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1.
Neurotherapeutics ; 19(3): 994-1006, 2022 04.
Article in English | MEDLINE | ID: mdl-35334081

ABSTRACT

Leigh syndrome (LS) is one of the most common mitochondrial encephalopathy diseases in infants. To date, there is still an absence of effective therapy. Bezafibrate (BEZ), a pan-peroxisome proliferator-activated receptor (PPAR) agonist, ameliorates the phenotype of the mouse model of mitochondrial disease via an unclear mechanism. Here, we applied it to Ndufs4 knockout (KO) mice, a widely used LS animal model, to observe the therapeutic effects and metabolic changes associated with BEZ treatment to explore the therapeutic strategies for mitochondrial diseases. Administration of BEZ significantly enhances survival and attenuates disease progression in Ndufs4 KO mice. Decreased oxidative stress and stunted growth were also observed. As a PPAR agonist, we did not find mitochondrial biogenesis or enhanced metabolism upon BEZ treatment. On the contrary, mice with dietary BEZ showed daily torpor bouts and lower metabolic rates. We speculate that activating energy-saving metabolism in mice may be associated with the therapeutic effects of BEZ, but the exact mechanism of action requires further study.


Subject(s)
Bezafibrate , Mitochondrial Encephalomyopathies , Torpor , Animals , Bezafibrate/pharmacology , Bezafibrate/therapeutic use , Disease Models, Animal , Electron Transport Complex I/genetics , Electron Transport Complex I/metabolism , Hypoglycemic Agents , Mice , Mice, Knockout , Mitochondrial Encephalomyopathies/drug therapy , Peroxisome Proliferator-Activated Receptors/agonists , Peroxisome Proliferator-Activated Receptors/genetics , Peroxisome Proliferator-Activated Receptors/metabolism
2.
JCI Insight ; 5(21)2020 11 05.
Article in English | MEDLINE | ID: mdl-33148885

ABSTRACT

Complex I (also known as NADH-ubiquinone oxidoreductase) deficiency is the most frequent mitochondrial disorder present in childhood. NADH-ubiquinone oxidoreductase iron-sulfur protein 3 (NDUFS3) is a catalytic subunit of the mitochondrial complex I; NDUFS3 is conserved from bacteria and essential for complex I function. Mutations affecting complex I, including in the Ndufs3 gene, cause fatal neurodegenerative diseases, such as Leigh syndrome. No treatment is available for these conditions. We developed and performed a detailed molecular characterization of a neuron-specific Ndufs3 conditional KO mouse model. We showed that deletion of Ndufs3 in forebrain neurons reduced complex I activity, altered brain energy metabolism, and increased locomotor activity with impaired motor coordination, balance, and stereotyped behavior. Metabolomics analyses showed an increase of glycolysis intermediates, suggesting an adaptive response to the complex I defect. Administration of metformin to these mice delayed the onset of the neurological symptoms but not of neuronal loss. This improvement was likely related to enhancement of glucose uptake and utilization, which are known effects of metformin in the brain. Despite reports that metformin inhibits complex I activity, our findings did not show worsening a complex I defect nor increases in lactic acid, suggesting that metformin should be further evaluated for use in patients with mitochondrial encephalopathies.


Subject(s)
Electron Transport Complex I/deficiency , Metformin/pharmacology , Mitochondrial Diseases/complications , Mitochondrial Encephalomyopathies/drug therapy , NADH Dehydrogenase/physiology , Neurons/drug effects , Animals , Energy Metabolism , Female , Glycolysis , Hypoglycemic Agents/pharmacology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mitochondrial Encephalomyopathies/etiology , Mitochondrial Encephalomyopathies/metabolism , Mitochondrial Encephalomyopathies/pathology , Neurons/metabolism , Neurons/pathology
3.
EBioMedicine ; 42: 511-523, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30898651

ABSTRACT

BACKGROUND: The vast majority of mitochondrial disorders have limited the clinical management to palliative care. Rapamycin has emerged as a potential therapeutic drug for mitochondrial diseases since it has shown therapeutic benefits in a few mouse models of mitochondrial disorders. However, the underlying therapeutic mechanism is unclear, the minimal effective dose needs to be defined and whether this therapy can be generally used is unknown. METHODS: We have evaluated whether low and high doses of rapamycin administration may result in therapeutic effects in a mouse model (Coq9R239X) of mitochondrial encephalopathy due to CoQ deficiency. The evaluation involved phenotypic, molecular, image (histopathology and MRI), metabolomics, transcriptomics and bioenergetics analyses. FINDINGS: Low dose of rapamycin induces metabolic changes in liver and transcriptomics modifications in midbrain. The high dose of rapamycin induces further changes in the transcriptomics profile in midbrain due to the general inhibition of mTORC1. However, neither low nor high dose of rapamycin were able to improve the mitochondrial bioenergetics, the brain injuries and the phenotypic characteristics of Coq9R239X mice, resulting in the lack of efficacy for increasing the survival. INTERPRETATION: These results may be due to the lack of microgliosis-derived neuroinflammation, the limitation to induce autophagy, or the need of a functional CoQ-junction. Therefore, the translation of rapamycin therapy into the clinic for patients with mitochondrial disorders requires, at least, the consideration of the particularities of each mitochondrial disease. FUND: Supported by the grants from "Fundación Isabel Gemio - Federación Española de Enfermedades Neuromusculares - Federación FEDER" (TSR-1), the NIH (P01HD080642) and the ERC (Stg-337327).


