Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Investigation of the Biological Role of Mouse Acylneuraminyl Hydrolase Enzymes in the Regulation of Neuroinflammation(Izmir Institute of Technology, 2022) Tabakacılar, Doğa; Seyrantepe, VolkanSialidosis is a lysosomal storage disorder, and it is inherited by autosomal recessive mutations in the Neuraminidase 1 (NEU1) gene. Neuraminidases or sialidases are catalytic enzymes that carry out the desialylation of glycoconjugates. Deficiencies of neuraminidases lead to the accumulation of sialoglycoconjugates in membranes of cells. Neuroinflammation and neurodegeneration are present in some lysosomal storage diseases such as Tay-Sachs. However, in the sialidosis mouse model, neuroinflammation was never studied. In this study, we investigated the effect of neuraminidase 1, neuraminidase 3, and their combined deficiency on neuroinflammation by using Neu1-/-, Neu3-/- knockout, and Neu1-/- Neu3-/- double knockout mouse models. Neu1-/- Neu3-/- knockout mouse model was smaller in comparison to its littermates and showed muscle weakness, tremoring, and 2-3 weeks of a lifetime. Some of the Neu1-/- Neu3-/- mice died prematurely. To unravel the pathology immunohistochemical, biological, and chromatographic techniques were used. The expression of inflammatory cytokines was altered in the Neu1-/-, Neu3-/-, and Neu1-/- Neu3-/- mice with respect to the brain section. Neu1-/- Neu3-/- mice showed generally the highest expression of cytokines in the cerebellum compared to the cortex. Neuronal loss was observed in the Neu1-/- Neu3-/- mice in the cortex, thalamus, and cerebellum. The most remarkable change was in the ganglioside expression pattern in the Neu1-/- Neu3-/- mice cortex. GD3 expression was present in the cortex of Neu1-/- Neu3-/- mice where expression of this ganglioside is related to neuroinflammation, neurodegenerative stimuli, autophagosome remodeling and programmed cell death.Master Thesis Investigation of Combined Biological Roles of Neuraminidase 1 and Gm3 Synthase Enzymes in Glycolipid Metabolism(Izmir Institute of Technology, 2020) Can, Melike; Seyrantepe, VolkanGangliosides are sialic acid-containing glycosphingolipids, and commonly expressed in nervous system. GM3 Synthase is responsible for production of GM3 ganglioside known as precursor of a- and b- series gangliosides. Sialidases catalyze removing of sialic acid residues from sialoglycoconjugates and classified based on subcellular localization. Lysosomal Neu1 sialidase is responsible for catabolism of glycolipids, glycoproteins and oligosaccharides. Mutations of lysosomal Neu1 sialidase cause sialidosis and Neu1-/- mice mimic symptoms seen in patients. Glycosphingolipid accumulation in visceral organs of sialidosis patients was notified previously, and it was also reported the GM3 ganglioside as substrate of lysosomal sialidase in vitro. However, effect of Neu1 sialidase in the case of complex ganglioside deficiency in brain remains unclear. In the concept of research, we aimed to understand biological role of lysosomal Neu1 sialidase alone and combined with GM3S in ganglioside metabolism in vivo. In accordance with this purpose, cortex, cerebellum and thalamus tissues of 2- and 5-month old Neu1-/-GM3S-/-, Neu1-/- and GM3S-/- mice were compared with age-matched control group using molecular biological, histological, immunohistochemistry and behavioral analyses. Alterations in ganglioside metabolism, oligosaccharide pattern and cellular processes (ER-oxidative stress, apoptosis), structural abnormalities, glycoconjugate accumulation, loss of neurons and oligodendrocytes in addition to age dependent behavioral impairments in motor function, memory and muscle strength were demonstrated in single and double knock-out mice. In regard of these results, we have concluded that altered glycosphingolipid metabolism with accumulated secondary metabolites like oligosaccharides affect cellular processes and brain pathology resulting in behavioral abnormalities in age dependent and region specific manner.Master Thesis Investigation of Combined Biological Roles of Neuraminidase 1 and N-Acetylgalactosaminyltransferase Enzymes in Glycolipid Metabolism(Izmir Institute of Technology, 2020) Şengül, Tuğçe; Seyrantepe, VolkanGangliosides, sialic acid-containing glycosphingolipids, are responsible for neurogenesis and synaptogenesis which are essential for vertebrate nervous system. N-Acetylgalactosaminyltransferase (Galgt) is glycosyltransferase that plays essential role during complex gangliosides biosynthesis. Expression of Galgt increases at the late stage of development which can be evidence for complex gangliosides role in nervous system development and differentiation.Sialidases are responsible enzymes for sialic acid removal from glycoproteins, glycolipids or oligosaccharides. Neu1 is one of the mammalian sialidase which catabolizes sialoglycoconjugates in lysosomes. Neu1 gene mutations in human result in lysosomal storage disease called sialidosis. Created Neu1 knockout mice model have demonstrated similar symptoms with sialidosis type II. In sialidosis patients, increased ganglioside levels are detected in visceral organs but not in brain. In vitro studies have demonstrated that GM3 is a substrate of Neu1. Until this research, role of Neu1 enzyme on glycosphingolipid metabolism in the absence of complex gangliosides has not been investigated. Therefore this study have been provided comparision of 2-and 4-month-old Neu1-/-, Galgt-/- and Neu1-/-Galgt-/- mice to WT mice and each other by molecular biological, biochemical, histological, immunohistochemical and behavioral analysis in cortex, cerebellum and thalamus regions. In the concept of this thesis, we found effect of single and double deficienct of Neu1 and Galgt enzymes on the distinct cellular events (apoptosis, ER stress, oxidative stress), altered glycolipid and oligosaccharide metabolism, nerve cell death,oligodendrocyte intensity decrease, impairment in locomotor activity, motor coordination, memory capability as age dependent and region specific manner.