1
|
Asai R, Sinha S, Prakash VN, Mikawa T. Cellular flows initiate left-right patterning prior to laterality gene expression in amniotes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.21.590437. [PMID: 38712212 PMCID: PMC11071402 DOI: 10.1101/2024.04.21.590437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
A bilateral body plan is predominant throughout the animal kingdom. Bilaterality of amniote embryos becomes recognizable as midline morphogenesis begins at gastrulation, bisecting an embryonic field into the left and right sides. Soon after, left-right asymmetry also starts. While a series of laterality genes expressed after the left-right compartmentalization has been extensively studied, the laterality patterning prior to and during midline morphogenesis has remained unclear. Here, through a biophysical quantification in a high spatial and temporal resolution, applied to a chick model system, we show that a large-scale bilateral counter-rotating cell flow, termed as 'polonaise movements', display left-right asymmetries in early gastrulation. This cell movement starts prior to the formation of the primitive streak, which is the earliest midline structure, and earlier than expression of laterality genes. The cell flow speed and vorticity unravel the location and timing of the left-right asymmetries. The bilateral cell flow exhibited a Left side asymmetry at the beginning, but a transition towards Right dominance. Mitotic arrest that diminishes primitive streak formation resulted in changes in the bilateral flow pattern, but the Right dominance persisted. Our data indicate that the left-right asymmetry in amniote gastrula becomes detectable prior to the point when the asymmetric regulation of the laterality signals at the node leads to the left-right patterning. More broadly, our results suggest that physical processes can play an unexpected but significant role in influencing left-right laterality during embryonic development.
Collapse
Affiliation(s)
- Rieko Asai
- Cardiovascular Research Institute, University of California, San Francisco. San Francisco, California 94158, USA
- Department of Marine Biology and Ecology, University of Miami, Miami, Florida 33149, USA
| | - Shubham Sinha
- Department of Physics, University of Miami, Coral Gables, Florida 33146, USA
| | - Vivek N. Prakash
- Department of Physics, University of Miami, Coral Gables, Florida 33146, USA
- Department of Biology, University of Miami, Coral Gables, Florida 33146, USA
- Department of Marine Biology and Ecology, University of Miami, Miami, Florida 33149, USA
| | - Takashi Mikawa
- Cardiovascular Research Institute, University of California, San Francisco. San Francisco, California 94158, USA
| |
Collapse
|
2
|
McMillen P, Levin M. Collective intelligence: A unifying concept for integrating biology across scales and substrates. Commun Biol 2024; 7:378. [PMID: 38548821 PMCID: PMC10978875 DOI: 10.1038/s42003-024-06037-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 03/11/2024] [Indexed: 04/01/2024] Open
Abstract
A defining feature of biology is the use of a multiscale architecture, ranging from molecular networks to cells, tissues, organs, whole bodies, and swarms. Crucially however, biology is not only nested structurally, but also functionally: each level is able to solve problems in distinct problem spaces, such as physiological, morphological, and behavioral state space. Percolating adaptive functionality from one level of competent subunits to a higher functional level of organization requires collective dynamics: multiple components must work together to achieve specific outcomes. Here we overview a number of biological examples at different scales which highlight the ability of cellular material to make decisions that implement cooperation toward specific homeodynamic endpoints, and implement collective intelligence by solving problems at the cell, tissue, and whole-organism levels. We explore the hypothesis that collective intelligence is not only the province of groups of animals, and that an important symmetry exists between the behavioral science of swarms and the competencies of cells and other biological systems at different scales. We then briefly outline the implications of this approach, and the possible impact of tools from the field of diverse intelligence for regenerative medicine and synthetic bioengineering.
Collapse
Affiliation(s)
- Patrick McMillen
- Department of Biology, Tufts University, Medford, MA, 02155, USA
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Michael Levin
- Department of Biology, Tufts University, Medford, MA, 02155, USA.
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA.
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.
| |
Collapse
|
3
|
Tung A, Sperry MM, Clawson W, Pavuluri A, Bulatao S, Yue M, Flores RM, Pai VP, McMillen P, Kuchling F, Levin M. Embryos assist morphogenesis of others through calcium and ATP signaling mechanisms in collective teratogen resistance. Nat Commun 2024; 15:535. [PMID: 38233424 PMCID: PMC10794468 DOI: 10.1038/s41467-023-44522-2] [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] [Received: 06/22/2023] [Accepted: 12/17/2023] [Indexed: 01/19/2024] Open
Abstract
Information for organismal patterning can come from a variety of sources. We investigate the possibility that instructive influences for normal embryonic development are provided not only at the level of cells within the embryo, but also via interactions between embryos. To explore this, we challenge groups of embryos with disruptors of normal development while varying group size. Here, we show that Xenopus laevis embryos are much more sensitive to a diverse set of chemical and molecular-biological perturbations when allowed to develop alone or in small groups, than in large groups. Keeping per-embryo exposure constant, we find that increasing the number of exposed embryos in a cohort increases the rate of survival while incidence of defects decreases. This inter-embryo assistance effect is mediated by short-range diffusible signals and involves the P2 ATP receptor. Our data and computational model emphasize that morphogenesis is a collective phenomenon not only at the level of cells, but also of whole bodies, and that cohort size is a crucial variable in studies of ecotoxicology, teratogenesis, and developmental plasticity.
Collapse
Affiliation(s)
- Angela Tung
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Megan M Sperry
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Wesley Clawson
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Ananya Pavuluri
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Sydney Bulatao
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Michelle Yue
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Ramses Martinez Flores
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Patrick McMillen
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Franz Kuchling
- Allen Discovery Center at Tufts University, Medford, MA, 02155, 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.
| |
Collapse
|
4
|
Gabriel GC, Lo CW. Molecular Pathways and Animal Models of Defects in Situs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1441:719-738. [PMID: 38884745 DOI: 10.1007/978-3-031-44087-8_43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Left-right patterning is among the least well understood of the three axes defining the body plan, and yet it is no less important, with left-right patterning defects causing structural birth defects with high morbidity and mortality, such as complex congenital heart disease, biliary atresia, or intestinal malrotation. The cell signaling pathways governing left-right asymmetry are highly conserved and involve multiple components of the TGF-β superfamily of cell signaling molecules. Central to left-right patterning is the differential activation of Nodal on the left, and BMP signaling on the right. In addition, a plethora of other cell signaling pathways including Shh, FGF, and Notch also contribute to the regulation of left-right patterning. In vertebrate embryos such as the mouse, frog, or zebrafish, the specification of left-right identity requires the left-right organizer (LRO) containing cells with motile and primary cilia that mediate the left-sided propagation of Nodal signaling, followed by left-sided activation of Lefty and then Pitx2, a transcription factor that specifies visceral organ asymmetry. While this overall scheme is well conserved, there are striking species differences, including the finding that motile cilia do not play a role in left-right patterning in some vertebrates. Surprisingly, the direction of heart looping, one of the first signs of organ left-right asymmetry, was recently shown to be specified by intrinsic cell chirality, not Nodal signaling, possibly a reflection of the early origin of Nodal signaling in radially symmetric organisms. How this intrinsic chirality interacts with downstream molecular pathways regulating visceral organ asymmetry will need to be further investigated to elucidate how disturbance in left-right patterning may contribute to complex CHD.
Collapse
Affiliation(s)
- George C Gabriel
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Cecilia W Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| |
Collapse
|
5
|
Manicka S, Pai VP, Levin M. Information integration during bioelectric regulation of morphogenesis of the embryonic frog brain. iScience 2023; 26:108398. [PMID: 38034358 PMCID: PMC10687303 DOI: 10.1016/j.isci.2023.108398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 07/18/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
Spatiotemporal patterns of cellular resting potential regulate several aspects of development. One key aspect of the bioelectric code is that transcriptional and morphogenetic states are determined not by local, single-cell, voltage levels but by specific distributions of voltage across cell sheets. We constructed and analyzed a minimal dynamical model of collective gene expression in cells based on inputs of multicellular voltage patterns. Causal integration analysis revealed a higher-order mechanism by which information about the voltage pattern was spatiotemporally integrated into gene activity, as well as a division of labor among and between the bioelectric and genetic components. We tested and confirmed predictions of this model in a system in which bioelectric control of morphogenesis regulates gene expression and organogenesis: the embryonic brain of the frog Xenopus laevis. This study demonstrates that machine learning and computational integration approaches can advance our understanding of the information-processing underlying morphogenetic decision-making, with a potential for other applications in developmental biology and regenerative medicine.
Collapse
Affiliation(s)
- Santosh Manicka
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Vaibhav P. Pai
- Allen Discovery Center at Tufts University, Medford, MA 02155, 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
| |
Collapse
|
6
|
Levin M. Bioelectric networks: the cognitive glue enabling evolutionary scaling from physiology to mind. Anim Cogn 2023; 26:1865-1891. [PMID: 37204591 PMCID: PMC10770221 DOI: 10.1007/s10071-023-01780-3] [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: 11/28/2022] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023]
Abstract
Each of us made the remarkable journey from mere matter to mind: starting life as a quiescent oocyte ("just chemistry and physics"), and slowly, gradually, becoming an adult human with complex metacognitive processes, hopes, and dreams. In addition, even though we feel ourselves to be a unified, single Self, distinct from the emergent dynamics of termite mounds and other swarms, the reality is that all intelligence is collective intelligence: each of us consists of a huge number of cells working together to generate a coherent cognitive being with goals, preferences, and memories that belong to the whole and not to its parts. Basal cognition is the quest to understand how Mind scales-how large numbers of competent subunits can work together to become intelligences that expand the scale of their possible goals. Crucially, the remarkable trick of turning homeostatic, cell-level physiological competencies into large-scale behavioral intelligences is not limited to the electrical dynamics of the brain. Evolution was using bioelectric signaling long before neurons and muscles appeared, to solve the problem of creating and repairing complex bodies. In this Perspective, I review the deep symmetry between the intelligence of developmental morphogenesis and that of classical behavior. I describe the highly conserved mechanisms that enable the collective intelligence of cells to implement regulative embryogenesis, regeneration, and cancer suppression. I sketch the story of an evolutionary pivot that repurposed the algorithms and cellular machinery that enable navigation of morphospace into the behavioral navigation of the 3D world which we so readily recognize as intelligence. Understanding the bioelectric dynamics that underlie construction of complex bodies and brains provides an essential path to understanding the natural evolution, and bioengineered design, of diverse intelligences within and beyond the phylogenetic history of Earth.