Subject(s)
Mitochondrial Diseases/drug therapy , Sirolimus/therapeutic use , Animals , Autophagy , Cell Respiration/drug effects , Cell Respiration/genetics , Disease Models, Animal , Gene Expression Profiling , Humans , Metabolomics/methods , Mice , Mitochondria/drug effects , Mitochondria/genetics , Mitochondria/metabolism , Mitochondrial Diseases/diagnosis , Mitochondrial Diseases/etiology , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/genetics , Mitochondrial Encephalomyopathies/metabolism , Phenotype , Sirolimus/administration & dosage , Sirolimus/adverse effects , Sirolimus/pharmacokinetics , Treatment Outcome , Ubiquinone/analogs & derivatives , Ubiquinone/genetics , Ubiquinone/metabolism
4.
Chin Med J (Engl) ; 132(3): 269-274, 2019 Feb 05.
Article in English | MEDLINE | ID: mdl-30681492

ABSTRACT

BACKGROUND: Studies on the relationship between antiepileptic drug (AED) administration and clinical outcomes in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) remain scarce. Levetiracetam (LEV) is an AED that is neuroprotective in various neurologic disorders. This study aimed to determine the impact of LEV on the outcome of MELAS. METHODS: A retrospective, single-center study was performed based on a large cohort of patients with MELAS with a history of seizures (n = 102). Decisions on antiepileptic therapies were made empirically. Patients were followed up for 1 to 8 years (median, 4 years) and divided into 2 groups based on whether LEV was administered (LEV or non-LEV). The modified Rankin scale (mRS) scores and mortality risks were analyzed in all patients. RESULTS: LEV, carbamazepine, benzodiazepines, topiramate, oxcarbazepine, valproate, and lamotrigine were administered in 48, 37, 18, 13, 11, 9, and 9 patients, singly or in combination, respectively. The mean mRS score of the LEV group (n = 48) was lower than that of the non-LEV group (n = 54; mean ±â€Šstandard deviation, 2.79 ±â€Š1.47 vs. 3.83 ±â€Š1.93, P = 0.006) up to the end of the study. Nevertheless, there was no difference in the proportion of subjects without disability (mRS ranging 0-1) between the groups (P = 0.37). The multivariate regressions revealed that LEV treatment was associated with lower mRS scores (odds ratio 0.32, 95% confidence interval [CI] 0.15-0.68, P = 0.003) and mortality rates (hazard ratio 0.24, 95% CI 0.08-0.74, P = 0.013). There was a significant difference in the Kaplan-Meier survival curves between the groups (χ = 4.29, P = 0.04). CONCLUSIONS: The LEV administration is associated with lower mortality in patients with MELAS in this retrospective study. Further laboratory research and prospective cohort studies are needed to confirm whether LEV has neuroprotective effects on patients with mitochondrial diseases.


Subject(s)
Acidosis, Lactic/drug therapy , Acidosis, Lactic/mortality , Anticonvulsants/therapeutic use , Levetiracetam/therapeutic use , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/mortality , Stroke/drug therapy , Stroke/mortality , Adolescent , Carbamazepine/therapeutic use , Child , Child, Preschool , Female , Humans , Lamotrigine/therapeutic use , Levetiracetam/administration & dosage , Male , Oxcarbazepine/therapeutic use , Prospective Studies , Retrospective Studies , Topiramate/therapeutic use , Valproic Acid/therapeutic use
5.
EMBO Mol Med ; 11(1)2019 01.
Article in English | MEDLINE | ID: mdl-30482867

ABSTRACT

Coenzyme Q (CoQ) deficiency has been associated with primary defects in the CoQ biosynthetic pathway or to secondary events. In some cases, the exogenous CoQ supplementation has limited efficacy. In the Coq9R239X mouse model with fatal mitochondrial encephalopathy due to CoQ deficiency, we have tested the therapeutic potential of ß-resorcylic acid (ß-RA), a structural analog of the CoQ precursor 4-hydroxybenzoic acid and the anti-inflammatory salicylic acid. ß-RA noticeably rescued the phenotypic, morphological, and histopathological signs of the encephalopathy, leading to a significant increase in the survival. Those effects were due to the decrease of the levels of demethoxyubiquinone-9 (DMQ9) and the increase of mitochondrial bioenergetics in peripheral tissues. However, neither CoQ biosynthesis nor mitochondrial function changed in the brain after the therapy, suggesting that some endocrine interactions may induce the reduction of the astrogliosis, spongiosis, and the secondary down-regulation of astrocytes-related neuroinflammatory genes. Because the therapeutic outcomes of ß-RA administration were superior to those after CoQ10 supplementation, its use in the clinic should be considered in CoQ deficiencies.


