microg/l), reproducible (6% CV) for CoQ(9) and CoQ(10), and linear up to 20 mg/l for CoQ(9) and CoQ(10). Analytical recoveries were 90-104%. In mouse tissues the amounts of total CoQ (TQ) ranged from 261 to 1737 nmol/g of protein. Total CoQ(9) levels are comparable with the values of those previously reported. CoQ is found to be mostly in the reduced form in mouse liver ( approximately 87%), heart ( approximately 60%), and muscle tissues ( approximately 58%); in the brain, most of the CoQ is in the oxidized state ( approximately 65%).

CONCLUSION

This procedure provides a precise, sensitive, and direct assay method for the determination of reduced and oxidized CoQ(9) and CoQ(10) in mouse hindleg muscle, heart, brain, and liver tissues.

The immunophilin-ligands FK506 and V-10,367 mediate neuroprotection by the heat shock response

(1) The macrolid FK506 is widely used in transplantation to suppress allograft rejection. FK506 and its derivatives are powerful neuroprotective molecules, but the underlying mechanisms remain to be resolved. We have previously shown that the FK506 mediated neuroprotection against oxygen radicals is independent of the inhibition of calcineurin but depends on de novo protein synthesis. (2) Here, we have shown that FK506 mediates protection against H(2)O(2), UV-light or thapsigargin in neuronal cell lines, but not in non-neuronal cells such as R3T3 fibroblasts. We compared in detail the effect of FK506 on apoptotic features in PC12 cells after H(2)O(2) with V-10,367 which binds to FKBPs but does not inhibit calcineurin. Both molecules exert the same neuroprotective effect after H(2)O(2) stimulation. FK506, but not V-10,367, inhibited the cytochrome c release out of the mitochondria and the caspase 3 activation, while both molecules inhibited the cleavage of Poly-(ADP-ribose)-polymerase (Parp) and prevented the expression of p53. (3) FK506 and V-10,367 rapidly induced the expression of Hsp70 and Hsp27, but not Hsp90. Their neuroprotective actions could be completely blocked by quercetin, a functional inhibitor of the heat shock proteins. (4) We conclude that immunophilin-ligands such as FK506 and V-10,367 exert their neuroprotection independent of calcineurin through the induction of the heat shock response. The identification of the underlying signal transduction from application of immunophilin ligands to the expression of heat shock proteins represents a novel target cascade for neuroprotection.