Full Text Journal Articles by
Author Takuya Imamura


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SoxE group transcription factor Sox8 promotes astrocytic differentiation of neural stem/precursor cells downstream of Nfia.

Jun Takouda, Sayako Katada, Takuya Imamura, Tsukasa Sanosaka, Kinichi Nakashima,

The brain consists of three major cell types: neurons and two glial cell types (astrocytes and oligodendrocytes). Although they are generated from common multipotent neural stem/precursor cells (NS/PCs), embryonic NS/PCs cannot generate all of the cell types at the beginning of brain development. NS/PCs first undergo extensive self-renewal to expand ... Read more >>

Pharmacol Res Perspect (Pharmacology research & perspectives)
[2021, 9(6):e00749]

Cited: 1 time

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Neural stem/precursor cells dynamically change their epigenetic landscape to differentially respond to BMP signaling for fate switching during brain development.

Sayako Katada, Jun Takouda, Takumi Nakagawa, Mizuki Honda, Katsuhide Igarashi, Takuya Imamura, Yasuyuki Ohkawa, Shoko Sato, Hitoshi Kurumizaka, Kinichi Nakashima,

During neocortical development, tight regulation of neurogenesis-to-astrogenesis switching of neural precursor cells (NPCs) is critical to generate a balanced number of each neural cell type for proper brain functions. Accumulating evidence indicates that a complex array of epigenetic modifications and the availability of extracellular factors control the timing of neuronal ... Read more >>

Genes Dev (Genes & development)
[2021, 35(21-22):1431-1444]

Cited: 0 times

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Neuronal activation modulates enhancer activity of genes for excitatory synaptogenesis through de novo DNA methylation.

Tomonori Kameda, Hideyuki Nakashima, Takumi Takizawa, Fumihito Miura, Takashi Ito, Kinichi Nakashima, Takuya Imamura,

Post-mitotic neurons do exhibit DNA methylation changes, contrary to the longstanding belief that the epigenetic pattern in terminally differentiated cells is essentially unchanged. While the mechanism and physiological significance of DNA demethylation in neurons have been extensively elucidated, the occurrence of de novo DNA methylation and its impacts have been ... Read more >>

J Reprod Dev (The Journal of reproduction and development)
[2021, :]

Cited: 0 times

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The evolutionary acquisition and mode of functions of promoter-associated non-coding RNAs (pancRNAs) for mammalian development.

Boyang An, Tomonori Kameda, Takuya Imamura,

Increasing evidence has shown that many long non-coding RNAs (lncRNAs) are involved in gene regulation in a variety of ways such as transcriptional, post-transcriptional and epigenetic regulation. Promoter-associated non-coding RNAs (pancRNAs), which are categorized into the most abundant single-copy lncRNA biotype, play vital regulatory roles in finely tuning cellular specification ... Read more >>

Essays Biochem (Essays in biochemistry)
[2021, 65(4):697-708]

Cited: 0 times

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Generation of ovarian follicles from mouse pluripotent stem cells.

Takashi Yoshino, Takahiro Suzuki, Go Nagamatsu, Haruka Yabukami, Mika Ikegaya, Mami Kishima, Haruka Kita, Takuya Imamura, Kinichi Nakashima, Ryuichi Nishinakamura, Makoto Tachibana, Miki Inoue, Yuichi Shima, Ken-Ichirou Morohashi, Katsuhiko Hayashi,

Oocytes mature in a specialized fluid-filled sac, the ovarian follicle, which provides signals needed for meiosis and germ cell growth. Methods have been developed to generate functional oocytes from pluripotent stem cell-derived primordial germ cell-like cells (PGCLCs) when placed in culture with embryonic ovarian somatic cells. In this study, we ... Read more >>

Science (Science (New York, N.Y.))
[2021, 373(6552):]

Cited: 1 time

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MeCP2 controls neural stem cell fate specification through miR-199a-mediated inhibition of BMP-Smad signaling.