Subject(s)
Hydroxybenzoates/administration & dosage , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/pathology , Neuroprotective Agents/administration & dosage , Ubiquinone/analogs & derivatives , Animals , Brain/pathology , Brain/physiopathology , Disease Models, Animal , Energy Metabolism , Histocytochemistry , Mice , Salicylic Acid/administration & dosage , Survival Analysis , Treatment Outcome , Ubiquinone/analysis , Ubiquinone/deficiency , Ubiquinone/genetics , Ubiquinone/metabolism
6.
Medicine (Baltimore) ; 97(52): e13866, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30593190

ABSTRACT

RATIONALE: Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are thought to be rarely accompanied by macroangiopathy. We reported a case of MELAS that presented right distal internal carotid arterial (ICA) stenosis and reviewed 12 similar previously reported cases involving intracranial large blood vessels. PATIENT CONCERNS: A 38-year-old man suffered from recurrent stroke-like episodes (SE) such as alternating hemiparesis (right lesion 3 years ago and current left lesion), cortical blindness and seizure for 3 years, and was previously misdiagnosed as cerebral infarction. Magnetic Resonance Angiography (MRA) and Digital Subtraction Angiography (DSA) revealed right distal ICA stenosis and sparse cortex blood vessels, which were related to the previous SE. DIAGNOSES: He was diagnosed by genetic screening (a mitochondrial DNA A3243G point mutation) and presence of high lactic acidosis (4.03 mmol/L), which rose to 7.8 mmol/L after exercise. INTERVENTION: The patient received Coenzyme Q10, vitamin C, L-arginine for 2 weeks and valproic acid sodium (400 mg bid) to prevent seizures till now. OUTCOMES: He is currently less active and intelligent than his peers, with occasional seizures, and needs family care. LESSONS: Till date, there are 12 reported cases of MELAS combined with major cerebral arteries abnormalities including stenosis, dissection, occlusion, reversible vasoconstriction, aneurysms, and atherosclerosis. Hence, macroangiopathy in MELAS is not very rare. There is correlation between the affected vessels and the lesions in some cases, but not in others, which may increase the misdiagnosis rate. Hence, mitochondrial diseases cannot be excluded due to concurrent macroangiopathic lesions.


Subject(s)
Acidosis, Lactic/complications , Carotid Stenosis/complications , MELAS Syndrome/complications , Mitochondrial Encephalomyopathies/complications , Adult , Arginine/therapeutic use , Ascorbic Acid/therapeutic use , Carotid Stenosis/drug therapy , Humans , MELAS Syndrome/drug therapy , Male , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/genetics , Point Mutation , Ubiquinone/analogs & derivatives , Ubiquinone/therapeutic use , Valproic Acid/therapeutic use
7.
J Int Adv Otol ; 14(1): 157-160, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29460827

ABSTRACT

Cases of dizziness caused by multiple sclerosis are commonly reported, but those caused by mitochondrial encephalomyopathy have been rarely reported. Particularly, the description of eye nystagmography (ENG) using caloric and optokinetic nystagmus tests has not been reported to date. We encountered the case of a 40-year-old woman with mitochondrial encephalomyopathy who visited us with the chief complaint of dizziness. At first, we considered multiple sclerosis based on the magnetic resonance imaging (MRI) findings and dizziness. Repeated attacks of dizziness and serum lactic acid levels suggested mitochondrial encephalomyopathy. A muscle biopsy confirmed the diagnosis. ENG findings suggested central vestibular disorder of the cerebellum and brainstem. This case suggests that we should not rule out the differential diagnosis of a very rare mitochondrial encephalomyopathy in patients who experience dizziness with MRI findings indicative of multiple sclerosis.


Subject(s)
Dizziness/etiology , Mitochondrial Encephalomyopathies/diagnostic imaging , Ubiquinone/analogs & derivatives , Administration, Oral , Adult , Biopsy , Caloric Tests/methods , Diagnosis, Differential , Dizziness/diagnosis , Dizziness/rehabilitation , Female , Humans , Lactic Acid/blood , Magnetic Resonance Imaging/methods , Mitochondrial Encephalomyopathies/complications , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/pathology , Muscles/pathology , Saccades , Treatment Outcome , Ubiquinone/administration & dosage , Ubiquinone/therapeutic use , Vitamins/therapeutic use
8.
EBioMedicine ; 17: 75-87, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28229909

ABSTRACT

Mice with the hypomorphic AIF-Harlequin mutation exhibit a highly heterogeneous mitochondriopathy that mostly affects respiratory chain complex I, causing a cerebral pathology that resembles that found in patients with AIF loss-of-function mutations. Here we describe that the antidiabetic drug pioglitazone (PIO) can improve the phenotype of a mouse Harlequin (Hq) subgroup, presumably due to an inhibition of glycolysis that causes an increase in blood glucose levels. This glycolysis-inhibitory PIO effect was observed in cultured astrocytes from Hq mice, as well as in human skin fibroblasts from patients with AIF mutation. Glycolysis inhibition by PIO resulted from direct competitive inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Moreover, GAPDH protein levels were reduced in the cerebellum and in the muscle from Hq mice that exhibited an improved phenotype upon PIO treatment. Altogether, our results suggest that excessive glycolysis participates to the pathogenesis of mitochondriopathies and that pharmacological inhibition of glycolysis may have beneficial effects in this condition.


