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Brown RI, Barber HM, Kucenas S. Satellite glial cell manipulation prior to axotomy enhances developing dorsal root ganglion central branch regrowth into the spinal cord. Glia 2024; 72:1766-1784. [PMID: 39141572 PMCID: PMC11325082 DOI: 10.1002/glia.24581] [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: 12/05/2023] [Revised: 05/30/2024] [Accepted: 06/02/2024] [Indexed: 08/16/2024]
Abstract
The central and peripheral nervous systems (CNS and PNS, respectively) exhibit remarkable diversity in the capacity to regenerate following neuronal injury with PNS injuries being much more likely to regenerate than those that occur in the CNS. Glial responses to damage greatly influence the likelihood of regeneration by either promoting or inhibiting axonal regrowth over time. However, despite our understanding of how some glial lineages participate in nerve degeneration and regeneration, less is known about the contributions of peripheral satellite glial cells (SGC) to regeneration failure following central axon branch injury of dorsal root ganglia (DRG) sensory neurons. Here, using in vivo, time-lapse imaging in larval zebrafish coupled with laser axotomy, we investigate the role of SGCs in axonal regeneration. In our studies we show that SGCs respond to injury by relocating their nuclei to the injury site during the same period that DRG neurons produce new central branch neurites. Laser ablation of SGCs prior to axon injury results in more neurite growth attempts and ultimately a higher rate of successful central axon regrowth, implicating SGCs as inhibitors of regeneration. We also demonstrate that this SGC response is mediated in part by ErbB signaling, as chemical inhibition of this receptor results in reduced SGC motility and enhanced central axon regrowth. These findings provide new insights into SGC-neuron interactions under injury conditions and how these interactions influence nervous system repair.
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Affiliation(s)
- Robin I Brown
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA
| | - Heather M Barber
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA
- Cell & Developmental Biology Graduate Program, University of Virginia, Charlottesville, Virginia, USA
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA
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2
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Curran BM, Nickerson KR, Yung AR, Goodrich LV, Jaworski A, Tessier-Lavigne M, Ma L. Multiple guidance mechanisms control axon growth to generate precise T-shaped bifurcation during dorsal funiculus development in the spinal cord. eLife 2024; 13:RP94109. [PMID: 39159057 PMCID: PMC11333043 DOI: 10.7554/elife.94109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2024] Open
Abstract
The dorsal funiculus in the spinal cord relays somatosensory information to the brain. It is made of T-shaped bifurcation of dorsal root ganglion (DRG) sensory axons. Our previous study has shown that Slit signaling is required for proper guidance during bifurcation, but loss of Slit does not affect all DRG axons. Here, we examined the role of the extracellular molecule Netrin-1 (Ntn1). Using wholemount staining with tissue clearing, we showed that mice lacking Ntn1 had axons escaping from the dorsal funiculus at the time of bifurcation. Genetic labeling confirmed that these misprojecting axons come from DRG neurons. Single axon analysis showed that loss of Ntn1 did not affect bifurcation but rather altered turning angles. To distinguish their guidance functions, we examined mice with triple deletion of Ntn1, Slit1, and Slit2 and found a completely disorganized dorsal funiculus. Comparing mice with different genotypes using immunolabeling and single axon tracing revealed additive guidance errors, demonstrating the independent roles of Ntn1 and Slit. Moreover, the same defects were observed in embryos lacking their cognate receptors. These in vivo studies thus demonstrate the presence of multi-factorial guidance mechanisms that ensure proper formation of a common branched axonal structure during spinal cord development.
