Researchers Database

azuma morio

    DivisionofMolecularPharmacology Assistant Professor
Last Updated :2021/11/23

Researcher Information

URL

J-Global ID

Research Interests

  • メラニン凝集ホルモン   細胞外マトリックス   ゼブラフィッシュ   チョウザメ   ポリプテルス   魚類   ペプチドホルモン   視床下部ー下垂体軸   下垂体前葉   下垂体後葉   軸索誘導   

Research Areas

  • Life sciences / Anatomy
  • Life sciences / Pharmacology
  • Life sciences / Morphology, anatomy

Academic & Professional Experience

  • 2018/06 - Today  Jichi Medical UniversitySchool of Medicine講師
  • 2013/04 - 2018/05  Jichi Medical UniversitySchool of Medicine助教
  • 2010/04 - 2013/03  University of Toyama日本学術振興会特別研究員DC1

Education

  • 2010/04 - 2013/03  University of Toyama  Graduate School of Science and Engineering for Education
  • 2008/04 - 2010/03  University of Toyama  Graduate School of Science and Engineering for Education
  • 2004/04 - 2008/03  University of Toyama  Faculty of Science  Department of Biology

Association Memberships

  • THE JAPANESE ASSOCIATION OF ANATOMISTS   THE JAPANESE PHARMACOLOGICAL SOCIETY   THE JAPAN SOCIETY FOR PITUITARY RESEARCH   THE ZOOLOGICAL SOCIETY OF JAPAN   JAPAN SOCIETY FOR COMPARATIVE ENDOCRINOLOGY   

Published Papers

  • Takeshi Inagaki, Ken Fujiwara, Yoshiaki Shinohara, Morio Azuma, Reiji Yamazaki, Kiyomi Mashima, Atsushi Sakamoto, Takashi Yashiro, Nobuhiko Ohno
    Histochemistry and cell biology 155 (4) 503 - 512 2021/04 
    Hypertension leads to structural remodeling of cerebral blood vessels, which has been implicated in the pathophysiology of cerebrovascular diseases. The remodeling and progression of arteriolosclerosis under hypertension involve fibrosis along with the production of type I collagen around cerebral arterioles. However, the source and regulatory mechanisms of this collagen production remain elusive. In this study, we examined if perivascular macrophages (PVMs) are involved in collagen production around cerebral small vessels in hypertensive SHRSP/Izm rats. Immunoreactivity for type I collagen around cerebral small vessels in 12-week-old hypertensive rats tended to higher than those in 4-week-old hypertensive and 12-week-old control rats. In ultrastructural analyses using transmission electron microscopy, the substantial deposition of collagen fibers could be observed in the intercellular spaces around PVMs near the arterioles of rats with prolonged hypertension. In situ hybridization analyses revealed that cells positive for mRNA of Col1a1, which comprises type I collagen, were observed near cerebral small vessels. The Col1a1-positive cells around cerebral small vessels were colocalized with immunoreactivity for CD206, a marker for PVMs, but not with those for glial fibrillary acidic protein or desmin, markers for other perivascular cells such as astrocytes and vascular smooth muscle cells. These results demonstrated that enhanced production of type I collagen is observed around cerebral small vessels in rats with prolonged hypertension and Col1a1 is expressed by PVMs, and support the concept that PVMs are involved in collagen production and vascular fibrosis under hypertensive conditions.
  • 内陸県におけるアマゾン産淡水エイによる刺傷の1例
    田中 保平, 山黒 友丘, 伊澤 祥光, 米川 力, 東 森生, 輿水 崇鏡, 間藤 卓
    日本救急医学会雑誌 (一社)日本救急医学会 31 (8) 317 - 320 0915-924X 2020/08 
    症例は患者が飼育中のアマゾン産淡水エイPotamotrygon leopoldiの水替え中に手背を刺されて来院したもので,刺傷後から疼痛が激しく,創部の洗浄と消毒に加え,海産エイ毒の解毒方法に準じて40℃の湯に創部を浸漬したところ,疼痛の軽減を図ることができた。その後,疼痛が数日の間は継続したが,広範な壊死を来すことはなく細菌感染などの併発もなく治癒した。エイ毒は複数の蛋白毒で構成され,疼痛・腫脹・壊死を来すほか,ショック症状・呼吸困難を来し,ときに死に至ることもある。一部の海産タンパク毒と同様に高温に弱く,患部を温水に浸漬することで症状を軽減できるといわれるが,種差・性差・成熟度による毒性・毒量を含めて不明な点が多い。本邦では淡水エイによる刺傷の報告が少なく,今回の症例のように後遺症を認めずに治癒する症例がある一方で,後遺症や手術を要した症例も報告されている。淡水エイの毒性については不確定なことが多く,症例および治療経験の蓄積が重要であると考えられた。(著者抄録)
  • Kiyomi Mashima, Morio Azuma, Ken Fujiwara, Takashi Inagaki, Iekuni Oh, Takashi Ikeda, Kento Umino, Hirofumi Nakano, Kaoru Morita, Kazuya Sato, Daisuke Minakata, Ryoko Yamasaki, Masahiro Ashizawa, Chihiro Yamamoto, Shin-Ichiro Fujiwara, Kaoru Hatano, Ken Ohmine, Kazuo Muroi, Nobuhiko Ohno, Yoshinobu Kanda
    Acta histochemica et cytochemica 53 (3) 43 - 53 2020/06 [Refereed][Not invited]
     
    Leukemias are refractory hematopoietic malignancies, for which the development of new therapeutic agents requires in vivo studies using tumor-bearing mouse models. Although several organs are commonly examined in such studies to evaluate the disease course, the effectiveness of interventions and the localization of tumor cells in the affected organs are still unclear. In this study, we histologically examined the distribution of leukemia cells in several organs using two leukemic mouse models produced by the administration of two cell lines (THP-1, a human myelomonocytic leukemia, and A20, a mouse B cell leukemia/lymphoma) to severe immunodeficient mice. Survival of the mice depended on the tumor burden. Although A20 and THP-1 tumor cells massively infiltrated the parenchyma of the liver and spleen at 21 days after transplantation, A20 cells were hardly found in connective tissues in Glisson's capsule in the liver as compared with THP-1 cells. In the bone marrow, there was more severe infiltration of A20 cells than THP-1 cells. THP-1 and A20 cells were widely spread in the lungs, but were rarely observed in the small intestine. These findings suggest that each leukemia model has a unique localization of tumor cells in several affected organs, which could critically affect the disease course and the efficacy of therapeutic agents, including cellular immunotherapies.
  • Morio Azuma, Takehiro Tsukada, Takeshi Inagaki, Fujianti Casmad, Depicha Jindatip, Alimuddin Tofrizal, Rita Maliza, Khongorzul Batchuluun, Rahimi Syaidah, Nobuhiko Ohno, Ken Fujiwara, Motoshi Kikuchi, Takashi Yashiro
    Acta histochemica et cytochemica 51 (5) 145 - 152 0044-5991 2018/10 [Refereed][Not invited]
     
    Laminin, a major basement membrane protein, comprises three subunit chains: α, β, and γ chains. Among these chains, only the laminin α chain is capable of signaling via laminin receptors. Although laminin isoforms containing the α5 chain were reported to be the first laminin produced during rat anterior pituitary gland development, the functions of these isoforms are unknown. We used immunohistochemical techniques to localize the laminin α5 chain and its specific receptor, basal cell adhesion molecule (BCAM), in fetal and adult pituitary gland. Laminin α5 chain immunoreactivity was observed in the basement membrane of the primordial adenohypophysis at embryonic days 12.5 to 19.5. Double immunostaining showed that BCAM was present and co-localized with the laminin α5 chain in the tissue. Quantitative analysis showed that the laminin α5 chain and BCAM were expressed in the anterior pituitary gland during postnatal development and in adulthood (postnatal day 60). In the adult gland, co-localization of the laminin α5 chain and BCAM was observed, and BCAM was detected in both the folliculo-stellate cells and endothelial cells. These results suggest that laminin α5 chain signaling via BCAM occurs in both the fetal adenohypophysis and adult anterior pituitary gland.
  • Nguyen HB, Thai TQ, Sui Y, Azuma M, Fujiwara K, Ohno N
    Frontiers in neural circuits 12 108  2018 [Refereed][Not invited]
  • Alimuddin Tofrizal, Ken Fujiwara, Morio Azuma, Motoshi Kikuchi, Depicha Jindatip, Takashi Yashiro, Shozo Yamada
    MEDICAL MOLECULAR MORPHOLOGY 50 (3) 145 - 154 1860-1480 2017/09 [Refereed][Not invited]
     