Subject(s)
Apoptosis Inducing Factor/genetics , Glycolysis , Hypoglycemic Agents/pharmacology , Mitochondrial Encephalomyopathies/drug therapy , Thiazolidinediones/pharmacology , Animals , Apoptosis Inducing Factor/deficiency , Apoptosis Inducing Factor/metabolism , Cells, Cultured , Cerebellum/metabolism , Female , Fibroblasts/metabolism , Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+)/metabolism , Humans , Hypoglycemic Agents/therapeutic use , Male , Mice , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondrial Encephalomyopathies/genetics , Mitochondrial Encephalomyopathies/metabolism , Muscle, Skeletal/metabolism , Pioglitazone , Thiazolidinediones/therapeutic use
9.
Neuropharmacology ; 117: 74-84, 2017 05 01.
Article in English | MEDLINE | ID: mdl-28161373

ABSTRACT

Mitochondrial encephalopathies are fatal, infantile neurodegenerative disorders caused by a deficit of mitochondrial functioning, for which there is urgent need to identify efficacious pharmacological treatments. Recent evidence shows that rapamycin administered both intraperitoneally or in the diet delays disease onset and enhances survival in the Ndufs4 null mouse model of mitochondrial encephalopathy. To delineate the clinical translatability of rapamycin in treatment of mitochondrial encephalopathy, we evaluated the drug's effects on disease evolution and mitochondrial parameters adopting treatment paradigms with fixed daily, oral doses starting at symptom onset in Ndufs4 knockout mice. Molecular mechanisms responsible for the pharmacodynamic effects of rapamycin were also evaluated. We found that rapamycin did not affect disease development at clinically-relevant doses (0.5 mg kg-1). Conversely, an oral dose previously adopted for intraperitoneal administration (8 mg kg-1) delayed development of neurological symptoms and increased median survival by 25%. Neurological improvement and lifespan were not further increased when the dose raised to 20 mg kg-1. Notably, rapamycin at 8 mg kg-1 did not affect the reduced expression of respiratory complex subunits, as well as mitochondrial number and mtDNA content. This treatment regimen however significantly ameliorated architecture of mitochondria cristae in motor cortex and cerebellum. However, reduction of mTOR activity by rapamycin was not consistently found within the brain of knockout mice. Overall, data show the ability of rapamycin to improve ultrastructure of dysfunctional mitochondria and corroborate its therapeutic potential in mitochondrial disorders. The non-clinical standard doses required, however, raise concerns about its rapid and safe clinical transferability.


Subject(s)
Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/pathology , Sirolimus/therapeutic use , Administration, Oral , Animals , Cerebellum/metabolism , Cerebellum/pathology , DNA, Mitochondrial/metabolism , Disease Progression , Dose-Response Relationship, Drug , Electron Transport Chain Complex Proteins/metabolism , Electron Transport Complex I/genetics , Female , Male , Mice , Mice, Knockout , Mitochondria/ultrastructure , Motor Cortex/metabolism , Motor Cortex/pathology , Muscle, Skeletal/metabolism , Sirolimus/administration & dosage , Sirolimus/blood , Sirolimus/pharmacokinetics , Survival Analysis , TOR Serine-Threonine Kinases/metabolism
10.
Neurotherapeutics ; 11(3): 651-64, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24935635

ABSTRACT

Mitochondrial disorders are deadly childhood diseases for which therapeutic remedies are an unmet need. Given that genetic suppression of the nuclear enzyme poly (adenine diphosphate-ribose) polymerase(PARP)-1 improves mitochondrial functioning, we investigated whether pharmacological inhibition of the enzyme affords protection in a mouse model of a mitochondrial disorder. We used mice lacking the Ndufs4 subunit of the respiratory complex I (Ndufs4 knockout [ KO] mice); these mice undergo progressive encephalopathy and die around postnatal day 50. Mice were treated daily with the potent PARP inhibitor N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-(N,N-dimethylamino)acetamide hydrochloride (PJ34); neurological parameters, PARP activity, and mitochondrial homeostasis were evaluated. We found that mice receiving N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-(N,N-dimethylamino)acetamide hydrochloride from postnatal day 30 to postnatal day 50 show reduced neurological impairment, and increased exploratory activity and motor skills compared with vehicle-treated animals. However, drug treatment did not delay or reduce death. We found no evidence of increased PARP activity within the brain of KO mice compared with heterozygous, healthy controls. Conversely, a 10-day treatment with the PARP inhibitor significantly reduced basal poly(ADP-ribosyl)ation in different organs of the KO mice, including brain, skeletal muscle, liver, pancreas, and spleen. In keeping with the epigenetic role of PARP-1, its inhibition correlated with increased expression of mitochondrial respiratory complex subunits and organelle number. Remarkably, pharmacological targeting of PARP reduced astrogliosis in olfactory bulb and motor cortex, but did not affect neuronal loss of KO mice. In light of the advanced clinical development of PARP inhibitors, these data emphasize their relevance to treatment of mitochondrial respiratory defects.


