1
|
Nakagawa S, Kurokawa M, Kambara O, Takei T, Daidoji K, Naito A, Takita M, Kawamoto A, Hirose M, Tamura A. Structural Analyses of Designed α-Helix and β-Sheet Peptide Nanofibers Using Solid-State Nuclear Magnetic Resonance and Cryo-Electron Microscopy and Introduction of Structure-Based Metal-Responsive Properties. Int J Mol Sci 2024; 25:1111. [PMID: 38256184 PMCID: PMC10816960 DOI: 10.3390/ijms25021111] [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: 12/16/2023] [Revised: 01/11/2024] [Accepted: 01/14/2024] [Indexed: 01/24/2024] Open
Abstract
The 21-residue peptide α3, which is artificially designed and consists of three repeats of 7 residues, is known to rapidly assemble into the α-helix nanofiber. However, its molecular structure within the fiber has not yet been fully elucidated. Thus, we conducted a thorough investigation of the fiber's molecular structure using solid-state NMR and other techniques. The molecules were found to be primarily composed of the α-helix structure, with some regions near the C- and N-terminal adopting a 310-helix structure. Furthermore, it was discovered that β-sheet hydrogen bonds were formed between the molecules at both ends. These intermolecular interactions caused the molecules to assemble parallelly in the same direction, forming helical fibers. In contrast, we designed two molecules, CaRP2 and βKE, that can form β-sheet intermolecular hydrogen bonds using the entire molecule instead of just the ends. Cryo-EM and other measurements confirmed that the nanofibers formed in a cross β structure, albeit at a slow rate, with the formation times ranging from 1 to 42 days. To create peptide nanofibers that instantaneously respond to changes in the external environment, we designed several molecules (HDM1-3) based on α3 by introducing metal-binding sites. One of these molecules was found to be highly responsive to the addition of metal ions, inducing α-helix formation and simultaneously assembling into nanofibers. The nanofibers lost their structure upon removal of the metal ion. The change occurred promptly and was reversible, demonstrating that the intended level of responsiveness was attained.
Collapse
|
2
|
Kurokawa M, Ohtsu T, Chatani E, Tamura A. Hyper Thermostability and Liquid-Crystal-Like Properties of Designed α-Helical Peptide Nanofibers. J Phys Chem B 2023; 127:8331-8343. [PMID: 37751540 DOI: 10.1021/acs.jpcb.3c03833] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Structural and thermodynamic transitions of artificially designed α-helical nanofibers were investigated using eight peptide variants, including four peptides with amide-modified carboxyl termini (CB peptides) and four unmodified peptides (CF peptides). Temperature-dependent circular dichroism spectroscopy and differential scanning calorimetry showed that CB peptides exhibit thermostability up to 50 °C higher than CF peptides. As a result, one of the denaturation temperatures approached nearly 130 °C, which is exceptionally high for a biomacromolecule. Thermodynamic analysis and microscopy observations also showed that CB peptides undergo a thermal transition similar to the phase transition in liquid crystals. In addition, one of the peptides showed a sharp and highly cooperative transition with a small enthalpy change at around 25 °C, which was ascribed to a giga-bundle burst of the molecular assembly. These macroscopic changes in the thermostability and crystallinity of CB peptides may be attributed to an increased amphiphilicity of the molecule in the direction of the helix axis, originating from the microscopic modification of the carboxyl-terminus.
Collapse
|
3
|
Morita K, Nishimura K, Yamamoto S, Shimizu N, Yashiro T, Kawabata R, Aoi T, Tamura A, Maruyama T. In Situ Synthesis of an Anticancer Peptide Amphiphile Using Tyrosine Kinase Overexpressed in Cancer Cells. JACS AU 2022; 2:2023-2028. [PMID: 36186562 PMCID: PMC9516706 DOI: 10.1021/jacsau.2c00301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
Cell-selective killing using molecular self-assemblies is an emerging concept for cancer therapy. Reported molecular self-assemblies are triggered by hydrolysis of well-designed molecules inside or outside cancer cells. This hydrolysis can occur in cancer and normal cells because of the abundance of water in living systems. Here, we report the in situ synthesis of a self-assembling molecule using a tyrosine kinase overexpressed in cancer cells. We designed a tyrosine-containing peptide amphiphile (C16-E4Y) that is transformed into a phosphorylated peptide amphiphile (C16-E4pY) by the overexpressed tyrosine kinase. Phosphorylation of C16-E4Y promoted self-assembly to form nanofibers in cancer cells. C16-E4Y exhibited selective cytotoxicity toward cancer cells overexpressing the tyrosine kinase. Self-assembled C16-E4pY induced endoplasmic reticulum stress that caused apoptotic cell death. Animal experiments revealed that C16-E4Y has antitumor activity. These results show that an enzyme overexpressed in cancer cells is available for intracellular synthesis of an antitumor self-assembling drug that is cell-selective.
