論文 - 長谷川　喜弘

Suppression of heregulin β signaling by the single N-glycan deletion mutant of soluble ErbB3 protein.

Takahashi M, Hasegawa Y, Ikeda Y, Wada Y, Tajiri M, Ariki S, Takamiya R, Nishitani C, Araki M, Yamaguchi Y, Taniguchi N, Kuroki Y

The Journal of biological chemistry ( 46 )  288 ( 46 ) 32910 - 32921  2013年11月  [査読有り]

　概要を見る

Heregulin signaling is involved in various tumor proliferations and invasions thus, receptors of heregulin are targets for the cancer therapy. In this study we examined the suppressing effects of extracellular domains of ErbB2, ErbB3, and ErbB4 (soluble ErbB (sErbB)) on heregulin β signaling in human breast cancer cell line MCF7. It was found that sErbB3 suppresses ligand-induced activation ofErbBreceptors,PI3K/AktandRas/Erk pathwaysmosteffectively sErbB2 scarcely suppresses ligand-induced signaling, and sErbB4 suppresses receptor activation at ∼10% efficiency of sErbB3. It was revealed that sErbB3 does not decrease the effective ligands but decreases the effective receptors. By using small interfering RNA (siRNA) for ErbB receptors, we determined that sErbB3 suppresses the heregulin β signaling by interfering ErbB3-containing heterodimers including ErbB2/ErbB3. By introducing the mutation of N418Q to sErbB3, the signaling-inhibitory effects were increased by 2-3-fold. Moreover, the sErbB3 N418Q mutant enhanced anticancer effects of lapatinib more effectively than the wild type. We also determined the structures of N-glycan on Asn-418. Results suggested that the N-glycan-deleted mutant of sErbB3 suppresses heregulin signaling via ErbB3-containing heterodimers more effectively than the wild type. Thus, we demonstrated that the sErbB3N418Qmutant is a potent inhibitor for heregulin β signaling. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.

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SURFACTANT PROTEINS A AND D SUPPRESS EPIDERMAL GROWTH FACTOR SIGNALING THROUGH INTERACTIONS WITH N-GLYCANS OF RECEPTOR

Yoshihiro Hasegawa, Motoko Takahashi, Shigeru Ariki, Daiki Asakawa, Michiko Tajiri, Yoshinao Wada, Rina Takamiya, Yasuaki Uehara, Jiro Hashimoto, Hiroki Takahashi, Yoshio Kuroki

RESPIROLOGY ( WILEY-BLACKWELL )  18   55 - 55  2013年11月  [査読有り]

Detection of N-glycolyated gangliosides in non-small-cell lung cancer using GMR8 monoclonal antibody

Nobuyoshi Hayashi, Hirofumi Chiba, Koji Kuronuma, Shinji Go, Yoshihiro Hasegawa, Motoko Takahashi, Shinsei Gasa, Atsushi Watanabe, Tadashi Hasegawa, Yoshio Kuroki, Jinichi Inokuchi, Hiroki Takahashi

CANCER SCIENCE ( WILEY-BLACKWELL )  104 ( 1 ) 43 - 47  2013年01月  [査読有り]

　概要を見る

Gangliosides are glycosphingolipids found on the cell surface. They act as recognition molecules or signal modulators and regulate cell proliferation and differentiation. N-glycolylneuraminic acid (NeuGc)-containing gangliosides have been detected in some neoplasms in humans, although they are usually absent in normal human tissues. Our aim was to evaluate the presence of NeuGc-containing gangliosides including GM3 (NeuGc) and assess their relationship with the prognosis of non-small-cell lung cancer (NSCLC). NeuGc-containing ganglioside expression in NSCLC tissues was analyzed immunohistochemically using the mouse monoclonal antibody GMR8, which is specific for gangliosides with NeuGc alpha 2,3Gal-terminal structures. On the basis of NeuGc-containing ganglioside expression, we performed survival analysis. We also investigated the differences in the effects of GM3 (N-acetylneuraminic acid [NeuAc]) and GM3 (NeuGc) on inhibition of epidermal growth factor receptor (EGFR) tyrosine kinase in A431 cells. As a result, the presence of NeuGc-containing gangliosides was evident in 86 of 93 (93.5%) NSCLC samples. The NSCLC patients with high NeuGc-containing ganglioside expression had a low overall survival rate and a significantly low progression-free survival rate. In the in vitro study, the inhibitory effect of GM3 on EGFR tyrosine kinase in A431 cells after exposure to GM3 (NeuGc) was lower than that after exposure to GM3 (NeuAc). In conclusion, NeuGc-containing gangliosides including GM3 (NeuGc) are widely expressed in NSCLC, and NeuGc-containing ganglioside expression is associated with patient survival. The difference in the effects of GM3 (NeuGc) and GM3 (NeuAc) on the inhibition of EGFR tyrosine kinase might contribute to improvement in the prognosis of NSCLC patients. (Cancer Sci 2013; 104: 4347)

