Development of Protein Like Polymer Therapeutics for Modulating the Nrf2/Keap1 Protein Protein Interaction in Neurodegenerative Diseases - PROJECT SUMMARY There is significant interest in developing therapeutics targeting the protein-protein interaction between nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and kelch-like ECH-associating protein 1 (Keap1) for neurodegenerative disease. A therapeutic that successfully and selectively inhibits Keap1/Nrf2 binding would enhance the cellular antioxidant response leading to a neuroprotective effect. Such inhibition of the Keap1/Nrf2 interaction could revolutionize our ability to treat multiple neurodegenerative diseases such as Alzheimer’s Disease. Inhibitory peptide therapeutics are of increasing interest but are limited in their pharmacokinetic profiles, cellular penetration, and efficacy. The proposed approach overcomes these challenges utilizing high-density brush polymer structures that are capable of engaging Keap1 and displacing the cellular protective transcription factor, Nrf2. These unique structures, termed protein-like polymers (PLPs), display specific Nrf2-derived peptide sequences around a hydrophobic synthetic polymer core. Compared to peptides alone, PLPs demonstrate resistance to proteolysis, improved pharmacokinetics, bioactivity and efficient cellular uptake. The PLP platform is proposed here for the development of two novel types of Keap1-inhibitors that overcome the current challenges limiting Keap1/Nrf2 targeted therapeutics. Keap1-targeting PLPs are the focus here due to the documented neuroprotective role of Nrf2 and the large unmet clinical need in neurodegenerative disease broadly. A key focus will be on the development of PLPs to competitively inhibit Keap1 and subsequently establish their efficacy as Nrf2 activators. Peptides identified via in silico modeling will be incorporated into PLPs and then evaluated by in vitro and in vivo analysis to determine bioactivity and pharmacokinetic properties. PLPs can be prepared with morphologies and molecular weights similar to proteins. Therefore, we will explore the effects of varying molecular weight, and thus polymer length, on Keap1-inhibition and bioactivity. In addition, PLPs can be prepared with multiple peptide-based domains. This multifunctionality combined with multivalency will be used to develop Nrf2 mimetics capable of spanning and selectively binding both Keap1 binding sites. Finally, the PLP platform will be used to design a class of Keap1-inhibitors capable of heterobifunctional binding, enabling targeted degradation of Keap1. These PLPs, designed as autophagy targeting chimeras (AUTACs), will selectively target Keap1 and shuttle the protein for degradation through the autophagy pathway. The proposed research plan seeks to address the current gaps facing translational therapeutics targeting the Keap1/Nrf2 interaction. The proposed research will be conducted under the guidance of Dr. Nathan Gianneschi and Dr. Jeffrey Johnson to establish technical skills in both materials science/chemistry and neurobiology respectively and with access to expertise and equipment at Northwestern University and the University of Wisconsin. The proposed training plan will develop the applicant into an independent researcher and foster clinical skills in preparation for a career as a physician scientist developing novel therapeutic platforms.
