Curriculum Vitaes
  1. Researcher Search Results
  2. Naoya Asai

Naoya Asai

  (浅井 直也)

Profile Information

Affiliation
School of MedicineFaculty of Medicine, Fujita Health University
Degree
博士（医学）(名古屋大学)
J-GLOBAL ID
200901070978348285
researchmap Member ID
6000001683

Research Interests

 1

Research Areas

 1

Research History

 2

Papers

 107
  • Jumpei Yoshida, Takanori Hayashi, Eiji Munetsuna, Behnoush Khaledian, Fujiko Sueishi, Masahiro Mizuno, Masao Maeda, Takashi Watanabe, Kaori Ushida, Eiji Sugihara, Kazuyoshi Imaizumi, Kenji Kawada, Naoya Asai, Yohei Shimono
    Scientific reports, 14(1) 18494-18494, Aug 9, 2024  
    Adipocyte-cancer cell interactions promote tumor development and progression. Previously, we identified adipsin (CFD) and its downstream effector, hepatocyte growth factor (HGF), as adipokines that enhance adipocyte-breast cancer stem cell interactions. Here, we show that adipsin-dependent adipocyte maturation and the subsequent upregulation of HGF promote tumor invasion in breast cancers. Mature adipocytes, but not their precursors, significantly induced breast tumor cell migration and invasion in an adipsin expression-dependent manner. Promoters of tumor invasion, galectin 7 and matrix metalloproteinases, were significantly upregulated in cancer cells cocultured with mature adipocytes; meanwhile, their expression levels in cancer cells cocultured with adipocytes were reduced by adipsin knockout (Cfd KO) or a competitive inhibitor of CFD. Tumor growth and distant metastasis of mammary cancer cells were significantly suppressed when syngeneic mammary cancer cells were transplanted into Cfd KO mice. Histological analyses revealed reductions in capsular formation and tumor invasion at the cancer-adipocyte interface in the mammary tumors formed in Cfd KO mice. These findings indicate that adipsin-dependent adipocyte maturation may play an important role in adipocyte-cancer cell interaction and breast cancer progression.
  • Ryota Ando, Yukihiro Shiraki, Yuki Miyai, Hiroki Shimizu, Kazuhiro Furuhashi, Shun Minatoguchi, Katsuhiro Kato, Akira Kato, Tadashi Iida, Yasuyuki Mizutani, Kisuke Ito, Naoya Asai, Shinji Mii, Nobutoshi Esaki, Masahide Takahashi, Atsushi Enomoto
    The Journal of pathology, Oct 5, 2023  
    Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer-associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue-resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser-known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol-anchored membrane protein, as a PSC-specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin-positive (Meflin+ ) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue-resident fibroblasts. Three-dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin+ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin+ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin+ PSC-derived fibroblasts showed a distinctive morphology and distribution from Meflin+ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin+ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R-spondin 3 expression, thereby implying that Meflin+ PSCs and their lineage cells may support tissue recovery and Wnt/R-spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue-resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland.
  • 林 孝典, 吉田 淳平, 宗綱 栄二, Behnoush Khaledian, 前田 真男, 水野 真広, 牛田 かおり, 河田 健司, 浅井 直也, 下野 洋平
    日本癌学会総会記事, 82回 978-978, Sep, 2023  
  • Khaledian Behnoush, 吉田 淳平, 林 孝典, 水野 真広, 牛田 かおり, 前田 真男, 宗綱 栄二, 河田 健司, 浅井 直也, 下野 洋平, Shimono Yohei
    日本癌学会総会記事, 82回 1349-1349, Sep, 2023  
  • 林 孝典, 吉田 淳平, 宗綱 栄二, Behnoush Khaledian, 前田 真男, 水野 真広, 牛田 かおり, 河田 健司, 浅井 直也, 下野 洋平
    日本癌学会総会記事, 82回 978-978, Sep, 2023  
More

Misc.

