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935 results on '"Hirano, Toshio"'

55. Zebrafish Dkk1 Functions in Forebrain Specification and Axial Mesendoderm Formation

Author

Hasimoto, Hisashi, Itoh, Motoyuki, Yamanaka, Yojiro, Yamashita, Susumu, Shimizu, Takashi, Solnica-Krezel, Lilianna, Hibi, Masahiko, and Hirano, Toshio

Subjects
Developmental biology -- Research, Embryology -- Research, Biological sciences
Abstract

We identified a zebrafish homologue of Dickkopf-1 (Dkk1), which was previously identified in Xenopus as a Wnt inhibitor with potent head-inducing activity. Zebrafish dkk1 is expressed in the dorsal marginal blastoderm and also in the dorsal yolk syncytial layer after mid-blastula transition. At later blastula stages, the expression expands to the entire blastoderm margin. During gastrulation, dkk1-expressing cells are confined to the embryonic shield and later to the anterior axial mesendoderm, prospective prechordal plate. Embryos, in which dkk1 was ectopically expressed, exhibited enlarged forebrain, eyes, and axial rnesendoderm such as prechordal plate and notochord, dkk1 expression in the dorso.anterior mesendoderm during gastrulation was prominently reduced in zebrafish mutants bozozok (boz), squint (sqt), and one-eyed pinhead (oep), which all display abnormalities in the formation and function of the Spemann organizer and axial mesendoderm, dkk1 expression was normal in these embryos during the blastula period, indicating that zygotic functions of these genes are required for maintenance but not establishment of dkk1 expression. Overexpression of dkk1 suppressed defects in the development of forebrain, eyes, and notochord in boz mutants. Overexpression of dkk1 promoted anterior neuroectoderm development in the embryos injected with antivin RNA, which lack most of the mesoderm and endoderm, suggesting that Dkk1 can affect regionalization of neuroectoderm independently of dorso-anterior mesendoderm. These data indicate that Dkk1, expressed in dorsal mesendoderm, functions in the formation of both the anterior nervous system and the axial mesendoderm in zebrafish.

Published
2000

72. A novel homeobox gene, dharma, can induce the organizer in a non-cell-autonomous manner

Author

Yamanaka, Yojiro, Mizuno, Toshiro, Sasai, Yoshiki, Kishi, Masashi, Takeda, Hiroyuki, Kim, Cheol-Hee, Hibi, Masahiko, and Hirano, Toshio

Subjects
Fishes -- Genetic aspects, Vertebrates -- Genetic aspects, Cell interaction -- Research, Cell differentiation -- Genetic aspects, Embryology -- Genetic aspects, Homeobox genes -- Research, Biological sciences
Abstract

Formation of Spemann organizer is a very significant stage in dorsoventral axis determination of vertebrate development. A novel zebrafish homeobox gene, dharma, has been isolated. It can induce the organizer ectopically. For the first time a zygotic gene implicated in formation of an organizer-inducing center has been identified.

Published
1998

74. Origin of the mesodermal tissues of the juvenile

Author

Hirano, Toshio and Nishida, Hiroki

Subjects
Ascidiacea -- Research, Cell lines -- Research, Metamorphosis -- Research, Mesoderm -- Research, Biological sciences
Abstract

Cell lineages during ascidian embryogenesis are invariant. In a previous study, the developmental fate of each blastomere during embryogenesis of the ascidian Halocynthia roretzi was analyzed in detail by intracellular injection of a tracer molecule, horseradish peroxidase (Nishida, H., Dev. Biol. 121, 526-541, 1987). In the present study, the developmental fates of various larval mesodermal tissues after metamorphosis in H. roretzi were traced by labeling each precursor blastomere of larval tissues. Mesenchyme cells of larvae gave rise to tunic cells of juveniles. Trunk ventral cells gave rise to body-wall (atrial siphon and latitudinal mantle) muscle, heart, and pericardium of juvenile. Trunk lateral cells gave rise to blood (coelomic) cells as well as body-wall (oral siphon and longitudinal mantle) muscle. Larval muscle and notochord cells did not contribute to juvenile tissues. It was revealed that it is predictable to which juvenile tissue a blastomere of the 110-cell embryo will give rise. Therefore, in ascidian development, developmental fates after metamorphosis were almost invariant with regard to cell type of descendants. Key Words: cell lineages; ascidian development; metamorphosis; HRP injection; mesoderm differentiation.

Published
1997

87. Interleukin-6 Receptor and Signals

Author

Taga, Tetsuya, primary, Hibi, Masahiko, additional, Murakami, Masaaki, additional, Saito, Mikiyoshi, additional, Yawata, Hideo, additional, Narazaki, Masashi, additional, Hirata, Yuuichi, additional, Sugita, Takahisa, additional, Yasukawa, Kiyoshi, additional, Hirano, Toshio, additional, and Kishimoto, Tadamitsu, additional

Published
1992
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98. IL-6 in inflammation, autoimmunity and cancer.

Author

Hirano, Toshio

Subjects
*TUMOR necrosis factors, *INTERLEUKIN-6, *NF-kappa B, *AUTOIMMUNITY, *IMMUNOLOGICAL tolerance
Abstract

IL-6 is involved both in immune responses and in inflammation, hematopoiesis, bone metabolism and embryonic development. IL-6 plays roles in chronic inflammation (closely related to chronic inflammatory diseases, autoimmune diseases and cancer) and even in the cytokine storm of corona virus disease 2019 (COVID-19). Acute inflammation during the immune response and wound healing is a well-controlled response, whereas chronic inflammation and the cytokine storm are uncontrolled inflammatory responses. Non-immune and immune cells, cytokines such as IL-1β, IL-6 and tumor necrosis factor alpha (TNFα) and transcription factors nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) play central roles in inflammation. Synergistic interactions between NF-κB and STAT3 induce the hyper-activation of NF-κB followed by the production of various inflammatory cytokines. Because IL-6 is an NF-κB target, simultaneous activation of NF-κB and STAT3 in non-immune cells triggers a positive feedback loop of NF-κB activation by the IL-6–STAT3 axis. This positive feedback loop is called the IL-6 amplifier (IL-6 Amp) and is a key player in the local initiation model, which states that local initiators, such as senescence, obesity, stressors, infection, injury and smoking, trigger diseases by promoting interactions between non-immune cells and immune cells. This model counters dogma that holds that autoimmunity and oncogenesis are triggered by the breakdown of tissue-specific immune tolerance and oncogenic mutations, respectively. The IL-6 Amp is activated by a variety of local initiators, demonstrating that the IL-6–STAT3 axis is a critical target for treating diseases. [ABSTRACT FROM AUTHOR]

Published
2021
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