PROJECT SUMMARY/ABSTRACT Niemann-Pick disease, type C1 (NPC1), is an autosomal recessive, neurovisceral disorder, and patients typically succumb to complications of the disease in the early adulthood years. The clinical phenotype of NPC1 is broad including both central nervous system and peripheral dysfunction and currently there is no FDA- approved therapy. The enclosed proposal seeks to develop and understand the mechanism of action of a new class of peptides to ameliorate cholesterol storage and associated phenotypes of NPC1. Our central approach is to address the biochemical deficits upstream of the NPC1 protein. First, we will understand how defined protein and lipid biomarkers respond to peptide treatment. Second, we will perform a DMPK study and investigate lifespan extension with treatment. Third, we will investigate the mechanism of action by which these peptides reduce cholesterol storage. To carry out the proposed project, we will leverage our expertise in mass spectrometry, biochemistry and molecular biology techniques.