Using an engineered human hexosaminidase as an enzyme replacement therapy to treat a mouse model of Tay-Sachs Disease

Simple item page
dc.contributor.authorAshiri, Mehrafarin
dc.contributor.examiningcommitteeHicks, Geoffrey (Biochemistry and Medical Genetics)en_US
dc.contributor.examiningcommitteeMiller, Donald (Pharmacology and Therapeutics)en_US
dc.contributor.supervisorMark, Brian
dc.contributor.supervisorTriggs-Raine, Barbara
dc.date.accessioned2023-04-04T19:05:37Z
dc.date.available2023-04-04T19:05:37Z
dc.date.copyright2023-03-27
dc.date.issued2023-03-23
dc.date.submitted2023-03-27T16:32:28Zen_US
dc.degree.disciplineBiochemistry and Medical Geneticsen_US
dc.degree.levelMaster of Science (M.Sc.)en_US
dc.description.abstractTay-Sachs disease (TSD) is a rare genetic disorder arising from mutations in the gene encoding the α-subunit of β-hexosaminidase A (HexA). Hexosaminidase A is a member of a family of enzymes that are involved in the degradation of glycoconjucates including glycolipids and glycosphingolipids. These molecules are components of cell membranes and have important roles in cellular signaling processes, cell-surface recognition, cell proliferation, and neurotransmission, among other functions. HexA enzyme deficiency leads to progressive buildup of GM2 ganglioside in the central nervous system (CNS) and other tissues throughout the body. Excessive GM2 ganglioside storage in the CNS leads to neuronal death with devastating neurological and psychiatric consequences such as cognitive impairment and intellectual disability, locomotion dysfunction, seizures, and respiratory failure. Although various treatment strategies have been investigated, there are no known effective treatments for TSD other than mitigating the associated symptoms. Lack of an effective treatment results in death at the age 4-5 in the most severe form of TSD known as infantile TSD. One of the therapeutic strategies which is based on the ability of cells to take up exogenous enzyme is enzyme replacement therapy (ERT). Therefore, ERT can increase the enzyme activity in enzyme deficient cells to therapeutic levels, which is known as an effective treatment strategy for other lysosomal storage disorders (LSDs). In the present study we used HexM, a human based engineered enzyme harbouring the critical aspects of HexA enzyme, which made it a suitable candidate to improve the efficacy of ERT. To evaluate the therapeutic efficiency of a M6P-HexM and its hyperphosphorylated form; M6P-PhosHexM, we used intracerebroventricular (ICV) ERT in a TSD comparable mouse model. Assessing the biodistribution of enzymes suggested that M6P-HexM had a longer circulation time in the blood compared to M6P-PhosHexM. We also observed that after administrating the enzymes through the vein, liver enzyme activity was significantly enhanced in comparison to activity in HexA deficient animals. Brain’s enzyme activity suggested an elevation post M6P-HexM IV-infusion compared to controls. Histological analysis of brain tissue post ICV-ERT showed a reduction in the accumulated GM2 ganglioside. Delivering the enzymes directly into the cerebrospinal fluid through ICV-cannulation resulted in an increase in the ratio of GM3/GM2 ganglioside in the hippocampal region and near the implanted cannula.en_US
dc.description.noteMay 2023en_US
dc.identifier.urihttp://hdl.handle.net/1993/37251
dc.language.isoengen_US
dc.rightsopen accessen_US
dc.subjectTay-Sachs diseaseen_US
dc.subjectTSDen_US
dc.subjectmice modelen_US
dc.subjectEnzyme replacement therapyen_US
dc.subjectERTen_US
dc.subjectICV-ERTen_US
dc.subjectIntracerebroventricular injectionen_US
dc.subjectStereotaxic surgeryen_US
dc.subjectHexMen_US
dc.subjectM6P-HexMen_US
dc.subjectM6P-PhosHexMen_US
dc.subjectPhosHexMen_US
dc.subjectCellular uptakeen_US
dc.subjectBiodistributionen_US
dc.subjectMALDIen_US
dc.subjectMALDI-IMSen_US
dc.subjectMALDI analysisen_US
dc.subjectMALDI mass spectroscopyen_US
dc.subjectβ-hexosaminidase Aen_US
dc.subjectlysosomal storage disordersen_US
dc.subjectGM2 gangliosideen_US
dc.subjectGM3 gangliosideen_US
dc.subjectGM2 gangliosidosisen_US
dc.titleUsing an engineered human hexosaminidase as an enzyme replacement therapy to treat a mouse model of Tay-Sachs Diseaseen_US
dc.typemaster thesisen_US
local.subject.manitobanoen_US
oaire.awardNumberPJT-162414en_US
oaire.awardTitleCanadian Institutes of Health Researchen_US
project.funder.nameCanadian Institutes of Health Researchen_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Ashiri_Mehrafarin.pdf
Size:
24.99 MB
Format:
Adobe Portable Document Format
Description:
Thesis
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
2.2 KB
Format:
Item-specific license agreed to upon submission
Description:
Download
Collections
FGS - Electronic Theses and Practica