Development of photoactivable ApoE for in vivo tracking 3854

Abstract Description Our objective was to develop a system for tracking cell-type specific ApoE trafficking in vivo to better understand its role in cardiovascular and neurodegenerative diseases. We engineered a phototagged ApoE construct with an N-terminal Kikume Green-Red (KikGR) fluorophore that irreversibly converts from green to red after 405nm excitation, allowing spatiotemporal tracking of ApoE movement. Using in vitro transfection and AAV-mediated transduction in vivo, we validated that KikGR-ApoE is properly secreted as lipidated particles and can be photoconverted. Tracking hepatic KikGR-ApoE revealed novel trafficking patterns: uptake by enteric neurons, accumulation in kidney glomeruli, and no CNS penetration. We observed isoform-specific differences where KikGR-ApoE2 showed higher plasma levels than KikGR-ApoE4, consistent with reduced LDLR binding, while KikGR-ApoE4 formed hepatic aggregates. These findings demonstrate that photoactivatable ApoE enables precise tracking of isoform-specific ApoE trafficking between organs and cell types, revealing new insights into ApoE biology. Current work expanding to astrocyte-specific expression will define ApoE movement through systemic circulation and lymphatics in both homeostatic and disease conditions. Funding Sources NIH P01 AG078106 Topic Categories Technological Innovations in Immunology (TECH)