    Extracellular matrix (ECM) is essential in tissue physiology and pathologic conditions such as tumorigenesis. It affects tumor cell behavior, proliferation, and metastasis. Pituitary adenomas differ in their clinical characteristics, including ECM deposition, and we recently reported that the characteristics of collagen-producing cells differed between control human anterior pituitary gland and pituitary adenomas. ECM deposition is not defined solely by production; degradation and maintenance are also important. Tissue inhibitors of metalloproteinases (TIMPs) help maintain ECM by inhibiting degradation caused by matrix metalloproteases. The present study attempted to characterize TIMP-expressing cells in the human anterior pituitary. Specimens of human pituitary adenomas and control pituitary were obtained during surgery, and in situ hybridization for TIMP1, TIMP2, TIMP3, and TIMP4, followed by immunohistochemistry, was used to characterize TIMP-expressing cells. TIMP expression exhibited a distinct pattern in the human anterior pituitary. Azan staining showed that fibrous matrix deposition varied among pituitary adenomas and that the area of fibrosis was associated with the number and number of types of TIMP3-expressing cells. These results suggest that TIMPs are important in the maintenance of ECM in human pituitary and that TIMP expressions are altered in fibrosis associated with pituitary adenoma.
  • Rita Maliza, Ken Fujiwara, Morio Azuma, Motoshi Kikuchi, Takashi Yashiro
    ENDOCRINE JOURNAL 64 (6) 633 - 638 0918-8959 2017/06 [Refereed][Not invited]
     
    Retinoic acid (RA) is converted from retinal by retinaldehyde dehydrogenases (RALDHs) and is an essential signaling molecule in embryonic and adult tissue. We previously reported that RALDH1 was produced in the rat anterior pituitary gland and hypothesized that RA was generated in the gland. Midkine (MK) is an RA-inducible growth factor, and MK production in the rat anterior pituitary gland was recently reported. However, the mechanism that regulates gene expression of MK in the pituitary gland has not been determined. To investigate regulation of MK production in the anterior pituitary gland, we analyzed changes in MK mRNA in cultured rat anterior pituitary cells. We identified MK expressing cells by double-staining with in situ hybridization and immunohistochemical techniques for RALDH1. MK mRNA was expressed in RALDH1-producing cells in the anterior pituitary gland. Using isolated anterior pituitary cells of rats, we examined the effect of RA on gene expression of MK. Quantitative real-time PCR revealed that 72 h exposure to a concentration of 10(-6) M of retinal and all-trans retinoic acid increased MK mRNA levels by about 2-fold. Moreover, the stimulatory effect of all-trans retinoic acid was mimicked by the RA receptor agonist Am80. This is the first report to show that RA is important in regulating MK expression in rat anterior pituitary gland.
  • Khongorzul Batchuluun, Morio Azuma, Takashi Yashiro, Motoshi Kikuchi
    CELL AND TISSUE RESEARCH 368 (1) 125 - 133 0302-766X 2017/04 [Refereed][Not invited]
     
    The rat anterior pituitary is composed of hormone-producing cells, non-hormone-producing cells (referred to as folliculostellate cells) and marginal layer cells. In the adult rat, progenitor cells of hormone-producing cells have recently been reported to be maintained within this non-hormone-producing cell population. In tissue, non-hormone-producing cells construct homophilic cell aggregates by the differential expression of the cell adhesion molecule E-cadherin. We have previously shown that Notch signaling, a known regulator of progenitor cells in a number of organs, is activated in the cell aggregates. We now investigate the relationship between Notch signaling and E-cadherin-mediated cell adhesion in the pituitary gland. Immunohistochemically, Notch signaling receptor Notch2 and the ligand Jagged1 were localized within E-cadherin-positive cells in the marginal cell layer and in the main part of the anterior lobe, whereas Notch1 was localized in E-cadherin-positive and -negative cells. Activation of Notch signaling within E-cadherin-positive cells was confirmed by immunostaining of the Notch target HES1. Notch2 and Jagged1 were always co-localized within the same cells suggesting that homologous cells have reciprocal effects in activating Notch signaling. When the E-cadherin function was inhibited by exposure to a monoclonal antibody (DECMA-1) in primary monolayer cell culture, the percentage of HES1-positive cells among Notch2-positive cells was less than half that of the control. The present results suggest that E-cadherin-mediated cell attachment is necessary for the activation of Notch signaling in the anterior pituitary gland but not for the expression of the Notch2 molecule.
  • Khongorzul Batchuluun, Morio Azuma, Ken Fujiwara, Takashi Yashiro, Motoshi Kikuchi
    ACTA HISTOCHEMICA ET CYTOCHEMICA 50 (2) 63 - 69 0044-5991 2017 [Refereed][Not invited]
     
    After publication of reports describing the presence of stem/progenitor cells among non-hormone-producing cells in the pituitary, the mechanism responsible for proliferation and differentiation generated considerable interest. Several studies have suggested that Notch signaling is involved. In the present study, we examined the histochemical relationship between Notch signaling molecules and the transcription factor SOX2 in rat pituitary. Combined in situ hybridization and immunohistochemistry showed that Notch2 mRNA and SOX2 were co-expressed at embryonic day 14.5 in most cells in the adenohypophyseal primordium. In adult rat pituitary, double immunohistochemistry showed that SOX2 and either Notch2 or the Notch signaling target HES1 were co-localized within cells with large oval nuclei in both the marginal cell layer and cell aggregates in the main part of the anterior lobe, which are believed to be stem cell niches. Furthermore, when the Notch signaling inhibitor DAPT was added to a primary culture of adult rat anterior pituitary cells, the proportion of SOX2-expressing cells within Notch2-positive cells was approximately 30% lower. These findings suggest that Notch signaling has a role in maintaining the stemness of precursor cells in the adult rat pituitary gland.
  • Rahimi Syaidah, Takehiro Tsukada, Morio Azuma, Kotaro Horiguchi, Ken Fujiwara, Motoshi Kikuchi, Takashi Yashiro
    Acta histochemica et cytochemica 49 (6) 171 - 179 0044-5991 2016/12 [Refereed][Not invited]
     
    Fibromodulin belongs to the family of small leucine-rich proteoglycans (SLRPs), an active component of extracellular matrix. It directly binds collagens to promote fibrillogenesis and also binds transforming growth factor-beta (TGFβ) to antagonize its actions. Our previous studies of rat anterior pituitary gland revealed that fibromodulin is expressed in folliculostellate cells and pericytes. Although our recent study showed that TGFβ2 secreted from folliculostellate cells induces collagen synthesis in pericytes, the involvement of fibromodulin in TGFβ2-mediated collagen regulation has not been studied. The present study examined the effect of TGFβ2 on fibromodulin synthesis in rat anterior pituitary gland. In situ hybridization for TGFβ receptor II and immunohistological techniques revealed the presence of TGFβ receptor II in folliculostellate cells and pericytes. To confirm canonical TGFβ intracellular signaling, Smad2 immunocytochemistry was performed. Nuclear translocation of Smad2 was observed in folliculostellate cells and pericytes after TGFβ2 treatment. TGFβ2 strongly enhanced fibromodulin mRNA and protein expressions, and TGFβ2-induced mRNA expression was completely blocked by TGFβ receptor I inhibitor (SB431542). These results suggest that folliculostellate cells and pericytes exhibit canonical TGFβ2 signaling, which is associated with fibromodulin production. Thus, this is the first report to show that TGFβ signaling regulates the endogenous TGFβ antagonist fibromodulin in the gland.
  • Rita Maliza, Ken Fujiwara, Takehiro Tsukada, Morio Azuma, Motoshi Kikuchi, Takashi Yashiro
    Endocrine journal 63 (6) 555 - 61 0918-8959 2016/06 [Refereed][Not invited]
     