 91
  • Kaori Ushida, Naoya Asai, Kozo Uchiyama, Atsushi Enomoto, Masahide Takahashi
    Pathology international, 68(4) 241-245, Apr, 2018  Peer-reviewed
    Embedding of tissue samples that maintains a desired orientation is critical for preparing sections suitable for diagnosis and study objectives. Methods to prepare tissue sections include: (i) paraffin embedding or snap-freezing followed by microtome or cryostat sectioning; and (ii) agarose embedding followed by cutting on a vibrating microslicer. Although these methods are useful for routine laboratory work, preparation of small and fragile tissues such as mouse organs, small human biopsy samples, and cultured floating spheres is difficult and requires special skills. In particular, tissue specimen orientation can be lost during embedding in molds and subsequent sectioning. Here, we developed a method using low melting temperature (LM) gelatin either alone or mixed with agarose to preliminarily embed collected tissues that are either prefixed or unfixed, followed by conventional fixation, paraffin embedding, freezing, and sectioning. The advantage of the method is that the LM gelatin and its mixture with agarose can be handled at room temperature but quickly hardens at 4°C, which allows embedding, trimming, and arranging of small and fragile tissues in a desired orientation and are compatible with traditional stainings. Thus, this method can have various laboratory applications and can be modified according to the needs of each laboratory.
  • Shiraki Yukihiro, Mii Shinji, Asai Naoya, Enomoto Atsushi, Momota Hiroyuki, Natsume Atsushi, Wakabayashi Toshihiko, Takahashi Masahide
    CANCER SCIENCE, 109 1130-1130-1130, Jan, 2018  
  • Yukihiro Shiraki, Shinji Mii, Atsushi Enomoto, Hiroyuki Momota, Yi-Peng Han, Takuya Kato, Kaori Ushida, Akira Kato, Naoya Asai, Yoshiki Murakumo, Kosuke Aoki, Hiromichi Suzuki, Fumiharu Ohka, Toshihiko Wakabayashi, Tomoki Todo, Seishi Ogawa, Atsushi Natsume, Masahide Takahashi
    The Journal of pathology, 243(4) 468-480, Dec, 2017  Peer-reviewed
    In the progression of glioma, tumour cells often exploit the perivascular microenvironment to promote their survival and resistance to conventional therapies. Some of these cells are considered to be brain tumour stem cells (BTSCs); however, the molecular nature of perivascular tumour cells has not been specifically clarified because of the complexity of glioma. Here, we identified CD109, a glycosylphosphatidylinositol-anchored protein and regulator of multiple signalling pathways, as a critical regulator of the progression of lower-grade glioma (World Health Organization grade II/III) by clinicopathological and whole-genome sequencing analysis of tissues from human glioma. The importance of CD109-positive perivascular tumour cells was confirmed not only in human lower-grade glioma tissues but also in a mouse model that recapitulated human glioma. Intriguingly, BTSCs isolated from mouse glioma expressed high levels of CD109. CD109-positive BTSCs exerted a proliferative effect on differentiated glioma cells treated with temozolomide. These data reveal the significance of tumour cells that populate perivascular regions during glioma progression, and indicate that CD109 is a potential therapeutic target for the disease. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
  • Maki Takagishi, Masato Sawada, Shinya Ohata, Naoya Asai, Atsushi Enomoto, Kunihiko Takahashi, Liang Weng, Kaori Ushida, Hosne Ara, Shigeyuki Matsui, Kozo Kaibuchi, Kazunobu Sawamoto, Masahide Takahashi
    Cell reports, 20(4) 960-972, Jul 25, 2017  Peer-reviewed
    Motile cilia in ependymal cells, which line the cerebral ventricles, exhibit a coordinated beating motion that drives directional cerebrospinal fluid (CSF) flow and guides neuroblast migration. At the apical cortex of these multi-ciliated cells, asymmetric localization of planar cell polarity (PCP) proteins is required for the planar polarization of microtubule dynamics, which coordinates cilia orientation. Daple is a disheveled-associating protein that controls the non-canonical Wnt signaling pathway and cell motility. Here, we show that Daple-deficient mice present hydrocephalus and their ependymal cilia lack coordinated orientation. Daple regulates microtubule dynamics at the anterior side of ependymal cells, which in turn orients the cilial basal bodies required for the directional cerebrospinal fluid flow. These results demonstrate an important role for Daple in planar polarity in motile cilia and provide a framework for understanding the mechanisms and functions of planar polarization in the ependymal cells.
  • Daisuke Kuga, Kaori Ushida, Shinji Mii, Atsushi Enomoto, Naoya Asai, Masato Nagino, Masahide Takahashi, Masato Asai
    The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society, 65(6) 347-366, Jun, 2017  Peer-reviewed
    Tuft cells (TCs) are minor components of gastrointestinal epithelia, characterized by apical tufts and spool-shaped somas. The lack of reliable TC-markers has hindered the elucidation of its role. We developed site-specific and phosphorylation-status-specific antibodies against Girdin at tyrosine-1798 (pY1798) and found pY1798 immunostaining of mouse jejunum clearly depicted epithelial cells closely resembling TCs. This study aimed to validate pY1798 as a TC-marker. Double-fluorescence staining of intestines was performed with pY1798 and known TC-markers, for example, hematopoietic-prostaglandin-D-synthase (HPGDS), or doublecortin-like kinase 1 (DCLK1). Odds ratios (ORs) were calculated from cell counts to determine whether two markers were attracting (OR<1) or repelling (OR>1). In consequence, pY1798 signals strongly attracted those of known TC-markers. ORs for HPGDS in mouse stomach, small intestine, and colon were 0 for all, and 0.08 for DCLK1 in human small intestine. pY1798-positive cells in jejunum were distinct from other minor epithelial cells, including goblet, Paneth, and neuroendocrine cells. Thus, pY1798 was validated as a TC-marker. Interestingly, apoptosis inducers significantly increased relative TC frequencies despite the absence of proliferation at baseline. In conclusion, pY1798 is a novel TC-marker. Selective tyrosine phosphorylation and possible resistance to apoptosis inducers implied the activation of certain kinase(s) in TCs, which may become a clue to elucidate the enigmatic roles of TCs. .
  • Yi-Peng Han, Atsushi Enomoto, Yukihiro Shiraki, Shen-Qi Wang, Xiaoze Wang, Shinya Toyokuni, Naoya Asai, Kaori Ushida, Hosne Ara, Fumiharu Ohka, Toshihiko Wakabayashi, Jie Ma, Atsushi Natsume, Masahide Takahashi
    Neuro-oncology, 19(5) 636-647, May 1, 2017  Peer-reviewed
    Background: The significance of mammalian target of rapamycin complex 1 (mTORC1) activity in the maintenance of cancer stem cells (CSCs) remains controversial. Previous findings showed that mTORC1 activation depleted the population of leukemia stem cells in leukemia, while maintaining the stemness in pancreatic CSCs. The purpose of this study was to examine the currently unknown role and significance of mTORC1 activity in brain tumor stem cells (BTSCs). Methods: Basal mTORC1 activity and its kinetics were investigated in BTSC clones isolated from patients with glioblastoma and their differentiated progenies (DIFFs). The effects of nutrient deprivation and the mTORC1 inhibitors on cell proliferation were compared between the BTSCs and DIFFs. Tissue sections from patients with brain gliomas were examined for expression of BTSC markers and mTORC1 activity by immunohistochemistry. Results: BTSCs presented lower basal mTORC1 activity under each culture condition tested and a more rapid decline of mTORC1 activity after nutrient deprivation than observed in DIFFs. The self-renewal capacity of BTSCs was unaffected by mTORC1 inhibition, whereas it effectively suppressed DIFF proliferation. In agreement, immunohistochemical staining of glioma tissues revealed low mTORC1 activity in tumor cells positive for BTSC markers. In in vitro culture, BTSCs exhibited resistance to the antitumor agent temozolomide. Conclusions: Our findings indicated the importance of low mTORC1 activity in maintaining the undifferentiated state of BTSCs, implicating the relevance of manipulating mTORC1 activity when developing future strategies that target BTSCs.
  • 48(7) 343-346, Jul, 2016  
  • Michael S Nahorski, Masato Asai, Emma Wakeling, Alasdair Parker, Naoya Asai, Natalie Canham, Susan E Holder, Ya-Chun Chen, Joshua Dyer, Angela F Brady, Masahide Takahashi, C Geoffrey Woods
