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Jonathan M.w. Slack - One of the best experts on this subject based on the ideXlab platform.
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Requirement for Wnt and FGF signaling in Xenopus Tadpole Tail regeneration
Developmental Biology, 2008Co-Authors: Jonathan M.w. SlackAbstract:We have investigated the requirement for the FGF and Wnt/beta-catenin pathways for Xenopus Tadpole Tail regeneration. Pathways were modified either by treatment with small molecules or by induction of transgene expression with heat shocks. Regeneration is inhibited by treatment with the FGF inhibitor SU5402, or by activation of a dominant negative FGF receptor, or by activation of expression of the Wnt inhibitor Dkk1. Agents promoting Wnt activity: the small molecule BIO, or a constitutively active form of beta-catenin, led to an increased growth rate. Combination of a Wnt activator with FGF inhibitor suppressed regeneration, while combination of a Wnt inhibitor with a FGF activator allowed regeneration. This suggests that the Wnt activity lies upstream of the FGF activity. Expression of both Wnt and FGF components was inhibited by activation of noggin, suggesting that BMP signalling lies upstream of both Wnt and FGF. The results show that the molecular mechanism of Xenopus Tadpole Tail regeneration is surprisingly similar to that of the Xenopus limb bud and the zebrafish caudal fin, despite the difference of anatomy.
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Requirement for Wnt and FGF signaling in Xenopus Tadpole Tail regeneration
Developmental Biology, 2008Co-Authors: Jonathan M.w. SlackAbstract:We have investigated the requirement for the FGF and Wnt/beta-catenin pathways for Xenopus Tadpole Tail regeneration. Pathways were modified either by treatment with small molecules or by induction of transgene expression with heat shocks. Regeneration is inhibited by treatment with the FGF inhibitor SU5402, or by activation of a dominant negative FGF receptor, or by activation of expression of the Wnt inhibitor Dkk1. Agents promoting Wnt activity: the small molecule BIO, or a constitutively active form of beta-catenin, led to an increased growth rate. Combination of a Wnt activator with FGF inhibitor suppressed regeneration, while combination of a Wnt inhibitor with a FGF activator allowed regeneration. This suggests that the Wnt activity lies upstream of the FGF activity. Expression of both Wnt and FGF components was inhibited by activation of noggin, suggesting that BMP signalling lies upstream of both Wnt and FGF. The results show that the molecular mechanism of Xenopus Tadpole Tail regeneration is surprisingly similar to that of the Xenopus limb bud and the zebrafish caudal fin, despite the difference of anatomy.
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Regeneration of neural crest derivatives in the Xenopus Tadpole Tail
BMC developmental biology, 2007Co-Authors: Gufa Lin, Ying Chen, Jonathan M.w. SlackAbstract:After amputation of the Xenopus Tadpole Tail, a functionally competent new Tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper. Labelling of the spinal cord by electroporation, or by orthotopic grafting of transgenic tissue expressing GFP, shows that no cells emigrate from the spinal cord in the course of regeneration. There is very limited regeneration of the spinal ganglia, but new neurons as well as fibre tracts do appear in the regenerated spinal cord and the regenerated Tail also contains abundant peripheral innervation. The regenerated Tail contains a normal density of melanophores. Cell labelling experiments show that melanophores do not arise from the spinal cord during regeneration, nor from the mesenchymal tissues of the skin, but they do arise by activation and proliferation of pre-existing melanophore precursors. If Tails are prepared lacking melanophores, then the regenerates also lack them. On regeneration there is no induction of a new neural crest similar to that seen in embryonic development. However there is some regeneration of neural crest derivatives. Abundant melanophores are regenerated from unpigmented precursors, and, although spinal ganglia are not regenerated, sufficient sensory systems are produced to enable essential functions to continue.
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control of muscle regeneration in the xenopus Tadpole Tail by pax7
Development, 2006Co-Authors: Ying Che, Jonathan M.w. SlackAbstract:The Tail of the Xenopus Tadpole will regenerate completely after transection. Much of the mass of the regenerate is composed of skeletal muscle, but there has been some uncertainty about the source of the new myofibres. Here, we show that the growing Tail contains many muscle satellite cells. They are active in DNA replication, whereas the myonuclei are not. As in mammals, the satellite cells express pax7. We show that a domain-swapped construct, pax7EnR, can antagonize pax7 function. Transgenic Tadpoles were prepared containing pax7EnR driven by a heat-inducible promoter. When induced, this reduces the proportion of satellite cells formed in the regenerate. A second amputation of the resulting Tails yielded second regenerates containing notochord and spinal cord but little or no muscle. This shows that inhibition of pax7 action does not prevent differentiation of satellite cells to myofibres, but it does prevent their maintenance as a stem cell population.
