Human Astrocyte-Based Nanovesicles to Target Neuroinflammation in Alzheimer's Disease

PROJECT SUMMARY-ABSTRACT Astrocytes are specialized glial cells that are highly abundant in the nervous system and that maintain functional homeostasis of neural networks. In the aged and the Alzheimer’s disease brain, astrocytes can contribute inflammatory signaling molecules to the surrounding micro-environment, in turn, negatively impacting

neural function. How can therapeutics, such as anti-inflammatories, be selectively delivered to these dysfunctional astrocytes in order to reduce off-target drug effects on other cells? At present, no effective clinical approaches exist for this purpose. Here, we aim to overcome this lack of technology by formulating lipid

nanovesicles capable of enhanced targeted delivery. Development of this innovative technology will be enabled through the combined expertise of two synergistic laboratories who will bioengineer membrane proteins from human pluripotent stem cell-derived astrocytes into the surface of lipid-based nanovesicles. Our preliminary

studies have revealed that nanovesicles integrated with membrane proteins derived from unique cell sources retain unique cell adhesion proteins that may lead to cell-specific targeting. This finding provoked our hypothesis that nanovesicles coated with adhesion molecules derived from Alzheimer’s disease-model astrocytes (a.k.a.,

AstroVesicles (AVs)) will bind to protein-interacting partners, specifically at the surface of inflammatory astrocytes and, thus, increase cellular uptake by dysfunctional astrocytes. In this way, AVs could be a potential new theranostic tool that allows for the early identification of inflamed areas as well as the delivery of therapeutic

cargo. Astrocyte inflammation will be induced by amyloid beta oligomer treatment to model the Alzheimer’s disease microenvironment and then reactivity will be confirmed by functional calcium imaging and gene expression profiling. To test the hypothesis, in Aim 1, we will formulate nanovesicles and compare the size,

charge, and stability of those containing membrane proteins from naïve and oligomer-treated inflammatory astrocytes as well as from other sources (e.g., neurons, microglia, and cell-derived exosomes). We will perform proteomics-based discovery of the nanovesicles to identify cell-specific proteins with high potential for cell

targeting based on known cell-cell protein interactions. In Aim 2, we will validate the expected capability of AVs to preferentially target astrocytes that are inflamed via amyloid beta oligomer treatment, in comparison to naïve astrocytes and microglia. We will also test potential mechanisms of targeting by interfering with candidate

proteins identified in preliminary data. Our approach will be to measure the presence of AVs upon treatment of sphere cultures composed of astrocytes, neurons, and microglia, using three-dimensional optical imaging and flow cytometry. Notably, these studies will pioneer the use of human neural spheres for nanovesicle testing.

Finally, in Aim 3, we will test whether AVs yield enhanced functional delivery of anti-inflammatories, focusing on the NFB pathway. After optimizing and validating the AVs, we expect this innovative system will be utilized throughout the neuroscience community for cell-targeted therapeutics and imaging tools in Alzheimer’s disease.