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Affiliation(s)
- Bridget M Curran
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber, Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Kelsey R Nickerson
- Department of Neuroscience, Brown UniversityProvidenceUnited States
- Robert J. and Nancy D. Carney Institute for Brain ScienceProvidenceUnited States
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Alexander Jaworski
- Department of Neuroscience, Brown UniversityProvidenceUnited States
- Robert J. and Nancy D. Carney Institute for Brain ScienceProvidenceUnited States
| | | | - Le Ma
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber, Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson UniversityPhiladelphiaUnited States
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3
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Curran BM, Nickerson KR, Yung AR, Goodrich LV, Jaworski A, Tessier-Lavigne M, Ma L. Multiple Guidance Mechanisms Control Axon Growth to Generate Precise T-shaped Bifurcation during Dorsal Funiculus Development in the Spinal Cord. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.17.567638. [PMID: 38014092 PMCID: PMC10680847 DOI: 10.1101/2023.11.17.567638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The dorsal funiculus in the spinal cord relays somatosensory information to the brain. It is made of T-shaped bifurcation of dorsal root ganglion (DRG) sensory axons. Our previous study has shown that Slit signaling is required for proper guidance during bifurcation, but loss of Slit does not affect all DRG axons. Here, we examined the role of the extracellular molecule Netrin-1 (Ntn1). Using wholemount staining with tissue clearing, we showed that mice lacking Ntn1 have axons escaping from the dorsal funiculus at the time of bifurcation. Genetic labeling confirmed that these misprojecting axons come from DRG neurons. Single axon analysis showed that loss of Ntn1 does not affect bifurcation but rather alters turning angles. To distinguish their guidance functions, we examined mice with triple deletion of Ntn1, Slit1, and Slit2 and found a completely disorganized dorsal funiculus. Comparing mice with different genotypes using immunolabeling and single axon tracing revealed additive guidance errors, demonstrating the independent roles of Ntn1 and Slit. Moreover, the same defects were observed in embryos lacking their cognate receptors. These in vivo studies thus demonstrate the presence of multi-factorial guidance mechanisms that ensure proper formation of a common branched axonal structure during spinal cord development.
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Affiliation(s)
- Bridget M Curran
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
| | - Kelsey R Nickerson
- Department of Neuroscience, Brown University, Providence, RI 02912
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, RI 02912
- Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912
| | | | - Le Ma
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107
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4
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Kenny-Ganzert IW, Sherwood DR. The C. elegans anchor cell: A model to elucidate mechanisms underlying invasion through basement membrane. Semin Cell Dev Biol 2024; 154:23-34. [PMID: 37422376 PMCID: PMC10592375 DOI: 10.1016/j.semcdb.2023.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 07/10/2023]
Abstract
Cell invasion through basement membrane barriers is crucial during many developmental processes and in immune surveillance. Dysregulation of invasion also drives the pathology of numerous human diseases, such as metastasis and inflammatory disorders. Cell invasion involves dynamic interactions between the invading cell, basement membrane, and neighboring tissues. Owing to this complexity, cell invasion is challenging to study in vivo, which has hampered the understanding of mechanisms controlling invasion. Caenorhabditis elegans anchor cell invasion is a powerful in vivo model where subcellular imaging of cell-basement membrane interactions can be combined with genetic, genomic, and single-cell molecular perturbation studies. In this review, we outline insights gained by studying anchor cell invasion, which span transcriptional networks, translational regulation, secretory apparatus expansion, dynamic and adaptable protrusions that breach and clear basement membrane, and a complex, localized metabolic network that fuels invasion. Together, investigation of anchor cell invasion is building a comprehensive understanding of the mechanisms that underlie invasion, which we expect will ultimately facilitate better therapeutic strategies to control cell invasive activity in human disease.
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Affiliation(s)
| | - David R Sherwood
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA.
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5
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Rapti G. Regulation of axon pathfinding by astroglia across genetic model organisms. Front Cell Neurosci 2023; 17:1241957. [PMID: 37941606 PMCID: PMC10628440 DOI: 10.3389/fncel.2023.1241957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 09/07/2023] [Indexed: 11/10/2023] Open
Abstract
Glia and neurons are intimately associated throughout bilaterian nervous systems, and were early proposed to interact for patterning circuit assembly. The investigations of circuit formation progressed from early hypotheses of intermediate guideposts and a "glia blueprint", to recent genetic and cell manipulations, and visualizations in vivo. An array of molecular factors are implicated in axon pathfinding but their number appears small relatively to circuit complexity. Comprehending this circuit complexity requires to identify unknown factors and dissect molecular topographies. Glia contribute to both aspects and certain studies provide molecular and functional insights into these contributions. Here, I survey glial roles in guiding axon navigation in vivo, emphasizing analogies, differences and open questions across major genetic models. I highlight studies pioneering the topic, and dissect recent findings that further advance our current molecular understanding. Circuits of the vertebrate forebrain, visual system and neural tube in zebrafish, mouse and chick, the Drosophila ventral cord and the C. elegans brain-like neuropil emerge as major contexts to study glial cell functions in axon navigation. I present astroglial cell types in these models, and their molecular and cellular interactions that drive axon guidance. I underline shared principles across models, conceptual or technical complications, and open questions that await investigation. Glia of the radial-astrocyte lineage, emerge as regulators of axon pathfinding, often employing common molecular factors across models. Yet this survey also highlights different involvements of glia in embryonic navigation or pioneer axon pathfinding, and unknowns in the molecular underpinnings of glial cell functions. Future cellular and molecular investigations should complete the comprehensive view of glial roles in circuit assembly.
