Deficiency of parkin causes neurodegeneration and accumulation of pathological α-synuclein in monkey models
Rui Han, … , Xiao-Jiang Li, Weili Yang
Rui Han, … , Xiao-Jiang Li, Weili Yang
Published October 15, 2024
Citation Information: J Clin Invest. 2024;134(20):e179633. https://doi.org/10.1172/JCI179633.
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Deficiency of parkin causes neurodegeneration and accumulation of pathological α-synuclein in monkey models

Abstract

Parkinson’s disease (PD) is characterized by age-dependent neurodegeneration and the accumulation of toxic phosphorylated α-synuclein (pS129-α-syn). The mechanisms underlying these crucial pathological changes remain unclear. Mutations in parkin RBR E3 ubiquitin protein ligase (PARK2), the gene encoding parkin that is phosphorylated by PTEN-induced putative kinase 1 (PINK1) to participate in mitophagy, cause early onset PD. However, current parkin-KO mouse and pig models do not exhibit neurodegeneration. In the current study, we utilized CRISPR/Cas9 technology to establish parkin-deficient monkey models at different ages. We found that parkin deficiency leads to substantia nigra neurodegeneration in adult monkey brains and that parkin phosphorylation decreases with aging, primarily due to increased insolubility of parkin. Phosphorylated parkin is important for neuroprotection and the reduction of pS129-α-syn. Consistently, overexpression of WT parkin, but not a mutant form that cannot be phosphorylated by PINK1, reduced the accumulation of pS129-α-syn. These findings identify parkin phosphorylation as a key factor in PD pathogenesis and suggest it as a promising target for therapeutic interventions.

Authors

Rui Han, Qi Wang, Xin Xiong, Xiusheng Chen, Zhuchi Tu, Bang Li, Fei Zhang, Chunyu Chen, Mingtian Pan, Ting Xu, Laiqiang Chen, Zhifu Wang, Yanting Liu, Dajian He, Xiangyu Guo, Feng He, Peng Wu, Peng Yin, Yunbo Liu, Xiaoxin Yan, Shihua Li, Xiao-Jiang Li, Weili Yang

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Figure 5

Age-dependent reduction of pS65-parkin phosphorylation and increase of pS129-α-syn.

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Age-dependent reduction of pS65-parkin phosphorylation and increase of p...
(A) pS65-parkin is more abundant in neuronal cells in the SN. The large-sized neurons (arrows) in the SN could be identified by double immunostaining with mouse anti-NeuN and rabbit anti-pS65-parkin. (B) Representative images of immunostaining showing decreased pS65-parkin and increased pS129-α-syn in the SN of the 25-year-old monkey when compared with the 8-year-old monkey brain. (C) Western blotting revealing age-dependent decline of pS65-parkin in the monkey brains. (D) Western blotting analysis was performed to examine parkin distribution in the soluble and insoluble fractions of the gray matter and white matter of the monkey brain cortex at 8 and 25 years of age. (E) The soluble (S) and insoluble (I) protein fractions were extracted from the SN tissues of young (7 and 8 years) and old (25 and 26 years) monkeys. Western blot analysis revealed increases in parkin and pS129-α-syn in the insoluble fraction of the aged monkey brains. The ratios of parkin and pS129-α-syn to vinculin are presented beneath the blots. In C–E, Western blot images represent the results in 3 independent experiments. (F) Representative images of immunostaining demonstrated an increase in γH2AX, 8-OhdG, and ubiquitination in the SN of the 25-year-old monkey compared with the 8-year-old monkey. (G) Quantification of the relative levels of immunostaining signals in E using 4–8 brain sections of each group (n = 2 animals per group). Representative Western blotting results and immunostaining images are from at least 3 independent experiments of 2 biological replicates.