In 1984, we described two patients with """"""""Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like Episodes"""""""".1 We proposed the acronym MELAS for this newly described distinctive clinical entity, and speculated about maternal non-Mendelian inheritance, and a mitochondrial DNA (mtDNA) mutation disturbing synthesis of proteins embedded in the respiratory chain. Six years later, Goto and colleagues identified a point mutation in mtDNA (m.3243A>G) of MELAS patients.2 This mutation now accounts for 80% of MELAS cases (commonly referred to as MELAS/3243). For two decades, our team has conducted a long-term longitudinal study of MELAS/3243 patients, establishing a strong foundation in terms of natural history, outcome measures, and biomarkers. However, since there are no clearly validated biomarkers for predicting the risk of conversion, prodromal and mildly symptomatic family relatives continue to live with the uncertainty of converting to the severe MELAS phenotype. This reality emphasizes the need to expand our nascent observations about the natural history of MELAS and the predictive value of brain biomarkers. Our strategies are based on (Specific Aim #1) the need to replicate, using 1H MRSI, our highly promising, preliminary observations of abnormal levels of lactate, NAA, tCr and tCho, in 100 mutation carriers and 30 group-matched healthy control subjects, first at baseline and then again at 2-year follow-up;(Specific Aim #2) the need to measure, using 31P MRSI in synchrony with 1H MRSI, brain levels of (a) phosphocreatine (PCr) to complement and corroborate tCr levels, measured by 1H MRSI, as a marker of cell energetics;b) ATP, to complement and corroborate the 1H MRSI measures of NAA and lactate as indices of mitochondrial dysfunction;c) phosphomonoesters (PME) and phosphodiesters (PDE), to complement and corroborate tCho levels, measured by 1H MRSI, as indices of membrane biosynthesis and turnover, and (d) inorganic phosphate (Pi) as an index of intracellular pH;and (Specific Aim #3) the need to measure temporally concordant levels of metabolite biomarkers in the plasma and urine samples collected from all 130 participants. These three Aims will strengthen our earlier findings of predictive neuroimaging biomarkers, inform us of brain mechanisms underlying metabolic and clinical disturbances, and provide complementary plasma and urine metabolites that, if correlated with the brain biomarkers, will serve as less expensive and more accessible biomarkers predicting risk of conversion to the severe MELAS phenotype.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Program Projects (P01)
Project #
1P01HD080642-01
Application #
8741705
Study Section
Developmental Biology Subcommittee (CHHD)
Project Start
2014-09-30
Project End
2019-05-31
Budget Start
2014-09-30
Budget End
2015-05-31
Support Year
1
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Type
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10032
Joseph, Leroy C; Barca, Emanuele; Subramanyam, Prakash et al. (2016) Inhibition of NAPDH Oxidase 2 (NOX2) Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes. PLoS One 11:e0145750
Barca, E; Musumeci, O; Montagnese, F et al. (2016) Cerebellar ataxia and severe muscle CoQ10 deficiency in a patient with a novel mutation in ADCK3. Clin Genet 90:156-60
Torres-Torronteras, Javier; Cabrera-Pérez, Raquel; Barba, Ignasi et al. (2016) Long-Term Restoration of Thymidine Phosphorylase Function and Nucleoside Homeostasis Using Hematopoietic Gene Therapy in a Murine Model of Mitochondrial Neurogastrointestinal Encephalomyopathy. Hum Gene Ther 27:656-67
Fryer, Robert H; Bain, Jennifer M; De Vivo, Darryl C (2016) Mitochondrial Encephalomyopathy Lactic Acidosis and Stroke-Like Episodes (MELAS): A Case Report and Critical Reappraisal of Treatment Options. Pediatr Neurol 56:59-61
Dalla Rosa, Ilaria; Cámara, Yolanda; Durigon, Romina et al. (2016) MPV17 Loss Causes Deoxynucleotide Insufficiency and Slow DNA Replication in Mitochondria. PLoS Genet 12:e1005779
Cloonan, Suzanne M; Glass, Kimberly; Laucho-Contreras, Maria E et al. (2016) Mitochondrial iron chelation ameliorates cigarette smoke-induced bronchitis and emphysema in mice. Nat Med 22:163-74
Engelstad, Kristin; Sklerov, Miriam; Kriger, Joshua et al. (2016) Attitudes toward prevention of mtDNA-related diseases through oocyte mitochondrial replacement therapy. Hum Reprod 31:1058-65
Barca, Emanuele; Tang, Maoxue; Kleiner, Giulio et al. (2016) CoQ10 Deficiency Is Not a Common Finding in GLUT1 Deficiency Syndrome. JIMD Rep 29:47-52
Sadat, Roa; Barca, Emanuele; Masand, Ruchi et al. (2016) Functional cellular analyses reveal energy metabolism defect and mitochondrial DNA depletion in a case of mitochondrial aconitase deficiency. Mol Genet Metab 118:28-34
Varma, Hemant; Faust, Phyllis L; Iglesias, Alejandro D et al. (2016) Whole exome sequencing identifies a homozygous POLG2 missense variant in an infant with fulminant hepatic failure and mitochondrial DNA depletion. Eur J Med Genet 59:540-5

Showing the most recent 10 out of 26 publications