Enrique Amaya - One of the best experts on this subject based on the ideXlab platform.
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Tadpole Tail regeneration in Xenopus.
Biochemical Society transactions, 2014Co-Authors: Yaoyao Chen, Nick R. Love, Enrique AmayaAbstract:Some organisms have a remarkable ability to heal wounds without scars and to regenerate complex tissues following injury. By gaining a more complete understanding of the biological mechanisms that promote scar-free healing and tissue regeneration, it is hoped that novel treatments that can enhance the healing and regenerative capacity of human patients can be found. In the present article, we briefly examine the genetic, molecular and cellular mechanisms underlying the regeneration of the Xenopus Tadpole Tail.
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Biochemical Determinants of Tissue Regeneration Tadpole Tail regeneration in Xenopus
2014Co-Authors: Yaoyao Chen, Nick R. Love, Enrique AmayaAbstract:Some organisms have a remarkable ability to heal wounds without scars and to regenerate complex tissues following injury. By gaining a more complete understanding of the biological mechanisms that promote scar-free healing and tissue regeneration, it is hoped that novel treatments that can enhance the healing and regenerative capacity of human patients can be found. In the present article, we briefly examine the genetic, molecular and cellular mechanisms underlying the regeneration of the Xenopus Tadpole Tail.
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amputation induced reactive oxygen species are required for successful xenopus Tadpole Tail regeneration
Nature Cell Biology, 2013Co-Authors: Nick R. Love, Yaoyao Che, Robe W Lea, Shoko Ishibashi, Paraskevi Kritsiligkou, Yvette Koh, Jennife L Gallop, Karel Dorey, Enrique AmayaAbstract:Understanding the molecular mechanisms that promote successful tissue regeneration is critical for continued advancements in regenerative medicine. Vertebrate amphibian Tadpoles of the species Xenopus laevis and Xenopus tropicalis have remarkable abilities to regenerate their Tails following amputation 1,2 , through the coordinated activity of numerous growth factor signalling pathways, including the Wnt, Fgf, Bmp, Notch and TGF- pathways 36 . Little is known, however, about the events that act upstream of these signalling pathways following injury. Here, we show that Xenopus Tadpole Tail amputation induces a sustained production of reactive oxygen species (ROS) during Tail regeneration. Lowering ROS levels, using pharmacological or genetic approaches, reduces the level of cell proliferation and impairs Tail regeneration. Genetic rescue experiments restored both ROS production and the initiation of the regenerative response. Sustained increased ROS levels are required for Wnt=-catenin signalling and the activation of one of its main downstream targets, fgf20 (ref. 7), which, in turn, is essential for proper Tail regeneration. These ndings demonstrate that injury-induced ROS production is an
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genome wide analysis of gene expression during xenopus tropicalis Tadpole Tail regeneration
BMC Developmental Biology, 2011Co-Authors: Nick R. Love, Yaoyao Che, Oya Onev, Michael J Gilchris, Lynne Fairclough, Robe W Lea, Timothy J Mohu, Roberto Paredes, Leo A H Zeef, Enrique AmayaAbstract:Background The molecular mechanisms governing vertebrate appendage regeneration remain poorly understood. Uncovering these mechanisms may lead to novel therapies aimed at alleviating human disfigurement and visible loss of function following injury. Here, we explore Tadpole Tail regeneration in Xenopus tropicalis, a diploid frog with a sequenced genome.
Vera Luiza Capelozzi - One of the best experts on this subject based on the ideXlab platform.
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A morphometric and molecular study of the apoptosis observed on Tadpoles' Tail explants under the exposition of triiodothyronine in different homeopathic dilutions.