    Retinoic acid (RA) is an important signaling molecule in embryonic development and adult tissue. The actions of RA are mediated by the nuclear receptors retinoic acid receptor (RAR) and retinoid X receptor (RXR), which regulate gene expression. RAR and RXR are widely expressed in the anterior pituitary gland. RA was reported to stimulate growth hormone (GH) gene expression in the anterior pituitary cells. However, current evidence is unclear on the role of RA in gene expression of growth hormone-releasing hormone receptor (Ghrh-r), growth hormone secretagogue receptor (Ghs-r) and somatostatin receptors (Sst-rs). Using isolated anterior pituitary cells of rats, we examined the effects of RA on gene expression of these receptors and GH release. Quantitative real-time PCR revealed that treatment with all-trans retinoic acid (ATRA; 10(-6) M) for 24 h increased gene expression levels of Ghrh-r and Ghs-r; however, expressions of Sst-r2 and Sst-r5 were unchanged. Combination treatment with the RAR-agonist Am80 and RXR-agonist PA024 mimicked the effects of ATRA on Ghrh-r and Ghs-r gene expressions. Exposure of isolated pituitary cells to ATRA had no effect on basal GH release. In contrast, ATRA increased growth hormone-releasing hormone (GHRH)- and ghrelin-stimulated GH release from cultured anterior pituitary cells. Our results suggest that expressions of Ghrh-r and Ghs-r are regulated by RA through the RAR-RXR receptor complex and that RA enhances the effects of GHRH and ghrelin on GH release from the anterior pituitary gland.
  • Takehiro Tsukada, Morio Azuma, Kotaro Horiguchi, Ken Fujiwara, Tom Kouki, Motoshi Kikuchi, Takashi Yashiro
    The Journal of endocrinology 229 (2) 159 - 70 0022-0795 2016/05 [Refereed][Not invited]
     
    The anterior pituitary gland comprises five types of endocrine cells plus non-endocrine cells including folliculostellate cells, endothelial cells, and capillary mural cells (pericytes). In addition to being controlled by the hypothalamic-pituitary-target organ axis, the functions of these cells are likely regulated by local cell and extracellular matrix (ECM) interactions. However, these complex interactions are not fully understood. We investigated folliculostellate cell-mediated cell-to-cell interaction. Using S100β-GFP transgenic rats, which express GFP in folliculostellate cells, we designed a three-dimensional cell culture to examine the effects of folliculostellate cells. Interestingly, removal of folliculostellate cells reduced collagen synthesis (Col1a1 and Col3a1). Because pericytes are important collagen-producing cells in the gland, we stained for desmin (a pericyte marker). Removal of folliculostellate cells resulted in fewer desmin-positive pericytes and less desmin mRNA. We then attempted to identify the factor mediating folliculostellate cell-pericyte interaction. RT-PCR and in situ hybridization revealed that the important profibrotic factor transforming growth factor beta-2 (TGFβ2) was specifically expressed in folliculostellate cells and that TGFβ receptor II was expressed in pericytes, endothelial cells, and parenchymal cells. Immunocytochemistry showed that TGFβ2 induced SMAD2 nuclear translocation in pericytes. TGFβ2 increased collagen synthesis in a dose-dependent manner. This action was completely blocked by TGFβ receptor I inhibitor (SB431542). Diminished collagen synthesis in folliculostellate cell-deficient cell aggregates was partially recovered by TGFβ2. TGFβ2-mediated folliculostellate cell-pericyte interaction appears to be essential for collagen synthesis in rat anterior pituitary. This finding sheds new light on local cell-ECM interactions in the gland.
  • Yuta Ichijo, Yuta Mochimaru, Morio Azuma, Kazuhiro Satou, Jun Negishi, Takashi Nakakura, Natsuki Oshima, Chihiro Mogi, Koichi Sato, Kouhei Matsuda, Fumikazu Okajima, Hideaki Tomura
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 469 (1) 81 - 86 0006-291X 2016/01 [Refereed][Not invited]
     
    Human G2A is activated by various stimuli such as lysophosphatidylcholine (LPC), 9-hydroxyoctadecadienoic acid (9-HODE), and protons. The receptor is coupled to multiple intracellular signaling pathways, including the G(s)-proteinicAMP/CRE, G(12/13)-protein/Rho/SRE, and G(q)-protein/phospholipase C/NFAT pathways. In the present study, we examined whether zebrafish G2A homologs (zG2A-a and zG2A-b) could respond to these stimuli and activate multiple intracellular signaling pathways. We also examined whether histidine residue and basic amino acid residue in the N-terminus of the homologs also play roles similar to those played by human G2A residues if the homologs sense protons. We found that the zG2A-a showed the high CRE, SRE, and NFAT activities, however, zG2A-b showed only the high SRE activity under a pH of 8.0. Extracellular acidification from pH 7.4 to 6.3 ameliorated these activities in zG2A-a-expressing cells. On the other hand, acidification ameliorated the SRE activity but not the CRE and NFAT activities in zG2A-b-expressing cells. LPC or 9-HODE did not modify any activity of either homolog. The substitution of histidine residue at the 174th position from the N-terminus of zG2A-a to asparagine residue attenuated proton-induced CRE and NFAT activities but not SRE activity. The substitution of arginine residue at the 32nd position from the N-terminus of zG2A-a to the alanine residue also attenuated its high and the proton-induced CRE and NFAT activities. On the contrary, the substitution did not attenuate SRE activity. The substitution of the arginine residue at the 10th position from the N-terminus of zG2A-b to the alanine residue also did not attenuate its high or the proton induced SRE activity. These results indicate that zebrafish G2A homologs were activated by protons but not by LPC and 9-HODE, and the activation mechanisms of the homologs were similar to those of human G2A. (C) 2015 Elsevier Inc. All rights reserved.
  • Morio Azuma, Alimuddin Tofrizal, Rita Maliza, Khongorzul Batchuluun, Dini Ramadhani, Rahimi Syaidah, Takehiro Tsukada, Ken Fujiwara, Motoshi Kikuchi, Kotaro Horiguchi, Takashi Yashiro
    Acta histochemica et cytochemica 48 (6) 185 - 92 0044-5991 2015/12 [Refereed][Not invited]
     
    The extracellular matrix (ECM) is important in creating cellular environments in tissues. Recent studies have demonstrated that ECM components are localized in anterior pituitary cells and affect cell activity. Thus, clarifying the mechanism responsible for ECM maintenance would improve understanding of gland function. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of matrix metalloproteinases and participate in ECM degradation. In this study, we investigated whether cells expressing TIMPs are present in rat anterior pituitary gland. Reverse transcription polymerase chain reaction was used to analyze expression of the TIMP family (TIMP1-4), and cells producing TIMPs in the gland were identified by using in situ hybridization. Expression of TIMP1, TIMP2, and TIMP3 mRNAs was detected, and the TIMP-expressing cells were located in the gland. The TIMP-expressing cells were also investigated by means of double-staining with in situ hybridization and immunohistochemical techniques. Double-staining revealed that TIMP1 mRNA was expressed in folliculostellate cells. TIMP2 mRNA was detected in folliculostellate cells, prolactin cells, and thyroid-stimulating hormone cells. TIMP3 mRNA was identified in endothelial cells, pericytes, novel desmin-immunopositive perivascular cells, and folliculostellate cells. These findings indicate that TIMP1-, TIMP2-, and TIMP3-expressing cells are present in rat anterior pituitary gland and that they are involved in maintaining ECM components.
  • Ken Fujiwara, Kotaro Horiguchi, Rita Maliza, Alimuddin Tofrizal, Khongorzul Batchuluun, Dini Ramadhani, Rahimi Syaidah, Takehiro Tsukada, Morio Azuma, Motoshi Kikuchi, Takashi Yashiro
    Cell and tissue research 359 (3) 909 - 14 0302-766X 2015/03 [Refereed][Not invited]
     