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Affiliation(s)
- Georgia Rapti
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Rome, Italy
- Interdisciplinary Center of Neurosciences, Heidelberg University, Heidelberg, Germany
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6
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Shi L, Hong G, Chen C, Li X, Zhang H, Chai R, Sun D. Growth of spiral ganglion neurons induced by graphene oxide/oxidized bacterial cellulose composite hydrogel. Carbohydr Polym 2023; 311:120749. [PMID: 37028876 DOI: 10.1016/j.carbpol.2023.120749] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 03/06/2023]
Abstract
The damage or degeneration of spiral ganglion neurons (SGNs) can impair the auditory signals transduction from hair cells to the central auditory system, and cause significant hearing loss. Herein, a new form of bioactive hydrogel incorporating topological graphene oxide (GO) and TEMPO-oxidized bacterial cellulose (GO/TOBC hydrogel) was developed to provide a favorable microenvironment for SGN neurite outgrowth. As the network structure of lamellar interspersed fiber cross-linked by GO/TOBC hydrogels well simulated the structure and morphology of ECM, with the controllable hydrophilic property and appropriate Young's modulus well met those requirements of SGNs microenvironment, the GO/TOBC hybrid matrix exhibited great potential to promote the growth of SGNs. The quantitative real-time PCR result confirmed that the GO/TOBC hydrogel can significantly accelerate the development of growth cones and filopodia, by increasing the mRNA expression levels of diap3, fscn2, and integrin β1. These results suggest that GO/TOBC hydrogel scaffolds have the potential to be used to construct biomimetic nerve grafts for repairing or replacing nerve defects.
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Affiliation(s)
- Lin Shi
- Institute of Chemicobiology and Functional Materials, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Street, Nanjing 210094, Jiangsu Province, China
| | - Guodong Hong
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Chuntao Chen
- Institute of Chemicobiology and Functional Materials, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Street, Nanjing 210094, Jiangsu Province, China.
| | - Xueqian Li
- Institute of Chemicobiology and Functional Materials, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Street, Nanjing 210094, Jiangsu Province, China
| | - Heng Zhang
- Institute of Chemicobiology and Functional Materials, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Street, Nanjing 210094, Jiangsu Province, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China.
| | - Dongping Sun
- Institute of Chemicobiology and Functional Materials, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Street, Nanjing 210094, Jiangsu Province, China.
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7
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Gordon H, Schafer ZT, Smith CJ. A paradox promoted by microglia cannibalism shortens the lifespan of developmental microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532426. [PMID: 36993267 PMCID: PMC10055159 DOI: 10.1101/2023.03.15.532426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The overproduction of cells and subsequent production of debris is a universal principle of neurodevelopment. Here we show an additional feature of the developing nervous system that causes neural debris - promoted by the sacrificial nature of embryonic microglia that irreversibly become phagocytic after clearing other neural debris. Described as long-lived, microglia colonize the embryonic brain and persist into adulthood. Using transgenic zebrafish to investigate the microglia debris during brain construction, we identified that unlike other neural cell-types that die in developmental stages after they have expanded, necroptotic-dependent microglial debris is prevalent when microglia are expanding in the zebrafish brain. Time-lapse imaging of microglia demonstrates that this debris is cannibalized by other microglia. To investigate features that promote microglia death and cannibalism, we used time-lapse imaging and fate-mapping strategies to track the lifespan of individual developmental microglia. These approaches revealed that instead of embryonic microglia being long-lived cells that completely digest their phagocytic debris, once most developmental microglia in zebrafish become phagocytic they eventually die, including ones that are cannibalistic. These results establish a paradox -- which we tested by increasing neural debris and manipulating phagocytosis -- that once most microglia in the embryo become phagocytic, they die, create debris and then are cannibalized by other microglia, resulting in more phagocytic microglia that are destined to die.
