Neurodevelopmental defects and neurodegenerative phenotypes in human brain organoids carrying Parkinson’s disease-linked DNAJC6 mutations

Abstract

Loss-of-function mutations of DNAJC6, encoding HSP40 auxilin, have recently been identified in patients with early-onset Parkinson’s disease (PD). To study the roles of DNAJC6 in PD pathogenesis, we used human embryonic stem cells with CRISPR-Cas9–mediated gene editing. Here, we show that DNAJC6 mutations cause key PD pathologic features, i.e., midbrain-type dopamine (mDA) neuron degeneration, pathologic α-synuclein aggregation, increase of intrinsic neuronal firing frequency, and mitochondrial and lysosomal dysfunctions in human midbrain-like organoids (hMLOs). In addition, neurodevelopmental defects were also manifested in hMLOs carrying the mutations. Transcriptomic analyses followed by experimental validation revealed that defects in DNAJC6-mediated endocytosis impair the WNT-LMX1A signal during the mDA neuron development. Furthermore, reduced LMX1A expression during development caused the generation of vulnerable mDA neurons with the pathologic manifestations. These results suggest that the human model of DNAJC6-PD recapitulates disease phenotypes and reveals mechanisms underlying disease pathology, providing a platform for assessing therapeutic interventions.

The Age of Brain Organoids: Tailoring Cell Identity and Functionality for Normal Brain Development and Disease Modeling

“…DNAJ6 mutant midbrain organoids showed defective wnt signaling at day 15, showing that this mutation has an impact on early neurodevelopment. Less dopaminergic neurons were found, and dopaminergic neuron degeneration was observed in midbrain organoids with DNAJ6 mutation (Wulansari et al, 2021), similarly to previous PD models (Smits et al, 2019). Increased reactive oxygen species (ROS), lower levels of dopamine release, increased α-syn oligomers, mitochondrial and autolysosomal dysfunctions were also observed in mutant midbrain organoids (∼2 months) (Figure 2) (Wulansari et al, 2021).…”

“…Less dopaminergic neurons were found, and dopaminergic neuron degeneration was observed in midbrain organoids with DNAJ6 mutation (Wulansari et al, 2021), similarly to previous PD models (Smits et al, 2019). Increased reactive oxygen species (ROS), lower levels of dopamine release, increased α-syn oligomers, mitochondrial and autolysosomal dysfunctions were also observed in mutant midbrain organoids (∼2 months) (Figure 2) (Wulansari et al, 2021). Mutant midbrain organoids showed an increase in firing frequencies at 2.6 months (DIV80) (Wulansari et al, 2021).…”

“…A recent publication described a model of early-onset PD in which a mutation in DNAJ6, described in familial juvenile parkinsonism, was introduced in hESC using CRISPR-Cas9 (Wulansari et al, 2021). DNAJ6 mutant midbrain organoids showed defective wnt signaling at day 15, showing that this mutation has an impact on early neurodevelopment.…”

“…Increased reactive oxygen species (ROS), lower levels of dopamine release, increased α-syn oligomers, mitochondrial and autolysosomal dysfunctions were also observed in mutant midbrain organoids (∼2 months) (Figure 2) (Wulansari et al, 2021). Mutant midbrain organoids showed an increase in firing frequencies at 2.6 months (DIV80) (Wulansari et al, 2021). The authors correlate this finding with an increase of intrinsic pacemaker frequency, a neuronal characteristic in progressive PD, which is caused by oxidative impairment of A-type Kv4.3 potassium channels (Subramaniam et al, 2014).…”

Gene Therapy for Neurodegenerative Disease: Clinical Potential and Directions

“…A novel mutation in DNAJC6 potentially contributes to early impairment of PD in human embryonic stem cells (hESC) ( Wulansari et al, 2021 ). Moreover, PD-related behavioral deficits have been reported in LIN28A knockout mice ( Chang et al, 2019 ).…”