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Ohgita T, Sakai K, Fukui N, Namba N, Nakano M, Kiguchi Y, Morita I, Oyama H, Yamaki K, Nagao K, Kobayashi N, Saito H. Generation of novel anti-apoE monoclonal antibodies that selectively recognize apoE isoforms. FEBS Lett 2024; 598:902-914. [PMID: 38529702 DOI: 10.1002/1873-3468.14858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 03/27/2024]
Abstract
Apolipoprotein E (apoE) is a regulator of lipid metabolism, cholesterol transport, and the clearance and aggregation of amyloid β in the brain. The three human apoE isoforms apoE2, apoE3, and apoE4 only differ in one or two residues. Nevertheless, the functions highly depend on the isoform types and lipidated states. Here, we generated novel anti-apoE monoclonal antibodies (mAbs) and obtained an apoE4-selective mAb whose epitope is within residues 110-117. ELISA and bio-layer interferometry measurements demonstrated that the dissociation constants of mAbs are within the nanomolar range. Using the generated antibodies, we successfully constructed sandwich ELISA systems, which can detect all apoE isoforms or selectively detect apoE4. These results suggest the usability of the generated anti-apoE mAbs for selective detection of apoE isoforms.
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Affiliation(s)
- Takashi Ohgita
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
- Center for Instrumental Analysis, Kyoto Pharmaceutical University, Japan
| | - Koto Sakai
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
| | - Nodoka Fukui
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
| | - Norihiro Namba
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
| | - Miyu Nakano
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
| | - Yuki Kiguchi
- Laboratory of Bioanalytical Chemistry, Kobe Pharmaceutical University, Japan
| | - Izumi Morita
- Laboratory of Bioanalytical Chemistry, Kobe Pharmaceutical University, Japan
| | - Hiroyuki Oyama
- Laboratory of Bioanalytical Chemistry, Kobe Pharmaceutical University, Japan
| | - Kouya Yamaki
- Laboratory of Pharmacology, Kobe Pharmaceutical University, Japan
| | - Kohjiro Nagao
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
| | - Norihiro Kobayashi
- Laboratory of Bioanalytical Chemistry, Kobe Pharmaceutical University, Japan
| | - Hiroyuki Saito
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Japan
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Ohgita T, Kono H, Namba N, Saito H. Physicochemical mechanisms of aggregation and fibril formation of α-synuclein and apolipoprotein A-I. Biophys Physicobiol 2023; 21:e210005. [PMID: 38803339 PMCID: PMC11128303 DOI: 10.2142/biophysico.bppb-v21.0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/28/2023] [Indexed: 05/29/2024] Open
Abstract
Deposition and accumulation of amyloid fibrils is a hallmark of a group of diseases called amyloidosis and neurodegenerative disorders. Although polypeptides potentially have a fibril-forming propensity, native proteins have evolved into proper functional conformations to avoid aggregation and fibril formation. Understanding the mechanism for regulation of fibril formation of native proteins provides clues for the rational design of molecules for inhibiting fibril formation. Although fibril formation is a complex multistep reaction, experimentally obtained fibril formation curves can be fitted with the Finke-Watzky (F-W) two-step model for homogeneous nucleation followed by autocatalytic fibril growth. The resultant F-W rate constants for nucleation and fibril formation provide information on the chemical kinetics of fibril formation. Using the F-W two-step model analysis, we investigated the physicochemical mechanisms of fibril formation of a Parkinson's disease protein α-synuclein (αS) and a systemic amyloidosis protein apolipoprotein A-I (apoA-I). The results indicate that the C-terminal region of αS enthalpically and entropically suppresses nucleation through the intramolecular interaction with the N-terminal region and the intermolecular interaction with existing fibrils. In contrast, the nucleation of the N-terminal fragment of apoA-I is entropically driven likely due to dehydration of large hydrophobic segments in the molecule. Based on our recent findings, we discuss the similarity and difference of the fibril formation mechanisms of αS and the N-terminal fragment of apoA-I from the physicochemical viewpoints.