Hideyuki Nakashima, Keita Tsujimura, Koichiro Irie, Takuya Imamura, Cleber A Trujillo, Masataka Ishizu, Masahiro Uesaka, Miao Pan, Hirofumi Noguchi, Kanako Okada, Kei Aoyagi, Tomoko Andoh-Noda, Hideyuki Okano, Alysson R Muotri, Kinichi Nakashima,

Rett syndrome (RTT) is a severe neurological disorder, with impaired brain development caused by mutations in MECP2; however, the underlying mechanism remains elusive. We know from previous work that MeCP2 facilitates the processing of a specific microRNA, miR-199a, by associating with the Drosha complex to regulate neuronal functions. Here, we ... Read more >>

Cell Rep (Cell reports)
[2021, 35(7):109124]

Cited: 1 time

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Inducible Kiss1 knockdown in the hypothalamic arcuate nucleus suppressed pulsatile secretion of luteinizing hormone in male mice.

Shiori Minabe, Sho Nakamura, Eri Fukushima, Marimo Sato, Kana Ikegami, Teppei Goto, Makoto Sanbo, Masumi Hirabayashi, Junko Tomikawa, Takuya Imamura, Naoko Inoue, Yoshihisa Uenoyama, Hiroko Tsukamura, Kei-Ichiro Maeda, Fuko Matsuda,

Accumulating evidence suggests that kisspeptin-GPR54 signaling is indispensable for gonadotropin-releasing hormone (GnRH)/gonadotropin secretion and consequent reproductive functions in mammals. Conventional Kiss1 knockout (KO) mice and rats are reported to be infertile. To date, however, no study has investigated the effect of inducible central Kiss1 KO/knockdown on pulsatile gonadotropin release in ... Read more >>

J Reprod Dev (The Journal of reproduction and development)
[2020, 66(4):369-375]

Cited: 2 times

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Conditional kisspeptin neuron-specific Kiss1 knockout with newly generated Kiss1-floxed and Kiss1-Cre mice replicates a hypogonadal phenotype of global Kiss1 knockout mice.

Kana Ikegami, Teppei Goto, Sho Nakamura, Youki Watanabe, Arisa Sugimoto, Sutisa Majarune, Kei Horihata, Mayuko Nagae, Junko Tomikawa, Takuya Imamura, Makoto Sanbo, Masumi Hirabayashi, Naoko Inoue, Kei-Ichiro Maeda, Hiroko Tsukamura, Yoshihisa Uenoyama,

The present study aimed to evaluate whether novel conditional kisspeptin neuron-specific Kiss1 knockout (KO) mice utilizing the Cre-loxP system could recapitulate the infertility of global Kiss1 KO models, thereby providing further evidence for the fundamental role of hypothalamic kisspeptin neurons in regulating mammalian reproduction. We generated Kiss1-floxed mice and hypothalamic ... Read more >>

J Reprod Dev (The Journal of reproduction and development)
[2020, 66(4):359-367]

Cited: 3 times

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Modeling of early neural development in vitro by direct neurosphere formation culture of chimpanzee induced pluripotent stem cells.

Ryunosuke Kitajima, Risako Nakai, Takuya Imamura, Tomonori Kameda, Daiki Kozuka, Hirohisa Hirai, Haruka Ito, Hiroo Imai, Masanori Imamura,

Evolutionary developmental biology of our closest living relative, the chimpanzee (Pan troglodytes), is essential for understanding the origin of human traits. However, it is difficult to access developmental events in the chimpanzee in vivo because of technical and ethical restrictions. Induced pluripotent stem cells (iPSCs) offer an alternative in vitro ... Read more >>

Stem Cell Res (Stem cell research)
[2020, 44:101749]

Cited: 0 times

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Pioneer Factor NeuroD1 Rearranges Transcriptional and Epigenetic Profiles to Execute Microglia-Neuron Conversion.

