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 7

DNAJC6 overexpression by CRISPR-SAM (a CRISPRa system) rescues motor deficits and pathological changes in the α-syn-PD mouse model.

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DNAJC6 overexpression by CRISPR-SAM (a CRISPRa system) rescues motor def...
(A) Schematic of the CRISPRa system, illustrating sgRNA-guided DNAJC6 upregulation via demethylase (TET1) and dCas9 fused with the transcriptional activator VP64, delivered using astrocyte- and neuron-targeting AAV vectors. (B) Experimental timeline depicting the in vivo study design. α-Syn-PD models were generated by infecting the midbrain SN with AAV2- or AAV9-α-syn and α-syn PFF, followed by an injection of AAV9 carrying CRISPRa-DNAJC6 1 month later. (C) WB-based determination of DNAJC6 protein expression (left) or mRNA expression of DNAJC6 (right) in the mouse SNs (n = 3–4 independent experiments). (D) Behavioral assessments were conducted 2 months after AAV-CRISPRa-DNAJC6 administration. Rotarod, beam, and pole tests were performed (n = 3–4 independent experiments/animal). (E) Representative immunofluorescence images of dopaminergic neurons in the SN, stained for TH (green) and phosphorylated α-syn (pS129 α-syn, red), comparing WT, PD model, and CRISPRa-AAV-DNAJC6–treated PD model mice. The graph shows the percentage of pS129 α-syn+ neurons and TH+ neurons in the SN in WT, PD model, and PD model with CRISPRa (n = 3–6 independent experiments/animal). (F–H) Quantification of TH+ neuron number (F), soma size (G), and neurite length (H). (I) TH+ immunoreactivity in the striatum. Quantification of TH intensity is shown in the graph. (J and K) Morphometric analysis of astrocytes (J) and microglia (K). More detailed analysis is shown in Supplemental Figure 18. (L) Representative image of microglia immunostained with IBA1 (green), CD11b (red), and CD68 (red) in SN in WT, PD model, and PD model with CRISPRa. Quantification of AIF1+ microglia colocalized with activation markers, ITGAM or CD68 in SN in WT, PD model, and PD model with CRISPRa. N = 3–9 animals/group. *P < 0.05, **P < 0.01, ***P < 0.001; 1-way ANOVA, with Bonferroni’s post hoc analysis. Scale bars: 100 μm (E, I, and L), 25 μm (J).