PhysiologyI

亀山 俊樹

Toshiki Kameyama

基本情報

所属
藤田医科大学 医学部 生理学 I 准教授
学位
博士(理学)(名古屋大学)

研究者番号
60298544
ORCID ID
 https://orcid.org/0000-0002-7348-7572
J-GLOBAL ID
200901005394038415
researchmap会員ID
1000226784

外部リンク

神経細胞の分化機構を研究しています。

 


学歴

 2

委員歴

 1

論文

 28
  • Miho Kawata, Yu Kodani, Mahito Ohkuma, Ei-Ichi Miyachi, Yoko S Kaneko, Akira Nakashima, Hidetaka Suga, Toshiki Kameyama, Kanako Saito, Hiroshi Nagasaki
    PloS one 17(11) e0276694 2022年11月  査読有り
    The hypothalamus is comprised of heterogenous cell populations and includes highly complex neural circuits that regulate the autonomic nerve system. Its dysfunction therefore results in severe endocrine disorders. Although recent experiments have been conducted for in vitro organogenesis of hypothalamic neurons from embryonic stem (ES) or induced pluripotent stem (iPS) cells, whether these stem cell-derived hypothalamic neurons can be useful for regenerative medicine remains unclear. We therefore performed orthotopic transplantation of mouse ES cell (mESC)-derived hypothalamic neurons into adult mouse brains. We generated electrophysiologically functional hypothalamic neurons from mESCs and transplanted them into the supraoptic nucleus of mice. Grafts extended their axons along hypothalamic nerve bundles in host brain, and some of them even projected into the posterior pituitary (PPit), which consists of distal axons of the magnocellular neurons located in hypothalamic supraoptic and paraventricular nuclei. The axonal projections to the PPit were not observed when the mESC-derived hypothalamic neurons were ectopically transplanted into the substantia nigra reticular part. These findings suggest that our stem cell-based orthotopic transplantation approach might contribute to the establishment of regenerative medicine for hypothalamic and pituitary disorders.
  • Yu Kodani, Miho Kawata, Hidetaka Suga, Takatoshi Kasai, Chikafumi Ozone, Mayu Sakakibara, Atsushi Kuwahara, Shiori Taga, Hiroshi Arima, Toshiki Kameyama, Kanako Saito, Akira Nakashima, Hiroshi Nagasaki
    Frontiers in Endocrinology 13 941166-941166 2022年7月12日  査読有り
    Human stem cell-derived organoid culture enables the in vitro analysis of the cellular function in three-dimensional aggregates mimicking native organs, and also provides a valuable source of specific cell types in the human body. We previously established organoid models of the hypothalamic-pituitary (HP) complex using human pluripotent stem cells. Although the models are suitable for investigating developmental and functional HP interactions, we consider that isolated pituitary cells are also useful for basic and translational research on the pituitary gland, such as stem cell biology and regenerative medicine. To develop a method for the purification of pituitary cells in HP organoids, we performed surface marker profiling of organoid cells derived from human induced pluripotent stem cells (iPSCs). Screening of 332 human cell surface markers and a subsequent immunohistochemical analysis identified epithelial cell adhesion molecule (EpCAM) as a surface marker of anterior pituitary cells, as well as their ectodermal precursors. EpCAM was not expressed on hypothalamic lineages; thus, anterior pituitary cells were successfully enriched by magnetic separation of EpCAM+ cells from iPSC-derived HP organoids. The enriched pituitary population contained functional corticotrophs and their progenitors; the former responded normally to a corticotropin-releasing hormone stimulus. Our findings would extend the applicability of organoid culture as a novel source of human anterior pituitary cells, including stem/progenitor cells and their endocrine descendants.
  • Yu Kodani, Miho Kawata, Hidetaka Suga, Yoko S Kaneko, Akira Nakashima, Toshiki Kameyama, Kanako Saito, Hiroshi Nagasaki
    eNeuro 2022年4月18日  査読有り
