Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.5.3 (complex I)
8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melatonin is an endogenously generated potent antioxidant. Our previous results indicated that melatonin improved learning and memory deficits in the transgenic mouse model of Alzheimer's disease (AD) and ovariectomized (OVX) rats by improving cholinergic nerve system dysfunction, preventing apoptosis. In this study we aim to investigate the antioxidative effects of melatonin or estradiol in the brains of ovariectomized rats. OVX Sprague-Dawley rats received daily injections of melatonin (5, 10, or 20 mg/kg), 17beta-estradiol (80 microg/kg), or sesame oil for 16 weeks. We found an increase in brain mitochondrial thiobarbituric acid-reactive substances (TBARS) levels, a decrease in mitochondrial glutathione (GSH) content as well as mitochondrial superoxide dismutase (SOD) activity and upregulation of the apoptotic-related factors, such as Bax, Caspase-3, and Prostate apoptosis response-4 (Par-4) in the frontal cortex of OVX rats. In addition to oxidative stress, OVX also caused decreased activities of mitochondrial respiration complex I and complex IV, which implicated mitochondrial dysfunction. Melatonin or 17beta-estradiol antagonized the detrimental effects induced by OVX. Furthermore, immunohistochemistry results revealed that the abnormal upregulation of the apoptotic related factor such as Bax, Caspase-3, and (Par-4) greatly reduced expression after melatonin or 17beta-estradiol supplement action. These findings demonstrate the important effects of melatonin or 17beta-estradiol on postmenopausal neuropathy and support the potential application of melatonin in the treatment of dementia in postmenopausal women. Early, long-term melatonin application is a promising strategy which could potentially be applied in a clinical setting.
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PMID:Long-term melatonin or 17beta-estradiol supplementation alleviates oxidative stress in ovariectomized adult rats. 1596 11

Leber's hereditary optic neuropathy (LHON) causes central vision loss from bilateral optic neuropathy. Although 13 mitochondrial DNA (mtDNA) mutations are strongly associated with LHON, only three account for roughly 90% of cases and thus are found in multiple independent LHON families. The remaining LHON mutations are rare. Here, we describe the clinical and genetic characterization of a new LHON mtDNA mutation. The 12848T mutation alters a highly conserved amino acid in the ND5 complex I gene, is not found in controls, and is heteroplasmic. Despite ND5 being the largest of the mtDNA complex I genes, ND5 mutations are quite rare in LHON.
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PMID:The role of the ND5 gene in LHON: characterization of a new, heteroplasmic LHON mutation. 1624 Mar 59

An experimental optic neuropathy model was used to test the hypothesis that methylene blue may protect the retinal ganglion cell layer from neurodegeneration caused by rotenone. Rotenone is a widely used pesticide that inhibits complex I, the first enzyme of the mitochondrial respiratory chain. Complex I dysfunction is linked to the degeneration of retinal ganglion cells in Leber's optic neuropathy. Methylene blue is a reduction-oxidation agent that can act as a powerful antioxidant and also as an enhancer of the electron transport chain, preventing formation of mitochondrial oxygen free radicals and promoting oxygen consumption. The neurodegeneration of the retina was studied in mice with intravitreal microinjection of rotenone alone, or in combination with increasing doses of methylene blue, in one eye, and the vehicle in the contralateral control eye. The effect of rotenone and rotenone plus methylene blue was investigated using two histological stains, complex I and Nissl, and two measurements, morphometric layer thickness and non-biased stereological cell counts. Rotenone induced neurodegeneration in the retinal ganglion cell layer 24 h after injection, as indicated by significant reductions in both the thickness and cell numbers of the retinal ganglion cell layer of eyes microinjected with rotenone as compared to the control eyes. This neurodegeneration was prevented in a dose dependent manner by the injection of methylene blue along with rotenone. It was concluded that rotenone-induced degeneration in the ganglion cell layer can be prevented by intravitreal injection of methylene blue. In vitro experiments showed that methylene blue is both a powerful antioxidant as well as an enhancer of cellular oxygen consumption and is able to reverse the oxidative stress and decrease in oxygen consumption induced by rotenone in brain homogenates. The findings suggest that methylene blue may be a promising neuroprotective agent in optic neuropathy and perhaps other neurodegenerative diseases caused by mitochondrial dysfunction.
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PMID:Methylene blue prevents neurodegeneration caused by rotenone in the retina. 1646 52