    Midkine (MK) belongs to a family of secreted heparin-binding growth factors and is highly expressed in various tissues during development. MK has multiple functions, such as regulation of cell proliferation, migration, survival and differentiation. We recently reported that MK mRNA is strongly expressed in the developing rat pituitary gland. In the adult pituitary, however, expression of MK and its receptor and the characteristics of the cells that produce them, have not been determined. Therefore, in this study, we investigate whether MK and its receptor, protein tyrosine phosphatase receptor-type Z (Ptprz1), are present in the adult rat pituitary. In situ hybridization, real-time reverse transcription-PCR and immunoblotting were performed to assess MK and Ptprz1 expression. We also characterize MK- and Ptprz1-expressing cells by double-staining with in situ hybridization and immunohistochemical techniques for each pituitary hormone or S100 protein [a marker of folliculostellate (FS) cells]. MK-expressing cells were located in the anterior and posterior lobes but not in the intermediate lobe. Double-staining and immunoblotting revealed that MK mRNA and protein were only expressed in FS cells in the anterior pituitary. Regarding Ptprz1 expression, Ptprz1 mRNA was detected in adrenocorticotropic hormone (ACTH) cells and growth hormone (GH) cells but not in prolactin cells, thyroid-stimulating hormone cells, luteinizing hormone cells, or FS cells. These findings suggest that MK produced in FS cells acts locally on ACTH cells and GH cells via Ptprz1 in the adult rat anterior pituitary.
  • Yuta Mochimaru, Morio Azuma, Natsuki Oshima, Yuta Ichijo, Kazuhiro Satou, Kouhei Matsuda, Yoichi Asaoka, Hiroshi Nishina, Takashi Nakakura, Chihiro Mogi, Koichi Sato, Fumikazu Okajima, Hideaki Tomura
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 457 (4) 493 - 499 0006-291X 2015/02 [Refereed][Not invited]
     
    Mammalian ovarian G-protein-coupled receptor 1 (OGR1) and GPR4 are identified as a proton-sensing G-protein-coupled receptor coupling to multiple intracellular signaling pathways. In the present study, we examined whether zebra fish OGR1 and GPR4 homologs (zOGR1 and zGPR4) could sense protons and activate the multiple intracellular signaling pathways and, if so, whether the similar positions of histidine residue, which is critical for sensing protons in mammalian OCR and GPR4, also play a role to sense protons and activate the multiple signaling pathways in the zebra fish receptors. We found that extracellular acidic pH stimulated CRE-, SRE-, and NEAT-promoter activities in zOGR1 overexpressed cells and stimulated CRE- and SRE- but not NFAT-promoter activities in zGPR4 overexpressed cells. The substitution of histidine residues at the 12th, 15th, 162th, and 264th positions from the N-terminal of zOGR1 with phenylalanine attenuated the proton-induced SRE-promoter activities. The mutation of the histidine residue at the 78th but not the 84th position from the N-terminal of zGPR4 to phenylalanine attenuated the proton-induced SRE-promoter activities. These results suggest that zOGR1 and zGPR4 are also proton-sensing G-protein-coupled receptors, and the receptor activation mechanisms may be similar to those of the mammalian receptors. (C) 2015 Elsevier Inc. All rights reserved.
  • Ken Fujiwara, Rita Maliza, Alimuddin Tofrizal, Khongorzul Batchuluun, Dini Ramadhani, Takehiro Tsukada, Morio Azuma, Kotaro Horiguchi, Motoshi Kikuchi, Takashi Yashiro
    Cell and tissue research 357 (1) 337 - 44 0302-766X 2014/07 [Refereed][Not invited]
     
    Pituitary gland development is controlled by numerous signaling molecules, which are produced in the oral ectoderm and diencephalon. A newly described family of heparin-binding growth factors, namely midkine (MK)/pleiotrophin (PTN), is involved in regulating the growth and differentiation of many tissues and organs. Using in situ hybridization with digoxigenin-labeled cRNA probes, we detected cells expressing MK and PTN in the developing rat pituitary gland. At embryonic day 12.5 (E12.5), MK expression was localized in Rathke's pouch (derived from the oral ectoderm) and in the neurohypophyseal bud (derived from the diencephalon). From E12.5 to E19.5, MK mRNA was expressed in the developing neurohypophysis, and expression gradually decreased in the developing adenohypophysis. To characterize MK-expressing cells, we performed double-staining of MK mRNA and anterior pituitary hormones. At E19.5, no MK-expressing cells were stained with any hormone. In contrast, PTN was expressed only in the neurohypophysis primordium during all embryonic stages. In situ hybridization clearly showed that MK was expressed in primitive (immature/undifferentiated) adenohypophyseal cells and neurohypophyseal cells, whereas PTN was expressed only in neurohypophyseal cells. Thus, MK and PTN might play roles as signaling molecules during pituitary development.
  • Dini Ramadhani, Takehiro Tsukada, Ken Fujiwara, Morio Azuma, Motoshi Kikuchi, Takashi Yashiro
    Acta histochemica et cytochemica 47 (5) 231 - 7 0044-5991 2014 [Refereed][Not invited]
     
    Cell-matrix interaction is required for tissue development. Laminin, a major constituent of the basement membrane, is important for structural support and as a ligand in tissue development. Laminin has 19 isoforms, which are determined by combinational assembly of five α, three β, and three γ chains (eg, laminin 121 is α1, β2, and γ1). However, no report has identified the laminin isoforms expressed during pituitary development. We used in situ hybridization to investigate all laminin chains expressed during rat anterior pituitary development. The α5 chain was expressed during early pituitary development (embryonic day 12.5-15.5). Expression of α1 and α4 chains was noted in vasculature cells at embryonic day 19.5, but later diminished. The α1 chain was re-expressed in parenchymal cells of anterior lobe from postnatal day 10 (P10), while the α4 chain was present in vasculature cells from P30. The α2 and α3 chains were transiently expressed in vasculature cells and anterior lobe, respectively, only at P30. Widespread distribution of β and γ chains was also observed during development. These findings suggest that numerous laminin isoforms are involved in anterior pituitary gland development and that alteration of the expression pattern is required for proper development of the gland.
  • Takehiro Tsukada, Ken Fujiwara, Kotaro Horiguchi, Morio Azuma, Dini Ramadhani, Alimuddin Tofrizal, Khongorzul Batchuluun, Rita Maliza, Rahimi Syaidah, Motoshi Kikuchi, Takashi Yashiro
    Acta histochemica et cytochemica 47 (5) 239 - 45 0044-5991 2014 [Refereed][Not invited]
     
    The anterior pituitary gland is organized tissue comprising hormone-producing cells and folliculostellate (FS) cells. FS cells interconnect to form a meshwork, and their cytoplasmic processes are anchored by a basement membrane containing laminin. Recently, we developed a three-dimensional (3D) cell culture that reproduces this FS cell architecture. In this study of the novel function of FS cells, we used transgenic rats that express green fluorescent protein in FS cells for the 3D culture. Anterior pituitary cells were cultured with different proportions of FS cells (0%, 5%, 10%, and 20%). Anterior pituitary cells containing 5-20% FS cells formed round/oval cell aggregates, whereas amorphous cell aggregates were formed in the absence of FS cells. Interestingly, immunohistochemistry showed laminin-immunopositive cells instead of extracellular laminin deposition in FS cell-deficient cell aggregates. Double-immunostaining revealed that these laminin-immunopositive cells were gonadotrophs. Laminin mRNA expression did not differ in relation to the presence or absence of FS cells. When anterior pituitary cells with no FS cells were cultured with FS cell-conditioned medium, the proportion of laminin-immunopositive cells was lower than in control. These results suggest that a humoral factor from FS cells is required for laminin release from gonadotrophs.
  • Shunsuke Shimizu, Morio Azuma, Noriaki Morimoto, Sakae Kikuyama, Kouhei Matsuda
    PEPTIDES 46 102 - 107 0196-9781 2013/08 [Refereed][Not invited]
     
