Dysregulation of astrocytic DNAJC6 contributes to sporadic Parkinson’s disease pathogenesis
Wahyu Handoko Wibowo Darsono, Yeongran Hwang, Erica Valencia, Leonardo Tejo Gunawan, Seung Jae Hyeon, Hoon Ryu, Thor D. Stein, Mi-Yoon Chang, Noviana Wulansari, Sang-Hun Lee
Wahyu Handoko Wibowo Darsono, Yeongran Hwang, Erica Valencia, Leonardo Tejo Gunawan, Seung Jae Hyeon, Hoon Ryu, Thor D. Stein, Mi-Yoon Chang, Noviana Wulansari, Sang-Hun Lee
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Research Article Clinical Research Neuroscience

Dysregulation of astrocytic DNAJC6 contributes to sporadic Parkinson’s disease pathogenesis

Abstract

Loss-of-function mutations in DNAJC6, encoding the cochaperone auxilin (HSP40 family), cause familial juvenile-onset Parkinson’s disease (PD). Given the chaperone role of DNAJC6 in cellular homeostasis in adult neurons, we hypothesized that DNAJC6 dysfunction may not be limited to juvenile-onset disorders but could also be associated with adult-onset brain diseases. Here, we show that DNAJC6 expression is significantly downregulated in postmortem substantia nigra tissues and transcriptomic datasets from patients with late-onset sporadic PD. Consistently, human pluripotent stem cell–derived midbrain cultures exhibited reduced DNAJC6 expression under multiple PD-associated conditions. Mechanistically, DNAJC6 loss resulted from impaired transcription mediated by the midbrain-specific factors NURR1/FOXA2 and reduced protein stability regulated by LRRK2. Beyond neurons, DNAJC6 was robustly expressed in astrocytes and similarly downregulated in sporadic PD contexts. Astrocytic DNAJC6 deficiency impaired phagocytic, autolysosomal, and mitochondrial functions while promoting a proinflammatory phenotype, thereby exacerbating neurodegenerative pathology. Importantly, epigenetic restoration of DNAJC6 in neurons and astrocytes using a CRISPRa-AAV9 system in the substantia nigra of an α-synuclein–induced PD mouse model alleviated behavioral deficits and neuropathology. These findings provide evidence that DNAJC6 dysregulation is associated with pathogenic processes in sporadic PD and suggest that targeting neuronal and astrocytic DNAJC6 could represent a potential disease-modifying strategy.

Authors

Wahyu Handoko Wibowo Darsono, Yeongran Hwang, Erica Valencia, Leonardo Tejo Gunawan, Seung Jae Hyeon, Hoon Ryu, Thor D. Stein, Mi-Yoon Chang, Noviana Wulansari, Sang-Hun Lee

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Figure 3

Decline of DNAJC6 levels in astrocytes within the context of PD.

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Decline of DNAJC6 levels in astrocytes within the context of PD. (A) WB ...
(A) WB analysis showing substantial DNAJC6 protein expression in neurons and astrocytes but not in microglia, all derived from hESCs. n = 3 independent replicates; **P < 0.01, ***P < 0.001; 1-way ANOVA. (B) Decreased DNAJC6 levels in neurons and astrocytes within mixed neuron–astrocyte human midbrain cultures treated with α-syn PFF. Arrowheads indicate representative neurons (TUBB3+) and astrocytes (GFAP+) costained with DNAJC6. The DNAJC6 expression levels in these cell types were estimated by measuring the MFI using LAS image analysis (Leica). A total of 14 neurons or 15 astrocytes were counted (4–5 cells/culture; N = 3 independent cultures); *P < 0.05, ***P < 0.001; nested 2-tailed t test. Scale bars: 50 μm (left), 100 μm (right). (C and D) Downregulation of DNAJC6 (C), and Nurr1 and Foxa2 (D) in human midbrain astrocyte cultures (derived from hESCs) following α-syn PFF treatment, as assessed by WB. n = 3 independent experiments; *P < 0.05; unpaired 2-tailed t test. (E) α-Syn PFF treatment effect on astrocytic LRRK2 activity. LRRK2 kinase activity was estimated by LRRK2 autophosphorylation at Ser935. n = 3 independent experiments; *P < 0.05; paired 2-tailed t test. (F and G) Reduced DNAJC6 expression in midbrain-type neurons and astrocytes carrying LRRK2 mutations. n = 18 cells were counted (6 cells/culture; N = 3 independent cultures); **P < 0.01, ***P < 0.001; nested 1-way ANOVA. Scale bars: 50 μm. (H and I) Reduced DNAJC6 immunoreactivity in DA neurons (melanin+ neurons) (H) and astrocytes (I) of the SN in sporadic PD patients (N = 3) compared with control (N = 3). A total of 30 cells were counted (10 cells/case); **P < 0.01; nested 2-tailed t test. Scale bars: 20 μm.