Convergent molecular pathways to inherited Parkinson's disease

Area of Science:

• Neuroscience
• Genetics
• Cell Biology

Background:

• Pathogenic variants in Leucine-rich repeat kinase 2 (LRRK2) and Glucocerebrosidase 1 (GBA1) are high-risk genetic factors for Parkinson's disease.
• LRRK2 kinase activity and GBA1 enzyme activity are critical for cellular homeostasis, particularly in neurons and immune cells.
• Dysregulation of LRRK2 and GBA1 impacts lysosomal function, primary cilia stability, and neurotrophic factor production.

Purpose of the Study:

• To elucidate the cellular roles of LRRK2 and its link to GBA1 in Parkinson's disease pathogenesis.
• To investigate the therapeutic potential of targeting LRRK2 in a Parkinson's disease model.

Main Methods:

• Investigated LRRK2's role in phosphorylating Rab GTPases and its impact on cellular pathways.
• Examined the consequences of primary cilia loss and GBA1 deficiency on neuronal support mechanisms.
• Administered a LRRK2 inhibitor to LRRK2 mutant mice to assess its effects on cilia and neuroprotection.

Main Results:

• LRRK2 promotes exocytosis of lysosome-related organelles and regulates primary cilia formation.
• Loss of primary cilia or GBA1 deficiency impairs Hedgehog signaling, reducing neuroprotective factors.
• LRRK2 inhibition in mutant mice restored primary cilia and rescued neuroprotective factor production.

Conclusions:

• LRRK2 and GBA1 pathways are crucial for maintaining neuronal health in Parkinson's disease.
• Targeting LRRK2 kinase activity represents a promising therapeutic strategy for Parkinson's disease.
• Restoration of primary cilia and neurotrophic factors via LRRK2 inhibition offers a potential treatment avenue.