平成20年 神経変性疾患研究部門(旧分子細胞学)

神経変性疾患研究部門の担当教授(坂口末廣)は、平成18 年度に分子細胞学部門の教授として着任し、その後当センターの改組に伴い、平成19年度から当部門を担当している。当部門では、プリオン蛋白(PrP)の正常機能の解明、プリオン病の分子病態の解明、プリオン病の予防・治療法の開発を中心テーマとして研究を進めている。なお、当部門の井上勲准教授は、以前から継続して個別の研究テーマのもとで独立して研究を行っているので、別途、自己点検・評価を依頼した。


プリオン蛋白の正常機能の解明

我々は、PrP-/- マウスを作成し、PrPの正常機能を解析してきた。その結果、PrPが小脳プルキンエ細胞の長期生存に重要であることを報告した(Nature, 1996; Lab Invest, 1999)。後に我々は、PrP遺伝子の下流に、PrPと非常に類似した分子(プリオン蛋白類似蛋白、PrPLP)の遺伝子を発見し(Cell Mol Neurobiol, 2000; Am J Pathol, 2000)、この遺伝子がPrP-/-マウスの脳内で異所性に過剰発現しプルキンエ細胞死をきたし、PrPはPrPLPの細胞毒性機能を阻害することでプルキンエ細胞の生存を維持していたことを明らかにした(BBRC, 2004)。また我々は、PrPのN末領域(アミノ酸23-88)にPrPLPの機能を抑制するのに重要な領域が存在することを明らかにした(JBC, 2003)。さらに我々は、PrPが脳虚血からの神経細胞の障害を緩和し、PrPLPは逆に増悪させることも報告した(Neurosci, 2005)。最近我々は、米国のHarris教授との共同研究により、PrPLPによるプルキンエ細胞死にはBaxが関与しないことを見出した(Am J Pathol, 2007)。また我々は、PrPLPの抑制に重要なPrPの領域をさらに解析し、その結果を報告した(JBC, 2008)。また最近、興味深いことに、PrPを過剰発現させるとp38 MAPキナーゼが活性化され細胞死が起こることを見出している(論文準備中)。今後、PrPの正常機能を分子レベルで解明していきたいと考えている。


プリオン病の病態解明

我々は、残念ながら世界で最初の報告とならなかったが、PrP-/-マウスがプリオンに感染しないことから、PrPがプリオンの複製に重要な分子であることを明らかにした(J Virol, 1995)。その後、プリオン感染マウス脳で特異的に発現が上昇する遺伝子を同定し、それらがプリオン病の病態に関与する可能性を示した(J Virol, 2000)。また、プリオンの生物学的性質が培養細胞に長期感染していても変化しないことを報告した(J Virol, 2005)。最近、産業医科大学の宮田准教授との共同研究で、様々な遺伝子のノックアウトマウスや、様々な領域の欠損PrPを発現するトランスジェニックマウスを用いて感染実験を行っており、今後これらの実験から新たな成果が出ることが期待される。


プリオン病の予防・治療法の開発

我々は、PrPに大腸菌の易熱性エンテロトキシン・サブユニットBを融合させると、PrPの粘膜免疫性が高まり、鼻粘膜投与によりPrP特異的IgGとIgAが産生されることを報告した(Vaccine, 2006)。また、ウシやヒツジ由来の異種のPrPをマウスに免疫すると、特異抗体価が上昇し、僅かであるが有意にプリオン感染を遅らせることが出来ることを見出した(Vaccine, 2007)。これらの結果は、PrPに対する特異抗体をさらに産生させることが出来れば、プリオン病の予防が出来るかもしれないことを示唆した。従って今後は、PrPに対する特異抗体をさらに産生させる方法について研究してきたいと考えている。


また我々は、プリオン蛋白に対する抗体を感染マウスの脳室内に直接投与すると、異常プリオン蛋白が減少することを見出した(未発表)。しかし、残念ながら、延命効果は認められなかった(未発表)。これらの結果は、抗体が生命維持に重要な部位まで到達できなかったためと考えられる。今後は、抗体の脳内デリバリーシステムの開発研究を進めていきたいと考えている。

