Faculty Profiles - TAZAKI Akira

Papers - TAZAKI Akira

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A unique system that can sensitively assess the risk of chemical leukoderma by using murine tail skin Reviewed

Machiko Iida, Akira Tazaki, Yuqi Deng, Wei Chen, Ichiro Yajima, Lisa Kondo-Ida, Kazunori Hashimoto, Nobutaka Ohgami, Masashi Kato

CHEMOSPHERE Vol. 235 page： 713 - 718 2019.11

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

Chemical leukoderma is a patchy hypopigmentation in the skin. Phenol derivatives such as raspberry ketone have been reported to cause the development of occupationally induced leukoderma. Recently, 2% (w/w) rhododenol, a reduced form of raspberry ketone used in a skin-lightning agent, also caused the development of leukoderma in >16,000 users, about 2% of all users, in Asian countries including Japan. However, a method for assessing the risk of leukoderma caused by 2% rhododenol has not been established despite the fact that the development of leukoderma caused by 30% rhododenol was previously shown in animal experiments. Establishment of a novel technique for risk assessment of leukoderma in humans caused by external treatment with chemicals is needed to prevent a possible future chemical disaster. This study demonstrated that external treatment with 2% rhododenol and the same concentration of raspberry ketone caused the development of leukoderma in murine tail skin without exception with significant decreases in the amount of melanin and number of melanocytes in the epidermis. Thus, a novel in vivo technique that can assess the risk of leukoderma caused by 2% rhododenol was developed. The unique technique using tail skin has the potential to prevent chemical leukoderma in the future. (C) 2019 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2019.06.185

Histological analysis of the skin of Abca1-deleted mice: A potential model for dry skin Reviewed International journal

Yuqi Deng, Nobutaka Ohgami, Machiko Iida, Akira Tazaki, Atsushi Intoh, Lisa Kondo-Ida, Rui Lu, Toyonori Tsuzuki, Shinji Yokoyama, Masashi Kato

EUROPEAN JOURNAL OF DERMATOLOGY Vol. 29 ( 5 ) page： 549 - 551 2019.9

Chromium-mediated hyperpigmentation of skin in male tannery workers in Bangladesh Reviewed International coauthorship

M. M. Aeorangajeb Al Hossain, Ichiro Yajima, Akira Tazaki, Huadong Xu, Md Saheduzzaman, Nobutaka Ohgami, Nazmul Ahsan, Anwarul Azim Akhand, Masashi Kato

CHEMOSPHERE Vol. 229 page： 611 - 617 2019.8

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

Since tannery workers in developing countries are chronically exposed to high levels of chromium (Cr), there are serious concerns about health problems. However, there has been limited study in which Cr levels were measured in tannery workers, who are chronically exposed to Cr. Our preliminary inspection showed that there was hyperpigmented skin in tannery workers. We therefore investigated the correlation between skin pigmentation levels digitally evaluated as L* values by using a reflectance spectrophotometer and Cr levels in skin appendages in 100 male tannery workers and in 49 male non-tannery workers in Bangladesh. Digitalized skin pigmentation levels of the face and feet in addition to Cr levels in hair and toenails in tannery workers were significantly higher than those in non-tannery workers in our univariate analysis. Spearman's rank correlation coefficient analysis showed significant correlation between duration of tannery work (years) and Cr levels in hair (r = 0.62) and toenails (r = 0.61). Our multivariate analysis also showed that Cr levels in hair and toenails were significantly correlated with digitalized skin pigmentation levels of the face and feet in addition to duration of tannery work in all participants. Thus, our results showed the development of hyperpigmented skin in tannery workers. Our results also suggested that hyperpigmented skin could be a useful diagnostic marker for chronic exposure to Cr. Furthermore, cutaneous L* value might be a convenient marker for detection of chronic Cr poisoning, since the digitalized values enable objective evaluation of skin pigmented levels by general people as well as dermatologists. (C) 2019 Published by Elsevier Ltd.