Homeopathy : the journal of the Faculty of Homeopathy, 2016Co-Authors: José Roberto Pereira Guedes, Solange Carrasco, Cláudia Maris Ferreira, Leoni Villano Bonamin, Claudia Goldenstein-schainberg, Vanessa Martins, Vera Luiza CapelozziAbstract:Background As a therapeutic system, homeopathy is supported by: i) similitude and experimentation in healthy individuals, ii) potentization. A challenge for researchers consists in looking for signals in water (or vehicle) to explain the storage of information in extremely high dilutions and the transfer of such information to the living systems. Anuran amphibian metamorphosis is controlled by thyroid hormones (TH), including the resorption of the Tadpole Tail. Apoptosis is a genetically regulated form of cell death that can be triggered by various extracellular and intracellular stimuli resulting in coordinated activation of a family of cysteine proteases called caspases. Methods This study was blind and randomized. It performed in three stages: I) the identification of the most effective T3 homeopathic dilution to induce apoptotic reactions in Rana (Lithobates) catesbeianus Tadpole Tail explants stimulated by T3 in substantial, II) study of different controls and III) detection in explants under the action of the most effective dilution of T3, as established in Stage I. Results There was no statistically significant difference between Tail macroscopic dimensions between the groups. T3 10cH decreased the expression of caspase 3/7 mRNA, in explants treated with T3 20 nM. Conclusion The present experiment is in agreement with the hypothesis that T3, at a 10cH homeopathic dilution, changes the metamorphosis molecular network.
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triiodothyronine diluted according homeopathic techniques modifies the programmed cell death of Tadpole Tail s explants
International Journal of High Dilution Research, 2011Co-Authors: José Roberto Pereira Guedes, Solange Carrasco, Leoni Villano Bonamin, Claudia Maris Ferreira Mosterio, Welluma Souza, Claudia Goldenstein Schainberg, Edwin Roger Parracuentas, Vera Luiza CapelozziAbstract:High Dilution is a solution beyond the Avogadro limits that, in the dependence of the applied succussion elicits a suppressive or a stimulant effect on a living cell, with a consequent generation of an oscillatory doseeffect curve. According to Bonamin et al. [1], “Perhaps, the most enigmatic feature regarding the properties of high dilutions is the non-linearity of their effects. In several studies employing in vivo and ex vivo models, especially involving iso-endopathy, an oscillatory potency-effect curve has appeared. The first observations were initially considered as artifacts, but the repetition of this pattern in different studies involving completely different experimental models, in times and places equally different, points out to the existence of a property intrinsic to dynamized systems.” The entire process of anuran amphibian metamorphosis is under thyroid hormones control, included the complete resorption of the Tadpole Tail. In the present study, we had successfully established a protocol model to culture Rana catesbeiana Tadpoles’ Tail tips in vitro. A random and blind study was performed, with the intent to prove that T3 5.10 -24 M (10 cH) modifies the apoptosis induction of T3 100 nM in explants of Rana catesbeiana Tadpoles’ Tail. 60 explants were distributed in three ways: Group A: without T3 action, at pharmacological and HD dose; Group B (test): under the action of T3 100 nM and treated with T3 10 cH (HD); Group C (control): under the action of T3 100 nM and treated with ethanol 70% unsuccussed. After 96 hours of tissue culture, the mean of initial and final area (1.05 vs. 0.98 cm2) and apoptotic index of the explants from Group A were with minimal difference range and for this reason it wasn’t included in the statistical study. In order to identify significant differences in the area and in the apoptotic index of the remainder explants of the 2 groups, B (test) and C (control), we used a student t-test. However, the mean initial and final explants’ area from test and control groups were respectively 1.09 vs. 0.22 cm and 1.00 cm vs. 0.24 cm, with a mean reduction of 0.87 cm2 and 0.76 cm2, but this difference didn’t achieve statistical significance (p>0.05). In contrast, apoptosis index was significantly higher in test than in control group 11.7 vs. 7.9 (p<0.05), with is confirmed at the table 1.
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Ultra high dilution of triiodothyronine modifies cellular apoptosis in Rana catesbeiana Tadpole Tail in vitro.
Homeopathy : the journal of the Faculty of Homeopathy, 2011Co-Authors: José Roberto Pereira Guedes, Solange Carrasco, Cláudia Maris Ferreira, Leoni Villano Bonamin, W. Souza, Claudia Goldenstein-schainberg, Edwin Roger Parra, Vera Luiza CapelozziAbstract:Background Ultra High Dilutions (UHD) are diluted beyond the Avogadro limit with dynamization (dilution with succussion). The process of anuran amphibian metamorphosis is controlled by thyroid hormones, including the resorption of the Tadpole Tail. Methods A randomized and blinded study was performed to investigate the influence of triiodothyronine (T3) 5 · 10−24 M (10cH) on apoptosis induced by T3 100 nM in Rana catesbeiana Tadpoles’ Tail tips, in vitro. Explants were randomized to three groups: control: no T3 in pharmacological or UHD dose; test: T3 100 nM and challenged with T3 10cH (UHD); positive control: T3 100 nM, treated with unsuccussed ethanol. The apoptotic index and the area of explants of test and control groups at the first and final day of the experiment were compared by t-test. Results There was no difference in Tail tip area between test and control groups, but a significantly higher (p Conclusion This data suggest that T3 10cH modifies the effect of T3 at pharmacological dose, opening new perspectives for further studies and investigation of the dose–effect curve.
