Untargeted metabolite profiling of sporadic ALS patient fibroblasts: identifying mechanisms of the disease

Weill Medical Coll Of Cornell Univ, New York NY

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Abstract

? DESCRIPTION (provided by applicant): Sporadic amyotrophic lateral sclerosis (sALS) is a devastating neurodegenerative disease in which motor neuron function rapidly degrades. This results in the gradual loss of limb function and respiratory capability, generally leading to respiratory failure and death 2-5 years after diagnosis. The causes of the disease are unknown and no mechanism of disease progression has been described. Due to this major lack of understanding of the disease, therapeutic targets, and therefore effective interventional therapeutics, do not exist. Currently, the only FDA approved drug for ALS is Riluzole, which provides only a 3-6 month average survival increase. Identification of the causes and mechanisms of ALS pathogenesis are essential to developing efficacious therapies to treat the disease. In preliminary data, I have shown that untargeted mass spectrometry of sALS patient-derived skin fibroblast extracts reveals abnormal metabolite abundances that relate to bioenergetics pathways, such as the Krebs cycle. This data supports the hypothesis that metabolic and bioenergetics dysfunction are integral to sALS pathology, which is based on results from the lab of co-mentor (Giovanni Manfredi) that showed bioenergetics abnormalities, including increased mitochondrial membrane potential (MMP), increased oxygen consumption rate (OCR), and increased extracellular acidification rate (ECAR), in the same sALS patient fibroblasts. Along these lines, a number of metabolomics studies of sALS patient plasma and CSF indicate changes in energy-related metabolites. The objective of the proposed project is to perform untargeted metabolite profiling to reveal metabolite abnormalities that are common to sALS patients and to determine metabolic pathways whose dysregulation contributes to the disease. Considering the fact that sALS research has yielded so little information about the mechanism, this focus on small molecule metabolites as a cause of sALS provides a much needed, novel viewpoint from which to study the disease. Untargeted metabolite profiling will be performed on patient fibroblast cell extracts using mass spectrometry. Advanced statistical analysis will identify significant metabolite differences between sALS and control groups. This will be the first project to look at live-cell patient samples and will be the largest, most comprehensive sALS metabolomics study to date. Supplied metabolites will be used to determine if these metabolite abundance abnormalities cause the unusual mitochondrial bioenergetics in sALS described above. Finally, suspected pathways responsible for these abnormalities will be confirmed by heavy isotope tracing experiments using pathway precursors. The metabolite abnormalities identified in this project can potentially be developed into greatly needed biomarkers for early disease diagnosis. This project may also aid in developing effective therapeutics for sALS by providing information about the disease mechanism and by highlighting abnormalities that can be targeted for treatment and drug development.