Collapse
Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, 200 Boston Ave., Suite 4600, Medford, MA, 02155, USA.
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, USA.
| |
Collapse
|
7
|
Evans JP, Sen CK. Electrochemical Devices in Cutaneous Wound Healing. Bioengineering (Basel) 2023; 10:711. [PMID: 37370642 PMCID: PMC10295280 DOI: 10.3390/bioengineering10060711] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
In healthy skin, vectorial ion transport gives rise to a transepithelial potential which directly impacts many physiological aspects of skin function. A wound is a physical defect that breaches the epithelial barrier and changes the electrochemical environment of skin. Electroceutical dressings are devices that manipulate the electrochemical environment, host as well as microbial, of a wound. In this review, electroceuticals are organized into three mechanistic classes: ionic, wireless, and battery powered. All three classes of electroceutical dressing show encouraging effects on infection management and wound healing with evidence of favorable impact on keratinocyte migration and disruption of wound biofilm infection. This foundation sets the stage for further mechanistic as well as interventional studies. Successful conduct of such studies will determine the best dosage, timing, and class of stimulus necessary to maximize therapeutic efficacy.
Collapse
Affiliation(s)
| | - Chandan K. Sen
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| |
Collapse
|
8
|
Forrest K, Barricella AC, Pohar SA, Hinman AM, Amack JD. Understanding laterality disorders and the left-right organizer: Insights from zebrafish. Front Cell Dev Biol 2022; 10:1035513. [PMID: 36619867 PMCID: PMC9816872 DOI: 10.3389/fcell.2022.1035513] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Vital internal organs display a left-right (LR) asymmetric arrangement that is established during embryonic development. Disruption of this LR asymmetry-or laterality-can result in congenital organ malformations. Situs inversus totalis (SIT) is a complete concordant reversal of internal organs that results in a low occurrence of clinical consequences. Situs ambiguous, which gives rise to Heterotaxy syndrome (HTX), is characterized by discordant development and arrangement of organs that is associated with a wide range of birth defects. The leading cause of health problems in HTX patients is a congenital heart malformation. Mutations identified in patients with laterality disorders implicate motile cilia in establishing LR asymmetry. However, the cellular and molecular mechanisms underlying SIT and HTX are not fully understood. In several vertebrates, including mouse, frog and zebrafish, motile cilia located in a "left-right organizer" (LRO) trigger conserved signaling pathways that guide asymmetric organ development. Perturbation of LRO formation and/or function in animal models recapitulates organ malformations observed in SIT and HTX patients. This provides an opportunity to use these models to investigate the embryological origins of laterality disorders. The zebrafish embryo has emerged as an important model for investigating the earliest steps of LRO development. Here, we discuss clinical characteristics of human laterality disorders, and highlight experimental results from zebrafish that provide insights into LRO biology and advance our understanding of human laterality disorders.
Collapse
Affiliation(s)
- Kadeen Forrest
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, United States
| | - Alexandria C. Barricella
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, United States
| | - Sonny A. Pohar
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, United States
| | - Anna Maria Hinman
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, United States
| | - Jeffrey D. Amack
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, United States
- BioInspired Syracuse: Institute for Material and Living Systems, Syracuse, NY, United States
| |
Collapse
|
9
|
Petri N, Nordbrink R, Tsikolia N, Kremnyov S. Abnormal left-right organizer and laterality defects in Xenopus embryos after formin inhibitor SMIFH2 treatment. PLoS One 2022; 17:e0275164. [PMCID: PMC9639825 DOI: 10.1371/journal.pone.0275164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 09/12/2022] [Indexed: 11/09/2022] Open
Abstract
Left-right symmetry breaking in most studied vertebrates makes use of so-called leftward flow, a mechanism which was studied in detail especially in mouse and Xenopus laevis embryos and is based on rotation of monocilia on specialized epithelial surface designated as left-right organizer or laterality coordinator. However, it has been argued that prior to emergence of leftward flow an additional mechanism operates during early cleavage stages in Xenopus embryo which is based on cytoskeletal processes. Evidence in favour of this early mechanism was supported by left-right abnormalities after chemical inhibition of cytoskeletal protein formin. Here we analyzed temporal dimension of this effect in detail and found that reported abnormalities arise only after treatment at gastrula-neurula stages, i.e. just prior to and during the operation of left-right organizer. Moreover, molecular and morphological analysis of the left-right organizer reveals its abnormal development. Our results strongly indicate that left-right abnormalities reported after formin inhibition cannot serve as support of models based on early symmetry breaking event in Xenopus embryo.
Collapse
Affiliation(s)
- Natalia Petri
- Department of Embryology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Rhea Nordbrink
- Anatomy and Embryology, University Medicine Göttingen, Göttingen, Germany
| | - Nikoloz Tsikolia
- Anatomy and Embryology, University Medicine Göttingen, Göttingen, Germany
- * E-mail: (NT); (SK)
| | - Stanislav Kremnyov
- Department of Embryology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
- Laboratory of Morphogenesis Evolution, Koltzov Institute of Developmental Biology RAS, Moscow, Russia
- * E-mail: (NT); (SK)
| |
Collapse
|
10
|
Sempou E, Kostiuk V, Zhu J, Cecilia Guerra M, Tyan L, Hwang W, Camacho-Aguilar E, Caplan MJ, Zenisek D, Warmflash A, Owens NDL, Khokha MK. Membrane potential drives the exit from pluripotency and cell fate commitment via calcium and mTOR. Nat Commun 2022; 13:6681. [PMID: 36335122 PMCID: PMC9637099 DOI: 10.1038/s41467-022-34363-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 10/24/2022] [Indexed: 11/08/2022] Open
Abstract
Transitioning from pluripotency to differentiated cell fates is fundamental to both embryonic development and adult tissue homeostasis. Improving our understanding of this transition would facilitate our ability to manipulate pluripotent cells into tissues for therapeutic use. Here, we show that membrane voltage (Vm) regulates the exit from pluripotency and the onset of germ layer differentiation in the embryo, a process that affects both gastrulation and left-right patterning. By examining candidate genes of congenital heart disease and heterotaxy, we identify KCNH6, a member of the ether-a-go-go class of potassium channels that hyperpolarizes the Vm and thus limits the activation of voltage gated calcium channels, lowering intracellular calcium. In pluripotent embryonic cells, depletion of kcnh6 leads to membrane depolarization, elevation of intracellular calcium levels, and the maintenance of a pluripotent state at the expense of differentiation into ectodermal and myogenic lineages. Using high-resolution temporal transcriptome analysis, we identify the gene regulatory networks downstream of membrane depolarization and calcium signaling and discover that inhibition of the mTOR pathway transitions the pluripotent cell to a differentiated fate. By manipulating Vm using a suite of tools, we establish a bioelectric pathway that regulates pluripotency in vertebrates, including human embryonic stem cells.
Collapse
Affiliation(s)
- Emily Sempou
- Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - Valentyna Kostiuk
- Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - Jie Zhu
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - M Cecilia Guerra
- Departments of Biosciences and Bioengineering Rice University, 345 Anderson Biological Labs, Houston, TX, 77005, USA
| | - Leonid Tyan
- Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - Woong Hwang
- Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - Elena Camacho-Aguilar
- Departments of Biosciences and Bioengineering Rice University, 345 Anderson Biological Labs, Houston, TX, 77005, USA
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - David Zenisek
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - Aryeh Warmflash
- Departments of Biosciences and Bioengineering Rice University, 345 Anderson Biological Labs, Houston, TX, 77005, USA
| | - Nick D L Owens
- Department of Clinical and Biomedical Sciences, University of Exeter, Barrack Road, Exeter, EX2 5DW, UK
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA.
| |
Collapse
|
11
|
Endosomal v-ATPase as a Sensor Determining Myocardial Substrate Preference. Metabolites 2022; 12:metabo12070579. [PMID: 35888703 PMCID: PMC9316095 DOI: 10.3390/metabo12070579] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 11/17/2022] Open
Abstract
The heart is a metabolically flexible omnivore that can utilize a variety of substrates for energy provision. To fulfill cardiac energy requirements, the healthy adult heart mainly uses long-chain fatty acids and glucose in a balanced manner, but when exposed to physiological or pathological stimuli, it can switch its substrate preference to alternative substrates such as amino acids (AAs) and ketone bodies. Using the failing heart as an example, upon stress, the fatty acid/glucose substrate balance is upset, resulting in an over-reliance on either fatty acids or glucose. A chronic fuel shift towards a single type of substrate is linked with cardiac dysfunction. Re-balancing myocardial substrate preference is suggested as an effective strategy to rescue the failing heart. In the last decade, we revealed that vacuolar-type H+-ATPase (v-ATPase) functions as a key regulator of myocardial substrate preference and, therefore, as a novel potential treatment approach for the failing heart. Fatty acids, glucose, and AAs selectively influence the assembly state of v-ATPase resulting in modulation of its proton-pumping activity. In this review, we summarize these novel insights on v-ATPase as an integrator of nutritional information. We also describe its exploitation as a therapeutic target with focus on supplementation of AA as a nutraceutical approach to fight lipid-induced insulin resistance and contractile dysfunction of the heart.