    Neuropeptide Y (NPY) is a potent orexigenic neuropeptide implicated in appetite regulation in mammals. However, except for teleost fish such as the goldfish and zebrafish, the involvement of NPY in the regulation of feeding in non-mammalian vertebrates has not been well studied. Anuran amphibian larvae feed and grow during the pre- and pro-metamorphic stages, but, thereafter they stop feeding as the metamorphic climax approaches. Therefore, orexigenic factors seem to play important roles in pre- and pro-metamorphic larvae. We investigated the role of NPY in food intake using bullfrog larvae including pre- and pro-metamorphic stages, and examined the effect of feeding status on the expression level of the NPY transcript in the hypothalamus. NPY mRNA levels in hypothalamus specimens obtained from larvae that had been fasted for 3 days were higher than those in larvae that had been fed normally. We then investigated the effect of intracerebroventricular (ICV) administration of NPY on food intake in the larvae. Cumulative food intake was significantly increased by ICV administration of NPY (5 and 10 pmol/g body weight, BW) during a 15-min observation period. The NPY-induced orexigenic action (10 pmol/g BW) was blocked by treatment with a NPY Y1 receptor antagonist, BIBP-3226 (100 pmol/g BW). These results indicate that NPY acts as an orexigenic factor in bullfrog larvae. (C) 2013 Elsevier Inc. All rights reserved.
  • Morio Azuma, Tunehiro Suzuki, Hiroshi Mochida, Shigeyasu Tanaka, Kouhei Matsuda
    Peptides 43 40 - 47 0196-9781 2013/05 [Refereed][Not invited]
     
    Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that stimulates the release of adenohypophyseal hormone from the pituitary in fish. In the goldfish, PACAP induces the release of somatolactin (SL), in particular, from cultured pituitary cells. SL belongs to the growth hormone and prolactin family, and comprises two molecular variants termed SL-α and SL-β in goldfish. However, there is no information about the involvement of PACAP in the regulation of SL-α and SL-β release and the expression of their mRNAs. Therefore, we examined the effect of PACAP on SL-α and SL-β release from cultured goldfish pituitary cells. Treatment with PACAP (10-10-10-7 M) increased the release of both SL-α and SL-β. The stimulatory action of PACAP (10 -9 M) on SL-α and SL-β release was blocked by treatment with a PACAP-selective receptor (PAC1R) antagonist, PACAP (6-38) (10-6 M). We also examined whether PACAP affects the expression of SL-α and SL-β mRNAs in cultured pituitary cells. Treatment with PACAP (10-9 and 10-8 M) for 6 h decreased the expression level of SL-α mRNA but increased that of SL-β mRNA. The action of PACAP (10-8 M) on SL-β mRNA expression was blocked by treatment with PACAP(6-38) (10-6 M), whereas PACAP(6-38) elicited no change in the expression of SL-α mRNA. These results indicate that in cultured goldfish pituitary cells, PACAP stimulates the release of SL-α and SL-β, and expression of SL-β mRNA, via the PAC1R-signaling pathway. However, the mechanism whereby PACAP inhibits the expression of SL-α mRNA does not seem to be mediated by PAC1R signaling. © 2013 Elsevier Inc.
  • M. Azuma, K. Wada, J. Leprince, M-C. Tonon, M. Uchiyama, A. Takahashi, H. Vaudry, K. Matsuda
    JOURNAL OF NEUROENDOCRINOLOGY 25 (3) 312 - 321 0953-8194 2013/03 [Refereed][Not invited]
     
    The present study aimed to investigate the distribution of the octadecaneuropeptide (ODN) in the goldfish brain and to look for a possible effect of ODN on somatolactin (SL) release from pituitary cells. A discrete population of ODN-immunoreactive neurones was localised in the lateral part of the nucleus lateralis tuberis. These neurones sent projections through the neurohypophyseal tract towards the neurohypophysis, and nerve fibres were seen in the close vicinity of SL-producing cells in the pars intermedia. Incubation of cultured goldfish pituitary cells with graded concentrations of ODN (109105m) induced a dose-dependent stimulation of SL-, but not SL-, release. ODN-evoked SL release was blocked by the metabotrophic endozepine receptor antagonist cyclo18[DLeu5]OP but was not affected by the central-type benzodiazepine receptor antagonist flumazenil. ODN-induced SL release was suppressed by treatment with the phospholipase C (PLC) inhibitor U-73122 but not with the protein kinase A (PKA) inhibitor H-89. These results indicate that, in fish, ODN produced by hypothalamic neurones acts as a hypophysiotrophic neuropeptide stimulating SL release. The effect of ODN is mediated through a metabotrophic endozepine receptor positively coupled to the PLC/inositol 1,4,5-trisphosphate/protein kinase C-signalling pathway.
  • Kouhei Matsuda, Morio Azuma, Keisuke Maruyama, Seiji Shioda
    OBESITY RESEARCH & CLINICAL PRACTICE 7 (1) E1 - E7 1871-403X 2013/01 [Refereed][Not invited]
     
    Food intake is a fundamental for animals to surviving and keeping offspring. The hypothalamic region of the brain and the brain stem in vertebrates are a center that plays an important role in the control of feeding and its related behaviors including locomotor and psychomotor activities. Pituitary adenylate cyclase-activating polypeptide (PACAP) has firstly been identified as a hypophysiotropic hormone involved in adenohypophyseal hormone release, and subsequently has been considered as a neuropeptide exerting multifunctional roles in the central and peripheral nervous systems and several tissues in vertebrates. For example, PACAP is involved in the neuroendocrine control of food intake and acts as an anorexigenic peptide to regulate satiety. Recent works on animal models such as rodents and goldfish which are both excellent animal models for investigating the neuroendocrinological roles of PACAP have been extensively examined and considerable information has been accumulated. In addition, psychophysiological effects of PACAP on emotional behavior have recently been found. Therefore, this review article provides an overview of the neuroendocrine regulation of feeding behavior and psyphysiological activity by PACAP in vertebrates. (C) 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
  • Kouhei Matsuda, Atsushi Sakashita, Eri Yokobori, Morio Azuma
    NEUROPEPTIDES 46 (6) 275 - 283 0143-4179 2012/12 [Refereed][Not invited]
     
    Neuropeptide Y (NPY) is a neuropeptide distributed widely among vertebrates. In mammals, NPY and its related peptides such as pancreatic polypeptide and peptide YY (PYY) are distributed throughout the brain and gastrointestinal tissues, and are centrally involved in many physiological functions such as the regulation of food intake, locomotion and psychomotor activities through their receptors. With regard to non-mammalian vertebrates, there has also been intensive study aimed at the identification and functional characterization of NPY, PYY and their receptors, and recent investigations of the role of NPY have revealed that it exerts several behavioral effects in goldfish and zebrafish. Both of these species are excellent teleost fish models, in which it has been demonstrated that NPY increases food consumption as an orexigenic factor and reduces locomotor activity, as is the case in mammals. This paper reviews current knowledge of NPY derived from studies of teleost fish, as representative non-mammals, focusing particularly on the role of the NPY system, and examines its significance from a comparative viewpoint. (C) 2012 Elsevier Ltd. All rights reserved.
  • Morio Azuma, Tsunehiro Suzuki, Hiroshi Mochida, Shigeyasu Tanaka, Minoru Uchiyama, Akiyoshi Takahashi, Kouhei Matsuda
    CELL AND TISSUE RESEARCH 1 350 (1) 167 - 176 0302-766X 2012/10 [Refereed][Not invited]
     