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Affiliation(s)
- Hannah Gordon
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
- The Center for Stem Cells and Regenerative Medicine at the University of Notre Dame, Notre Dame, IN
| | - Zachary T. Schafer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
| | - Cody J. Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
- The Center for Stem Cells and Regenerative Medicine at the University of Notre Dame, Notre Dame, IN
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8
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Dumoulin A, Stoeckli ET. Looking for Guidance - Models and Methods to Study Axonal Navigation. Neuroscience 2023; 508:30-39. [PMID: 35940454 DOI: 10.1016/j.neuroscience.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 01/17/2023]
Abstract
The molecular mechanisms of neural circuit formation have been of interest to Santiago Ramón y Cajal and thousands of neuroscientists sharing his passion for neural circuits ever since. Cajal was a brilliant observer and taught us about the connections and the morphology of neurons in the adult and developing nervous system. Clearly, we will not learn about molecular mechanisms by just looking at brain sections or cells in culture. Technically, we had to come a long way to today's possibilities that allow us to perturb target gene expression and watch the consequences of our manipulations on navigating axons in situ. In this review, we summarize landmark steps towards modern live-imaging approaches used to study the molecular basis of axon guidance.
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Affiliation(s)
- Alexandre Dumoulin
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Esther T Stoeckli
- Department of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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9
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Martins LF, Brambilla I, Motta A, de Pretis S, Bhat GP, Badaloni A, Malpighi C, Amin ND, Imai F, Almeida RD, Yoshida Y, Pfaff SL, Bonanomi D. Motor neurons use push-pull signals to direct vascular remodeling critical for their connectivity. Neuron 2022; 110:4090-4107.e11. [PMID: 36240771 PMCID: PMC10316999 DOI: 10.1016/j.neuron.2022.09.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 07/19/2022] [Accepted: 09/15/2022] [Indexed: 11/06/2022]
Abstract
The nervous system requires metabolites and oxygen supplied by the neurovascular network, but this necessitates close apposition of neurons and endothelial cells. We find motor neurons attract vessels with long-range VEGF signaling, but endothelial cells in the axonal pathway are an obstacle for establishing connections with muscles. It is unclear how this paradoxical interference from heterotypic neurovascular contacts is averted. Through a mouse mutagenesis screen, we show that Plexin-D1 receptor is required in endothelial cells for development of neuromuscular connectivity. Motor neurons release Sema3C to elicit short-range repulsion via Plexin-D1, thus displacing endothelial cells that obstruct axon growth. When this signaling pathway is disrupted, epaxial motor neurons are blocked from reaching their muscle targets and concomitantly vascular patterning in the spinal cord is altered. Thus, an integrative system of opposing push-pull cues ensures detrimental axon-endothelial encounters are avoided while enabling vascularization within the nervous system and along peripheral nerves.
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Affiliation(s)
- Luis F Martins
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy; CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal
| | - Ilaria Brambilla
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Alessia Motta
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Stefano de Pretis
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy; Center for Omics Sciences, San Raffaele Scientific Institute, Milan, Italy
| | - Ganesh Parameshwar Bhat
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Aurora Badaloni
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Chiara Malpighi
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Neal D Amin
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Fumiyasu Imai
- Burke Neurological Institute, White Plains, NY 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ramiro D Almeida
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal; iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro 3810-193, Portugal
| | - Yutaka Yoshida
- Burke Neurological Institute, White Plains, NY 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA; Neural Circuit Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Samuel L Pfaff
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA.
| | - Dario Bonanomi
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy.
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10
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Green LA, O'Dea MR, Hoover CA, DeSantis DF, Smith CJ. The embryonic zebrafish brain is seeded by a lymphatic-dependent population of mrc1 + microglia precursors. Nat Neurosci 2022; 25:849-864. [PMID: 35710983 PMCID: PMC10680068 DOI: 10.1038/s41593-022-01091-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/06/2022] [Indexed: 02/02/2023]
Abstract
Microglia are the resident macrophages of the CNS that serve critical roles in brain construction. Although human brains contain microglia by 4 weeks gestation, an understanding of the earliest microglia that seed the brain during its development remains unresolved. Using time-lapse imaging in zebrafish, we discovered a mrc1a+ microglia precursor population that seeds the brain before traditionally described microglia. These early microglia precursors are dependent on lymphatic vasculature that surrounds the brain and are independent of pu1+ yolk sac-derived microglia. Single-cell RNA-sequencing datasets reveal Mrc1+ microglia in the embryonic brains of mice and humans. We then show in zebrafish that these early mrc1a+ microglia precursors preferentially expand during pathophysiological states in development. Taken together, our results identify a critical role of lymphatics in the microglia precursors that seed the early embryonic brain.