Collapse
|
12
|
Fields C, Levin M. Competency in Navigating Arbitrary Spaces as an Invariant for Analyzing Cognition in Diverse Embodiments. ENTROPY 2022; 24:e24060819. [PMID: 35741540 PMCID: PMC9222757 DOI: 10.3390/e24060819] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/26/2022] [Accepted: 06/08/2022] [Indexed: 12/20/2022]
Abstract
One of the most salient features of life is its capacity to handle novelty and namely to thrive and adapt to new circumstances and changes in both the environment and internal components. An understanding of this capacity is central to several fields: the evolution of form and function, the design of effective strategies for biomedicine, and the creation of novel life forms via chimeric and bioengineering technologies. Here, we review instructive examples of living organisms solving diverse problems and propose competent navigation in arbitrary spaces as an invariant for thinking about the scaling of cognition during evolution. We argue that our innate capacity to recognize agency and intelligence in unfamiliar guises lags far behind our ability to detect it in familiar behavioral contexts. The multi-scale competency of life is essential to adaptive function, potentiating evolution and providing strategies for top-down control (not micromanagement) to address complex disease and injury. We propose an observer-focused viewpoint that is agnostic about scale and implementation, illustrating how evolution pivoted similar strategies to explore and exploit metabolic, transcriptional, morphological, and finally 3D motion spaces. By generalizing the concept of behavior, we gain novel perspectives on evolution, strategies for system-level biomedical interventions, and the construction of bioengineered intelligences. This framework is a first step toward relating to intelligence in highly unfamiliar embodiments, which will be essential for progress in artificial intelligence and regenerative medicine and for thriving in a world increasingly populated by synthetic, bio-robotic, and hybrid beings.
Collapse
Affiliation(s)
- Chris Fields
- Allen Discovery Center at Tufts University, Science and Engineering Complex, 200 College Ave., Medford, MA 02155, USA;
| | - Michael Levin
- Allen Discovery Center at Tufts University, Science and Engineering Complex, 200 College Ave., Medford, MA 02155, USA;
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA 02115, USA
- Correspondence:
| |
Collapse
|
13
|
Abstract
Embryonic cells grow in environments that provide a plethora of physical cues, including mechanical forces that shape the development of the entire embryo. Despite their prevalence, the role of these forces in embryonic development and their integration with chemical signals have been mostly neglected, and scrutiny in modern molecular embryology tilted, instead, towards the dissection of molecular pathways involved in cell fate determination and patterning. It is now possible to investigate how mechanical signals induce downstream genetic regulatory networks to regulate key developmental processes in the embryo. Here, we review the insights into mechanical control of early vertebrate development, including the role of forces in tissue patterning and embryonic axis formation. We also highlight recent in vitro approaches using individual embryonic stem cells and self-organizing multicellular models of human embryos, which have been instrumental in expanding our understanding of how mechanics tune cell fate and cellular rearrangements during human embryonic development.
Collapse
|
14
|
Regulating Endogenous Neural Stem Cell Activation to Promote Spinal Cord Injury Repair. Cells 2022; 11:cells11050846. [PMID: 35269466 PMCID: PMC8909806 DOI: 10.3390/cells11050846] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) affects millions of individuals worldwide. Currently, there is no cure, and treatment options to promote neural recovery are limited. An innovative approach to improve outcomes following SCI involves the recruitment of endogenous populations of neural stem cells (NSCs). NSCs can be isolated from the neuroaxis of the central nervous system (CNS), with brain and spinal cord populations sharing common characteristics (as well as regionally distinct phenotypes). Within the spinal cord, a number of NSC sub-populations have been identified which display unique protein expression profiles and proliferation kinetics. Collectively, the potential for NSCs to impact regenerative medicine strategies hinges on their cardinal properties, including self-renewal and multipotency (the ability to generate de novo neurons, astrocytes, and oligodendrocytes). Accordingly, endogenous NSCs could be harnessed to replace lost cells and promote structural repair following SCI. While studies exploring the efficacy of this approach continue to suggest its potential, many questions remain including those related to heterogeneity within the NSC pool, the interaction of NSCs with their environment, and the identification of factors that can enhance their response. We discuss the current state of knowledge regarding populations of endogenous spinal cord NSCs, their niche, and the factors that regulate their behavior. In an attempt to move towards the goal of enhancing neural repair, we highlight approaches that promote NSC activation following injury including the modulation of the microenvironment and parenchymal cells, pharmaceuticals, and applied electrical stimulation.
Collapse
|
15
|
McMillen P, Oudin MJ, Levin M, Payne SL. Beyond Neurons: Long Distance Communication in Development and Cancer. Front Cell Dev Biol 2021; 9:739024. [PMID: 34621752 PMCID: PMC8491768 DOI: 10.3389/fcell.2021.739024] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/31/2021] [Indexed: 12/12/2022] Open
Abstract
Cellular communication is important in all aspects of tissue and organism functioning, from the level of single cells, two discreet populations, and distant tissues of the body. Long distance communication networks integrate individual cells into tissues to maintain a complex organism during development, but when communication between cells goes awry, disease states such as cancer emerge. Herein we discuss the growing body of evidence suggesting that communication methods known to be employed by neurons, also exist in other cell types. We identify three major areas of long-distance communication: bioelectric signaling, tunneling nanotubes (TNTs), and macrophage modulation of networks, and draw comparisons about how these systems operate in the context of development and cancer. Bioelectric signaling occurs between cells through exchange of ions and tissue-level electric fields, leading to changes in biochemical gradients and molecular signaling pathways to control normal development and tumor growth and invasion in cancer. TNTs transport key morphogens and other cargo long distances, mediating electrical coupling, tissue patterning, and malignancy of cancer cells. Lastly macrophages maintain long distance signaling networks through trafficking of vesicles during development, providing communication relays and priming favorable microenvironments for cancer metastasis. By drawing comparisons between non-neural long distance signaling in the context of development and cancer we aim to encourage crosstalk between the two fields to cultivate new hypotheses and potential therapeutic strategies.
Collapse
Affiliation(s)
- Patrick McMillen
- Department of Biology, Allen Discovery Center, Tufts University, Medford, MA, United States
| | - Madeleine J Oudin
- Department of Biomedical Engineering, Tufts University, Medford, MA, United States
| | - Michael Levin
- Department of Biology, Allen Discovery Center, Tufts University, Medford, MA, United States
| | - Samantha L Payne
- Department of Biomedical Engineering, Tufts University, Medford, MA, United States
| |
Collapse
|
16
|
Abstract
It has previously been reported that in ex vivo planar explants prepared from Xenopus laevis embryos, the intracellular pH (pHi) increases in cells of the dorsal ectoderm from stage 10.5 to 11.5 (i.e. 11-12.5 hpf). It was proposed that such increases (potentially due to H+ being extruded, sequestered, or buffered in some manner), play a role in regulating neural induction. Here, we used an extracellular ion-selective electrode to non-invasively measure H+ fluxes at eight locations around the equatorial circumference of intact X. laevis embryos between stages 9-12 (˜7-13.25 hpf). We showed that at stages 9-11, there was a small H+ efflux recorded from all the measuring positions. At stage 12 there was a small, but significant, increase in the efflux of H+ from most locations, but the efflux from the dorsal side of the embryo was significantly greater than from the other positions. Embryos were also treated from stages 9-12 with bafilomycin A1, to block the activity of the ATP-driven H+ pump. By stage 22 (24 hpf), these embryos displayed retarded development, arresting before the end of gastrulation and therefore did not display the usual anterior and neural structures, which were observed in the solvent-control embryos. In addition, expression of the early neural gene, Zic3, was absent in treated embryos compared with the solvent controls. Together, our new in vivo data corroborated and extended the earlier explant-derived report describing changes in pHi that were suggested to play a role during neural induction in X. laevis embryos.
Collapse
|
17
|
Grodstein J, Levin M. Stability and robustness properties of bioelectric networks: A computational approach. BIOPHYSICS REVIEWS 2021; 2:031305. [PMID: 38505634 PMCID: PMC10903393 DOI: 10.1063/5.0062442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/07/2021] [Indexed: 03/21/2024]
Abstract
Morphogenesis during development and regeneration requires cells to communicate and cooperate toward the construction of complex anatomical structures. One important set of mechanisms for coordinating growth and form occurs via developmental bioelectricity-the dynamics of cellular networks driving changes of resting membrane potential which interface with transcriptional and biomechanical downstream cascades. While many molecular details have been elucidated about the instructive processes mediated by ion channel-dependent signaling outside of the nervous system, future advances in regenerative medicine and bioengineering require the understanding of tissue, organ, or whole body-level properties. A key aspect of bioelectric networks is their robustness, which can drive correct, invariant patterning cues despite changing cell number and anatomical configuration of the underlying tissue network. Here, we computationally analyze the minimal models of bioelectric networks and use the example of the regenerating planarian flatworm, to reveal important system-level aspects of bioelectrically derived patterns. These analyses promote an understanding of the robustness of circuits controlling regeneration and suggest design properties that can be exploited for synthetic bioengineering.
Collapse
Affiliation(s)
- Joel Grodstein
- Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155, USA
| | | |
Collapse
|
18
|
Santra P, Amack JD. Loss of vacuolar-type H+-ATPase induces caspase-independent necrosis-like death of hair cells in zebrafish neuromasts. Dis Model Mech 2021; 14:dmm048997. [PMID: 34296747 PMCID: PMC8319552 DOI: 10.1242/dmm.048997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/15/2021] [Indexed: 01/24/2023] Open
Abstract
The vacuolar-type H+-ATPase (V-ATPase) is a multi-subunit proton pump that regulates cellular pH. V-ATPase activity modulates several cellular processes, but cell-type-specific functions remain poorly understood. Patients with mutations in specific V-ATPase subunits can develop sensorineural deafness, but the underlying mechanisms are unclear. Here, we show that V-ATPase mutations disrupt the formation of zebrafish neuromasts, which serve as a model to investigate hearing loss. V-ATPase mutant neuromasts are small and contain pyknotic nuclei that denote dying cells. Molecular markers and live imaging show that loss of V-ATPase induces mechanosensory hair cells in neuromasts, but not neighboring support cells, to undergo caspase-independent necrosis-like cell death. This is the first demonstration that loss of V-ATPase can lead to necrosis-like cell death in a specific cell type in vivo. Mechanistically, loss of V-ATPase reduces mitochondrial membrane potential in hair cells. Modulating the mitochondrial permeability transition pore, which regulates mitochondrial membrane potential, improves hair cell survival. These results have implications for understanding the causes of sensorineural deafness, and more broadly, reveal functions for V-ATPase in promoting survival of a specific cell type in vivo.