Collapse
|
4
|
Kanemitsu S, Morita K, Tominaga Y, Nishimura K, Yashiro T, Sakurai H, Yamamoto Y, Kurisaki I, Tanaka S, Matsui M, Ooya T, Tamura A, Maruyama T. Inhibition of Melittin Activity Using a Small Molecule with an Indole Ring. J Phys Chem B 2022; 126:5793-5802. [PMID: 35913127 DOI: 10.1021/acs.jpcb.2c03595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated d-amino acids as potential inhibitors targeting l-peptide toxins. Among the l- and d-amino acids tested, we found that d-tryptophan (d-Trp) acted as an inhibitor of melittin-induced hemolysis. We then evaluated various Trp derivatives and found that 5-chlorotryptamine (5CT) had the largest inhibitory effect on melittin. The indole ring, amino group, and steric hindrance of an inhibitor played important roles in the inhibition of melittin activity. Despite the small size and simple molecular structure of 5CT, its IC50 was approximately 13 μg/mL. Fluorescence quenching, circular dichroism measurements, and size-exclusion chromatography revealed that 5CT interacted with Trp19 in melittin and affected the formation of the melittin tetramer involved in hemolysis. Molecular dynamics simulation of melittin also indicated that the interaction of 5CT with Trp19 in melittin affected the formation of the tetramer.
Collapse
|
5
|
Yoshikawa Y, Yuzu K, Yamamoto N, Morishima K, Inoue R, Sugiyama M, Iwasaki T, So M, Goto Y, Tamura A, Chatani E. Pathway Dependence of the Formation and Development of Prefibrillar Aggregates in Insulin B Chain. Molecules 2022; 27:molecules27133964. [PMID: 35807211 PMCID: PMC9268647 DOI: 10.3390/molecules27133964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/18/2022] [Accepted: 06/19/2022] [Indexed: 11/16/2022] Open
Abstract
Amyloid fibrils have been an important subject as they are involved in the development of many amyloidoses and neurodegenerative diseases. The formation of amyloid fibrils is typically initiated by nucleation, whereas its exact mechanisms are largely unknown. With this situation, we have previously identified prefibrillar aggregates in the formation of insulin B chain amyloid fibrils, which have provided an insight into the mechanisms of protein assembly involved in nucleation. Here, we have investigated the formation of insulin B chain amyloid fibrils under different pH conditions to better understand amyloid nucleation mediated by prefibrillar aggregates. The B chain showed strong propensity to form amyloid fibrils over a wide pH range, and prefibrillar aggregates were formed under all examined conditions. In particular, different structures of amyloid fibrils were found at pH 5.2 and pH 8.7, making it possible to compare different pathways. Detailed investigations at pH 5.2 in comparison with those at pH 8.7 have suggested that the evolution of protofibril-like aggregates is a common mechanism. In addition, different processes of evolution of the prefibrillar aggregates have also been identified, suggesting that the nucleation processes diversify depending on the polymorphism of amyloid fibrils.
