Files
Abstract
Parkinson’s Disease (PD) is the second most common neurodegenerative disease affecting nearly 10 million people worldwide. Leucine Rich Repeat Kinase 2 (LRRK2) is the most common genetic contributor to disease pathogenesis, and LRRK2-mediated PD is indistinguishable from the sporadic form of the disease. Understanding how LRRK2-mediated PD functions could provide valuable insight into molecular pathways that are common between both familial and sporadic forms of the disease. Efforts to inhibit the catalytic activity of pathogenic LRRK2 have yielded effective and potent small molecule kinase inhibitors, yet these drugs have been limited in therapeutic potential due to adverse side effects. As an attempt to more subtly and specifically modulate LRRK2 activity, we have designed and developed stapled peptide allosteric inhibitors of LRRK2. Efforts to inhibit the catalytic activity of LRRK2 were previously limited to the kinase domain, yet protein-protein interactions have frequently been identified as largely involved in the disease-causing pathology of LRRK2. Specifically, LRRK2 dimerization, association with Fas Associated Death Domain (FADD), and localization with Rabs were all identified as upregulated with mutant-LRRK2 expression. We sought to disrupt these interactions using constrained peptides.
All-hydrocarbon stapled peptides bridge the gap between small molecules and biologics. By identifying peptide sequences that are major contributors to the binding site of interest, we can synthetically mimic these regions and reinforce the secondary structure with all-hydrocarbon stapled peptides. We designed distinct peptides for downregulating LRRK2 dimerization, disrupting LRRK2 association with FADD, and inhibiting LRRK2 recruitment by Rab proteins.
While these constrained peptides are distinct in nature, they all serve the common goal of allosterically regulating LRRK2 to downregulate its pathogenic activity in vitro. This work represents first-in-class allosteric inhibition of LRRK2, which can serve as a tool for researchers aiming to understand LRRK2 pathogenesis and highlights the long-term therapeutic potential of allosteric inhibition of LRRK2.