Subject(s)
Disease Progression , Mitochondria/drug effects , Mitochondria/enzymology , Mitochondrial Encephalomyopathies/enzymology , Phenanthrenes/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors , Poly(ADP-ribose) Polymerases/metabolism , Animals , Brain/drug effects , Mice , Mice, Knockout , Mitochondria/ultrastructure , Mitochondrial Encephalomyopathies/drug therapy , Motor Activity/drug effects , Neuroglia/drug effects , Neuroglia/pathology , Neurons/drug effects , Neurons/pathology , Oxidative Stress/drug effects , Phenanthrenes/therapeutic use , Poly (ADP-Ribose) Polymerase-1 , Poly Adenosine Diphosphate Ribose/metabolism
11.
Biochim Biophys Acta ; 1842(7): 893-901, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24576561

ABSTRACT

Coenzyme Q10 (CoQ10) deficiency (MIM 607426) causes a mitochondrial syndrome with variability in the clinical presentations. Patients with CoQ10 deficiency show inconsistent responses to oral ubiquinone-10 supplementation, with the highest percentage of unsuccessful results in patients with neurological symptoms (encephalopathy, cerebellar ataxia or multisystemic disease). Failure in the ubiquinone-10 treatment may be the result of its poor absorption and bioavailability, which may be improved by using different pharmacological formulations. In a mouse model (Coq9(X/X)) of mitochondrial encephalopathy due to CoQ deficiency, we have evaluated oral supplementation with water-soluble formulations of reduced (ubiquinol-10) and oxidized (ubiquinone-10) forms of CoQ10. Our results show that CoQ10 was increased in all tissues after supplementation with ubiquinone-10 or ubiquinol-10, with the tissue levels of CoQ10 with ubiquinol-10 being higher than with ubiquinone-10. Moreover, only ubiquinol-10 was able to increase the levels of CoQ10 in mitochondria from cerebrum of Coq9(X/X) mice. Consequently, ubiquinol-10 was more efficient than ubiquinone-10 in increasing the animal body weight and CoQ-dependent respiratory chain complex activities, and reducing the vacuolization, astrogliosis and oxidative damage in diencephalon, septum-striatum and, to a lesser extent, in brainstem. These results suggest that water-soluble formulations of ubiquinol-10 may improve the efficacy of CoQ10 therapy in primary and secondary CoQ10 deficiencies, other mitochondrial diseases and neurodegenerative diseases.


Subject(s)
Ataxia/drug therapy , Mitochondria/drug effects , Mitochondrial Diseases/drug therapy , Mitochondrial Encephalomyopathies/drug therapy , Muscle Weakness/drug therapy , Ubiquinone/analogs & derivatives , Ubiquinone/deficiency , Animals , Brain Diseases/drug therapy , Brain Stem/drug effects , Corpus Striatum/drug effects , Electron Transport/drug effects , Mice , Mice, Inbred C57BL , Oxidative Stress/drug effects , Ubiquinone/pharmacology
12.
Comb Chem High Throughput Screen ; 17(3): 253-5, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24409954

ABSTRACT

The Cell screening facility for personalized medicine (CSFPM) at Tel Aviv University in Israel is devoted to screening small molecules libraries for finding new drugs for rare diseases using human cell based models. The main strategy of the facility is based on smartly reducing the size of the compounds collection in similarity clusters and at the same time keeping high diversity of pharmacophores. This strategy allows parallel screening of several patient derived - cells in a personalized screening approach. The tested compounds are repositioned drugs derived from collections of phase III and FDA approved small molecules. In addition, the facility carries screenings using other chemical libraries and toxicological characterizations of nanomaterials.


