Faculty Profiles - SAKAMOTO Hirotaka

Papers - SAKAMOTO Hirotaka

Division display 21 - 40 of about 110 ／ All the affair displays >>

In vivo processing and release into the circulation of GFP fusion protein in arginine vasopressin enhanced GFP transgenic rats: response to osmotic stimulation Reviewed

Keita Satoh, Takumi Oti, Akiko Katoh, Yoichi Ueta, John F. Morris, Tatsuya Sakamoto, Hirotaka Sakamoto*

FEBS JOURNAL 282 ( 13 ) 2488 - 2499 2015.7

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Arginine vasopressin (AVP) is a neurohypophysial hormone synthesized as a part of a prepropeptide precursor containing the signal peptide, AVP hormone, AVP-associated neurophysin II and copeptin in the hypothalamic neurosecretory neurons. A transgenic (Tg) rat line expressing the AVP-eGFP fusion gene has been generated. To establish the AVP-eGFP Tg rat as a unique model for an analysis of AVP dynamics invivo, we first examined the invivo molecular dynamics of the AVP-eGFP fusion gene, and then the release of GFP in response to physiological stimuli. Double immunoelectron microscopy demonstrated that GFP was specifically localized in neurosecretory vesicles of AVP neurons in this Tg rat. After stimulation of the posterior pituitary with high potassium we demonstrated the exocytosis of AVP neurosecretory vesicles containing GFP at the ultrastructural level. Biochemical analyses indicated that the AVP-eGFP fusion gene is subjected to invivo post-translational modifications like the native AVP gene, and is packaged into neurosecretory vesicles as a fusion protein: copeptin(1-14)-GFP. Moreover, GFP release into the circulating blood appeared to be augmented after osmotic stimulation, like native AVP. Thus, here we show for the first time the invivo molecular processing of the AVP-eGFP fusion gene and stimulated secretion after osmotic stimulation in rats. Because GFP behaved like native AVP in the hypothalamo-pituitary axis, and in particular was released into the circulation in response to a physiological stimulus, the AVP-eGFP Tg rat model appears to be a powerful tool for analyzing neuroendocrine systems at the organismal level.

DOI： 10.1111/febs.13291

Androgen regulates the sexually dimorphic gastrin-releasing peptide system in the lumbar spinal cord that mediates male sexual function Reviewed

Hirotaka Sakamoto*, Keiko Takanami, Damian G. Zuloaga, Ken-ichi Matsuda, Cynthia L. Jordan, S. Marc Breedlove, Mitsuhiro Kawata

ENDOCRINOLOGY 150 ( 8 ) 3672 - 3679 2009.8

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ENDOCRINE SOC

A collection of neurons in the upper lumbar spinal cord of male rats projects to the lower lumbar spinal cord, releasing gastrin-releasing peptide (GRP) onto somatic and autonomic centers known to regulate male sexual reflexes such as erection and ejaculation. Because these reflexes are androgen dependent, we asked whether manipulating levels of androgen in adult rats would affect GRP expression in this spinal center. We found that castration resulted, 28 d later, in a profound decrease in the expression of GRP in the spinal cord, as reflected in immunocytochemistry and competitive ELISA for the protein as well as real-time quantitative PCR for the transcript. These effects were prevented if the castrates were treated with testosterone propionate. Genetically male (XY) rats with the dysfunctional testicular feminization allele for the androgen receptor (AR) displayed GRP mRNA and protein levels in the spinal cord similar to those of females, indicating that androgen normally maintains the system through AR. We saw no effect of castration or the testicular feminization allele on expression of the receptor for GRP in the spinal cord, but castration did reduce expression of AR transcripts within the spinal cord as revealed by real-time quantitative PCR and Western blots. Taken together, these results suggest that androgen signaling plays a pivotal role in the regulation of GRP expression in male lumbar spinal cord. A greater understanding of how androgen modulates the spinal GRP system might lead to new therapeutic approaches to male sexual dysfunction. (Endocrinology 150: 3672-3679, 2009)

DOI： 10.1210/en.2008-1791

Stress affects a gastrin-releasing peptide system in the spinal cord that mediates sexual function: Implications for psychogenic erectile dysfunction Reviewed

