Boulanger, LisaNguyen, Ai Vy2022-07-152026-09-292022-07-152026-09-292022-04-222022-07-15http://arks.princeton.edu/ark:/88435/dsp01rv042x23vhttps://theses-dissertations.princeton.edu/handle/88435/dsp01rv042x23vRecombinant Adeno-associated Virus (rAAV) is one of the most widely used tools for neurobiological research and gene replacement therapy to treat a variety of diseases. Although AAVs have been known to be nonpathogenic and do not cause any human diseases, research over the past few decades has unmasked a variety of immunotoxicity effects in the periphery and neuroinflammatory responses in the central nervous system (CNS) following the administration of AAV. Upon the detection of CpG motifs in the viral genome, Toll-like receptors 9 (TLR9) are activated and subsequently, trigger immune responses that are capable of clearing the virus from the body and limiting transgene expression. Many immune molecules engaged downstream of TLR9 activation also play a role in regulating and modulating the structure and function of CNS cells, indicating that immune responses to AAV may also disrupt neuronal morphology and functions. Building on the previous work in the Boulanger Lab to explore the mechanisms underlying AAV-associated and TLR9-dependent dendritic simplification, this study demonstrated that AAV administration alters cell density in vivo, is not sufficient to cause dendritic simplification in vitro, and worked to explore a potential approach to limit TLR9 activation by the means of CpG depletion in the viral genome. Understanding the mechanisms underlying AAV-induced toxicity is critical to developing AAV vectors with higher efficacy and higher safety for gene replacement therapy.application/pdfenPrinceton University Senior Theses