Taito Matsuda, Takashi Irie, Shutaro Katsurabayashi, Yoshinori Hayashi, Tatsuya Nagai, Nobuhiko Hamazaki, Aliya Mari D Adefuin, Fumihito Miura, Takashi Ito, Hiroshi Kimura, Katsuhiko Shirahige, Tadayuki Takeda, Katsunori Iwasaki, Takuya Imamura, Kinichi Nakashima,

Minimal sets of transcription factors can directly reprogram somatic cells into neurons. However, epigenetic remodeling during neuronal reprogramming has not been well reconciled with transcriptional regulation. Here we show that NeuroD1 achieves direct neuronal conversion from mouse microglia both in vitro and in vivo. Exogenous NeuroD1 initially occupies closed chromatin regions associated ... Read more >>

Neuron (Neuron)
[2019, 101(3):472-485.e7]

Cited: 34 times

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DNA Methylome Analysis Identifies Transcription Factor-Based Epigenomic Signatures of Multilineage Competence in Neural Stem/Progenitor Cells.

Tsukasa Sanosaka, Takuya Imamura, Nobuhiko Hamazaki, MuhChyi Chai, Katsuhide Igarashi, Maky Ideta-Otsuka, Fumihito Miura, Takashi Ito, Nobuyuki Fujii, Kazuho Ikeo, Kinichi Nakashima,

Regulation of the epigenome during in vivo specification of brain stem cells is still poorly understood. Here, we report DNA methylome analyses of directly sampled cortical neural stem and progenitor cells (NS/PCs) at different development stages, as well as those of terminally differentiated cortical neurons, astrocytes, and oligodendrocytes. We found that sequential specification ... Read more >>

Cell Rep (Cell reports)
[2017, 20(12):2992-3003]

Cited: 13 times

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Evolutionary acquisition of promoter-associated non-coding RNA (pancRNA) repertoires diversifies species-dependent gene activation mechanisms in mammals.

Masahiro Uesaka, Kiyokazu Agata, Takao Oishi, Kinichi Nakashima, Takuya Imamura,

<h4>Background</h4>Recent transcriptome analyses have shown that long non-coding RNAs (ncRNAs) play extensive roles in transcriptional regulation. In particular, we have reported that promoter-associated ncRNAs (pancRNAs) activate the partner gene expression via local epigenetic changes.<h4>Results</h4>Here, we identify thousands of genes under pancRNA-mediated transcriptional activation in five mammalian species in common. In ... Read more >>

BMC Genomics (BMC genomics)
[2017, 18(1):285]

Cited: 5 times

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Epigenetic regulation of neural stem cell differentiation towards spinal cord regeneration.

Tomonori Kameda, Takuya Imamura, Kinichi Nakashima,

Severe spinal cord injury (SCI) leads to almost complete neural cell loss at the injured site, causing the irreversible disruption of neuronal circuits. The transplantation of neural stem or precursor cells (NS/PCs) has been regarded as potentially effective for SCI treatment because NS/PCs can compensate for the injured sites by ... Read more >>

Cell Tissue Res (Cell and tissue research)
[2018, 371(1):189-199]

Cited: 8 times

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Detection of Bidirectional Promoter-Derived lncRNAs from Small-Scale Samples Using Pre-Amplification-Free Directional RNA-seq Method.

Nobuhiko Hamazaki, Kinichi Nakashima, Katsuhiko Hayashi, Takuya Imamura,

Development of high-throughput sequencing technologies has uncovered the immensity of the long noncoding RNA (lncRNA) world. Divergently transcribed lncRNAs from bidirectional gene promoters, called promoter-associated noncoding RNAs (pancRNAs), account for ~20% of the total number of lncRNAs, and this major fraction is involved in many biological processes, such as development ... Read more >>

Methods Mol Biol (Methods in molecular biology (Clifton, N.J.))
[2017, 1605:83-103]

Cited: 3 times

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Manipulation of Promoter-Associated Noncoding RNAs in Mouse Early Embryos for Controlling Sequence-Specific Epigenetic Status.

Nobuhiko Hamazaki, Kinichi Nakashima, Takuya Imamura,

In mammals, transcription in the zygote begins after fertilization. This transcriptional wave is called zygotic gene activation (ZGA). During ZGA, epigenetic modifications, such as DNA methylation and histone modifications, are dynamically and drastically reconstructed in a sequence-specific manner. However, how such orchestrated gene upregulation is regulated remains unknown. Recently, using ... Read more >>

Methods Mol Biol (Methods in molecular biology (Clifton, N.J.))
[2017, 1543:271-282]

Cited: 2 times

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Reconstitution in vitro of the entire cycle of the mouse female germ line.

