Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / It is the purpose of this thesis to present the results of exploratory studies on the subcellular localization of human brain ganglioside. Subcellular localization have been limited to rat and guinea pig brain. In addition, data derived from five different methods for the preparation of subcellular particles are compared. Ganglioside is a generic name for a group of complex acidic glycolipids containing fatty acid, sphingosine, hexose, hexosamine, and sialic acid (n-acetyl neuraminic acid, NANA) moieties. This substance was first isolated in 1935 from the brains of children afflicted with Niemann-Pick and Tay-Sachs diseases. This glycolipid was found to differ from the chemically related cerebrosides in its solubility properties and in its red-violet color reaction in the Bial's orcinol test. The moiety of ganglioside responsible for the positive Bial's orcinol test was isolated by hydrolysis and given the name neuraminic acid. Subsequent investigators have used the concentration of n-acetyl neuraminic acid as a measure of ganglioside purity [TRUNCATED] / 2031-01-01

Thesis advisor: Thomas N. Seyfried / Metastasis is the process by which cancer cells disseminate from the primary neoplasm and invade surrounding tissue and distant organs, and is the primary cause of morbidity and mortality for cancer patients. Most conventional cancer therapies are ineffective in managing tumor metastasis. This has been due in large part to the absence of in vivo metastatic models that represent the full spectrum of metastatic disease. Here I identify three new spontaneously arising tumors in the inbred VM mouse strain, which has a relatively high incidence of CNS tumors. Two of the tumors (VM-M2 and VM-M3) reliably expressed all of the major biological processes of metastasis to include local invasion, intravasation, immune system survival, extravasation, and secondary tumor formation involving liver, kidney, spleen, lung, and brain. Metastasis was assessed through visual organ inspection, histology, immunohistochemistry, and bioluminescence imaging. The metastatic VM tumor cells also expressed multiple properties of macrophages including morphological appearance, surface adhesion, phagocytosis, gene expression (CD11b, Iba1, F4/80, CD68, CD45, and CXCR4) and total lipid composition (glycosphingolipids and phospholipids). The third tumor (VM-NM1) grew rapidly and expressed properties of neural stem/progenitor cells, but was neither invasive nor metastatic. This thesis research also examined the influence of a genelinked up-regulation of the simple ganglioside GM3 in the metastatic VM-M3 tumor. Ganglioside GM3 has been shown to have anti-invasive effects through its ability to modulate integrins and matrix metalloproteases. Additionally, GM3 was previously shown to be elevated in resting macrophages when compared to activated macrophages. The bioluminescent VM-M3 cells (M3/Fluc) contain mostly GM2, GM1, and GD1a with undetectable levels of GM3. Additionally, the M3/Fluc cells express GalNAc-T, a key enzyme for the synthesis of complex gangliosides from GM3, the precursor used for complex ganglioside biosynthesis. Stable transduction of the M3/Fluc tumor with a lentiviral vector containing a cDNA sequence targeting the GalNAc-T gene (Fluc-TNG), resulted in a knock-down of GalNAc-T expression and an up-regulation of GM3 compared to the control (Fluc-csh) transduced M3/Fluc tumor cells. In vivo, the Fluc-TNG cells were significantly less invasive when implanted in the brain and less metastatic when implanted in the flank when compared to the control Fluc-csh tumors. My data indicate that spontaneous brain tumors can arise from different cell types in VM mice and that the ganglioside GM3 can inhibit invasion and metastasis in metastatic cancer cells with macrophage properties. The new VM tumor model will be useful for defining the biological processes of cancer metastasis and for evaluating potential therapies for tumor management. / Thesis (PhD) — Boston College, 2008. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

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Prostate cancer (CaP) is the 2nd most common cancer in North American men. Tumour management strategies are appropriate for early stage disease, but advanced disease has a poor prognosis and requires prompt treatment. Therefore, research into delay of tumour progression and efficacious treatment of aggressive cancer are of interest. Ganglioside was assessed for its role in altering markers of metastatic potential and susceptibility of CaP to adenovirus-mediated gene therapy. Healthy (RWPE-1) and malignant (DU-145, PC-3) prostate cells were cultured with or without mixed ganglioside. Differences in growth, ganglioside and integrin densities, and adenoviral infectivity were assessed between treatment and control groups. Ganglioside decreased (p<0.01) growth of PC-3 cells relative to untreated control. Ganglioside decreased (p<0.01) GD1a and increased (p<0.04) integrin densities in malignant prostate cells, suggesting ganglioside may increase metastatic potential of CaP. Ganglioside significantly increased adenovirus entry in PC-3 cells, thereby improving susceptibility of CaP to adenovirus-mediated gene therapy. / Nutrition and Metabolism

