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Kha CX, Nava I, Tseng KAS. V-ATPase Regulates Retinal Progenitor Cell Proliferation During Eye Regrowth in Xenopus. J Ocul Pharmacol Ther 2023; 39:499-508. [PMID: 36867156 PMCID: PMC10616942 DOI: 10.1089/jop.2022.0085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/29/2022] [Indexed: 03/04/2023] Open
Abstract
Purpose: The induction of retinal progenitor cell (RPC) proliferation is a strategy that holds promise for alleviating retinal degeneration. However, the mechanisms that can stimulate RPC proliferation during repair remain unclear. Xenopus tailbud embryos successfully regrow functional eyes within 5 days after ablation, and this process requires increased RPC proliferation. This model facilitates identification of mechanisms that can drive in vivo reparative RPC proliferation. This study assesses the role of the essential H+ pump, V-ATPase, in promoting stem cell proliferation. Methods: Pharmacological and molecular loss of function studies were performed to determine the requirement for V-ATPase during embryonic eye regrowth. The resultant eye phenotypes were examined using histology and antibody markers. Misexpression of a yeast H+ pump was used to test whether the requirement for V-ATPase in regrowth is dependent on its H+ pump function. Results: V-ATPase inhibition blocked eye regrowth. Regrowth-incompetent eyes resulting from V-ATPase inhibition contained the normal complement of tissues but were much smaller. V-ATPase inhibition caused a significant reduction in reparative RPC proliferation but did not alter differentiation and patterning. Modulation of V-ATPase activity did not affect apoptosis, a process known to be required for eye regrowth. Finally, increasing H+ pump activity was sufficient to induce regrowth. Conclusions: V-ATPase is required for eye regrowth. These results reveal a key role for V-ATPase in activating regenerative RPC proliferation and expansion during successful eye regrowth.
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Affiliation(s)
- Cindy X. Kha
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
| | - Iris Nava
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
| | - Kelly Ai-Sun Tseng
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
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2
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Blackiston D, Lederer E, Kriegman S, Garnier S, Bongard J, Levin M. A cellular platform for the development of synthetic living machines. Sci Robot 2021; 6:6/52/eabf1571. [PMID: 34043553 DOI: 10.1126/scirobotics.abf1571] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
Robot swarms have, to date, been constructed from artificial materials. Motile biological constructs have been created from muscle cells grown on precisely shaped scaffolds. However, the exploitation of emergent self-organization and functional plasticity into a self-directed living machine has remained a major challenge. We report here a method for generation of in vitro biological robots from frog (Xenopus laevis) cells. These xenobots exhibit coordinated locomotion via cilia present on their surface. These cilia arise through normal tissue patterning and do not require complicated construction methods or genomic editing, making production amenable to high-throughput projects. The biological robots arise by cellular self-organization and do not require scaffolds or microprinting; the amphibian cells are highly amenable to surgical, genetic, chemical, and optical stimulation during the self-assembly process. We show that the xenobots can navigate aqueous environments in diverse ways, heal after damage, and show emergent group behaviors. We constructed a computational model to predict useful collective behaviors that can be elicited from a xenobot swarm. In addition, we provide proof of principle for a writable molecular memory using a photoconvertible protein that can record exposure to a specific wavelength of light. Together, these results introduce a platform that can be used to study many aspects of self-assembly, swarm behavior, and synthetic bioengineering, as well as provide versatile, soft-body living machines for numerous practical applications in biomedicine and the environment.
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Affiliation(s)
| | - Emma Lederer
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Sam Kriegman
- Department of Computer Science, University of Vermont, Burlington, VT 05405, USA
| | - Simon Garnier
- Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Joshua Bongard
- Department of Computer Science, University of Vermont, Burlington, VT 05405, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA. .,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
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3
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Pai VP, Cervera J, Mafe S, Willocq V, Lederer EK, Levin M. HCN2 Channel-Induced Rescue of Brain Teratogenesis via Local and Long-Range Bioelectric Repair. Front Cell Neurosci 2020; 14:136. [PMID: 32528251 PMCID: PMC7264377 DOI: 10.3389/fncel.2020.00136] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/22/2020] [Indexed: 12/21/2022] Open
Abstract
Embryonic exposure to the teratogen nicotine results in brain defects, by disrupting endogenous spatial pre patterns necessary for normal brain size and patterning. Extending prior work in Xenopus laevis that showed that misexpression of ion channels can rescue morphogenesis, we demonstrate and characterize a novel aspect of developmental bioelectricity: channel-dependent repair signals propagate long-range across the embryo. We show that distal HCN2 channel misexpression and distal transplants of HCN2-expressing tissue, non-cell-autonomously reverse profound defects, rescuing brain anatomy, gene expression, and learning. Moreover, such rescue can be induced by small-molecule HCN2 channel activators, even with delayed treatment initiation. We present a simple, versatile computational model of bioelectrical signaling upstream of key patterning genes such as OTX2 and XBF1, which predicts long-range repair induced by ion channel activity, and experimentally validate the predictions of this model. Our results and quantitative model identify a powerful morphogenetic control mechanism that could be targeted by future regenerative medicine exploiting ion channel modulating drugs approved for human use.