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Affiliation(s)
- Lauren A Green
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
- The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA
| | - Michael R O'Dea
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Camden A Hoover
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
- The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA
| | - Dana F DeSantis
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
- The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA
| | - Cody J Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
- The Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA.
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11
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Garde A, Kenny IW, Kelley LC, Chi Q, Mutlu AS, Wang MC, Sherwood DR. Localized glucose import, glycolytic processing, and mitochondria generate a focused ATP burst to power basement-membrane invasion. Dev Cell 2022; 57:732-749.e7. [PMID: 35316617 PMCID: PMC8969095 DOI: 10.1016/j.devcel.2022.02.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 01/18/2022] [Accepted: 02/18/2022] [Indexed: 11/27/2022]
Abstract
Invasive cells use transient, energy-consuming protrusions to breach basement membrane (BM) barriers. Using the ATP sensor PercevalHR during anchor cell (AC) invasion in Caenorhabditis elegans, we show that BM invasion is accompanied by an ATP burst from mitochondria at the invasive front. RNAi screening and visualization of a glucose biosensor identified two glucose transporters, FGT-1 and FGT-2, which bathe invasive front mitochondria with glucose and facilitate the ATP burst to form protrusions. FGT-1 localizes at high levels along the invasive membrane, while FGT-2 is adaptive, enriching most strongly during BM breaching and when FGT-1 is absent. Cytosolic glycolytic enzymes that process glucose for mitochondrial ATP production cluster with invasive front mitochondria and promote higher mitochondrial membrane potential and ATP levels. Finally, we show that UNC-6 (netrin), which polarizes invasive protrusions, also orients FGT-1. These studies reveal a robust and integrated energy acquisition, processing, and delivery network that powers BM breaching.
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Affiliation(s)
- Aastha Garde
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27708, USA
| | - Isabel W Kenny
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
| | - Laura C Kelley
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
| | - Qiuyi Chi
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
| | - Ayse Sena Mutlu
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng C Wang
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - David R Sherwood
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA.
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12
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Kikel-Coury NL, Brandt JP, Correia IA, O’Dea MR, DeSantis DF, Sterling F, Vaughan K, Ozcebe G, Zorlutuna P, Smith CJ. Identification of astroglia-like cardiac nexus glia that are critical regulators of cardiac development and function. PLoS Biol 2021; 19:e3001444. [PMID: 34793438 PMCID: PMC8601506 DOI: 10.1371/journal.pbio.3001444] [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: 04/16/2021] [Accepted: 10/18/2021] [Indexed: 01/09/2023] Open
Abstract
Glial cells are essential for functionality of the nervous system. Growing evidence underscores the importance of astrocytes; however, analogous astroglia in peripheral organs are poorly understood. Using confocal time-lapse imaging, fate mapping, and mutant genesis in a zebrafish model, we identify a neural crest-derived glial cell, termed nexus glia, which utilizes Meteorin signaling via Jak/Stat3 to drive differentiation and regulate heart rate and rhythm. Nexus glia are labeled with gfap, glast, and glutamine synthetase, markers that typically denote astroglia cells. Further, analysis of single-cell sequencing datasets of human and murine hearts across ages reveals astrocyte-like cells, which we confirm through a multispecies approach. We show that cardiac nexus glia at the outflow tract are critical regulators of both the sympathetic and parasympathetic system. These data establish the crucial role of glia on cardiac homeostasis and provide a description of nexus glia in the PNS.