Collapse
Affiliation(s)
- Peu Santra
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Jeffrey D. Amack
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Syracuse: Institute for Material and Living Systems, Syracuse, NY 13244, USA
| |
Collapse
|
19
|
Novel vertebrate- and brain-specific driver of neuronal outgrowth. Prog Neurobiol 2021; 202:102069. [PMID: 33933532 DOI: 10.1016/j.pneurobio.2021.102069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 03/31/2021] [Accepted: 04/21/2021] [Indexed: 12/30/2022]
Abstract
During the process of neuronal outgrowth, developing neurons produce new projections, neurites, that are essential for brain wiring. Here, we discover a relatively late-evolved protein that we denote Ac45-related protein (Ac45RP) and that, surprisingly, drives neuronal outgrowth. Ac45RP is a paralog of the Ac45 protein that is a component of the vacuolar proton ATPase (V-ATPase), the main pH regulator in eukaryotic cells. Ac45RP mRNA expression is brain specific and coincides with the peak of neurogenesis and the onset of synaptogenesis. Furthermore, Ac45RP physically interacts with the V-ATPase V0-sector and colocalizes with V0 in unconventional, but not synaptic, secretory vesicles of extending neurites. Excess Ac45RP enhances the expression of V0-subunits, causes a more elaborate Golgi, and increases the number of cytoplasmic vesicular structures, plasma membrane formation and outgrowth of actin-containing neurites devoid of synaptic markers. CRISPR-cas9n-mediated Ac45RP knockdown reduces neurite outgrowth. We conclude that the novel vertebrate- and brain-specific Ac45RP is a V0-interacting constituent of unconventional vesicular structures that drives membrane expansion during neurite outgrowth and as such may furnish a tool for future neuroregenerative treatment strategies.
Collapse
|
20
|
Onjiko RM, Nemes P, Moody SA. Altering metabolite distribution at Xenopus cleavage stages affects left-right gene expression asymmetries. Genesis 2021; 59:e23418. [PMID: 33826226 DOI: 10.1002/dvg.23418] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/22/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023]
Abstract
The left-right (L-R) axis of most bilateral animals is established during gastrulation when a transient ciliated structure creates a directional flow of signaling molecules that establish asymmetric gene expression in the lateral plate mesoderm. However, in some animals, an earlier differential distribution of molecules and cell division patterns initiate or at least influence L-R patterning. Using single-cell high-resolution mass spectrometry, we previously reported a limited number of small molecule (metabolite) concentration differences between left and right dorsal-animal blastomeres of the eight-cell Xenopus embryo. Herein, we examined whether altering the distribution of some of these molecules influenced early events in L-R patterning. Using lineage tracing, we found that injecting right-enriched metabolites into the left cell caused its descendant cells to disperse in patterns that varied from those in control gastrulae; this did not occur when left-enriched metabolites were injected into the right cell. At later stages, injecting left-enriched metabolites into the right cell perturbed the expression of genes known to: (a) be required for the formation of the gastrocoel roof plate (foxj1); (b) lead to the asymmetric expression of Nodal (dand5/coco); or (c) result from asymmetrical nodal expression (pitx2). Despite these perturbations in gene expression, we did not observe heterotaxy in heart or gut looping at tadpole stages. These studies indicate that altering metabolite distribution at cleavage stages at the concentrations tested in this study impacts the earliest steps of L-R gene expression that then can be compensated for during organogenesis.
Collapse
Affiliation(s)
- Rosemary M Onjiko
- Department of Chemistry, The George Washington University, Washington, District of Columbia
| | - Peter Nemes
- Department of Chemistry, The George Washington University, Washington, District of Columbia.,Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia.,Department of Chemistry & Biochemistry, University of Maryland, College Park, Maryland
| | - Sally A Moody
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia
| |
Collapse
|
21
|
Bioelectric signaling: Reprogrammable circuits underlying embryogenesis, regeneration, and cancer. Cell 2021; 184:1971-1989. [PMID: 33826908 DOI: 10.1016/j.cell.2021.02.034] [Citation(s) in RCA: 117] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/08/2021] [Accepted: 02/16/2021] [Indexed: 12/16/2022]
Abstract
How are individual cell behaviors coordinated toward invariant large-scale anatomical outcomes in development and regeneration despite unpredictable perturbations? Endogenous distributions of membrane potentials, produced by ion channels and gap junctions, are present across all tissues. These bioelectrical networks process morphogenetic information that controls gene expression, enabling cell collectives to make decisions about large-scale growth and form. Recent progress in the analysis and computational modeling of developmental bioelectric circuits and channelopathies reveals how cellular collectives cooperate toward organ-level structural order. These advances suggest a roadmap for exploiting bioelectric signaling for interventions addressing developmental disorders, regenerative medicine, cancer reprogramming, and synthetic bioengineering.
Collapse
|
22
|
Srivastava P, Kane A, Harrison C, Levin M. A Meta-Analysis of Bioelectric Data in Cancer, Embryogenesis, and Regeneration. Bioelectricity 2021; 3:42-67. [PMID: 34476377 DOI: 10.1089/bioe.2019.0034] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Developmental bioelectricity is the study of the endogenous role of bioelectrical signaling in all cell types. Resting potentials and other aspects of ionic cell physiology are known to be important regulatory parameters in embryogenesis, regeneration, and cancer. However, relevant quantitative measurement and genetic phenotyping data are distributed throughout wide-ranging literature, hampering experimental design and hypothesis generation. Here, we analyze published studies on bioelectrics and transcriptomic and genomic/phenotypic databases to provide a novel synthesis of what is known in three important aspects of bioelectrics research. First, we provide a comprehensive list of channelopathies-ion channel and pump gene mutations-in a range of important model systems with developmental patterning phenotypes, illustrating the breadth of channel types, tissues, and phyla (including man) in which bioelectric signaling is a critical endogenous aspect of embryogenesis. Second, we perform a novel bioinformatic analysis of transcriptomic data during regeneration in diverse taxa that reveals an electrogenic protein to be the one common factor specifically expressed in regeneration blastemas across Kingdoms. Finally, we analyze data on distinct Vmem signatures in normal and cancer cells, revealing a specific bioelectrical signature corresponding to some types of malignancies. These analyses shed light on fundamental questions in developmental bioelectricity and suggest new avenues for research in this exciting field.
Collapse
Affiliation(s)
- Pranjal Srivastava
- Rye High School, Rye, New York, USA; Current Affiliation: College of Chemistry, University of California, Berkeley, Berkeley, California, USA
| | - Anna Kane
- Department of Biology, Allen Discovery Center, Tufts University, Medford, Massachusetts, USA
| | - Christina Harrison
- Department of Biology, Allen Discovery Center, Tufts University, Medford, Massachusetts, USA
| | - Michael Levin
- Department of Biology, Allen Discovery Center, Tufts University, Medford, Massachusetts, USA
| |
Collapse
|
23
|
Abstract
Embryogenesis, as well as regeneration, is increasingly recognized to be orchestrated by an interplay of transcriptional and bioelectric networks. Spatiotemporal patterns of resting potentials direct the size, shape, and locations of numerous organ primordia during patterning. These bioelectrical properties are established by the function of ion channels and pumps that set voltage potentials of individual cells, and gap junctions (electrical synapses) that enable physiological states to propagate across tissue networks. Functional experiments to probe the roles of bioelectrical states can be carried out by targeting endogenous ion channels during development. Here, we describe protocols, optimized for the highly tractable Xenopus laevis embryo, for molecular genetic targeting of ion channels and connexins based on CRISPR, and monitoring of resting potential states using voltage-sensing fluorescent dye. Similar strategies can be adapted to other model species.
Collapse
Affiliation(s)
- Vasilios Nanos
- Department of Biology, and Allen Discovery Center, Tufts University, Medford, MA, USA
| | - Michael Levin
- Department of Biology, and Allen Discovery Center, Tufts University, Medford, MA, USA.
| |
Collapse
|
24
|
Cervera J, Ramirez P, Levin M, Mafe S. Community effects allow bioelectrical reprogramming of cell membrane potentials in multicellular aggregates: Model simulations. Phys Rev E 2020; 102:052412. [PMID: 33327213 DOI: 10.1103/physreve.102.052412] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/04/2020] [Indexed: 12/11/2022]
Abstract
Bioelectrical patterns are established by spatiotemporal correlations of cell membrane potentials at the multicellular level, being crucial to development, regeneration, and tumorigenesis. We have conducted multicellular simulations on bioelectrical community effects and intercellular coupling in multicellular aggregates. The simulations aim at establishing under which conditions a local heterogeneity consisting of a small patch of cells can be stabilized against a large aggregate of surrounding identical cells which are in a different bioelectrical state. In this way, instructive bioelectrical information can be persistently encoded in spatiotemporal patterns of separated domains with different cell polarization states. The multicellular community effects obtained are regulated both at the single-cell and intercellular levels, and emerge from a delicate balance between the degrees of intercellular coupling in: (i) the small patch, (ii) the surrounding bulk, and (iii) the interface that separates these two regions. The model is experimentally motivated and consists of two generic voltage-gated ion channels that attempt to establish the depolarized and polarized cell states together with coupling conductances whose individual and intercellular different states permit a dynamic multicellular connectivity. The simulations suggest that community effects may allow the reprogramming of single-cell bioelectrical states, in agreement with recent experimental data. A better understanding of the resulting electrical regionalization can assist the electroceutical correction of abnormally depolarized regions initiated in the bulk of normal tissues as well as suggest new biophysical mechanisms for the establishment of target patterns in multicellular engineering.
