Engineered Heterochronic Parabiosis on 3D Microphysiological Systems

PROJECT SUMMARY Heterochronic parabiosis, in which young and aged animals are surgically attached to share circulation, provided evidence of putative ‘anti-geronic’ factors exist but the mechanisms by which circulating factors mediate rejuvenating properties on muscle stem cells and their microenvironment have yet to be elucidated. Due to the complexity of in vivo parabiosis and the dynamic nature of blood-borne factors, reliable identification of these humoral factors remains a major hurdle. To overcome this challenge, Dr. Jang and his team will leverage advanced microengineering approaches to build a 3D microfluidic parabiosis circuit that can control mechanical and biochemical cues in the physiologically relevant 3D microenvironment. In this proposal, his team will further refine and upgrade the in vitro parabiosis platform by integrating a cell-type-specific protein labeling system (MetRSL2774G transgene) to precisely identify muscle secretome, also known as myokines, responsible for rejuvenation effects on muscle stem cells. In addition, the targeted genetics approach will be employed to delineate oxidative stress-induced pro-geronic myokines that negatively impact muscle stem cell function. Finally, the team will also engineer an exercise-induced myokine reporter system within parabiosis-on-a-chip using an optogenetic actuator (Channelrhodopsin 2) co-expressed with protein labeling construct, MetRSL274G. Using this reporter, proposed studies will identify novel contraction-induced myokines with anti-geronic properties and myokines that pass the blood-brain-barrier (BBB) to exert their action on muscle-brain crosstalk. The successful outcomes of this project will have far and broad implications in geroscience. This minimally invasive 3D microphysiological system can be exploited in a variety of studies testing the hallmarks of aging or modeling of age-related diseases in vitro. More importantly, upon validation, the experimental approach used in this proposal can be translated to mimic human parabiosis, which will have significant clinical implications.