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Kwokdinata C, Chew SY. Additive manufacturing in spatial patterning for spinal cord injury treatment. Adv Drug Deliv Rev 2025; 218:115523. [PMID: 39880332 DOI: 10.1016/j.addr.2025.115523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2024] [Revised: 01/03/2025] [Accepted: 01/26/2025] [Indexed: 01/31/2025]
Abstract
Combinatorial treatments integrating cells and biomolecules within scaffolds have been investigated to address the multifactorial nature of spinal cord injury (SCI). Current regenerative treatments have been ineffective as they do not consider the spatial positions of various cell types to effectively form functional neural pathways. Emulating the complex heterogeneity of cells in the native spinal cord requires translating the existing biological understanding of spatial patterning in neural development, as well as the influence of biomolecule and mechanical patterning on regional specification and axonal regeneration, to engineer a scaffold for spinal cord regeneration. This review explores the potential of 3D bioprinting to precisely control material, cell and drug patterns in scaffolds, achieving spatial phenotype specification and providing axonal guidance to form appropriate connections. We also discuss the application of extrusion-based and digital light processing bioprinting in integrating mechanical, chemical and biological cues within a scaffold to advance spatially patterned 3D bioprinted scaffold, as well as current challenges and future perspectives in these bioengineering strategies.
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Affiliation(s)
- Christy Kwokdinata
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 637459 Singapore
| | - Sing Yian Chew
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 637459 Singapore; Critical Analytics for Manufacturing Personalized-Medicine Interdisciplinary Research Group, Singapore-MIT Alliance for Research & Technology, Campus for Research Excellence and Technological Enterprise 138602 Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University 308232 Singapore; School of Materials Science and Engineering 639798 Singapore; National Neuroscience Institute, 11 Jalan Tan Tock Seng 308433 Singapore.
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2
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Siliciano AF, Minni S, Morton C, Dowell CK, Eghbali NB, Rhee JY, Abbott L, Ruta V. A vector-based strategy for olfactory navigation in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.15.638426. [PMID: 39990408 PMCID: PMC11844514 DOI: 10.1101/2025.02.15.638426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/25/2025]
Abstract
Odors serve as essential cues for navigation. Although tracking an odor plume has been modeled as a reflexive process, it remains unclear whether animals can use memories of their past odor encounters to infer the spatial structure of their chemical environment or their location within it. Here we developed a virtual-reality olfactory paradigm that allows head-fixed Drosophila to navigate structured chemical landscapes, offering insight into how memory mechanisms shape their navigational strategies. We found that flies track an appetitive odor corridor by following its boundary, alternating between rapid counterturns to exit the plume and directed returns to its edge. Using a combination of behavioral modeling, functional calcium imaging, and neural perturbations, we demonstrate that this 'edge-tracking' strategy relies on vector-based computations within the Drosophila central complex in which flies store and dynamically update memories of the direction to return them to the plume's boundary. Consistent with this, we find that FC2 neurons within the fan-shaped body, which encode a fly's navigational goal, signal the direction back to the odor boundary when flies are outside the plume. Together, our studies suggest that flies leverage the plume's boundary as a dynamic landmark to guide their navigation, analogous to the memory-based strategies other insects use for long-distance migration or homing to their nests. Plume tracking thus uses components of a conserved navigational toolkit, enabling flies to use memory mechanisms to navigate through a complex shifting chemical landscape.
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Affiliation(s)
- Andrew F. Siliciano
- These authors contributed equally to this work
- Laboratory of Neurophysiology and Behavior and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Sun Minni
- These authors contributed equally to this work
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, Department of Neuroscience, Columbia University, New York, NY, USA
| | - Chad Morton
- These authors contributed equally to this work
- Laboratory of Neurophysiology and Behavior and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Charles K. Dowell
- Laboratory of Neurophysiology and Behavior and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Noelle B. Eghbali
- Laboratory of Neurophysiology and Behavior and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Juliana Y. Rhee
- Laboratory of Neurophysiology and Behavior and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - L.F. Abbott
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, Department of Neuroscience, Columbia University, New York, NY, USA
| | - Vanessa Ruta
- Laboratory of Neurophysiology and Behavior and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
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3
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Knight J, García-Galindo P, Pausch J, Pruessner G. Memoryless chemotaxis with discrete cues. J R Soc Interface 2024; 21:20240100. [PMID: 39081250 PMCID: PMC11289677 DOI: 10.1098/rsif.2024.0100] [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: 02/09/2024] [Revised: 05/06/2024] [Accepted: 06/24/2024] [Indexed: 08/02/2024] Open
Abstract
Biological systems such as axonal growth cones perform chemotaxis at micrometre-level length scales, where chemotactic molecules are sparse. Such systems lie outside the range of validity of existing models, which assume smoothly varying chemical gradients. We investigate the effect of introducing discrete chemoattractant molecules by constructing a minimal dynamical model consisting of a chemotactic cell without internal memory. Significant differences are found in the behaviour of the cell as the chemical gradient is changed from smoothly varying to discrete, including the emergence of a homing radius beyond which chemotaxis is not reliably performed.
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Affiliation(s)
- Jacob Knight
- Department of Mathematics, Imperial College London, South Kensington, LondonSW7 2BZ, UK
| | - Paula García-Galindo
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, CambridgeCB3 0AS, UK
| | - Johannes Pausch
- Department of Mathematics, Imperial College London, South Kensington, LondonSW7 2BZ, UK
| | - Gunnar Pruessner
- Department of Mathematics, Imperial College London, South Kensington, LondonSW7 2BZ, UK
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4
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Washburn HR, Chander P, Srikanth KD, Dalva MB. Transsynaptic Signaling of Ephs in Synaptic Development, Plasticity, and Disease. Neuroscience 2023; 508:137-152. [PMID: 36460219 DOI: 10.1016/j.neuroscience.2022.11.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022]
Abstract
Synapse formation between neurons is critical for proper circuit and brain function. Prior to activity-dependent refinement of connections between neurons, activity-independent cues regulate the contact and recognition of potential synaptic partners. Formation of a synapse results in molecular recognition events that initiate the process of synaptogenesis. Synaptogenesis requires contact between axon and dendrite, selection of correct and rejection of incorrect partners, and recruitment of appropriate pre- and postsynaptic proteins needed for the establishment of functional synaptic contact. Key regulators of these events are families of transsynaptic proteins, where one protein is found on the presynaptic neuron and the other is found on the postsynaptic neuron. Of these families, the EphBs and ephrin-Bs are required during each phase of synaptic development from target selection, recruitment of synaptic proteins, and formation of spines to regulation of synaptic plasticity at glutamatergic spine synapses in the mature brain. These roles also place EphBs and ephrin-Bs as important regulators of human neurological diseases. This review will focus on the role of EphBs and ephrin-Bs at synapses.
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Affiliation(s)
- Halley R Washburn
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA; Department of Neuroscience, Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10th Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Praveen Chander
- Department of Neuroscience, Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10th Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Kolluru D Srikanth
- Department of Neuroscience, Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10th Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Matthew B Dalva
- Department of Neuroscience, Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10th Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA.
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5
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Bang S, Hwang KS, Jeong S, Cho IJ, Choi N, Kim J, Kim HN. Engineered neural circuits for modeling brain physiology and neuropathology. Acta Biomater 2021; 132:379-400. [PMID: 34157452 DOI: 10.1016/j.actbio.2021.06.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/16/2021] [Accepted: 06/14/2021] [Indexed: 12/14/2022]
Abstract
The neural circuits of the central nervous system are the regulatory pathways for feeling, motion control, learning, and memory, and their dysfunction is closely related to various neurodegenerative diseases. Despite the growing demand for the unraveling of the physiology and functional connectivity of the neural circuits, their fundamental investigation is hampered because of the inability to access the components of neural circuits and the complex microenvironment. As an alternative approach, in vitro human neural circuits show principles of in vivo human neuronal circuit function. They allow access to the cellular compartment and permit real-time monitoring of neural circuits. In this review, we summarize recent advances in reconstituted in vitro neural circuits using engineering techniques. To this end, we provide an overview of the fabrication techniques and methods for stimulation and measurement of in vitro neural circuits. Subsequently, representative examples of in vitro neural circuits are reviewed with a particular focus on the recapitulation of structures and functions observed in vivo, and we summarize their application in the study of various brain diseases. We believe that the in vitro neural circuits can help neuroscience and the neuropharmacology. STATEMENT OF SIGNIFICANCE: Despite the growing demand to unravel the physiology and functional connectivity of the neural circuits, the studies on the in vivo neural circuits are frequently limited due to the poor accessibility. Furthermore, single neuron-based analysis has an inherent limitation in that it does not reflect the full spectrum of the neural circuit physiology. As an alternative approach, in vitro engineered neural circuit models have arisen because they can recapitulate the structural and functional characteristics of in vivo neural circuits. These in vitro neural circuits allow the mimicking of dysregulation of the neural circuits, including neurodegenerative diseases and traumatic brain injury. Emerging in vitro engineered neural circuits will provide a better understanding of the (patho-)physiology of neural circuits.