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Affiliation(s)
- Nina L. Kikel-Coury
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Jacob P. Brandt
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Isabel A. Correia
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Michael R. O’Dea
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Dana F. DeSantis
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Felicity Sterling
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Kevin Vaughan
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Gulberk Ozcebe
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Pinar Zorlutuna
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Cody J. Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America
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13
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Weaver CJ, Poulain FE. From whole organism to ultrastructure: progress in axonal imaging for decoding circuit development. Development 2021; 148:271122. [PMID: 34328171 DOI: 10.1242/dev.199717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Since the pioneering work of Ramón y Cajal, scientists have sought to unravel the complexities of axon development underlying neural circuit formation. Micrometer-scale axonal growth cones navigate to targets that are often centimeters away. To reach their targets, growth cones react to dynamic environmental cues that change in the order of seconds to days. Proper axon growth and guidance are essential to circuit formation, and progress in imaging has been integral to studying these processes. In particular, advances in high- and super-resolution microscopy provide the spatial and temporal resolution required for studying developing axons. In this Review, we describe how improved microscopy has revolutionized our understanding of axonal development. We discuss how novel technologies, specifically light-sheet and super-resolution microscopy, led to new discoveries at the cellular scale by imaging axon outgrowth and circuit wiring with extreme precision. We next examine how advanced microscopy broadened our understanding of the subcellular dynamics driving axon growth and guidance. We finally assess the current challenges that the field of axonal biology still faces for imaging axons, and examine how future technology could meet these needs.
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Affiliation(s)
- Cory J Weaver
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Fabienne E Poulain
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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14
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Pioneer Axons Utilize a Dcc Signaling-Mediated Invasion Brake to Precisely Complete Their Pathfinding Odyssey. J Neurosci 2021; 41:6617-6636. [PMID: 34131031 DOI: 10.1523/jneurosci.0212-21.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 11/21/2022] Open
Abstract
Axons navigate through the embryo to construct a functional nervous system. A missing part of the axon navigation puzzle is how a single axon traverses distinct anatomic choice points through its navigation. The dorsal root ganglia (DRG) neurons experience such choice points. First, they navigate to the dorsal root entry zone (DREZ), then halt navigation in the peripheral nervous system to invade the spinal cord, and then reinitiate navigation inside the CNS. Here, we used time-lapse super-resolution imaging in zebrafish DRG pioneer neurons to investigate how embryonic axons control their cytoskeleton to navigate to and invade at the correct anatomic position. We found that invadopodia components form in the growth cone even during filopodia-based navigation, but only stabilize when the axon is at the spinal cord entry location. Further, we show that intermediate levels of DCC and cAMP, as well as Rac1 activation, subsequently engage an axon invasion brake. Our results indicate that actin-based invadopodia components form in the growth cone and disruption of the invasion brake causes axon entry defects and results in failed behavioral responses, thereby demonstrating the importance of regulating distinct actin populations during navigational challenges.SIGNIFICANCE STATEMENT Correct spatiotemporal navigation of neuronal growth cones is dependent on extracellular navigational cues and growth cone dynamics. Here, we link dcc-mediated signaling to actin-based invadopodia and filopodia dynamics during pathfinding and entry into the spinal cord using an in vivo model of dorsal root ganglia (DRG) sensory axons. We reveal a molecularly-controlled brake on invadopodia stabilization until the sensory neuron growth cone is present at the dorsal root entry zone (DREZ), which is ultimately essential for growth cone entry into the spinal cord and behavioral response.
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15
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Yin C, Peterman E, Rasmussen JP, Parrish JZ. Transparent Touch: Insights From Model Systems on Epidermal Control of Somatosensory Innervation. Front Cell Neurosci 2021; 15:680345. [PMID: 34135734 PMCID: PMC8200473 DOI: 10.3389/fncel.2021.680345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 04/28/2021] [Indexed: 12/28/2022] Open
Abstract
Somatosensory neurons (SSNs) densely innervate our largest organ, the skin, and shape our experience of the world, mediating responses to sensory stimuli including touch, pressure, and temperature. Historically, epidermal contributions to somatosensation, including roles in shaping innervation patterns and responses to sensory stimuli, have been understudied. However, recent work demonstrates that epidermal signals dictate patterns of SSN skin innervation through a variety of mechanisms including targeting afferents to the epidermis, providing instructive cues for branching morphogenesis, growth control and structural stability of neurites, and facilitating neurite-neurite interactions. Here, we focus onstudies conducted in worms (Caenorhabditis elegans), fruit flies (Drosophila melanogaster), and zebrafish (Danio rerio): prominent model systems in which anatomical and genetic analyses have defined fundamental principles by which epidermal cells govern SSN development.