 

業績
  1. Antagonistic roles of the N-terminal domain of prion protein to doppel
    Prion (in press) IF:-
    S. Sakaguchi
  2. Dominant-negative effects of the amino-terminal half of prion protein on neurotoxicity of PrP-like protein/doppel in mice
    J. Biol. Chem. 283(35), 24202-11 (2008) IF:5.581
    D. Yoshikawa, N. Yamaguchi, D. Ishibashi, H. Yamanaka, N. Okimura, Y. Yamaguchi, T. Mori, H. Miyata, K. Shigematsu, S. Katamine and S. Sakaguchi
  3. Prospects for Preventative Vaccines against Prion Diseases
    Protein Peptide Lett. (in press) IF:1.097
    S. Sakaguchi
  4. Cellular prion protein prevents brain damage after encephalomyocarditis virus infection in mice
    Arch. Virol. 153(6), 1007-1012 (2008) IF:1.839
    Y. Nasu-Nishimura, Y. Taniuchi, T. Nishimura, A. Sakudo, K. Nakajima, Y. Ano, K. Sugiura, S. Sakaguchi, S. Itohara and T. Onodera
  5. Recent development in therapeutics for prion diseases
    Expert Opin. Ther. Pat. 18(1), 35-59 (2008) IF:1.589
    S. Sakaguchi
  6. Molecular biology of prion protein and its first homologous protein
    J. Med. Invest. 54(3-4), 211-223 (2007) IF:-
    S. Sakaguchi
  7. Late-onset olfactory deficits and mitral cell loss in mice lacking prion protein with ectopic expression of Doppel
    Int. J. Mol. Med. 20(2), 169-176 (2007) IF:1.847
    CK. Kim, A. Sakudo, Y. Taniuchi, K. Shigematsu, CB. Kang, K. Saeki, Y. Matsumoto, S. Sakaguchi, S. Itohara and T. Onodera
  8. Reduced response of splenocytes after mitogen-stimulation in the prion protein (PrP) gene-deficient mouse: PrPLP/Doppel production and cerebral degeneration
    Biochem. Bioph. Res. Co. 358, 469-474 (2007) IF:2.749
    CK. Kim, Y. Hirose, A. Sakudo, N. Takeyama, CB. Kang , Y. Taniuchi, Y. Matsumoto, S. Itohara, S. Sakaguchi, T. Onodera
  9. Doppel induces degeneration of cerebellar Purkinje cells independently of Bax
    Am. J. Pathol. 171(2), 599-607 (2007) IF:5.487
    J. Dong, A. Li, N. Yamaguchi, S. Sakaguchi and DA. Harris
  10. Serum withdrawal-induced apoptosis in Zrch I prion protein (PrP) gene-deficient neuronal cell line is suppressed by PrP, independent of Doppel
    Microbiol. Immunol. 51(4), 457-66 (2007) IF:1.295
    T. Nishimura, A. Sakudo, Y. Hashiyama, A. Yachi, K. Saeki, Y. Matsumoto, M. Ogawa, S. Sakaguchi, S. Itohara and T. Onodera
  11. Immunohistochemical characterization of cell types expressing the cellular prion protein in the small intestine of cattle and mice
    Histochem. Cell Biol. 127(3), 291-301 (2007) IF:2.893
    K. Miyazawa, T. Kanaya, S. Tanaka, I. Takakura, K. Watanabe, S. Ohwada, H. Kitazawa, MT. Rose, S. Sakaguchi, S. Katamine, T. Yamaguchi and H. Aso
  12. Recent developments in mucosal vaccines against prion diseases
    Expert Rev. Vaccines 6(1), 75-85 (2007) IF:2.111
    S. Sakaguchi (corresponding author) and T. Arakawa
  13. Immunization with recombinant bovine but not mouse prion protein delays the onset of disease in mice inoculated with a mouse-adapted prion
    Vaccine 25(6), 985-992 (2007) IF:3.377
    D. Ishibashi, H. Yamanaka, N. Yamaguchi, D. Yoshikawa, R. Nakamura, N. Okimura, Y. Yamaguchi, K. Shigematsu, S. Katamine and S. Sakaguchi (corresponding author)
