Rab27b Promotes Lysosomal Function and Alpha-Synuclein Clearance in Neurons.

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Medicine

Background:

• Alpha-synuclein aggregation is central to synucleinopathies like Parkinson's disease.
• The mechanisms driving alpha-synuclein propagation and aggregation remain unclear.
• Rab27b, a small GTPase, is elevated in Parkinson's disease and dementia with Lewy bodies.

Purpose of the Study:

• To investigate the role of Rab27b in neuronal lysosomal processing and alpha-synuclein clearance.
• To determine if Rab27b impacts alpha-synuclein aggregation in neuronal models.
• To explore Rab27b as a potential therapeutic target for synucleinopathies.

Main Methods:

• Utilized an alpha-synuclein-inducible neuronal model with Rab27b knockdown.
• Examined primary neuronal cultures and brain lysates from Rab27b knockout mice.
• Assessed lysosomal function, alpha-synuclein levels, aggregation, and Rab27b expression in human postmortem brain samples.

Main Results:

• Rab27b knockdown/knockout led to lysosomal dysfunction, impaired enzyme activity, and increased alpha-synuclein levels and aggregation.
• Altered acidic vesicle trafficking and lysosomal enzyme maturation/localization were observed.
• Rab27b overexpression enhanced lysosomal activity and reduced insoluble alpha-synuclein accumulation.
• Elevated Rab27b levels were found in incidental Lewy body disease subjects.

Conclusions:

• Rab27b plays a significant role in neuronal lysosomal function and alpha-synuclein clearance.
• Dysfunctional Rab27b contributes to alpha-synuclein aggregation, a hallmark of synucleinopathies.
• Rab27b represents a promising therapeutic target for Parkinson's disease and related disorders.