Nick R. Love - One of the best experts on this subject based on the ideXlab platform.
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Tadpole Tail regeneration in Xenopus.
Biochemical Society transactions, 2014Co-Authors: Yaoyao Chen, Nick R. Love, Enrique AmayaAbstract:Some organisms have a remarkable ability to heal wounds without scars and to regenerate complex tissues following injury. By gaining a more complete understanding of the biological mechanisms that promote scar-free healing and tissue regeneration, it is hoped that novel treatments that can enhance the healing and regenerative capacity of human patients can be found. In the present article, we briefly examine the genetic, molecular and cellular mechanisms underlying the regeneration of the Xenopus Tadpole Tail.
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Biochemical Determinants of Tissue Regeneration Tadpole Tail regeneration in Xenopus
2014Co-Authors: Yaoyao Chen, Nick R. Love, Enrique AmayaAbstract:Some organisms have a remarkable ability to heal wounds without scars and to regenerate complex tissues following injury. By gaining a more complete understanding of the biological mechanisms that promote scar-free healing and tissue regeneration, it is hoped that novel treatments that can enhance the healing and regenerative capacity of human patients can be found. In the present article, we briefly examine the genetic, molecular and cellular mechanisms underlying the regeneration of the Xenopus Tadpole Tail.
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amputation induced reactive oxygen species are required for successful xenopus Tadpole Tail regeneration
Nature Cell Biology, 2013Co-Authors: Nick R. Love, Yaoyao Che, Robe W Lea, Shoko Ishibashi, Paraskevi Kritsiligkou, Yvette Koh, Jennife L Gallop, Karel Dorey, Enrique AmayaAbstract:Understanding the molecular mechanisms that promote successful tissue regeneration is critical for continued advancements in regenerative medicine. Vertebrate amphibian Tadpoles of the species Xenopus laevis and Xenopus tropicalis have remarkable abilities to regenerate their Tails following amputation 1,2 , through the coordinated activity of numerous growth factor signalling pathways, including the Wnt, Fgf, Bmp, Notch and TGF- pathways 36 . Little is known, however, about the events that act upstream of these signalling pathways following injury. Here, we show that Xenopus Tadpole Tail amputation induces a sustained production of reactive oxygen species (ROS) during Tail regeneration. Lowering ROS levels, using pharmacological or genetic approaches, reduces the level of cell proliferation and impairs Tail regeneration. Genetic rescue experiments restored both ROS production and the initiation of the regenerative response. Sustained increased ROS levels are required for Wnt=-catenin signalling and the activation of one of its main downstream targets, fgf20 (ref. 7), which, in turn, is essential for proper Tail regeneration. These ndings demonstrate that injury-induced ROS production is an
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genome wide analysis of gene expression during xenopus tropicalis Tadpole Tail regeneration
BMC Developmental Biology, 2011Co-Authors: Nick R. Love, Yaoyao Che, Oya Onev, Michael J Gilchris, Lynne Fairclough, Robe W Lea, Timothy J Mohu, Roberto Paredes, Leo A H Zeef, Enrique AmayaAbstract:Background The molecular mechanisms governing vertebrate appendage regeneration remain poorly understood. Uncovering these mechanisms may lead to novel therapies aimed at alleviating human disfigurement and visible loss of function following injury. Here, we explore Tadpole Tail regeneration in Xenopus tropicalis, a diploid frog with a sequenced genome.
Yoshio Yaoita - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms of Tail resorption during anuran metamorphosis
Biomolecular concepts, 2017Co-Authors: Yuya Nakai, Keisuke Nakajima, Yoshio YaoitaAbstract:Amphibian metamorphosis has historically attracted a good deal of scientific attention owing to its dramatic nature and easy observability. However, the genetic mechanisms of amphibian metamorphosis have not been thoroughly examined using modern techniques such as gene cloning, DNA sequencing, polymerase chain reaction or genomic editing. Here, we review the current state of knowledge regarding molecular mechanisms underlying Tadpole Tail resorption.