  14. Newly established in vitro system with fluorescent proteins shows that abnormal expression of downstream prion protein-like protein in mice is probably due to functional disconnection between splicing and 3’ formation of prion protein pre-mRNA
    Gene 386, 139-146 (2007) IF:2.871
    D. Yoshikawa, J. Kopacek, N. Yamaguchi, D. Ishibashi, H. Yamanaka, Y. Yamaguchi, S. Katamine and S. Sakaguchi
  15. Tgat oncoprotein functions as a inhibitor of RECK by association of the unique C-terminal region
    Biochem. Bioph. Res. Co. 355 (4), 937-43 (2007) IF:2.749
    T. Mori, R. Moriuchi, E. Okazaki, K. Yamada and S. Katamine
  16. Tgat, a Rho-specific guanine nucleotide exchange factor, activates NF-kappaB via physical association with IkappaB kinase complexes
    Biochem. Bioph. Res. Co. 355 (1), 269-74 (2007) IF:2.749
    K. Yamada, R. Moriuchi, T. Mori, E. Okazaki, T. Kohno, T. Nagayasu, T. Matsuyama and S. Katamine
  17. Anti-gp210 and anti-centromere antibodies are different risk factors for the progression of primary biliary cirrhosis
    Hepatology 45 (1), 118-27 (2007) IF:10.734
    M. Nakamura, H. Kondo, T. Mori, A. Komori, M. Matsuyama, M. Ito, Y. Takii, M. Koyabu, T. Yokoyama, K. Migita, M. Daikoku, S. Abiru, H. Yatsuhashi, E. Takezaki, N. Masaki, K. Sugi, K. Honda, H. Adachi, H. Nishi, Y. Watanabe, Y. Nakamura, M. Shimada, T. Komatsu, A. Saito, T. Saoshiro, H. Harada, T. Sodeyama, S. Hayashi, A. Masumoto, T. Sando, T. Yamamoto, H. Sakai, M. Kobayashi, T. Muro, M. Koga., Z. Shums, GL. Norman and H. Ishibashi
  18. Human intrahepatic biliary epithelial cells function in innate immunity by producing IL-6 and IL-8 via the TLR4-NF-kappaB and -MAPK signaling pathways
    Liver Int. 26 (4), 467-76 (2006) IF:2.559
    T. Yokoyama, A. Komori, M. Nakamura, Y. Takii, T. Kamihira, S. Shimoda, T. Mori, S. Fujiwara, M. Koyabu, K. Taniguchi, H. Fujioka, K. Migita, H. Yatsuhashi and H. Ishibashi
  19. Increased expression of nuclear envelope gp210 antigen in small bile ducts in primary biliary cirrhosis
    J. Autoimmun. 26 (2), 138-45 (2006) IF:3.391
    M. Nakamura, Y. Takii, M. Ito, A. Komori, T. Yokoyama, Y. Shimizu-Yoshida, M. Koyabu, M. Matsuyama, T. Mori, T. Kamihira, M. Daikoku, K. Migita, H. Yatsuhashi, N. Nozaki, S. Shimoda and H. Ishibashi
  20. Immunosuppressant FK506 inhibits matrix metalloproteinase-9 induction in TNF-alpha-stimulated human hepatic stellate cells
    Life Sci. 78 (21), 2510-2515 (2006) IF:2.257
    K. Migita, Y. Maeda, S. Abiru, M. Nakamura, A. Komori, T. Yokoyama, Y. Takii, T. Mori, H. Yatsuhashi, K. Eguchi and H. Ishibashi
  21. Identification of NADH dehydrogenase 1 alpha subcomplex 5 capable to transform murine fibroblasts and overexpressed in human cervical carcinoma cell lines
    Biochem. Bioph. Res. Co. 339(3), 852-857 (2006) IF:2.749
    T. Shimada, R. Moriuchi, T. Mori, K. Yamada, T. Ishimaru and S. Katamine
  22. Surface plasmon resonance analysis for the screening of ant-prion compounds
    Biol. Pharm. Bull. 29(5), 927-932 (2006) IF:1.614