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Surfactant Protein D Inhibits Adherence of Uropathogenic Escherichia coli to the Bladder Epithelial Cells and the Bacterium-induced Cytotoxicity A POSSIBLE FUNCTION IN URINARY TRACT

Yuichiro Kurimura, Chiaki Nishitani, Shigeru Ariki, Atsushi Saito, Yoshihiro Hasegawa, Motoko Takahashi, Jiro Hashimoto, Satoshi Takahashi, Taiji Tsukamoto, Yoshio Kuroki

JOURNAL OF BIOLOGICAL CHEMISTRY ( AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC )  287 ( 47 ) 39578 - 39588  2012年11月  [査読有り]

　概要を見る

The adherence of uropathogenic Escherichia coli (UPEC) to the host urothelial surface is the first step for establishing UPEC infection. Uroplakin Ia (UPIa), a glycoprotein expressed on bladder urothelium, serves as a receptor for FimH, a lectin located at bacterial pili, and their interaction initiates UPEC infection. Surfactant protein D (SP-D) is known to be expressed on mucosal surfaces in various tissues besides the lung. However, the functions of SP-D in the non-pulmonary tissues are poorly understood. The purposes of this study were to investigate the possible function of SP-D expressed in the bladder urothelium and the mechanisms by which SP-D functions. SP-D was expressed in human bladder mucosa, and its mRNA was increased in the bladder of the UPEC infection model in mice. SP-D directly bound to UPEC and strongly agglutinated them in a Ca2+-dependent manner. Co-incubation of SP-D with UPEC decreased the bacterial adherence to 5637 cells, the human bladder cell line, and the UPEC-induced cytotoxicity. In addition, preincubation of SP-D with 5637 cells resulted in the decreased adherence of UPEC to the cells and in a reduced number of cells injured by UPEC. SP-D directly bound to UPIa and competed with FimH for UPIa binding. Consistent with the in vitro data, the exogenous administration of SP-D inhibited UPEC adherence to the bladder and dampened UPEC-induced inflammation in mice. These results support the conclusion that SP-D can protect the bladder urothelium against UPEC infection and suggest a possible function of SP-D in urinary tract.

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Pulmonary surfactant protein A protects lung epithelium from cytotoxicity of human β-defensin 3.

Saito A, Ariki S, Sohma H, Nishitani C, Inoue K, Ebata N, Takahashi M, Hasegawa Y, Kuronuma K, Takahashi H, Kuroki Y

The Journal of biological chemistry ( 18 )  287 ( 18 ) 15034 - 15043  2012年04月  [査読有り]

　概要を見る

Defensins are important molecules in the innate immune system that eliminate infectious microbes. They also exhibit cytotoxicity against host cells in higher concentrations. The mechanisms by which hosts protect their own cells from cytotoxicity of defensins have been poorly understood. We found that the cytotoxicity of human beta-defensin 3 (hBD3) against lung epithelial cells was dose-dependently attenuated by pulmonary surfactant protein A (SP-A), a collectin implicated in host defense and regulation of inflammatory responses in the lung. The direct interaction between SP-A and hBD3 may be an important factor in decreasing this cytotoxicity because preincubation of epithelial cells with SP-A did not affect the cytotoxicity. Consistent with in vitro analysis, intratracheal administration of hBD3 to SP-A(-/-) mice resulted in more severe tissue damage compared with that in WT mice. These data indicate that SP-A protects lung epithelium from tissue injury caused by hBD3. Furthermore, we found that the functional region of SP-A lies within Tyr(161)-Lys(201). Synthetic peptide corresponding to this region, tentatively called SP-A Y161-G200, also inhibited cytotoxicity of hBD3 in a dose-dependent manner. The SP-A Y161-G200 is a candidate as a therapeutic reagent that prevents tissue injury during inflammation.

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