    Somatolactin (SL) is a pituitary hormone belonging to the growth hormone/prolactin family of adenohypophyseal hormones. In teleost fish, SL is encoded by one or two paralogous genes, namely SL-alpha and -beta. Our previous studies have revealed that pituitary adenylate-cyclase-activating polypeptide stimulates SL release from cultured goldfish pituitary cells, whereas melanin-concentrating hormone suppresses this release. As in other fish, the goldfish possesses SL-alpha and -beta. So far, however, no useful means of detecting the respective SLs immunologically in this species has been possible. In order to achieve this aim, we raised rabbit antisera against synthetic peptide fragments deduced from the goldfish SL-alpha and -beta cDNA sequences. Using these antisera, we observed adenohypophyseal cells showing SL-alpha- and -beta-like immunoreactivities in the goldfish pituitary, especially the pars intermedia (PI). Several cells in the PI showed the colocalization of SL-alpha- and -beta-like immunoreactivities. Then, using single-cell polymerase chain reaction with laser microdissection, we examined SL-alpha and -beta gene expression in adenohypophyseal cells showing SL-alpha- or -beta-like immunoreactivity. Among cultured pituitary cells, we observed three types of cell: those that possess transcripts of SL-alpha, -beta, or both. These results suggest a polymorphism of SL-producing cells in the goldfish pituitary.
  • Kouhei Matsuda, Morio Azuma, Ki Sung Kang
    VITAMINS AND HORMONES: SLEEP HORMONES, VOL 89 89 341 - 361 0083-6729 2012 [Refereed][Not invited]
     
    Orexin is a neuropeptide distributed widely among vertebrates. In mammals, orexin and its receptor system are involved in the regulation of food intake, locomotion, and psychomotor activities including the sleep/wakefulness cycle. With regard to nonmammalian vertebrates, there has also been intensive study aimed at the identification and functional characterization of orexin and its receptor, and recent investigations of the role of orexin have revealed that it exerts behavioral effects in teleost fish. Goldfish and zebrafish are excellent teleost fish models, and in these species it has been demonstrated that orexin increases food consumption as an orexigenic factor and enhances locomotor activity, as well as being involved in the regulation of active and rest status (circadian rhythmicity and the sleep/wakefulness cycle), as is the case in mammals. This chapter reviews current knowledge of orexin derived from studies of teleost fish, as representative nonmammals, focusing particularly on the role of the orexin system, and examines its significance from a comparative viewpoint. (C) 2012 Elsevier Inc.
  • Ryo Nishiguchi, Morio Azuma, Eri Yokobori, Minoru Uchiyama, Kouhei Matsuda
    Frontiers in Endocrinology 3 122  1664-2392 2012 [Refereed][Not invited]
     
    Gonadotropin-releasing hormone (GnRH) is an evolutionarily conserved neuropeptide with 10 amino acid residues, of which several structural variants exist. A molecular form known as GnRH2 ([His5 Trp7 Tyr8]GnRH, also known as chicken GnRH II) is widely distributed in vertebrates except for rodents, and has recently been implicated in the regulation of feeding behavior in goldfish. However, the influence of GnRH2 on feeding behavior in other fish has not yet been studied. In the present study, therefore, we investigated the role of GnRH2 in the regulation of feeding behavior in a zebrafish model, and examined its involvement in food intake after intracerebroventricular (ICV) administration. ICV injection of GnRH2 at 0.1 and 1 pmol/g body weight (BW) induced a marked decrease of food consumption in a dose-dependent manner during 30 min after feeding. Cumulative food intake was significantly decreased by ICV injection of GnRH2 at 1 pmol/g BW during the 30-min post-treatment observation period. The anorexigenic action of GnRH2 was completely blocked by treatment with the GnRH type I receptor antagonist Antide at 25 pmol/g BW. We also examined the effect of feeding condition on the expression level of the GnRH2 transcript in the hypothalamus. Levels of GnRH2 mRNA obtained from fish that had been provided excess food for 7 days were higher than those in fish that had been fed normally. These results suggest that, in zebrafish, GnRH2 acts as an anorexigenic factor, as is the case in goldfish. © 2012 Nishiguchi, Azuma, Yokobori, Uchiyama and Matsuda.
  • Ki Sung Kang, Satowa Yahashi, Morio Azuma, Atsushi Sakashita, Seiji Shioda, Kouhei Matsuda
    JOURNAL OF MOLECULAR NEUROSCIENCE 45 (2) 172 - 176 0895-8696 2011/10 [Refereed][Not invited]
     
    Although spice compounds have several pharmacological and biochemical actions such as antioxidant activity, their physiological effects on neuropeptides related to feeding regulation are not well known. The aim of the present study was to identify the pharmacological activities of spice compounds on appetite regulation using a goldfish (Carassius auratus) model with emphasis on the role of neuropeptides. The spice compounds used in this study were curcumin, piperine, and ursolic acid. Goldfish were injected intraperitoneally with test solutions containing each spice or vehicle (including 10% dimethyl sulfoxide in saline), and the changes in food intake were measured every 15 min for 60 min. Among the tested spice compounds, curcumin was found to reduce cumulative food intake and was thus selected for further experiments. Pretreatment with capsaicin, a neurotoxin of afferent nerves, abolished the curcumin-induced decrease of food intake. Curcumin-induced anorexigenic action was also attenuated by intracerebroventricular injection of the corticotropin-releasing hormone (CRH) receptor antagonist alpha-helical CRH((9-41)). We also examined the expression levels of mRNA for CRH, which is a potent anorexigenic neuropeptide in goldfish, in the diencephalon at 1 h after treatment with curcumin, and found that they were increased. Therefore, the reduction of appetite induced by curcumin treatment in goldfish was suggested to be mediated by the vagal afferent and subsequently through the CRH/CRH receptor pathway.
  • Eri Yokobori, Kenji Kojima, Morio Azuma, Ki Sung Kang, Sho Maejima, Minoru Uchiyama, Kouhei Matsuda
    PEPTIDES 32 (7) 1357 - 1362 0196-9781 2011/07 [Refereed][Not invited]
     
    Orexin is a potent orexigenic neuropeptide implicated in feeding regulation of mammals. However, except for the case of goldfish, the involvement of orexin in the feeding behavior of teleost fish has not well been studied. Therefore, we investigated the role of orexin on food intake using a zebrafish (Danio redo) model. We examined the effect of feeding status on orexin-like immunoreactivity and the expression level of orexin transcript in the brain. The number of neuronal cells showing orexin-like immunoreactivity in the hypothalamic region, including the posterior tuberal nucleus, was significantly increased in fish fasted for 7 days. Orexin precursor mRNA levels in the brain obtained from fish fasted for 7 days were higher than those in fish that had been fed normally. We then investigated the effect of intracerebroventricular (ICV) administration of orexin A on food intake. Cumulative food intake was significantly increased by ICV administration of orexin A (at 0.3 and 3 pmol/g body weight, BW) during a 60-min observation period after treatment. The orexin A-induced orexigenic action (at 0.3 pmol/g BW) was blocked by treatment with an orexin receptor antagonist, SB334867, at 10 pmol/g BW. These results indicate that orexin A acts as feeding regulator in the zebrafish. (C) 2011 Elsevier Inc. All rights reserved.
  • Ki Sung Kang, Kanako Shimizu, Mono Azuma, Yuhta Ui, Kouta Nakamura, Minoru Uchiyama, Kouhei Matsuda
    PEPTIDES 1 32 (1) 31 - 35 0196-9781 2011/01 [Refereed][Not invited]
     
