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Mol Cell Proteomics. 2015 Jul;14(7):1734-49. doi: 10.1074/mcp.M114.045609. Epub 2015 Apr 14.

Quantitative Proteomics of Human Fibroblasts with I1061T Mutation in Niemann-Pick C1 (NPC1) Protein Provides Insights into the Disease Pathogenesis.

Author information

1
From the ‡Department of Chemical Physiology.
2
§Department of Cell and Molecular Biology, The Scripps Research Institute, 10550, North Torrey Pines Road, La Jolla, California-92037.
3
§Department of Cell and Molecular Biology, The Scripps Research Institute, 10550, North Torrey Pines Road, La Jolla, California-92037. webalch@scripps.edu jyates@scripps.edu.
4
From the ‡Department of Chemical Physiology, webalch@scripps.edu jyates@scripps.edu.

Abstract

Niemann-Pick type C (NPC) disease is a fatal neurodegenerative disorder characterized by the accumulation of unesterified cholesterol in the late endosomal/lysosomal compartments. Mutations in the NPC1 protein are implicated in 95% of patients with NPC disease. The most prevalent mutation is the missense mutation I1061T that occurs in ∼ 15-20% of the disease alleles. In our study, an isobaric labeling-based quantitative analysis of proteome of NPC1(I1061T) primary fibroblasts when compared with wild-type cells identified 281 differentially expressed proteins based on stringent data analysis criteria. Gene ontology enrichment analysis revealed that these proteins play important roles in diverse cellular processes such as protein maturation, energy metabolism, metabolism of reactive oxygen species, antioxidant activity, steroid metabolism, lipid localization, and apoptosis. The relative expression level of a subset of differentially expressed proteins (TOR4A, DHCR24, CLGN, SOD2, CHORDC1, HSPB7, and GAA) was independently and successfully substantiated by Western blotting. We observed that treating NPC1(I1061T) cells with four classes of seven different compounds that are potential NPC drugs increased the expression level of SOD2 and DHCR24. We have also shown an abnormal accumulation of glycogen in NPC1(I1061T) fibroblasts possibly triggered by defective processing of lysosomal alpha-glucosidase. Our study provides a starting point for future more focused investigations to better understand the mechanisms by which the reported dysregulated proteins triggers the pathological cascade in NPC, and furthermore, their effect upon therapeutic interventions.

PMID:
25873482
PMCID:
PMC4587331
DOI:
10.1074/mcp.M114.045609
[Indexed for MEDLINE]
Free PMC Article

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