Abstract 2451 Lipid profiling of dermal fibroblasts derived from Hermansky-Pudlak Syndrome patients

Hermansky-Pudlak Syndrome (HPS) is a rare autosomal recessive genetic disease characterized by bleeding diathesis, oculocutaneous albinism and a lysosomal storage disease, frequently associated with granulomatous colitis, and pulmonary fibrosis. HPS exhibits locus heterogeneity and 11 subtypes have been described in humans, genes which code for subunits of Biogenesis of Lysosome-Related Organelles Complexes (BLOCS) and the AP-3 adaptor complex. The mechanisms that influence the development of pulmonary fibrosis in the HPS-1, HPS-2 and HPS-4 subtypes are still unknown. A previous study with HPS mouse models, found that HPS-1 mice had an increase in plasma inflammatory lipids, which could lead to atherosclerosis. We hypothesized that HPS-1 and HPS-2 patients may have high levels of lipid species. To test our hypothesis, we performed lipid profiling of cultured dermal fibroblasts cell lines from HPS patients: HPS-1 (GM14609), HPS-2 (GM17890), and Control (GM00037). Lipids were extracted with methanol, methyl tert-butyl ether and chloroform. LC-MS was performed by running in positive ion ESI at the Montana State Mass Spectrometry Facility (MSMSF). Identifications were made in Progenesis, searching LipidBlast, LipidMaps, and a custom Waters database of lipids (MSMSF). Statistical analysis was performed in Metaboanalyst 5.0, normalizing data with log10 transformation and Auto Scaling. A total of 153 lipid species were identified. The most abundant lipid class was Fatty Acyls (32.03%), followed by Glycerophospholipids (16.99%), Sphingolipids (15.69%), Prenol Lipids (12.42%), Polyketides (10.46%), Glycerolipids (7.84%), and Sterol Lipids (4.58%). Partial Least-Squares Discriminant Analysis (PLS-DA) model, using a permutation test (p-value < 0.001), showed that HPS-1 was most different from Control and HPS-2. Comparative analysis between HPS-1 and Control revealed that fatty acyl glycosides and most of the Fatty esters were decreased in HPS-1, while eicosanoids were increased. Glycerophosphates were decreased in HPS-1, as well as Glycerophosphoinositols and most of the Glycerophosphoethanolamines. Meanwhile, oxidized glycerophospholipids and glycerophosphocholines were increased. Most of the Sphingolipids were increased in HPS-1 including several Ceramide species, Sphingoid bases, and Phosphosphingolipids. Isoprenoids were increased in HPS-1 while menaquinone-4 was the only species to be less abundant. Glycerolipids were increased in HPS-1 including Gingerglycolipid A, while Gingerglycolipid B was decreased. Sterol Lipids were increased in HPS-1, while 5alpha-hydroxycholesterol was decreased. The dissimilarity in lipid abundances in HPS-1 vs Control showed a cellular accumulation of specific lipid species in HPS-1 patients, which suggests that HPS-1 patients could have their lipid metabolism and/or trafficking impaired. Cellular accumulation of lipids could influence many biological processes such as inflammation, signaling pathways, and membrane trafficking, which could influence the pathogenesis of HPS. This research was supported in part by NIMHD RCMI grant U54 MD007600 and NIGMS RISE R25GM061838, P20GM103474 and PR INBRE P20GM103475 grants.