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Dual mechanisms governing muscle cell death in Tadpole Tail during amphibian metamorphosis
Developmental dynamics : an official publication of the American Association of Anatomists, 2003Co-Authors: Keisuke Nakajima, Yoshio YaoitaAbstract:The Tadpole Tail, which is twice as long as the body, is induced to resorb completely by thyroid hormone within several days during the anuran metamorphosis. To investigate the underlying mechanism, we undertook two approaches. First, we examined the effect of dominant-negative thyroid hormone receptor (DNTR) on muscle cell death in vitro. The overexpression of DNTR suppressed the death of a Tail-derived myoblastic cell line induced by thyroid hormone. Second, Tadpole Tails were injected with a reporter gene and the DNTR expression construct, and the reporter gene expression in muscle cells was followed during the spontaneous metamorphosis. DNTR overexpression inhibited a decrease of the reporter gene expression that began at stage 57 in the control Tadpoles but only delayed massive muscle cell death at stage 63 when Tails shrink very rapidly. Some remained even a few weeks after the metamorphosis, although most DNTR-overexpressing cells died by the end of the metamorphosis. These results led us to propose that thyroid hormone induces the suicide of muscle cells (the cell-autonomous death) in the Tail between stage 57 and 62 and that both the murder and suicide mechanisms execute muscle cell death in stage 62-64 to remove muscle promptly and completely.
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induction of apoptosis and cpp32 expression by thyroid hormone in a myoblastic cell line derived from Tadpole Tail
Journal of Biological Chemistry, 1997Co-Authors: Yoshio Yaoita, Keisuke NakajimaAbstract:Abstract During amphibian metamorphosis, the Tail and gills that are useful in aquatic life but inappropriate for terrestrial activity are induced to degenerate completely in several days by endogenous thyroid hormone (TH). The dramatic resorption of the Tadpole Tail has attracted a good deal of attention as an experimental system of cell death, but the mechanism has not been well characterized. To facilitate in vitro analysis, we have established a myoblast cell line (XLT-15) derived from the Xenopus laevis Tadpole Tail. This cultured cell line died in response to TH and exhibited positive TUNEL reaction and internucleosomal DNA cleavage. Simultaneously, expression of the Xenopus CPP32/apopain/Yama gene was up-regulated by TH in the cell line as it is in regressing Tadpole Tail, whereas interleukin-1β-converting enzyme (ICE) mRNA is around 1 copy/cell in Tail and undetectable in XLT-15 cells. A CPP32/apopain/Yama inhibitor (acetyl-Asp-Glu-Val-Asp-aldehyde) prevented TH-induced apoptosis of XLT-15 cells, but an ICE inhibitor (acetyl-Tyr-Val-Ala-Asp-aldehyde) did not. These results suggested that an increase of CPP32/apopain/Yama gene expression is involved in TH-dependent apoptosis of XLT-15 and Tadpole Tail resorption during metamorphosis.
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INDUCTION OF APOPTOSIS AND CPP32 EXPRESSION BY THYROID HORMONE IN A MYOBLASTIC CELL LINE DERIVED FROM Tadpole Tail
The Journal of biological chemistry, 1997Co-Authors: Yoshio Yaoita, Keisuke NakajimaAbstract:During amphibian metamorphosis, the Tail and gills that are useful in aquatic life but inappropriate for terrestrial activity are induced to degenerate completely in several days by endogenous thyroid hormone (TH). The dramatic resorption of the Tadpole Tail has attracted a good deal of attention as an experimental system of cell death, but the mechanism has not been well characterized. To facilitate in vitro analysis, we have established a myoblast cell line (XLT-15) derived from the Xenopus laevis Tadpole Tail. This cultured cell line died in response to TH and exhibited positive TUNEL reaction and internucleosomal DNA cleavage. Simultaneously, expression of the Xenopus CPP32/apopain/Yama gene was up-regulated by TH in the cell line as it is in regressing Tadpole Tail, whereas interleukin-1beta-converting enzyme (ICE) mRNA is around 1 copy/cell in Tail and undetectable in XLT-15 cells. A CPP32/apopain/Yama inhibitor (acetyl-Asp-Glu-Val-Asp-aldehyde) prevented TH-induced apoptosis of XLT-15 cells, but an ICE inhibitor (acetyl-Tyr-Val-Ala-Asp-aldehyde) did not. These results suggested that an increase of CPP32/apopain/Yama gene expression is involved in TH-dependent apoptosis of XLT-15 and Tadpole Tail resorption during metamorphosis.
