Masanari Kato

Relationship between the tautomeric structures of curcumin derivatives and their Aβ-binding activities in the context of therapies for Alzheimer's disease

Curcumin, which can exist in an equilibrium between keto and enol tautomers, binds to beta-amyloid (Abeta) fibrils/aggregates. The aim of this study was to assess the relationship between the tautomeric structures of curcumin derivatives and their Abeta-binding activities. Curcumin derivatives with keto-enol tautomerism showed high levels of binding to Abeta aggregates but not to Abeta monomers. The binding activity of the keto form analogue of curcumin to Abeta aggregates was found to be much weaker than that of curcumin derivatives with keto-enol tautomerism. The color of a curcumin derivative with keto-enol tautomerism, which was substituted at the C-4 position, changed from yellow to orange within 30 min of being combined with Abeta aggregates in physiological buffer. This resulted from a remarkable increase in the enol form with extended conjugation of double bonds upon binding. These findings suggest that curcumin derivatives exist predominantly in the enol form during binding to Abeta aggregates, and that the enolization of curcumin derivatives is crucial for binding to Abeta aggregates. The keto-enol tautomerism of curcumin derivatives may be a novel target for the design of amyloid-binding agents that can be used both for therapy and for amyloid detection in Alzheimers disease.

Novel small molecule nonpeptide aminopeptidase n inhibitors with a cyclic imide skeleton.

A novel series of small molecule nonpeptide aminopeptidase N (APN) inhibitors with a N-phenylphthalimide or N-phenylhomophthalimide skeleton were prepared. Evaluation of their protease inhibitory activities revealed that (i) some N-phenylphthalimide analogs are potent APN inhibitors, but they are also inhibitors of another protease, dipeptidylpeptidase IV (DPP-IV), and (ii) some N-phenylhomophthalimide analogs, including 2-(2,6-diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1,3-dione (PIQ-22), are potent and specific inhibitors of APN without DPP-IV-inhibitory activity. The structure-activity relationship studies of N-phenylphthalimides and N-phenylhomophthalimides are reviewed. PIQ-22 showed potent tumor-cell invasion-inhibitory activity.

Nonpeptide small-molecular inhibitors of dipeptidyl peptidase IV: N-phenylphthalimide analogs

A novel series of nonpeptide small-molecular dipeptidyl peptidase IV (DPP-IV) inhibitors with an N-phenylphthalimide skeleton has been developed. Some of the compounds, including 4-amino-(2,6-dimethylphenyl)phthalimides (7), 4- and 5-hydroxy-(2,6-diethylphenyl)phthalimide (11 and 14), 4-hydroxy-(2,6-diisopropylphenyl)phthalimide (12), and thiocarbonyl analogs of (2,6-diisopropylphenyl)phthalimide and their 4,5,6,7-tetrafluorinated derivative (18, 19 and 20), were more potent than the well-known DPP-IV-specific inhibitor, Pro-boroPro (PBP). Among them, 18 was revealed to be a DPP-IV-specific inhibitor, while the others also showed inhibitory activity toward another peptidase, aminopeptidase N (APN).

Efficient delivery of antibody into living cells using a novel HVJ envelope vector system.

Introduction of antibodies which retain their function into cells using a simple and easy method would be very useful for study of the intracellular events in living cells. In this study, we developed a new method for intracellular delivery of antibody. It includes a combination of a novel IgG-capturing protein and hemagglutinating virus of Japan envelope (HVJ-E), an inactivated Sendai virus particle which can deliver a variety of molecules into mammalian cells via membrane-fusing activity. The IgG-capturing protein, which was molecularly designed to have two functions, was prepared as a fusion protein (ZZ-NP) of ZZ-dimer derived from an immunoglobulin-binding domain of protein A and nucleocapsid protein (NP), a part of the structural protein of HVJ. ZZ-NP was efficiently incorporated into the HVJ-E particle by treatment with detergent, and enhanced the incorporation of IgG. Moreover, fluorescence immunostaining revealed that the incorporated antibody was very efficiently introduced into living cells while retaining its function, i.e. anti-NPC (nuclear pore complex) monoclonal antibody was selectively located around cell nuclei. These findings suggest that this method is useful for intracellular delivery of antibody and for analysis of biological function of sub-cellular molecules in living cells.

A Novel Synthetic Anti-Acute Pancreatitis Agent, IS-741

A novel synthetic drug, IS-741, inhibited cell adhesion in vitro and neutrophil in vivo. Thus, IS-741 inhibited the magnification of pancreatic lesion as well as progression to multiple organ failure in acute pancreatitis models. Furthermore, IS-741 at identical plasma concentrations equally improved the survival rates in animals of various species with severe acute pancreatitis. Based on these observations, it was considered that IS-741 inhibited tissue destruction by neutrophil after inhibiting neutrophil infiltration into the pancreas or other important organs in acute pancreatitis. It was also considered that IS-741 demonstrated various anti-acute pancreatitis effects by interrupting a vicious cycle of inflammation. Therefore, IS-741 is expected to become a useful drug for treating acute pancreatitis and multiple organ failure in clinical settings.

IC-P1-061: Bezoxazol derivatives containing trifluoromethoxy-benzyl amino group for amyloid detection in APP transgenic mice using 19F magnetic resonance imaging

the application of support vector machines (SVM) to MRI for detection of a variety of disease states. To date, the application of SVM to structural MR scans for the purpose of AD diagnosis has not been demonstrated using pathologically confirmed cases for training data, nor to differentiate different forms of dementia. The aims of this study were to assess how successfully SVMs assigned individual diagnoses and to determine whether data-sets combined from multiple scanners and different centers could be used to obtain effective classification of scans. Methods: We used linear support vector machines to classify the grey matter segment of T1-weighted MR scans from pathologically proven AD patients and cognitively normal elderly individuals obtained from two centers with different scanning equipment. Furthermore, we sought to use these methods to differentiate scans between patients suffering from AD from those with pathologically proven frontotemporal lobar degeneration (FTLD). Results: Up to 96% of AD patients were correctly classified using whole brain grey matter images. Data from different centers were successfully combined achieving comparable results from the separate analyses. Importantly, data from one center could be used to train a support vector machine to accurately differentiate AD and normal aging scans obtained from another center with different subjects and different scanner equipment. Our method correctly assigned 89% of patients with post-mortem confirmed diagnosis of either AD or FTLD to their respective group. Conclusions: Support vector machines successfully separate patients with AD from healthy aging subjects. They also perform well in the differential diagnosis of two different forms of dementia. The method is robust and can be generalized across different centers. This suggests an important role for computer based diagnostic image analysis for clinical practice.

P2-089: Interaction of the brain tissues with trifluoromethoxy-benzylated ligands for amyloid detection using 19F magnetic resonance imaging

Tomone Amatsubo, Shigahiro Morikawa, Keiko Matsuda, Toshiro Inubushi, Makoto Urushitani, Hiroyasu Taguchi, Nobuaki Shirai, Koichi Hirao, Masanari Kato, Kyuya Morino, Hirohiko Kimura, Ichiro Nakano, Chikako Yoshida, Takashi Okada, Mitsuo Sano, Ikuo Tooyama, Shiga University of Medical Science, Otsu, Japan; JST Innovation Satellite Shiga, Otsu, Japan; Industrial Research Center of Shiga Prefecture, Ritto, Japan; Central Research Institute, Ishihara Sangyo Kaisya Ltd., Kusatsu, Japan. Contact e-mail: tomone@belle.shiga-med.ac.jp