Hirotaka Sakamoto*, Ken-Ichi Matsuda, Damian G. Zuloaga, Nobuko Nishiura, Keiko Takanami, Cynthia L. Jordan, S. Marc Breedlove, Mitsuhiro Kawata

PLoS ONE 4 ( 1 ) e4276 2009.1

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：PUBLIC LIBRARY SCIENCE

Background: Many men suffering from stress, including post-traumatic stress disorder (PTSD), report sexual dysfunction, which is traditionally treated via psychological counseling. Recently, we identified a gastrin-releasing peptide (GRP) system in the lumbar spinal cord that is a primary mediator for male reproductive functions.
Methodology/Principal Findings: To ask whether an acute severe stress could alter the male specific GRP system, we used a single-prolonged stress (SPS), a putative rat model for PTSD in the present study. Exposure of SPS to male rats decreases both the local content and axonal distribution of GRP in the lower lumbar spinal cord and results in an attenuation of penile reflexes in vivo. Remarkably, pharmacological stimulation of GRP receptors restores penile reflexes in SPS-exposed males, and induces spontaneous ejaculation in a dose-dependent manner. Furthermore, although the level of plasma testosterone is normal 7 days after SPS exposure, we found a significant decrease in the expression of androgen receptor protein in this spinal center.
Conclusions/Significance: We conclude that the spinal GRP system appears to be a stress-vulnerable center for male reproductive functions, which may provide new insight into a clinical target for the treatment of erectile dysfunction triggered by stress and psychiatric disorders.

DOI： 10.1371/journal.pone.0004276

Sexually dimorphic gastrin releasing peptide system in the spinal cord controls male reproductive functions Reviewed

Hirotaka Sakamoto*, Ken-Ichi Matsuda, Damian G. Zuloaga, Hisayuki Hongu, Etsuko Wada, Keiji Wada, Cynthia L. Jordan, S. Marc Breedlove, Mitsuhiro Kawata

Nature Neuroscience 11 ( 6 ) 634 - 636 2008.6

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

Neurons in the upper lumbar spinal cord project axons containing gastrin-releasing peptide (GRP) to innervate lower lumbar regions controlling erection and ejaculation. This system is vestigial in female rats and in males with genetic dysfunction of androgen receptors, but in male rats, pharmacological stimulation of spinal GRP receptors restores penile reflexes and ejaculation after castration. GRP offers new avenues for understanding potential therapeutic approaches to masculine reproductive dysfunction.

DOI： 10.1038/nn.2126

Expression of G protein-coupled receptor-30, a g protein-coupled membrane estrogen receptor, in oxytocin neurons of the rat paraventricular and supraoptic nuclei Reviewed

Hirotaka Sakamoto*, Ken-Ichi Matsuda, Koji Hosokawa, Mayumi Nishi, John F. Morris, Eric R. Prossnitz, Mitsuhiro Kawata

ENDOCRINOLOGY 148 ( 12 ) 5842 - 5850 2007.12

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ENDOCRINE SOC

The regulatory actions of estrogens on magnocellular oxytocin (OT) neurons of the paraventricular and supraoptic nuclei are well documented. Although the expression and distribution of nuclear estrogen receptor-beta, but not estrogen receptor-alpha, in the OT neuron has been described, the nuclear receptors may not explain all aspects of estrogen function in the hypothalamic OT neuron. Recently a G protein-coupled receptor (GPR) for estrogens, GPR30, has been identified as a membrane-localized estrogen receptor in several cancer cell lines. In this study, we therefore investigated the expression and localization of GPR30 in magnocellular OT neurons to understand the mode of rapid estrogen actions within these neurons. Here we show that, in the paraventricular nucleus and supraoptic nucleus, GPR30 is expressed in magnocellular OT neurons at both mRNA and protein levels but is not expressed in vasopressin neurons. Specific markers for intracellular organelles and immunoelectron microscopy revealed that GPR30 was localized mainly in the Golgi apparatus of the neurons but could not be detected at the cell surface. In addition, the expression of GPR30 is also detected in the neurohypophysis. These results suggest that GPR30 may serve primarily as a nongenomic transducer of estrogen actions in the hypothalamo-neurohypophyseal system.

