α‐synuclein conformational antibodies fused to penetratin are effective in models of Lewy body disease

Abstract

ObjectiveProgressive accumulation of α‐synuclein (α‐syn) has been associated with Parkinson's disease (PD) and Dementia with Lewy body (DLB). The mechanisms through which α‐syn leads to neurodegeneration are not completely clear; however, the formation of various oligomeric species have been proposed to play a role. Antibody therapy has shown effectiveness at reducing α‐syn accumulation in the central nervous system (CNS); however, most of these studies have been conducted utilizing antibodies that recognize both monomeric and higher molecular weight α‐syn. In this context, the main objective of this study was to investigate the efficacy of immunotherapy with single‐chain antibodies (scFVs) against specific conformational forms of α‐syn fused to a novel brain penetrating sequence.MethodWe screened various scFVs against α‐syn expressed from lentiviral vectors by intracerebral injections in an α‐syn tg model. The most effective scFVs were fused to the cell‐penetrating peptide penetratin to enhance transport across the blood–brain barrier, and lentiviral vectors were constructed and tested for efficacy following systemic delivery intraperitoneal into α‐syn tg mice.ResultTwo scFVs (D5 and 10H) selectively targeted different α‐syn oligomers and reduced the accumulation of α‐syn and ameliorated functional deficits when delivered late in disease development; however, only one of the antibodies (D5) was also effective when delivered early in disease development. These scFVs were also utilized in an enzyme‐linked immunosorbent assay (ELISA) assay to monitor the effects of immunotherapy on α‐syn oligomers in brain and plasma.InterpretationThe design and targeting of antibodies for specific species of α‐syn oligomers is crucial for therapeutic immunotherapy and might be of relevance for the treatment of Lewy body disease.

Differential effects of immunotherapy with antibodies targeting α-synuclein oligomers and fibrils in a transgenic model of synucleinopathy

“…These results are in agreement with our recent studies utilizing brain penetrant single chain antibodies that showed that clones capable of detecting α-syn oligomers were more effective at reducing synucleinopathy in tg when compared to single chain antibodies that had higher affinity for α-syn monomers (Spencer et al, 2014; Spencer et al, 2016). The advantage of the single chain antibodies in this study was the specificity and the ability to cross the blood brain barrier and as such they represent an important proof of principle.…”

“…Therefore, we developed single chain antibodies targeting α-syn oligomers and fibrils expressed from lentiviral vectors (Price et al, 2016; Spencer et al, 2014; Spencer et al, 2016). Although promising, there were some limitations, which led to the development of highly specific monoclonal antibodies differentially targeting oligomers versus fibrils.…”

TDP-43 protein variants as biomarkers in amyotrophic lateral sclerosis

“…We have previously shown that scFvs against alpha-synuclein variants associated with Parkinson’s disease have excellent therapeutic value [49, 50]. In a similar fashion, since our scFvs selectively bind ALS associated variants of TDP-43, in addition to diagnostic value, the scFvs may also have potential therapeutic value.…”

Targeting α-Synuclein as a therapy for Parkinson's disease: The battle begins

“…Gaining access to the brain with these large molecules is a potential limiting factor, particularly with passive immunization, and the clinical development program is further hindered because target validation is not currently possible. Methods to facilitate brain entry are currently being explored including the use of single‐chain antibodies that can be combined with a fusion protein . Other issues include the risks of inflammation, autoimmune reactions, and accelerating the disease process by inadvertently targeting α‐synuclein species that might be protective rather than toxic …”

“…Methods to facilitate brain entry are currently being explored including the use of single-chain antibodies that can be combined with a fusion protein. 32,33 Other issues include the risks of inflammation, autoimmune reactions, and accelerating the disease process by inadvertently targeting a-synuclein species that might be protective rather than toxic. 34 2.…”