Subject(s)
Drug Discovery , Drug Evaluation, Preclinical/methods , Rare Diseases/drug therapy , Small Molecule Libraries/pharmacology , Universities/organization & administration , Drug Discovery/organization & administration , Drug Repositioning , Dysautonomia, Familial/drug therapy , Dysautonomia, Familial/pathology , Humans , Intestinal Pseudo-Obstruction/drug therapy , Intestinal Pseudo-Obstruction/pathology , Israel , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/pathology , Muscular Dystrophy, Oculopharyngeal , Ophthalmoplegia/congenital , Precision Medicine/methods , Rare Diseases/pathology
13.
Hum Mol Genet ; 23(9): 2459-67, 2014 May 01.
Article in English | MEDLINE | ID: mdl-24362886

ABSTRACT

Mitochondrial DNA (mtDNA) depletion syndrome (MDS) is characterized by a reduction in mtDNA copy number and consequent mitochondrial dysfunction in affected tissues. A subgroup of MDS is caused by mutations in genes that disrupt deoxyribonucleotide metabolism, which ultimately leads to limited availability of one or several deoxyribonucleoside triphosphates (dNTPs), and subsequent mtDNA depletion. Here, using in vitro experimental approaches (primary cell culture of deoxyguanosine kinase-deficient cells and thymidine-induced mtDNA depletion in culture as a model of mitochondrial neurogastrointestinal encephalomyopathy, MNGIE), we show that supplements of those deoxyribonucleosides (dNs) involved in each biochemical defect (deoxyguanosine or deoxycytidine, dCtd) prevents mtDNA copy number reduction. Similar effects can be obtained by specific inhibition of dN catabolism using tetrahydrouridine (THU; inhibitor of cytidine deaminase) or immucillin H (inhibitor of purine nucleoside phosphorylase). In addition, using an MNGIE animal model, we provide evidence that mitochondrial dNTP content can be modulated in vivo by systemic administration of dCtd or THU. In spite of the severity associated with diseases due to defects in mtDNA replication, there are currently no effective therapeutic options available. Only in the case of MNGIE, allogeneic hematopoietic stem cell transplantation has proven efficient as a long-term therapeutic strategy. We propose increasing cellular availability of the deficient dNTP precursor by direct administration of the dN or inhibition of its catabolism, as a potential treatment for mtDNA depletion syndrome caused by defects in dNTP metabolism.


Subject(s)
DNA, Mitochondrial/genetics , Deoxyribonucleosides/therapeutic use , Intestinal Pseudo-Obstruction/drug therapy , Intestinal Pseudo-Obstruction/metabolism , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/metabolism , Animals , Cells, Cultured , DNA Copy Number Variations/drug effects , DNA Copy Number Variations/genetics , DNA, Mitochondrial/metabolism , Humans , Intestinal Pseudo-Obstruction/genetics , Male , Mice, Knockout , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondrial Encephalomyopathies/genetics , Muscular Dystrophy, Oculopharyngeal , Ophthalmoplegia/congenital
14.
Ital J Pediatr ; 39: 60, 2013 Sep 26.
Article in English | MEDLINE | ID: mdl-24069936

ABSTRACT

Mitochondrial dysfunction manifests in many forms during childhood. There is no effective therapy for the condition; hence symptomatic therapy is the only option. The effect of symptomatic therapy are not well known. We present clinical course, diagnosis and effect of current treatments for six children suffering from mitochondrial encephalomyopathy identified by clinical demonstrations, brain MRI findings and DNA mutations. Two were male and four were female. Their age ranged between 2 and 17 years. Skeletal muscle biopsies were obtained in three and one showed misshaped and enlarged mitochondria under electron microscope. mtDNA mutation frequency was >30%. Five children were diagnosed with MELAS (mitochondrial encephalopathy, lactic acidosis, and strokelike episodes) and one with Leigh's syndrome (LS). All were given cocktail and symptomatic treatments. One of the five MELAS children died from severe complications. The other four MELAS children remain alive; four showed improvement, and one remained unresponsive. Of the four who showed improvement, two do not have any abnormal signs and the other two have some degree of motor developmental delay and myotrophy. The LS child is doing well except for ataxia. Until better therapy such as mitochondrial gene therapy is available, cocktail and symptomatic treatments could at least stabilize these children.


Subject(s)
DNA, Mitochondrial/genetics , MELAS Syndrome/diagnosis , MELAS Syndrome/genetics , Adolescent , Biopsy, Needle , Child , Child, Preschool , DNA Mutational Analysis , Drug Therapy, Combination , Female , Genetic Predisposition to Disease , Humans , Immunohistochemistry , Leigh Disease/diagnosis , Leigh Disease/drug therapy , Leigh Disease/genetics , Leigh Disease/mortality , MELAS Syndrome/drug therapy , MELAS Syndrome/mortality , Magnetic Resonance Imaging/methods , Male , Mitochondrial Encephalomyopathies/diagnosis , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/genetics , Neuroimaging/methods , Polymerase Chain Reaction/methods , Polymorphism, Genetic , Prognosis , Retrospective Studies , Risk Assessment , Sampling Studies , Severity of Illness Index , Survival Rate
16.
JAMA Neurol ; 70(9): 1177-9, 2013 Sep 01.
Article in English | MEDLINE | ID: mdl-23836383