    Hypothalamic melanin-concentrating hormone (MCH) neurons are important regulators of multiple physiological processes, such as sleep, feeding, and memory. Despite the increasing interest in their neuronal functions, the molecular mechanism underlying MCH neuron development remains poorly understood. We report that a three-dimensional culture of mouse embryonic stem cells (mESCs) can generate hypothalamic-like tissues containing MCH-positive neurons, which reproduce morphologic maturation, neuronal connectivity, and neuropeptide/neurotransmitter phenotype of native MCH neurons. Using this in vitro system, we demonstrate that Hedgehog (Hh) signaling serves to produce major neurochemical subtypes of MCH neurons characterized by the presence or absence of cocaine- and amphetamine-regulated transcript (CART). Without exogenous Hh signals, mESCs initially differentiated into dorsal hypothalamic/prethalamic progenitors and finally into MCH+CART+ neurons through a specific intermediate progenitor state. Conversely, activation of the Hh pathway specified ventral hypothalamic progenitors that generate both MCH+CART- and MCH+CART+ neurons. These results suggest that in vivo MCH neurons may originate from multiple cell lineages that arise through early dorsoventral patterning of the hypothalamus. Additionally, we found that Hh signaling supports the differentiation of mESCs into orexin/hypocretin neurons, a well-defined cell group intermingled with MCH neurons in the lateral hypothalamic area (LHA). The present study highlights and improves the utility of mESC culture in the analysis of the developmental programs of specific hypothalamic cell types.Significance StatementA growing body of literature has revealed the importance of hypothalamic melanin-concentrating hormone (MCH) neurons in energy homeostasis and the cognitive function, but their developmental biology remains relatively unknown. To establish a new approach for addressing this issue, we tested the ability of an in vitro differentiation system of mouse embryonic stem cells (mESCs) to recapitulate the development of MCH neurons. The mESC culture robustly generated MCH-positive neurons resembling native neurons in several aspects and provided evidence that Hedgehog (Hh) signaling is a key factor to produce neurochemical subtypes of MCH neurons. Our results demonstrate the suitability of mESC culture as a platform to study the molecular mechanisms underlying the development of MCH neurons and possibly of other hypothalamic cell types.
  • Huey-Huey Chua, Toshiki Kameyama, Akila Mayeda, Te-Huei Yeh
    International journal of molecular sciences 23(5) 2022年2月24日  査読有り
    Tumor viruses gain control of cellular functions when they infect and transform host cells. Alternative splicing is one of the cellular processes exploited by tumor viruses to benefit viral replication and support oncogenesis. Epstein-Barr virus (EBV) participates in a number of cancers, as reported mostly in nasopharyngeal carcinoma (NPC) and Burkitt lymphoma (BL). Using RT-nested-PCR and Northern blot analysis in NPC and BL cells, here we demonstrate that EBV promotes specific alternative splicing of TSG101 pre-mRNA, which generates the TSG101∆154-1054 variant though the agency of its viral proteins, such as EBNA-1, Zta and Rta. The level of TSG101∆154-1054 is particularly enhanced upon EBV entry into the lytic cycle, increasing protein stability of TSG101 and causing the cumulative synthesis of EBV late lytic proteins, such as VCA and gp350/220. TSG101∆154-1054-mediated production of VCA and gp350/220 is blocked by the overexpression of a translational mutant of TSG101∆154-1054 or by the depletion of full-length TSG101, which is consistent with the known role of the TSG101∆154-1054 protein in stabilizing the TSG101 protein. NPC patients whose tumor tissues express TSG101∆154-1054 have high serum levels of anti-VCA antibodies and high levels of viral DNA in their tumors. Our findings highlight the functional importance of TSG101∆154-1054 in allowing full completion of the EBV lytic cycle to produce viral particles. We propose that targeting EBV-induced TSG101 alternative splicing has broad potential as a therapeutic to treat EBV-associated malignancies.
  • Otani, Yuta, Fujita, Ken-ichi, Kameyama, Toshiki, Mayeda, Akila
    International Journal of Molecular Sciences 22(12) 6519 2021年6月  査読有り責任著者

MISC

 26

書籍等出版物

 2

講演・口頭発表等

 15

担当経験のある科目(授業)

 15
  • 2024年4月 - 現在
    病態生理学特論  (藤田医科大学大学院保健学研究科保健学専攻看護学領域 急性期・周術期分野)
  • 2024年4月 - 現在
    人体機能学概論  (藤田医科大学大学院医学研究科博士前期課程)
  • 2022年4月 - 現在
    遺伝学  (中京学院大学看護学部)
  • 2022年4月 - 現在
    医学教育入門  (藤田医科大学医学部医学科)
  • 2021年4月 - 現在
    Human Biology  (藤田医科大学医学部医学科)

共同研究・競争的資金等の研究課題

 18

学術貢献活動

 3

メディア報道

 1

その他

 3