1
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Lee HC, Oliveira NMM, Hastings C, Baillie-Benson P, Moverley AA, Lu HC, Zheng Y, Wilby EL, Weil TT, Page KM, Fu J, Moris N, Stern CD. Regulation of long-range BMP gradients and embryonic polarity by propagation of local calcium-firing activity. Nat Commun 2024; 15:1463. [PMID: 38368410 PMCID: PMC10874436 DOI: 10.1038/s41467-024-45772-4] [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: 06/01/2023] [Accepted: 02/02/2024] [Indexed: 02/19/2024] Open
Abstract
Many amniote vertebrate species including humans can form identical twins from a single embryo, but this only occurs rarely. It has been suggested that the primitive-streak-forming embryonic region emits signals that inhibit streak formation elsewhere but the signals involved, how they are transmitted and how they act has not been elucidated. Here we show that short tracks of calcium firing activity propagate through extraembryonic tissue via gap junctions and prevent ectopic primitive streak formation in chick embryos. Cross-regulation of calcium activity and an inhibitor of primitive streak formation (Bone Morphogenetic Protein, BMP) via NF-κB and NFAT establishes a long-range BMP gradient spanning the embryo. This mechanism explains how embryos of widely different sizes can maintain positional information that determines embryo polarity. We provide evidence for similar mechanisms in two different human embryo models and in Drosophila, suggesting an ancient evolutionary origin.
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Affiliation(s)
- Hyung Chul Lee
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
- School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, 77 Yongbong-ro, Gwangju, 61186, Korea.
| | - Nidia M M Oliveira
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- College of Professional Services, Murdoch University, 90 South St, Murdoch, WA, 6150, Australia
| | - Cato Hastings
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | | | - Adam A Moverley
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Cell and Developmental Biology, Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hui-Chun Lu
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Centre for Craniofacial & Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, Guy's Tower, London, SE1 9RT, UK
| | - Yi Zheng
- Departments of Mechanical Engineering, Biomedical Engineering, and Cell & Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
- BioInspired Syracuse Institute for Materials and Living Systems, Syracuse University, Syracuse, NY, USA
| | - Elise L Wilby
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Timothy T Weil
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Karen M Page
- Department of Mathematics, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jianping Fu
- Departments of Mechanical Engineering, Biomedical Engineering, and Cell & Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Naomi Moris
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
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2
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Paudel S, Yue M, Nalamalapu R, Saha MS. Deciphering the Calcium Code: A Review of Calcium Activity Analysis Methods Employed to Identify Meaningful Activity in Early Neural Development. Biomolecules 2024; 14:138. [PMID: 38275767 PMCID: PMC10813340 DOI: 10.3390/biom14010138] [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: 12/14/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
The intracellular and intercellular flux of calcium ions represents an ancient and universal mode of signaling that regulates an extensive array of cellular processes. Evidence for the central role of calcium signaling includes various techniques that allow the visualization of calcium activity in living cells. While extensively investigated in mature cells, calcium activity is equally important in developing cells, particularly the embryonic nervous system where it has been implicated in a wide variety array of determinative events. However, unlike in mature cells, where the calcium dynamics display regular, predictable patterns, calcium activity in developing systems is far more sporadic, irregular, and diverse. This renders the ability to assess calcium activity in a consistent manner extremely challenging, challenges reflected in the diversity of methods employed to analyze calcium activity in neural development. Here we review the wide array of calcium detection and analysis methods used across studies, limiting the extent to which they can be comparatively analyzed. The goal is to provide investigators not only with an overview of calcium activity analysis techniques currently available, but also to offer suggestions for future work and standardization to enable informative comparative evaluations of this fundamental and important process in neural development.
