Wnt1 Promotes EAAT2 Expression and Mediates the Protective Effects of Astrocytes on Dopaminergic Cells in Parkinson’s Disease

الملخص EN

Background.

Wnt/β-catenin signaling has been reported to exert cytoprotective effects in a cellular model of Parkinson’s disease (PD).

Glutamate excitotoxicity has been suggested to contribute to the pathogenesis of PD, and excitatory amino acid transporters (EAATs) play a predominant role in clearing excessive glutamate.

EAAT2 is mainly expressed in astrocytes, which are an important source of Wnt signaling in the brain.

Methods.

Wnt1-overexpressing U251 astrocytes were indirectly cocultured with dopaminergic SH-SY5Y cells treated with 6-hydroxydopamine (6-OHDA).

Cell toxicity was determined by cell viability and flow cytometric detection.

Glutamate level in the culture medium was determined by enzyme-linked immunosorbent assay (ELISA).

Western blot analysis was used to detect the expression of Wnt1, β-catenin, and EAAT2.

Immunofluorescence was used to display the expression and translocation of NF-κB p65.

Results.

6-OHDA treatment significantly decreased cell viability in both U251 cells and SH-SY5Y cells, inhibited the expression of Wnt1, β-catenin, and EAAT2 in U251 cells, and increased the glutamate level in the culture medium.

Coculture with Wnt1-overexpressing U251 cells attenuated 6-OHDA-induced apoptosis in SH-SY5Y cells.

Overexpression of Wnt1 decreased the glutamate level in the culture media, upregulated β-catenin, EAAT2, and NF-κB levels, and promoted the translocation of NF-κB from the cytoplasm to the nucleus in U251 cells.

Conclusion.

Wnt1 promoted EAAT2 expression and mediated the cytoprotective effects of astrocytes on dopaminergic cells.

NF-κB might be involved in the regulation of EAAT2 by Wnt1.