Rotenone is a widely used pesticide and fish toxin that inhibits complex I of the mitochondrial respiratory chain. Complex I dysfunction is linked to the degeneration of retinal ganglion cells in Leber's optic neuropathy. To study the association between environmental mitochondrial toxin exposure and neurodegeneration, mice were intravitreally microinjected with rotenone in one eye and with the vehicle dimethyl sulfoxide in the contralateral eye, as a within-subject control. The retinal ganglion cell layer (GCL) of eyes injected with rotenone became significantly thinner than that of the control eyes after 24 h, but not as early as 0.5 h. This reduction was observed using complex I histochemistry and with Nissl staining of cell bodies. After 24 h, retinal nerve fiber layer thickness was reduced by 89% and the number of GCL cells was reduced by 21% in rotenone-treated eyes. Cellular morphometric data (soma area, perimeter, and diameter) did not show overall differences, but there was a preferential reduction in the proportion of larger cells. Therefore, the reduction in GCL thickness 24 h after rotenone microinjection could be accounted for by cell loss and nerve fiber shrinkage, but not by overall soma size change. Rotenone-induced degeneration of the ganglion cell layer may be used as a convenient way to (1) evaluate mechanisms and treatments for the neurodegeneration produced by mitochondrial dysfunction and (2) investigate environmental pesticide contributions to neurodegenerative diseases.
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PMID:Neurodegeneration produced by rotenone in the mouse retina: a potential model to investigate environmental pesticide contributions to neurodegenerative diseases. 1686 19

Dominant optic atrophy (DOA) is characterized by retinal ganglion cell degeneration leading to optic neuropathy. A subset of DOA is caused by mutations in the OPA1 gene, encoding for a dynamin-related GTPase required for mitochondrial fusion. The functional consequences of OPA1 mutations in DOA patients are still poorly understood. This study investigated the effect of five different OPA1 pathogenic mutations on the energetic efficiency and mitochondrial network dynamics of skin fibroblasts from patients. Although DOA fibroblasts maintained their ATP levels and grew in galactose medium, i.e. under forced oxidative metabolism, a significant impairment in mitochondrial ATP synthesis driven by complex I substrates was found. Furthermore, balloon-like structures in the mitochondrial reticulum were observed in galactose medium and mitochondrial fusion was completely inhibited in about 50% of DOA fibroblasts, but not in control cells. Respiratory complex assembly and the expression level of complex I subunits were similar in control and DOA fibroblasts. Co-immunoprecipitation experiments revealed that OPA1 directly interacts with subunits of complexes I, II and III, but not IV and with apoptosis inducing factor. The results disclose a novel link between OPA1, apoptosis inducing factor and the respiratory complexes that may shed some light on the pathogenic mechanism of DOA.
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PMID:OPA1 mutations associated with dominant optic atrophy impair oxidative phosphorylation and mitochondrial fusion. 1822 90

Near-infrared light (NIL) promotes a wide range of biological effects including enhancement of energy production, gene expression and prevention of cell death. This is the first report of the in vivo neuroprotective effects of NIL against optic neuropathy induced by mitochondrial complex I inhibition. Subjects were pigmented rats that received single bilateral intravitreal doses of rotenone, a mitochondrial complex I inhibitor, or rotenone plus one of three different doses of NIL. Treatment effects were evaluated at behavioral, structural and neurochemical levels. Rotenone induced a decrease in visual function, as determined by changes in the dark-adapted illuminance sensitivity threshold, escape latency and rate of successful trials in a two-choice visual task, compared with vehicle-treated controls. Behavioral impairment correlated with a decrease in retinal and visual pathway metabolic activity, retinal nerve fiber layer thickness and ganglion cell layer cell density. These changes were prevented by NIL treatments in a dose-dependent manner. Whole-brain cytochrome oxidase and superoxide dismutase activities were also increased in NIL-treated subjects in a dose-dependent manner, suggesting an in vivo transcranial effect of NIL. In whole-brain membrane isolates, NIL prevented the rotenone-induced decrease in cell respiration. The results show that NIL treatment can effectively prevent the neurotoxic effects of rotenone and that it might be used in the treatment of neurodegenerative disorders associated with mitochondrial dysfunction.
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PMID:Neuroprotective effects of near-infrared light in an in vivo model of mitochondrial optic neuropathy. 1907 24

We describe a patient with myopathy, sensorimotor neuropathy, hypogonadism, and infertility with abnormal sperm mobility and morphology. Analysis of the deltoid muscle DNA revealed a G to A change at nt 1102 in the twinkle gene and multiple mitochondrial DNA deletions. Histochemistry revealed "ragged-red" fibers and many cytochrome-c oxidase negative fibers (32%) that lacked the mitochondrial encoded respiratory chain subunits I and II and the nuclear encoded subunit VIc. Respiratory chain enzyme analysis showed severe deficiency of complex I, III, and IV. This patient has no documented family history of progressive external ophthalmoplegia, which suggests either a sporadic or autosomal-recessive syndrome. This case is a novel phenotype for twinkle gene mutations and multiple mitochondrial DNA deletion syndromes, as these syndromes generally follow an autosomal-dominant inheritance pattern.
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PMID:A novel clinical phenotype of myopathy, sensorimotor neuropathy, infertility, and hypogonadism with multiple mitochondrial DNA deletions. 1907 59

