Effects of Simultaneous Amyloid-Beta 42 and Heparan Sulfate Proteoglycan Expression on Alzheimer's Disease Incidence in Drosophila melanogaster Flies

Abstract

Alzheimer’s disease is a serious neurological disorder that increases in severity with age. Previous research has correlated Alzheimer’s disease with the formation of amyloid-beta 42 (AB42) protein aggregates. Heparan Sulfate Proteoglycans (HSPGs) are a type of molecule known to interact with protein aggregates. Relatively little research exists studying the relationship between HSPGs and Alzheimer’s disease. Given this, the effects of HSPG overexpression and sulfation on Alzheimer’s disease formation in AB42-overexpressing Drosophila flies was investigated. Climbing assays were performed on Drosophila flies overexpressing AB42 and HSPG dally, and on Drosophila overexpressing AB42 and expressing non-sulfated HSPGs. Control group flies genetically identical to these groups with wild-type expression were also tested. Climbing assays were performed throughout the lives of Drosophila, with group average pass rates being recorded at each tested age. Ultimately, flies overexpressing HSPGs and AB42 experienced increased motor and cognitive degradation with age, whereas flies expressing un-sulfated HSPGs and AB42 experienced less degradation than controls. These results suggest that the interaction of HSPGs with AB42 may be significant to Alzheimer’s disease development in Drosophila and that this interaction may be dependent on the sulfated status of HSPG. However, experimental results were somewhat confounded by the absence of a Drosophila group dedicated to exclusively overexpressing AB42 in the absence of HSPGs.