The skyrocketing costs of prescription medicine in developed countries and their lack of availability in developing countries are the most challenging problems of human health. Primary reasons for such high cost are fermentation-based production, expensive purification methods, the need for low temperature storage and transportation and the delivery through sterile injections. Most of these expenses could be minimized or eliminated when therapeutic proteins are expressed and orally delivered via plant cells. Chloroplasts have the machinery to fold complex and biologically active eukaryotic proteins in the soluble chloroplast stromal compartment. Protein expression through chloroplast transformation system offers a number of advantages over nuclear transformation such as a high level of transgene expression (up to 47% of the total soluble protein), due to the presence of 10,000 copies of the transgene per cell, which is uniquely advantageous for oral delivery of adequate amounts of the therapeutic protein or vaccine antigen. It is also an environmentally friendly approach due to effective gene containment and lack of transgene expression in pollen since the chloroplast genome is maternally inherited. To study receptor-mediated oral delivery of therapeutic proteins using the transmucosal carrier cholera toxin B subunit (CTB), a CTB-GFP fusion protein separated by a furin cleavage site was expressed via the tobacco chloroplast genome and used as a visible marker. Site specific integration of the transgene was confirmed by PCR analysis. Southern blot analysis confirmed homoplasmy. Immunoblot analysis confirmed the expression of both the monomeric as well as the pentameric forms of CTB-GFP in transgenic plants. Expression levels of upto 21.3% were obtained and the functionality of the CTB-GFP pentamers was confirmed by an in vitro GM1 binding assay. GFP was seen in the intestinal mucosa, liver and spleen of mice orally fed with CTB-GFP expressing leaves, while CTB was detected only in the intestinal cells. Intestinal macrophages and dendritic cells stained positive for both the CTB as well as GFP. These results suggest successful cleavage of the foreign protein from the transmucosal carrier and its delivery to various organs. These investigations should facilitate the development of a novel cost-effective oral delivery system for plant-derived therapeutic proteins.

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.

Intestinal enteropathy is a prevalent yet neglected aspect of child malnutrition involving chronic exposure to intestinal pathogens such as Giardia intestinalis. Gangliosides have therapeutic potential for the treatment of giardiasis and intestinal enteropathy. The objectives of the thesis were to 1. assess the Giardia carriage patterns in daycares in Guatemala, 2. compare anthropometric data between Giardia carriers and non-carriers, 3. compare sensitivity and specificity of 3 Giardia diagnostic methods (ProSpecT-Giardia-EZ-Microplate assay, RidaQuick Giardia dipsticks and microscopic analysis using the sucrose concentration gradient method). Giardia prevalence rates were high (close to 44%), most cases of infection were chronic (5-week study period), and malnutrition (lower weight-for-age Z-scores) may be associated to higher intensity of infection. ELISA was the most sensitive Giardia diagnostic test. Compared to ELISA, the microscopic and dipstick analysis had sensitivities of 53.6% and 60.7%, and specificities of 100% and 97.9%, respectively, within a set of 75 stool samples. / Nutrition & Metabolism

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The sciatic nerves of rats were crushed with fine forceps and allowed to survive for 3 or 7 days, at which time the 5th lumbar dorsal root ganglion was injected with [3H]glucosamine. Animals were killed 18 h later and the nerves proximal and distal to the crush site were cut into 3 mm segments. Gangliosides were purified from these segments, and radioactivity was separately measured in gangliosides, neutral glycolipids and glycoprotein. For all 3 fractions, radioactivity was distributed similarly between the crush site the point of maximum axonal elongation. A second smaller peak of ganglioside radioactivity was seen to span a few segments immeidately distal to the point of maximum axonal elongation. We propose two possible explanation for this: (1) it represents ganglioside synthesis by Schwann cells (from blood-borne [3H]glucosamine) as part of the mitogenic response of these cells to the reappearance of axons; or (2) recently synthesized, transported gangliosides are released from the growth cone and taken up by adjacent mitogenic Schwann cells.