    Brain : a journal of neurology, 139(Pt 4) 1036-44, Apr, 2016  Peer-reviewed
    Progressive encephalopathy with oedema, hypsarrhythmia and optic atrophy (PEHO) syndrome is a rare Mendelian phenotype comprising severe retardation, early onset epileptic seizures, optic nerve/cerebellar atrophy, pedal oedema, and early death. Atypical cases are often known as PEHO-like, and there is an overlap with 'early infantile epileptic encephalopathy'. PEHO is considered to be recessive, but surprisingly since initial description in 1991, no causative recessive gene(s) have been described. Hence, we report a multiplex consanguineous family with the PEHO phenotype where affected individuals had a homozygous frame-shift deletion in CCDC88A (c.2313delT, p.Leu772*ter). Analysis of cDNA extracted from patient lymphocytes unexpectedly failed to show non-sense mediated decay, and we demonstrate that the mutation produces a truncated protein lacking the crucial C-terminal half of CCDC88A (girdin). To further investigate the possible role of CCDC88A in human neurodevelopment we re-examined the behaviour and neuroanatomy of Ccdc88a knockout pups. These mice had mesial-temporal lobe epilepsy, microcephaly and corpus callosum deficiency, and by postnatal Day 21, microcephaly; the mice died at an early age. As the mouse knockout phenotype mimics the human PEHO phenotype this suggests that loss of CCDC88A is a cause of the PEHO phenotype, and that CCDC88A is essential for multiple aspects of normal human neurodevelopment.
  • Keiko Maeda, Atsushi Enomoto, Akitoshi Hara, Naoya Asai, Takeshi Kobayashi, Asuka Horinouchi, Shoichi Maruyama, Yuichi Ishikawa, Takahiro Nishiyama, Hitoshi Kiyoi, Takuya Kato, Kenju Ando, Liang Weng, Shinji Mii, Masato Asai, Yasuyuki Mizutani, Osamu Watanabe, Yoshiki Hirooka, Hidemi Goto, Masahide Takahashi
    Scientific reports, 6 22288-22288, Feb 29, 2016  Peer-reviewed
    Bone marrow-derived mesenchymal stromal cells (BM-MSCs) in culture are derived from BM stromal cells or skeletal stem cells. Whereas MSCs have been exploited in clinical medicine, the identification of MSC-specific markers has been limited. Here, we report that a cell surface and secreted protein, Meflin, is expressed in cultured MSCs, fibroblasts and pericytes, but not other types of cells including epithelial, endothelial and smooth muscle cells. In vivo, Meflin is expressed by immature osteoblasts and chondroblasts. In addition, Meflin is found on stromal cells distributed throughout the BM, and on pericytes and perivascular cells in multiple organs. Meflin maintains the undifferentiated state of cultured MSCs and is downregulated upon their differentiation, consistent with the observation that Meflin-deficient mice exhibit increased number of osteoblasts and accelerated bone development. In the bone and BM, Meflin is more highly expressed in primitive stromal cells that express platelet-derived growth factor receptor α and Sca-1 than the Sca-1-negative adipo-osteogenic progenitors, which create a niche for hematopoiesis. Those results are consistent with a decrease in the number of clonogenic colony-forming unit-fibroblasts within the BM of Meflin-deficient mice. These preliminary data suggest that Meflin is a potential marker for cultured MSCs and their source cells in vivo.
  • A. Enomoto, N. Asai, T. Kobayashi, N. Nakamura, M. Takahashi
    MOLECULAR BIOLOGY OF THE CELL, 27, 2016  
  • Kenji Omori, Masato Asai, Daisuke Kuga, Kaori Ushida, Tetsushi Izuchi, Shinji Mii, Atsushi Enomoto, Naoya Asai, Masato Nagino, Masahide Takahashi
    Biochemical and biophysical research communications, 458(4) 934-40, Mar 20, 2015  Peer-reviewed
    The mammalian protein Girdin interacts with several key molecules such as actin, and it functions as a regulator of the cytoskeleton. Silencing of Girdin mRNA results in defective migration in a variety of cultured cells. Moreover, knockout of Girdin causes phenotypes related to defective migration, including hypoplasia of olfactory bulbs and a widened rostral migratory stream (RMS) in mice. To elucidate the molecular basis underlying cellular migration, we generated site- and phosphorylation state-specific antibodies against human Girdin peptides carrying four putative phosphorylation sites (serine1386 [S1386], S1416, tyrosine1764 [Y1764] and Y1798) that had been identified by mutagenesis analyses or mass spectrometric studies. We found that these residues were phosphorylated in an epidermal growth factor (EGF)-dependent manner. Among the four antibodies we developed, the antibody that targeted Girdin when phosphorylated at Y1798 (pY1798) worked well for immunohistochemistry of paraffin-embedded tissues as well as for cultured cells. Immunocytochemistry of HEK293FT cells transfected with an EGF receptor expression plasmid exhibited punctate signals with pY1798. These signals colocalized with those of endocytosed EGF receptors after EGF stimulation. Signals from pY1798 were also observed on lamellipodia, filopodia, focal adhesion and stress fibers in NIH3T3 cells under conventional culture conditions. Immunohistochemistry of paraffin-embedded mouse brain at P14 using anti-pY1798 antibody displayed signals at the hilum-side (internal side) of the dentate gyrus of the hippocampus, the RMS, the accessory olfactory bulb and the olfactory bulb in which Girdin expression was detected. Primary culture of RMS neurons showed punctate signals of pY1798 at the tips of leading processes as well as in the cytoplasm, whereas no signals were observed when neurons were treated with Src inhibitor, PP2. Our data revealed the changes in the phosphorylation status of Y1798 in Girdin when it associated with migration-related structures in vitro and in vivo.
  • Yumiko Yamamura, Naoya Asai, Atsushi Enomoto, Takuya Kato, Shinji Mii, Yuji Kondo, Kaori Ushida, Kaoru Niimi, Nobuyuki Tsunoda, Masato Nagino, Shu Ichihara, Koichi Furukawa, Kengo Maeda, Toyoaki Murohara, Masahide Takahashi
    Cancer research, 75(5) 813-23, Mar 1, 2015  Peer-reviewed
    PI3K-Akt signaling is critical for the development, progression, and metastasis of malignant tumors, but its role in the tumor microenvironment has been relatively little studied. Here, we report that the Akt substrate Girdin, an actin-binding protein that regulates cell migration, is expressed and activated by Akt phosphorylation in cancer-associated fibroblasts (CAF) and blood vessels within the tumor microenvironment. Lewis lung tumors grafted into mice defective in Akt-mediated Girdin phosphorylation (SA transgenic mice) exhibited a decrease in both CAF infiltration and tumor growth, compared with wild-type (WT) host control animals. Contrasting with the findings of other studies, we found that Akt-dependent phosphorylation of Girdin was not a rate-limiting step in the growth of endothelial cells. In addition, Lewis lung tumors displayed limited outgrowth when cotransplanted with CAF derived from tumor-bearing SA transgenic mice, compared with CAF derived from tumor-bearing WT mice. Collectively, our results revealed a role for Akt-mediated Girdin phosphorylation in CAF during tumor progression, highlighting the need to inhibit Akt function in both tumor cells and cells that comprise the tumor microenvironment.
  • Tsuyoshi Nakai, Taku Nagai, Motoki Tanaka, Norimichi Itoh, Naoya Asai, Atsushi Enomoto, Masato Asai, Shinnosuke Yamada, Ali Bin Saifullah, Masahiro Sokabe, Masahide Takahashi, Kiyofumi Yamada
    The Journal of neuroscience : the official journal of the Society for Neuroscience, 34(45) 14995-5008, Nov 5, 2014  Peer-reviewed
    Synaptic plasticity in hippocampal neurons has been thought to represent a variety of memories. Although accumulating evidence indicates a crucial role of BDNF/TrkB/Akt signaling in the synaptic plasticity of the hippocampus, the mechanism by which Akt, a serine/threonine kinase, controls activity-dependent neuronal plasticity remains unclear. Girdin (also known as APE, GIV, and HkRP1), an actin-binding protein involved both in the remodeling of the actin cytoskeleton and in cell migration, has been identified as a substrate of Akt. Previous studies have demonstrated that deficit of neuronal migration in the hippocampus of Girdin-deficient (Girdin(-/-)) mice is independent on serine phosphorylation of Girdin at S1416 (Girdin S1416) by Akt. In the present study, we focused on the role of Girdin S1416 phosphorylation in BDNF/TrkB/Akt signaling associated with synaptic plasticity. We found that Girdin in the hippocampus was phosphorylated at S1416 in an activity-dependent manner. Phosphorylation-deficient knock-in mice (Girdin(SA/SA) mice), in which S1416 is replaced with alanine, exhibited shrinkage of spines, deficit of hippocampal long-term potentiation, and memory impairment. These phenotypes of Girdin(SA/SA) mice resembled those of Girdin(+/-) mice, which have 50% loss of Girdin expression. Furthermore, Girdin interacted with Src kinase and NR2B subunit of NMDA receptor, leading to phosphorylation of the NR2B subunit and NMDA receptor activation. Our findings suggest that Girdin has two different functions in the hippocampus: Akt-independent neuronal migration and Akt-dependent NR2B phosphorylation through the interaction with Src, which is associated with synaptic plasticity in the hippocampus underlying memory formation.
