The challenge
PD progressively destroys dopamine neurons in the brain, causing tremors, stiffness, and movement problems. Accumulation of α-synuclein to Lewy bodies and dopaminergic neuron degeneration are central hallmarks with the oxidation of dopamine – turning the neurotransmitter into toxic reactive species – emerging as a key pathological driver. However, the underlying causes of this pathological mechanism in human neurons were unclear.
Our approach
Using PD patient-derived and CRISPR-engineered iPSC midbrain dopaminergic neurons lacking the PD-associated gene DJ-1 (PARK7), we applied in-depth proteomics, state-of-the-art imaging, and ultrasensitive dopamine probes to dissect vesicular dopamine handling and homeostasis. Importantly, loss of DJ-1 function – associated with mitochondrial dysfunction and lack of ATP – is implicated in the more common sporadic form of PD beyond rare mutations.
Our findings
Dysfunction of vesicular monoamine transporter 2 (VMAT2) – the key transporter responsible for packaging dopamine into synaptic vesicles – impairs the ATP-dependent uptake of dopamine into synaptic vesicles, causing oxidation of dopamine, reduced vesicle availability, abnormal vesicle morphology, and α-synuclein accumulation. ATP supplementation fully restored vesicular function and alleviated dopamine-related pathologies in diseased neurons.
The implications
This ATP-sensitive VMAT2 mechanism links loss of DJ-1 and mitochondrial dysfunction to dopamine oxidation and synaptic failure, revealing enhanced dopamine sequestration as a promising disease-modifying strategy. The human iPSC platform opens avenues for targeted therapies preserving synaptic vesicle integrity in PD.
Creating SyNergies
This work integrates expertise across SyNergy labs specializing in iPSC disease modeling, advanced proteomics, and state-of-the-art imaging. Our study therefore highlights how interdisciplinary neurodegeneration research accelerates translation. Key contributing SyNergy researchers include Wolfgang Wurst, Stefan Lichtenthaler, Martina Schifferer and Christian Behrends, whose combined expertise bridges mechanism, modeling, and intervention.