Collapse
|
6
|
Shimokawa M, Kanazu M, Saito R, Mori M, Tamura A, Okano Y, Fujita Y, Endo T, Motegi M, Takata S, Kita T, Sukoh N, Takenoyama M, Atagi S. 64P Clinical benefit of platinum doublet therapy for elderly patients with advanced non-small cell lung cancer: A prospective multicenter study of the national hospital organization in Japan. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.02.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
7
|
Yamamoto S, Nishimura K, Morita K, Kanemitsu S, Nishida Y, Morimoto T, Aoi T, Tamura A, Maruyama T. Microenvironment pH-Induced Selective Cell Death for Potential Cancer Therapy Using Nanofibrous Self-Assembly of a Peptide Amphiphile. Biomacromolecules 2021; 22:2524-2531. [PMID: 33960189 DOI: 10.1021/acs.biomac.1c00267] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Self-assembly of synthetic molecules has been drawing broad attention as a novel emerging approach in drug discovery. Here, we report selective cell death induced by a novel peptide amphiphile that self-assembles to form entangled nanofibers (hydrogel) based on intracellular pH (pHi). We found that a palmitoylated hexapeptide (C16-VVAEEE) formed a hydrogel below pH 7. The formation of the nanofibrous self-assembly was responsive to a small pH change around pH 7. The cytotoxicity of C16-VVAEEE was correlated with pHi of cells. Microscope observation demonstrated the self-assembly of C16-VVAEEE inside HEK293 cells. In vivo experiments revealed that the transcutaneous administration of C16-VVAEEE showed remarkable anti-tumor activity. This study proposes that distinct microenvironment inside living cells can be used as a trigger for the intracellular self-assembly of a peptide amphiphile, which provide a new clue to drug discovery.
Collapse
|
8
|
Sakurai H, Nishimura K, Yamamoto S, Maruyama T, Tamura A. Molecular Design of pH-Responsive Helix Peptides That Can Damage Tumor Cells Selectively. ACS APPLIED BIO MATERIALS 2021; 4:2442-2452. [DOI: 10.1021/acsabm.0c01407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
9
|
Narumoto O, Suzuki J, Takeda K, Tamura A, Nagai H, Matsui H. Rechallenge of voriconazole successfully tolerated after hepatic toxicity. Respir Med Case Rep 2020; 31:101191. [PMID: 32904036 PMCID: PMC7451706 DOI: 10.1016/j.rmcr.2020.101191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/30/2020] [Accepted: 08/08/2020] [Indexed: 12/24/2022] Open
Abstract
Infections caused by Aspergillus species are often life-threatening. Drugs effective for Aspergillus infection are limited. Voriconazole is one of the most important drugs, however, considerable portion of patients experience liver toxicity and have to stop the drug administration. We frequently experience liver toxicity even though the serum concentration of voriconazole is within the target range. Historically, in some life-threatening situations like tuberculosis, where a suitable alternative is unavailable, rechallenge has been attempted. However, there have been no report on the rechallenge of voriconazole. We report cases of successful re-administration of voriconazole after liver toxicity.
Collapse
|
10
|
Shimokawa M, Kanazu M, Saito R, Mori M, Tamura A, Okano Y, Fujita Y, Endo T, Motegi M, Takata S, Kita T, Sukoh N, Takenoyama M, Atagi S. 1375P Predicting chemotherapy toxicity in elderly patients with advanced non-small cell lung cancer: A prospective multicenter study of the national hospital organization in Japan. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.1689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
11
|
Kusaka K, Tamura A, Kozuki T, Koreeda Y, Kita T, Endo T, Shibayama T, Hatakeyama N, Miura M, Yamashita N, Takenoyama M. Randomized trial of prophylactic minocycline for erlotinib-associated skin rash in non-small cell lung cancer (PEARL trial). Ann Oncol 2019. [DOI: 10.1093/annonc/mdz437.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
12
|
Shimada M, Kanazu M, Shimokawa M, Saito R, Mori M, Tamura A, Okano Y, Fujita Y, Endo T, Motegi M, Takata S, Kita T, Sukoh N, Takenoyama M, Atagi S. Clinical outcomes in elderly patients with advanced non-small cell lung cancer: A prospective multicenter study of the National Hospital Organization in Japan. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz437.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
13
|
Kunimasa K, Ito K, Yamanaka T, Fujimoto D, Mori M, Maeno K, Tomomatsu K, Tamura A, Tanaka H, Watanabe S, Teraoka S, Hataji O, Suzuki K, Hontsu S, Hara S, Bessho A, Kubo A, Okuno M, Nakagawa K, Yamamoto N. The safety assessment of crizotinib and alectinib from real-world data of 840 ALK-inhibitor naïve patients with NSCLC harboring ALK-rearrangement (WJOG9516L). Ann Oncol 2019. [DOI: 10.1093/annonc/mdz260.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
Aida K, Nagao K, Kajitani K, Tamura A, Kobayashi T, Yukawa H, Kanazawa T, Kobayashi Y, Takahashi N, Nakagawa E, Ito H, Hayashi F, Makita T, Inada T, Tanaka M. P2623Measurement of liver fibrosis marker: type IV collagen 7S among patients with acute heart failure and its relationship with the Enhanced Liver Fibrosis (ELF) score. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.0946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Hemodynamic disturbance in acute heart failure (HF) can cause injury to extra-cardiac organs such as the liver. Organ injury in HF might evoke a profibrotic response, which could adversely affect the prognosis.