Orie Hikabe, Nobuhiko Hamazaki, Go Nagamatsu, Yayoi Obata, Yuji Hirao, Norio Hamada, So Shimamoto, Takuya Imamura, Kinichi Nakashima, Mitinori Saitou, Katsuhiko Hayashi,

The female germ line undergoes a unique sequence of differentiation processes that confers totipotency to the egg. The reconstitution of these events in vitro using pluripotent stem cells is a key achievement in reproductive biology and regenerative medicine. Here we report successful reconstitution in vitro of the entire process of ... Read more >>

Nature (Nature)
[2016, 539(7628):299-303]

Cited: 159 times

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Bidirectional promoters link cAMP signaling with irreversible differentiation through promoter-associated non-coding RNA (pancRNA) expression in PC12 cells.

Naoki Yamamoto, Kiyokazu Agata, Kinichi Nakashima, Takuya Imamura,

Bidirectional promoters are the major source of gene activation-associated noncoding RNA (ncRNA). PC12 cells offer an interesting model for understanding the mechanism underlying bidirectional promoter-mediated cell cycle control. Nerve growth factor (NGF)-stimulated PC12 cells elongate neurites, and are in a reversible cell-cycle-arrested state. In contrast, these cells irreversibly differentiate and ... Read more >>

Nucleic Acids Res (Nucleic acids research)
[2016, 44(11):5105-5122]

Cited: 8 times

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miR-199a Links MeCP2 with mTOR Signaling and Its Dysregulation Leads to Rett Syndrome Phenotypes.

Keita Tsujimura, Koichiro Irie, Hideyuki Nakashima, Yoshihiro Egashira, Yoichiro Fukao, Masayuki Fujiwara, Masayuki Itoh, Masahiro Uesaka, Takuya Imamura, Yasukazu Nakahata, Yui Yamashita, Takaya Abe, Shigeo Takamori, Kinichi Nakashima,

Rett syndrome (RTT) is a neurodevelopmental disorder caused by MECP2 mutations. Although emerging evidence suggests that MeCP2 deficiency is associated with dysregulation of mechanistic target of rapamycin (mTOR), which functions as a hub for various signaling pathways, the mechanism underlying this association and the molecular pathophysiology of RTT remain elusive. ... Read more >>

Cell Rep (Cell reports)
[2015, 12(11):1887-1901]

Cited: 38 times

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Identification of hypothalamic arcuate nucleus-specific enhancer region of Kiss1 gene in mice.

Teppei Goto, Junko Tomikawa, Kana Ikegami, Shiori Minabe, Hitomi Abe, Tatsuya Fukanuma, Takuya Imamura, Kenji Takase, Makoto Sanbo, Koichi Tomita, Masumi Hirabayashi, Kei-ichiro Maeda, Hiroko Tsukamura, Yoshihisa Uenoyama,

Pulsatile secretion of GnRH plays a pivotal role in follicular development via stimulating tonic gonadotropin secretion in mammals. Kisspeptin neurons, located in the arcuate nucleus (ARC), are considered to be an intrinsic source of the GnRH pulse generator. The present study aimed to determine ARC-specific enhancer(s) of the Kiss1 gene ... Read more >>

Mol Endocrinol (Molecular endocrinology (Baltimore, Md.))
[2015, 29(1):121-129]

Cited: 11 times

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Gene activation-associated long noncoding RNAs function in mouse preimplantation development.

Nobuhiko Hamazaki, Masahiro Uesaka, Kinichi Nakashima, Kiyokazu Agata, Takuya Imamura,

In mice, zygotic activation occurs for a wide variety of genes, mainly at the 2-cell stage. Long noncoding RNAs (lncRNAs) are increasingly being recognized as modulators of gene expression. In this study, directional RNA-seq of MII oocytes and 2-cell embryos identified more than 1000 divergently transcribed lncRNA/mRNA gene pairs. Expression ... Read more >>

Development (Development (Cambridge, England))
[2015, 142(5):910-920]

Cited: 36 times

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Bidirectional promoters are the major source of gene activation-associated non-coding RNAs in mammals.