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Affiliation(s)
- Seokyoung Bang
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Kyeong Seob Hwang
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Sohyeon Jeong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea
| | - Il-Joo Cho
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea; School of Electrical and Electronics Engineering, Yonsei University, Seoul 03722, Republic of Korea; Yonsei-KIST Convergence Research Institute, Yonsei University, Seoul 03722, Republic of Korea
| | - Nakwon Choi
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea.
| | - Jongbaeg Kim
- School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Hong Nam Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea.
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6
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Seo J, Youn W, Choi JY, Cho H, Choi H, Lanara C, Stratakis E, Choi IS. Neuro-taxis: Neuronal movement in gradients of chemical and physical environments. Dev Neurobiol 2020; 80:361-377. [PMID: 32304173 DOI: 10.1002/dneu.22749] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 04/13/2020] [Indexed: 12/15/2022]
Abstract
Environmental chemical and physical cues dynamically interact with migrating neurons and sprouting axons, and in particular, the gradients of environmental cues are regarded as one of the factors intimately involved in the neuronal movement. Since a growth cone was first described by Cajal, more than one century ago, chemical gradients have been suggested as one of the mechanisms by which the neurons determine proper paths and destinations. However, the gradients of physical cues, such as stiffness and topography, which also interact constantly with the neurons and their axons as a component of the extracellular environments, have rarely been noted regarding the guidance of neurons, despite their gradually increasingly reported influences in the case of nonneuronal-cell migration. In this review, we discuss chemical (i.e., chemo- and hapto-) and physical (i.e., duro-) taxis phenomena on the movement of neurons including axonal elongation. In addition, we suggest topotaxis, the most recently proposed physical-taxis phenomenon, as another potential mechanism in the neuronal movement, based on the reports of neuronal recognition of and responses to nanotopography.
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Affiliation(s)
| | - Wongu Youn
- Department of Chemistry, KAIST, Daejeon, Korea
| | - Ji Yu Choi
- Department of Chemistry, KAIST, Daejeon, Korea
| | | | | | - Christina Lanara
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete, Greece
| | - Emmanuel Stratakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete, Greece.,Physics Department, University of Crete, Heraklion, Crete, Greece
| | - Insung S Choi
- Department of Chemistry, KAIST, Daejeon, Korea.,Department of Bio and Brain Engineering, KAIST, Daejeon, Korea
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7
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Courtine G, Sofroniew MV. Spinal cord repair: advances in biology and technology. Nat Med 2019; 25:898-908. [PMID: 31160817 DOI: 10.1038/s41591-019-0475-6] [Citation(s) in RCA: 313] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
Individuals with spinal cord injury (SCI) can face decades with permanent disabilities. Advances in clinical management have decreased morbidity and improved outcomes, but no randomized clinical trial has demonstrated the efficacy of a repair strategy for improving recovery from SCI. Here, we summarize recent advances in biological and engineering strategies to augment neuroplasticity and/or functional recovery in animal models of SCI that are pushing toward clinical translation.
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Affiliation(s)
- Grégoire Courtine
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland. .,Department of Neurosurgery, University Hospital Lausanne (CHUV), Lausanne, Switzerland.
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
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8
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Baba K, Yoshida W, Toriyama M, Shimada T, Manning CF, Saito M, Kohno K, Trimmer JS, Watanabe R, Inagaki N. Gradient-reading and mechano-effector machinery for netrin-1-induced axon guidance. eLife 2018; 7:34593. [PMID: 30082022 PMCID: PMC6080949 DOI: 10.7554/elife.34593] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/05/2018] [Indexed: 12/28/2022] Open
Abstract
Growth cones navigate axonal projection in response to guidance cues. However, it is unclear how they can decide the migratory direction by transducing the local spatial cues into protrusive forces. Here we show that knockout mice of Shootin1 display abnormal projection of the forebrain commissural axons, a phenotype similar to that of the axon guidance molecule netrin-1. Shallow gradients of netrin-1 elicited highly polarized Pak1-mediated phosphorylation of shootin1 within growth cones. We demonstrate that netrin-1–elicited shootin1 phosphorylation increases shootin1 interaction with the cell adhesion molecule L1-CAM; this, in turn, promotes F-actin–adhesion coupling and concomitant generation of forces for growth cone migration. Moreover, the spatially regulated shootin1 phosphorylation within growth cones is required for axon turning induced by netrin-1 gradients. Our study defines a mechano-effector for netrin-1 signaling and demonstrates that shootin1 phosphorylation is a critical readout for netrin-1 gradients that results in a directional mechanoresponse for axon guidance. Neurons communicate with each other by forming intricate webs that link cells together according to a precise pattern. A neuron can connect to another by growing a branch-like structure known as the axon. To contact the correct neuron, the axon must develop and thread its way to exactly the right place in the brain. Scientists know that the tip of the axon is extraordinarily sensitive to gradients of certain molecules in its surroundings, which guide the budding structure towards its final destination. In particular, two molecules seem to play an important part in this process: netrin-1, which is a protein found outside cells that attracts a growing axon, and shootin1a, which is present inside neurons. Previous studies have shown that netrin-1 can trigger a cascade of reactions that activates shootin1a. In turn, activated shootin1a molecules join the internal skeleton of the cell with L1-CAM, a molecule that attaches the neuron to its surroundings. If the internal skeleton is the engine of the axon, L1-CAMs are the wheels, and shootin1a the clutch. However, it is not clear whether shootin1a is involved in guiding growing axons, and how it could help neurons ‘understand’ and react to gradients of netrin-1. Here, Baba et al. discover that when shootin1a is absent in mice, the axons do not develop properly. Further experiments in rat neurons show that if there is a little more netrin-1 on one side of the tip of an axon, this switches on the shootin1a molecules on that edge. Activated shootin1a promote interactions between the internal skeleton and L1-CAM, helping the axon curve towards the area that has more netrin-1. In fact, if the activated shootin1a is present everywhere on the axon, and not just on one side, the structure can develop, but not turn. Taken together, the results suggest that shootin1a can read the gradients of netrin-1 and then coordinate the turning of a growing axon in response. Wound healing, immune responses or formation of organs are just a few examples of processes that rely on cells moving in an orderly manner through the body. Dissecting how axons are guided through their development may shed light on the migration of cells in general. Ultimately, this could help scientists to understand disorders such as birth abnormalities or neurological disabilities, which arise when this process goes awry.
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Affiliation(s)
- Kentarou Baba
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Wataru Yoshida
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Michinori Toriyama
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Tadayuki Shimada
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Colleen F Manning
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| | - Michiko Saito
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Kenji Kohno
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - James S Trimmer
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| | - Rikiya Watanabe
- Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, Tokyo, Japan
| | - Naoyuki Inagaki
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
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9
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Limerick G, Tang X, Lee WS, Mohamed A, Al-Aamiri A, Wadsworth WG. A Statistically-Oriented Asymmetric Localization (SOAL) Model for Neuronal Outgrowth Patterning by Caenorhabditis elegans UNC-5 (UNC5) and UNC-40 (DCC) Netrin Receptors. Genetics 2018; 208:245-272. [PMID: 29092889 PMCID: PMC5753861 DOI: 10.1534/genetics.117.300460] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 10/29/2017] [Indexed: 01/01/2023] Open
Abstract
Neurons extend processes that vary in number, length, and direction of "outgrowth". Extracellular cues help determine outgrowth patterns. In Caenorhabditis elegans, neurons respond to the extracellular UNC-6 (netrin) cue via UNC-40 (DCC) and UNC-5 (UNC5) receptors. Previously, we presented evidence that UNC-40 asymmetric localization at the plasma membrane is self-organizing, and that UNC-40 can localize and mediate outgrowth at randomly selected sites. Here, we provide further evidence for a statistically-oriented asymmetric localization (SOAL) model in which UNC-5 receptor activity affects patterns of axon outgrowth by regulating UNC-40 asymmetric localization. According to the SOAL model, the direction of outgrowth activity fluctuates across the membrane over time. Random walk modeling predicts that increasing the degree to which the direction of outgrowth fluctuates will decrease the outward displacement of the membrane. By differentially affecting the degree to which the direction of outgrowth activity fluctuates over time, extracellular cues can produce different rates of outgrowth along the surface and create patterns of "extension". Consistent with the SOAL model, we show that unc-5 mutations alter UNC-40 asymmetric localization, increase the degree to which the direction of outgrowth fluctuates, and reduce the extent of outgrowth in multiple directions relative to the source of UNC-6 These results are inconsistent with current models, which predict that UNC-5 mediates a "repulsive" response to UNC-6 Genetic interactions suggest that UNC-5 acts through the UNC-53 (NAV2) cytoplasmic protein to regulate UNC-40 asymmetric localization in response to both the UNC-6 and EGL-20 (Wnt) extracellular cues.