DOI： 10.1210/en.2007-0436

Keratinocyte-driven dermal collagen formation in the axolotl skin

Ayaka Ohashi, Hirotaka Sakamoto, Junpei Kuroda, Yohei Kondo, Yasuhiro Kamei, Shigenori Nonaka, Saya Furukawa, Sakiya Yamamoto, Akira Satoh

Nature Communications 16 ( 1 ) 2025.2

Volume X-Ray Micro-Computed Tomography Analysis of the Early Cephalized Central Nervous System in a Marine Flatworm, Stylochoplana pusilla. Reviewed International journal

Takanori Ikenaga, Aoshi Kobayashi, Akihisa Takeuchi, Kentaro Uesugi, Takanobu Maezawa, Norito Shibata, Tatsuya Sakamoto, Hirotaka Sakamoto

Zoological Science 41 ( 3 ) 281 - 289 2024.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Platyhelminthes are a phylum of simple bilaterian invertebrates with prototypic body systems. Compared with non-bilaterians such as cnidarians, the bilaterians are likely to exhibit integrated free-moving behaviors, which require a concentrated nervous system "brain" rather than the distributed nervous system of radiatans. Marine flatworms have an early cephalized 'central' nervous system compared not only with non-bilaterians but also with parasitic flatworms or freshwater planarians. In this study, we used the marine flatworm Stylochoplana pusilla as an excellent model organism in Platyhelminthes because of the early cephalized central nervous system. Here, we investigated the three-dimensional structures of the flatworm central nervous system by the use of X-ray micro-computed tomography (micro-CT) in a synchrotron radiation facility. We found that the obtained tomographic images were sufficient to discriminate some characteristic structures of the nervous system, including nerve cords around the cephalic ganglion, mushroom body-like structures, and putative optic nerves forming an optic commissure-like structure. Through the micro-CT imaging, we could obtain undistorted serial section images, permitting us to visualize precise spatial relationships of neuronal subpopulations and nerve tracts. 3-D micro-CT is very effective in the volume analysis of the nervous system at the cellular level; the methodology is straightforward and could be applied to many other non-model organisms.

DOI： 10.2108/zs230082

Membrane-Targeted palGFP Predominantly Localizes to the Plasma Membrane but not to Neurosecretory Vesicle Membranes in Rat Oxytocin Neurons. Reviewed International journal

Hirotaka Sakamoto, Ayumu Inutsuka

Acta histochemica et cytochemica 57 ( 2 ) 85 - 88 2024.4

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Recent advances in viral vector technology, specifically using adeno-associated virus (AAV) vectors, have significantly expanded possibilities in neuronal tracing. We have utilized the Cre/loxP system in combination with AAV techniques in rats to explore the subcellular localization of palmitoylation signal-tagged GFP (palGFP) in oxytocin-producing neurosecretory neurons. A distinctive branching pattern of single axons was observed at the level of the terminals in the posterior pituitary. Despite challenges in detecting palGFP signals by fluorescent microscopy, immunoelectron microscopy demonstrated predominant localization on the plasma membrane, with a minor presence on the neurosecretory vesicle membrane. These findings suggest that membrane-anchored palGFP may undergo exocytosis, translocating from the plasma membrane to the neurosecretory vesicle membrane. In this study, we observed characteristic axon terminal structures in the posterior pituitary of oxytocin neurons. This study indicates the importance of understanding the plasma membrane-specific sorting system in neuronal membrane migration and encourages future studies on the underlying mechanisms.

DOI： 10.1267/ahc.24-00001

Model systems for discovering evolutionary singularity of bilaterian physiological regulation: lessons from studies on simple/primitive flatworms Reviewed International journal

Shunsuke Mori, Aoshi Kobayashi, Hirotaka Sakamoto, Mayuko Hamada, Tatsuya Sakamoto, Ryo Nakamura

Biophysics and Physicobiology 21 e211012 2024.3

Function of gastrin-releasing peptide receptors in ocular itch transmission in the mouse trigeminal sensory system Reviewed International journal

Keiko Takanami, Masaya Kuroiwa, Ren Ishikawa, Yuji Imai, Akane Oishi, Midori Hashino, Yasushi Shimoda, Hirotaka Sakamoto, Tsuyoshi Koide

Frontiers in Molecular Neuroscience 16 1280024 2023.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers Media SA

