CLR01 protects dopaminergic neurons in vitro and in mouse models of Parkinson’s disease

Abstract

Parkinson’s disease (PD) affects millions of patients worldwide and is characterized by alpha-synuclein aggregation in dopamine neurons. Molecular tweezers have shown high potential as anti-aggregation agents targeting positively charged residues of proteins undergoing amyloidogenic processes. Here we report that the molecular tweezer CLR01 decreased aggregation and toxicity in induced pluripotent stem cell-derived dopaminergic cultures treated with PD brain protein extracts. In microfluidic devices CLR01 reduced alpha-synuclein aggregation in cell somas when axonal terminals were exposed to alpha-synuclein oligomers. We then tested CLR01 in vivo in a humanized alpha-synuclein overexpressing mouse model; mice treated at 12 months of age when motor defects are mild exhibited an improvement in motor defects and a decreased oligomeric alpha-synuclein burden. Finally, CLR01 reduced alpha-synuclein-associated pathology in mice injected with alpha-synuclein aggregates into the striatum or substantia nigra. Taken together, these results highlight CLR01 as a disease-modifying therapy for PD and support further clinical investigation.

The molecular tweezer CLR01 improves behavioral deficits and reduces tau pathology in P301S-tau transgenic mice

“…Our findings suggest that CLR01 is a promising drug candidate for the prevention and possibly treatment of AD and other tauopathies. The ability of CLR01 to target directly both Aβ and tau, and the fact that it can also inhibit formation of toxic assemblies by other amyloidogenic proteins involved in these diseases, such as α-synuclein [ 32 , 36 , 41 ] and TDP-43 (unpublished data), make it a particularly attractive compound. Our results demonstrate that peripherally administered CLR01 reduces tau hyperphosphorylation, oligomerization, and aggregate formation in the brain, as well as the formation of tau seeds.…”

“…Finally, the delivery of the drug via osmotic pumps, which was chosen for the same reasons, limits translatability to humans. As discussed above, recent studies have demonstrated that continuous administration is unnecessary and subcutaneous administration of CLR01 daily [ 38 , 40 ], or even twice a week can result in a robust therapeutic effect [ 41 ].…”

Lysine-selective molecular tweezers are cell-penetrant and concentrate in lysosomes

“…In the rst mouse study examining CLR01, 28-day subcutaneous administration of the compound in the triple-transgenic mouse model of AD 40 at 0.04 mg/Kg per day, which was estimated to yield low nM to high pM concentrations in the brain 9 , led to a robust reduction in both amyloid plaques and neuro brillary tangles 15 . Similarly, treatment of a mouse model of PD with the same dose of CLR01 administered subcutaneously twice weekly led to rescue of dopaminergic neurons and signi cant amelioration of motor de cits 14 . Part of the explanation is accumulation of the compound in the brain over time due to a brain-clearance rate that is much slower than the clearance of the compound from the blood 9 , yet a remaining question has been how MTs achieve su cient effective concentrations to prevent aberrant protein self-assembly and facilitate clearance of the rogue protein oligomers and aggregates in the context of a cell, where so many competing Lys/Arg binding sites are present.…”

“…However, in proteinopathies the cellular protein degradation and clearance mechanisms gradually become overwhelmed by the accumulating misfolded and aggregated proteins and eventually fail, leading to cell degeneration and death 39 . MTs have been shown to inhibit seeding and toxicity in cell culture 3,16 and reduce the accumulation of the offending proteins in multiple animal models 4,14,17,20,[22][23][24] . However, it has been unclear how very low concentrations of the compounds, particularly in the brain 9 , still yield substantial therapeutic effects.…”

Novel targeted therapies for Parkinson’s disease

“…The results in in-vitro studies and in two different transgenic rodent models showed decreased a-syn aggregation, reduced cortical synaptic accumulation and normalization of inflammatory and neuronal markers (Wrasidlo et al 2016 ). The molecular tweezer CLR01 inhibits α-syn aggregation through binding to lysine residues of α-syn that are crucial for its oligomerization, and it has shown efficacy, in terms of motor symptom improvement and decreased oligomeric α-syn burden, in transgenic mouse models of PD (Bengoa-Vergniory et al 2020 ).…”