  • Yoshiki Murakumo, Naoki Watanabe, Shinji Mii, Masato Asai, Naoya Asai, Kaoru Niimi, Takuya Kato, Atsushi Enomoto, Masahide Takahashi
    CANCER RESEARCH, 74(19), Oct, 2014  
  • Liang Weng, Atsushi Enomoto, Hiroshi Miyoshi, Kiyofumi Takahashi, Naoya Asai, Nobuhiro Morone, Ping Jiang, Jian An, Takuya Kato, Keisuke Kuroda, Takashi Watanabe, Masato Asai, Maki Ishida-Takagishi, Yoshiki Murakumo, Hideki Nakashima, Kozo Kaibuchi, Masahide Takahashi
    The EMBO journal, 33(18) 2098-112, Sep 17, 2014  Peer-reviewed
    In clathrin-mediated endocytosis (CME), specificity and selectivity for cargoes are thought to be tightly regulated by cargo-specific adaptors for distinct cellular functions. Here, we show that the actin-binding protein girdin is a regulator of cargo-selective CME. Girdin interacts with dynamin 2, a GTPase that excises endocytic vesicles from the plasma membrane, and functions as its GTPase-activating protein. Interestingly, girdin depletion leads to the defect in clathrin-coated pit formation in the center of cells. Also, we find that girdin differentially interacts with some cargoes, which competitively prevents girdin from interacting with dynamin 2 and confers the cargo selectivity for CME. Therefore, girdin regulates transferrin and E-cadherin endocytosis in the center of cells and their subsequent polarized intracellular localization, but has no effect on integrin and epidermal growth factor receptor endocytosis that occurs at the cell periphery. Our results reveal that girdin regulates selective CME via a mechanism involving dynamin 2, but not by operating as a cargo-specific adaptor.
  • Haruko Ota, Takao Hikita, Masato Sawada, Tomoki Nishioka, Mami Matsumoto, Masayuki Komura, Akihisa Ohno, Yukiyo Kamiya, Takuya Miyamoto, Naoya Asai, Atsushi Enomoto, Masahide Takahashi, Kozo Kaibuchi, Kazuya Sobue, Kazunobu Sawamoto
    Nature communications, 5 4532-4532, Jul 30, 2014  Peer-reviewed
    Throughout life, new neurons generated in the ventricular-subventricular zone take the long journey to the olfactory bulb. The intracellular mechanisms that precisely control the neurons' migration speed, enabling their well-organized movement, remain unclear. Rho signalling is known to affect the morphology and movement of various cell types, including neurons. Here we identify Gem-interacting protein (Gmip), a RhoA-specific GTPase-activating protein, as a key factor in saltatory neuronal migration. RhoA is activated at the proximal leading process of migrating neurons, where Gmip is also localized and negatively regulates RhoA. Gmip controls the saltatory movement of neurons that regulate their migration speed and 'stop' positions in the olfactory bulb, thereby altering the neural circuitry. This study demonstrates that Gmip serves as a brake for the RhoA-mediated movement of neuronal somata, and highlights the significance of speed control in the well-organized neuronal migration and the maintenance of neuronal circuits in the postnatal brain.
  • Toyoaki Murohara, Kengo Maeda, Hiroshi Miyake, Naoya Asai, Atsushi Enomoto, Masahide Takahashi
    JOURNAL OF GENE MEDICINE, 16(7-8) 210-210, Jul, 2014  
  • Cristina Cebrian, Naoya Asai, Vivette D'Agati, Frank Costantini
    Cell reports, 7(1) 127-37, Apr 10, 2014  Peer-reviewed
    Nephrons, the functional units of the kidney, develop from progenitor cells (cap mesenchyme [CM]) surrounding the epithelial ureteric bud (UB) tips. Reciprocal signaling between UB and CM induces nephrogenesis and UB branching. Although low nephron number is implicated in hypertension and renal disease, the mechanisms that determine nephron number are obscure. To test the importance of nephron progenitor cell number, we genetically ablated 40% of these cells, asking whether this would limit kidney size and nephron number or whether compensatory mechanisms would allow the developing organ to recover. The reduction in CM cell number decreased the rate of branching, which in turn allowed the number of CM cells per UB tip to normalize, revealing a self-correction mechanism. However, the retarded UB branching impaired kidney growth, leaving a permanent nephron deficit. Thus, the number of fetal nephron progenitor cells is an important determinant of nephron endowment, largely via its effect on UB branching.
  • Naoki Watanabe, Shinji Mii, Naoya Asai, Masato Asai, Kaoru Niimi, Kaori Ushida, Takuya Kato, Atsushi Enomoto, Hideshi Ishii, Masahide Takahashi, Yoshiki Murakumo
    The Journal of biological chemistry, 288(15) 10459-71, Apr 12, 2013  Peer-reviewed
    REV7 (also known as MAD2L2 and MAD2B) is involved in DNA repair, cell cycle regulation, gene expression, and carcinogenesis. In vitro studies show that REV7 interacts with several proteins and regulates their function. It has been reported that human REV7 is highly expressed in the adult testis by Northern blot analysis. However, the significance of REV7 in mammalian development has not been elucidated. Here, we present analyses of REV7-deficient (Rev7(-/-)) mice to clarify the significance of Rev7 in mouse development. In WT mice (Rev7(+/+)), Rev7 expression was ubiquitously observed in the embryo and confined to germ cells in the testes after birth. Rev7(-/-) mice exhibited growth retardation and a partial embryonic lethal phenotype. Mice that survived to adulthood were infertile in both sexes and showed germ cell aplasia in the testes and ovaries. Analyses of Rev7(-/-) embryos revealed that primordial germ cells (PGCs) were present at embryonic day 8.5 (E8.5). However, progressive loss of PGCs was observed during migration, and PGCs were absent in the genital ridges at E13.5. An increase of apoptotic cells was detected not only among PGCs but also in the forebrain of the Rev7(-/-) embryo, whereas cell proliferation was unaffected. Moreover, DNA damage accumulation and increased levels of histone methylation were detected in Rev7(-/-) embryos, and expression of Oct4 and Nanog was deregulated by REV7 deficiency at E8.5. These findings indicate that Rev7 is essential for PGC maintenance by prevention of apoptotic cell death in the mouse.
  • Takanori Ito, Keiichi Komeima, Tetsuhiro Yasuma, Atsushi Enomoto, Naoya Asai, Masato Asai, Sayoko Iwase, Masahide Takahashi, Hiroko Terasaki
    The American journal of pathology, 182(2) 586-96, Feb, 2013  Peer-reviewed
    Vascular endothelial growth factor (VEGF) is recognized as a principal mediator of vessel growth. VEGF regulates various endothelial cellular processes, including cell migration, proliferation, and survival, through the serine threonine protein kinase Akt. The Akt substrate girdin, an actin-binding protein, is known to regulate VEGF-mediated postnatal angiogenesis. However, the role of girdin and its phosphorylation in neonatal retinal vascular development and ocular pathological neovascularization in vivo has not been elucidated. In the present study, therefore, we investigated these processes using Girdin(+/-) mice lacking one copy of the girdin gene and girdin S1416A knockin (Girdin-KI(SA/SA)) mice in which the phosphorylation site of girdin is completely disrupted. We used three mouse models of pathological ocular neovascularization: oxygen-induced retinopathy (a mouse model of ischemic retinopathies), laser-induced choroidal neovascularization, and a human VEGF transgenic mouse that overexpresses human VEGF specifically in photoreceptor cells and generates pathological neovascularization in the retina. Neonatal vascular development was delayed and pathological neovascularization was decreased in both Girdin(+/-) mice and Girdin-KI(SA/SA) mice. These results demonstrate that girdin and its phosphorylation play an important role in neonatal vascular development and in pathological neovascularization in the retina.
  • Tsuyoshi Nakai, Taku Nagai, Motoki Tanaka, Naoya Asai, Atsushi Enomoto, Masahiro Sokabe, Masahide Takahashi, Kiyofumi Yamada
