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ELAIA

Abstract

Tay-Sachs disease (TSD, also known as GM2-gangliosidosis) is an incurable autosomal-recessive neurodegenerative lysosomal storage disease caused by a mutation in the HEX A gene that codes for the lysosomal enzyme β-hexosaminidase A (Hex A). For patients with TSD, GM2-gangliosides cannot be properly broken down, and, as a result, accumulate in their neurons, causing severe neurological complications. Although all past treatment options have been ineffective, this study set out to reduce the number of GM2-gangliosides in cells by increasing Hex A activity using novel pharmacological chaperone therapy.

Four factors, DMSO, glutamic acid, Pyrimethamine, and a decrease in temperature, were assessed for their ability to ameliorate Hex A activity in TSD cells and decrease the GM2-ganglioside buildup in a TSD derived cell line, GM00502. The human kidney fibroblast cell line contains two of the most common mutations that cause TSD (1278ins4 and 1421+1G→C). The effects of the chaperones outlined in this project have yet to be tested on a cell line with both of these major mutations. I hypothesized that temperature reduction, DMSO, glutamic acid, and pyrimethamine would rescue Hex A activity in the TSD derived human kidney fibroblast cell line GM00502.

A study in cytotoxicity was conducted to find the optimum concentration of DMSO, glutamic acid, and Pyrimethamine to treat both GM00502 and HEK293 (control) human kidney fibroblasts. After confirming proposed treatment concentrations were not cytotoxic, a gradient of three concentrations of each factor was then used in the subsequent testing phase. Differences in GM2-ganglioside levels were quantified through the use of LysoTracker DND-26 staining and fluorescence microscopy. GM00502 TSD derived cells were shown to contain an increased accumulation of GM2-gangliosides when compared to the unafflicted HEK293 control cells. After treating GM00502 cells with DMSO, glutamic acid, Pyrimethamine, and a temperature reduction it was found that all treatments were able to reduce the overall GM2-ganglioside level. Likewise, each treatment was also able to further reduce the GM2-ganglioside levels in HEK293 cells. Of the four factors tested, glutamic acid appeared the most effective in decreasing lysosomal accumulation in both cell types (p<0.05). Pyrimethamine also appeared to be effective at decreasing lysosomal accumulation in GM00502 cells (p<0.005).

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