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Affiliation(s)
- Sudip Paudel
- Wyss Institute, Harvard University, Boston, MA 02215, USA; (S.P.); (M.Y.)
| | - Michelle Yue
- Wyss Institute, Harvard University, Boston, MA 02215, USA; (S.P.); (M.Y.)
| | - Rithvik Nalamalapu
- School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA;
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3
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Calcium sparks enhance the tissue fluidity within epithelial layers and promote apical extrusion of transformed cells. Cell Rep 2022; 40:111078. [PMID: 35830802 DOI: 10.1016/j.celrep.2022.111078] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/13/2022] [Accepted: 06/20/2022] [Indexed: 11/22/2022] Open
Abstract
In vertebrates, newly emerging transformed cells are often apically extruded from epithelial layers through cell competition with surrounding normal epithelial cells. However, the underlying molecular mechanism remains elusive. Here, using phospho-SILAC screening, we show that phosphorylation of AHNAK2 is elevated in normal cells neighboring RasV12 cells soon after the induction of RasV12 expression, which is mediated by calcium-dependent protein kinase C. In addition, transient upsurges of intracellular calcium, which we call calcium sparks, frequently occur in normal cells neighboring RasV12 cells, which are mediated by mechanosensitive calcium channel TRPC1 upon membrane stretching. Calcium sparks then enhance cell movements of both normal and RasV12 cells through phosphorylation of AHNAK2 and promote apical extrusion. Moreover, comparable calcium sparks positively regulate apical extrusion of RasV12-transformed cells in zebrafish larvae as well. Hence, calcium sparks play a crucial role in the elimination of transformed cells at the early phase of cell competition.
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4
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Baumgartner ME, Mastrogiannopoulos A, Kucinski I, Langton PF, Piddini E. The Gr64 cluster of gustatory receptors promotes survival and proteostasis of epithelial cells in Drosophila. PLoS Biol 2022; 20:e3001710. [PMID: 35862315 PMCID: PMC9302837 DOI: 10.1371/journal.pbio.3001710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 06/14/2022] [Indexed: 12/26/2022] Open
Abstract
Gustatory Receptor 64 (Gr64) genes are a cluster of 6 neuronally expressed receptors involved in sweet taste sensation in Drosophila melanogaster. Gr64s modulate calcium signalling and excitatory responses to several different sugars. Here, we discover an unexpected nonneuronal function of Gr64 receptors and show that they promote proteostasis in epithelial cells affected by proteotoxic stress. Using heterozygous mutations in ribosome proteins (Rp), which have recently been shown to induce proteotoxic stress and protein aggregates in cells, we show that Rp/+ cells in Drosophila imaginal discs up-regulate expression of the entire Gr64 cluster and depend on these receptors for survival. We further show that loss of Gr64 in Rp/+ cells exacerbates stress pathway activation and proteotoxic stress by negatively affecting autophagy and proteasome function. This work identifies a noncanonical role in proteostasis maintenance for a family of gustatory receptors known for their function in neuronal sensation.
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Affiliation(s)
- Michael E. Baumgartner
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | | | - Iwo Kucinski
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Zoology Department, University of Cambridge, Cambridge, United Kingdom
| | - Paul F. Langton
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Eugenia Piddini
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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5
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Redolfi N, García-Casas P, Fornetto C, Sonda S, Pizzo P, Pendin D. Lighting Up Ca 2+ Dynamics in Animal Models. Cells 2021; 10:2133. [PMID: 34440902 PMCID: PMC8392631 DOI: 10.3390/cells10082133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/08/2021] [Accepted: 08/16/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium (Ca2+) signaling coordinates are crucial processes in brain physiology. Particularly, fundamental aspects of neuronal function such as synaptic transmission and neuronal plasticity are regulated by Ca2+, and neuronal survival itself relies on Ca2+-dependent cascades. Indeed, impaired Ca2+ homeostasis has been reported in aging as well as in the onset and progression of neurodegeneration. Understanding the physiology of brain function and the key processes leading to its derangement is a core challenge for neuroscience. In this context, Ca2+ imaging represents a powerful tool, effectively fostered by the continuous amelioration of Ca2+ sensors in parallel with the improvement of imaging instrumentation. In this review, we explore the potentiality of the most used animal models employed for Ca2+ imaging, highlighting their application in brain research to explore the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paloma García-Casas
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Chiara Fornetto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Sonia Sonda
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
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6
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Calcium Activity Dynamics Correlate with Neuronal Phenotype at a Single Cell Level and in a Threshold-Dependent Manner. Int J Mol Sci 2019; 20:ijms20081880. [PMID: 30995769 PMCID: PMC6515432 DOI: 10.3390/ijms20081880] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/23/2022] Open
Abstract
Calcium is a ubiquitous signaling molecule that plays a vital role in many physiological processes. Recent work has shown that calcium activity is especially critical in vertebrate neural development. Here, we investigated if calcium activity and neuronal phenotype are correlated only on a population level or on the level of single cells. Using Xenopus primary cell culture in which individual cells can be unambiguously identified and associated with a molecular phenotype, we correlated calcium activity with neuronal phenotype on the single-cell level. This analysis revealed that, at the neural plate stage, a high frequency of low-amplitude spiking activity correlates with an excitatory, glutamatergic phenotype, while high-amplitude spiking activity correlates with an inhibitory, GABAergic phenotype. Surprisingly, we also found that high-frequency, low-amplitude spiking activity correlates with neural progenitor cells and that differentiating cells exhibit higher spike amplitude. Additional methods of analysis suggested that differentiating marker tubb2b-expressing cells exhibit relatively persistent and predictable calcium activity compared to the irregular activity of neural progenitor cells. Our study highlights the value of using a range of thresholds for analyzing calcium activity data and underscores the importance of employing multiple methods to characterize the often irregular, complex patterns of calcium activity during early neural development.