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Affiliation(s)
- Gerard Limerick
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Xia Tang
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Won Suk Lee
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Ahmed Mohamed
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Aseel Al-Aamiri
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - William G Wadsworth
- Department of Pathology and Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
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10
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Revisiting chemoaffinity theory: Chemotactic implementation of topographic axonal projection. PLoS Comput Biol 2017; 13:e1005702. [PMID: 28792499 PMCID: PMC5562328 DOI: 10.1371/journal.pcbi.1005702] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/18/2017] [Accepted: 07/25/2017] [Indexed: 01/18/2023] Open
Abstract
Neural circuits are wired by chemotactic migration of growth cones guided by extracellular guidance cue gradients. How growth cone chemotaxis builds the macroscopic structure of the neural circuit is a fundamental question in neuroscience. I addressed this issue in the case of the ordered axonal projections called topographic maps in the retinotectal system. In the retina and tectum, the erythropoietin-producing hepatocellular (Eph) receptors and their ligands, the ephrins, are expressed in gradients. According to Sperry's chemoaffinity theory, gradients in both the source and target areas enable projecting axons to recognize their proper terminals, but how axons chemotactically decode their destinations is largely unknown. To identify the chemotactic mechanism of topographic mapping, I developed a mathematical model of intracellular signaling in the growth cone that focuses on the growth cone's unique chemotactic property of being attracted or repelled by the same guidance cues in different biological situations. The model presented mechanism by which the retinal growth cone reaches the correct terminal zone in the tectum through alternating chemotactic response between attraction and repulsion around a preferred concentration. The model also provided a unified understanding of the contrasting relationships between receptor expression levels and preferred ligand concentrations in EphA/ephrinA- and EphB/ephrinB-encoded topographic mappings. Thus, this study redefines the chemoaffinity theory in chemotactic terms.
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11
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Abstract
Spinal cord injury (SCI) lesions present diverse challenges for repair strategies. Anatomically complete injuries require restoration of neural connectivity across lesions. Anatomically incomplete injuries may benefit from augmentation of spontaneous circuit reorganization. Here, we review SCI cell biology, which varies considerably across three different lesion-related tissue compartments: (a) non-neural lesion core, (b) astrocyte scar border, and (c) surrounding spared but reactive neural tissue. After SCI, axon growth and circuit reorganization are determined by neuron-cell-autonomous mechanisms and by interactions among neurons, glia, and immune and other cells. These interactions are shaped by both the presence and the absence of growth-modulating molecules, which vary markedly in different lesion compartments. The emerging understanding of how SCI cell biology differs across lesion compartments is fundamental to developing rationally targeted repair strategies.
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12
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Fiederling F, Weschenfelder M, Fritz M, von Philipsborn A, Bastmeyer M, Weth F. Ephrin-A/EphA specific co-adaptation as a novel mechanism in topographic axon guidance. eLife 2017; 6. [PMID: 28722651 PMCID: PMC5517148 DOI: 10.7554/elife.25533] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 06/26/2017] [Indexed: 12/30/2022] Open
Abstract
Genetic hardwiring during brain development provides computational architectures for innate neuronal processing. Thus, the paradigmatic chick retinotectal projection, due to its neighborhood preserving, topographic organization, establishes millions of parallel channels for incremental visual field analysis. Retinal axons receive targeting information from quantitative guidance cue gradients. Surprisingly, novel adaptation assays demonstrate that retinal growth cones robustly adapt towards ephrin-A/EphA forward and reverse signals, which provide the major mapping cues. Computational modeling suggests that topographic accuracy and adaptability, though seemingly incompatible, could be reconciled by a novel mechanism of coupled adaptation of signaling channels. Experimentally, we find such 'co-adaptation' in retinal growth cones specifically for ephrin-A/EphA signaling. Co-adaptation involves trafficking of unliganded sensors between the surface membrane and recycling endosomes, and is presumably triggered by changes in the lipid composition of membrane microdomains. We propose that co-adaptative desensitization eventually relies on guidance sensor translocation into cis-signaling endosomes to outbalance repulsive trans-signaling.
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Affiliation(s)
- Felix Fiederling
- Department of Cell and Neurobiology, Karlsruhe Institute of Technology, Zoological Institute, Karlruhe, Germany
| | - Markus Weschenfelder
- Department of Cell and Neurobiology, Karlsruhe Institute of Technology, Zoological Institute, Karlruhe, Germany
| | - Martin Fritz
- Department of Cell and Neurobiology, Karlsruhe Institute of Technology, Zoological Institute, Karlruhe, Germany
| | - Anne von Philipsborn
- Department of Cell and Neurobiology, Karlsruhe Institute of Technology, Zoological Institute, Karlruhe, Germany
| | - Martin Bastmeyer
- Department of Cell and Neurobiology, Karlsruhe Institute of Technology, Zoological Institute, Karlruhe, Germany
| | - Franco Weth
- Department of Cell and Neurobiology, Karlsruhe Institute of Technology, Zoological Institute, Karlruhe, Germany
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13
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MacNearney D, Mak B, Ongo G, Kennedy TE, Juncker D. Nanocontact Printing of Proteins on Physiologically Soft Substrates to Study Cell Haptotaxis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:13525-13533. [PMID: 27993028 DOI: 10.1021/acs.langmuir.6b03246] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Surface bound guidance cues and gradients are vital for directing cellular processes during development and repair. In vivo, these cues are often presented within a soft extracellular matrix with elastic moduli E < 10 kPa, but in vitro haptotaxis experiments have been conducted primarily on hard substrates with elastic moduli in the MPa to GPa range. Here, a technique is presented for patterning haptotactic proteins with nanometer resolution on soft substrates with physiological elasticity. A new nanocontact printing process was developed that circumvented the use of plasma activation that was found to alter the mechanical properties of the substrate. A dissolvable poly(vinyl alcohol) film was first patterned by lift-off nanocontact printing, and in turn printed onto the soft substrate, followed by dissolution of the film in water. An array of 100 unique digital nanodot gradients (DNGs), consisting of millions of 200 × 200 nm2 protein nanodots, was patterned in less than 5 min with with <5% average deviation from the original gradient design. DNGs of netrin-1, a known protein guidance cue, were patterned, and the unpatterned surface was backfilled with a reference surface consisting of 75% polyethylene glycol grafted with polylysine and 25% poly-d-lysine. Haptotaxis of C2C12 myoblasts demonstrated the functionality of the DNGs patterned on soft substrates. In addition, high densities of netrin-1 were observed to induce cell spreading, while live imaging of sinusoidal control gradients highlighted cell migration and navigation by "inching". The nanopatterning technique developed here paves the way for studying haptotactic responses to diverse digital nanodot patterns on surfaces covering the full range of physiological elasticity, and is expected to be applicable to the study of both culture and primary cells, such as neutrophils and neurons.
