Multicompartment Quantitative Proteomics Revealing Potential Mechanisms Underlying the Treatment Effects of Mesenchymal-Derived Extracellular Vesicles in a Monkey Model of Cortical Injury

Previous
studies have demonstrated that mesenchymal stromal
cell-derived
extracellular vesicles (MSC-EVs) enhance functional recovery after
cortical injury in rhesus monkeys by reducing chronic microglial inflammation,
neuronal damage, and myelination deficits. However, the signaling
pathways underlying these therapeutic effects remain largely unexplored.
In this study, employing a reliable quantitative proteomics platform
UHR-IonStar, we identified the protein cargo of MSC-EVs infused intravenously
to rhesus monkeys 24 h and 2 weeks post-injury to the motor cortex.
We then analyzed global protein expression changes across cerebrospinal
fluid (CSF), plasma, and brain tissue of MSC-EV-treated versus vehicle-treated
female, aged rhesus monkeys. A total of 1241/431/4124 monkey proteins
were reliably quantified in CSF/plasma/tissue samples, respectively.
Longitudinal analysis of CSF and plasma samples highlighted a shift
from MSC-EV modulation of inflammatory and metabolic proteins in plasma
at early recovery (2 weeks), toward modulation of plasticity-related
proteins in CSF and brain tissue at later stages (4 weeks). Further
protein–protein interaction analysis identified potential MSC-EV
targets related to complementary signaling, proteolysis, and aminoglycan
stability, which aligned with our previous findings. This comprehensive,
multicompartment monkey proteomics study advances understanding of
MSC-EV contents and treatment effects, paving the way for novel treatment
of cortical injury.