DOI： 10.1016/j.chemosphere.2019.04.112

Adsorption of molybdenum by melanin Reviewed International journal

Wei Chen, Kazunori Hashimoto, Yasuhiro Omata, Nobutaka Ohgami, Akira Tazaki, Yuqi Deng, Lisa Kondo-Ida, Atsushi Intoh, Masashi Kato

ENVIRONMENTAL HEALTH AND PREVENTIVE MEDICINE Vol. 24 ( 1 ) page： 36 - 36 2019.5

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

Background: Melanin is detectable in various sense organs including the skin in animals. It has been reported that melanin adsorbs toxic elements such as mercury, cadmium, and lead. In this study, we investigated the adsorption of molybdenum, which is widely recognized as a toxic element, by melanin.Methods: Molybdenum level of the mouse skin was measured by inductively coupled plasma mass spectrometry. The pigmentation level of murine skin was digitalized as the L* value by using a reflectance spectrophotometer. An in vitro adsorption assay was performed to confirm the interaction between molybdenum and melanin.Results: Our analysis of hairless mice with different levels of skin pigmentation showed that the level of molybdenum increased with an increase in the level of skin pigmentation (L* value). Moreover, our analysis by Spearman's correlation coefficient test showed a strong correlation (r = -0.9441, p < 0.0001) between L* value and molybdenum level. Our cell- free experiment using the Langmuir isotherm provided evidence for the adsorption of molybdenum by melanin. The maximum adsorption capacity of 1 mg of synthetic melanin for molybdenum was 131 mu g in theory.Conclusion: Our in vivo and in vitro results showed a new aspect of melanin as an adsorbent of molybdenum.

DOI： 10.1186/s12199-019-0791-y

Improvement of balance in young adults by a sound component at 100 Hz in music Reviewed Open Access

Huadong Xu, Nobutaka Ohgami, Tingchao He, Kazunori Hashimoto, Akira Tazaki, Kyoko Ohgami, Kozue Takeda, Masashi Kato

SCIENTIFIC REPORTS Vol. 8 ( 1 ) page： 16894 2018.11

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

About 80% of young people use personal listening devices (PLDs) including MP3 players to listen to music, which consists of sound components with various frequencies. Previous studies showed that exposure to noise of high intensities affected balance in humans. However, there is no information about a frequency-dependent effect of sound components in music from a PLD on balance in young people. In this study, we determined the associations between sound component levels (dB) at 100, 1000 and 4000 Hz in music from a portable listening device (PLD) and balance objectively determined by posturography in young adults (n = 110).We divided the subjects into two groups (low and high exposure groups) based on cut-off values of sound component levels at each frequency using receiver operating characteristic (ROC) curves. Balance in the high exposure group (>= 46.6 dB) at 100 Hz was significantly better than that in low exposure group in logistic regression models adjusted for sex, BMI, smoking status and alcohol intake, while there were no significant associations at 1000 and 4000 Hz. Thus, this study demonstrated for the first time that the sound component at 100 Hz with more than 46.6 dB in music improved balance in young adults.

DOI： 10.1038/s41598-018-35244-3

A disadvantageous effect of adsorption of barium by melanin on transforming activity Reviewed

Yasuhiro Omata, Masafumi Yoshinaga, Ichiro Yajima, Nobutaka Ohgami, Kazunori Hashimoto, Kaho Higashimura, Akira Tazaki, Masashi Kato

CHEMOSPHERE Vol. 210 page： 384 - 391 2018.11

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

At present, beneficial effects of melanin and harmful effects of barium have been reported. However, little is known about the adsorption of barium, and even less is known about the biological significance of adsorption of barium by melanin. In this study, we showed that there was a strong correlation between the digitalized level of skin pigmentation and barium level in murine skin compared to the correlations between skin pigmentation level and levels of homologous elements of barium (magnesium, calcium and strontium). The concentration of subcutaneously injected barium in skin with a high level of pigmentation was higher than that in skin with a low level of pigmentation. Our cell-free experiment using the Langmuir isotherm for adsorption of barium in synthetic melanin also provided direct evidence of adsorption of barium by melanin. We then investigated the biological significance of melanin mediated barium adsorption. We found barium-mediated increase in transforming activity in pig-mented melanocytes (melan-a) but not in unpigmented melanocytes (melan-c) after confirming that the barium level in melan-a melanocytes was 3.4-fold higher than that in melan-c melanocytes after culture of 5 mu M barium for 24 h. Taken together, our results not only indicate adsorption of barium by melanin in mice, cells and cell-free systems but also suggest a disadvantageous effect of adsorption of barium by melanin on transforming activity in cultured cells. (C) 2018 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2018.07.022

Salamander spinal cord regeneration: The ultimate positive control in vertebrate spinal cord regeneration Reviewed International coauthorship