ABSTRACT

IMPORTANCE: Mendelian forms of complex I deficiency are usually associated with fatal infantile encephalomyopathy. Application of "MitoExome" sequencing (deep sequencing of the entire mitochondrial genome and the coding exons of >1000 nuclear genes encoding the mitochondrial proteome) allowed us to reveal an unusual clinical variant of complex I deficiency due to a novel homozygous mutation in ACAD9. The patient had an infantile-onset but slowly progressive encephalomyopathy and responded favorably to riboflavin therapy. OBSERVATION: A 13-year-old boy had exercise intolerance, weakness, and mild psychomotor delay. Muscle histochemistry showed mitochondrial proliferation, and biochemical analysis revealed severe complex I deficiency (15% of normal). The level of complex I holoprotein was reduced as determined by use of Western blot both in muscle (54%) and in fibroblasts (57%). CONCLUSIONS AND RELEVANCE: The clinical presentation of complex I deficiency due ACAD9 mutations spans from fatal infantile encephalocardiomyopathy to mild encephalomyopathy. Our data support the notion that ACAD9 functions as a complex I assembly protein. ACAD9 is a flavin adenine dinucleotide-containing flavoprotein, and treatment with riboflavin is advisable.


Subject(s)
Mitochondria/genetics , Mitochondrial Encephalomyopathies/genetics , Muscle, Skeletal/pathology , Mutation/genetics , Riboflavin/therapeutic use , Adolescent , DNA, Mitochondrial/genetics , DNA, Mitochondrial/metabolism , Genetic Predisposition to Disease , Homozygote , Humans , Male , Mitochondria/metabolism , Mitochondrial Encephalomyopathies/diagnosis , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/metabolism , Muscle, Skeletal/metabolism , Treatment Outcome
17.
Mol Genet Metab ; 109(2): 208-14, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23583222

ABSTRACT

BACKGROUND: Genetically defined Leigh syndrome (LS) is a rare, fatal inherited neurodegenerative disorder that predominantly affects children. Although mitochondrial dysfunction has clearly been associated with oxidative stress, few studies have specifically examined Leigh syndrome patients' blood glutathione levels. In this study, we analyzed the balance between oxidized and reduced glutathione in lymphocytes of 10 patients with genetically confirmed LS and monitored the effects of glutathione status following 6 months of treatment with EPI-743, a novel redox therapeutic. METHODS: Lymphocytes were obtained from blood samples of 10 children with a genetically confirmed diagnosis of LS and in 20 healthy subjects. Total, reduced, oxidized and protein-bound glutathione levels were determined by HPLC analysis. Erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities were measured by spectrophotometric assays. Plasma total thiols, carbonyl contents and malondialdehyde were assessed by spectrophotometric and fluorometric assays. RESULTS: A significant impairment of all glutathione forms was detected in patients, including a profound decrease of total and reduced glutathione (GSH) associated with high levels of all oxidized glutathione forms (GSSG+GS-Pro; OX). These findings negatively correlated with the glutathione peroxidase activity, which underwent a significant decrease in patients. After treatment with EPI-743, all patients showed a significant increase in reduced glutathione levels and 96% decrease of OX/GSH ratio. CONCLUSIONS: The data presented here strongly support glutathione as a "redox blood signature" in mitochondrial disorders and its use as a clinical trial endpoint in the development of mitochondrial disease therapies.


Subject(s)
Glutathione/blood , Mitochondrial Encephalomyopathies/blood , Ubiquinone/analogs & derivatives , Adolescent , Case-Control Studies , Child , Child, Preschool , Erythrocytes/enzymology , Glutathione Peroxidase/metabolism , Humans , Infant , Malondialdehyde/blood , Mitochondrial Encephalomyopathies/drug therapy , Oxidation-Reduction , Superoxide Dismutase/metabolism , Treatment Outcome , Ubiquinone/therapeutic use
18.
Toxicol Sci ; 131(1): 311-24, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22977166

ABSTRACT

Erythrocyte-encapsulated thymidine phosphorylase (EE-TP) is currently under development as an enzyme replacement therapy for mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), an autosomal recessive disorder caused by a deficiency of thymidine phosphorylase. The rationale for the development of EE-TP is based on the pathologically elevated metabolites (thymidine and deoxyuridine) being able to freely diffuse across the erythrocyte membrane where the encapsulated enzyme catalyses their metabolism to the normal products. The systemic toxic potential of EE-TP was assessed when administered intermittently by iv bolus injection to BALB/c mice and Beagle dogs for 4 weeks. The studies consisted of one control group receiving sham-loaded erythrocytes twice weekly and two treated groups, one dosed once every 2 weeks and the other dosed twice per week. The administration of EE-TP to BALB/c mice resulted in thrombi/emboli in the lungs and spleen enlargement. These findings were also seen in the control group, and there was no relationship to the number of doses administered. In the dog, transient clinical signs were associated with EE-TP administration, suggestive of an immune-based reaction. Specific antithymidine phosphorylase antibodies were detected in two dogs and in a greater proportion of mice treated once every 2 weeks. Nonspecific antibodies were detected in all EE-TP-treated animals. In conclusion, these studies do not reveal serious toxicities that would preclude a clinical trial of EE-TP in patients with MNGIE, but caution should be taken for infusion-related reactions that may be related to the production of nonspecific antibodies or a cell-based immune response.


