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Articles by N Terada
Total Records ( 6 ) for N Terada
  S Ohno , N Terada , N Ohno , S Saitoh , Y Saitoh and Y. Fujii
 

Our final goal of morphological and immunohistochemical studies is that all findings examined in animal experiments should reflect the physiologically functional background. Therefore, the preservation of original components in cells and tissues of animals is necessary for describing the functional morphology of living animal organs. It is generally accepted that morphological findings of various organs were easily modified by stopping their blood supply. There had been a need to develop a new preparation technique for freezing the living animal organs in vivo and then obtaining acceptable morphology and also immunolocalization of original components in functioning cells and tissues. We already developed the ‘in vivo cryotechnique’ (IVCT) not only for their morphology, but also for immunohistochemistry of many soluble components in various living animal organs. All physiological processes of cells and tissues were immediately immobilized by IVCT, and every component in the cells and tissues was maintained in situ at the time of freezing. Thus, the ischaemic or anoxic effects on them could be minimized by IVCT. Our specially designed cryoknife with liquid cryogen has solved the morphological and immunohistochemical problems which are inevitable with the conventional preparation methods at a light or electron microscopic level. The IVCT will be extremely useful for arresting transient physiological processes and for maintaining any intracellular components in situ, such as rapidly changing signal molecules, membrane channels and receptors.

  Y Saitoh , N Terada , S Saitoh , N Ohno , Y Fujii and S. Ohno
 

Soluble proteins and glycogen particles are well preserved in paraffin-embedded sections prepared by in vivo cryotechnique (IVCT) and cryobiopsy followed by freeze substitution fixation. We performed confocal laser scanning microscopic analyses on the distributions of glycogen with periodic acid-Schiff (PAS) staining and serum proteins with immunostaining for mouse liver tissues. Livers of fully fed mice showed a strong fluorescence signal of PAS staining in all hepatocytes and immunofluorescence of immunoglobulin kappa light chain (Ig) in blood vessels and bile canaliculi. However, some hepatocytes in mechanically damaged livers were PAS-negative and Ig-immunopositive, showing extraction of glycogen particles and infiltration of serum proteins in hepatocytes. By three-dimensional (3D) reconstruction of serial optical sections, interconnecting hepatic sinusoids and bile canaliculi were detected with Ig immunostaining between trabecular hepatocytes that were PAS stained. In PAS-stained samples under fasting conditions, interstitial structures along sinusoids were clarified in vivo by 3D reconstruction because of the lower PAS staining intensity of hepatocytes. In addition, 100-µm-thick eosin-stained slices provided 3D structural images more than 30 µm in thickness away from tissue surfaces, showing blood vessels with flowing erythrocytes and networks of bile ducts and canaliculi. IVCT and cryobiopsy with histochemical analyses enabled us to visualize native hepatocytic glycogen and 3D structures, such as vascular networks, reflecting their living states by confocal laser scanning microscopy.

  N Terada , N Ohno , S Saitoh , Y Saitoh and S. Ohno
 

The purpose of this study was to clarify a previously controversial issue concerning glutamate (Glu) immunoreactivity (IR) in the inner segment (IS) of photoreceptors by using in vivo cryotechnique (IVCT) followed by freeze substitution (FS), which enabled us to analyze the cells and tissues reflecting living states. Eyeballs from anesthetized mice were directly frozen using IVCT. The frozen tissues were processed for FS fixation in acetone containing chemical fixatives, and embedded in paraffin. Deparaffinized sections were immunostained with an anti-Glu antibody. The strongest Glu-IR was obtained in the specimens prepared by FS with paraformaldehyde or a low concentration of glutaraldehyde, whereas no Glu-IR was obtained without the chemical fixatives. The Glu was immunolocalized in the IS, outer and inner plexiform and ganglion cell layers. Thus, the immunolocalization of Glu in the IS was clearly demonstrated using IVCT. (J Histochem Cytochem 57:883–888, 2009)

  T Kobayashi , T Inoue , Y Shimizu , N Terada , A Maeno , Y Kajita , T Yamasaki , T Kamba , Y Toda , Y Mikami , T Yamada , T Kamoto , O Ogawa and E. Nakamura
 

We and others previously showed that signaling through cSrc or atypical protein kinase C (aPKC) pathway regulates the proliferation of prostate cancer cells and is associated with their progression to castrate-resistance in vivo. However, the interrelation of these two kinases has been largely unexplored. In the present study, we show that androgen-induced activation of cSrc regulates the activity of aPKC through the small molecular weight G protein Rac1 in androgen-dependent LNCaP cells. Knockdown of cSrc in those cells reduces the phosphorylation of aPKC and the abundance of activated form of Rac1. Additionally, the treatment of those cells with Rac1 inhibitor repressed cell cycle progression at G1/S transition. In fact, forced expression of a constitutively active Rac1 mutant in LNCaP cells promoted cell proliferation under androgen-depleted conditions both in vitro and in vivo. Moreover, LNCaP C4-2 and AILNCaP cells, the syngeneic androgen-independent sublines from LNCaP cells, harbored abundant Rac1-GTP. Importantly, the inhibition of Rac1 suppressed cell proliferation and induced apoptotic cell death in all prostate cancer cell lines tested irrespective of their androgen-dependence. In immunohistochemical evaluation of tumor specimens from prostate cancer patients, Rac1 pathway appeared to be activated in the majority of castrate-resistant diseases. Collectively, our present results both in vitro and in vivo highly implicate that Rac1 can be a potential therapeutic target for patients with advanced prostate cancer, especially those with castrate-resistant status.

  Y Ge , A. L Wu , C Warnes , J Liu , C Zhang , H Kawasome , N Terada , M. D Boppart , C. J Schoenherr and J. Chen
 

Rapamycin-sensitive signaling is required for skeletal muscle differentiation and remodeling. In cultured myoblasts, the mammalian target of rapamycin (mTOR) has been reported to regulate differentiation at different stages through distinct mechanisms, including one that is independent of mTOR kinase activity. However, the kinase-independent function of mTOR remains controversial, and no in vivo studies have examined those mTOR myogenic mechanisms previously identified in vitro. In this study, we find that rapamycin impairs injury-induced muscle regeneration. To validate the role of mTOR with genetic evidence and to probe the mechanism of mTOR function, we have generated and characterized transgenic mice expressing two mutants of mTOR under the control of human skeletal actin (HSA) promoter: rapamycin-resistant (RR) and RR/kinase-inactive (RR/KI). Our results show that muscle regeneration in rapamycin-administered mice is restored by RR-mTOR expression. In the RR/KI-mTOR mice, nascent myofiber formation during the early phase of regeneration proceeds in the presence of rapamycin, but growth of the regenerating myofibers is blocked by rapamycin. Igf2 mRNA levels increase drastically during early regeneration, which is sensitive to rapamycin in wild-type muscles but partially resistant to rapamycin in both RR- and RR/KI-mTOR muscles, consistent with mTOR regulation of Igf2 expression in a kinase-independent manner. Furthermore, systemic ablation of S6K1, a target of mTOR kinase, results in impaired muscle growth but normal nascent myofiber formation during regeneration. Therefore, mTOR regulates muscle regeneration through kinase-independent and kinase-dependent mechanisms at the stages of nascent myofiber formation and myofiber growth, respectively.

 
 
 
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