The prevalence of allergic conjunctivitis in itchy eyes has increased constantly worldwide owing to environmental pollution. Currently, anti-allergic and antihistaminic eye drops are used; however, there are many unknown aspects about the neural circuits that transmit itchy eyes. We focused on the gastrin-releasing peptide (GRP) and GRP receptor (GRPR), which are reportedly involved in itch transmission in the spinal somatosensory system, to determine whether the GRP system is involved in itch neurotransmission of the eyes in the trigeminal sensory system. First, the instillation of itch mediators, such as histamine (His) and non-histaminergic itch mediator chloroquine (CQ), exhibited concentration-dependent high levels of eye scratching behavior, with a significant sex differences observed in the case of His. Histological analysis revealed that His and CQ significantly increased the neural activity of GRPR-expressing neurons in the caudal part of the spinal trigeminal nucleus of the medulla oblongata in GRPR transgenic mice. We administered a GRPR antagonist or bombesin-saporin to ablate GRPR-expressing neurons, followed by His or CQ instillation, and observed a decrease in CQ-induced eye-scratching behavior in the toxin experiments. Intracisternal administration of neuromedin C (NMC), a GRPR agonist, resulted in dose-dependent excessive facial scratching behavior, despite the absence of an itch stimulus on the face. To our knowledge, this is the first study to demonstrate that non-histaminergic itchy eyes were transmitted centrally via GRPR-expressing neurons in the trigeminal sensory system, and that NMC in the medulla oblongata evoked facial itching.

DOI： 10.3389/fnmol.2023.1280024

Amyloid deposition through endocytosis in vascular endothelial cells. Reviewed International journal

Seiji Nishikage, Akira Fujisawa, Hiromi Endoh, Hirotaka Sakamoto, Tomohide Suzuki, Maki Kanzawa, Shinichi Ishii, Mitsumasa Okano, Eriko Nitta, Kimikazu Yakushijin, Hidesaku Asakura, Kandai Nozu, Ryo Nitta, Yoshio Katayama, Kazuhiko Sakaguchi

Experimental hematology 129 104129 2023.11

Language：English Publishing type：Research paper (scientific journal)

No mechanistic lead is known for establishing AL amyloid deposits in organs. We here report an electron microscopic (EM) analysis in a case of intestinal AL amyloidosis before initiating treatment for amyloidosis. The dense deposits of amyloid fibrils are concentrated around the small blood vessels in the submucosal area of intestinal tissue. Surprisingly, we observed endothelial cells (ECs) of blood vessels containing plenty of endocytotic (pinocytotic) and transcytotic vesicles at the luminal side and above the basement membrane, indicating the one-way active trafficking of either the immunoglobulin (Ig) light chain or preassembled amyloid fibrils from the luminal side of ECs to the extraluminal area of ECs. Immunoelectron microscopy displayed that the immuno-gold signals were observed in the vascular cavity and the subendothelial area of amyloid deposits. However, there is no sign of an Ig light chain in pinocytotic vesicles. Therefore, the intestinal ECs may actively pump out mainly the preassembled amyloid fibrils (not light chains) from the blood stream into the subendothelial area as a physiologic function.

DOI： 10.1016/j.exphem.2023.11.003

Chronic corticosterone exposure evokes itch hypersensitivity and sexual dysfunction in male rats: Relationship between the two distinct gastrin-releasing peptide systems in the spinal cord Reviewed International journal

Keiko Takanami, Makoto Morishita, Tatsuya Sakamoto, Hirotaka Sakamoto

General and Comparative Endocrinology 339 114289 - 114289 2023.8

Spinal Transection Switches the Effect of Metabotropic Glutamate Receptor Subtype 7 from the Facilitation to Inhibition of Ejaculation. Reviewed International journal

Miwako Masugi-Tokita, Shigehisa Kubota, Kenichi Kobayashi, Tetsuya Yoshida, Susumu Kageyama, Hirotaka Sakamoto, Akihiro Kawauchi

Neuroscience 509 10 - 19 2023.1

Language：English Publishing type：Research paper (scientific journal)