Methods
Among 189 patients with acute HF, we simultaneously determined the liver fibrosis marker, type IV collagen 7S (P4NP 7S) and the Enhanced Liver Fibrosis (ELF) Score consisting of tissue inhibitor of metalloproteinases 1 (TIMP-1), amino-terminal propeptide of type III procollagen (PIIINP) and hyaluronic acid (HA) on admission and at discharge.
Results
During hospitalization, P4NP 7S and ELF score significantly decreased from 7.1 ng/mL to 6.1 ng/mL (P<0.001) and 10.39 to 10.13 (P<0.001), respectively. P4NP 7S and ELF score were correlated with each other on admission (r=0.4, P<0.001) and at discharge (r=0.4, P<0.001). %Change of (Δ) P4NP 7S during hospitalization was correlated with ΔBNP and ΔELF score (r=0.3, P<0.001 and r=0.4, P<0.001, respectively). Among the components of ELF score, PIIINP and HA were correlated with P4NP 7S on admission (r=0.5, P<0.001 and r=0.3, P<0.001, respectively) and at discharge (r=0.4, P<0.001 and r=0.3, P<0.001, respectively). ΔP4NP 7S was also correlated with ΔTIMP-1, ΔPIIINP and ΔHA (r=0.3, P<0.001, r=0.4, P<0.001 and r=0.3, P<0.001, respectively). Each patient was followed up up to 365 days after discharge. 69 patients died or were hospitalized for HF. When the patients were divided into two groups according to the median value of each marker at discharge, the cumulative 1-year incidences of all cause death or HF hospitalization were 32.0% and 45.5% in P4NP 7S-low and P4NP 7S-high group, respectively (log-rank P=0.051) and 43.2% and 34.9% in ELF score-low and ELF score-high group, respectively (log-rank P=0.44). After adjustment by the clinically relevant factors including age, sex, hemoglobin, sodium and left ventricular ejection fraction, P4NP 7S showed independent prognostic value (adjusted hazard ratio: 1.12, P=0.02), while ELF score did not (adjusted hazard ratio: 1.04, P=0.79).
Conclusion
Parallel elevation of P4NP 7S and ELF score were documented during acute phase of HF. P4NP 7S at discharge may identify patients at high risk for subsequent HF related events.