    JOURNAL OF PHARMACOLOGICAL SCIENCES, 121 64P-64P, 2013  
  • Masato Asai, Naoya Asai, Ayana Murata, Hirofumi Yokota, Kenji Ohmori, Shinji Mii, Atsushi Enomoto, Yoshiki Murakumo, Masahide Takahashi
    Biochemical and biophysical research communications, 426(4) 533-8, Oct 5, 2012  Peer-reviewed
    Girdin is an Akt substrate and actin-binding protein. Mice with germ-line deletions of Girdin (a non-conditional knockout, (ncKO)) exhibit complete postnatal lethality accompanied by growth retardation and neuronal cell migration defects, which results in hypoplasia of the olfactory bulb and granule cell dispersion in the dentate gyrus. However, the physiological and molecular abnormalities in Girdin ncKO mice are not fully understood. In this study, we first defined the distribution of Girdin in neonates (P1) and adults (6months or older) using β-galactosidase activity in tissues from ncKO mice. The results indicate that Girdin is expressed throughout the nervous system (brain, spinal cord, enteric and autonomic nervous systems). In addition, β-galactosidase activity was detected in non-neural tissues, particularly in tissues with high tensile force, such as tendons, heart valves, and skeletal muscle. In order to identify the cellular population where the Girdin ncKO phenotype originates, newly generated Girdin flox mice were crossed with nestin promoter-driven Cre transgenic mice to obtain Girdin conditional knockout (cKO) mice. The phenotype of Girdin cKO mice was almost identical to ncKO mice, including postnatal lethality, growth retardation and decreased neuronal migration. Our findings indicate that loss of Girdin in the nestin cell lineage underlies the phenotype of Girdin ncKO mice.
  • Maiko Horio, Takuya Kato, Shinji Mii, Atsushi Enomoto, Masato Asai, Naoya Asai, Yoshiki Murakumo, Kiyosumi Shibata, Fumitaka Kikkawa, Masahide Takahashi
    Cancer medicine, 1(2) 218-29, Oct, 2012  Peer-reviewed
    Resistance to platinum- and taxane-based chemotherapy is a major cause of treatment failure in ovarian cancer. Thus, it is necessary to develop a predictive marker and molecular target for overcoming drug resistance in ovarian cancer treatment. In a previous report, using an in vitro model, we found that the RET finger protein (RFP) (also known as tripartite motif-containing protein 27, TRIM27) confers cancer cell resistance to anticancer drugs. However, the significance of RFP expression in cancer patients remains elusive. In this study, we showed that RFP was expressed in 62% of ovarian cancer patients and its positivity significantly correlated with drug resistance. Consistent with clinical data, depletion of RFP by RNA interference (RNAi) in ovarian cancer cell lines, SKOV3 and HEY, significantly increased carboplatin- or paclitaxel-induced apoptosis and resulted in reduced anticancer drug resistance. In a nude mouse tumor xenograft model, inoculated RFP-knockdown ovarian cancer cells exhibited lower carboplatin resistance than control cells. These findings suggest that RFP could be a predictive marker for chemoresistance in ovarian cancer patients and also a candidate for a molecular-targeted agent.
  • Shinji Mii, Yoshiki Murakumo, Naoya Asai, Mayumi Jijiwa, Sumitaka Hagiwara, Takuya Kato, Masato Asai, Atsushi Enomoto, Kaori Ushida, Sayaka Sobue, Masatoshi Ichihara, Masahide Takahashi
    The American journal of pathology, 181(4) 1180-9, Oct, 2012  Peer-reviewed
    CD109, a glycosylphosphatidylinositol-anchored glycoprotein, is highly expressed in several types of human cancer tissues, in particular, squamous cell carcinomas. In normal human tissues, human CD109 expression is limited to certain cell types including myoepithelial cells of the mammary, lacrimal, salivary, and bronchial glands and basal cells of the prostate and bronchial epithelium. Although CD109 has been reported to negatively regulate transforming growth factor-β signaling in keratinocytes in vitro, its physiologic role in vivo remains largely unknown. To investigate the function of CD109 in vivo, we generated CD109-deficient (CD109(-/-)) mice. Although CD109(-/-) mice were born normally, transient impairment of hair growth was observed. At histologic analysis, kinked hair shafts, ectatic hair follicles with an accumulation of sebum, and persistent hyperplasia of the epidermis and sebaceous glands were observed in CD109(-/-) mice. Immunohistochemical analysis revealed thickening of the basal and suprabasal layers in the epidermis of CD109(-/-) mice, which is where endogenous CD109 is expressed in wild-type mice. Although CD109 was reported to negatively regulate transforming growth factor-β signaling, no significant difference in levels of Smad2 phosphorylation was observed in the epidermis between wild-type and CD109(-/-) mice. Instead, Stat3 phosphorylation levels were significantly elevated in the epidermis of CD109(-/-) mice compared with wild-type mice. These results suggest that CD109 regulates differentiation of keratinocytes via a signaling pathway involving Stat3.
  • Maki Ishida-Takagishi, Atsushi Enomoto, Naoya Asai, Kaori Ushida, Takashi Watanabe, Takahiko Hashimoto, Takuya Kato, Liang Weng, Shinji Matsumoto, Masato Asai, Yoshiki Murakumo, Kozo Kaibuchi, Akira Kikuchi, Masahide Takahashi
    Nature communications, 3 859-859, May 29, 2012  Peer-reviewed
    Dishevelled is the common mediator of canonical and non-canonical Wnt signalling pathways, which are important for embryonic development, tissue maintenance and cancer progression. In the non-canonical Wnt signalling pathway, the Rho family of small GTPases acting downstream of Dishevelled has essential roles in cell migration. The mechanisms by which the non-canonical Wnt signalling pathway regulates Rac activation remain unknown. Here we show that Daple (Dishevelled-associating protein with a high frequency of leucine residues) regulates Wnt5a-mediated activation of Rac and formation of lamellipodia through interaction with Dishevelled. Daple increases the association of Dishevelled with an isoform of atypical protein kinase C, consequently promoting Rac activation. Accordingly, Daple deficiency impairs migration of fibroblasts and epithelial cells during wound healing in vivo. These findings indicate that Daple interacts with Dishevelled to direct the Dishevelled/protein kinase λ protein complex to activate Rac, which in turn mediates the non-canonical Wnt signalling pathway required for cell migration.
  • Shinji Mii, Yoshiki Murakumo, Naoya Asai, Masato Asai, Masahide Takahashi
    CANCER RESEARCH, 72, Apr, 2012  
  • Nobutaka Ohgami, Michiru Ida-Eto, Naomi Sakashita, Michihiko Sone, Tsutomu Nakashima, Keiji Tabuchi, Tomofumi Hoshino, Atsuyoshi Shimada, Toyonori Tsuzuki, Masahiko Yamamoto, Gen Sobue, Mayumi Jijiwa, Naoya Asai, Akira Hara, Masahide Takahashi, Masashi Kato
    Neurobiology of aging, 33(3) 626.e25-34, Mar, 2012  Peer-reviewed
    c-Ret has been shown to be crucial for neural development and survival. We have recently shown that complete impairment of tyrosine 1062 (Y1062)-phosphorylation in c-Ret causes congenital hearing loss with neurodegeneration of spiral ganglion neurons (SGNs) in homozygous c-Ret knockin mice (c-Ret-KI(Y1062F/Y1062F)-mice). However, there is no information to link c-Ret and age-related hearing loss. Here we show that partial impairment of Y1062-phosphorylation in c-Ret accelerates age-related hearing loss in heterozygous c-Ret Y1062F knockin mice (c-Ret-KI(Y1062F/+)-mice). In contrast, complete impairment of serine 697 (S697)-phosphorylation in c-Ret did not affect hearing levels in 10-month-old homozygous c-Ret S697A knockin mice (c-Ret-KI(S697A/S697A)-mice). The hearing loss involved late-onset neurodegeneration of spiral ganglion neurons in c-Ret-KI(Y1062F/+)-mice. Morphological abnormalities in inner- and outer-hair cells and the stria vascularis in c-Ret-KI(Y1062F/+)-mice were undetectable. The acceleration of age-related hearing loss in c-Ret-KI(Y1062F/+)-mice was rescued by introducing constitutively activated RET. Thus, our results suggest that c-Ret is a novel age-related hearing loss-related molecule in mice. Our results suggest that these hearing losses partially share a common pathogenesis that is monogenetically caused by a single point mutation (Y1062F) in c-Ret.
  • T. Kato, A. Enomoto, H. Haga, S. Ishida, M. Asai, N. Asai, M. Takahashi
    MOLECULAR BIOLOGY OF THE CELL, 23, 2012  
  • Tsuyoshi Nakai, Taku Nagai, Naoya Asai, Atsushi Enomoto, Masahide Takahashi, Kiyofumi Yamada
    JOURNAL OF PHARMACOLOGICAL SCIENCES, 118 140P-140P, 2012  
