Global ETD Search

1	Therapeutic strategies for the ganglioside storage diseases Baek, Rena C. January 2008 (has links) The Gangliosidoses, to include GM1 gangliosidosis and Sandhoff disease are a class of incurable lysosomal storage disorders characterized by an abnormal accumulation of gangliosides leading to progressive neurodegeneration and eventually death. GM1 gangliosidosis is caused by a genetic defect in the lysosomal-specific acid β-galactosidase, which results in the massive accumulation of ganglioside GM1 primarily in the central nervous system (CNS). Sandhoff disease (SD) results from a defect in the β-subunit of β- Hexosaminidase A and leads to the accumulation of ganglioside GM2 and its asialo derivative (GA2). As there are no effective therapies for these glycosphingolipid (GSL) storage disorders, I studied substrate reduction therapy (SRT), stem cell therapy, and adeno-associated viral (AAV) gene therapy in neonatal mice as early intervention therapies and were effective in reducing CNS GSL storage. In addition, AAV gene therapy was also evaluated in the adult GM1 gangliosidosis mice. Furthermore, analysis of the brain lipids in mice, cats, and humans with Sandhoff disease revealed that the SD cat model is intermediate between the SD mouse and the SD patient with respect to GM2 and GA2 accumulation. These findings are the first to compare the different therapies and provide valuable information for the translation of mouse studies to clinical trials in patients. / Thesis (PhD) — Boston College, 2008. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology. substrate reduction therapy neural stem cells AAV-mediated gene therapy
2	Novel Therapies and Biochemical Insights for the GM1 and GM2 Gangliosidoses Arthur, Julian January 2011 (has links) Thesis advisor: Thomas N. Seyfried / Gangliosides are glycosphingolipids (GSLs) containing sialic acids that play numerous roles in neuronal maturation, apoptotic signaling, angiogenesis, and cell surface receptor activity. The GM1 and GM2 gangliosidoses are a series of autosomal recessive lysosomal storage disorders (LSDs) characterized by an inability to degrade these lipid molecules. GM1 gangliosidosis is caused by a mutation in the lysosomal hydrolase β-galactosidase, resulting in neuronal storage of ganglioside GM1 and asialo GA1. Tay-Sachs (TS) and Sandhoff Disease (SD) are GM2 gangliosidoses caused by mutations in either the α or β subunits, respectively, of the heterodimeric protein β- hexosaminidase A, resulting in the storage of ganglioside GM2 and asialo GA2. The accumulation of excess ganglioside in the central nervous system leads to abnormal intracellular vacuoles, neuronal loss, demyelination, ataxia, dementia, and premature death. In my studies, I have shown that accumulation of GM1 ganglioside may not coincide with secondary storage of cholesterol, by providing evidence that cholesterol-binding fluorescent molecule filipin reacted to GM1 ganglioside in the absence of cholesterol. In an effort to combat the early-onset gangliosidoses, I have explored the effects of combining Neural Stem Cells (NSCs) with Substrate Reduction Therapy (SRT) in juvenile Sandhoff mice. The analysis showed that SRT was more effective than NSCs in reducing stored GM2 and GA2 in young mice, and no synergy was observed. In adult GM1 gangliosidosis, Tay- Sachs, and Sandhoff mice, Adeno-Associated Viral (AAV) vector gene therapy was used to restore therapeutic levels of wild-type enzyme to the CNS. AAV therapy corrected ganglioside storage and ameliorated myelin-associated lipid loss in all tissues assayed, increasing motor performance and life in effected animals. Lastly, AAV therapy was also successful in a feline model of Sandhoff disease. These results in juvenile and adult model systems point the way towards multiple effective clinical therapies in the near future. / Thesis (PhD) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology. Ganglioside Gene Therapy Lysosome Neurodegeneration Stem Cell Substrate Reduction Therapy
3	Novel Intrinsic and Extrinsic Approaches to Selectively Regulate Glycosphingolipid Metabolism Kamani, Mustafa 08 August 2013 (has links) Glycosphingolipid (GSL) metabolism is a complex process involving proteins and enzymes at distinct locations within the cell. Mammalian GSLs are typically based on glucose or galactose, forming glucosylceramide (GlcCer) and galactosylceramide (GalCer). Most GSLs are derived from GlcCer, which is synthesized on the cytosolic leaflet of the Golgi, while all subsequent GSLs are synthesized on the lumenal side. We have utilized both pharamacological and genetic manipulation approaches to selectively regulate GSL metabolism and better understand its mechanistic details. We have developed analogues of GlcCer and GalCer by substituting the fatty acid moiety with an adamanatane frame. The resulting adamantylGSLs are more water-soluble than their natural counterparts. These analogues selectively interfere with GSL metabolism at particular points within the metabolic pathway. At 40 µM, adaGlcCer prevents synthesis of all GSLs downstream of GlcCer, while also elevating GlcCer levels, by inhibiting lactosylceramide (LacCer) synthase and glucocerebrosidase, respectively. AdaGalCer specifically reduces synthesis of globotriaosylceramide (Gb3) and downstream globo-series GSLs. AdaGalCer also increases Gaucher disease N370S glucocerebrosidase expression, lysosomal localization and activity. AdaGSLs, therefore, have potential as novel therapeutic agents in diseases characterized by GSL anomalies and as tools to study the effects of GSL modulation. Two predominant theories have been developed to explain how GlcCer accesses the Golgi lumen: one involving direct translocation from the cytosolic-to-lumenal leaflet of the Golgi by the ABC transporter P-glycoprotein (P-gp, ABCB1, MDR1), and the other involving retrograde transport of GlcCer by FAPP2 to the ER, followed by entry into the vesicular transport system for Golgi lumenal access. To examine the in vivo involvement of P-gp in GSL metabolism, we generated a knockout model by crossbreeding the Fabry disease mouse with the P-gp knockout mouse. HPLC analyses of tissue Gb3 levels revealed a tissue-specific reduction in MDR1/Fabry mice. TLC analyses, however, did not show such reduction. In addition, we performed a gene knockdown study using siRNA against P-gp and FAPP2. Results show these siRNA to have distinct effects on GSL levels that are cell-type specific. These results give rise to the prospect of unique therapeutic approaches by targeting P-gp or FAPP2 for synthesis inhibition of particular GSL pathways. Sphingolipids Metabolism Lysosomal storage disorders adamantane Glucosylceramide Lactosylceramide P-glycoprotein MDR1 Gaucher disease Fabry disease siRNA Gb2 galabiosylceramide Glycolipids Inhibitors Knockout mouse Crossbreeding Glucosylceramide synthase Lactosylceramide synthase Ganglioside Globo-series Gb3 synthase pharmacological chaperone Glucocerebrosidase Substrate reduction therapy ATP8B1 Cholesterol ABC Transporters P-type ATPase Flippase FAPP2 GLTP Glycosyltransferase Glycolipid analogues ERAD ABCB1 knockdown GM3 and EGFR GM3 and insulin receptor Glycolipid synthesis Glycolipid metabolism enzyme enhancement therapy 0487 0307 0491 0379 0306
4	Novel Intrinsic and Extrinsic Approaches to Selectively Regulate Glycosphingolipid Metabolism Kamani, Mustafa 08 August 2013 (has links) Glycosphingolipid (GSL) metabolism is a complex process involving proteins and enzymes at distinct locations within the cell. Mammalian GSLs are typically based on glucose or galactose, forming glucosylceramide (GlcCer) and galactosylceramide (GalCer). Most GSLs are derived from GlcCer, which is synthesized on the cytosolic leaflet of the Golgi, while all subsequent GSLs are synthesized on the lumenal side. We have utilized both pharamacological and genetic manipulation approaches to selectively regulate GSL metabolism and better understand its mechanistic details. We have developed analogues of GlcCer and GalCer by substituting the fatty acid moiety with an adamanatane frame. The resulting adamantylGSLs are more water-soluble than their natural counterparts. These analogues selectively interfere with GSL metabolism at particular points within the metabolic pathway. At 40 µM, adaGlcCer prevents synthesis of all GSLs downstream of GlcCer, while also elevating GlcCer levels, by inhibiting lactosylceramide (LacCer) synthase and glucocerebrosidase, respectively. AdaGalCer specifically reduces synthesis of globotriaosylceramide (Gb3) and downstream globo-series GSLs. AdaGalCer also increases Gaucher disease N370S glucocerebrosidase expression, lysosomal localization and activity. AdaGSLs, therefore, have potential as novel therapeutic agents in diseases characterized by GSL anomalies and as tools to study the effects of GSL modulation. Two predominant theories have been developed to explain how GlcCer accesses the Golgi lumen: one involving direct translocation from the cytosolic-to-lumenal leaflet of the Golgi by the ABC transporter P-glycoprotein (P-gp, ABCB1, MDR1), and the other involving retrograde transport of GlcCer by FAPP2 to the ER, followed by entry into the vesicular transport system for Golgi lumenal access. To examine the in vivo involvement of P-gp in GSL metabolism, we generated a knockout model by crossbreeding the Fabry disease mouse with the P-gp knockout mouse. HPLC analyses of tissue Gb3 levels revealed a tissue-specific reduction in MDR1/Fabry mice. TLC analyses, however, did not show such reduction. In addition, we performed a gene knockdown study using siRNA against P-gp and FAPP2. Results show these siRNA to have distinct effects on GSL levels that are cell-type specific. These results give rise to the prospect of unique therapeutic approaches by targeting P-gp or FAPP2 for synthesis inhibition of particular GSL pathways. Sphingolipids Metabolism Lysosomal storage disorders adamantane Glucosylceramide Lactosylceramide P-glycoprotein MDR1 Gaucher disease Fabry disease siRNA Gb2 galabiosylceramide Glycolipids Inhibitors Knockout mouse Crossbreeding Glucosylceramide synthase Lactosylceramide synthase Ganglioside Globo-series Gb3 synthase pharmacological chaperone Glucocerebrosidase Substrate reduction therapy ATP8B1 Cholesterol ABC Transporters P-type ATPase Flippase FAPP2 GLTP Glycosyltransferase Glycolipid analogues ERAD ABCB1 knockdown GM3 and EGFR GM3 and insulin receptor Glycolipid synthesis Glycolipid metabolism enzyme enhancement therapy 0487 0307 0491 0379 0306

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