Niemann-Pick type C (NPC) disease is a cholesterol-glycosphingolipid (GSL) lysosomal storage disorder caused most commonly by defects in NPC1, a transmembrane protein believed critical in retroendocytic trafficking of substrates from lysosomes. Most affected children appear normal at birth, develop progressive neurological disease in their early years and die in their second decade. We have pioneered the development of two compounds for this disorder. The first, N-butyldeoxynojirimycin (NB-DNJ) or miglustat is a documented inhibitor of GSL synthesis, whereas the second, hydroxypropyl ?-cyclodextrin (HPBCD), is an FDA-approved excipient used for drug solublization. Both compounds are efficacious in delaying onset of neurological disease and prolonging life (by 25% and 100%, respectively) in the mouse model of NPC1 disease. Yet neither drug is understood in terms of the precise mechanism responsible for its effectiveness. For miglustat, evidence for sustained reductions in ganglioside storage following oral administration to Npc1 mice is lacking. Similarly, for HPBCD, while both cholesterol and GSL storage are substantially reduced following treatment in Npc1 mice, the mechanism underlying this benefit is completely unknown, and indeed controversy continues even over its ability to cross the blood brain barrier. This proposal will carry out a series of complementary in vivo and in vitro studies employing current and novel reagents and animal models, and quantitative high-resolution imaging, biochemical and genetic evaluations, each directed at treatment mechanisms for NPC disease. Our first two aims are to precisely define HPBCD's mechanism of action in reducing cholesterol/GSL storage in neurons and to critically re-examine and assess miglustat's ability to reduce GSL synthesis as a basis for its beneficial impact on neuron survival.
Our third aim uses an unbiased gene analysis approach to explore the full range of metabolic pathways impacted by each drug. Capitalizing on lessons learned in these aims, new combinatorial treatment strategies will be tested in the fourth aim as a means to substantially improve therapy for children with NPC disease.
Lysosomal storage disorders are a group of about 60 rare; fatal genetic diseases caused by defects in a wide range of proteins associated with the endosomal-lysosomal system. Niemann-Pick type C (NPC) disease is a cholesterol-glycosphingolipid (GSL) storage disorder caused most commonly by defects in NPC1; a transmembrane protein believed critical in retroendocytic trafficking of substrates from lysosomes. Affected children typically appear normal at birth but exhibit progressive neurological decline beginning at 4-6 years of age with death often occurring in the second decade of life. Therapeutic options for NPC disease are very limited; with enzyme replacement; cell-mediated; and gene therapies providing little hope of benefit since the NPC1 protein is not soluble and secreted by cells. Such limitations have driven development of drugs that can limit the build-up of offending substrates in brain and other organs - known as substrate reduction therapy (SRT). We have pioneered the study of two such agents; N- butyldeoxynojirimycin (miglustat) and 2-hydroxypropyl -cyclodextrin (HPBCD); both of which have shown efficacy for NPC disease in animal models. The purpose of this grant is to determine the mechanisms by which these two agents delay clinical disease and increase longevity in the murine model of NPC disease. This goal has now become all the more timely as a clinical trial involving HPBCD for treatment of children with NPC disease is being proposed to the FDA; to begin in 2012. Many of the individuals enrolling in this trial will also be under treatment with miglustat. Understanding the mechanisms of action and possible interactions (e.g.; synergy) of HPBCD and miglustat are of paramount importance. Importantly; given similarities between NPC and other lysosomal diseases; as well as more common neurodegenerative conditions like Alzheimer's; successful treatments emerging here may provide benefit well beyond a single rare disease.
|Boudewyn, Lauren C; Sikora, Jakub; Kuchar, Ladislav et al. (2017) N-butyldeoxynojirimycin delays motor deficits, cerebellar microgliosis, and Purkinje cell loss in a mouse model of mucolipidosis type IV. Neurobiol Dis 105:257-270|
|Davidson, Cristin D; Fishman, Yonatan I; Puskás, István et al. (2016) Efficacy and ototoxicity of different cyclodextrins in Niemann-Pick C disease. Ann Clin Transl Neurol 3:366-80|
|Vite, Charles H; Bagel, Jessica H; Swain, Gary P et al. (2015) Intracisternal cyclodextrin prevents cerebellar dysfunction and Purkinje cell death in feline Niemann-Pick type C1 disease. Sci Transl Med 7:276ra26|
|Praggastis, Maria; Tortelli, Brett; Zhang, Jessie et al. (2015) A murine Niemann-Pick C1 I1061T knock-in model recapitulates the pathological features of the most prevalent human disease allele. J Neurosci 35:8091-106|
|Ottinger, Elizabeth A; Kao, Mark L; Carrillo-Carrasco, Nuria et al. (2014) Collaborative development of 2-hydroxypropyl-?-cyclodextrin for the treatment of Niemann-Pick type C1 disease. Curr Top Med Chem 14:330-9|
|Pontikis, Charles C; Davidson, Cristin D; Walkley, Steven U et al. (2013) Cyclodextrin alleviates neuronal storage of cholesterol in Niemann-Pick C disease without evidence of detectable blood-brain barrier permeability. J Inherit Metab Dis 36:491-8|
|Fan, Martin; Sidhu, Rohini; Fujiwara, Hideji et al. (2013) Identification of Niemann-Pick C1 disease biomarkers through sphingolipid profiling. J Lipid Res 54:2800-14|
|Cluzeau, Celine V M; Watkins-Chow, Dawn E; Fu, Rao et al. (2012) Microarray expression analysis and identification of serum biomarkers for Niemann-Pick disease, type C1. Hum Mol Genet 21:3632-46|
|Stein, Veronika M; Crooks, Alexandra; Ding, Wenge et al. (2012) Miglustat improves purkinje cell survival and alters microglial phenotype in feline Niemann-Pick disease type C. J Neuropathol Exp Neurol 71:434-48|
|Walkley, Steven U; Sikora, Jakub; Micsenyi, Matthew et al. (2010) Lysosomal compromise and brain dysfunction: examining the role of neuroaxonal dystrophy. Biochem Soc Trans 38:1436-41|
Showing the most recent 10 out of 14 publications