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7
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Brodskiy PA, Wu Q, Soundarrajan DK, Huizar FJ, Chen J, Liang P, Narciso C, Levis MK, Arredondo-Walsh N, Chen DZ, Zartman JJ. Decoding Calcium Signaling Dynamics during Drosophila Wing Disc Development. Biophys J 2019; 116:725-740. [PMID: 30704858 PMCID: PMC6382932 DOI: 10.1016/j.bpj.2019.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/04/2018] [Accepted: 01/04/2019] [Indexed: 01/07/2023] Open
Abstract
The robust specification of organ development depends on coordinated cell-cell communication. This process requires signal integration among multiple pathways, relying on second messengers such as calcium ions. Calcium signaling encodes a significant portion of the cellular state by regulating transcription factors, enzymes, and cytoskeletal proteins. However, the relationships between the inputs specifying cell and organ development, calcium signaling dynamics, and final organ morphology are poorly understood. Here, we have designed a quantitative image-analysis pipeline for decoding organ-level calcium signaling. With this pipeline, we extracted spatiotemporal features of calcium signaling dynamics during the development of the Drosophila larval wing disc, a genetic model for organogenesis. We identified specific classes of wing phenotypes that resulted from calcium signaling pathway perturbations, including defects in gross morphology, vein differentiation, and overall size. We found four qualitative classes of calcium signaling activity. These classes can be ordered based on agonist stimulation strength Gαq-mediated signaling. In vivo calcium signaling dynamics depend on both receptor tyrosine kinase/phospholipase C γ and G protein-coupled receptor/phospholipase C β activities. We found that spatially patterned calcium dynamics correlate with known differential growth rates between anterior and posterior compartments. Integrated calcium signaling activity decreases with increasing tissue size, and it responds to morphogenetic perturbations that impact organ growth. Together, these findings define how calcium signaling dynamics integrate upstream inputs to mediate multiple response outputs in developing epithelial organs.
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Affiliation(s)
- Pavel A Brodskiy
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Qinfeng Wu
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Dharsan K Soundarrajan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Francisco J Huizar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Jianxu Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Peixian Liang
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Cody Narciso
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Megan K Levis
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | | | - Danny Z Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Jeremiah J Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana.
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8
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Paudel S, Sindelar R, Saha M. Calcium Signaling in Vertebrate Development and Its Role in Disease. Int J Mol Sci 2018; 19:E3390. [PMID: 30380695 PMCID: PMC6274931 DOI: 10.3390/ijms19113390] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/18/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
Accumulating evidence over the past three decades suggests that altered calcium signaling during development may be a major driving force for adult pathophysiological events. Well over a hundred human genes encode proteins that are specifically dedicated to calcium homeostasis and calcium signaling, and the majority of these are expressed during embryonic development. Recent advances in molecular techniques have identified impaired calcium signaling during development due to either mutations or dysregulation of these proteins. This impaired signaling has been implicated in various human diseases ranging from cardiac malformations to epilepsy. Although the molecular basis of these and other diseases have been well studied in adult systems, the potential developmental origins of such diseases are less well characterized. In this review, we will discuss the recent evidence that examines different patterns of calcium activity during early development, as well as potential medical conditions associated with its dysregulation. Studies performed using various model organisms, including zebrafish, Xenopus, and mouse, have underscored the critical role of calcium activity in infertility, abortive pregnancy, developmental defects, and a range of diseases which manifest later in life. Understanding the underlying mechanisms by which calcium regulates these diverse developmental processes remains a challenge; however, this knowledge will potentially enable calcium signaling to be used as a therapeutic target in regenerative and personalized medicine.
