UC San Diego

Alzheimer’s Disease (AD) is a devastatingly fatal neurodegenerative disease and a leading cause of dementia around the world. Despite the great medical need, none of the current FDA-approved AD drugs are disease-modifying. Based on a wealth of cell biological and pathological data, amyloid precursor protein (APP) overexpression is believed to contribute to the degeneration of basal forebrain cholinergic neurons (BFCNs) in initiating AD pathogenesis. Therefore, we proposed that reducing APP expression in BFCNs would be a promising AD therapeutic strategy. Antisense oligonucleotides (ASOs) enable selective and potent degradation of target mRNA and are emerging as a powerful new tool for treating Central Nervous System (CNS) disorders. However, a targeting domain is needed to selectively deliver APP ASOs to BFCNs to prevent CNS-wide APP knockdown. To achieve this goal, I developed antibody-RNA conjugates (ARCs) that combine the superb specificity of anti-TrkA antibodies and the potency of APP ASOs to target APP knockdown in BFCNs. To generate ARCs, I explored traditional lysine-based chemical conjugation and site-specific microbial transglutaminase (MTG) biochemical conjugation approaches, each required different antibody routes and conjugation chemistries. Lysine-based conjugation relied on random chemical conjugation through accessible lysines on the antibody surface. Although this approach was effective, it resulted in conjugate heterogeneity and a distribution of Drug:Antibody Ratios (DAR). To produce homogeneous DAR-2 ARCs, I explored site-specific MTG conjugation that targeted conjugation to the engineered tag at the antibody C-terminus. Together, my thesis outlined the framework for the development of ARCs that can be applicable to other neurological disorders.