Inhibition of LRRK2 kinase activity promotes anterograde axonal transport and presynaptic targeting of α-synuclein

Acta Neuropathol Commun. 2021 Nov 8;9(1):180. doi: 10.1186/s40478-021-01283-7.

Abstract

Pathologic inclusions composed of α-synuclein called Lewy pathology are hallmarks of Parkinson's Disease (PD). Dominant inherited mutations in leucine rich repeat kinase 2 (LRRK2) are the most common genetic cause of PD. Lewy pathology is found in the majority of individuals with LRRK2-PD, particularly those with the G2019S-LRRK2 mutation. Lewy pathology in LRRK2-PD associates with increased non-motor symptoms such as cognitive deficits, anxiety, and orthostatic hypotension. Thus, understanding the relationship between LRRK2 and α-synuclein could be important for determining the mechanisms of non-motor symptoms. In PD models, expression of mutant LRRK2 reduces membrane localization of α-synuclein, and enhances formation of pathologic α-synuclein, particularly when synaptic activity is increased. α-Synuclein and LRRK2 both localize to the presynaptic terminal. LRRK2 plays a role in membrane traffic, including axonal transport, and therefore may influence α-synuclein synaptic localization. This study shows that LRRK2 kinase activity influences α-synuclein targeting to the presynaptic terminal. We used the selective LRRK2 kinase inhibitors, MLi-2 and PF-06685360 (PF-360) to determine the impact of reduced LRRK2 kinase activity on presynaptic localization of α-synuclein. Expansion microscopy (ExM) in primary hippocampal cultures and the mouse striatum, in vivo, was used to more precisely resolve the presynaptic localization of α-synuclein. Live imaging of axonal transport of α-synuclein-GFP was used to investigate the impact of LRRK2 kinase inhibition on α-synuclein axonal transport towards the presynaptic terminal. Reduced LRRK2 kinase activity increases α-synuclein overlap with presynaptic markers in primary neurons, and increases anterograde axonal transport of α-synuclein-GFP. In vivo, LRRK2 inhibition increases α-synuclein overlap with glutamatergic, cortico-striatal terminals, and dopaminergic nigral-striatal presynaptic terminals. The findings suggest that LRRK2 kinase activity plays a role in axonal transport, and presynaptic targeting of α-synuclein. These data provide potential mechanisms by which LRRK2-mediated perturbations of α-synuclein localization could cause pathology in both LRRK2-PD, and idiopathic PD.

Keywords: Axonal transport; Expansion microscopy; LRRK2; Parkinson’s disease; Presynaptic; Synapse; Trafficking; α-synuclein.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axonal Transport / physiology*
  • Enzyme Inhibitors
  • Female
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 / antagonists & inhibitors
  • Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Neurons / metabolism
  • Parkinson Disease / metabolism
  • Pregnancy
  • Primary Cell Culture
  • Receptors, Presynaptic / metabolism*
  • Vesicular Glutamate Transport Protein 1 / metabolism
  • alpha-Synuclein / metabolism*

Substances

  • Enzyme Inhibitors
  • Receptors, Presynaptic
  • Slc17a7 protein, mouse
  • Snca protein, mouse
  • Vesicular Glutamate Transport Protein 1
  • alpha-Synuclein
  • Leucine-Rich Repeat Serine-Threonine Protein Kinase-2
  • Lrrk2 protein, mouse