Metabotropic glutamate receptor subtype 7 (mGluR7) is a member of the group III mGluRs, which localize to presynaptic active zones of the central nervous system. We previously reported that mGluR7 knockout (KO) mice exhibit ejaculatory disorders, although they have normal sexual motivation. We hypothesized that mGluR7 regulates ejaculation by potentiating the excitability of the neural circuit in the lumbosacral spinal cord, because administration of the mGluR7-selective antagonist into that region inhibits drug-induced ejaculation. In the present study, to elucidate the mechanism of impaired ejaculation in mGluR7 KO mice, we eliminated the influence of the brain by spinal transection (spinalization). Unexpectedly, sexual responses of male mGluR7 KO mice were stronger than those of wild-type mice after spinalization. Histological examination indicated that mGluR7 controls sympathetic neurons as well as parasympathetic neurons. In view of the complexity of its synaptic regulation, mGluR7 might control ejaculation by multi-level and multi-modal mechanisms. Our study provides insight into the mechanism of ejaculation as well as a strategy for future therapies to treat ejaculatory disorders in humans.

DOI： 10.1016/j.neuroscience.2022.11.012

Mating experiences with the same partner enhanced mating activities of naïve male medaka fish. Reviewed International journal

Masahiro Daimon, Takafumi Katsumura, Hirotaka Sakamoto, Satoshi Ansai, Hideaki Takeuchi

Scientific reports 12 ( 1 ) 19665 - 19665 2022.11

Language：English Publishing type：Research paper (scientific journal)

Mating experience shapes male mating behavior across species, from insects, fish, and birds, to rodents. Here, we investigated the effect of multiple mating experiences on male mating behavior in "naïve" (defined as sexually inexperienced) male medaka fish. The latency to mate with the same female partner significantly decreased after the second encounter, whereas when the partner was changed, the latency to mate was not decreased. These findings suggest that mating experiences enhanced the mating activity of naïve males for the familiar female, but not for an unfamiliar female. In contrast, the mating experiences of "experienced" (defined as those having mated > 7 times) males with the same partner did not influence their latency to mate. Furthermore, we identified 10 highly and differentially expressed genes in the brains of the naïve males after the mating experience and revealed 3 genes that are required for a functional cascade of the thyroid hormone system. Together, these findings suggest that the mating experience of naïve male medaka fish influences their mating behaviors, with neural changes triggered by thyroid hormone activation in the brain.

DOI： 10.1038/s41598-022-23871-w

Aquaporin regulates cell rounding through vacuole formation during endothelial-to-hematopoietic transition Reviewed International journal

Yuki Sato, Mugiho Shigematsu, Maria Shibata-Kanno, Sho Maejima, Chie Tamura, Hirotaka Sakamoto

Development 150 ( 11 ) dev201275 2022.9

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Cold Spring Harbor Laboratory

Endothelial-to-hematopoietic transition (EHT) is crucial for hematopoietic stem cell (HSC) generation. During EHT, the morphology of hemogenic endothelial cells (HECs) changes from flat and adherent to spherical HSCs, which detach from the dorsal aorta. HECs attain a rounded shape in a mitosis-independent manner before cell adhesion termination, suggesting an atypical cell-rounding mechanism. However, the direct mechanisms underlying this change in cell morphology during EHT remain unclear. Here, we show that large vacuoles were transiently formed in HECs and that aquaporin-1 (AQP1) was localized in the vacuole and plasma membranes. Overexpression of AQP1 in non-HECs induced ectopic vacuole expansion, cell rounding, and subsequent cell detachment from the endothelium into the bloodstream, mimicking EHT. Loss of redundant AQP functions by CRISPR/Cas9 gene editing in HECs impeded the morphological EHT. Our findings provide the first evidence indicating that morphological segregation of HSCs from endothelial cells is regulated by water influx into vacuoles. These findings provide important insights for further exploration of the mechanisms underlying cell/tissue morphogenesis through water-adoptive cellular responses.