    Intracerebroventricular (ICV)administration of gonadotropin-releasing hormone II (GnRH II), which plays a crucial role in the regulation of reproduction in vertebrates, markedly reduces food intake in goldfish. However, the neurochemical pathways involved in the anorexigenic action of GnRH II and its interaction with other neuropeptides have not yet been identified. Alpha-melanocyte-stimulating hormone (alpha-MSH), corticotropin-releasing hormone (CRH) and CRH-related peptides play a major role in feeding control as potent anorexigenic neuropeptides in goldfish. However, our previous study has indicated that the GnRH II-induced anorexigenic action is not blocked by treatment with melanocortin 4 receptor (MC4R) and CRH receptor antagonists. Therefore, in the present study, we further examined whether the anorexigenic effects of alpha-MSH and CRH in goldfish could be mediated through the GnRH receptor neuronal pathway. ICV injection of the MC4R agonist, melanotan II (80 pmol/g body weight; BW), significantly reduced food intake, and its anorexigenic effect was suppressed by ICV pre-administration of the GnRH type I receptor antagonist, antide (100 pmol/g BW). The CRH-induced (50 pmol/g BW) anorexigenic action was also blocked by treatment with antide. ICV injection of CRH (50 pmol/g BW) induced a significant increase of the GnRH II mRNA level in the hypothalamus, while ICV injection of melanotan II (80 pmol/g BW) had no effect on the level of GnRH II mRNA. These results indicate that, in goldfish, the anorexigenic actions of alpha-MSH and CRH are mediated through the GnRH type I receptor-signaling pathway, and that the GnRH II system regulates feeding behavior. (C) 2010 Elsevier Inc. All rights reserved.
  • Ki Sung Kang, Satowa Yahashi, Morio Azuma, Kouhei Matsuda
    PEPTIDES 31 (11) 2130 - 2134 0196-9781 2010/11 [Refereed][Not invited]
     
    We have been extensively investigating the mechanisms by which neuropeptides regulate feeding behavior by using a goldfish (Carassius auratus) model In this species the anorexigenic action of melanocortin peptide is centrally mediated via the corticotropin-releasing hormone (CRH)/CRH receptor neuronal system whereas sulfated cholecystokinin octapeptide (CCK-8s) is Involved in the appetite regulation as a peripheral anorexigenic factor The aim of the present study was to identify the mechanism of the anorexigenic effect of peripherally injected CCK-8s which has not yet been identified in goldfish Co-administration of capsaicin a neurotoxin that destroys primary sensory afferents at 100 nmol/g BW blocked the anorexigenic action of intraperitoneally injected CCK-8s (100 pmol/g BW) whereas the anorexigenic action of intracerebroventricularly injected CCK-8s (5 pmol/g BW) was not blocked by co-administration of capsaicin Pre-treatment with a specific CRH receptor antagonist alpha-helical CRH((9-41)) attenuated the anorexigenic action of CCK-8s The expression level of CRH mRNA in the diencephalic tissue of the CCK-8s-injected group was not changed but the level of proopiomelanocortin mRNA was significantly Increased at 1 h after treatment Therefore we have identified for the first time that the reduction of appetite induced by peripherally injected CCK-8s in goldfish appears to be mediated by the vagal afferent and subsequently through the melanocortin- and corticotropin-releasing hormone-signaling pathways (C) 2010 Elsevier Inc All rights reserved
  • Mio Tanaka, Morio Azuma, Yumika Nejigaki, Yumiko Saito, Kanta Mizusawa, Minoru Uchiyama, Akiyoshi Takahashi, Seiji Shioda, Kouhei Matsuda
    JOURNAL OF ENDOCRINOLOGY 203 (3) 389 - 398 0022-0795 2009/12 [Refereed][Not invited]
     
    Melanin-concentrating hormone (MCH)-containing neurons directly innervate the adenohypophysis in the teleost pituitary. We examined immunohistochemically the relationship between MCH-containing nerve fibres or endings and somatolactin (SL)-producing cells in the goldfish pituitary. Nerve fibres or endings with MCH-like immunoreactivity were identified in the neurohypophysis in close proximity to the adenohypophysial cells showing SL-like immunoreactivity. We also examined the effect of MCH on SL release from Cultured goldfish pituitary cells and SL synthesis using a cell immunoblot and a real-time PCR method. Treatment of individually dispersed pituitary cells with MCH 10(-7) M for 3 h decreased the area of SL-like immunoreactivity on immunoblots, and MCH-induced reductions in SL release were blocked by treatment with the mammalian MCH receptor (MCHR) antagonist, compound-30, at a concentration of 10(-5) M. Treatment with 10(-7) M MCH for 3 h did not affect sl-alpha and -beta (smtla and -b as given in the Zfin Database) mRNA expression levels. These led us to explore the signal transduction mechanism leading to the inhibition of SL release, for which we examined whether MCH-induced reductions in SL release are mediated by the G(i) or G(q) protein-coupled signalling pathway. The MCH-induced reductions in SL release were abolished by treatment with the G(i/o) protein inhibitors, NF023 (10(-5) M) or pertussis toxin (260 ng/ml), but not by the phospholipase C inhibitor, U-73122 (3 x 10(-6) M). These results indicate that MCH can potentially function as a hypothalamic factor suppressing SL release via the MCHR, and subsequently through the G(i) protein to inhibit the adenylate cyclase/cAMP/protein kinase A-signalling pathway in goldfish pituitary cells. journal of Endocrinology (2009) 203, 389-398
  • Morio Azuma, Mio Tanaka, Yumika Nejigaki, Minoru Uchiyama, Akiyoshi Takahashi, Seiji Shioda, Kouhei Matsuda
    PEPTIDES 30 (7) 1260 - 1266 0196-9781 2009/07 [Refereed][Not invited]
     
    In the goldfish pituitary, nerve fibers containing pituitary adenylate cyclase-activating polypeptide (PACAP) are located in close proximity to somatolactin (SL)-producing cells, and PACAP enhances SL release from cultured pituitary cells. However, there is little information about the mechanism of PACAP-induced SL release. In order to elucidate this issue, we used the cell immunoblot method. Treatment with PACAP at 10(-8) and 10(-7) M, but not with vasoactive intestinal polypeptide (VIP) at the same concentrations, increased the immunoblot area for SL-like immunoreactivity from dispersed pituitary cells, and PACAP-induced SL release was blocked by treatment with the PACAP selective receptor (PAC(1)R) antagonist, PACAP((6-38)), at 10(-6) M, but not with the PACAP/VIP receptor antagonist, VIP((6-28)). PACAP-induced SL release was also attenuated by treatment with the calmodulin inhibitor, calmidazolium at 10(-6) M. This led us to explore the signal transduction mechanism up to SL release, and we examined whether PACAP-induced SL release is mediated by the adenylate cyclase (AC)/cAMP/protein kinase A (PKA)- or the phospholipase C (PLC)/inositol 1,4,5-trisphosphate (IP(3))/protein kinase C (PKC)-signaling pathway. PACAP-induced SL release was attenuated by treatment with the AC inhibitor, MDL-12330A, at 10(-5) M or with the PKA inhibitor, H-89, at 10(-5) M. PACAP-induced SL release was suppressed by treatment with the PLC inhibitor, U-73122, at 3 x 10(-6) M or with the PKC inhibitor, GF109203X, at 10(-6) M. These results suggest that PACAP can potentially function as a hypophysiotropic factor mediating SL release via the PAC(1)R and subsequently through perhaps the AC/cAMP/PKA- and the PLC/IP(3)/PKC-signaling pathways in goldfish pituitary cells. (C) 2009 Elsevier Inc. All rights reserved.

