University of Georgia, College of Pharmacy
Novel Allosteric Targeting Strategies to Inhibit LRRK2 in Parkinson's Disease using Constrained Peptides
SESSION 3: NOVEL MODULATORS OF BIOLOGY
Sunday, June 25, 2023, at 03:25 pm - 03:45 pm
The Leucine-Rich-Repeat-Kinase-2, LRRK2, protein is a multi-domain protein and missense mutations along the different domains of LRRK2 are the most common cause of genetically associated Parkinson’s Disease, PD. LRRK2 has a complex activation mechanism involving intra-molecular signaling, dimerization and protein-protein interactions.
It is not well understood how LRRK2 activity is regulated and how mutations in several domains of the protein alter its activity and function. Although symptomatic therapies are available for PD patients, there is currently no curative treatment for the disease. Several ATP-competitive kinase catalytic inhibitors have been developed for LRRK2, but many have side effects including kidney and lung toxicity and none of the inhibitors have yet received clinical approval for the treatment of PD.
As an alternative approach, we developed constrained peptides that either allosterically target LRRK2 itself or target a key downstream signaling pathway that is upregulated by pathogenic LRRK2. These are entirely new strategies to regulate LRRK2. As a strategy to disrupt LRRK2 activity, hydrocarbon-constrained "stapled" peptides were developed to target key intra- and intermolecular surfaces of the LRRK2 dimer as a novel strategy to downregulate LRRK2 function.
These cell-permeable compounds were found to inhibit LRRK2 activation and disease-related signaling in both wild-type and mutant forms of LRRK2. Further, unlike many ATP-competitive LRRK2 inhibitors, these peptide inhibitors did not induce LRRK2 mislocalization in cells. Overall, this work may demonstrate alternate, innovative approaches to allosterically inhibit/regulate altered LRRK2 activity.
Eileen Kennedy is the Georgia Athletic Association Professor, and Interim Department Head at the Department of Pharmacology at the University of Georgia. She earned her Ph.D. in Chemistry and Biochemistry at the University of California, San Diego 2005, and following Postdoctoral and Research Associate positions at Harvard University, came to the University of Georgia in 2010.
Research in the kennedy lab focuses on design of allosteric inhibitor compounds targeting kinase activation and signaling. The protein kinase superfamily comprises one of the largest gene families encoded in the human genome. A comprehensive understanding of kinase activity under normal and disease states is critical in order to identify targets for disease intervention. However, studying kinase signaling is inherently challenging since there are more than 500 kinases in the human genome, and as a result, there is significant crosstalk among multiple kinases for phosphorylation targets. Additionally, multiple isoforms exist for many kinases, thereby making it nearly impossible to address the question using genetic knockdowns/knockouts since other genes will compensate with altered expression levels.
To address this question, the Kennedy lab is developing novel chemical biology strategies to synthetically disrupt protein:protein interactions, PPIs, using chemically stabilized peptides. This methodology allows for the development of investigative tools that can be applied to elegantly and selectively manipulate protein-protein interactions that are involved in signaling pathways within a cellular environment. The long-term goal of the lab is to develop synthetic biologics that can be used to probe cell signaling events that are mediated by kinases. By inhibiting specific protein:protein interactions within a cellular environment, cancer-related cell signaling events can be studied in a temporal manner and highlight new strategies for therapeutic intervention. They are applying this strategy to study the AGC family of kinases as well as EGFR in breast and lung cancer models.