DOI： 10.1101/2022.09.03.506460

Evolutionary differentiation of androgen receptor ohnologs is responsible for the development of androgen-dependent unique sexual characteristics in a teleost fish Reviewed International coauthorship International journal

Yukiko Ogino, Satoshi Ansai, Eiji Watanabe, Masaki Yasugi, Yukitoshi Katayama, Hirotaka Sakamoto, Keigo Okamoto, Kataaki Okubo, Yasuhiro Yamamoto, Ikuyo HARA, Touko Yamazaki, Ai Kato, Yasuhiro Kamei, Kiyoshi Naruse, Kohei Ohta, Hajime Ogino, Tatsuya Sakamoto, Shinichi Miyagawa, TOMOMI SATO, Gen Yamada, Michael Baker, Taisen Iguchi

Nature Communications 14 ( 1 ) 1428 2022.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Research Square Platform LLC

Abstract

Teleost fishes exhibit complex unique sexual characteristics, such as fin enlargement and courtship display, in response to androgens. However, the molecular mechanisms underlying their evolutionary acquisition remain largely unknown. To address this question, we analysed medaka (Oryzias latipes) mutants deficient in androgen receptor ohnologs (ara and arb) generated by the teleost-specific whole-genome duplication event (TSGD). We discovered that both ar ohnologs are not required for spermatogenesis and appear to be functionally redundant for courtship display in males, while both copies were necessary for their reproductive success; ara was required for tooth enlargement and behavioural attractiveness, while arb for male-specific fin morphogenesis and sexual motivation. We further showed that the differences in both the transcription of the two ars, cellular localisation of their encoded proteins and their downstream genetic programs could be responsible for the phenotypic diversity between the ara and arb mutants. These findings suggest that the ar ohnologs have diverged in the teleost lineage in two different ways: First through the loss of their roles in spermatogenesis and second through the gene duplication followed by functional differentiation that has likely resolved the pleiotropic roles derived from their ancestral gene. Thus, our results provide insights into how genome duplication impacts the massive diversification of sexual characteristics in the teleost lineage.

DOI： 10.21203/rs.3.rs-1848626/v1

Other Link： https://www.researchsquare.com/article/rs-1848626/v1.html

Characterization of the expression of gastrin-releasing peptide and its receptor in the trigeminal and spinal somatosensory systems of Japanese macaque monkeys: Insight into humans. Reviewed International coauthorship International journal

Keiko Takanami, Takumi Oti, Yasuhisa Kobayashi, Koki Hasegawa, Takashi Ito, Naoaki Tsutsui, Yasumasa Ueda, Earl Carstens, Tatsuya Sakamoto, Hirotaka Sakamoto

The Journal of Comparative Neurology 530 ( 16 ) 2804 - 2819 2022.6

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Gastrin-releasing peptide (GRP) and its receptor (GRPR) have been identified as itch mediators in the spinal and trigeminal somatosensory systems in rodents. In primates, there are few reports of GRP/GRPR expression or function in the spinal sensory system and virtually nothing is known in the trigeminal system. The aim of the present study was to characterize GRP and GRPR in the trigeminal and spinal somatosensory system of Japanese macaque monkeys (Macaca fuscata). cDNA encoding GRP was isolated from the macaque dorsal root ganglion (DRG) and exhibited an amino acid sequence that was highly conserved among mammals and especially in primates. Immunohistochemical analysis demonstrated that GRP was expressed mainly in the small-sized trigeminal ganglion and DRG in adult macaque monkeys. Densely stained GRP-immunoreactive (ir) fibers were observed in superficial layers of the spinal trigeminal nucleus caudalis (Sp5C) and the spinal cord. In contrast, GRP-ir fibers were rarely observed in the principal sensory trigeminal nucleus and oral and interpolar divisions of the spinal trigeminal nucleus. cDNA cloning, in situ hybridization, and Western blot revealed substantial expression of GRPR mRNA and GRPR protein in the macaque spinal dorsal horn and Sp5C. Our Western ligand blot and ligand derivative stain for GRPR revealed that GRP directly bound in the macaque Sp5C and spinal dorsal horn as reported in rodents. Finally, GRP-ir fibers were also detected in the human spinal dorsal horn. The spinal and trigeminal itch neural circuits labeled with GRP and GRPR appear to function also in primates.

