Neuronal identity defines α-synuclein and tau toxicity

Area of Science:

• Neuroscience
• Genetics
• Cell Biology

Background:

• Pathogenic alpha-synuclein and tau proteins are key drivers of neurodegeneration, leading to neuronal loss.
• The reasons behind the preferential vulnerability of certain neuron types to these toxic proteins remain unclear.
• It is unknown if this vulnerability is an intrinsic cell property or due to increased protein expression.

Purpose of the Study:

• To investigate cell-type-specific expression of alpha-synuclein and tau in human brain datasets.
• To determine which cellular environments are most susceptible to alpha-synuclein or tau toxicity using fruit fly models.
• To identify intrinsic neuronal properties that confer vulnerability or resilience to neurodegeneration.

Main Methods:

• Analysis of cell-type-specific alpha-synuclein and tau expression in human brain datasets.
• Deep phenotyping and brain-wide single-cell RNA sequencing of over 200 live neuron types in Drosophila (fruit flies).
• Comparative analysis of vulnerable versus resilient neurons in Drosophila to predict human neuron susceptibility.

Main Results:

• Evidence of differential neuronal vulnerability to alpha-synuclein and tau toxicity, independent of protein expression levels.
• Identification of specific neuron subtypes in Drosophila with intrinsic susceptibility to these toxic proteins.
• Prediction of numerous human neuron subtypes with increased intrinsic susceptibility based on Drosophila findings.
• Discovery of synapse and calcium (Ca2+) homeostasis-related genes as modifiers of tau toxicity.

Conclusions:

• Neuronal vulnerability to pathogenic alpha-synuclein and tau is an intrinsic property, not solely dependent on expression levels.
• Drosophila models are effective for identifying intrinsic modifiers of neurodegeneration.
• Leveraging neuronal identity can uncover key factors influencing susceptibility to neurodegenerative diseases.