Central Nervous System Targeting Nanovesicles for Trans-Barrier Delivery and Spinal Cord Injury Treatment

The central nervous system (CNS) barrier obstructs therapeutic component entrance and hinders the therapy efficiency of CNS diseases. An ideal delivery system should penetrate and concentrate in the CNS without safety concerns. Nanovesicles (NVs) are a popular delivery tool, because of their biological homology, inherent homing effects, and capacity to penetrate barriers. However, the delivery efficacy of NVs is insufficient for CNS disease therapy, and the mechanism for barrier penetration remains elusive. Herein, nanovesicles (NVs) were extruded from mesenchymal stem cells and modified by a lesion tissue affinity peptide (CAQK) for spinal cord injury (SCI) therapy. The NVs penetrated endothelial barriers effectively in vitro. Subsequently, the CNS barrier penetration capacity of the CAQK-conjugated NVs (CNVs) was verified in vivo in spinal cord injury (SCI) and the temporary middle cerebral artery occlusion (t-MCAO) mouse models. Furthermore, the endothelial barrier penetration of CNVs depended on the active endocytosis by endothelial cells. After endocytosis, the Rab11+ endosome was identified to mediate a transcellular transcytosis to transport CNVs across the barrier. In the SCI model, CNVs promoted the lesion tissue accumulation, leading to improvement in the neural functional recovery. In summary, we developed a natural NV tool for SCI therapy, employing the inherent CNS barrier penetration capacity and enhanced lesion tissue homing characteristics of NVs. The NVs crossed the CNS barriers via active endocytosis, followed by Rab11+ endosome-mediated transcytosis. The CNV exhibited good delivery efficacy and therapeutic effects in CNS diseases and has the potential for clinical translation.