Comprehensive Characterization of Nanosized Extracellular Vesicles from Central and Peripheral Organs: Implications for Preclinical and Clinical Applications

Extracellular vesicles (EVs) are nanosized vesicles that have been garnering a lot of attention for their valuable role as potential diagnostic markers and therapeutic vehicles for a plethora of pathologies. While EV markers from biofluids such as plasma, serum, urine, cerebrospinal fluid, and in vitro cell culture-based platforms have been extensively studied, a significant knowledge gap that remains is the characterization of specific organ-derived EVs (ODE). Here, we present a standardized protocol for isolation and characterization of purified EVs isolated from brain, heart, lung, kidney, and liver from rat and postmortem human tissue. Next, using quantitative mass spectrometry-based proteomics, we characterized the respective tissue EV proteomes that identified synaptophysin, caveolin-3, solute carrier family 22 member 2, surfactant protein B, and fatty acid-binding protein 1 as potential markers for the brain, heart, kidney, lung, and liver EV, respectively. These respective tissue-specific markers were further validated using both immunoblotting and a nanoplasmonic platform single EV imaging analysis in the two species. To summarize, our study for the first time using traditional biochemical and high-precision technology platforms provides a valuable proof-of-concept approach in defining specific ODE markers, which could further be developed as potential therapeutic candidates for respective end organ-associated pathologies.