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Affiliation(s)
- Donald MacNearney
- McGill University Genome Quebec Innovation Centre (MUGIC) , Montreal, Quebec H3A 0G1, Canada
| | - Bernard Mak
- McGill University Genome Quebec Innovation Centre (MUGIC) , Montreal, Quebec H3A 0G1, Canada
| | - Grant Ongo
- McGill University Genome Quebec Innovation Centre (MUGIC) , Montreal, Quebec H3A 0G1, Canada
| | | | - David Juncker
- McGill University Genome Quebec Innovation Centre (MUGIC) , Montreal, Quebec H3A 0G1, Canada
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14
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Naoki H, Nishiyama M, Togashi K, Igarashi Y, Hong K, Ishii S. Multi-phasic bi-directional chemotactic responses of the growth cone. Sci Rep 2016; 6:36256. [PMID: 27808115 PMCID: PMC5093620 DOI: 10.1038/srep36256] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 10/12/2016] [Indexed: 11/23/2022] Open
Abstract
The nerve growth cone is bi-directionally attracted and repelled by the same cue molecules depending on the situations, while other non-neural chemotactic cells usually show uni-directional attraction or repulsion toward their specific cue molecules. However, how the growth cone differs from other non-neural cells remains unclear. Toward this question, we developed a theory for describing chemotactic response based on a mathematical model of intracellular signaling of activator and inhibitor. Our theory was first able to clarify the conditions of attraction and repulsion, which are determined by balance between activator and inhibitor, and the conditions of uni- and bi-directional responses, which are determined by dose-response profiles of activator and inhibitor to the guidance cue. With biologically realistic sigmoidal dose-responses, our model predicted tri-phasic turning response depending on intracellular Ca2+ level, which was then experimentally confirmed by growth cone turning assays and Ca2+ imaging. Furthermore, we took a reverse-engineering analysis to identify balanced regulation between CaMKII (activator) and PP1 (inhibitor) and then the model performance was validated by reproducing turning assays with inhibitions of CaMKII and PP1. Thus, our study implies that the balance between activator and inhibitor underlies the multi-phasic bi-directional turning response of the growth cone.
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Affiliation(s)
- Honda Naoki
- Graduate School of Medicine, Kyoto University, Sakyo, Kyoto, Japan.,Imaging Platform for Spatio-temporal Information, Kyoto University, Sakyo, Kyoto, Japan
| | - Makoto Nishiyama
- Department of Biochemistry, New York University School of Medicine, New York, USA.,Kasah Technology Inc. New York, New York, USA
| | - Kazunobu Togashi
- Department of Biochemistry, New York University School of Medicine, New York, USA
| | | | - Kyonsoo Hong
- Department of Biochemistry, New York University School of Medicine, New York, USA.,Kasah Technology Inc. New York, New York, USA
| | - Shin Ishii
- Imaging Platform for Spatio-temporal Information, Kyoto University, Sakyo, Kyoto, Japan.,Graduate School of Informatics, Kyoto University, Sakyo, Kyoto, Japan
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15
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Pandiyarajan CK, Rubinstein M, Genzer J. Surface-Anchored Poly( N-isopropylacrylamide) Orthogonal Gradient Networks. Macromolecules 2016; 49:5076-5083. [PMID: 27660374 PMCID: PMC5027608 DOI: 10.1021/acs.macromol.6b01048] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a versatile synthetic route leading toward generating surface-attached polyacrylamide gels, in which the cross-link density varies continuously and gradually across the substrate in two orthogonal directions. We employ free radical polymerization to synthesize random copolymers comprising ~5% of photoactive methacrylyloxybenzophenone (MABP), ~5% of thermally active styrene sulfonyl azide (SSAz), and ~90% of N-isopropylacrylamide (NIPAAm) units. The presence of MABP and SSAz in the copolymer facilitates control over the cross-link density of the gel in an orthogonal manner using photoactivated and thermally activated cross-linking chemistries, respectively. Spectroscopic ellipsometry is employed to determine the degree of swelling of the gel in water and methanol as a function of position on the substrate. Network swelling varies continuously and gradually across the substrate and is high in regions of low gel fractions and low in regions of high gel fractions.
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Affiliation(s)
- C. K. Pandiyarajan
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Michael Rubinstein
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Jan Genzer
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
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16
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Aebersold MJ, Dermutz H, Forró C, Weydert S, Thompson-Steckel G, Vörös J, Demkó L. “Brains on a chip”: Towards engineered neural networks. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.01.025] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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17
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Green R, Abidian MR. Conducting Polymers for Neural Prosthetic and Neural Interface Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:7620-37. [PMID: 26414302 PMCID: PMC4681501 DOI: 10.1002/adma.201501810] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/11/2015] [Indexed: 05/20/2023]
Abstract
Neural-interfacing devices are an artificial mechanism for restoring or supplementing the function of the nervous system, lost as a result of injury or disease. Conducting polymers (CPs) are gaining significant attention due to their capacity to meet the performance criteria of a number of neuronal therapies including recording and stimulating neural activity, the regeneration of neural tissue and the delivery of bioactive molecules for mediating device-tissue interactions. CPs form a flexible platform technology that enables the development of tailored materials for a range of neuronal diagnostic and treatment therapies. In this review, the application of CPs for neural prostheses and other neural interfacing devices is discussed, with a specific focus on neural recording, neural stimulation, neural regeneration, and therapeutic drug delivery.
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Affiliation(s)
- Rylie Green
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Mohammad Reza Abidian
- Biomedical Engineering Department, Materials Science & Engineering Department, Chemical Engineering Department, Materials Research Institute, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 (USA)
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18
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Sloan TFW, Qasaimeh MA, Juncker D, Yam PT, Charron F. Integration of shallow gradients of Shh and Netrin-1 guides commissural axons. PLoS Biol 2015; 13:e1002119. [PMID: 25826604 PMCID: PMC4380419 DOI: 10.1371/journal.pbio.1002119] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 03/03/2015] [Indexed: 11/19/2022] Open
Abstract
During nervous system development, gradients of Sonic Hedgehog (Shh) and Netrin-1 attract growth cones of commissural axons toward the floor plate of the embryonic spinal cord. Mice defective for either Shh or Netrin-1 signaling have commissural axon guidance defects, suggesting that both Shh and Netrin-1 are required for correct axon guidance. However, how Shh and Netrin-1 collaborate to guide axons is not known. We first quantified the steepness of the Shh gradient in the spinal cord and found that it is mostly very shallow. We then developed an in vitro microfluidic guidance assay to simulate these shallow gradients. We found that axons of dissociated commissural neurons respond to steep but not shallow gradients of Shh or Netrin-1. However, when we presented axons with combined Shh and Netrin-1 gradients, they had heightened sensitivity to the guidance cues, turning in response to shallower gradients that were unable to guide axons when only one cue was present. Furthermore, these shallow gradients polarized growth cone Src-family kinase (SFK) activity only when Shh and Netrin-1 were combined, indicating that SFKs can integrate the two guidance cues. Together, our results indicate that Shh and Netrin-1 synergize to enable growth cones to sense shallow gradients in regions of the spinal cord where the steepness of a single guidance cue is insufficient to guide axons, and we identify a novel type of synergy that occurs when the steepness (and not the concentration) of a guidance cue is limiting.
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Affiliation(s)
- Tyler F. W. Sloan
- Molecular Biology of Neural Development, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
| | - Mohammad A. Qasaimeh
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
- Division of Engineering, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - David Juncker
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
- McGill University and Genome Quebec Innovation Centre, McGill University, Montreal, Quebec, Canada
| | - Patricia T. Yam
- Molecular Biology of Neural Development, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
| | - Frédéric Charron
- Molecular Biology of Neural Development, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Program in Neuroengineering, McGill University, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, Department of Biology, McGill University, Quebec, Canada
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada
- * E-mail:
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19
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Ricoult SG, Kennedy TE, Juncker D. Substrate-bound protein gradients to study haptotaxis. Front Bioeng Biotechnol 2015; 3:40. [PMID: 25870855 PMCID: PMC4378366 DOI: 10.3389/fbioe.2015.00040] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 03/13/2015] [Indexed: 12/14/2022] Open
Abstract
Cells navigate in response to inhomogeneous distributions of extracellular guidance cues. The cellular and molecular mechanisms underlying migration in response to gradients of chemical cues have been investigated for over a century. Following the introduction of micropipettes and more recently microfluidics for gradient generation, much attention and effort was devoted to study cellular chemotaxis, which is defined as guidance by gradients of chemical cues in solution. Haptotaxis, directional migration in response to gradients of substrate-bound cues, has received comparatively less attention; however, it is increasingly clear that in vivo many physiologically relevant guidance proteins - including many secreted cues - are bound to cellular surfaces or incorporated into extracellular matrix and likely function via a haptotactic mechanism. Here, we review the history of haptotaxis. We examine the importance of the reference surface, the surface in contact with the cell that is not covered by the cue, which forms a gradient opposing the gradient of the protein cue and must be considered in experimental designs and interpretation of results. We review and compare microfluidics, contact printing, light patterning, and 3D fabrication to pattern substrate-bound protein gradients in vitro. The range of methods to create substrate-bound gradients discussed herein makes possible systematic analyses of haptotactic mechanisms. Furthermore, understanding the fundamental mechanisms underlying cell motility will inform bioengineering approaches to program cell navigation and recover lost function.