Akira Tazaki, Elly M. Tanaka, Ji-Feng Fei

DEVELOPMENTAL BIOLOGY Vol. 432 ( 1 ) page： 63 - 71 2017.12

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Repairing injured tissues / organs is one of the major challenges for the maintenance of proper organ function in adulthood. In mammals, the central nervous system including the spinal cord, once established during embryonic development, has very limited capacity to regenerate. In contrast, salamanders such as axolotls can fully regenerate the injured spinal cord, making this a very powerful vertebrate model system for studying this process. Here we discuss the cellular and molecular requirements for spinal cord regeneration in the axolotl. The recent development of tools to test molecular function, including CRISPR-mediated gene editing, has lead to the identification of key players involved in the cell response to injury that ultimately leads to outgrowth of neural stem cells that are competent to replay the process of spinal cord development to replace the damaged/missing tissue.

DOI： 10.1016/j.ydbio.2017.09.034

Planar cell polarity-mediated induction of neural stem cell expansion during axolotl spinal cord regeneration Reviewed International coauthorship

Aida Rodrigo Albors, Akira Tazaki, Fabian Rost, Sergej Nowoshilow, Osvaldo Chara, Elly M. Tanaka

ELIFE Vol. 4 page： e10230 2015.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：ELIFE SCIENCES PUBLICATIONS LTD

Axolotls are uniquely able to mobilize neural stem cells to regenerate all missing regions of the spinal cord. How a neural stem cell under homeostasis converts after injury to a highly regenerative cell remains unknown. Here, we show that during regeneration, axolotl neural stem cells repress neurogenic genes and reactivate a transcriptional program similar to embryonic neuroepithelial cells. This dedifferentiation includes the acquisition of rapid cell cycles, the switch from neurogenic to proliferative divisions, and the re-expression of planar cell polarity (PCP) pathway components. We show that PCP induction is essential to reorient mitotic spindles along the anterior-posterior axis of elongation, and orthogonal to the cell apical-basal axis. Disruption of this property results in premature neurogenesis and halts regeneration. Our findings reveal a key role for PCP in coordinating the morphogenesis of spinal cord outgrowth with the switch from a homeostatic to a regenerative stem cell that restores missing tissue.

DOI： 10.7554/eLife.10230

3D Reconstitution of the Patterned Neural Tube from Embryonic Stem Cells Reviewed International coauthorship

Andrea Meinhardt, Dominic Eberle, Akira Tazaki, Adrian Ranga, Marco Niesche, Michaela Wilsch-Braeuninger, Agnieszka Stec, Gabriele Schackert, Matthias Lutolf, Elly M. Tanaka

STEM CELL REPORTS Vol. 3 ( 6 ) page： 987 - 99 2014.12

Language：English Publishing type：Research paper (scientific journal) Publisher：CELL PRESS

Inducing organogenesis in 3D culture is an important aspect of stem cell research. Anterior neural structures have been produced from large embryonic stem cell (ESC) aggregates, but the steps involved in patterning such complex structures have been ill defined, as embryoid bodies typically contained many cell types. Here we show that single mouse ESCs directly embedded in Matrigel or defined synthetic matrices under neural induction conditions can clonally form neuroepithelial cysts containing a single lumen in 3D. Untreated cysts were uniformly dorsal and could be ventralized to floor plate (FP). Retinoic acid posteriorized cysts to cervical levels and induced localize FP formation yielding full patterning along the dorsal/ventral (DV) axis. Correct spatial organization of motor neurons, interneurons, and dorsal interneurons along the DV axis was observed. This system serves as a valuable tool for studying morphogen action in 3D and as a source of patterned spinal cord tissue.

DOI： 10.1016/j.stemcr.2014.09.020

CRISPR-Mediated Genomic Deletion of Sox2 in the Axolotl Shows a Requirement in Spinal Cord Neural Stem Cell Amplification during Tail Regeneration Reviewed

Ji-Feng Fei, Maritta Schuez, Akira Tazaki, Yuka Taniguchi, Kathleen Roensch, Elly M. Tanaka

STEM CELL REPORTS Vol. 3 ( 3 ) page： 444 - 59 2014.9

Language：English Publishing type：Research paper (scientific journal) Publisher：CELL PRESS