  • 北村彩, 榎本篤, 浅井直也, 下山芳江, 川島希, 高橋義行, 小島勢二, 中村栄男, 高橋雅英
    日本病理学会会誌, 101(1), 2012  
  • Ohgami N, Ida M, Shimotake T, Sakashita N, Sone M, Nakashima T, Tabuchi K, Hoshino T, Shimada A, Tsuzuki T, Yamamoto M, Sobue G, Jijiwa M, Asai N, Hara A, Takahashi M, Kato M
    Proc Natl Acad Sci USA, 107(29) 13051-6, 2012  
  • Kei Ohara, Atsushi Enomoto, Takuya Kato, Takahiko Hashimoto, Mayu Isotani-Sakakibara, Naoya Asai, Maki Ishida-Takagishi, Liang Weng, Masanori Nakayama, Takashi Watanabe, Katsuhiro Kato, Kozo Kaibuchi, Yoshiki Murakumo, Yoshiki Hirooka, Hidemi Goto, Masahide Takahashi
    PloS one, 7(5) e36681, 2012  Peer-reviewed
    Cell migration is a critical cellular process that determines embryonic development and the progression of human diseases. Therefore, cell- or context-specific mechanisms by which multiple promigratory proteins differentially regulate cell migration must be analyzed in detail. Girdin (girders of actin filaments) (also termed GIV, Gα-interacting vesicle associated protein) is an actin-binding protein that regulates migration of various cells such as endothelial cells, smooth muscle cells, neuroblasts, and cancer cells. Here we show that Girdin regulates the establishment of cell polarity, the deregulation of which may result in the disruption of directional cell migration. We found that Girdin interacts with Par-3, a scaffolding protein that is a component of the Par protein complex that has an established role in determining cell polarity. RNA interference-mediated depletion of Girdin leads to impaired polarization of fibroblasts and mammary epithelial cells in a way similar to that observed in Par-3-depleted cells. Accordingly, the expression of Par-3 mutants unable to interact with Girdin abrogates cell polarization in fibroblasts. Further biochemical analysis suggests that Girdin is present in the Par protein complex that includes Par-3, Par-6, and atypical protein kinase C. Considering previous reports showing the role of Girdin in the directional migration of neuroblasts, network formation of endothelial cells, and cancer invasion, these data may provide a specific mechanism by which Girdin regulates cell movement in biological contexts that require directional cell movement.
  • Yoshiaki Morishita, Hiroshi Arima, Maiko Hiroi, Masayuki Hayashi, Daisuke Hagiwara, Naoya Asai, Nobuaki Ozaki, Yoshihisa Sugimura, Hiroshi Nagasaki, Akira Shiota, Masahide Takahashi, Yutaka Oiso
    Endocrinology, 152(12) 4846-55, Dec, 2011  Peer-reviewed
    Familial neurohypophysial diabetes insipidus (FNDI) is caused by mutations in the gene locus of arginine vasopressin (AVP), an antidiuretic hormone. Although the carriers are normal at birth, polyuria and polydipsia appear several months or years later. Previously, we made mice possessing a mutation causing FNDI and reported that the mice manifested progressive polyuria as do the patients with FNDI. Here, we report that decreases in AVP mRNA expression in the supraoptic nucleus were accompanied by shortening of the AVP mRNA poly(A) tail length in the FNDI mice, a case in which aggregates accumulated in the endoplasmic reticulum (ER) of the hypothalamic AVP neurons. Expression levels of AVP heteronuclear RNA in the supraoptic nucleus, a sensitive indicator for gene transcription, were not significantly different between FNDI and wild-type mice. Incubation of hypothalamic explants of wild-type mice with ER stressors (thapsigargin and tunicamycin) caused shortening of the poly(A) tail length of AVP and oxytocin mRNA, accompanied by decreases in their expression. On the other hand, an ER stress-reducing molecule (tauroursodeoxycholate) increased the poly(A) tail length as well as the expression levels of AVP and oxytocin mRNA. These data reveal a novel mechanism by which ER stress decreases poly(A) tail length of neurohypophysial hormones, probably to reduce the load of unfolded proteins.
  • Shoji Saito, Yoshiki Murakumo, Toyonori Tsuzuki, Atsushi Dambara, Takuya Kato, Atsushi Enomoto, Naoya Asai, Shoichi Maruyama, Seiichi Matsuo, Masahide Takahashi
    Human pathology, 42(6) 848-58, Jun, 2011  Peer-reviewed
    The glial cell line-derived neurotrophic factor (GDNF)-RET signaling pathway plays an important role in kidney development. We have previously identified a novel zinc finger protein, glial cell line-derived neurotrophic factor-inducible zinc finger protein 1 (GZF1), whose expression was induced in the human neuroblastoma cell line TGW expressing RET by GDNF stimulation and was also detected in mouse metanephric kidney. In the present study, we examined the immunohistochemical expression of GZF1 in normal human kidney and various kidney diseases including chronic kidney disease, acute kidney injury, and cancers, and assessed the clinical significance of GZF1 expression. In the normal kidney, GZF1 was highly expressed only in the proximal tubular epithelial cells that were also positive for angiotensin-converting enzyme. We also evaluated GZF1 expression in various kidney diseases including membranous nephropathy, minimal change nephrotic syndrome with or without acute kidney injury, immunoglobulin A nephropathy, diabetic nephropathy, acute tubular necrosis, and antineutrophil cytoplasmic antibody-related glomerulonephritis. We found that decreased expression of GZF1 was associated with an increase in tubulointerstitial damage and serum creatinine levels. In addition, GZF1 expression was undetectable or very low in most cases of renal cell carcinomas and Wilms tumors. These findings suggest that GZF1 represents a new marker for renal proximal tubules and that there is an inverse correlation between the expression level of GZF1 and tubular function.
  • Yun Wang, Naoko Kaneko, Naoya Asai, Atsushi Enomoto, Mayu Isotani-Sakakibara, Takuya Kato, Masato Asai, Yoshiki Murakumo, Haruko Ota, Takao Hikita, Takashi Namba, Keisuke Kuroda, Kozo Kaibuchi, Guo-li Ming, Hongjun Song, Kazunobu Sawamoto, Masahide Takahashi
    The Journal of neuroscience : the official journal of the Society for Neuroscience, 31(22) 8109-22, Jun 1, 2011  Peer-reviewed
    In postnatally developing and adult brains, interneurons of the olfactory bulb (OB) are continuously generated at the subventricular zone of the forebrain. The newborn neuroblasts migrate tangentially to the OB through a well defined pathway, the rostral migratory stream (RMS), where the neuroblasts undergo collective migration termed "chain migration." The cell-intrinsic regulatory mechanism of neuroblast chain migration, however, has not been uncovered. Here we show that mice lacking the actin-binding Akt substrate Girdin (a protein that interacts with Disrupted-In-Schizophrenia 1 to regulate neurogenesis in the dentate gyrus) have profound defects in neuroblast chain migration along the RMS. Analysis of two gene knock-in mice harboring Girdin mutants identified unique amino acid residues in Girdin's C-terminal domain that are responsible for the regulation of neuroblast chain migration but revealed no apparent requirement of Girdin phosphorylation by Akt. Electron microscopic analyses demonstrated the involvement of Girdin in neuroblast cell-cell interactions. These findings suggest that Girdin is an important intrinsic factor that specifically governs neuroblast chain migration along the RMS.
  • Hiroshi Miyake, Kengo Maeda, Naoya Asai, Rei Shibata, Hitoshi Ichimiya, Mayu Isotani-Sakakibara, Yumiko Yamamura, Katsuhiro Kato, Atsushi Enomoto, Masahide Takahashi, Toyoaki Murohara
    Circulation research, 108(10) 1170-9, May 13, 2011  Peer-reviewed
    RATIONALE: It is well established that the migration and proliferation of vascular smooth muscle cells (VSMCs) have major roles in the vascular remodeling process. Our previous study showed that the Akt substrate Girdin, which is expressed in VSMCs and endothelial cells, is essential for postnatal angiogenesis. However, the function of Girdin and its Akt-mediated phosphorylation in VSMCs and their in vivo roles in vascular remodeling remain to be elucidated. OBJECTIVE: We investigated the function of Girdin and its Akt-mediated phosphorylation using cultured VSMCs and animal models of vascular remodeling. METHODS AND RESULTS: The depletion of Girdin by RNA interference disrupted the rearrangement of the actin cytoskeleton in VSMCs, resulting in impaired cell migration. The depletion of Girdin also inhibited VSMC proliferation. Girdin expression was highly upregulated and its serine at position 1416 was phosphorylated in the neointima of carotid arteries after balloon injury in a rat model. The introduction of an adenovirus harboring short hairpin RNA against Girdin attenuated the proliferation of VSMCs and neointima formation without affecting reendothelialization. Furthermore, we found that neointima formation after femoral wire injury was significantly attenuated in Girdin S1416A knock-in mice, in which the Akt phosphorylation site of Girdin was mutated, thus indicating a major role for Girdin phosphorylation in vascular remodeling. CONCLUSIONS: These findings indicate that Girdin and its Akt-mediated phosphorylation have major roles in the migration and proliferation of VSMCs and vascular remodeling, making the Akt/Girdin signaling pathway a potential target for the development of new therapeutics for vascular diseases.