Collapse
Affiliation(s)
- Javier Cervera
- Departamento Termodinàmica, Universitat de València, E-46100 Burjassot, Spain
| | - Patricio Ramirez
- Departamento Física Aplicada, Universidad Politécnica de Valencia, E-46022 Valencia, Spain
| | - Michael Levin
- Department of Biology and Allen Discovery Center at Tufts University, Medford, Massachusetts 02155-4243, USA
| | - Salvador Mafe
- Departamento Termodinàmica, Universitat de València, E-46100 Burjassot, Spain
| |
Collapse
|
25
|
24-Epibrassinolide protects against ethanol-induced behavioural teratogenesis in zebrafish embryo. Chem Biol Interact 2020; 328:109193. [PMID: 32668205 DOI: 10.1016/j.cbi.2020.109193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/18/2020] [Accepted: 07/09/2020] [Indexed: 12/14/2022]
Abstract
Embryonic studies have demonstrated the neurotoxic, teratogenic, and neurobehavioral toxicity of ethanol (EtOH). Although multiple mechanisms may contribute to these effects, oxidative stress has been described as the major damage pathway. In this regard, natural antioxidants have the potential to counteract oxidative stress-induced cellular damage. Therefore, the present study aimed to investigate the potential protective role of 24-epibrassinolide (24-EPI), a natural brassinosteroid with proved antioxidant properties, in EtOH-induced teratogenic effects during early zebrafish development. Embryos (~2 h post-fertilization - hpf) were exposed to 1 % EtOH, co-exposed to 24-EPI (0.01, 0.1 and 1 μM) and to 24-EPI alone (1 μM) for 24 h. Following exposure, biochemical evaluations were made at 26 hpf, developmental analysis was made throughout the embryo-larval period, and behavioural responses were evaluated at 120 hpf. Exposure to 1 % EtOH caused an increase in the number of malformations, which were diminished by 24-EPI. In addition, EtOH induced an accumulation of GSSG and consequent reduction of GSH:GSSG ratio, indicating the involvement of oxidative mechanisms in the EtOH-induced effects. These were reverted by 24-EPI as proved by the GSSG levels and GSH:GSSG ratio that returned to control values. Furthermore, exposure to EtOH resulted in behavioural deficits at 120 hpf as observed by the disrupted response to an aversive stimulus, suggesting the involvement of neurotoxic mechanisms. 24-EPI restored the behavioural deficits observed in a dose-dependent manner. The absence of effects in the embryos exposed solely to 24-EPI showed its safety during the exposure period. In conclusion, EtOH caused developmental teratogenicity and behavioural toxicity by inducing glutathione changes, which were prevented by 24-EPI.
Collapse
|
26
|
Silver BB, Wolf AE, Lee J, Pang MF, Nelson CM. Epithelial tissue geometry directs emergence of bioelectric field and pattern of proliferation. Mol Biol Cell 2020; 31:1691-1702. [PMID: 32520653 PMCID: PMC7521849 DOI: 10.1091/mbc.e19-12-0719] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Patterns of proliferation are templated by both gradients of mechanical stress as well as by gradients in membrane voltage (Vm), which is defined as the electric potential difference between the cytoplasm and the extracellular medium. Either gradient could regulate the emergence of the other, or they could arise independently and synergistically affect proliferation within a tissue. Here, we examined the relationship between endogenous patterns of mechanical stress and the generation of bioelectric gradients in mammary epithelial tissues. We observed that the mechanical stress gradients in the tissues presaged gradients in both proliferation and depolarization, consistent with previous reports correlating depolarization with proliferation. Furthermore, disrupting the Vm gradient blocked the emergence of patterned proliferation. We found that the bioelectric gradient formed downstream of mechanical stresses within the tissues and depended on connexin-43 (Cx43) hemichannels, which opened preferentially in cells located in regions of high mechanical stress. Activation of Cx43 hemichannels was necessary for nuclear localization of Yap/Taz and induction of proliferation. Together, these results suggest that mechanotransduction triggers the formation of bioelectric gradients across a tissue, which are further translated into transcriptional changes that template patterns of growth.
Collapse
Affiliation(s)
- Brian B Silver
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Abraham E Wolf
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544
| | - Junuk Lee
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544
| | - Mei-Fong Pang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Celeste M Nelson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544.,Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544
| |
Collapse
|
27
|
Wang W, Zheng X, Song H, Yang J, Liu X, Wang Y, Zhang M, Zhang Z. Spatial and temporal deletion reveals a latent effect of Megf8 on the left-right patterning and heart development. Differentiation 2020; 113:19-25. [PMID: 32203821 DOI: 10.1016/j.diff.2020.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/10/2020] [Accepted: 03/10/2020] [Indexed: 01/23/2023]
Abstract
Laterality disease is frequently associated with congenital heart disease (CHD). However, it is unclear what is behind this association, a pleiotropic effect of common genetic causes of laterality diseases or the impact of abnormal left-right patterning on the downstream cardiovascular development. MEGF8 is a disease gene of Carpenter syndrome characterized by defective lateralization and CHD. Here we performed spatial and temporal deletion to dissect the tissue and time requirements of Megf8 on cardiovascular development. None of conditional deletions in cardiomyocytes, endothelium/endocardium, epicardium, cardiac mesoderm or neural crest cells led to cardiovascular defects. More surprisingly, temporal deletion with a ubiquitous Cre driver at embryonic day 7.5 (E7.5), a time point before symmetry break and cardiogenesis, causes preaxial polydactyly (PPD) and exencephaly, but not laterality and cardiovascular defects. These data suggested that Megf8 was dispensable for cardiac organogenesis. Only with E6.5 deletion, we observed aortic arch artery defects including right aortic arch, an indicator of reversed left-right patterning. The concurrence of laterality and cardiovascular defects in pre-streak stage deletion rather than cardiac organogenesis stage deletion indicates that the laterality defect may directly impact heart development. Interestingly, the latent effect of Megf8 on the left-right patterning suggests that the regulation of laterality may be much earlier than we previously thought.
Collapse
Affiliation(s)
- Wenfeng Wang
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Xiaoling Zheng
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Hejie Song
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Junjie Yang
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Xiangyang Liu
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Ye Wang
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Min Zhang
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Zhen Zhang
- Shanghai Pediatric Congenital Heart Disease Institute and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
| |
Collapse
|
28
|
Zhang Z, Dubiak KM, Huber PW, Dovichi NJ. Miniaturized Filter-Aided Sample Preparation (MICRO-FASP) Method for High Throughput, Ultrasensitive Proteomics Sample Preparation Reveals Proteome Asymmetry in Xenopus laevis Embryos. Anal Chem 2020; 92:5554-5560. [PMID: 32125139 DOI: 10.1021/acs.analchem.0c00470] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We report a miniaturized filter aided sample preparation method (micro-FASP) for low-loss preparation of submicrogram proteomic samples. The method employs a filter with ∼0.1 mm2 surface area, reduces the total volume of reagents to <10 μL, and requires only two sample transfer steps. The method was used to generate 25 883 unique peptides and 3069 protein groups from 1000 MCF-7 cells (∼100 ng protein content), and 13 367 peptides and 1895 protein groups were identified from 100 MCF-7 cells (∼10 ng protein content). Single blastomeres from Xenopus laevis embryos at the 50-cell stage (∼200 ng yolk free protein/blastomere) generated 20 943 unique peptides and 2597 protein groups; the proteomic profile clearly differentiated left and right blastomeres and provides strong support for models in which this asymmetry is established early in the embryo. The parallel processing of 12 samples demonstrates reproducible label free quantitation of 1 μg protein homogenates.
Collapse
Affiliation(s)
- Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 United States
| | - Kyle M Dubiak
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 United States
| | - Paul W Huber
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 United States
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 United States
| |
Collapse
|
29
|
Abstract
Selective serotonin reuptake inhibitor (SSRI) drugs, targeting serotonin transport, are widely used. A puzzling and biomedically important phenomenon concerns the persistent sexual dysfunction following SSRI use seen in some patients. What could be the mechanism of a persistent physiological state brought on by a transient exposure to serotonin transport blockers? In this study, we briefly review the clinical facts concerning this side effect of serotonin reuptake inhibitors and suggest a possible mechanism. Bioelectric circuits (among neural or non-neural cells) could persistently maintain alterations of bioelectric cell properties (resting potential), resulting in long-term changes in electrophysiology and signaling. We present new data revealing this phenomenon in planarian flatworms, in which brief SSRI exposures induce long-lasting changes in resting potential profile. We also briefly review recent data linking neurotransmitter signaling to developmental bioelectrics. Further study of tissue bioelectric memory could enable the design of ionoceutical interventions to counteract side effects of SSRIs and similar drugs.
Collapse
Affiliation(s)
- David Healy
- Hergest Unit, Department of Psychiatry, Bangor University, Bangor, Wales
| | - Joshua LaPalme
- Allen Discovery Center, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, Massachusetts
| |
Collapse
|
30
|
Pai VP, Adams DS. Preventing Ethanol-Induced Brain and Eye Morphology Defects Using Optogenetics. Bioelectricity 2019; 1:260-272. [PMID: 32685918 DOI: 10.1089/bioe.2019.0008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Embryonic exposure to the teratogen ethanol leads to dysmorphias, including eye and brain morphology defects associated with fetal alcohol spectrum disorder (FASD). Exposure of Xenopus laevis embryos to ethanol leads to similar developmental defects, including brain and eye dysmorphism, confirming our work and the work of others showing Xenopus as a useful system for studies of the brain and eye birth defects associated with FASD. Several targets of ethanol action have been hypothesized, one being regulation of Kir2.1 potassium channel. Endogenous ion fluxes and membrane voltage variation (bioelectric signals) have been shown to be powerful regulators of embryonic cell behaviors that are required for correct brain and eye morphology. Disruptions to these voltage patterns lead to spatially correlated disruptions in gene expression patterns and corresponding morphology. Materials and Methods: Here, we use controlled membrane voltage modulation to determine when and where voltage modulation is sufficient to rescue ethanol-induced brain and eye defects in Xenopus embryos. Results: We found (1) that modulating membrane voltage using light activation of the channelrhodopsin-2 variant D156A rescues ethanol exposed embryos, resulting in normal brain and eye morphologies; (2) hyperpolarization is required for the full duration of ethanol exposure; (3) hyperpolarization of only superficial ectoderm is sufficient for this effect; and(4) the rescue effect acts at a distance. Conclusions: These results, particularly the last, raise the exciting possibility of using bioelectric modulation to treat ethanol-induced brain and eye birth defects, possibly with extant ion channel drugs already prescribed to pregnant women. This may prove to be a simple and cost-effective strategy for reducing the impact of FASD.