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Affiliation(s)
- Sébastien G. Ricoult
- McGill Program in Neuroengineering, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Genome Quebec Innovation Centre, McGill University, Montréal, QC, Canada
| | - Timothy E. Kennedy
- McGill Program in Neuroengineering, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - David Juncker
- McGill Program in Neuroengineering, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Genome Quebec Innovation Centre, McGill University, Montréal, QC, Canada
- McGill Program in Neuroengineering, Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
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20
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Bonner JF, Steward O. Repair of spinal cord injury with neuronal relays: From fetal grafts to neural stem cells. Brain Res 2015; 1619:115-23. [PMID: 25591483 DOI: 10.1016/j.brainres.2015.01.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 12/29/2014] [Accepted: 01/05/2015] [Indexed: 02/01/2023]
Abstract
Spinal cord injury (SCI) disrupts the long axonal tracts of the spinal cord leading to devastating loss of function. Cell transplantation in the injured spinal cord has the potential to lead to recovery after SCI via a variety of mechanisms. One such strategy is the formation of neuronal relays between injured long tract axons and denervated neurons. The idea of creating a neuronal relay was first proposed over 25 years ago when fetal tissue was first successfully transplanted into the injured rodent spinal cord. Advances in labeling of grafted cells and the development of neural stem cell culturing techniques have improved the ability to create and refine such relays. Several recent studies have examined the ability to create a novel neuronal circuit between injured axons and denervated targets. This approach is an alternative to long-distance regeneration of damaged axons that may provide a meaningful degree of recovery without direct recreation of lost pathways. This brief review will examine the contribution of fetal grafting to current advances in neuronal grafting. Of particular interest will be the ability of transplanted neurons derived from fetal grafts, neural precursor cells and neural stem cells to reconnect long distance motor and sensory pathways of the injured spinal cord. This article is part of a Special Issue entitled SI: Spinal cord injury.
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Affiliation(s)
- Joseph F Bonner
- Reeve-Irvine Research Center, University of California, 1105 Gillespie Neuroscience Research Facility, Irvine, CA 92697-4265, USA.
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California, 1105 Gillespie Neuroscience Research Facility, Irvine, CA 92697-4265, USA; Departments of Anatomy & Neurobiology, Neurobiology & Behavior, and Neurosurgery, University of California at Irvine School of Medicine, Irvine, CA 92697-4265, USA
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21
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Krabbenborg SO, van Weerd J, Karperien M, Jonkheijm P, Huskens J. Locked-in biomimetic surface gradients that are tunable in size, density and functionalization. Chemphyschem 2014; 15:3460-5. [PMID: 25115904 DOI: 10.1002/cphc.201402509] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Indexed: 11/09/2022]
Abstract
Tuneable and stable surface-chemical gradients in supported lipid bilayers (SLBs) hold great promise for a range of applications in biological sensing and screening. Yet, until now, no method has been reported that provides temporal control of SLB gradients. Herein we report on the development of locked-in SLB gradients that can be tuned in space, time and density by applying a process to control lipid phase behaviour, electric field and temperature. Stable gradients of charged Texas-Red-, serine- or biotin-terminated lipids have been prepared. For example, the Texas-Red surface density was varied from 0 to 2 mol %, while the length was varied between several tens to several hundreds of microns. At room temperature the gradients are shown to be stable up to 24 h, while at 60 °C the gradients could be erased in 30 min. Covalent and non-covalent chemical modification of the gradients is demonstrated, for example, by FITC, hexahistidine-tagged proteins, and SAv/biotin. The amenability to various (bio)chemistries paves the way for novel SLB-based gradients, useful in sensing, high-throughput screening and for understanding dynamic biological processes.
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Affiliation(s)
- Sven O Krabbenborg
- Molecular NanoFabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (The Netherlands)
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22
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Li J, Duarte T, Kocabas A, Works M, McConnell SK, Hynes MA. Evidence for topographic guidance of dopaminergic axons by differential Netrin-1 expression in the striatum. Mol Cell Neurosci 2014; 61:85-96. [PMID: 24867253 DOI: 10.1016/j.mcn.2014.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 02/03/2023] Open
Abstract
There are two main subgroups of midbrain dopaminergic (DA) neurons: the more medially located ventral tegmental area (VTA) DA neurons, which have axons that innervate the ventral-lateral (VL) striatum, and the more laterally located substantia nigra (SN) DA neurons, which preferentially degenerate in Parkinson's disease (PD) and have axons that project to the dorsal-medial (DM) striatum. DA axonal projections in the striatum are not discretely localized and they arborize widely, however they do not stray from one zone to the other so that VTA axons remain in the VL zone and SN axons in the DM zone. Here we provide evidence that Netrin-1 acts in a novel fashion to topographically pattern midbrain DA axons into these two striatal zones by means of a gradient of Netrin-1 in the striatum and by differential attraction of the axons to Netrin-1. Midbrain DA neurons are attracted to the striatum in culture and this attraction is blocked by an anti-DCC (Netrin receptor) antibody. Mechanistically, outgrowth of both VTA and SN DA axons is stimulated by Netrin-1, but the two populations of DA axons respond optimally to overlapping but distinct concentrations of Netrin-1, with SN axons preferring lower concentrations and VTA axons preferring higher concentrations. In vivo this differential preference is closely mirrored by differences in Netrin-1 expression in their respective striatal target fields. In vivo in mice lacking Netrin-1, DA axons that reach the striatum fail to segregate into two terminal zones and to fully innervate the striatum. Our results reveal novel actions for Netrin-1 and provide evidence for a mechanism through which DA axons can selectively innervate one of two terminal zones in the striatum but have free reign to arborize widely within a terminal zone.
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Affiliation(s)
- Jie Li
- Department of Biology, Stanford University, Stanford, CA, United States
| | | | - Arif Kocabas
- The Rockefeller University, New York, NY, United States
| | - Melissa Works
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Susan K McConnell
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Mary A Hynes
- Department of Biology, Stanford University, Stanford, CA, United States; The Rockefeller University, New York, NY, United States.
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23
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Chelli B, Barbalinardo M, Valle F, Greco P, Bystrenova E, Bianchi M, Biscarini F. Neural cell alignment by patterning gradients of the extracellular matrix protein laminin. Interface Focus 2014; 4:20130041. [PMID: 24501672 PMCID: PMC3886309 DOI: 10.1098/rsfs.2013.0041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Anisotropic orientation and accurate positioning of neural cells is achieved by patterning stripes of the extracellular matrix protein laminin on the surface of polystyrene tissue culture dishes by micromoulding in capillaries (MIMICs). Laminin concentration decreases from the entrance of the channels in contact with the reservoir towards the end. Immunofluorescence analysis of laminin shows a decreasing gradient of concentration along the longitudinal direction of the stripes. The explanation is the superposition of diffusion and convection of the solute, the former dominating at length scales near the entrance (characteristic length around 50 μm), the latter further away (length scale in excess of 900 μm). These length scales are independent of the channel width explored from about 15 to 45 μm. Neural cells are randomly seeded and selectively adhere to the pattern, leaving the unpatterned areas depleted even upon 6 days of incubation. Cell alignment was assessed by the orientation of the long axis of the 4',6-diamidino-2-phenylindole-stained nuclei. Samples on patterned the laminin area exhibit a large orientational order parameter. As control, cells on the unpatterned laminin film exhibit no preferential orientation. This implies that the anisotropy of laminin stripes is an effective chemical stimulus for cell recruiting and alignment.