DOI： 10.1002/cne.25376

Lattice-patterned collagen fibers and their dynamics in axolotl skin regeneration Reviewed International journal

Rena Kashimoto, Saya Furukawa, Sakiya Yamamoto, Yasuhiro Kamei, Joe Sakamoto, Shigenori Nonaka, Tomonobu M. Watanabe, Tatsuya Sakamoto, Hirotaka Sakamoto, Akira Satoh

iScience 25 ( 7 ) 104524 - 104524 2022.6

Nanobody-Based RFP-Dependent Cre Recombinase for Selective Anterograde Tracing in RFP-Expressing Transgenic Animals Reviewed International journal

Ayumu Inutsuka, Sho Maejima, Hiroyuki Mizoguchi, Ryosuke Kaneko, Rei Nomura, Keiko Takanami, Hirotaka Sakamoto, Tatsushi Onaka

Communications Biology 5 ( 1 ) 979 2022.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Research Square Platform LLC

Abstract

Transgenic animals expressing fluorescent proteins are widely used to label specific cells and proteins. GFP-dependent gene regulation utilizes these lines to manipulate gene expression; however, its application has been limited to fluorescent proteins derived from Aequorea jellyfish. By using a split Cre recombinase fused with mCherry-binding nanobodies or designed ankyrin repeat proteins, we created Cre recombinase dependent on red fluorescent protein (RFP) (Cre-DOR). Functional binding units for monomeric RFPs (mCherry, mRFP1) are different from those for dimeric RFP (tdTomato). We confirmed target RFP-dependent gene expression in the mouse cerebral cortex using stereotaxic injection of adeno-associated virus vectors including Cre-DOR, target RFP, and reporter GFP vector. We found highly selective GFP expression in RFP-positive cortical neurons with 93.5 ± 0.6% of GFP-positive cells being mRFP1-positive. In estrogen receptor-beta (Esr2)-mRFP1 mice, we confirmed that Cre-DOR can be used for selective expression of membrane-bound GFP in the paraventricular nucleus of the hypothalamus. The neural projection from Esr2-expressing neurons in the hypothalamic paraventricular nucleus to the posterior pituitary was visualized by Cre-DOR. In gastrin-releasing peptide receptor (Grpr)-mRFP1 rats, we similarly achieved anterograde tracing of Grpr-expressing neurons in the medial amygdala and found that they are projecting axons to the posterior bed nucleus of the stria terminalis. Cellular localization of RFPs affects recombination efficiency of Cre-DOR, and light and chemical-induced nuclear translocation of an RFP-fused protein can increase or decrease Cre-DOR efficiency. Our results provide a method for manipulating gene expression in specific cells expressing RFPs and expand the repertory of nanobody-based genetic tools.

DOI： 10.21203/rs.3.rs-1234462/v1

Other Link： https://www.researchsquare.com/article/rs-1234462/v1.html

Behavioural osmoregulation during land invasion in fish: Prandial drinking and wetting of the dry skin. Reviewed International journal

Yukitoshi Katayama, Takehiro Tsukada, Susumu Hyodo, Hirotaka Sakamoto, Tatsuya Sakamoto

PLoS ONE 17 ( 12 ) e0277968 2022

Language：English Publishing type：Research paper (scientific journal)

Osmoregulatory behaviours should have evolutionarily modified for terrestrialisation of vertebrates. In mammals, sensations of buccal food and drying have immediate effects on postprandial thirst to prevent future systemic dehydration, and is thereby considered to be 'anticipatory thirst'. However, it remains unclear whether such an anticipatory response has been acquired in the non-tetrapod lineage. Using the mudskipper goby (Periophthalmus modestus) as a semi-terrestrial ray-finned fish, we herein investigated postprandial drinking and other unique features like full-body 'rolling' over on the back although these behaviours had not been considered to have osmoregulatory functions. In our observations on tidal flats, mudskippers migrated into water areas within a minute after terrestrial eating, and exhibited rolling behaviour with accompanying pectoral-fin movements. In aquarium experiments, frequency of migration into a water area for drinking increased within a few minutes after eating onset, without systemic dehydration. During their low humidity exposure, frequency of the rolling behaviour and pectoral-fin movements increased by more than five times to moisten the skin before systemic dehydration. These findings suggest anticipatory responses which arise from oral/gastrointestinal and cutaneous sensation in the goby. These sensation and motivation seem to have evolved in distantly related species in order to solve osmoregulatory challenges during terrestrialisation.

DOI： 10.1371/journal.pone.0277968

　 PREV - NEXT 　

1
2
3
4
5
6