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| 1.
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論文
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Pham, Hoa Q. ; Yoshioka, Kazuaki ; Mohri, Hiromi ; Nakata, Hiroki ; Aki, Sho ; Ishimaru, Kazuhiro ; Takuwa, Noriko ; Takuwa, Yoh ; 吉岡, 和晃 ; 仲田, 浩規 ; 安藝, 翔 ; 多久和, 典子 ; 多久和, 陽
概要:
金沢大学医薬保健研究域医学系<br />Phosphatidylinositol 3-phosphate (PI(3)P) is the predominant phosphoinositide species in early endos
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omes and autophagosomes, in which PI(3)P dictates traffic of these organelles. Phosphoinositide levels are tightly regulated by lipid-kinases and -phosphatases; however, a phosphatase that converts PI(3)P back to phosphatidylinositol in the endosomal and autophagosomal compartments is not fully understood. We investigated the subcellular distribution and functions of myotubularin-related protein-4 (MTMR4), which is distinct among other MTMRs in that it possesses a PI(3)P-binding FYVE domain, in lung alveolar epithelium-derived A549 cells. MTMR4 was localized mainly in late endosomes and autophagosomes. MTMR4 knockdown markedly suppressed the motility, fusion, and fission of PI(3)P-enriched structures, resulting in decreases in late endosomes, autophagosomes, and lysosomes, and enlargement of PI(3)P-enriched early and late endosomes. In amino acid- and serum-starved cells, MTMR4 knockdown decreased both autophagosomes and autolysosomes and markedly increased PI(3)P-containing autophagosomes and late endosomes, suggesting that the fusion with lysosomes of autophagosomes and late endosomes might be impaired. Notably, MTMR4 knockdown inhibited the nuclear translocation of starvation stress responsive transcription factor-EB (TFEB) with reduced expression of lysosome-related genes in starved cells. These findings indicate that MTMR4 is essential for the integrity of endocytic and autophagic pathways. © 2018 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.<br />Embargo Period 12 months
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| 2.
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Yamagishi, Ryoko ; Wakayama, Tomohiko ; Nakata, Hiroki ; Adthapanyawanich, Kannika ; Kumchantuek, Tewarat ; Yamamoto, Miyuki ; Iseki, Shoichi
概要:
In the major salivary glands of mice, acinar cells in the parotid gland (PG) are known to be the main site for the produ
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ction of the digestive enzyme α-amylase, whereas α-amylase production in the submandibular gland (SMG) and sublingual gland (SLG), as well as the cell types responsible for α-amylase production, has been less firmly established. To clarify this issue, we examined the expression and localization of both the mRNA and protein of α-amylase in the major salivary glands of male and female mice by quantitative and histochemical methods. α-amylase mRNA levels were higher in the order of PG, SMG, and SLG. No sexual difference was observed in α-amylase mRNA levels in the PG and SLG, whereas α-amylase mRNA levels in the female SMG were approximately 30% those in the male SMG. Using in situ hybridization and immunohistochemistry, signals for α-amylase mRNA and protein were found to be strongly positive in acinar cells of the PG, serous demilune cells of the SLG, and granular convoluted tubule (GCT) cells of the male SMG, weakly positive in seromucous acinar cells of the male and female SMG, and negative in mucous acinar cells of the SLG. These results clarified that α-amylase is produced mainly by GCT cells and partly by acinar cells in the SMG, whereas it is produced exclusively by serous demilune cells in the SLG of mice.
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| 3.
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Nakata, Hiroki ; Wakayama, Tomohiko ; Takai, Yoshimi ; Iseki, Shoichi
概要:
The aim of this study was to establish a quantitative standard for the cellular composition in seminiferous tubules at e
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ach stage of spermatogenesis in the mouse testis, and thereby evaluate abnormalities in the infertile mouse testis. We applied a combination of lectin histochemistry for acrosomes and immunohistochemistry for various specific cell markers, both of which were visualized with fluorescence, on paraffin sections of the testis. We first examined seminiferous tubules from normal mice and counted the number of each cell type at each stage of spermatogenesis. We then examined seminiferous tubules from genetically modified mice deficient (-/-) for one of the cell adhesion molecules, nectin-2 or nectin-3, and compared the number of each cell type at each stage of spermatogenesis with the corresponding value in normal mice. In both nectin-2-/- and nectin-3-/- mice, which are infertile despite the apparently normal morphology of the seminiferous epithelia, we measured a progressive loss in the later-step spermatids, with significantly lower numbers of step 11–16 spermatids in nectin-3-/- mice and step 15–16 spermatids in nectin-2-/- mice as compared with that in normal control mice. The present study demonstrated that a quantitative analysis of cellular compositions at different stages in seminiferous tubules was useful for evaluating abnormalities in spermatogenesis.
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| 4.