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Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Javier Cervera
- Departament de Termodinamica, Facultat de Fisica, Universitat de Valencia, Burjassot, Spain
| | - Salvador Mafe
- Departament de Termodinamica, Facultat de Fisica, Universitat de Valencia, Burjassot, Spain
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Emma K Lederer
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
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Kha CX, Guerin DJ, Tseng KAS. Studying In Vivo Retinal Progenitor Cell Proliferation in Xenopus laevis. Methods Mol Biol 2019; 2092:19-33. [PMID: 31786778 DOI: 10.1007/978-1-0716-0175-4_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
The efficient generation and maintenance of retinal progenitor cells (RPCs) are key goals needed for developing strategies for productive eye repair. Although vertebrate eye development and retinogenesis are well characterized, the mechanisms that can initiate RPC proliferation following injury-induced regrowth and repair remain unknown. This is partly because endogenous RPC proliferation typically occurs during embryogenesis while studies of retinal regeneration have largely utilized adult (or mature) models. We found that embryos of the African clawed frog, Xenopus laevis, successfully regrew functional eyes after ablation. The initiation of regrowth induced a robust RPC proliferative response with a concomitant delay of the endogenous RPC differentiation program. During eye regrowth, overall embryonic development proceeded normally. Here, we provide a protocol to study regrowth-dependent RPC proliferation in vivo. This system represents a robust and low-cost strategy to rapidly define fundamental mechanisms that regulate regrowth-initiated RPC proliferation, which will facilitate progress in identifying promising strategies for productive eye repair.
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Affiliation(s)
- Cindy X Kha
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Dylan J Guerin
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Kelly Ai-Sun Tseng
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA.
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5
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Blackiston DJ, Vien K, Levin M. Serotonergic stimulation induces nerve growth and promotes visual learning via posterior eye grafts in a vertebrate model of induced sensory plasticity. NPJ Regen Med 2017; 2:8. [PMID: 29302344 PMCID: PMC5665622 DOI: 10.1038/s41536-017-0012-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/03/2017] [Accepted: 02/05/2017] [Indexed: 12/27/2022] Open
Abstract
The major goal of regenerative medicine is to repair damaged tissues and organ systems, thereby restoring their native functions in the host. Control of innervation by re-grown or implanted structures, and integration of the nascent nerves into behavioral/cognitive programs of the host, remains a critical barrier. In the case of sensory organs, this is particularly true, as afferent neurons must form connections with the host to communicate auditory, visual, and tactile information. Xenopus embryos and tadpoles are powerful models for such studies, as grafting techniques allow for the creation of eyes and other sensory structures along the body axis, and the behavior of the resulting organism can be quantitatively analyzed. Previous work has demonstrated that ectopic eyes could be grafted in blinded tadpoles, allowing some of the animals to learn in a simple light-preference assay. Here, we show that it is possible to improve the efficiency of the process in the context of a novel image-forming vision assay, using a drug already approved for human use. Innervation of the host by ectopic eyes can be increased by targeting a serotonergic signaling mechanism: grafts treated with a 5-HT1B/D agonist strongly innervate the recipient compared with untreated grafts, without large-scale disruption of the host nervous system. Blind animals possessing eye grafts with the augmented innervation demonstrate increased performance over untreated siblings in wavelength-based learning assays. Furthermore, treated animals also exhibit enhanced visual pattern recognition, suggesting that the increased innervation in response to 5-HT1B/D activation leads to enhanced functional integration of the ectopic organ with the host central nervous system and behavioral programs. These data establish a model system and reveal a new roadmap using small molecule neurotransmitter drugs to augment innervation, integration, and function of transplanted heterologous organs in regenerative medicine. A migraine drug that modulates neurotransmitter signaling can boost the neural connections of eyes grafted onto tadpoles to enhance vision. Michael Levin and colleagues from Tufts University in Medford, MA, USA, built on previous work from their lab showing that eyes could be attached along the body axis of blind tadpoles, allowing the developing frogs to distinguish between light and dark. Following the surgery, the researchers have now added the drug zolmitriptan, an activator of serotonin receptors, and the tadpoles formed many more neural connections that sprouted from their ectopic eyes. These animals performed better in visual-learning and pattern-movement tests than control tadpoles that did not get the drug. The findings suggest that drugs used to treat neurological and psychiatric diseases could be repurposed to augment the innervation, integration, and function of organs transplanted in regenerative therapies.