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Affiliation(s)
- Beatrice Chelli
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, Bologna 40129, Italy
- Nano4bio S.r.l, Viale G. Fanin 48, Bologna 40127, Italy
| | - Marianna Barbalinardo
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, Bologna 40129, Italy
- Nano4bio S.r.l, Viale G. Fanin 48, Bologna 40127, Italy
| | - Francesco Valle
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, Bologna 40129, Italy
| | - Pierpaolo Greco
- Scriba Nanotecnologie S.r.l, Via P. Gobetti 52/3, Bologna 40129, Italy
| | - Eva Bystrenova
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, Bologna 40129, Italy
| | - Michele Bianchi
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, Bologna 40129, Italy
| | - Fabio Biscarini
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, Bologna 40129, Italy
- Dip. Scienze della Vita, Univerità di Modena e Reggio Emilia, Via Campi 183, Modena 41125, Italy
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24
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Kannan B, Nokura K, Alvarez JC, Higgins DA, Collinson MM. Fabrication of surface charge gradients in open-tubular capillaries and their characterization by spatially resolved pulsed streaming potential measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15260-15265. [PMID: 24274139 DOI: 10.1021/la402934m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Surface charge gradients have been formed on the inside surface of 75 μm i.d. silica capillaries via controlled rate infusion using 3-aminopropyltriethoxysilane as the reactive precursor. These 400 mm length gradients have been characterized using spatially resolved streaming potential measurements, from which the zeta potential as a function of distance was determined. The gradient capillaries exhibited a gradual variation in zeta potential from top to bottom, whereas uniformly modified and as-received capillaries were relatively homogeneous along their length. For a gradient prepared with a relatively high concentration of aminosilane, the zeta potential changed over 60 mV from one end of the capillary to the other, yielding a variation in the magnitude of the apparent surface charge of ~7 fold. By changing the concentration of the aminoalkoxysilane and/or the rate of infusion, both the value of the zeta potential (and hence surface charge) and its spatial profile (i.e., rate of change with distance) could be manipulated.
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Affiliation(s)
- Balamurali Kannan
- Department of Chemistry, Virginia Commonwealth University , Richmond, Virginia 23284-2006, United States
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25
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Affiliation(s)
- Bernd Heimrich
- Institute of Anatomy, University of Freiburg, Freiburg, Germany
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26
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Woodhams PL. Laminar and region‐specific cell surface markers in the entorhinal cortex and hippocampus. Hippocampus 2013. [DOI: 10.1002/hipo.1993.4500030722] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Peter L. Woodhams
- Norman and Sadie Lee Research Centre, National Institute for Medical Research, London, U.K
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27
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Wrobel MR, Sundararaghavan HG. Directed migration in neural tissue engineering. TISSUE ENGINEERING PART B-REVIEWS 2013; 20:93-105. [PMID: 23815309 DOI: 10.1089/ten.teb.2013.0233] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Directed cell migration is particularly important in neural tissue engineering, where the goal is to direct neurons and support cells across injured nerve gaps. Investigation of the gradients present in the body during development provides an approach to guiding cells in peripheral and central nervous system tissue, but many different types of gradients and patterns can accomplish directed migration. The focus of this review is to describe current research paradigms in neural tissue gradients and review their effectiveness for directed migration. The review explores directed migration achieved through the use of chemical, adhesive, mechanical, topographical, and electrical types of gradients. Few studies investigate combined gradients, though it is known that a combination of therapies is necessary for reconnection of neuronal circuitry. To date, there has been no systematic review of gradient approaches to neural tissue engineering. By looking at effectiveness of various scaffold cue presentation and methods to combine these strategies, the potential for nerve repair is increased.
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Affiliation(s)
- Melissa R Wrobel
- Department of Biomedical Engineering, Wayne State University , Detroit, Michigan
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28
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Gieseck RL, Chan BD, Savran CA. A humidity-sensitive hydrogel-Bacillus spore composite for micropatterning of biomolecular gradients. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:085003. [PMID: 24007098 DOI: 10.1063/1.4817971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A composite material consisting of Bacillus subtilis spores suspended in a humidity sensitive hydrogel can be used to pattern biomolecules in different concentrations directly onto glass surfaces using a mechanical micromanipulator. By altering the relative humidity surrounding the composite gel during deposition, surface concentration of patterned biomolecules can be controlled and varied to create user-defined, biomolecular surface concentrations.
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Affiliation(s)
- Richard L Gieseck
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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29
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Smith Callahan LA, Ma Y, Stafford CM, Becker ML. Concentration dependent neural differentiation and neurite extension of mouse ESC on primary amine-derivatized surfaces. Biomater Sci 2013; 1:537-544. [DOI: 10.1039/c3bm00161j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Tan RZ, Ji N, Mentink RA, Korswagen HC, van Oudenaarden A. Deconvolving the roles of Wnt ligands and receptors in sensing and amplification. Mol Syst Biol 2013; 9:631. [PMID: 23295860 PMCID: PMC3564265 DOI: 10.1038/msb.2012.64] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 11/16/2012] [Indexed: 01/09/2023] Open
Abstract
Establishment of cell polarity is crucial for many biological processes including cell migration and asymmetric cell division. The establishment of cell polarity consists of two sequential processes: an external gradient is first sensed and then the resulting signal is amplified and maintained by intracellular signaling networks usually using positive feedback regulation. Generally, these two processes are intertwined and it is challenging to determine which proteins contribute to the sensing or amplification process, particularly in multicellular organisms. Here, we integrated phenomenological modeling with quantitative single-cell measurements to separate the sensing and amplification components of Wnt ligands and receptors during establishment of polarity of the Caenorhabditis elegans P cells. By systematically exploring how P-cell polarity is altered in Wnt ligand and receptor mutants, we inferred that ligands predominantly affect the sensing process, whereas receptors are needed for both sensing and amplification. This integrated approach is generally applicable to other systems and will facilitate decoupling of the different layers of signal sensing and amplification.
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Affiliation(s)
- Rui Zhen Tan
- Harvard University Graduate Biophysics Program, Harvard Medical School, Boston, MA, USA
| | - Ni Ji
- Department of Brian and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Remco A Mentink
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hendrik C Korswagen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Alexander van Oudenaarden
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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31
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Fritz M, Bastmeyer M. Microcontact printing of substrate-bound protein patterns for cell and tissue culture. Methods Mol Biol 2013; 1018:247-59. [PMID: 23681634 DOI: 10.1007/978-1-62703-444-9_23] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Patterned distributions of signalling molecules play fundamental roles during embryonic development. Several attempts have been made to reproduce these patterns in vitro. In order to study substrate-bound or membrane proteins, microcontact printing (μCP) is a suitable method for tethering molecules on various surfaces. Here, we describe three μCP variants to produce patterns down to feature sizes of about 300 nm, which are highly variable with respect to shape, protein spacing, and density. Briefly, the desired pattern is etched into a silicon master, which is then used as a master for the printing process. Each variant offers certain advantages and the method of choice depends on the desired protein and the biological question.
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Affiliation(s)
- Martin Fritz
- Department of Cell and Neurobiology, Zoological Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
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32
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Jiongjiong H, Liang Z, Zhaoxing M. The Feasibility of Delayed Repair of Facial Nerve Trauma-electrophysiological Studies and Research of Neurons and Specificity of Regeneration. INT J PHARMACOL 2012. [DOI: 10.3923/ijp.2013.58.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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33
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Kalinin YV, Murali A, Gracias DH. Chemistry with spatial control using particles and streams(). RSC Adv 2012; 2:9707-9726. [PMID: 23145348 PMCID: PMC3491979 DOI: 10.1039/c2ra20337e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Spatial control of chemical reactions, with micro- and nanometer scale resolution, has important consequences for one pot synthesis, engineering complex reactions, developmental biology, cellular biochemistry and emergent behavior. We review synthetic methods to engineer this spatial control using chemical diffusion from spherical particles, shells and polyhedra. We discuss systems that enable both isotropic and anisotropic chemical release from isolated and arrayed particles to create inhomogeneous and spatially patterned chemical fields. In addition to such finite chemical sources, we also discuss spatial control enabled with laminar flow in 2D and 3D microfluidic networks. Throughout the paper, we highlight applications of spatially controlled chemistry in chemical kinetics, reaction-diffusion systems, chemotaxis and morphogenesis.
