After 4?days, cells were re-plated onto a Matrigel (Corning) coated 48-well plate in reprogramming medium, which is essentially Essential 8 Medium without TGF-beta. the WD phenotype in these cells. In addition, -tocopherol (DT) and hydroxypropyl-beta-cyclodextrin (HPBCD) significantly reduced lysosomal size in WD NSCs, and an enhanced effect was observed in DT/HPBCD combination therapy. Conclusion The results demonstrate that these WD NSCs are valid cell-based disease models with characteristic disease phenotypes that can be used to evaluate drug efficacy and screen compounds. DT and HPBCD both reduce LysoTracker dye staining in WD cells. The cells may be used to further dissect the pathology of WD, evaluate compound efficacy, and serve as a platform for high-throughput drug screening to identify new compounds for therapeutic development. Electronic supplementary material The online version of this article (doi:10.1186/s13023-017-0670-9) contains supplementary material, which is available to authorized users. Keywords: Wolman disease, Lysosomal storage disease, Induced pluripotent stem cells, Neural stem cells, Cell-based disease model Background Wolman disease is usually a rare lysosomal storage disorder with an incidence rate of less than 1 in 100,000 births . WD is usually caused by mutations in the gene encoding lysosomal acid lipase (LAL), which results in nonfunctional levels of LAL activity. This leads to the accumulation of triglycerides (TG) and cholesteryl esters (CE) in the lysosomes of many cells and tissues . Clinical manifestations include adrenal calcification, hepatosplenomegaly, and enlarged lymph nodes . These organ and tissue enlargements are due to the accumulation of TG and CE, which may Letrozole also occur in the intestine and central nervous system [4C6]. Typical life expectancy of patients without treatment is usually less than one year of age, with death due to multi-organ failure. Complications of WD are thought to Letrozole be related to malabsorption. Parenteral hyperalimentation has been shown to slow patient deterioration but not cure the disease . Hematopoietic stem cell transplantation Letrozole has been moderately successful for treating WD, but the procedure remains risky [8, 9]. Enzyme replacement therapy (ERT)with sebelipase alfa (KANUMA?)has recently been approved for treating WD [10, 11]. While ERT has reduced abdominal distention, hepatosplenomegaly, vomiting and diarrhea, and improved survival and weight gain, the long term effects of ERT for WD have yet to be evaluated . Small molecule therapies have several advantages over recombinant enzymesincluding lower production costs, more convenient administration, and the ability to penetrate the blood brain barrier. Therefore, the discovery and development of small molecule drugs might improve therapeutic efficacy and long term outcomes. Recent advances in induced pluripotent stem cells (iPSCs) technology has enabled the generation of cell-based disease models derived from patient iPSCs. Several such cell-based models have been described for lysosomal storage diseases including Gaucher disease, Niemann Pick disease type A (NPA), Niemann Pick disease type C Letrozole (NPC), and Pompe disease . These models exhibit the disease phenotypes in cell culture systems and can be used to evaluate drug efficacy. In this study, we have generated four iPS cell lines from two WD patient fibroblasts. We subsequently generated neural stem cells (NSCs) from these WD iPSCs and found both lysosomal enlargement and neutral lipid accumulation in these WD NSCs. Using this cell-based WD model, we then evaluated the pharmacological effects of -tocopherol (DT) and hydroxypropyl-beta-cyclodextrin (HPBCD), which have been shown to reduce cholesterol storage in NPC cells [14, 15]. The results demonstrate that this Letrozole cell-based WD model can PRPH2 be used for evaluating lead compounds and for compound screening in drug development. Methods Materials CELLstart CTS substrate (#A1014201), GlutaMAX (#25030081), Nile red (#N-1142), LysoTracker Red DND-99 (#L-7528), Hoechst 33,342 trihydrochloride (#H3570), Neural Induction Medium (#A1647081), Essential 8 Medium (#A1517001), Human Neural Stem Cell Immunocytochemistry Kit (#A24354), StartingBlock BSA (#37579), TrypLE Express (#12605C036), Oct4 antibody (#A13998), AlexaFluor 488 Donkey anti-mouse antibody (#A21202), AlexaFluor 594 Donkey anti-rabbit antibody (#A21207), and AlexaFluor 595 Donkey anti-goat antibody (#A11058), Amplex red cholesterol assay kit (#A12216), LIPA monoclonal antibody clone 9G7F12,7G6D7 (#MA5C15278), low density lipoprotein.