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Affiliation(s)
- Douglas J Blackiston
- Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
| | - Khanh Vien
- Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
| | - Michael Levin
- Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
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6
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Using hydrogels in microscopy: A tutorial. Micron 2016; 84:7-16. [DOI: 10.1016/j.micron.2016.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 01/13/2023]
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7
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Abdul-Wajid S, Morales-Diaz H, Khairallah SM, Smith WC. T-type Calcium Channel Regulation of Neural Tube Closure and EphrinA/EPHA Expression. Cell Rep 2015; 13:829-839. [PMID: 26489462 DOI: 10.1016/j.celrep.2015.09.035] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 08/06/2015] [Accepted: 09/11/2015] [Indexed: 10/22/2022] Open
Abstract
A major class of human birth defects arise from aberrations during neural tube closure (NTC). We report on a NTC signaling pathway requiring T-type calcium channels (TTCCs) that is conserved between primitive chordates (Ciona) and Xenopus. With loss of TTCCs, there is a failure to seal the anterior neural folds. Accompanying loss of TTCCs is an upregulation of EphrinA effectors. Ephrin signaling is known to be important in NTC, and ephrins can affect both cell adhesion and repulsion. In Ciona, ephrinA-d expression is downregulated at the end of neurulation, whereas, with loss of TTCC, ephrinA-d remains elevated. Accordingly, overexpression of ephrinA-d phenocopied TTCC loss of function, while overexpression of a dominant-negative Ephrin receptor was able to rescue NTC in a Ciona TTCC mutant. We hypothesize that signaling through TTCCs is necessary for proper anterior NTC through downregulation of ephrins, and possibly elimination of a repulsive signal.
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Affiliation(s)
- Sarah Abdul-Wajid
- Department of Molecular, Cell and Developmental Biology, and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Heidi Morales-Diaz
- Department of Molecular, Cell and Developmental Biology, and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Stephanie M Khairallah
- Department of Molecular, Cell and Developmental Biology, and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - William C Smith
- Department of Molecular, Cell and Developmental Biology, and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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8
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Pai VP, Lemire JM, Paré JF, Lin G, Chen Y, Levin M. Endogenous gradients of resting potential instructively pattern embryonic neural tissue via Notch signaling and regulation of proliferation. J Neurosci 2015; 35:4366-85. [PMID: 25762681 PMCID: PMC4355204 DOI: 10.1523/jneurosci.1877-14.2015] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 12/21/2014] [Accepted: 01/14/2015] [Indexed: 12/26/2022] Open
Abstract
Biophysical forces play important roles throughout embryogenesis, but the roles of spatial differences in cellular resting potentials during large-scale brain morphogenesis remain unknown. Here, we implicate endogenous bioelectricity as an instructive factor during brain patterning in Xenopus laevis. Early frog embryos exhibit a characteristic hyperpolarization of cells lining the neural tube; disruption of this spatial gradient of the transmembrane potential (Vmem) diminishes or eliminates the expression of early brain markers, and causes anatomical mispatterning of the brain, including absent or malformed regions. This effect is mediated by voltage-gated calcium signaling and gap-junctional communication. In addition to cell-autonomous effects, we show that hyperpolarization of transmembrane potential (Vmem) in ventral cells outside the brain induces upregulation of neural cell proliferation at long range. Misexpression of the constitutively active form of Notch, a suppressor of neural induction, impairs the normal hyperpolarization pattern and neural patterning; forced hyperpolarization by misexpression of specific ion channels rescues brain defects induced by activated Notch signaling. Strikingly, hyperpolarizing posterior or ventral cells induces the production of ectopic neural tissue considerably outside the neural field. The hyperpolarization signal also synergizes with canonical reprogramming factors (POU and HB4), directing undifferentiated cells toward neural fate in vivo. These data identify a new functional role for bioelectric signaling in brain patterning, reveal interactions between Vmem and key biochemical pathways (Notch and Ca(2+) signaling) as the molecular mechanism by which spatial differences of Vmem regulate organogenesis of the vertebrate brain, and suggest voltage modulation as a tractable strategy for intervention in certain classes of birth defects.