The salamander is the only tetrapod that functionally regenerates all cell types of the limb and spinal cord (SC) and thus represents an important regeneration model, but the lack of gene-knockout technology has limited molecular analysis. We compared transcriptional activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPRs) in the knockout of three loci in the axolotl and find that CRISPRs show highly penetrant knockout with less toxic effects compared to TALENs. Deletion of Sox2 in up to 100% of cells yielded viable F0 larvae with normal SC organization and ependymoglial cell marker expression such as GFAP and ZO-1. However, upon tail amputation, neural stem cell proliferation was inhibited, resulting in spinal-cord-specific regeneration failure. In contrast, the mesodermal blastema formed normally. Sox3 expression during development, but not regeneration, most likely allowed embryonic survival and the regeneration-specific phenotype. This analysis represents the first tissue-specific regeneration phenotype from the genomic deletion of a gene in the axolotl.

DOI： 10.1016/j.stemcr.2014.06.018

Progressive Specification Rather than Intercalation of Segments During Limb Regeneration Reviewed International coauthorship

Kathleen Roensch, Akira Tazaki, Osvaldo Chara, Elly M. Tanaka

SCIENCE Vol. 342 ( 6164 ) page： 1375 - 9 2013.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC ADVANCEMENT SCIENCE

An amputated salamander limb regenerates the correct number of segments. Models explaining limb regeneration were largely distinct from those for limb development, despite the presence of common patterning molecules. Intercalation has been an important concept to explain salamander limb regeneration, but clear evidence supporting or refuting this model was lacking. In the intercalation model, the first blastema cells acquire fingertip identity, creating a gap in positional identity that triggers regeneration of the intervening region from the stump. We used HOXA protein analysis and transplantation assays to show that axolotl limb blastema cells acquire positional identity in a proximal-to-distal sequence. Therefore, intercalation is not the primary mechanism for segment formation during limb regeneration in this animal. Patterning in development and regeneration uses similar mechanisms.

DOI： 10.1126/science.1241796

Reprogramming to pluripotency is an ancient trait of vertebrate Oct4 and Pou2 proteins Reviewed International coauthorship

Natalia Tapia, Peter Reinhardt, Annett Duemmler, Guangming Wu, Marcos J. Arauzo-Bravo, Daniel Esch, Boris Greber, Vlad Cojocaru, Cynthia Alexander Rascon, Akira Tazaki, Kevin Kump, Randal Voss, Elly M. Tanaka, Hans R. Schoeler

NATURE COMMUNICATIONS Vol. 3 page： 1279 2012

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

The evolutionary origins of the gene network underlying cellular pluripotency, a central theme in developmental biology, have yet to be elucidated. In mammals, Oct4 is a factor crucial in the reprogramming of differentiated cells into induced pluripotent stem cells. The Oct4 and Pou2 genes evolved from a POU class V gene ancestor, but it is unknown whether pluripotency induced by Oct4 gene activity is a feature specific to mammals or was already present in ancestral vertebrates. Here we report that different vertebrate Pou2 and Oct4 homologues can induce pluripotency in mouse and human fibroblasts and that the inability of zebrafish Pou2 to establish pluripotency is not representative of all Pou2 genes, as medaka Pou2 and axolotl Pou2 are able to reprogram somatic cells into pluripotent cells. Therefore, our results indicate that induction of pluripotency is not a feature specific to mammals, but existed in the Oct4/Pou2 common ancestral vertebrate.

DOI： 10.1038/ncomms2229

Anti-Graying Effects of External and Internal Treatments with Luteolin on Hair in Model Mice Open Access

Machiko Iida, Takumi Kagawa, Ichiro Yajima, Akihito Harusato, Akira Tazaki, Delgama A. S. M. Nishadhi, Nobuhiko Taguchi, Masashi Kato

Antioxidants Vol. 13 ( 12 ) 2024.12

環境騒音から単離した低周波音による血流改善効果の検討

Deng Yuqi, 大神信孝, 童科銘, He Tingchao, 香川匠, 田崎啓, 岩崎成仁, 高橋俊二, 加藤昌志

日本衛生学雑誌 Vol. 79 ( Suppl. ) page： S230 - S230 2024.3

マウス血流に対する低周波騒音の短時間刺激の効果

童科銘, 大神信孝, Deng Yuqi, He Tingchao, 香川匠, 田崎啓, 岩崎成仁, 高橋俊二, 加藤昌志

日本衛生学雑誌 Vol. 79 ( Suppl. ) page： S212 - S212 2024.3

Vascular endothelium as a target tissue for short-term exposure to low-frequency noise that increases cutaneous blood flow. Reviewed International journal Open Access