Collapse
|
15
|
Kanazu M, Shimokawa M, Saito R, Mori M, Tamura A, Okano Y, Fujita Y, Endo T, Motegi M, Takata S, Kita T, Sukoh N, Takenoyama M, Atagi S. Predicting chemotherapy toxicity in elderly patients with advanced non-small cell lung cancer: A prospective multicenter study of the National Hospital Organization in Japan. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz260.093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
16
|
Yamamoto N, Akai T, Inoue R, Sugiyama M, Tamura A, Chatani E. Structural Insights into the Inhibition of Amyloid Fibril Formation by Fibrinogen via Interaction with Prefibrillar Intermediates. Biochemistry 2019; 58:2769-2781. [DOI: 10.1021/acs.biochem.9b00439] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
17
|
Koyama R, Udagawa H, Sugiyama E, Komuta K, Mori M, Yokoyama T, Sasaki T, Saito H, Ishida H, Nakagawa H, Sekine A, Tamura A, Shingyoji M, Mizuno K, Nakamura A, Kinoshita A, Yamanaka T, Goto K. Randomized phase II study comparing cisplatin + pemetrexed + bevacizumab with carboplatin + paclitaxel + bevacizumab in treatment-naïve advanced non-squamous non-small cell lung cancer (CLEAR study). Ann Oncol 2018. [DOI: 10.1093/annonc/mdy292.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
18
|
Tamura A, Nagao K, Sowa N, Nishiga M, Horie T, Ono K, Inada T, Tanaka M. P882Circulating markers of collagen I, III and IV turnover in patients with dilated cardiomyopathy: time-course change and relationships with myocardial collagen expression. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.p882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
19
|
Suzuki K, Akasaka K, Otsudo T, Mizoguchi Y, Ono K, Tamura A, Hattori H, Hasebe Y, Takei K, Yamamoto M, Hall T. Functional movement screen score and baseball performance in Japanese high school baseball players after corrective exercises. Ann Phys Rehabil Med 2018. [DOI: 10.1016/j.rehab.2018.05.1084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
20
|
Ono K, Akasaka K, Otsudo T, Mizoguchi Y, Suzuki K, Tamura A, Hattori H, Hasebe Y, Takei K, Yamamoto M, Hall T. Effects of neuromuscular training on ankle sprain in junior high school basketball players. Ann Phys Rehabil Med 2018. [DOI: 10.1016/j.rehab.2018.05.1075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
21
|
Akasaka K, Hasebe Y, Otsudo T, Hattori H, Tamura A. The effect of nordic hamstring exercise on preventing hamstrings injury on hamstring injury rate and time-loss injury rate in high school soccer players in Japan. Ann Phys Rehabil Med 2018. [DOI: 10.1016/j.rehab.2018.05.1082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
22
|
Yamaga K, Tokumasu R, Yamamoto A, Tamura A, Katayama I, Murota H, Tsukita S. 1319 Claudin-1 and -3 maintain proper hair follicle structure and regulate telogen effluvium. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.1336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
23
|
Yamamoto N, Tsuhara S, Tamura A, Chatani E. A specific form of prefibrillar aggregates that functions as a precursor of amyloid nucleation. Sci Rep 2018; 8:62. [PMID: 29311640 PMCID: PMC5758805 DOI: 10.1038/s41598-017-18390-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/11/2017] [Indexed: 11/29/2022] Open
Abstract
Non-fibrillar protein aggregates that appear in the earlier stages of amyloid fibril formation are sometimes considered to play a key role in amyloid nucleation; however, the structural features of these aggregates currently remain unclear. We herein identified a characteristic pathway of fibril formation by human insulin B chain, in which two major species of prefibrillar aggregates were identified. Based on the time-resolved tracking of this pathway with far-UV circular dichroism (CD) spectroscopy, dynamic light scattering (DLS), and 1H-NMR spectroscopy, the first prefibrillar aggregate with a hydrodynamic diameter of approximately 70 nm accumulated concomitantly with the formation of a β-sheet structure, and the size further evolved to 130 nm with an additional structural development. These prefibrillar aggregates were metastable and survived at least 24 hours as long as they were maintained under quiescent conditions. The energy barrier for nucleation was overcome by shaking or even by applying a single short ultrasonic pulse. Furthermore, an investigation where nucleation efficiency was monitored by fibrillation rates with varying the timing of the ultrasonic-pulse treatment revealed that the second prefibrillar aggregate specifically produced amyloid nuclei. These results suggest that the second form of the prefibrillar aggregates acts as a direct precursor for the amyloid nucleation.
Collapse
|
24
|
Takezawa H, Katsumori T, Tamura A, Fujii A, Goto Y, Yokoya S, Oka H, Hashimoto Y, Hino A. Two neuro-interventionists treated twice or more patients than one neuro-interventionist did. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.3118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
25
|
Kuriyama N, Ihara M, Koyama T, Mizuno T, Ozaki E, Kondo M, Tokuda T, Tamura A, Kazuo T, Nakagawa M, Watanabe Y. Vasoactive mid-regional pro-adrenomedullin is associated with cognitive decline accompa-nying deep white matter lesions in the brain: A longitudinal brain MRI study. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|