    S. Kawatake, Y. Nishimura, S. Sakaguchi, T. Iwaki and K. Doh-ura
  23. Enhanced mucosal immunogenicity of prion protein following fusion with B subunit of Escherichia coli heat-labile enterotoxin
    Vaccine 24, 2815-2823 (2006) IF:3.377
    H. Yamanaka, D. Ishibashi, N. Yamaguchi, D. Yoshikawa, R. Nakamura, N. Okimura, T. Arakawa, T. Tsuji, S. Katamine and S. Sakaguchi (corresponding author)
  24. Female-specific neuroprotection against transient brain ischemia observed in mice devoid of prion protein is abolished by ectopic expression of prion protein-like protein
    Neuroscience 136, 281-287 (2005) IF:3.352
    Y. Sakurai-Yamashita, S. Sakaguchi (equal contributor), D. Yoshikawa, N. Okimura, Y. Masuda, S. Katamine and M. Niwa
  25. Biological and biochemical characteristics of prion strains conserved in persistently-infected cell cultures
    J. Virol. 79, 7104-7112 (2005) IF:5.332
    K. Arima, N. Nishida, S. Sakaguchi, K. Shigematsu, R. Atarashi, N. Yamaguchi, D. Yoshikawa, J. Yoon, K. Watanabe, N. Kobayashi, S. Mouillet-Richard, S. Lehmann and S. Katamine
  26. The absence of prion-like infectivity in mice expressing prion protein-like protein
    EXCLI Journal 3, 82-90 (2004) IF:-
    R. Atarashi, S. Sakaguchi (corresponding author, equal contributor), K. Shigematsu and S. Katamine
  27. Antagonistic roles of prion protein and prion protein-like protein in neurodegeneration
    Recent Research Developments in Experimental Medicine 1, 47-61 (2004) IF:-
    S. Sakaguchi
  28. Cellular prion protein regulates intracellular hydrogen peroxide level and prevents copper-induced apoptosis
    Biochem. Bioph. Res. Co. 323, 218-222 (2004) IF:2.749
    T. Nishimura, A. Sakudo, I. Nakamura, D. Lee, Y. Taniuchi, K. Saeki, Y. Matsumoto, M. Ogawa, S. Sakaguchi, S. Itohara and T. Onodera
  29. Doppel-induced Purkinje cell death is stoichiometrically abrogated by prion protein
    Biochem. Bioph. Res. Co. 319, 1247-1252 (2004) IF:2.749
    N. Yamaguchi, S. Sakaguchi (corresponding author), K. Shigematsu, N. Okimura and S. Katamine
  30. Prion protein suppresses perturbation of cellular copper homeostasis under oxidative conditions
    Biochem. Bioph. Res. Co. 313, 845-850 (2004) IF:2.749
    A. Sakudo, D. Lee, E. Yoshimura, S. Nagasaka, K. Nitta, K. Saeki, Y. Matsumoto, S. Lehmann, S. Itohara, S. Sakaguchi and T. Onodera
  31. Cellular prion protein promotes Brucella infection into macrophages
    J. Exp. Med. 198, 5-17 (2003) IF:15.612
    M. Watarai, S. Kim, J. Erdenebaatar, S. Makino, M. Horiuchi, T. Shirahata, S. Sakaguchi and S. Katamine
  32. Deletion of N-terminal residues 23-88 from prion protein (PrP) abrogates the potential to rescue PrP-deficient mice from PrP-like protein/Doppel-induced neurodegeneration
    J. Biol. Chem. 278, 28944-28949 (2003) IF:5.581
    R. Atarashi, N. Nishida, K. Shigematsu, S. Goto, T. Kondo, S. Sakaguchi, and S. Katamine