Subject(s)
Drug Carriers , Enzyme Replacement Therapy , Erythrocytes , Intestinal Pseudo-Obstruction/drug therapy , Mitochondrial Encephalomyopathies/drug therapy , Thymidine Phosphorylase/toxicity , Toxicity Tests/methods , Animals , Blood Transfusion, Autologous , Dogs , Drug Carriers/chemistry , Drug Evaluation, Preclinical , Erythrocyte Transfusion , Erythrocytes/chemistry , Intestinal Pseudo-Obstruction/enzymology , Mice , Mice, Inbred BALB C , Mitochondrial Encephalomyopathies/enzymology , Muscular Dystrophy, Oculopharyngeal , Ophthalmoplegia/congenital , Thymidine Phosphorylase/administration & dosage
19.
J Paediatr Child Health ; 48(3): E96-7, 2012 Mar.
Article in English | MEDLINE | ID: mdl-21535285

ABSTRACT

Arginine hydrochloride is used in the evaluation of short stature and in the management of urea cycle disorders. In recent times, it has been used in the treatment of stroke-like episodes of MELAS (mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes). We want to highlight the need for good intravenous access and monitoring the drip site to prevent extravasation injuries that can be caused by arginine, which is a hyperosmolar solution.


Subject(s)
Arginine/adverse effects , Extravasation of Diagnostic and Therapeutic Materials , Necrosis/chemically induced , Skin/physiopathology , Acidosis, Lactic/drug therapy , Arginine/administration & dosage , Child , Humans , Male , Mitochondrial Encephalomyopathies/drug therapy , Outcome Assessment, Health Care , Queensland , Seizures/drug therapy
20.
Rev. esp. anestesiol. reanim ; 58(9): 585-587, nov. 2011.
Article in Spanish | IBECS | ID: ibc-93713

ABSTRACT

El síndrome de MNGIE (encefalopatía mitocondrial neuro-gastrointestinal) es una miopatía mitocondrial caracterizada clínicamente por leucoencefalopatía, neuropatía periférica, ptosis, oftalmoparesia y alteraciones en la motilidad gastrointestinal. Las miopatías mitocondriales son enfermedades infrecuentes con poca experiencia en su manejo anestésico. Describimos el procedimiento anestésico ante una intervención de urgencia por megacolon en una mujer de 26 años que presentaba síndrome de MNGIE. Se monitorizó con ECG, presión arterial invasiva, SpO2, EtCO2, espirometría, bloqueo neuromuscular y profundidad anestésica (entropía). Se realizó inducción de secuencia rápida con midazolam, fentanilo y propofol utilizando rocuronio como alternativa a succinilcolina y el mantenimiento con anestesia intravenosa con propofol, sin precisar repetir la dosis de bloqueante neuromuscular. No se apreciaron problemas intraoperatorios, procediendo a la extubación a las 2 horas de la llegada a la unidad de reanimación, tras comprobar el grado de bloqueo y sin necesidad de revertir el mismo(AU)


Mitochondrial neurogastrointestinal encephalopathy (MNGIE) is characterized by leukoencephalopathy, peripheral neuropathy, ptosis, ophthalmoplegia, and gastrointestinal dysmotility. Mitochondrial myopathies are rare diseases and little is known of how to manage them when the patient requires anesthesia. We describe the anesthetic procedure used during emergency surgery for megacolon in a 26-year-old woman with MNGIE. Variables monitored were electrocardiogram, invasive arterial pressure, oxygen saturation by pulse oximetry, end-tidal carbon dioxide pressure, neuromuscular block, and depth of anesthesia (entropy). Rapid sequence induction was accomplished with midazolam, fentanyl, propofol, and rocuronium as an alternative to succinylcholine. Anesthesia was maintained with intravenous propofol; a second dose of the neuromuscular blocker was not required. No intraoperative problems developed and extubation was possible 2 hours after arrival in the postoperative critical care unit, once we had checked the level of block to confirm that reversion was not required(AU)


Subject(s)
Humans , Female , Adult , Mitochondrial Encephalomyopathies/drug therapy , Mitochondrial Encephalomyopathies/rehabilitation , Leukoencephalopathies/complications , Leukoencephalopathies/diagnosis , Megacolon/complications , Neuromuscular Blocking Agents/administration & dosage , Neuromuscular Blocking Agents/therapeutic use , Anesthesia, Intravenous/methods , Anesthesia, Intravenous , Arterial Pressure , Arterial Pressure/physiology , Spirometry/methods , Spirometry , Midazolam/therapeutic use , Fentanyl/therapeutic use , Propofol/therapeutic use , Succinylcholine/therapeutic use
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