Methylene blue (MB) is a diaminophenothiazine with potent antioxidant and unique redox properties that prevent morphologic degenerative changes in the mouse retina induced by rotenone, a specific mitochondrial complex I inhibitor. This study evaluated pigmented rats to determine whether MB's neuroprotective effects against rotenone-mediated retinal neurotoxicity have functional relevance and whether these effects are mediated by an improvement in neuronal energy metabolism in vivo. Visual function was behaviorally assessed by determining differences in the illuminance sensitivity threshold pre- and post-bilateral intravitreal injection of rotenone (200 microg/kg) or rotenone plus MB (70 microg/kg). Retinal degeneration was morphologically studied using unbiased stereological tools. Changes in histochemically determined cytochrome oxidase activity in the visual pathway were used to evaluate the impact of treatments on neuronal energy metabolism. Rotenone induced a 1.4 log unit increase in the illumination threshold compared to baseline, as well as a 32% decrease in ganglion cell layer cell (GCL) density, and a 56% decrease in GCL layer + nerve fiber layer thickness. Co-administration of MB prevented the changes in visual function and the retinal histopathology. Furthermore, rotenone induced a functional deafferentation of the visual system, as revealed by decreases in the metabolic activity of the retina, superior colliculus, and visual cortex. These metabolic changes were also prevented by MB. The results provided the first demonstration of MB's behavioral and metabolic neuroprotection against optic neuropathy, and implicate MB as a candidate neuroprotective agent with metabolic-enhancing properties that may be used in the treatment of neurodegenerative diseases associated with mitochondrial dysfunction.
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PMID:Methylene blue provides behavioral and metabolic neuroprotection against optic neuropathy. 1938 99

Acute exposure to organophosphates induces a delayed neurodegenerative condition known as organophosphate-induced delayed neuropathy (OPIDN). The mechanism of OPIDN has not been fully understood as it does not involve cholinergic crisis. The present study has been designed to evaluate the role of mitochondrial dysfunctions in the development of OPIDN. OPIDN was induced in rats by administering acute dose of monocrotophos (MCP, 20 mg/kg body weight, orally) or dichlorvos (DDVP, 200 mg/kg body weight, subcutaneously), 15-20 min after treatment with antidotes [atropine (20 mg/kg body weight) and 2-PAM (100 mg/kg body weight) intraperitoneally]. MDA levels were observed to be higher and thiol content was lower in mitochondria from brain regions of OP exposed animals. This was accompanied by decreased activities of the mitochondrial enzymes; NADH dehydrogenase, succinate dehydrogenase, and cytochrome oxidase. In addition, mitochondrial functions assessed by MTT reduction also confirmed mitochondrial dysfunctions following development of OPIDN. The spatial long-term memory evaluated using elevated plus-maze test was observed to be deficit in OPIDN. The results suggest impaired mitochondrial functions as a mechanism involved in the development of organophosphate induced delayed neuropathy.
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PMID:Impaired mitochondrial functions in organophosphate induced delayed neuropathy in rats. 1951 27

The ND4 G11778A mutation is the most common mitochondrial DNA mutation leading to Leber's hereditary optic neuropathy (LHON). Despite considerable clinical evidences, the modifier role of nuclear background and mitochondrial haplotypes in phenotypic manifestation of LHON remains poorly understood. We investigated the effect of these modifiers on bioenergetics in lymphoblastoid cell lines derived from five affected subjects of one Chinese family carrying the G11778A mutation and five Chinese controls. Significant reductions in the activities of complexes I and III were observed in mutant cell lines from the Chinese family, whereas the mutant cell lines from other families carrying the same mutation exhibited only reduced activity of complex I. The reduced activities of complexes I and III caused remarkably higher reductions of ATP synthesis in mutant cell lines from the Chinese family than those from other families. The deficient respiration increased generation of reactive oxygen species. The defect in complex III activity, likely resulting from the mitochondrial haplotype or nuclear gene alteration, worsens mitochondrial dysfunction caused by the G11778A mutation, thereby causing extremely high penetrance and expressivity of optic neuropathy in this Chinese family. Our data provide the first experimental evidence that altered activity of complex III modulates the phenotypic manifestation of LHON-associated G11778A mutation. Thus, our findings may provide new insights into the pathophysiology of LHON.
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PMID:The altered activity of complex III may contribute to the high penetrance of Leber's hereditary optic neuropathy in a Chinese family carrying the ND4 G11778A mutation. 2174 61


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