Targeted degradation of ⍺-synuclein aggregates in Parkinson’s disease using the AUTOTAC technology

Abstract

Background There are currently no disease-modifying therapeutics for Parkinson’s disease (PD). Although extensive efforts were undertaken to develop therapeutic approaches to delay the symptoms of PD, untreated α-synuclein (α-syn) aggregates cause cellular toxicity and stimulate further disease progression. PROTAC (Proteolysis-Targeting Chimera) has drawn attention as a therapeutic modality to target α-syn. However, no PROTACs have yet shown to selectively degrade α-syn aggregates mainly owing to the limited capacity of the proteasome to degrade aggregates, necessitating the development of novel approaches to fundamentally eliminate α-syn aggregates. Methods We employed AUTOTAC (Autophagy-Targeting Chimera), a macroautophagy-based targeted protein degradation (TPD) platform developed in our earlier studies. A series of AUTOTAC chemicals was synthesized as chimeras that bind both α-syn aggregates and p62/SQSTM1/Sequestosome-1, an autophagic receptor. The efficacy of Autotacs was evaluated to target α-syn aggregates to phagophores and subsequently lysosomes for hydrolysis via p62-dependent macroautophagy. The target engagement was monitored by oligomerization and localization of p62 and autophagic markers. The therapeutic efficacy to rescue PD symptoms was characterized in cultured cells and mice. The PK/PD (pharmacokinetics/pharmacodynamics) profiles were investigated to develop an oral drug for PD. Results ATC161 induced selective degradation of α-syn aggregates at DC50 of ~ 100 nM. No apparent degradation was observed with monomeric α-syn. ATC161 mediated the targeting of α-syn aggregates to p62 by binding the ZZ domain and accelerating p62 self-polymerization. These p62-cargo complexes were delivered to autophagic membranes for lysosomal degradation. In PD cellular models, ATC161 exhibited therapeutic efficacy to reduce cell-to-cell transmission of α-syn and to rescue cells from the damages in DNA and mitochondria. In PD mice established by injecting α-syn preformed fibrils (PFFs) into brain striata via stereotaxic surgery, oral administration of ATC161 at 10 mg/kg induced the degradation of α-syn aggregates and reduced their propagation. ATC161 also mitigated the associated glial inflammatory response and improved muscle strength and locomotive activity. Conclusion AUTOTAC provides a platform to develop drugs for PD. ATC161, an oral drug with excellent PK/PD profiles, induces selective degradation of α-syn aggregates in vitro and in vivo. We suggest that ATC161 is a disease-modifying drug that degrades the pathogenic cause of PD.

Targeted protein degradation directly engaging lysosomes or proteasomes

“…The AUTOTAC platform was utilised to facilitate the autophagic clearance of intracellular bacteria and α-synuclein. 82,90 As a part of their defence mechanisms, eukaryotic cells often rely on xenophagy, a type of selective autophagy, to capture intracellular pathogens, such as bacteria, protozoans, and viruses. 103,104 However, these intracellular pathogens have also evolved to evade or even inhibit cellular xenophagy to survive within their host cells.…”

“…90 Recently, Lee et al introduced new TBLs in the AUTOTAC toolkit, including baicalein (ATC162), a flavonoid compound that binds to α-synuclein, and resveratrol (ATC163), a phenol compound that binds to α-synuclein. 82 In the PD mouse model (oral administration, 10 mg kg −1 , 5 times per week, for 16 weeks), ATC161/Anle138b-F105 treatment reduced the number of α-synuclein aggregates in the brain, resulting in a significant delay in motor neuron degeneration. Similar to tau and α-synuclein, many target proteins tested with AUTOTAC degraders were either transiently or constitutively overexpressed.…”

Executive Summary of 2023 International Conference of the Korean Dementia Association (IC-KDA 2023): A Report From the Academic Committee of the Korean Dementia Association

“…Notably, these features extended beyond the injection site, mirroring the progressive spread observed in neurodegenerative diseases. 36 37 This protocol offered a model for neurodegenerative diseases, particularly the post-Aβ phase of AD. Unlike cross-seeding mechanisms requiring physical interactions between different aggregate proteins, he proposed a new mechanism that involves Aβ oligomers activating microglia, creating an inflammatory microenvironment that fosters the aggregation of downstream proteins like tau and α-synuclein.…”

Focusing on mitochondria in the brain: from biology to therapeutics

“…Latrepirdine improves neuropathology of AD and PD by stimulating autophagy to reduce neurodegeneration-related protein aggregates in animal models [ 204 , 403 – 405 ]. Recently, an autophagy-based targeted protein degradation platform has been developed to synthesize chemicals for degrading deposited proteins [ 406 ]. By this platform, ATC161 was identified as a promising chemical to treat PD, AD, progressive supranuclear palsy, and ALS [ 406 , 407 ].…”

“…Recently, an autophagy-based targeted protein degradation platform has been developed to synthesize chemicals for degrading deposited proteins [ 406 ]. By this platform, ATC161 was identified as a promising chemical to treat PD, AD, progressive supranuclear palsy, and ALS [ 406 , 407 ]. Moreover, UMI-77 induces myeloid leukemia 1-dependent degradation of damaged mitochondria (by mitophagy) and effectively reverses molecular and behavioral phenotypes of AD [ 408 ].…”