Single Chain Variable Fragments against β-Amyloid (Aβ) Can Inhibit Aβ Aggregation and Prevent Aβ-Induced Neurotoxicity

Neuropathologic and genetics studies as well as transgenic animal models have provided strong evidence linking misfolding and aggregation of ␣-synuclein to the progression of Parkinson disease (PD) and other related disorders. A growing body of evidence implicates various oligomeric forms of ␣-synuclein as the toxic species responsible for neurodegeneration and neuronal cell death. Although numerous different oligomeric forms of ␣-synuclein have been identified in vitro, it is not known which forms are involved in PD or how, when, and where different forms contribute to the progression of PD. Reagents that can interact with specific aggregate forms of ␣-synuclein would be very useful not only as tools to study how different aggregate forms affect cell function, but also as potential diagnostic and therapeutic agents for PD. Here we show that a single chain antibody fragment (syn-10H scFv) isolated from a phage display antibody library binds to a larger, later stage oligomeric form of ␣-synuclein than a previously reported oligomeric specific scFv isolated in our laboratory. The scFv described here inhibits aggregation of ␣-synuclein in vitro, blocks extracellular ␣-synuclein-induced toxicity in both undifferentiated and differentiated human neuroblastoma cell lines (SH-SY5Y), and specifically recognizes naturally occurring aggregates in PD but not in healthy human brain tissue.

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“…Aggregation of ␣-synuclein was measured in triplicate at various time points as described previously (32,46).…”

Section: Thioflavin T Aggregation Assaymentioning

confidence: 99%

Detecting Morphologically Distinct Oligomeric Forms of α-Synuclein

Emadi

Kasturirangan

Wang

et al. 2009

Journal of Biological Chemistry

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124

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“…Thus, reducing the level of Ab in the brain and inhibiting the aggregation of Ab are promising strategies for AD therapy [2]. Various compounds such as peptides [3,4], antioxidants [5,6], anti-inflammatory drugs [7], and antibodies [8,9] have been reported to have inhibitory effects on the aggregation of Ab. Furthermore, antibodies against Ab reduce the level of the protein in the brain of APP transgenic mice and inhibit neurotoxicity [10].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of the formation of amyloid β‐protein fibrils using biocompatible nanogels as artificial chaperones

et al. 2006

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The formation of fibrils by amyloid b-protein (Ab) is considered as a key step in the pathology of Alzheimer's disease (AD). Inhibiting the aggregation of Ab is a promising approach for AD therapy. In this study, we used biocompatible nanogels composed of a polysaccharide pullulan backbone with hydrophobic cholesterol moieties (cholesterol-bearing pullulan, CHP) as artificial chaperones to inhibit the formation of Ab-(1-42) fibrils with marked amyloidgenic activity and cytotoxicity. The CHPnanogels incorporated up to 6-8 Ab-(1-42) molecules per particle and induced a change in the conformation of Ab from a random coil to a-helix-or b-sheet-rich structure. This structure was stable even after a 24-h incubation at 37°C and the aggregation of Ab-(1-42) was suppressed. Furthermore, the dissociation of the nanogels caused by the addition of methylb-cyclodextrin released monomeric Ab molecules. Nanogels composed of amino-group-modified CHP (CHPNH 2 ) with positive charges under physiological conditions had a greater inhibitory effect than CHP-nanogels, suggesting the importance of electrostatic interactions between CHPNH 2 and Ab for inhibiting the formation of fibrils. In addition, CHPNH 2 nanogels protected PC12 cells from Ab toxicity.

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“…The presence of a scFv gene insert in a plasmid isolated from the selected clone was confirmed by PCR amplification and sequencing as described previously [11]. Production and purification of scFv were performed as indicated previously [12].…”

Section: Screening Of Positive Clones and Purification Of Scfv'smentioning

confidence: 99%

“…Antigen-scFv binding was performed using a BIAcore X biosensor (BIAcore Inc., Uppsala, Sweden) as described previously [11]. The concentrations of scFv's diluted serially which were applied to the Biacore were between 0.5 lM and 4.5 lM.…”

Section: Biacore Studymentioning

confidence: 99%

Conformation‐dependent single‐chain variable fragment antibodies specifically recognize beta‐amyloid oligomers

et al. 2009

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a b s t r a c tIncreasing evidence indicates that beta-amyloid (Ab) oligomers rather than monomers or fibrils are the major toxic agents that specifically inhibit synaptic plasticity and long-term potentiation (LTP) in Alzheimer's disease (AD). Neutralization of Ab oligomeric toxicity was found to reverse memory deficits. Here, we report four single-chain variable fragment (scFv) antibodies isolated from the naive human scFv library by phage display that specifically recognized Ab oligomers but not monomers and fibrils. These conformation-dependent scFv antibodies inhibit both Ab fibrillation and cytotoxicity and bind to the same type of eptitope displayed on the Ab oligomers. Such scFv antibodies specifically targeting toxic Ab oligomers may have potential therapeutic and diagnostic applications for AD.

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Single Chain Variable Fragments against β-Amyloid (Aβ) Can Inhibit Aβ Aggregation and Prevent Aβ-Induced Neurotoxicity

Cited by 110 publications

References 78 publications

Detecting Morphologically Distinct Oligomeric Forms of α-Synuclein

Detecting Morphologically Distinct Oligomeric Forms of α-Synuclein

Inhibition of the formation of amyloid β‐protein fibrils using biocompatible nanogels as artificial chaperones

Conformation‐dependent single‐chain variable fragment antibodies specifically recognize beta‐amyloid oligomers

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