Yuqi Deng, Nobutaka Ohgami, Takumi Kagawa, Fitri Kurniasari, Dijie Chen, Masashi Kato, Akira Tazaki, Masayo Aoki, Hiroki Katsuta, Keming Tong, Yishuo Gu, Masashi Kato

The Science of the total environment Vol. 851 ( Pt 1 ) page： 158828 - 158828 2022.12

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

Harmful health effects of exposure to low-frequency noise (LFN) defined as noise with frequencies at ≤100 Hz on the circulatory system have been a concern. However, there has been no study on the effects of exposure to LFN on the circulatory system with consideration of its frequencies and decibels. In this study, the effects of short-term exposure to broad-band LFNs and their pure-tone components (pure-tone LFNs) on cutaneous blood flow in the extremities including the hands were investigated. In our fieldwork study, we first sampled some kinds of common broad-band LFNs. Our human study then showed that broad-band LFN with a narrower frequency range more strongly increased cutaneous blood flow than did broad-band LFN with a wider frequency range. Pure-tone LFNs of 70-100 Hz at ≤85 dB(Z), but not pure-tone LFNs exceeding 100 Hz, further increased levels of cutaneous blood flow. Our wavelet-transform spectrum analysis of cutaneous blood flow next revealed that the nitric oxide (NO)-dependent and -independent vascular activities of the vascular endothelium were specifically increased by exposure to pure-tone LFN. Our animal study again indicated that exposure to pure-tone LFN increased cutaneous blood flow in mice with impairments of bilateral inner ears as well as cutaneous blood flow in control mice, suggesting a limited effect of inner ear function on the LFN-mediated increase in cutaneous blood flow. The NO-dependent suppressive effect of pure-tone LFN on cutaneous blood flow was confirmed by inhibition of vascular endothelial activity through intravenous injection of an NO inhibitor in wild-type mice. Taken together, the results of this study demonstrated that the vascular endothelium is a target tissue of LFN and that NO is an effector of the LFN-mediated increase in cutaneous blood flow. Since improvement of peripheral circulation could generally promote human health, short-term exposure to LFN may be beneficial for health.

DOI： 10.1016/j.scitotenv.2022.158828

Potential application of a hydrotalcite-like compound for reduction of toxicity to aquatic organisms via rapid and efficient removal of hydrogen sulfide Reviewed International journal Open Access

Tian Yuan, Kazunori Hashimoto, Akira Tazaki, Masahiro Hasegawa, Fitri Kurniasari, Chihiro Ohta, Masayo Aoki, Nobutaka Ohgami, Masashi Kato

Journal of Environmental Management Vol. 321 page： 115861 - 115861 2022.11

Decreased hearing levels at frequencies for understanding speech in tannery workers exposed to a high level of trivalent chromium in Bangladesh. Reviewed International coauthorship International journal Open Access

Yishuo Gu, Nobutaka Ohgami, M M Aeorangajeb Al Hossain, Akira Tazaki, Tomoyuki Tsuchiyama, Tingchao He, Masayo Aoki, Nazmul Ahsan, Anwarul Azim Akhand, Masashi Kato

Chemosphere Vol. 306 page： 135571 - 135571 2022.11

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

Hexavalent chromium [Cr(VI)], which has a strong corrosive effect, has been reported to cause perforation of the eardrum. Trivalent chromium [Cr(III)] also has a weak corrosive effect. However, there has been no study on the effects of exposure to Cr, either Cr(VI) or Cr(III), on hearing levels in animals or humans. In this study, the effect of Cr(III) exposure on hearing levels was determined in a human study. Then the reproducibility of the results obtained in the human study and the etiology were investigated in an animal study. The mean levels of total chromium (t-Cr) in hair and toenails from 100 Bangladeshi tannery workers were >20-fold and >360-fold higher, respectively, than those in hair and toenails from 49 Bangladeshi non-tannery workers (office workers). Multivariate analysis revealed decreases of hearing levels (DHLs) at 1 k and 4 k Hz, frequencies that are crucial for understanding language, but not at 8 k and 12 k Hz, in the tannery workers. Since >99.99% of t-Cr in the wastewater that the workers were in direct contact with in the tanneries was Cr(III), the epidemiological results suggest Cr(III)-mediated DHLs in the tannery workers. The results of animal experiments in this study further showed that treatment with eardrops but not intraperitoneal injection with the same amount of Cr(III) that tannery workers might be exposed to resulted in DHL with a damaged eardrum in mice. Previous studies suggested that Cr(III) can directly reach the eardrums of tannery workers via droplets in the air. Cr(III) could also reach the eardrum via picking an ear canal with a finger contaminated with tannery wastewater including Cr(III). Taken together, the results of both human and animal studies suggest the risk of DHLs caused by damage of the eardrum through external exposure to Cr(III) via the ear canal.