Conference Activities & Talks

MISC

Awards & Honors

  • 2017/10 第21回日本臨床内分泌学会学術総会最優秀賞受賞
     
    受賞者: 東 森生
  • 2008/08 第23回日本下垂体研究会優秀発表賞受賞
     
    受賞者: 東 森生

Research Grants & Projects

  • 条鰭類の進化モデルを用いた下垂体神経葉への軸索誘導因子の同定
    日本学術振興会:科学研究費助成事業 若手研究
    Date (from‐to) : 2020/04 -2023/03 
    Author : 東 森生
  • Can we prevent analgesic tolerance to morphine? Study of high-order opioid receptor signal complex and its clinical application.
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2017/04 -2020/03 
    Author : 輿水 崇鏡, 土屋 裕義, 東 森生
     
    本研究では、オピオイド麻薬が示す優れた鎮痛効果が、継続投与により耐性が生じ効き目が減弱する現象の解明を目指す。この鎮痛耐性を防ぎ、オピオイド麻薬の副作用の危険を軽減することは現時点では不可能である。臨床的には、効き目の減弱に伴い、投与薬物量の増加によって効果の維持を目指したり、別の鎮痛薬を用いるなどの方法で工夫されている。しかし、過量の鎮痛薬投与は有害作用の危険を高めるため、安全で安定した薬物療法が理想的である。本研究では、なぜ鎮痛耐性が生じ、一旦生じた耐性を効果的に治療するための手段はないのか、この2点の難題に挑戦している。本研究の特長として、最近、申請者らは、これまで鎮痛とは関連が知られていないホルモン受容体の欠損動物において、野生型と比較して1)痛みを感じにくく、2)鎮痛麻薬には感受性が高い性質を見出した。本研究では、この受容体欠損動物の知見を鎮痛治療に応用し、痛み閾値と鎮痛持続をコントロールする全く新しい鎮痛療法を世界で初めて提示することを試みている。 2018年度は、これまでの研究成果を論文として発表することができた。すなわち、我々は、福岡大学薬学部の研究チームとともに、強力な痛み止め効果を持つ医療用麻薬のモルヒネについて、鎮痛効果がより強く、長く続くことを可能にする方法を発見した。具体的には、脳内で放出されるバゾプレッシンホルモンの受け皿の1つとして働くV1b 受容体の働きを止めた実験動物を作成し解析した結果、医療用麻薬であるモルヒネの効果が強くなることを発見した。さらに、V1b 受容体の働きを薬で止めることによっても、医療用麻薬の効果が強くなることも見出した。この成果により、医療用麻薬とV1b 受容体の働きを抑制する薬を同時に用いることにより、医療用麻薬の効き目を増加させて、長く保つ治療が可能になると判明した。
  • 下垂体前葉内で産生される生理活性物質はプロラクチン産生腫瘍の形成に関与するか?
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2017/04 -2020/03 
    Author : 藤原 研, 屋代 隆, 東 森生
     
    プロラクチノーマの形成に関与する下垂体前葉内で産生される生理活性物質を探索するため、①腫瘍形成の過程における下垂体前葉内の生理活性物質および受容体の発現量の定量解析、②生理活性物質および受容体の形態学的同定を行った。前年度に、プロラクチノーマモデルラットを用い、プロラクチノーマ形成過程で発現変動する遺伝子をDNAマイクロアレイにより解析した。その結果、プロラクチノーマで著しく増加もしくは減少する遺伝子が明らかとなった。本年度は、その中から、幾つかの生理活性物質および受容体遺伝子を選び、リアルタイムPCR法で発現量解析を行った。さらに、遺伝子のクローニングを行い、RNAプローブを作製し、in situ hybridization法を用いて発現細胞の同定に成功した。そのうち、生理活性物質とその受容体ともにプロラクチノーマで発現が増加する因子を同定できた。さらに、組織解析からこれらの遺伝子はプロラクチン細胞に発現することが分かった。また、ラットプロラクチノーマから樹立した細胞株でこれらの発現を解析したところ、プロラクチンを発現しない細胞株では受容体は発現しているが、リガンドは発現していなかった。一方、プロラクチンを発現する細胞株では受容体とリガンドの両方を発現していることを見つけた。これらの結果から、この生理活性物質はプロラクチンで発現しオートクラインで作用することが示唆された。下垂体前葉内で産生される生理活性物質およびそれを受容する受容体がプロラクチノーマの形成に関与する可能性が考えられた。
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2016/04 -2018/03 
    Author : Azuma Morio
     
    The basement membrane is an extracellular scaffold for cells and aids in structural support of and barriers between tissues. It is known that the basement membrane components affect cell activity via their receptors. In the anterior pituitary gland, hormone-secreting cells are surrounded by various extracellular matrix including the basement membrane. The purpose of this study is to clarify the mechanism of gonadotropin secretion via laminin, a major basement membrane protein, in the gland. Immunohistochemistry showed that types of laminin α chain in rat anterior pituitary gland. Endocrine cells including gonadotrophs responded to laminins which exist in the gland. In addition, histological technic revealed localization of laminin receptors in the gland. Laminin may contribute to the regulation of hormone-secreting cells in the gland.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2013/04 -2016/03 
    Author : Kikuchi Motoshi, AZUMA Morio, YASHIRO Takashi
     
    The anterior pituitary is composed of types of hormone-producing cells. Progenitor cells that can differentiate into the types of cells were reported to be maintained in adult tissue. Differentiation is regulated by humoral factors, however, the mechanism to maintain progenitor cells was not understood. We previously showed Notch signaling, a regulator of progenitor cells in many organs, is activated in particular cell aggregates in rat pituitary. In this study, immunohistochemistry revealed a close relationship between Notch signaling molecules and cell adhesion molecule E-cadherin. Expression of the target HES1 decreased by E-cadherin inhibition in primary culture. Notch receptor and ligand were always co-localized within cells, suggesting homologous cells have reciprocal effects. We are further analyzing genes regulated by Notch signaling. The present study suggests that E-cadherin-mediated cell attachment is responsible for maintenance of progenitor cells through Notch signaling.
  • 下垂体前葉組織の機能発現における細胞間接着と細胞外マトリックスの役割
    自治医科大学:自治医科大学医学部研究奨励金
    Date (from‐to) : 2014 
    Author : 東 森生
  • 魚類下垂体ホルモンのソマトラクチンの分泌と合成に及ぼす視床下部ホルモンの影響
    Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
    Date (from‐to) : 2010 -2012 
    Author : 東 森生
     
    平成24年度では、「魚類下垂体ホルモンのソマトラクチン(SL)の分泌と合成に及ぼす視床下部ホルモンの影響」という研究課題のもと、平成23年度に作製したキンギョSL-αとSL-βを特異的に認識する抗血清を用いて、キンギョ下垂体初代培養細胞より分泌されるSL-αおよびSL-βの測定方法を検討し、SL-αおよびSL-βの分泌に及ぼす下垂体アデニル酸シクラーゼ活性化ポリペプチド(PACAP)の影響を調べた。キンギョ下垂体初代培養細胞より培養液中に分泌された各ホルモンを、ウエスタンブロット法により検出する方法を確立し、PACAPの添加により、SL-αとSL-β両方の分泌が促されることを見出した。さらに、PACAPによる各SL分泌促進作用は、PACAP特異的受容体であるPAC_1受容体を介して発揮されることを、受容体アンタゴニストを用いて明らかにした。 平成23年度の研究により、キンギョ下垂体におけるSL-αおよびSL-βmRNA発現量は、背地色に応答して変動することを示した。そこで、平成24年度では、キンギョ下垂体に存在するSL-α産生細胞、SL-β産生細胞およびSL-αとSL-β両方を産生する細胞の特徴付けを行った。一ヶ月間、白背地または黒背地で飼育したキンギョの下垂体におけるSL産生細胞の形態を免疫組織学的に観察し、比較した。 その結果、SL-α産生細胞は黒背地において肥大し、一方で、SL-β産生細胞は白背地において肥大していた。すなわち、SL-α産生細胞とSL-β産生細胞は背地色に応答し、相反して活性化することが示唆された。一方、SL-αとSL-β両方を産生する細胞の形態に背地色の影響は認められなかった。キンギョの初期発生段階における免疫組織学的観察の結果、SL-αとSL-β両方を産生する細胞は最初に発生するSL産生細胞であることが明らかとなった。SL-αとSL-β両方を産生する細胞の発生以降にSL-α産生細胞やSL-β産生細胞が出現することから、SL-αとSL-β両方を産生する細胞は、SL-α産生細胞やSL-β産生細胞へと分化する未分化な細胞であることが示唆された。


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