1
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Dixon AR, Horst EN, Garcia JJ, Ndjouyep-Yamaga PR, Mehta G. Morphometric and computational assessments to evaluate neuron survival and maturation within compartmentalized microfluidic devices: The influence of design variation on diffusion-driven nutrient transport. Neurosci Lett 2019; 703:58-67. [PMID: 30885631 DOI: 10.1016/j.neulet.2019.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/11/2019] [Accepted: 03/14/2019] [Indexed: 11/26/2022]
Abstract
Burgeoning use of segregated microfluidic platforms that parse somas and neurites into discrete compartments is fueling unique examinations of neuronal structure and physiology in a manner impossible to achieve with non-compartmentalized systems. However, even though this line of axon-soma polarizing microfluidic devices stems from the same general design of a Campenot chamber set-up, slight deviations in device geometry appear to induce vastly different nutrient transport profiles that influence neuron survival and maturation. Here we examine the uptake of nerve growth factor (NGF) by a pheochromocytoma PC12 cell line cultured using two Campenot-like device designs, a "Standard" layout, representative of a commercial device, and a custom "Notch" layout, predicted to encourage more efficient nutrient transfer that gives rise to sustained neuron viability and extensive neurite elaboration. Exploiting in vitro culture schemes coupled with computational analyses, we identify the influence of device design geometry on the interplay between neuronal survival and maturation, gauged from morphometric assessments and the spatiotemporal distribution of NGF. Computer simulations of NGF transport within the devices revealed that the microfluidic neuron culture system is highly sensitive to change, where nutrient transport is intricately linked to device geometry and cell plating density, and premature depletion of nutrients is observed if specific design criteria are not met. This study underscores the importance of validating specific device geometries for a particular neuro-based assessment, while showcasing computational modeling as a powerful tool to achieve this goal.
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Affiliation(s)
- Angela R Dixon
- Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Eric N Horst
- Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA; Material Science and Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jeniffer J Garcia
- Neuroscience, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Patricia R Ndjouyep-Yamaga
- Neuroscience, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Geeta Mehta
- Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA; Material Science and Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA; Macromolecular Science and Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
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2
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A microfabricated nerve-on-a-chip platform for rapid assessment of neural conduction in explanted peripheral nerve fibers. Nat Commun 2018; 9:4403. [PMID: 30353009 PMCID: PMC6199302 DOI: 10.1038/s41467-018-06895-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 09/24/2018] [Indexed: 02/07/2023] Open
Abstract
Peripheral nerves are anisotropic and heterogeneous neural tissues. Their complex physiology restricts realistic in vitro models, and high resolution and selective probing of axonal activity. Here, we present a nerve-on-a-chip platform that enables rapid extracellular recording and axonal tracking of action potentials collected from tens of myelinated fibers. The platform consists of microfabricated stimulation and recording microchannel electrode arrays. First, we identify conduction velocities of action potentials traveling through the microchannel and propose a robust data-sorting algorithm using velocity selective recording. We optimize channel geometry and electrode spacing to enhance the algorithm reliability. Second, we demonstrate selective heat-induced neuro-inhibition of peripheral nerve activity upon local illumination of a conjugated polymer (P3HT) blended with a fullerene derivative (PCBM) coated on the floor of the microchannel. We demonstrate the nerve-on-a-chip platform is a versatile tool to optimize the design of implantable peripheral nerve interfaces and test selective neuromodulation techniques ex vivo. Peripheral nerves have a complex physiology and it is therefore difficult to measure axonal activity in vitro. Here the authors make a nerve-on-a-chip platform to align peripheral nerves and permit measurement of conduction amplitude and velocity along several axons in a single experiment.
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3
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Magrì A, La Mendola D. Copper Binding Features of Tropomyosin-Receptor-Kinase-A Fragment: Clue for Neurotrophic Factors and Metals Link. Int J Mol Sci 2018; 19:ijms19082374. [PMID: 30103559 PMCID: PMC6121459 DOI: 10.3390/ijms19082374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/01/2018] [Accepted: 08/07/2018] [Indexed: 12/31/2022] Open
Abstract
The nerve growth factor (NGF) is a neurotrophin essential for the development and maintenance of neurons, whose activity is influenced by copper ions. The NGF protein exerts its action by binding to its specific receptor, TrkA. In this study, a specific domain of the TrkA receptor, region 58⁻64, was synthesized and its copper(II) complexes characterized by means of potentiometric and spectroscopic studies. The two vicinal histidine residues provide excellent metal anchoring sites and, at physiological pH, a complex with the involvement of the peptide backbone amide nitrogen is the predominant species. The TrkA peptide is competitive for metal binding with analogous peptides due to the N-terminal domain of NGF. These data provide cues for future exploration of the effect of metal ions on the activity of the NGF and its specific cellular receptor.