Collapse
Affiliation(s)
- Vaibhav P Pai
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
| | - Dany Spencer Adams
- Department of Biology, Tufts University, Medford, Massachusetts.,Ion Diagnostics LLC, Watertown, Massachusetts
| |
Collapse
|
31
|
Toward Decoding Bioelectric Events in Xenopus Embryogenesis: New Methodology for Tracking Interplay Between Calcium and Resting Potentials In Vivo. J Mol Biol 2019; 432:605-620. [PMID: 31711960 DOI: 10.1016/j.jmb.2019.10.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 10/07/2019] [Accepted: 10/15/2019] [Indexed: 12/16/2022]
Abstract
Although chemical signaling during embryogenesis is readily addressed by a plethora of available techniques, the developmental functions of ionic signaling are still poorly understood. It is increasingly realized that bioelectric events in nonneural cells are critical for pattern regulation, but their study has been hampered by difficulties in monitoring and manipulating them in vivo. Recent developments in visualizing electrical signaling dynamics in the field of neuroscience have facilitated functional experiments that reveal instructive developmental bioelectric signals. However, there is a pressing need for additional tools to explore time-dependent ionic signaling to understand complex endogenous dynamics. Here, we present methodological advances, including 4D imaging and data analysis, for improved tracking of calcium flux in the Xenopus laevis embryo, lowering the barrier for in vivo physiology work in this important model system. Using these techniques, we investigated the relationship between bioelectric ion channel activity and calcium, finding that cell hyperpolarization and depolarization both induce persistent static elevation of cytoplasmic calcium levels that fade over developmental time. These calcium changes correlate with increased cell mobility in early embryos and abnormal craniofacial morphology in later embryos. We thus highlight membrane potential modulation as a tractable tool for modulation of signaling cascades that rely on calcium as a transduction mechanism. The methods we describe facilitate the study of important novel aspects of developmental physiology, are extendable to numerous classes of existing and forthcoming fluorescent physiological reporters, and establish highly accessible, inexpensive protocols for their investigation.
Collapse
|
32
|
Bioelectrical controls of morphogenesis: from ancient mechanisms of cell coordination to biomedical opportunities. Curr Opin Genet Dev 2019; 57:61-69. [PMID: 31442749 DOI: 10.1016/j.gde.2019.06.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/06/2019] [Accepted: 06/18/2019] [Indexed: 11/21/2022]
Abstract
Cell-to-cell communication is a cornerstone of multicellular existence. The ancient mechanism of sharing information between cells using the conductance of ions across cell membranes and the propagation of electrical signals through tissue space is a powerful means of efficiently controlling cell decisions and behaviors. Our understanding of how cells use changes in 'bioelectrical' signals to elicit systems-level responses has dramatically improved in recent years. We are now in a position to not just describe these changes, but to also predictively alter them to learn more about their importance for developmental biology and regenerative medicine. Recent work is helping researchers construct a more integrative view of how these simple controls can orchestrate downstream changes in protein signaling pathways and gene regulatory networks. In this review, we highlight experiments and analyses that have led to new insights in bioelectrical controls, specifically as key modulators of complex pattern formation and tissue regeneration. We also discuss opportunities for the development of new therapeutic approaches in regenerative medicine applications by exploiting this fundamental biological phenomenon.
Collapse
|
33
|
Abstract
Consistent asymmetries between the left and right sides of animal bodies are common. For example, the internal organs of vertebrates are left-right (L-R) asymmetric in a stereotyped fashion. Other structures, such as the skeleton and muscles, are largely symmetric. This Review considers how symmetries and asymmetries form alongside each other within the embryo, and how they are then maintained during growth. I describe how asymmetric signals are generated in the embryo. Using the limbs and somites as major examples, I then address mechanisms for protecting symmetrically forming tissues from asymmetrically acting signals. These examples reveal that symmetry should not be considered as an inherent background state, but instead must be actively maintained throughout multiple phases of embryonic patterning and organismal growth.
Collapse
Affiliation(s)
- Daniel T Grimes
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, OR 97403, USA
| |
Collapse
|
34
|
Levin M, Pietak AM, Bischof J. Planarian regeneration as a model of anatomical homeostasis: Recent progress in biophysical and computational approaches. Semin Cell Dev Biol 2019; 87:125-144. [PMID: 29635019 PMCID: PMC6234102 DOI: 10.1016/j.semcdb.2018.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 12/22/2022]
Abstract
Planarian behavior, physiology, and pattern control offer profound lessons for regenerative medicine, evolutionary biology, morphogenetic engineering, robotics, and unconventional computation. Despite recent advances in the molecular genetics of stem cell differentiation, this model organism's remarkable anatomical homeostasis provokes us with truly fundamental puzzles about the origin of large-scale shape and its relationship to the genome. In this review article, we first highlight several deep mysteries about planarian regeneration in the context of the current paradigm in this field. We then review recent progress in understanding of the physiological control of an endogenous, bioelectric pattern memory that guides regeneration, and how modulating this memory can permanently alter the flatworm's target morphology. Finally, we focus on computational approaches that complement reductive pathway analysis with synthetic, systems-level understanding of morphological decision-making. We analyze existing models of planarian pattern control and highlight recent successes and remaining knowledge gaps in this interdisciplinary frontier field.
Collapse
Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States; Biology Department, Tufts University, Medford, MA 02155, United States.
| | - Alexis M Pietak
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States; Biology Department, Tufts University, Medford, MA 02155, United States
| |
Collapse
|
35
|
Bérard A, Levin M, Sadler T, Healy D. Selective Serotonin Reuptake Inhibitor Use During Pregnancy and Major Malformations: The Importance of Serotonin for Embryonic Development and the Effect of Serotonin Inhibition on the Occurrence of Malformations. Bioelectricity 2019; 1:18-29. [PMID: 34471805 DOI: 10.1089/bioe.2018.0003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Bioelectric signaling is transduced by neurotransmitter pathways in many cell types. One of the key mediators of bioelectric control mechanisms is serotonin, and its transporter SERT, which is targeted by a broad class of blocker drugs (selective serotonin reuptake inhibitors [SSRIs]). Studies showing an increased risk of multiple malformations associated with gestational use of SSRI have been accumulating but debate remains on whether SSRI as a class has the potential to generate these malformations. This review highlights the importance of serotonin for embryonic development; the effect of serotonin inhibition during early pregnancy on the occurrence of multiple diverse malformations that have been shown to occur in human pregnancies; that the risks outweigh the benefits of SSRI use during gestation in populations of mild to moderately depressed pregnant women, which encompass the majority of pregnant depressed women; and that the malformations seen in human pregnancies constitute a pattern of malformations consistent with the known mechanisms of action of SSRIs. We present at least three mechanisms by which SSRI can affect development. These studies highlight the relevance of basic bioelectric and neurotransmitter mechanism for biomedicine.
Collapse
Affiliation(s)
- Anick Bérard
- Faculty of Pharmacy, University of Montreal; Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Michael Levin
- Allen Discovery Center at Tufts University, Department of Biology, Medford, Massachusetts
| | - Thomas Sadler
- Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, Utah
| | - David Healy
- Department of Psychiatry, Hergest Unit, Bangor, United Kingdom
| |
Collapse
|
36
|
|
37
|
Durant F, Bischof J, Fields C, Morokuma J, LaPalme J, Hoi A, Levin M. The Role of Early Bioelectric Signals in the Regeneration of Planarian Anterior/Posterior Polarity. Biophys J 2019; 116:948-961. [PMID: 30799071 DOI: 10.1016/j.bpj.2019.01.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 01/14/2023] Open
Abstract
Axial patterning during planarian regeneration relies on a transcriptional circuit that confers distinct positional information on the two ends of an amputated fragment. The earliest known elements of this system begin demarcating differences between anterior and posterior wounds by 6 h postamputation. However, it is still unknown what upstream events break the axial symmetry, allowing a mutual repressor system to establish invariant, distinct biochemical states at the anterior and posterior ends. Here, we show that bioelectric signaling at 3 h is crucial for the formation of proper anterior-posterior polarity in planaria. Briefly manipulating the endogenous bioelectric state by depolarizing the injured tissue during the first 3 h of regeneration alters gene expression by 6 h postamputation and leads to a double-headed phenotype upon regeneration despite confirmed washout of ionophores from tissue. These data reveal a primary functional role for resting membrane potential taking place within the first 3 h after injury and kick-starting the downstream pattern of events that elaborate anatomy over the following 10 days. We propose a simple model of molecular-genetic mechanisms to explain how physiological events taking place immediately after injury regulate the spatial distribution of downstream gene expression and anatomy of regenerating planaria.