  33. Similar target, different effects: late-onset ataxia and spatial learning in prion protein-deficient mouse lines
    Neurogenetics 3, 173-184 (2001) IF:4.281
    P. Valenti, A. Cozzio, N. Nishida, DP. Wolfer, S. Sakaguchi and HP. Lipp
  34. Abnormal activation of glial cells in the brains of prion protein-deficient mice ectopically expressing prion protein-like protein, PrPLP/Dpl
    Mol. Med. 7, 803-809 (2001) IF:2.078
    R. Atarashi, S. Sakaguchi (corresponding author), K. Shigematsu, K. Arima, N. Okimura, N. Yamaguchi, A. Li, J. Kopacek and S. Katamine
  35. PrP fragment 106-126 is toxic to cerebral endothelial cells expressing PrPC
    NeuroReport 11(17), 3931-3936 (2000) IF:2.163
    MA. Deli, S. Sakaguchi, R. Nakaoke, CS. Abraham, H. Takahata, J. Kopacek, K. Shigematsu, S. Katamine and M. Niwa
  36. Physiological expression of the gene for PrP-like protein, PrPLP/Dpl, by brain endothelial cells and its ectopic expression in neurons of PrP-deficient mice ataxic due to Purkinje cell degeneration
    Am. J. Pathol. 157(5), 1447-1452 (2000) IF:5.487
    A. Li, S. Sakaguchi (corresponding author), K. Shigematsu, R. Atarashi, BC. Roy, R. Nakaoke, K. Arima, N. Okimura, J. Kopacek and S. Katamine
  37. Early appearance but lagged accumulation of detergent-insoluble prion protein in the brains of mice inoculated with a mouse-adapted Creutzfeldt-Jakob disease agent
    Cell. Mol. Neurobiol. 20(6), 717-730 (2000) IF:2.483
    R. Nakaoke, S. Sakaguchi, R. Atarashi, N. Nishida, K. Arima, K. Shigematsu and S. Katamine
  38. Identification of a novel gene encoding a PrP-like protein expressed as chimeric transcripts fused to PrP exon 1/2 in ataxic mouse line with a disrupted PrP gene
    Cell. Mol. Neurobiol. 20(5), 553-567 (2000) IF:2.483
    A. Li, S. Sakaguchi (corresponding author), R. Atarashi, BC. Roy, R. Nakaoke, K. Arima, N. Okimura, J. Kopacek and Kazuto Shigematsu
  39. Upregulation of the genes encoding lysosomal hydrolases, a perforin-like protein, and peroxidases in the brains of mice affected with an experimental prion disease
    J. Virol. 74, 411-417 (2000) IF:5.332
    J. Kopacek, S. Sakaguchi, K. Shigematsu, N. Nishida, R. Atarashi, R. Nakaoke, R. Moriuchi, M. Niwa and S. Katamine
  40. A mouse prion protein (PrP) transgene rescues Purkinje cell degeneration and demyelination in mice deficient for PrP
    Lab. Invest. 79, 689-697 (1999) IF:4.479
    N. Nishida, P. Tremblay, T. Sugimoto, K. Shigematsu, S. Shirabe, C. Petromilli, SP. Erpel, R. Nakaoke, R. Atarashi, T. Houtani, M. Torchia, S. Sakaguchi, SJ. DeArmond, SB. Prusiner and S. Katamine
  41. Impaired motor coordination in mice lacking prion protein
    Cell. Mol. Neurobiol. 18, 731-742 (1998) IF:2.483
    S. Katamine, N. Nishida, T. Sugimoto, T. Noda, S. Sakaguchi, K. Shigematsu, Y. Kataoka, A. Nakatani, S. Hasegawa, R. Moriuchi and T. Miyamoto