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Affiliation(s)
| | | | | | - Jay Z. Parrish
- Department of Biology, University of Washington, Seattle, WA, United States
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16
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Onesto MM, Short CA, Rempel SK, Catlett TS, Gomez TM. Growth Factors as Axon Guidance Molecules: Lessons From in vitro Studies. Front Neurosci 2021; 15:678454. [PMID: 34093120 PMCID: PMC8175860 DOI: 10.3389/fnins.2021.678454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
Growth cones at the tips of extending axons navigate through developing organisms by probing extracellular cues, which guide them through intermediate steps and onto final synaptic target sites. Widespread focus on a few guidance cue families has historically overshadowed potentially crucial roles of less well-studied growth factors in axon guidance. In fact, recent evidence suggests that a variety of growth factors have the ability to guide axons, affecting the targeting and morphogenesis of growth cones in vitro. This review summarizes in vitro experiments identifying responses and signaling mechanisms underlying axon morphogenesis caused by underappreciated growth factors.
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Affiliation(s)
| | | | | | | | - Timothy M. Gomez
- Neuroscience Training Program and Cell and Molecular Biology Program, Department of Neuroscience, University of Wisconsin–Madison, Madison, WI, United States
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17
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Dumoulin A, Zuñiga NR, Stoeckli ET. Axon guidance at the spinal cord midline-A live imaging perspective. J Comp Neurol 2021; 529:2517-2538. [PMID: 33438755 PMCID: PMC8248161 DOI: 10.1002/cne.25107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/10/2020] [Accepted: 01/08/2021] [Indexed: 12/19/2022]
Abstract
During neural circuit formation, axons navigate several choice points to reach their final target. At each one of these intermediate targets, growth cones need to switch responsiveness from attraction to repulsion in order to move on. Molecular mechanisms that allow for the precise timing of surface expression of a new set of receptors that support the switch in responsiveness are difficult to study in vivo. Mostly, mechanisms are inferred from the observation of snapshots of many different growth cones analyzed in different preparations of tissue harvested at distinct time points. However, to really understand the behavior of growth cones at choice points, a single growth cone should be followed arriving at and leaving the intermediate target. Existing ex vivo preparations, like cultures of an “open‐book” preparation of the spinal cord have been successfully used to study floor plate entry and exit, but artifacts prevent the analysis of growth cone behavior at the floor plate exit site. Here, we describe a novel spinal cord preparation that allows for live imaging of individual axons during navigation in their intact environment. When comparing growth cone behavior in our ex vivo system with snapshots from in vivo navigation, we do not see any differences. The possibility to observe the dynamics of single growth cones navigating their intermediate target allows for measuring growth speed, changes in morphology, or aberrant behavior, like stalling and wrong turning. Moreover, observation of the intermediate target—the floor plate—revealed its active participation and interaction with commissural axons during midline crossing.
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Affiliation(s)
- Alexandre Dumoulin
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Nikole R Zuñiga
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Esther T Stoeckli
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
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18
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Nichols EL, Smith CJ. Functional Regeneration of the Sensory Root via Axonal Invasion. Cell Rep 2021; 30:9-17.e3. [PMID: 31914401 PMCID: PMC6996490 DOI: 10.1016/j.celrep.2019.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/15/2019] [Accepted: 12/03/2019] [Indexed: 12/11/2022] Open
Abstract
Regeneration following spinal root avulsion is broadly unsuccessful
despite the regenerative capacity of other PNS-located nerves. By combining
focal laser lesioning to model root avulsion in zebrafish, time-lapse imaging,
and transgenesis, we identify that regenerating DRG neurons fail to recapitulate
developmental paradigms of actin-based invasion after injury. We demonstrate
that inducing actin reorganization into invasive components via pharmacological
and genetic approaches in the regenerating axon can rescue sensory axon spinal
cord entry. Cell-autonomous induction of invasion components using
constitutively active Src induces DRG axon regeneration, suggesting an intrinsic
mechanism can be activated to drive regeneration. Furthermore, analyses of
neuronal activity and animal behavior show restoration of sensory circuit
activity and behavior upon stimulating axons to re-enter the spinal cord via
invasion. Altogether, our data identify induction of invasive components as
sufficient for functional sensory root regeneration after injury. Dorsal root ganglion (DRG) sensory axons are unable to regenerate into
the spinal cord after injury. Nichols and Smith demonstrate in zebrafish that
injured DRG axons do not initiate actin-based invasion components during
re-entry into the spinal cord. Pharmacological and cell-autonomous genetic
manipulations that promote actin-mediated cell invasion to restore sensory
behavior.