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Affiliation(s)
- Yevgeniy V. Kalinin
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Adithya Murali
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - David H. Gracias
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
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Stettler O, Joshi RL, Wizenmann A, Reingruber J, Holcman D, Bouillot C, Castagner F, Prochiantz A, Moya KL. Engrailed homeoprotein recruits the adenosine A1 receptor to potentiate ephrin A5 function in retinal growth cones. Development 2012; 139:215-24. [PMID: 22147955 DOI: 10.1242/dev.063875] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Engrailed 1 and engrailed 2 homeoprotein transcription factors (collectively Engrailed) display graded expression in the chick optic tectum where they participate in retino-tectal patterning. In vitro, extracellular Engrailed guides retinal ganglion cell (RGC) axons and synergises with ephrin A5 to provoke the collapse of temporal growth cones. In vivo disruption of endogenous extracellular Engrailed leads to misrouting of RGC axons. Here we characterise the signalling pathway of extracellular Engrailed. Our results show that Engrailed/ephrin A5 synergy in growth cone collapse involves adenosine A1 receptor activation after Engrailed-dependent ATP synthesis, followed by ATP secretion and hydrolysis to adenosine. This is, to our knowledge, the first evidence for a role of the adenosine A1 receptor in axon guidance. Based on these results, together with higher expression of the adenosine A1 receptor in temporal than nasal growth cones, we propose a computational model that illustrates how the interaction between Engrailed, ephrin A5 and adenosine could increase the precision of the retinal projection map.
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Affiliation(s)
- Olivier Stettler
- CNRS Unité mixte de Recherche 7241/INSERM U1050, Equipe FRM, Center for Interdisciplinary Research in Biology, Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France
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35
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Fricke R, Zentis PD, Rajappa LT, Hofmann B, Banzet M, Offenhäusser A, Meffert SH. Axon guidance of rat cortical neurons by microcontact printed gradients. Biomaterials 2011; 32:2070-6. [DOI: 10.1016/j.biomaterials.2010.11.036] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 11/18/2010] [Indexed: 10/18/2022]
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36
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Simon CG, Lin-Gibson S. Combinatorial and high-throughput screening of biomaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:369-387. [PMID: 20839249 DOI: 10.1002/adma.201001763] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Indexed: 05/29/2023]
Abstract
Combinatorial and high-throughput methods have been increasingly used to accelerate research and development of new biomaterials. These methods involve creating miniaturized libraries that contain many specimens in one sample in the form of gradients or arrays, followed by automated data collection and analysis. This article reviews recent advances in utilizing combinatorial and high-throughput methods to better understand cell-material interactions, particularly highlighting our efforts at the NIST Polymers Division. Specifically, fabrication techniques to generate controlled surfaces (2D) and 3D cell environments (tissue engineering scaffolds) as well as methods to characterize and analyze material properties and cell-material interactions are described. In conclusion, additional opportunities for combinatorial methods for biomaterials research are noted, including streamlined sample fabrication and characterization, appropriate and automated bioassays, and data analysis.
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Affiliation(s)
- Carl G Simon
- Polymers Division, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, MD 29899, USA
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37
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Poly(L-lysine)-grafted-poly(ethylene glycol)-based surface-chemical gradients. Preparation, characterization, and first applications. Biointerphases 2010; 1:156-65. [PMID: 20408629 DOI: 10.1116/1.2431704] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A simple dipping process has been used to prepare PEGylated surface gradients from the polycationic polymer poly(L-lysine), grafted with poly(ethylene glycol) (PLL-g-PEG), on metal oxide substrates, such as TiO(2) and Nb(2)O(5). PLL-g-PEG coverage gradients were prepared during an initial, controlled immersion and characterized with variable angle spectroscopic ellipsometry and x-ray photoelectron spectroscopy. Gradients with a linear change in thickness and coverage were generated by the use of an immersion program based on an exponential function. These single-component gradients were used to study the adsorption of proteins of different sizes and shapes, namely, albumin, immunoglobulin G, and fibrinogen. The authors have shown that the density and size of defects in the PLL-g-PEG adlayer determine the amount of protein that is adsorbed at a certain adlayer thickness. In a second step, single-component gradients of functionalized PLL-g-PEG were backfilled with nonfunctionalized PLL-g-PEG to generate two-component gradients containing functional groups, such as biotin, in a protein-resistant background. Such gradients were combined with a patterning technique to generate individually addressable spots on a gradient surface. The surfaces generated in this way show promise as a useful and versatile biochemical screening tool and could readily be incorporated into a method for studying the behavior of cells on functionalized surfaces.
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Abstract
Extracellular gradients of secreted guidance factors are known to guide axon pathfinding and neuronal migration. These factors are likely to bind to cell surfaces or extracellular matrix, but whether and how they may act in bound gradients remains mostly unclear. In this study, we have developed a new technique for rapid production of stable microscopic gradients of substrate-bound proteins by covalent bonding of the proteins with an epoxy-coated glass substrate while they are diffusing in an agarose gel. Using this method, we found that bound gradients of netrin-1 and brain-derived neurotrophic factor (BDNF) can polarize the initiation and turning of axons in cultured hippocampal neurons. Furthermore, bound BDNF gradient caused attractive and repulsive polarizing response on gradients of low- and high-average density of BDNF, respectively. This novel bidirectional response to BDNF depended on the basal level of cAMP in the neuron. Finally, our data showed that the neuron's attractive response to bound BDNF gradient depended on the absolute difference rather than the relative difference in the BDNF density across the neuron, with a minimal effective difference of 1-2 BDNF molecule/mum(2) on the substrate surface. Thus, substrate-bound guidance factors are highly effective in polarizing axon initiation and growth, and the diffusive printing technique is useful for studying neuronal responses induced by bound protein gradients.
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40
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Burton EA, Simon KA, Hou S, Ren D, Luk YY. Molecular gradients of bioinertness reveal a mechanistic difference between mammalian cell adhesion and bacterial biofilm formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:1547-1553. [PMID: 19133791 DOI: 10.1021/la803261b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemical gradients play an important role in guiding the activities of both eukaryotic and prokaryotic cells. Here, we used molecularly well-defined chemical gradients formed by self-assembled monolayers (SAMs) on gold films to reveal that mammalian cell adhesion and bacterial biofilm formation respond differently to a gradient of surface chemistry that resists cell attachment. Gradient self-assembled monolayers (SAMs) consisting of two mixed alkanethiols were fabricated by differential exposure of the gold film to one alkanethiol, followed by soaking in another alkanethiol solution. A gradient in bioinertness that resisted cell attachment was created on SAMs from a gradient in the surface density of HS(CH2)11(OCH2CH2)3OH, backfilled with either HS(CH2)11OH or HS(CH2)11CH3. Measurements of the amounts of mammalian cells and bacterial biofilms on these gradient surfaces reveal that, for mammalian cells, a critical density of adhesion ligands from absorbed proteins on surfaces exists for supporting maximum adhesion and proliferation, whereas for the bacterium Escherichia coli , the amount of biofilm formed on surfaces increased linearly with the surface density of adhesive groups (methyl or hydroxyl groups) in different media. These results are consistent with mammalian cell adhesion requiring an anchorage via specific molecular recognitions and suggest that biofilms can form by immobilization of bacteria via nonspecific interaction between bacteria and surfaces.
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Affiliation(s)
- Erik A Burton
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA
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41
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Kaplan S, Odaci E, Unal B, Sahin B, Fornaro M. Chapter 2 Development of the Peripheral Nerve. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:9-26. [DOI: 10.1016/s0074-7742(09)87002-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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42
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Bélisle JM, Correia JP, Wiseman PW, Kennedy TE, Costantino S. Patterning protein concentration using laser-assisted adsorption by photobleaching, LAPAP. LAB ON A CHIP 2008; 8:2164-7. [PMID: 19023482 DOI: 10.1039/b813897d] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The study of cellular responses to changes in the spatial distribution of molecules in development, immunology and cancer, requires reliable methods to reproduce in vitro the precise distributions of proteins found in vivo. Here we present a straightforward method for generating substrate-bound protein patterns which has the simplicity required to be implemented in typical life science laboratories. The method exploits photobleaching of fluorescently tagged molecules to generate patterns and concentration gradients of protein with sub-micron spatial resolution. We provide an extensive characterization of the technique and demonstrate, as proof of principle, axon guidance by gradients of substrate-bound laminin peptide generated in vitro using LAPAP.