DOI： 10.1016/j.chemosphere.2022.135571

Significance of platinum distribution to predict platinum resistance in ovarian cancer after platinum treatment in neoadjuvant chemotherapy. Reviewed International journal Open Access

Kaname Uno, Nobuhisa Yoshikawa, Akira Tazaki, Shoko Ohnuma, Kazuhisa Kitami, Shohei Iyoshi, Kazumasa Mogi, Masato Yoshihara, Yoshihiro Koya, Mai Sugiyama, Satoshi Tamauchi, Yoshiki Ikeda, Akira Yokoi, Fumitaka Kikkawa, Masashi Kato, Hiroaki Kajiyama

Scientific reports Vol. 12 ( 1 ) page： 4513 - 4513 2022.3

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

Most patients with ovarian cancer experience recurrence and develop resistance to platinum-based agents. The diagnosis of platinum resistance based on the platinum-free interval is not always accurate and timely in clinical settings. Herein, we used laser ablation inductively coupled plasma mass spectrometry to visualize the platinum distribution in the ovarian cancer tissues at the time of interval debulking surgery after neoadjuvant chemotherapy in 27patients with advanced high-grade serous ovarian cancer. Two distinct patterns of platinum distribution were observed. Type A (n = 16): platinum accumulation at the adjacent stroma but little in the tumor; type B (n = 11): even distribution of platinum throughout the tumor and adjacent stroma. The type A patients treated post-surgery with platinum-based adjuvant chemotherapy showed significantly shorter periods of recurrence after the last platinum-based chemotherapy session (p = 0.020) and were diagnosed with "platinum-resistant recurrence". Moreover, type A was significantly correlated with worse prognosis (p = 0.031). Post-surgery treatment with non-platinum-based chemotherapy could be effective for the patients classified as type A. Our findings indicate that the platinum resistance can be predicted prior to recurrence, based on the platinum distribution; this could contribute to the selection of more appropriate adjuvant chemotherapy, which may lead to improves prognoses.

DOI： 10.1038/s41598-022-08503-7

Oral and Palatal Dentition of Axolotl Arises From a Common Tooth-Competent Zone Along the Ecto-Endodermal Boundary Reviewed International coauthorship

Vladimir Soukup, Akira Tazaki, Yosuke Yamazaki, Anna Pospisilova, Hans-Henning Epperlein, Elly M. Tanaka, Robert Cerny

FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY Vol. 8 page： 622308 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：FRONTIERS MEDIA SA

Vertebrate dentitions arise at various places within the oropharyngeal cavity including the jaws, the palate, or the pharynx. These dentitions develop in a highly organized way, where new tooth germs are progressively added adjacent to the initiator center, the first tooth. At the same time, the places where dentitions develop house the contact zones between the outer ectoderm and the inner endoderm, and this colocalization has instigated various suggestions on the roles of germ layers for tooth initiation and development. Here, we study development of the axolotl dentition, which is a complex of five pairs of tooth fields arranged into the typically tetrapod outer and inner dental arcades. By tracking the expression patterns of odontogenic genes, we reason that teeth of both dental arcades originate from common tooth-competent zones, one present on the mouth roof and one on the mouth floor. Progressive compartmentalization of these zones and a simultaneous addition of new tooth germs distinct for each prospective tooth field subsequently control the final shape and composition of the axolotl dentition. Interestingly, by following the fate of the GFP-labeled oral ectoderm, we further show that, in three out of five tooth field pairs, the first tooth develops right at the ecto-endodermal boundary. Our results thus indicate that a single tooth-competent zone gives rise to both dental arcades of a complex tetrapod dentition. Further, we propose that the ecto-endodermal boundary running through this zone should be accounted for as a potential source of instruction factors instigating the onset of the odontogenic program.

DOI： 10.3389/fcell.2020.622308

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