Biomarker for determining mitochondrial damage in friedreich's ataxia

Abstract

Compositions and methods for screening for a disease or a disorder associated with a deficiency in frataxin in a subject using biomarkers for diseases or disorders associated with a deficiency in frataxin are disclosed. The compositions and methods include determining the acetylation status of mito-chondrial proteins. Also disclosed are methods of detecting progression of a disease or a disorder associated with a deficiency in frataxin in a subject and methods of monitoring effectiveness of a therapy for diseases or disorders associated with a deficiency in frataxin.

What is claimed is: 
     
         1 . A method of screening for a disease or a disorder associated with a deficiency in frataxin in a subject, the method comprising: determining the acetylation status of a mitochondrial protein in a sample tissue; and determining the acetylation status of a mitochondrial protein in a normal tissue, wherein an increase in acetyl-lysine status of the mitochondrial protein in the sample tissue as compared to acetyl-lysine status of the protein in the normal tissue is indicative of the disease or the disorder associated with the deficiency in frataxin. 
     
     
         2 . The method of  claim 1 , wherein the sample tissue and the normal tissue is selected from the group consisting of liver, heart, white blood cells, and neural tissue. 
     
     
         3 . A method of screening for a disease or a disorder associated with a deficiency in frataxin in a subject, the method comprising: determining the mitochondrial NADH level in a sample tissue; and determining the mitochondrial NADH level in a normal tissue, wherein an increase in the NADH level in the sample tissue as compared to the NADH level in the normal tissue is indicative of the disease or the disorder associated with the deficiency in frataxin. 
     
     
         4 . The method of  claim 3 , further comprising determining the NAD +  level in the sample tissue and determining the NAD +  level in the normal tissue. 
     
     
         5 . The method of  claim 4 , further comprising determining the NAD + /NADH ratio in the sample tissue and determining the NAD + /NADH ratio in the normal tissue, wherein a decrease in the NAD + /NADH ratio in the sample tissue as compared to the NAD + /NADH ratio in normal tissue is indicative of a disease or a disorder associated with a deficiency in frataxin. 
     
     
         6 . A kit for measuring levels of mitochondrial protein acetylation comprising an anti-acetyl-lysine-specific antibody and an antibody that specifically binds to a mitochondrial protein. 
     
     
         7 . The kit of  claim 6 , wherein the antibody that specifically binds to a mitochondrial protein is selected from the group consisting of an antibody that specifically binds to NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 (NDUFA9), an antibody that specifically binds to acetyl-CoA synthetase 2 (AceCS2), an antibody that specifically binds to frataxin, an antibody that specifically binds to complex II 30 kDa subunit, an antibody that specifically binds to complex HI Rieske protein, an antibody that specifically binds to NAD-dependent deacetylase sirtuin-3 (SIRT3), an antibody that specifically binds to voltage-dependent anion-selective channel (VDAC), and combinations thereof 
     
     
         8 . The kit of  claim 6  further comprising at least one of a reagent for processing a sample, a reagent for isolating mitochondria, a reagent for measuring mitochondrial protein acetylation, and a reagent for measuring mitochondrial protein acetylation. 
     
     
         9 . A method of detecting progression of a disease or a disorder associated with a deficiency in frataxin in a subject having or suspected of having the disease or the disorder associated with the deficiency in frataxin, the method comprising: measuring mitochondrial protein acetylation in a first chronological sample from the subject; and measuring mitochondrial protein acetylation in a second chronological sample from the subject, wherein an increase in mitochondrial protein acetylation in the second chronological sample as compared to the mitochondrial protein acetylation in the first chronological sample indicates progression of the disease or the disorder. 
     
     
         10 . The method of  claim 9 , wherein the disease or the disorder associated with the deficiency in frataxin is selected from the group consisting of Friedreich's Ataxia, Parkinson's Disease, Alzheimer's Disease, alcoholism, ischemic heart disease, dementia, Huntington's disease, Amyotrophic lateral sclerosis, cytochrome c oxidase deficiency, autosomal dominant progressive external ophthalmoplegia, and Leber's Hereditary Optic Neuropathy. 
     
     
         11 . The method of  claim 9 , further comprising. prior to the measuring step, steps of: collecting the sample from the subject; and isolating mitochondria front the sample. 
     
     
         12 . The method of  claim 9 , wherein the subject is a human. 
     
     
         13 . The method of  claim 9 , wherein mitochondrial protein acetylation is measured utilizing Western blotting with an antibody that detects acetyl-lysine residues. 
     
     
         14 . A method of monitoring effectiveness of a therapy in a subject having or suspected of having a disease or a disorder associated with a deficiency in frataxin, the method comprising: measuring mitochondrial protein acetylation in at least a first chronological sample; administering the therapy; measuring mitochondrial protein acetylation in at least a second chronological sample from the subject, analyzing the mitochondrial protein acetylation in at least the first chronological sample and the mitochondrial protein acetylation in at least the second chronological sample, wherein a decrease in mitochondrial protein acetylation in the second chronological sample as compared to mitochondrial protein acetylation in a first chronological sample indicates effectiveness of the therapy. 
     
     
         15 . The method of  claim 14 , wherein the disease or the disorder associated with the deficiency in frataxin is selected front the group consisting of Friedreich's Ataxia, Parkinson's Disease, Alzheimer's Disease, alcoholism, ischemic heart disease, dementia, Huntington's disease, Amyotrophic lateral sclerosis, cytochrome c oxidase deficiency, autosomal dominant progressive external ophthalmoplegia, and Leber's Hereditary Optic Neuropathy. 
     
     
         16 . A method of screening for agents useful for treating a disease or a disorder associated with a deficiency in frataxin, the method comprising: measuring mitochondrial protein acetylation in a subject having hyperacetylated mitochondrial proteins; administering an agent suspected of modulating protein acetylation to the subject; and measuring mitochondrial protein acetylation after administration of the agent, wherein the agent is considered to be a candidate for treating the disease or the disorder associated with the deficiency in frataxin if the mitochondrial protein acetylation is decreased in the sample after administration of the agent.