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Affiliation(s)
- Evan L Nichols
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA; Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA
| | - Cody J Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA; Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN, USA.
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19
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Rho GTPases Signaling in Zebrafish Development and Disease. Cells 2020; 9:cells9122634. [PMID: 33302361 PMCID: PMC7762611 DOI: 10.3390/cells9122634] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 02/08/2023] Open
Abstract
Cells encounter countless external cues and the specificity of their responses is translated through a myriad of tightly regulated intracellular signals. For this, Rho GTPases play a central role and transduce signals that contribute to fundamental cell dynamic and survival events. Here, we review our knowledge on how zebrafish helped us understand the role of some of these proteins in a multitude of in vivo cellular behaviors. Zebrafish studies offer a unique opportunity to explore the role and more specifically the spatial and temporal dynamic of Rho GTPases activities within a complex environment at a level of details unachievable in any other vertebrate organism.
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20
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Suter TACS, Jaworski A. Cell migration and axon guidance at the border between central and peripheral nervous system. Science 2020; 365:365/6456/eaaw8231. [PMID: 31467195 DOI: 10.1126/science.aaw8231] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/22/2019] [Indexed: 12/13/2022]
Abstract
The central and peripheral nervous system (CNS and PNS, respectively) are composed of distinct neuronal and glial cell types with specialized functional properties. However, a small number of select cells traverse the CNS-PNS boundary and connect these two major subdivisions of the nervous system. This pattern of segregation and selective connectivity is established during embryonic development, when neurons and glia migrate to their destinations and axons project to their targets. Here, we provide an overview of the cellular and molecular mechanisms that control cell migration and axon guidance at the vertebrate CNS-PNS border. We highlight recent advances on how cell bodies and axons are instructed to either cross or respect this boundary, and present open questions concerning the development and plasticity of the CNS-PNS interface.
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Affiliation(s)
- Tracey A C S Suter
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA.,Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Alexander Jaworski
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA. .,Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
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21
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Nichols EL, Smith CJ. Synaptic-like Vesicles Facilitate Pioneer Axon Invasion. Curr Biol 2019; 29:2652-2664.e4. [DOI: 10.1016/j.cub.2019.06.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/24/2019] [Accepted: 06/26/2019] [Indexed: 12/19/2022]
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22
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Zhang Y, Nichols EL, Zellmer AM, Guldner IH, Kankel C, Zhang S, Howard SS, Smith CJ. Generating intravital super-resolution movies with conventional microscopy reveals actin dynamics that construct pioneer axons. Development 2019; 146:dev.171512. [PMID: 30760484 PMCID: PMC6432666 DOI: 10.1242/dev.171512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 02/04/2019] [Indexed: 01/06/2023]
Abstract
Super-resolution microscopy is broadening our in-depth understanding of cellular structure. However, super-resolution approaches are limited, for numerous reasons, from utilization in longer-term intravital imaging. We devised a combinatorial imaging technique that combines deconvolution with stepwise optical saturation microscopy (DeSOS) to circumvent this issue and image cells in their native physiological environment. Other than a traditional confocal or two-photon microscope, this approach requires no additional hardware. Here, we provide an open-access application to obtain DeSOS images from conventional microscope images obtained at low excitation powers. We show that DeSOS can be used in time-lapse imaging to generate super-resolution movies in zebrafish. DeSOS was also validated in live mice. These movies uncover that actin structures dynamically remodel to produce a single pioneer axon in a ‘top-down’ scaffolding event. Further, we identify an F-actin population – stable base clusters – that orchestrate that scaffolding event. We then identify that activation of Rac1 in pioneer axons destabilizes stable base clusters and disrupts pioneer axon formation. The ease of acquisition and processing with this approach provides a universal technique for biologists to answer questions in living animals. Summary: Actin dynamics are examined in zebrafish axons using DeSOS, a new super-resolution technique combining deconvolution with stepwise optical saturation microscopy that allows detailed intravital imaging of cells in their native environments.
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Affiliation(s)
- Yide Zhang
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Evan L Nichols
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.,Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Abigail M Zellmer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Ian H Guldner
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA.,Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Cody Kankel
- Center for Research Computing. University of Notre Dame, Notre Dame, IN 46556, USA
| | - Siyuan Zhang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA.,Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Scott S Howard
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA .,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Cody J Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA .,Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, IN 46556, USA
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