Collapse
Affiliation(s)
- Fallon Durant
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Chris Fields
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Junji Morokuma
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Joshua LaPalme
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Alison Hoi
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts.
| |
Collapse
|
38
|
Bioelectrical coupling in multicellular domains regulated by gap junctions: A conceptual approach. Bioelectrochemistry 2018; 123:45-61. [DOI: 10.1016/j.bioelechem.2018.04.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 12/16/2022]
|
39
|
Birkholz TR, Van Huizen AV, Beane WS. Staying in shape: Planarians as a model for understanding regenerative morphology. Semin Cell Dev Biol 2018; 87:105-115. [PMID: 29738883 DOI: 10.1016/j.semcdb.2018.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/23/2018] [Accepted: 04/30/2018] [Indexed: 01/18/2023]
Abstract
A key requirement of tissue/organ regeneration is the ability to induce appropriate shape in situ. Regenerated structures need to be integrated with pre-existing ones, through the combined regulation of new tissue growth and the scaling of surrounding tissues. This requires a tightly coordinated control of individual cell functions such as proliferation and stem cell differentiation. While great strides have been made in elucidating cell growth and differentiation mechanisms, how overall shape is generated during regeneration remains unknown. This is because a significant gap remains in our understanding of how cell behaviors are coordinated at the level of tissues and organs. The highly regenerative planarian flatworm has emerged as an important model for defining and understanding regenerative shape mechanisms. This review provides an overview of the main processes known to regulate tissue and animal shape during planarian regeneration: adult stem cell regulation, the reestablishment of body axes, tissue remodeling in pre-existing structures, organ scaling and the maintenance of body proportion, and the bioelectrical regulation of animal morphology. In order for the field to move forward, it will be necessary to identify shape mutants as a means to uncover the molecular mechanisms that synchronize all these separate processes to produce the worm's final regenerative shape. This knowledge will also aid efforts to define the mechanisms that control the termination of regenerative processes.
Collapse
Affiliation(s)
- Taylor R Birkholz
- Department of Biological Sciences, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI, 49008, USA
| | - Alanna V Van Huizen
- Department of Biological Sciences, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI, 49008, USA
| | - Wendy S Beane
- Department of Biological Sciences, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI, 49008, USA.
| |
Collapse
|
40
|
Siregar P, Julen N, Hufnagl P, Mutter G. A general framework dedicated to computational morphogenesis Part I - Constitutive equations. Biosystems 2018; 173:298-313. [PMID: 30005999 DOI: 10.1016/j.biosystems.2018.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/30/2018] [Accepted: 07/05/2018] [Indexed: 01/14/2023]
Abstract
In order to understand living organisms, considerable experimental efforts and resources have been devoted to correlate genes and their expressions with cell, tissue, organ and whole organisms' phenotypes. This data driven approach to knowledge discovery has led to many breakthrough in our understanding of healthy and diseased states, and is paving the way to improve the diagnosis and treatment of diseases. Complementary to this data-driven approach, computational models of biological systems based on first principles have been developed in order to deepen our understanding of the multi-scale dynamics that drives normal and pathological biological functions. In this paper we describe the biological, physical and mathematical concepts that led to the design of a Computational Morphogenesis (CM) platform baptized Generic Modeling and Simulating Platform (GMSP). Its role is to generate realistic 3D multi-scale biological tissues from virtual stem cells and the intended target applications include in virtuo studies of normal and abnormal tissue (re)generation as well as the development of complex diseases such as carcinogenesis. At all space-scales of interest, biological agents interact with each other via biochemical, bioelectrical, and mechanical fields that operate in concert during embryogenesis, growth and adult life. The spatio-temporal dependencies of these fields can be modeled by physics-based constitutive equations that we propose to examine in relation to the landmark biological events that occur during embryogenesis.
Collapse
Affiliation(s)
| | | | - Peter Hufnagl
- Department of Digital Pathology and IT, Institute of Pathology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - George Mutter
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| |
Collapse
|
41
|
Abstract
TGF-β family ligands function in inducing and patterning many tissues of the early vertebrate embryonic body plan. Nodal signaling is essential for the specification of mesendodermal tissues and the concurrent cellular movements of gastrulation. Bone morphogenetic protein (BMP) signaling patterns tissues along the dorsal-ventral axis and simultaneously directs the cell movements of convergence and extension. After gastrulation, a second wave of Nodal signaling breaks the symmetry between the left and right sides of the embryo. During these processes, elaborate regulatory feedback between TGF-β ligands and their antagonists direct the proper specification and patterning of embryonic tissues. In this review, we summarize the current knowledge of the function and regulation of TGF-β family signaling in these processes. Although we cover principles that are involved in the development of all vertebrate embryos, we focus specifically on three popular model organisms: the mouse Mus musculus, the African clawed frog of the genus Xenopus, and the zebrafish Danio rerio, highlighting the similarities and differences between these species.
Collapse
Affiliation(s)
- Joseph Zinski
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6058
| | - Benjamin Tajer
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6058
| | - Mary C Mullins
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6058
| |
Collapse
|
42
|
Silver BB, Nelson CM. The Bioelectric Code: Reprogramming Cancer and Aging From the Interface of Mechanical and Chemical Microenvironments. Front Cell Dev Biol 2018; 6:21. [PMID: 29560350 PMCID: PMC5845671 DOI: 10.3389/fcell.2018.00021] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/15/2018] [Indexed: 12/12/2022] Open
Abstract
Cancer is a complex, heterogeneous group of diseases that can develop through many routes. Broad treatments such as chemotherapy destroy healthy cells in addition to cancerous ones, but more refined strategies that target specific pathways are usually only effective for a limited number of cancer types. This is largely due to the multitude of physiological variables that differ between cells and their surroundings. It is therefore important to understand how nature coordinates these variables into concerted regulation of growth at the tissue scale. The cellular microenvironment might then be manipulated to drive cells toward a desired outcome at the tissue level. One unexpected parameter, cellular membrane voltage (Vm), has been documented to exert control over cellular behavior both in culture and in vivo. Manipulating this fundamental cellular property influences a remarkable array of organism-wide patterning events, producing striking outcomes in both tumorigenesis as well as regeneration. These studies suggest that Vm is not only a key intrinsic cellular property, but also an integral part of the microenvironment that acts in both space and time to guide cellular behavior. As a result, there is considerable interest in manipulating Vm both to treat cancer as well as to regenerate organs damaged or deteriorated during aging. However, such manipulations have produced conflicting outcomes experimentally, which poses a substantial barrier to understanding the fundamentals of bioelectrical reprogramming. Here, we summarize these inconsistencies and discuss how the mechanical microenvironment may impact bioelectric regulation.
Collapse
Affiliation(s)
- Brian B Silver
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Celeste M Nelson
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
| |
Collapse
|
43
|
Sullivan KG, Levin M. Inverse Drug Screening of Bioelectric Signaling and Neurotransmitter Roles: Illustrated Using a Xenopus Tail Regeneration Assay. Cold Spring Harb Protoc 2018; 2018:pdb.prot099937. [PMID: 29437995 DOI: 10.1101/pdb.prot099937] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Xenopus embryos and larvae are an ideal model system in which to study the interplay between genetics, physiology, and anatomy in the control of structure and function. An important emerging field is the study of bioelectric signaling, the exchange of ion- and neurotransmitter-mediated messages among all types of cells (not just nerve and muscle cells), in the regulation of growth and form during embryogenesis, regeneration, and cancer. To facilitate the mechanistic investigation of bioelectric events in vivo, it is necessary to identify the endogenous signaling machinery involved in any patterning process of interest. This protocol uses the tail regeneration assay in Xenopus to perform an inverse drug screen; tiers of known compounds are used to probe the involvement of increasingly specific classes of bioelectric and neurotransmitter machinery. By using a hierarchical approach, large classes of targets are ruled out in early rounds, focusing attention on progressively narrower sets of proteins. Such a screen avoids many of the limitations of a molecular-genetic targeting approach and provides a rapid and efficient way to focus on specific targets. Usually, <10 experiments are needed to determine whether bioelectrics and/or neurotransmitter signaling are involved in the process of interest. This protocol describes the strategy in the context of a semiquantitative analysis of tail regeneration but can be applied to any assay in Xenopus or other small aquatic model system (e.g., zebrafish). Given the ever-increasing toolkit of chemical genetics, such screens represent a powerful and versatile methodology for probing the physiological circuits underlying pattern regulation.
Collapse
Affiliation(s)
- Kelly G Sullivan
- Biology Department, and Allen Discovery Center at Tufts University, Medford, Massachusetts 02155
| | - Michael Levin
- Biology Department, and Allen Discovery Center at Tufts University, Medford, Massachusetts 02155
| |
Collapse
|
44
|
Levin M, Martyniuk CJ. The bioelectric code: An ancient computational medium for dynamic control of growth and form. Biosystems 2018; 164:76-93. [PMID: 28855098 PMCID: PMC10464596 DOI: 10.1016/j.biosystems.2017.08.009] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/20/2017] [Accepted: 08/22/2017] [Indexed: 12/19/2022]
Abstract
What determines large-scale anatomy? DNA does not directly specify geometrical arrangements of tissues and organs, and a process of encoding and decoding for morphogenesis is required. Moreover, many species can regenerate and remodel their structure despite drastic injury. The ability to obtain the correct target morphology from a diversity of initial conditions reveals that the morphogenetic code implements a rich system of pattern-homeostatic processes. Here, we describe an important mechanism by which cellular networks implement pattern regulation and plasticity: bioelectricity. All cells, not only nerves and muscles, produce and sense electrical signals; in vivo, these processes form bioelectric circuits that harness individual cell behaviors toward specific anatomical endpoints. We review emerging progress in reading and re-writing anatomical information encoded in bioelectrical states, and discuss the approaches to this problem from the perspectives of information theory, dynamical systems, and computational neuroscience. Cracking the bioelectric code will enable much-improved control over biological patterning, advancing basic evolutionary developmental biology as well as enabling numerous applications in regenerative medicine and synthetic bioengineering.
