Establishment of an endogenous cardiac exosome tracking system Grant uri icon


  • Exosomes, small secreted extracellular vesicles, are emerging as a new category of messengers for in vivo communication amongst cells and organs. The beneficial effects of exosomes on the injured heart have been demonstrated with promising results. Understanding the biodistribution and kinetics of endogenous exosomes in the heart will have a significant impact on exosome-mediated basic and translational studies. However, there is a technological gap and demand in the field for a sensitive and noninvasive tracking system for endogenous exosomes. To meet the demand, we propose to generate a transgenic mouse expressing bioluminescent reporter NanoLuc-fusion protein. The ultrasensitive Nano-luciferase (NanoLuc) reporter will be fused with the exosome surface marker CD63 in order to specifically label exosomes. Then, the cardiomyocyte-specific alpha-MHC promoter followed by a loxP-STOP-loxP cassette will be engineered in order to specifically label exosomes of cardiomycyte origin. Finally, the mouse will be bred with a tamoxifen-inducible Cre mouse, allowing for temporally regulated tissue-specific labeling of exosomes. This will be the first mouse model that enables the tracking of endogenous exosomes derived from cardiomyocytes by bioluminescence in vivo. Innovation and application: 1) Endogenous exosomes from cardiomyocytes can be labeled and detected by bioluminescence in vivo, providing great novelty for the progression of exosome studies. 2) The use of CD63NanoLuc as the exosome tag provides the most sensitive (150-fold stronger signal compared to the traditional luciferases) and stable signal (the longest amongst all of the known luciferases) to enable non-invasive exosome detection. 3) The mouse model enables spatial and temporal control of endogenous exosome labeling, which has a broad spectrum of applications. Impact: The mice will be the first model to allow tracking endogenous exosomes released from cardiomyocytes. Such a system will provide a powerful tool for the exploration of the biological functions and clinical applications of exosomes, such as cell-to-cell signaling between cardiomyocytes and non-cardiomyocytes as well as communication from the heart to other organs through exosomes. The approach is superior to current ex vivo and in vivo labeling. (AHA Program: Innovative Project Award)

date/time interval

  • 2018 - 2020