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Affiliation(s)
- Takashi Ohgita
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
- Center for Instrumental Analysis, Kyoto Pharmaceutical University, Kyoto 607-8412, Japan
| | - Hiroki Kono
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Norihiro Namba
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Hiroyuki Saito
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
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Ohgita T, Kono H, Morita I, Oyama H, Shimanouchi T, Kobayashi N, Saito H. Intramolecular interaction kinetically regulates fibril formation by human and mouse α-synuclein. Sci Rep 2023; 13:10885. [PMID: 37407638 DOI: 10.1038/s41598-023-38070-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/02/2023] [Indexed: 07/07/2023] Open
Abstract
Regulation of α-synuclein (αS) fibril formation is a potent therapeutic strategy for αS-related neurodegenerative disorders. αS, an intrinsically disordered 140-residue intraneural protein, comprises positively charged N-terminal, hydrophobic non-amyloid β component (NAC), and negatively charged C-terminal regions. Although mouse and human αS share 95% sequence identity, mouse αS forms amyloid fibrils faster than human αS. To evaluate the kinetic regulation of αS fibrillation, we examined the effects of mismatched residues in human and mouse αS on fibril formation and intramolecular interactions. Thioflavin T fluorescence assay using domain-swapped or C-terminal-truncated αS variants revealed that mouse αS exhibited higher nucleation and fibril elongation than human αS. In mouse αS, S87N substitution in the NAC region rather than A53T substitution is dominant for enhanced fibril formation. Fӧrester resonance energy transfer analysis demonstrated that the intramolecular interaction of the C-terminal region with the N-terminal and NAC regions observed in human αS is perturbed in mouse αS. In mouse αS, S87N substitution is responsible for the perturbed interaction. These results indicate that the interaction of the C-terminal region with the N-terminal and NAC regions suppresses αS fibril formation and that the human-to-mouse S87N substitution in the NAC region accelerates αS fibril formation by perturbing intramolecular interaction.
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Affiliation(s)
- Takashi Ohgita
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan.
| | - Hiroki Kono
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Izumi Morita
- Department of Bioanalytical Chemistry, Kobe Pharmaceutical University, 4-19-1 Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Hiroyuki Oyama
- Department of Bioanalytical Chemistry, Kobe Pharmaceutical University, 4-19-1 Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Toshinori Shimanouchi
- Graduate School of Environmental and Life Science, Okayama University, Okayama, 700-8530, Japan
| | - Norihiro Kobayashi
- Department of Bioanalytical Chemistry, Kobe Pharmaceutical University, 4-19-1 Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Hiroyuki Saito
- Laboratory of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto, 607-8414, Japan
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Mechanisms of enhanced aggregation and fibril formation of Parkinson's disease-related variants of α-synuclein. Sci Rep 2022; 12:6770. [PMID: 35474118 PMCID: PMC9043213 DOI: 10.1038/s41598-022-10789-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 04/08/2022] [Indexed: 12/18/2022] Open
Abstract
Aggregation of α-synuclein (α-syn) into amyloid fibrils is closely associated with Parkinson’s disease (PD). Familial mutations or posttranslational truncations in α-syn are known as risk factor for PD. Here, we examined the effects of the PD-related A30P or A53T point mutation and C-terminal 123–140 or 104–140 truncation on the aggregating property of α-syn based on the kinetic and thermodynamic analyses. Thioflavin T fluorescence measurements indicated that A53T, Δ123‒140, and Δ104–140 variants aggregated faster than WT α-syn, in which the A53T mutation markedly increases nucleation rate whereas the Δ123‒140 or Δ104‒140 truncation significantly increases both nucleation and fibril elongation rates. Ultracentrifugation and western blotting analyses demonstrated that these mutations or truncations promote the conversion of monomer to aggregated forms of α-syn. Analysis of the dependence of aggregation reaction of α-syn variants on the monomer concentration suggested that the A53T mutation enhances conversion of monomers to amyloid nuclei whereas the C-terminal truncations, especially the Δ104–140, enhance autocatalytic aggregation on existing fibrils. In addition, thermodynamic analysis of the kinetics of nucleation and fibril elongation of α-syn variants indicated that both nucleation and fibril elongation of WT α-syn are enthalpically and entropically unfavorable. Interestingly, the unfavorable activation enthalpy of nucleation greatly decreases for the A53T and becomes reversed in sign for the C-terminally truncated variants. Taken together, our results indicate that the A53T mutation and the C-terminal truncation enhance α-syn aggregation by reducing unfavorable activation enthalpy of nucleation, and the C-terminal truncation further triggers the autocatalytic fibril elongation on the fibril surfaces.
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