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Affiliation(s)
- Sudip Paudel
- College of William and Mary, Williamsburg, VA 23187, USA.
| | - Regan Sindelar
- College of William and Mary, Williamsburg, VA 23187, USA.
| | - Margaret Saha
- College of William and Mary, Williamsburg, VA 23187, USA.
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9
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Markwardt ML, Snell NE, Guo M, Wu Y, Christensen R, Liu H, Shroff H, Rizzo MA. A Genetically Encoded Biosensor Strategy for Quantifying Non-muscle Myosin II Phosphorylation Dynamics in Living Cells and Organisms. Cell Rep 2018; 24:1060-1070.e4. [PMID: 30044973 PMCID: PMC6117825 DOI: 10.1016/j.celrep.2018.06.088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 05/25/2018] [Accepted: 06/20/2018] [Indexed: 02/06/2023] Open
Abstract
Complex cell behaviors require dynamic control over non-muscle myosin II (NMMII) regulatory light chain (RLC) phosphorylation. Here, we report that RLC phosphorylation can be tracked in living cells and organisms using a homotransfer fluorescence resonance energy transfer (FRET) approach. Fluorescent protein-tagged RLCs exhibit FRET in the dephosphorylated conformation, permitting identification and quantification of RLC phosphorylation in living cells. This approach is versatile and can accommodate several different fluorescent protein colors, thus enabling multiplexed imaging with complementary biosensors. In fibroblasts, dynamic myosin phosphorylation was observed at the leading edge of migrating cells and retracting structures where it persistently colocalized with activated myosin light chain kinase. Changes in myosin phosphorylation during C. elegans embryonic development were tracked using polarization inverted selective-plane illumination microscopy (piSPIM), revealing a shift in phosphorylated myosin localization to a longitudinal orientation following the onset of twitching. Quantitative analyses further suggested that RLC phosphorylation dynamics occur independently from changes in protein expression.
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Affiliation(s)
- Michele L Markwardt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nicole E Snell
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Min Guo
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, US NIH, Bethesda, MD 20814, USA
| | - Yicong Wu
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, US NIH, Bethesda, MD 20814, USA
| | - Ryan Christensen
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, US NIH, Bethesda, MD 20814, USA
| | - Huafeng Liu
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hari Shroff
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, US NIH, Bethesda, MD 20814, USA
| | - M A Rizzo
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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10
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Abstract
Decoding how tissue properties emerge across multiple spatial and temporal scales from the integration of local signals is a grand challenge in quantitative biology. For example, the collective behavior of epithelial cells is critical for shaping developing embryos. Understanding how epithelial cells interpret a diverse range of local signals to coordinate tissue-level processes requires a systems-level understanding of development. Integration of multiple signaling pathways that specify cell signaling information requires second messengers such as calcium ions. Increasingly, specific roles have been uncovered for calcium signaling throughout development. Calcium signaling regulates many processes including division, migration, death, and differentiation. However, the pleiotropic and ubiquitous nature of calcium signaling implies that many additional functions remain to be discovered. Here we review a selection of recent studies to highlight important insights into how multiple signals are transduced by calcium transients in developing epithelial tissues. Quantitative imaging and computational modeling have provided important insights into how calcium signaling integration occurs. Reverse-engineering the conserved features of signal integration mediated by calcium signaling will enable novel approaches in regenerative medicine and synthetic control of morphogenesis.