  • Takuya Kato, Atsushi Enomoto, Naoya Asai, Yoshiki Murakumo, Masahide Takahashi
    CANCER RESEARCH, 71, Apr, 2011  
  • Etsushi Matsushita, Naoya Asai, Atsushi Enomoto, Yoshiyuki Kawamoto, Takuya Kato, Shinji Mii, Kengo Maeda, Rei Shibata, Shun Hattori, Minako Hagikura, Ken Takahashi, Masahiro Sokabe, Yoshiki Murakumo, Toyoaki Murohara, Masahide Takahashi
    Molecular biology of the cell, 22(6) 736-47, Mar 15, 2011  Peer-reviewed
    Continued exposure of endothelial cells to mechanical/shear stress elicits the unfolded protein response (UPR), which enhances intracellular homeostasis and protect cells against the accumulation of improperly folded proteins. Cells commit to apoptosis when subjected to continuous and high endoplasmic reticulum (ER) stress unless homeostasis is maintained. It is unknown how endothelial cells differentially regulate the UPR. Here we show that a novel Girdin family protein, Gipie (78 kDa glucose-regulated protein [GRP78]-interacting protein induced by ER stress), is expressed in endothelial cells, where it interacts with GRP78, a master regulator of the UPR. Gipie stabilizes the interaction between GRP78 and the ER stress sensor inositol-requiring protein 1 (IRE1) at the ER, leading to the attenuation of IRE1-induced c-Jun N-terminal kinase (JNK) activation. Gipie expression is induced upon ER stress and suppresses the IRE1-JNK pathway and ER stress-induced apoptosis. Furthermore we found that Gipie expression is up-regulated in the neointima of carotid arteries after balloon injury in a rat model that is known to result in the induction of the UPR. Thus our data indicate that Gipie/GRP78 interaction controls the IRE1-JNK signaling pathway. That interaction appears to protect endothelial cells against ER stress-induced apoptosis in pathological contexts such as atherosclerosis and vascular endothelial dysfunction.
  • Rieko Miyamoto, Mayumi Jijiwa, Masato Asai, Kumi Kawai, Maki Ishida-Takagishi, Shinji Mii, Naoya Asai, Atsushi Enomoto, Yoshiki Murakumo, Akihiko Yoshimura, Masahide Takahashi
    Developmental biology, 349(2) 160-8, Jan 15, 2011  Peer-reviewed
    The glial cell line-derived neurotrophic factor (GDNF)/RET tyrosine kinase signaling pathway plays crucial roles in the development of the enteric nervous system (ENS) and the kidney. Tyrosine 1062 (Y1062) in RET is an autophosphorylation residue that is responsible for the activation of the PI3K/AKT and RAS/MAPK signaling pathways. Mice lacking signaling via Ret Y1062 show renal hypoplasia and hypoganglionosis of the ENS although the phenotype is milder than the Gdnf- or Ret-deficient mice. Sprouty2 (Spry2) was found to be an antagonist for fibroblast growth factor receptor (FGFR) and acts as an inhibitory regulator of ERK activation. Spry2-deficient mice exhibit hearing loss and enteric nerve hyperplasia. In the present study, we generated Spry2-deficient and Ret Y1062F knock-in (tyrosine 1062 is replaced with phenylalanine) double mutant mice to see if abnormalities of the ENS and kidney, caused by loss of signaling via Ret Y1062, are rescued by a deficiency of Spry2. Double mutant mice showed significant recovery of ureteric bud branching and ENS development in the stomach. These results indicate that Spry2 regulates downstream signaling mediated by GDNF/RET signaling complex in vivo.
  • T. Kato, A. Enomoto, W. Liang, N. Asai, Y. Murakumo, M. Takahashi
    MOLECULAR BIOLOGY OF THE CELL, 22, 2011  
  • TAKAHASHI Masahide, ASAI Naoya
    47(4) 308-309, Aug 15, 2010  
  • Nobutaka Ohgami, Michiru Ida-Eto, Takashi Shimotake, Naomi Sakashita, Michihiko Sone, Tsutomu Nakashima, Keiji Tabuchi, Tomofumi Hoshino, Atsuyoshi Shimada, Toyonori Tsuzuki, Masahiko Yamamoto, Gen Sobue, Mayumi Jijiwa, Naoya Asai, Akira Hara, Masahide Takahashi, Masashi Kato
    Proceedings of the National Academy of Sciences of the United States of America, 107(29) 13051-6, Jul 20, 2010  Peer-reviewed
    A significantly increased risk for dominant sensorineural deafness in patients who have Hirschsprung disease (HSCR) caused by endothelin receptor type B and SOX10 has been reported. Despite the fact that c-RET is the most frequent causal gene of HSCR, it has not been determined whether impairments of c-Ret and c-RET cause congenital deafness in mice and humans. Here, we show that impaired phosphorylation of c-Ret at tyrosine 1062 causes HSCR-linked syndromic congenital deafness in c-Ret knockin (KI) mice. The deafness involves neurodegeneration of spiral ganglion neurons (SGNs) with not only impaired phosphorylation of Akt and NF-kappaB but decreased expression of calbindin D28k in inner ears. The congenital deafness involving neurodegeneration of SGNs in c-Ret KI mice was rescued by introducing constitutively activated RET. Taken together with our results for three patients with congenital deafness with c-RET-mediated severe HSCR, our results indicate that c-Ret and c-RET are a deafness-related molecule in mice and humans.
  • Ai Kurotsuchi, Yoshiki Murakumo, Mayumi Jijiwa, Kei Kurokawa, Yasutomo Itoh, Yoshinori Kodama, Takuya Kato, Atsushi Enomoto, Naoya Asai, Hiroko Terasaki, Masahide Takahashi
    Cancer science, 101(5) 1147-55, May, 2010  Peer-reviewed
    Point mutations and structural alterations of the RET tyrosine kinase gene cause multiple endocrine neoplasia type 2 (MEN 2) and papillary thyroid carcinoma, respectively. RET activation by glial cell line-derived neurotrophic factor (GDNF) is essential for the development of the enteric nervous system and the kidney. The signal through RET tyrosine kinase requires several adaptor proteins including the DOK (downstream of kinase) family of proteins. Of the seven members of the DOK protein family, DOK-1, -4, -5, and -6 have been reported to play roles in the GDNF-RET signaling pathway. Although DOK-6 has been shown to bind to RET and promote GDNF-induced neurite outgrowth in mouse Neuro2A cells, DOK-6 function in human cells remains unclear. In the present study, we investigated the role of DOK-6 in GDNF-RET signaling in human cells including neuroblastoma cells. DOK-6 was constitutively localized to the plasma membrane via its pleckstrin homology (PH) domain, and was phosphorylated following RET activation via a MEN2A mutation or GDNF stimulation. However, DOK-6 could not significantly affect downstream signaling and neurite outgrowth in human neuroblastoma cells. The binding affinity of the DOK-6 phosphotyrosine-binding (PTB) domain to RET was much lower than that of the DOK-1, DOK-4, and SHC PTB domains to RET. These findings indicate that DOK-6 is involved in RET signaling with less influence when compared with DOK-1, DOK-4, and SHC.
  • Liang Weng, Atsushi Enomoto, Maki Ishida-Takagishi, Naoya Asai, Masahide Takahashi
    Cancer science, 101(4) 836-42, Apr, 2010  Peer-reviewed
    Cell migration is a fundamental aspect of a multitude of physiological and pathological processes, including embryonic development, inflammation, angiogenesis, and cancer progression. A variety of proteins are essential for cell migration, but context-specific signaling pathways and promigratory proteins must now be identified for our understanding of cancer biology to continue to advance. In this review, we focus on the emerging roles of Girdin (also designated KIAA1212, APE, GIV, and HkRP1), a novel component of the phosphatidylinositol 3-kinase (PI3-K)/Akt signaling pathway that is a core-signaling transduction pathway in cancer progression. Girdin is expressed in some types of cancer cells and immature endothelial cells, and is therefore at the crossroads of multiple intracellular processes, including reorganization of the actin cytoskeleton, endocytosis, and modulation of Akt activity, which ultimately lead to cancer invasion and angiogenesis. It also acts as a nonreceptor guanine nucleotide exchange factor (GEF) for Galphai proteins. A significant observation is that Girdin, although vital for cancer progression and postnatal vascular remodelling, is dispensable for cell migratory events during embryonic development. These findings suggest that Girdin and its interacting proteins are potential pharmaceutical targets for cancer therapies and pathological anigiogenesis, including tumor angiogenesis.