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Affiliation(s)
- Vaibhav P Pai
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts 02155-4243 and
| | - Joan M Lemire
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts 02155-4243 and
| | - Jean-François Paré
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts 02155-4243 and
| | - Gufa Lin
- Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota 55455
| | - Ying Chen
- Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota 55455
| | - Michael Levin
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts 02155-4243 and
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9
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Blackiston DJ, Anderson GM, Rahman N, Bieck C, Levin M. A novel method for inducing nerve growth via modulation of host resting potential: gap junction-mediated and serotonergic signaling mechanisms. Neurotherapeutics 2015; 12:170-84. [PMID: 25449797 PMCID: PMC4322068 DOI: 10.1007/s13311-014-0317-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A major goal of regenerative medicine is to restore the function of damaged or missing organs through the implantation of bioengineered or donor-derived components. It is necessary to understand the signals and cues necessary for implanted structures to innervate the host, as organs devoid of neural connections provide little benefit to the patient. While developmental studies have identified neuronal pathfinding molecules required for proper patterning during embryogenesis, strategies to initiate innervation in structures transplanted at later times or alternate locations remain limited. Recent work has identified membrane resting potential of nerves as a key regulator of growth cone extension or arrest. Here, we identify a novel role of bioelectricity in the generation of axon guidance cues, showing that neurons read the electric topography of surrounding cells, and demonstrate these cues can be leveraged to initiate sensory organ transplant innervation. Grafts of fluorescently labeled embryological eye primordia were used to produce ectopic eyes in Xenopus laevis tadpoles. Depolarization of host tissues through anion channel activation or other means led to a striking hyperinnervation of the body by these ectopic eyes. A screen of possible transduction mechanisms identified serotonergic signaling to be essential for hyperinnervation to occur, and our molecular data suggest a possible model of bioelectrical control of the distribution of neurotransmitters that guides nerve growth. Together, these results identify the molecular components of bioelectrical signaling among cells that regulates axon guidance, and suggest novel biomedical and bioengineering strategies for triggering neuronal outgrowth using ion channel drugs already approved for human use.
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Affiliation(s)
- Douglas J. Blackiston
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
| | - George M. Anderson
- Yale Child Study Center and Department of Laboratory Medicine, Yale University School of Medicine, 230 S. Frontage Rd., New Haven, CT 06519 USA
| | - Nikita Rahman
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
| | - Clara Bieck
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
| | - Michael Levin
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155 USA
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Neurally Derived Tissues in Xenopus laevis Embryos Exhibit a Consistent Bioelectrical Left-Right Asymmetry. Stem Cells Int 2012; 2012:353491. [PMID: 23346115 PMCID: PMC3544345 DOI: 10.1155/2012/353491] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/07/2012] [Indexed: 11/18/2022] Open
Abstract
Consistent left-right asymmetry in organ morphogenesis is a fascinating aspect of bilaterian development. Although embryonic patterning of asymmetric viscera, heart, and brain is beginning to be understood, less is known about possible subtle asymmetries present in anatomically identical paired structures. We investigated two important developmental events: physiological controls of eye development and specification of neural crest derivatives, in Xenopus laevis embryos. We found that the striking hyperpolarization of transmembrane potential (Vmem) demarcating eye induction usually occurs in the right eye field first. This asymmetry is randomized by perturbing visceral left-right patterning, suggesting that eye asymmetry is linked to mechanisms establishing primary laterality. Bilateral misexpression of a depolarizing channel mRNA affects primarily the right eye, revealing an additional functional asymmetry in the control of eye patterning by Vmem. The ATP-sensitive K+ channel subunit transcript, SUR1, is asymmetrically expressed in the eye primordia, thus being a good candidate for the observed physiological asymmetries. Such subtle asymmetries are not only seen in the eye: consistent asymmetry was also observed in the migration of differentiated melanocytes on the left and right sides. These data suggest that even anatomically symmetrical structures may possess subtle but consistent laterality and interact with other developmental left-right patterning pathways.
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Kurth T, Weiche S, Vorkel D, Kretschmar S, Menge A. Histology of plastic embedded amphibian embryos and larvae. Genesis 2011; 50:235-50. [DOI: 10.1002/dvg.20821] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 10/27/2011] [Accepted: 10/28/2011] [Indexed: 12/27/2022]
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12
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Vandenberg LN, Pennarola BW, Levin M. Low frequency vibrations disrupt left-right patterning in the Xenopus embryo. PLoS One 2011; 6:e23306. [PMID: 21826245 PMCID: PMC3149648 DOI: 10.1371/journal.pone.0023306] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/15/2011] [Indexed: 11/19/2022] Open
Abstract
The development of consistent left-right (LR) asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure to several low frequencies induced specific randomization of three internal organs (heterotaxia). Investigating one frequency (7 Hz), we found two discrete periods of sensitivity to vibration; during the first period, vibration affected the same LR pathway as nocodazole, while during the second period, vibration affected the integrity of the epithelial barrier; both are required for normal LR patterning. Our results indicate that low frequency vibrations disrupt two steps in the early LR pathway: the orientation of the LR axis with the other two axes, and the amplification/restriction of downstream LR signals to asymmetric organs.
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Affiliation(s)
- Laura N. Vandenberg
- Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts, United States of America
- Biology Department, Tufts University, Medford, Massachusetts, United States of America
| | - Brian W. Pennarola
- Biology Department, Tufts University, Medford, Massachusetts, United States of America
| | - Michael Levin
- Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts, United States of America
- Biology Department, Tufts University, Medford, Massachusetts, United States of America
- * E-mail:
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