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論文
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Hirata, Miki ; Tajima, Hidehiro ; Miyashita, Tomoharu ; Miyata, Takashi ; Nakanuma, Shinichi ; Makino, Isamu ; Hayashi, Hironori ; Oyama, Katsunobu ; Takamura, Hiroyuki ; Ninomiya, Itasu ; Fushida, Sachio ; Nakata, Hiroki ; Iseki, Shoichi ; Harada, Shinichi ; Wakayama, Tomohiko ; Ohta, Tetsuo
概要:
Oxaliplatin-based chemotherapy plays an important role in the treatment of colorectal liver metastases. Oxaliplatin, however, causes sinusoidal obstruction syndrome (SOS), which is characterized by portal hypertension, splenomegaly,
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thrombocytopenia, and liver dysfunction. SOS is diagnosed histopathologically by disruption of the sinusoidal endothelium, collagen deposition, fbrosis especially around zone 3, dilatation of the sinusoidal space and congestion. This study assessed the characteristics of a rat model of SOS. SOS was induced in rats by administration of monocrotaline (MCT). Blood chemistries and macroscopic and microscopic fndings were compared in rats administered MCT and vehicle (control group). Levels of expression in the liver of CD41, P-selectin, rat endothelial cell antigen-1, CD34, and cleaved caspase-3 were analyzed immunohistochemically. Moreover, livers of these rats were analyzed by electron microscopy. Macroscopically, MCT-treated rats showed accumulation of bloody ascites and blue liver and were diagnosed with SOS histologically. Serum concentrations of aspartate aminotransferase (P=0.003), alanine aminotransferase (P=0.008), total-bilirubin (P=0.012), direct-bilirubin (P=0.007), indirect-bilirubin (P=0.003), lactate dehydrogenase (P<0.001) and hyaluronic acid (P=0.016) were signifcantly higher, and platelet counts signifcantly lower (P=0.004), in MCT-treated than in control rats. The livers of MCT-treated rats were immunohistochemically positive for CD41 and P-selectin, suggesting platelet aggregates; for rat endothelial cell antigen-1 and CD34, suggesting sinusoidal endothelial disorder; and for cleaved caspase-3, suggesting hepatocyte apoptosis. Electron microscopic fndings revealed platelet aggregation in the space of Disse in the MCT group. Extravasated platelet aggregation in Disse's space may be involved in the development of SOS.
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| 5.
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論文
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仲田, 浩規 ; Nakata, Hiroki
概要:
蛍光染色またはPAS染色を用いた半自動の三次元再構築方法を考案し、0日齢、21日齢、70日齢の精細管の三次元再構築を各3例行い、生後発達におけるマウス精細管の本数・分岐・長さ・走行・相互関係を明らかにした。また、精子形成が開始した場所と精子
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形成の波を三次元で明らかにし、精子形成に関わる空間的な偏りを明らかにした。<br />We developed a technique to analyze the high-resolution three-dimensional (3D) structure of seminiferous tubules. It consists of the segmentation of tubules in serial paraffin sections of the testis by marking the basement membrane with periodic acid-Schiff or a fluorescent anti-laminin antibody followed by the 3D reconstruction of tubules with high-performance software. Using this method, we analyzed testes from mice at different ages and accurately elucidated the 3D structure of seminiferous tubules, including the number and length of tubules as well as the numbers of connections with the rete testis, branching points, and blind ends. We also analyzed the distribution and direction of spermatogenic waves along the length of adult seminiferous tubules as well as the site of the first onset of spermatogenesis in postnatal seminiferous tubules.<br />研究課題/領域番号:16K18976, 研究期間(年度):2016-04-01 - 2019-03-31
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| 6.
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仲田, 浩規 ; Nakata, Hiroki
概要:
細胞接着分子を介した造精細胞とセルトリ細胞の相互作用は精子形成に重要な役割を持つ。特に、造精細胞に発現する細胞接着分子 Cadm1は精子形成に必須である。最近我々は、Cadm1と結合するアダプター蛋白質としてMpp6を見いだした。ウエスタン
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ブロット法および免疫組織化学により精巣におけるMpp6の発現と局在を明らかにした。また、免疫沈降によりCadm1とMpp6の相互作用を確認し、さらにMpp6と相互作用する新規分子を複数同定した。<br />The interaction of germ cells and sertoli cells through cell adhesion molecules is important in spermatogenesis. Cell adhesion molecule-1 (Cadm1), which is expressed in germ cells, is essential for spermatogenesis. Recently we found out Mpp6 as an adopter protein which binds Cadm1. Using Western blot analysis and immunohistochemistry, we revealed the expression and localization of Mpp6 in the mouse testis. Moreover, we confirmed the interaction of Cadm1 and Mpp6 by immunoprecipitation and also identified several new molecules which interact with Mpp6.<br />研究課題/領域番号:24890074, 研究期間(年度):2012-08-31 - 2014-03-31
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