The let-7i-5p in ReN cell-derived nanovesicles exerts neuroprotective effects via anti-apoptotic mechanisms in Parkinson’s disease models

To investigate the neuroprotective effects of nanovesicles (NVs) derived from the human neural stem cell line ReN cell and to explore the underlying molecular mechanisms in Parkinson’s disease (PD).

PD mouse models were established in C57BL/6 mice by intraperitoneal injection of 20 mg/kg 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Mice were treated via tail vein injection with nanovesicles obtained from extruded ReN cells (ReN-NV) or RVG peptide-modified ReN-NV (RVG-ReN-NV). Motor function was evaluated by the rotarod test and the pole test, and immunofluorescence staining was performed to assess the expression of tyrosine hydroxylase (TH) and the microglial marker Iba1 in the substantia nigra, as well as TH expression in the striatum. Western blot analysis was used to determine TH protein levels in the striatum. In vitro, a PD cell model was established by treating human neuroblastoma SH-SY5Y cells with 1 mmol/L 1-methyl-4-phenylpyridinium ion (MPP⁺). Cell viability was assessed using the CCK-8 assay, cytotoxicity was evaluated by lactate dehydrogenase (LDH) release assay, and the protein expression levels of Bcl-2 and Bax were measured by Western blotting.

The behavioral results showed that MPTP-treated mice displayed a significantly reduced latency to fall during the pole test, accompanied by an increased total descent time, suggesting the establishment of Parkinsonian-like motor impairment. Immunofluorescence analysis showed that ReN-NV alleviated the loss of TH-positive neurons in the substantia nigra and striatum induced by MPTP and reduced Iba1 expression in the substantia nigra, with RVG-ReN-NV exhibiting a more pronounced protective effect. Western blot analysis demonstrated that ReN-NV upregulated TH protein expression in the striatum. In vitro experiments showed that ReN-NV increased the viability of MPP⁺-treated SH-SY5Y cells, reduced LDH release, upregulated the expression of the anti-apoptotic protein Bcl-2, and downregulated the expression of the pro-apoptotic protein Bax.

ReN cell-derived nanovesicles exert significant neuroprotective effects in MPTP/MPP⁺-induced PD models. RVG modification further enhances their brain-targeting protective efficacy, and the underlying mechanism may be associated with let-7i-5p-mediated inhibition of apoptotic pathways.