LRRK2 suppresses lysosome degradative activity in macrophages and microglia through MiT-TFE transcription factor...

Area of Science:

• Cell Biology
• Neuroscience
• Genetics

Background:

• Cells require optimal lysosome function for waste clearance, pathogen defense, and nutrient generation.
• Lysosomes are crucial organelles involved in cellular homeostasis and degradation.
• Dysfunctional lysosomes are implicated in various diseases, including neurodegenerative disorders.

Purpose of the Study:

• To investigate the role of Leucine-rich repeat kinase 2 (LRRK2) in regulating lysosome degradative activity.
• To elucidate the molecular mechanism by which LRRK2 controls lysosomal function.
• To explore the implications of LRRK2's role in lysosomal activity for Parkinson's disease pathogenesis.

Main Methods:

• Utilized cell models (macrophages and microglia) to study LRRK2 function.
• Manipulated LRRK2 levels and kinase activity (depletion, inhibition, and expression of Parkinson's disease mutant).
• Assessed lysosomal proteolytic activity, lysosomal hydrolase gene expression, and transcription factor localization.

Main Results:

• LRRK2 negatively regulates lysosome degradative activity through transcriptional control.
• Depletion or inhibition of LRRK2 enhanced lysosomal activity and hydrolase expression.
• The Parkinson's disease-associated LRRK2 G2019S mutant suppressed lysosomal activity and gene expression.
• MiT-TFE transcription factors (TFE3, TFEB, MITF) mediate LRRK2's control over lysosomal gene expression.
• LRRK2 affects the abundance and nuclear localization of MiT-TFE factors.

Conclusions:

• LRRK2 plays a significant role in controlling lysosome degradative activity.
• LRRK2 hyperactivity, as seen in Parkinson's disease, may increase disease risk by impairing lysosomal function.
• This study identifies a novel mechanism linking LRRK2 to lysosomal homeostasis and Parkinson's disease.