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Affiliation(s)
- Pavel A. Brodskiy
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 205 McCourtney Hall, Notre Dame, IN 46556, USA
| | - Jeremiah J. Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, 205 McCourtney Hall, Notre Dame, IN 46556, USA
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11
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Hayashi K, Yamamoto TS, Ueno N. Intracellular calcium signal at the leading edge regulates mesodermal sheet migration during Xenopus gastrulation. Sci Rep 2018; 8:2433. [PMID: 29402947 PMCID: PMC5799360 DOI: 10.1038/s41598-018-20747-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/23/2018] [Indexed: 12/15/2022] Open
Abstract
During the gastrulation stage in animal embryogenesis, the cells leading the axial mesoderm migrate toward the anterior side of the embryo, vigorously extending cell protrusions such as lamellipodia. It is thought that the leading cells sense gradients of chemoattractants emanating from the ectodermal cells and translate them to initiate and maintain the cell movements necessary for gastrulation. However, it is unclear how the extracellular information is converted to the intracellular chemical reactions that lead to motion. Here we demonstrated that intracellular Ca2+ levels in the protrusion-forming leading cells are markedly higher than those of the following cells and the axial mesoderm cells. We also showed that inhibiting the intracellular Ca2+ significantly retarded the gastrulation cell movements, while increasing the intracellular Ca2+ with an ionophore enhanced the migration. We further found that the ionophore treatment increased the active form of the small GTPase Rac1 in these cells. Our results suggest that transient intracellular Ca2+ signals play an essential role in the active cell migration during gastrulation.
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Affiliation(s)
- Kentaro Hayashi
- Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
- Department of Basic Biology, School of Life Science, The Graduate University of Advanced Studies (SOKENDAI), 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Takamasa S Yamamoto
- Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Naoto Ueno
- Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan.
- Department of Basic Biology, School of Life Science, The Graduate University of Advanced Studies (SOKENDAI), 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan.
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12
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Calcium spikes, waves and oscillations in a large, patterned epithelial tissue. Sci Rep 2017; 7:42786. [PMID: 28218282 PMCID: PMC5317010 DOI: 10.1038/srep42786] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 01/17/2017] [Indexed: 12/31/2022] Open
Abstract
While calcium signaling in excitable cells, such as muscle or neurons, is extensively characterized, calcium signaling in epithelial tissues is little understood. Specifically, the range of intercellular calcium signaling patterns elicited by tightly coupled epithelial cells and their function in the regulation of epithelial characteristics are little explored. We found that in Drosophila imaginal discs, a widely studied epithelial model organ, complex spatiotemporal calcium dynamics occur. We describe patterns that include intercellular waves traversing large tissue domains in striking oscillatory patterns as well as spikes confined to local domains of neighboring cells. The spatiotemporal characteristics of intercellular waves and oscillations arise as emergent properties of calcium mobilization within a sheet of gap-junction coupled cells and are influenced by cell size and environmental history. While the in vivo function of spikes, waves and oscillations requires further characterization, our genetic experiments suggest that core calcium signaling components guide actomyosin organization. Our study thus suggests a possible role for calcium signaling in epithelia but importantly, introduces a model epithelium enabling the dissection of cellular mechanisms supporting the initiation, transmission and regeneration of long-range intercellular calcium waves and the emergence of oscillations in a highly coupled multicellular sheet.
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13
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Kong D, Wolf F, Großhans J. Forces directing germ-band extension in Drosophila embryos. Mech Dev 2016; 144:11-22. [PMID: 28013027 DOI: 10.1016/j.mod.2016.12.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 01/06/2023]
Abstract
Body axis elongation by convergent extension is a conserved developmental process found in all metazoans. Drosophila embryonic germ-band extension is an important morphogenetic process during embryogenesis, by which the length of the germ-band is more than doubled along the anterior-posterior axis. This lengthening is achieved by typical convergent extension, i.e. narrowing the lateral epidermis along the dorsal-ventral axis and simultaneous extension along the anterior-posterior axis. Germ-band extension is largely driven by cell intercalation, whose directionality is determined by the planar polarity of the tissue and ultimately by the anterior-posterior patterning system. In addition, extrinsic tensile forces originating from the invaginating endoderm induce cell shape changes, which transiently contribute to germ-band extension. Here, we review recent progress in understanding of the role of mechanical forces in germ-band extension.
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Affiliation(s)
- Deqing Kong
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Fred Wolf
- Department of Nonlinear Dynamics, Max Planck Institute for Dynamics and Self-Organisation, Faculty of Physics, Bernstein Center for Computational Neuroscience, University of Göttingen, Am Faßberg 17, 37077 Göttingen, Germany
| | - Jörg Großhans
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany.
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