  • Toyoaki Murohara, Kengo Maeda
    JOURNAL OF PHARMACOLOGICAL SCIENCES, 112(3) 40P-40P, 2010  Peer-reviewed
    The serine/threonine protein kinase Akt is involved in a variety of cellular processes including cell proliferation, survival, metabolism and gene expression. It is essential in vascular endothelial growth factor (VEGF)-mediated angiogenesis; however, it is not known how Akt regulates the migration of endothelial cells, a crucial process for vessel sprouting, branching and the formation of networks during angiogenesis. Here we report that Akt-mediated phosphorylation of Girdin, an actin-binding protein, promotes VEGF-dependent migration of endothelial cells and tube formation by these cells. We found that exogenously delivered adenovirus harbouring Girdin short interfering RNA in Matrigel embedded in mice, markedly inhibited VEGF-mediated angiogenesis. Targeted disruption of the Girdin gene in mice impaired vessel remodelling in the retina and angiogenesis from aortic rings, whereas Girdin was dispensable for embryonic vasculogenesis. These findings demonstrate that the Akt/Girdin signalling pathway is essential in VEGF-mediated postneonatal angiogenesis.
  • Benson C Lu, Cristina Cebrian, Xuan Chi, Satu Kuure, Richard Kuo, Carlton M Bates, Silvia Arber, John Hassell, Lesley MacNeil, Masato Hoshi, Sanjay Jain, Naoya Asai, Masahide Takahashi, Kai M Schmidt-Ott, Jonathan Barasch, Vivette D'Agati, Frank Costantini
    Nature genetics, 41(12) 1295-302, Dec, 2009  Peer-reviewed
    Glial cell line-derived neurotrophic factor signaling through the Ret receptor tyrosine kinase is crucial for ureteric bud branching morphogenesis during kidney development, yet few of the downstream genes are known. Here we show that the ETS transcription factors Etv4 and Etv5 are positively regulated by Ret signaling in the ureteric bud tips. Mice lacking both Etv4 alleles and one Etv5 allele show either renal agenesis or severe hypodysplasia, whereas kidney development fails completely in double homozygotes. We identified several genes whose expression in the ureteric bud depends on Etv4 and Etv5, including Cxcr4, Myb, Met and Mmp14. Thus, Etv4 and Etv5 are key components of a gene network downstream of Ret that promotes and controls renal branching morphogenesis.
  • Hirohisa Tsukamoto, Takuya Kato, Atsushi Enomoto, Nobuhisa Nakamura, Yohei Shimono, Mayumi Jijiwa, Naoya Asai, Yoshiki Murakumo, Kiyosumi Shibata, Fumitaka Kikkawa, Masahide Takahashi
    Cancer science, 100(10) 1895-901, Oct, 2009  Peer-reviewed
    Ret finger protein (RFP) is a nuclear protein with transcriptional repressive activity that is highly expressed in a variety of human and rodent tumor cell lines. We examined the expression of RFP in human endometrial cancer and assessed its clinical significance. Formalin-fixed, paraffin-embedded sections from endometrial cancer tissues were immunostained with the RFP antibody, and the staining intensity was evaluated. The clinicopathological factors examined were age, International Federation of Gynecology and Obstetrics stage, tumor grade, myometrial invasion, and pelvic lymph node metastasis. Overall survival (OS) and progression-free survival (PFS) were evaluated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis. Of the 119 cancer tissues, 57 (47.9%) cases were positive for RFP immunoreactivity. RFP expression was not associated with any of the clinicopathological parameters examined. However, positive RFP expression significantly predicted poorer OS and PFS compared with negative expression (OS, P = 0.0011; PFS, P < 0.0001). In the multivariate analyses, positive RFP expression was an independent prognostic factor for survival in this study. RFP knockdown significantly impaired cancer cell migration and invasion in vitro with concomitant decreases of integrins beta1 and alpha2. Positive RFP expression is a predictive marker for an unfavorable clinical outcome in patients with endometrial cancer.
  • Atsushi Enomoto, Naoya Asai, Takashi Namba, Yun Wang, Takuya Kato, Motoki Tanaka, Hitoshi Tatsumi, Shinichiro Taya, Daisuke Tsuboi, Keisuke Kuroda, Naoko Kaneko, Kazunobu Sawamoto, Rieko Miyamoto, Mayumi Jijiwa, Yoshiki Murakumo, Masahiro Sokabe, Tatsunori Seki, Kozo Kaibuchi, Masahide Takahashi
    Neuron, 63(6) 774-87, Sep 24, 2009  Peer-reviewed
    Disrupted-In-Schizophrenia 1 (DISC1), a susceptibility gene for major psychiatric disorders, regulates neuronal migration and differentiation during mammalian brain development. Although roles for DISC1 in postnatal neurogenesis in the dentate gyrus (DG) have recently emerged, it is not known how DISC1 and its interacting proteins govern the migration, positioning, and differentiation of dentate granule cells (DGCs). Here, we report that DISC1 interacts with the actin-binding protein girdin to regulate axonal development. DGCs in girdin-deficient neonatal mice exhibit deficits in axonal sprouting in the cornu ammonis 3 region of the hippocampus. Girdin deficiency, RNA interference-mediated knockdown, and inhibition of the DISC1/girdin interaction lead to overextended migration and mispositioning of the DGCs resulting in profound cytoarchitectural disorganization of the DG. These findings identify girdin as an intrinsic factor in postnatal development of the DG and provide insights into the critical role of the DISC1/girdin interaction in postnatal neurogenesis in the DG.
  • Xuan Chi, Odyssé Michos, Reena Shakya, Paul Riccio, Hideki Enomoto, Jonathan D Licht, Naoya Asai, Masahide Takahashi, Nobutaka Ohgami, Masashi Kato, Cathy Mendelsohn, Frank Costantini
    Developmental cell, 17(2) 199-209, Aug, 2009  Peer-reviewed
    While the genetic control of renal branching morphogenesis has been extensively described, the cellular basis of this process remains obscure. GDNF/RET signaling is required for ureter and kidney development, and cells lacking Ret are excluded from the tips of the branching ureteric bud in chimeric kidneys. Here, we find that this exclusion results from earlier Ret-dependent cell rearrangements in the caudal Wolffian duct, which generate a specialized epithelial domain that later emerges as the tip of the primary ureteric bud. By juxtaposing cells with elevated or reduced RET activity, we find that Wolffian duct cells compete, based on RET signaling levels, to contribute to this domain. At the same time, the caudal Wolffian duct transiently converts from a simple to a pseudostratified epithelium, a process that does not require Ret. Thus, both Ret-dependent cell movements and Ret-independent changes in the Wolffian duct epithelium contribute to ureteric bud formation.
  • Takuya Kato, Yohei Shimono, Masaki Hasegawa, Mayumi Jijiwa, Atsushi Enomoto, Naoya Asai, Yoshiki Murakumo, Masahide Takahashi
    Cancer research, 69(8) 3597-604, Apr 15, 2009  Peer-reviewed
    Histone deacetylases (HDAC) are involved in carcinogenesis through their regulation of cell proliferation, differentiation, and survival. The inhibitors of HDAC exhibit profound synergistic effects in cancer treatment when combined with other anticancer drugs. However, the molecular mechanisms underlying this synergy are not fully understood. Here, we show that HDAC1 increases the resistance of cancer cells to oxidative stress by negatively regulating the expression of thioredoxin binding protein 2 (TBP-2). We found that the recruitment of HDAC1 to the TBP-2 promoter is mediated by a protein complex consisting of RET finger protein (RFP; also called TRIM27) and the trimeric transcription factor NF-Y. Accordingly, RNA interference-mediated depletion of RFP led to the disruption of the protein complex and a marked increase in the sensitivity of cancer cells to cisplatin, a potent inducer of oxidative stress. Furthermore, high levels of RFP expression correlated with down-regulation of TBP-2 in human colon cancers and were associated with poor clinical outcome. These findings reveal the diverse cancer-promoting activities of HDAC1 and identify RFP as a key regulator that provides cancer cells with resistance to anticancer drugs.

Books and Other Publications

 1

Professional Memberships

 3

Research Projects

 22
More
To the list screen