Autophagy dysfunction in iPSCs-derived neurons and midbrain organoids carrying a SNCA triplication

Area of Science:

• Neuroscience
• Cell Biology
• Genetics

Background:

• Parkinson's disease (PD) involves alpha-Synuclein aggregation and dopaminergic neuron loss, with no cure.
• Autophagy is crucial for clearing alpha-Synuclein, but its real-time dynamics are hard to study in human models.

Purpose of the Study:

• To assess real-time autophagy dynamics in human neuronal cultures and midbrain organoids (hMOs) from PD patients.
• To investigate the correlation between autophagy dysfunction, alpha-Synuclein pathology, and neuronal degeneration in PD models.

Main Methods:

• Utilized live-cell imaging and the LC3-Rosella dual-fluorescent reporter.
• Generated hMOs from induced pluripotent stem cells (iPSCs) of PD patients with a triplication of the alpha-Synuclein gene (3xSNCA).
• Quantified autolysosome dynamics, alpha-Synuclein levels, and electrophysiological activity.

Main Results:

• Early autophagy defects were observed in 3xSNCA neuronal cultures.
• In 3xSNCA hMOs, reduced autolysosome area, increased alpha-Synuclein (total and phosphorylated), and decreased electrophysiological activity were noted by 50 days of differentiation (DoD).
• Autophagy impairment worsened by 70 DoD, coinciding with dopaminergic neuron dysfunction.

Conclusions:

• Human iPSC-derived models effectively reveal autophagy dysfunction in Parkinson's disease.
• A temporal link exists between impaired autophagy, alpha-Synuclein pathology, and neurodegeneration in PD.