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43
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Nishiura Y, Hara Y, Yoshii Y, Ochiai N. Gradual stretching of the proximal nerve stump induces the growth of regenerating sprouts in rats. J Orthop Res 2008; 26:1012-7. [PMID: 18327803 DOI: 10.1002/jor.20587] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the effect of direct gradual stretching on the proximal nerve stump morphologically. A 10-mm-long nerve segment was resected from the sciatic nerve of a rat. The end of the proximal nerve stump was fixed to a small ring and the marking suture was placed at a point 1 mm proximal to the ring. Then, the nerve stump was lengthened at a rate of 1 mm/day via a stretching of the ring using an original external device. After a stretching of 20 days, the distance from the ring to the marking suture became 12 mm. Whereas large mature myelinated axons were observed in the proximal part of the marking, only small axons with thin myelin sheath were observed in the distal part, and the mean axonal diameter showed a significant difference between the two parts. Moreover, the mean internodal length was 172.4 +/- 13.4 microm in the distal part of the marking and 1019.0 +/- 56.2 microm in the proximal part. The internodal length also showed a significant difference between the two parts. Thus, the axonal diameter and internodal length were consistent with the characteristics of regenerating axons in the distal part. Furthermore, ultrastructural analysis also showed the histological characteristics of axonal regeneration. Thus, a transected proximal nerve stump may be lengthened by axonal regeneration during gradual stretching, and the stimulus of mechanical stretching may induce the growth of regenerating axons.
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44
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Multi-Molecular Gradients of Permissive and Inhibitory Cues Direct Neurite Outgrowth. Ann Biomed Eng 2008; 36:889-904. [PMID: 18392680 DOI: 10.1007/s10439-008-9486-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Accepted: 10/09/2007] [Indexed: 10/22/2022]
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45
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Costantino S, McQuinn CG, Kennedy TE, Wiseman PW. Fabrication of protein gradients for cell culture using a miniature squeegee. ACTA ACUST UNITED AC 2008; 70:1192-5. [PMID: 17597222 DOI: 10.1016/j.jbbm.2007.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 05/25/2007] [Accepted: 05/29/2007] [Indexed: 11/15/2022]
Abstract
We present a straightforward method to create spatial gradients of substrate bound protein for live cell studies using only mechanical parts. Protein concentration gradients on a micron scale can be fabricated in several minutes for a relatively low cost using a method that is generally applicable to any protein and substrate combination. We describe the details of the device construction, and provide examples of mammalian cells grown on substrates patterned with protein concentration gradients using this technique.
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Affiliation(s)
- Santiago Costantino
- McGill Program in NeuroEngineering, Department of Physics, McGill University, Montréal, Québec, Canada.
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46
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Luzinov I, Minko S, Tsukruk VV. Responsive brush layers: from tailored gradients to reversibly assembled nanoparticles. SOFT MATTER 2008; 4:714-725. [PMID: 32907173 DOI: 10.1039/b718999k] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We present a condensed overview of the recent developments of novel responsive thin polymer films from end-tethered chains (polymer brushes), which are different from conventional, uniform, and planar brush layers. For this discussion, we selected two types of recently introduced surface layers: binary brush layers with variable chemical composition forming a controllable gradient of composition and properties in a selected direction and brush layers either grafted directly to inorganic nanoparticles to form hybrid core-shell structures or combined with inorganic nanoparticles embedded into this layer. Unlike traditional brush layers, such a design brings a novel set of responsive surface properties allowing for capillary-driven microfluidic motion, combinatorial-like multiplexing response, reversible aggregation and dis-assembly of nanoparticles, fabrication of ultrahydrophobic coatings, and switchable mass transport across interfaces.
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Affiliation(s)
- Igor Luzinov
- School of Materials Science and Engineering and Center for Optical Materials Science and Engineering Technologies, Clemson University, Clemson, SC 29634, USA.
| | - Sergiy Minko
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY 13699, USA.
| | - Vladimir V Tsukruk
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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47
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Genzer J, Bhat RR. Surface-bound soft matter gradients. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:2294-2317. [PMID: 18220435 DOI: 10.1021/la7033164] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This feature article describes the progress realized over the past half century in the field of surface-bound gradient structures created on or from soft materials (oligomers and/or polymers), or those enabling the study of the behavior of soft materials. By highlighting our work in the field and accounting for the contribution of other groups, we emphasize the exceptional versatility of gradient assemblies in facilitating fast screening of physicochemical phenomena, acting as "recording media" for monitoring a process, and playing a key role in the design and fabrication of surface-bound molecular and macromolecular motors capable of directing a transport phenomenon.
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Affiliation(s)
- Jan Genzer
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA.
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48
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Morgenthaler S, Zink C, Spencer ND. Surface-chemical and -morphological gradients. SOFT MATTER 2008; 4:419-434. [PMID: 32907200 DOI: 10.1039/b715466f] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface gradients of chemistry or morphology represent powerful tools for the high-throughput investigation of interfacial phenomena in the areas of physics, chemistry, materials science and biology. A wide variety of methods for the fabrication of such gradients has been developed in recent years, relying on principles ranging from diffusion to time-dependent irradiation in order to achieve a gradual change of a particular parameter across a surface. In this review we have endeavoured to cover the principal fabrication approaches for surface-chemical and surface-morphological gradients that have been described in the literature, and to provide examples of their applications in a variety of different fields.
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Affiliation(s)
- Sara Morgenthaler
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland.
| | - Christian Zink
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland.
| | - Nicholas D Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland.
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49
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Kidambi S, Lee I. Primary Neuron/Astrocyte Co-Culture on Polyelectrolyte Multilayer Films: A Template for Studying Astrocyte-Mediated Oxidative Stress in Neurons. ADVANCED FUNCTIONAL MATERIALS 2008; 18:294-301. [PMID: 25400537 PMCID: PMC4229016 DOI: 10.1002/adfm.200601237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We engineered patterned co-cultures of primary neurons and astrocytes on polyelectrolyte multilayer (PEM) films without the aid of adhesive proteins/ligands to study the oxidative stress mediated by astrocytes on neuronal cells. A number of studies have explored engineering co-culture of neurons and astrocytes predominantly using cell lines rather than primary cells owing to the difficulties involved in attaching primary cells onto synthetic surfaces. To our knowledge this is the first demonstration of patterned co-culture of primary neurons and astrocytes for studying neuronal metabolism. In our study, we used synthetic polymers, namely poly(diallyldimethylammoniumchloride) (PDAC) and sulfonated poly(styrene) (SPS) as the polycation and polyanion, respectively, to build the multilayers. Primary neurons attached and spread preferentially on SPS surfaces, while primary astrocytes attached to both SPS and PDAC surfaces. SPS patterns were formed on PEM surfaces, either by microcontact printing SPS onto PDAC surfaces or vice-versa, to obtain patterns of primary neurons and patterned co-cultures of primary neurons and astrocytes. We further used the patterned co-culture system to study the neuronal response to elevated levels of free fatty acids as compared to the response in separated monoculture by measuring the level of reactive oxygen species (ROS; a widely accepted marker of oxidative stress). The elevation in the ROS levels was observed to occur earlier in the patterned co-culture system than in the separated monoculture system. The results suggest that this technique may provide a useful tool for engineering neuronal co-culture systems, that may more accurately capture neuronal function and metabolism, and thus could be used to obtain valuable insights into neuronal cell function and perhaps even the pathogenesis of neurodegenerative diseases.
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50
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Kemp SWP, Walsh SK, Zochodne DW, Midha R. A novel method for establishing daily in vivo concentration gradients of soluble nerve growth factor (NGF). J Neurosci Methods 2007; 165:83-8. [PMID: 17624441 DOI: 10.1016/j.jneumeth.2007.05.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 05/24/2007] [Accepted: 05/25/2007] [Indexed: 11/24/2022]
Abstract
Despite the capacity for spontaneous axonal regeneration, recovery following injuries to the peripheral nervous system (PNS) following transection are often incomplete and limited to short distances. Nerve growth factor (NGF) has been previously shown to support neuron survival, and direct growth of both developing and regenerating nerve fibers along a concentration gradient, based largely on in vitro studies. Here, we present a novel in vivo model of administering daily concentration gradients of NGF by directly manipulating the placement of the catheter-nerve conduit junction. Our results show that a dose of 800 pg NGF can be reliably used to establish a chemotactic concentration gradient over both a transient time period, and chronically through repeated daily administrations of the drug. Results from these studies may lead to a better mechanistic understanding of how concentration gradients of soluble NGF influence in vivo peripheral nerve regeneration.
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Affiliation(s)
- Stephen W P Kemp
- Department of Clinical Neuroscience, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1.
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