Cross-seeding effects of amyloid β-protein and α-synuclein

Amyloid β-protein (Aβ) and α-synuclein (αS) are the primary components of amyloid plaques and Lewy bodies (LBs), respectively. Previous in vitro and in vivo studies have suggested that interactions between Aβ and αS are involved in the pathogenesis of Alzheimer\u27s disease and LB diseases. However, the seeding effects of their aggregates on their aggregation pathways are not completely clear. To investigate the cross-seeding effects of Aβ and αS, we examined how sonicated fibrils or cross-linked oligomers of Aβ40, Aβ42, and αS affected their aggregation pathways using thioflavin T(S) assay and electron microscopy. Fibrils and oligomers of Aβ40, Aβ42, and αS acted as seeds, and affected the aggregation pathways within and among species. The seeding effects of αS fibrils were higher than those of Aβ40 and Aβ42 fibrils in the Aβ40 and Aβ42 aggregation pathways, respectively. We showed that Aβ and αS acted as seeds and affected each other\u27s aggregation pathways in vitro, which may contribute to our understanding of the molecular mechanisms of interactions between Alzheimer\u27s disease and LB diseases pathologies. © 2012 The Authors

Familial Parkinson disease mutations influence α-Synuclein assembly

Lewy bodies composed of aggregates of α-Synuclein (αS) in the brain are the main histopathological features of Lewy body diseases (LBD) such as Parkinson\u27s disease and dementia with Lewy bodies. Mutations such as E46K, A30P and A53T in the αS gene cause autosomal dominant LBD in a number of kindreds. Although these mutations accelerate fibril formation, their precise effects at early stages of the αS aggregation process remain unknown. To answer this question, we examined the aggregation including monomer conformational dynamics and oligomerization of the E46K, A30P, A53T and A30P/A53T mutations and wild type (WT) using thioflavin S assay, circular dichroism spectroscopy, photo-induced cross-linking of unmodified proteins, electron microscopy, and atomic force microscopy. Relative to WT αS, E46K αS accelerated the kinetics of the secondary structure change and oligomerization, whereas A30P αS decelerated them. These effects were reflected in changes in average oligomer size. The mutant oligomers of E46K αS functioned as fibril seeds significantly more efficiently than those of WT αS, whereas the mutant oligomers of A30P αS were less efficient. Our results that mutations of familial LBD had opposite effects at early stages of αS assembly may provide new insight into the molecular mechanisms of LBD. © 2011 Elsevier Inc

Polyneuropathy caused by cobalt-chromium metallosis after total hip replacement

金沢大学附属病院神経内科Although metal intoxication after arthroplasty causes various symptoms, polyneuropathy has never been the focus of clinical investigation. We report the case of a 56-year-old woman with metal neuropathy. She had metallosis after hip arthroplasty with a cobalt-chromium alloy prosthesis. She developed progressive sensory disturbance, hearing loss, and hypothyroidism. Sural nerve biopsy indicated axonopathy. After exchange arthroplasty, blood levels of cobalt and chromium decreased, and her symptoms improved. Cobalt or chromium can cause axonopathy. © 2010 Wiley Periodicals, Inc

Coagulation and fibrinolysis abnormalities in familial amyloid polyneuropathy

Objective: Familial amyloid polyneuropathy (FAP) is an autosomal dominant form of hereditary amyloidosis. Several studies reported coagulation factor X deficiency and excessive fibrinolysis in immunoglobulin light chain amyloidosis. However, few have investigated coagulation and fibrinolysis in FAP. The objective of this study was to determine abnormalities in plasma biomarkers of coagulation and fibrinolysis in FAP. Methods: We prospectively recruited eight FAP patients with transthyretin mutations and ten age-matched control patients with other neuropathies in our university. We examined plasma biomarkers of coagulation and fibrinolysis including prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin/fibrinogen degradation products, D-dimer, α2-antiplasmin, antithrombin, plasminogen, thrombin-antithrombin complex, plasmin-α2-antiplasmin complex, prothrombin fragment 1+2, and coagulation factor X. The MannWhitney U test was performed for statistical comparisons between FAP and control groups. Results: FAP patients exhibited significantly decreased levels of coagulation factor X, plasminogen and α2-antiplasmin, and significantly increased levels of prothrombin fragment 1+2 compared to control patients. Conclusion: Our results indicate abnormalities of coagulation and fibrinolysis in FAP patients. © 2012 Informa UK, Ltd

CSF tau protein is a useful marker for effective treatment of superficial siderosis of the central nervous system: Two case reports

金沢大学附属病院神経内科We report two cases of superficial siderosis (SS) of the central nervous system (CNS), which is caused by chronic haemorrhaging into the subarachnoid space with haemosiderin deposition in the superficial portion of the CNS. Patient 1 had fluid collection in the spinal canal, which was reported as the source of the chronic bleeding. Patient 2 was bleeding from thickened dura at the level of the sacral vertebrae. Both of the patients had xanthochromic cerebrospinal fluid. We surgically repaired the sources of bleeding. Subsequently the cerebrospinal fluid (CSF) cleared and their symptoms were not aggravated for about 1 year. We measured several CSF markers of SS before and after surgery. Total tau protein (CSF-t-tau), phosphorylated tau protein (CSF-p-tau), iron (CSF-iron) and ferritin (CSF-ferritin) in the CSF were highly elevated at diagnosis. After surgery, the levels of CSF-t-tau and CSF-p-tau were markedly reduced while CSF-iron and CSF-ferritin had not decreased. It is suggested that CSF-t-tau and CSF-p-tau reflected the neural damage in SS and were useful to evaluate the effectiveness of SS therapies. © 2009 Elsevier B.V. All rights reserved

脳脊髄液中のアミロイドβオリゴマー化抑制物質解明と早期診断・治療法開発の展開

金沢大学医薬保健研究域医学系ヒト脳脊髄液のAmyloidβ蛋白に対するオリゴマー化抑制作用の原因物質の解明を行った。脳脊髄液を液体クロマトグラフィー(Size-exclusion column)で分注し、MS/MSで評価し、Angiotensin I、II、IIIの他、既知の蛋白の断片などの16種のペプチドの合成を行った。オリゴマー化の抑制力をPICUP法で評価し、AngiotensinI-IIIを含む11種のペプチドで抑制力をみとめ、Aβの線維化に対する抑制力をThioflavin T法を用いて評価し、9種のペプチドで抑制力を認めた。これらの蛋白はAlzheimer病の発生機序の究明、治療法の開発に寄与する。The purpose of this research was to identify inhibitors of amyloid β (Aβ) oligomerization in human cerebrospinal fluid (CSF). CSF was fractionated using centrifugation through a column and size-exclusion high-performance liquid chromatography. Two CSF fractions had inhibitory effects on Aβ oligomerization, as determined using tandem mass spectrometry. We identified 16 peptides with the desired activity: Angiotensins I, II, and III, and known fragments of these peptides. Using photo-induced cross-linking of unmodified proteins (PICUP), we identified 11 peptides with Aβ oligomerization inhibitory activity, including Angiotensins I-III. Thioflavin T fluorescence was used to identify 9 peptides with Aβ fibrillation inhibitory activity, including Angiotensins I-III. The discovery of these peptides contributes to the investigation of the mechanism underlying Alzheimer\u27s disease pathology and the development of therapeutic strategies for Alzheimer’s disease.研究課題/領域番号:16K19506, 研究期間(年度):2016-04-01 – 2018-03-3