Collapse
Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Biology Department, Tufts University, 200 Boston Avenue, Suite 4600 Medford, MA 02155, USA.
| | - Christopher J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| |
Collapse
|
45
|
McLaughlin KA, Levin M. Bioelectric signaling in regeneration: Mechanisms of ionic controls of growth and form. Dev Biol 2018; 433:177-189. [PMID: 29291972 PMCID: PMC5753428 DOI: 10.1016/j.ydbio.2017.08.032] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/23/2017] [Accepted: 08/28/2017] [Indexed: 12/11/2022]
Abstract
The ability to control pattern formation is critical for the both the embryonic development of complex structures as well as for the regeneration/repair of damaged or missing tissues and organs. In addition to chemical gradients and gene regulatory networks, endogenous ion flows are key regulators of cell behavior. Not only do bioelectric cues provide information needed for the initial development of structures, they also enable the robust restoration of normal pattern after injury. In order to expand our basic understanding of morphogenetic processes responsible for the repair of complex anatomy, we need to identify the roles of endogenous voltage gradients, ion flows, and electric fields. In complement to the current focus on molecular genetics, decoding the information transduced by bioelectric cues enhances our knowledge of the dynamic control of growth and pattern formation. Recent advances in science and technology place us in an exciting time to elucidate the interplay between molecular-genetic inputs and important biophysical cues that direct the creation of tissues and organs. Moving forward, these new insights enable additional approaches to direct cell behavior and may result in profound advances in augmentation of regenerative capacity.
Collapse
Affiliation(s)
- Kelly A McLaughlin
- Allen Discovery Center, Department of Biology, Tufts University, 200 Boston Ave., Suite 4700, Medford, MA 02155, United States.
| | - Michael Levin
- Allen Discovery Center, Department of Biology, Tufts University, 200 Boston Ave., Suite 4700, Medford, MA 02155, United States
| |
Collapse
|
46
|
Cowan JR, Tariq M, Shaw C, Rao M, Belmont JW, Lalani SR, Smolarek TA, Ware SM. Copy number variation as a genetic basis for heterotaxy and heterotaxy-spectrum congenital heart defects. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0406. [PMID: 27821535 DOI: 10.1098/rstb.2015.0406] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2016] [Indexed: 12/22/2022] Open
Abstract
Genomic disorders and rare copy number abnormalities are identified in 15-25% of patients with syndromic conditions, but their prevalence in individuals with isolated birth defects is less clear. A spectrum of congenital heart defects (CHDs) is seen in heterotaxy, a highly heritable and genetically heterogeneous multiple congenital anomaly syndrome resulting from failure to properly establish left-right (L-R) organ asymmetry during early embryonic development. To identify novel genetic causes of heterotaxy, we analysed copy number variants (CNVs) in 225 patients with heterotaxy and heterotaxy-spectrum CHDs using array-based genotyping methods. Clinically relevant CNVs were identified in approximately 20% of patients and encompassed both known and putative heterotaxy genes. Patients were carefully phenotyped, revealing a significant association of abdominal situs inversus with pathogenic or likely pathogenic CNVs, while d-transposition of the great arteries was more frequently associated with common CNVs. Identified cytogenetic abnormalities ranged from large unbalanced translocations to smaller, kilobase-scale CNVs, including a rare, single exon deletion in ZIC3, a gene known to cause X-linked heterotaxy. Morpholino loss-of-function experiments in Xenopus support a role for one of these novel candidates, the platelet isoform of phosphofructokinase-1 (PFKP) in heterotaxy. Collectively, our results confirm a high CNV yield for array-based testing in patients with heterotaxy, and support use of CNV analysis for identification of novel biological processes relevant to human laterality.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
Collapse
Affiliation(s)
- Jason R Cowan
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.,Department of Pediatrics and Medical and Molecular Genetics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Muhammad Tariq
- Department of Pediatrics and Medical and Molecular Genetics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Department of Clinical Biochemistry, University of Tabuk, Tabuk 71491, Kingdom of Saudi Arabia
| | - Chad Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mitchell Rao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - John W Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Teresa A Smolarek
- Cincinnati Children's Hospital Medical Center, Division of Human Genetics, Cincinnati, OH 45229, USA
| | - Stephanie M Ware
- Department of Pediatrics and Medical and Molecular Genetics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| |
Collapse
|
47
|
McDowell G, Rajadurai S, Levin M. From cytoskeletal dynamics to organ asymmetry: a nonlinear, regulative pathway underlies left-right patterning. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0409. [PMID: 27821521 DOI: 10.1098/rstb.2015.0409] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2016] [Indexed: 12/25/2022] Open
Abstract
Consistent left-right (LR) asymmetry is a fundamental aspect of the bodyplan across phyla, and errors of laterality form an important class of human birth defects. Its molecular underpinning was first discovered as a sequential pathway of left- and right-sided gene expression that controlled positioning of the heart and visceral organs. Recent data have revised this picture in two important ways. First, the physical origin of chirality has been identified; cytoskeletal dynamics underlie the asymmetry of single-cell behaviour and patterning of the LR axis. Second, the pathway is not linear: early disruptions that alter the normal sidedness of upstream asymmetric genes do not necessarily induce defects in the laterality of the downstream genes or in organ situs Thus, the LR pathway is a unique example of two fascinating aspects of biology: the interplay of physics and genetics in establishing large-scale anatomy, and regulative (shape-homeostatic) pathways that correct molecular and anatomical errors over time. Here, we review aspects of asymmetry from its intracellular, cytoplasmic origins to the recently uncovered ability of the LR control circuitry to achieve correct gene expression and morphology despite reversals of key 'determinant' genes. We provide novel functional data, in Xenopus laevis, on conserved elements of the cytoskeleton that drive asymmetry, and comparatively analyse it together with previously published results in the field. Our new observations and meta-analysis demonstrate that despite aberrant expression of upstream regulatory genes, embryos can progressively normalize transcriptional cascades and anatomical outcomes. LR patterning can thus serve as a paradigm of how subcellular physics and gene expression cooperate to achieve developmental robustness of a body axis.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
Collapse
Affiliation(s)
- Gary McDowell
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA.,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| | - Suvithan Rajadurai
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA.,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| | - Michael Levin
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA .,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| |
Collapse
|
48
|
Wan LQ, Chin AS, Worley KE, Ray P. Cell chirality: emergence of asymmetry from cell culture. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0413. [PMID: 27821525 DOI: 10.1098/rstb.2015.0413] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2016] [Indexed: 11/12/2022] Open
Abstract
Increasing evidence suggests that intrinsic cell chirality significantly contributes to the left-right (LR) asymmetry in embryonic development, which is a well-conserved characteristic of living organisms. With animal embryos, several theories have been established, but there are still controversies regarding mechanisms associated with embryonic LR symmetry breaking and the formation of asymmetric internal organs. Recently, in vitro systems have been developed to determine cell chirality and to recapitulate multicellular chiral morphogenesis on a chip. These studies demonstrate that chirality is indeed a universal property of the cell that can be observed with well-controlled experiments such as micropatterning. In this paper, we discuss the possible benefits of these in vitro systems to research in LR asymmetry, categorize available platforms for single-cell chirality and multicellular chiral morphogenesis, and review mathematical models used for in vitro cell chirality and its applications in in vivo embryonic development. These recent developments enable the interrogation of the intracellular machinery in LR axis establishment and accelerate research in birth defects in laterality.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
Collapse
Affiliation(s)
- Leo Q Wan
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA .,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA.,Center for Modeling, Simulation and Imaging in Medicine, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Amanda S Chin
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Kathryn E Worley
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Poulomi Ray
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| |
Collapse
|
49
|
Fields C, Levin M. Multiscale memory and bioelectric error correction in the cytoplasm-cytoskeleton-membrane system. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 10. [DOI: 10.1002/wsbm.1410] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/19/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Chris Fields
- 21 Rue des Lavandiéres, 11160 Caunes Minervois; France
| | - Michael Levin
- Allen Discovery Center at Tufts University; Medford MA USA
| |
Collapse
|
50
|
Pai VP, Willocq V, Pitcairn EJ, Lemire JM, Paré JF, Shi NQ, McLaughlin KA, Levin M. HCN4 ion channel function is required for early events that regulate anatomical left-right patterning in a nodal and lefty asymmetric gene expression-independent manner. Biol Open 2017; 6:1445-1457. [PMID: 28818840 PMCID: PMC5665463 DOI: 10.1242/bio.025957] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/12/2017] [Indexed: 12/13/2022] Open
Abstract
Laterality is a basic characteristic of all life forms, from single cell organisms to complex plants and animals. For many metazoans, consistent left-right asymmetric patterning is essential for the correct anatomy of internal organs, such as the heart, gut, and brain; disruption of left-right asymmetry patterning leads to an important class of birth defects in human patients. Laterality functions across multiple scales, where early embryonic, subcellular and chiral cytoskeletal events are coupled with asymmetric amplification mechanisms and gene regulatory networks leading to asymmetric physical forces that ultimately result in distinct left and right anatomical organ patterning. Recent studies have suggested the existence of multiple parallel pathways regulating organ asymmetry. Here, we show that an isoform of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of ion channels (hyperpolarization-activated cyclic nucleotide-gated channel 4, HCN4) is important for correct left-right patterning. HCN4 channels are present very early in Xenopus embryos. Blocking HCN channels (Ih currents) with pharmacological inhibitors leads to errors in organ situs. This effect is only seen when HCN4 channels are blocked early (pre-stage 10) and not by a later block (post-stage 10). Injections of HCN4-DN (dominant-negative) mRNA induce left-right defects only when injected in both blastomeres no later than the 2-cell stage. Analysis of key asymmetric genes' expression showed that the sidedness of Nodal, Lefty, and Pitx2 expression is largely unchanged by HCN4 blockade, despite the randomization of subsequent organ situs, although the area of Pitx2 expression was significantly reduced. Together these data identify a novel, developmental role for HCN4 channels and reveal a new Nodal-Lefty-Pitx2 asymmetric gene expression-independent mechanism upstream of organ positioning during embryonic left-right patterning.
Collapse
Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Emily J Pitcairn
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Joan M Lemire
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Jean-François Paré
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Nian-Qing Shi
- Department of Medicine at University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Kelly A McLaughlin
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| |
Collapse
|