Masahiro Uesaka, Osamu Nishimura, Yasuhiro Go, Kinichi Nakashima, Kiyokazu Agata, Takuya Imamura,

<h4>Background</h4>The majority of non-coding RNAs (ncRNAs) involved in mRNA metabolism in mammals have been believed to downregulate the corresponding mRNA expression level in a pre- or post-transcriptional manner by forming short or long ncRNA-mRNA duplex structures. Information on non-duplex-forming long ncRNAs is now also rapidly accumulating. To examine the directional ... Read more >>

BMC Genomics (BMC genomics)
[2014, 15:35]

Cited: 54 times

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Epigenetic regulation of Kiss1 gene expression mediating estrogen-positive feedback action in the mouse brain.

Junko Tomikawa, Yoshihisa Uenoyama, Makiko Ozawa, Tatsuya Fukanuma, Kenji Takase, Teppei Goto, Hitomi Abe, Nahoko Ieda, Shiori Minabe, Chikaya Deura, Naoko Inoue, Makoto Sanbo, Koichi Tomita, Masumi Hirabayashi, Satoshi Tanaka, Takuya Imamura, Hiroaki Okamura, Kei-ichiro Maeda, Hiroko Tsukamura,

This study aims to determine the epigenetic mechanism regulating Kiss1 gene expression in the anteroventral periventricular nucleus (AVPV) to understand the mechanism underlying estrogen-positive feedback action on gonadotropin-releasing hormone/gonadotropin surge. We investigated estrogen regulation of the epigenetic status of the mouse AVPV Kiss1 gene locus in comparison with the arcuate ... Read more >>

Proc Natl Acad Sci U S A (Proceedings of the National Academy of Sciences of the United States of America)
[2012, 109(20):E1294-301]

Cited: 65 times

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Single-stranded noncoding RNAs mediate local epigenetic alterations at gene promoters in rat cell lines.

Junko Tomikawa, Hiroko Shimokawa, Masahiro Uesaka, Naoki Yamamoto, Yuji Mori, Hiroko Tsukamura, Kei-ichiro Maeda, Takuya Imamura,

A growing number of noncoding RNAs (ncRNAs) are thought to be involved in sequence-specific alterations of epigenetic processes, mostly causing gene repression. In this study, promoter-associated ncRNAs (pancRNAs >200 nucleotides in size) that were endogenously generated from the sense strand at Map2b, antisense strand at Nefl, and both strands at ... Read more >>

J Biol Chem (The Journal of biological chemistry)
[2011, 286(40):34788-34799]

Cited: 20 times

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Involvement of brain ketone bodies and the noradrenergic pathway in diabetic hyperphagia in rats.

Kinuyo Iwata, Mika Kinoshita, Shunji Yamada, Takuya Imamura, Yoshihisa Uenoyama, Hiroko Tsukamura, Kei-Ichiro Maeda,

Uncontrolled type 1 diabetes leads to hyperphagia and severe ketosis. This study was conducted to test the hypothesis that ketone bodies act on the hindbrain as a starvation signal to induce diabetic hyperphagia. Injection of an inhibitor of monocarboxylate transporter 1, a ketone body transporter, into the fourth ventricle normalized ... Read more >>

J Physiol Sci (The journal of physiological sciences : JPS)
[2011, 61(2):103-113]

Cited: 14 times

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Epigenetic setting for long-term expression of estrogen receptor α and androgen receptor in cells.

Takuya Imamura,

Epigenetic regulation of the nuclear estrogen and androgen receptors, ER and AR, constitutes the molecular basis for the long-lasting effects of sex steroids on gene expression in cells. The effects prevail at hundreds of gene loci in the proximity of estrogen- and androgen-responsive elements and many more such loci through ... Read more >>

Horm Behav (Hormones and behavior)
[2011, 59(3):345-352]

Cited: 8 times

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