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Affiliation(s)
- Antonio Magrì
- Institute of Biostructures and Bioimages, National Council of Research (CNR), Via Paolo Gaifami 18, 95126 Catania, Italy.
- Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici (CIRCMSB), via Celso Ulpiani, 27, 70125 Bari, Italy.
| | - Diego La Mendola
- Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici (CIRCMSB), via Celso Ulpiani, 27, 70125 Bari, Italy.
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano 6, 56126 Pisa, Italy.
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4
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Asghari Adib E, Smithson LJ, Collins CA. An axonal stress response pathway: degenerative and regenerative signaling by DLK. Curr Opin Neurobiol 2018; 53:110-119. [PMID: 30053694 DOI: 10.1016/j.conb.2018.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/02/2018] [Indexed: 02/08/2023]
Abstract
Signaling through the dual leucine zipper-bearing kinase (DLK) is required for injured neurons to initiate new axonal growth; however, activation of this kinase also leads to neuronal degeneration and death in multiple models of injury and neurodegenerative diseases. This has spurred current consideration of DLK as a candidate therapeutic target, and raises a vital question: in what context is DLK a friend or foe to neurons? Here, we review our current understanding of DLK's function and mechanisms in regulating both regenerative and degenerative responses to axonal damage and stress in the nervous system.
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Affiliation(s)
- Elham Asghari Adib
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Laura J Smithson
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Catherine A Collins
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA.
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5
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Use of mathematics to guide target selection in systems pharmacology; application to receptor tyrosine kinase (RTK) pathways. Eur J Pharm Sci 2017; 109S:S140-S148. [PMID: 28549678 DOI: 10.1016/j.ejps.2017.05.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 05/22/2017] [Indexed: 11/24/2022]
Abstract
A key element of the drug discovery process is target selection. Although the topic is subject to much discussion and experimental effort, there are no defined quantitative rules around optimal selection. Often 'rules of thumb', that have not been subject to rigorous exploration, are used. In this paper we explore the 'rule of thumb' notion that the molecule that initiates a pathway signal is the optimal target. Given the multi-factorial and complex nature of this question, we have simplified an example pathway to its logical minimum of two steps and used a mathematical model of this to explore the different options in the context of typical small and large molecule drugs. In this paper, we report the conclusions of our analysis and describe the analysis tool and methods used. These provide a platform to enable a more extensive enquiry into this important topic.
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6
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Feinberg K, Kolaj A, Wu C, Grinshtein N, Krieger JR, Moran MF, Rubin LL, Miller FD, Kaplan DR. A neuroprotective agent that inactivates prodegenerative TrkA and preserves mitochondria. J Cell Biol 2017; 216:3655-3675. [PMID: 28877995 PMCID: PMC5674898 DOI: 10.1083/jcb.201705085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/26/2017] [Accepted: 08/01/2017] [Indexed: 12/15/2022] Open
Abstract
The pan-kinase inhibitor foretinib is identified as a potent suppressor of sympathetic, sensory, and motor neuron axon degeneration, acting in part by inhibiting the activity of the unliganded TrkA/nerve growth factor receptor and by preserving mitochondria in die-back and Wallerian degeneration models. Axon degeneration is an early event and pathological in neurodegenerative conditions and nerve injuries. To discover agents that suppress neuronal death and axonal degeneration, we performed drug screens on primary rodent neurons and identified the pan-kinase inhibitor foretinib, which potently rescued sympathetic, sensory, and motor wt and SOD1 mutant neurons from trophic factor withdrawal-induced degeneration. By using primary sympathetic neurons grown in mass cultures and Campenot chambers, we show that foretinib protected neurons by suppressing both known degenerative pathways and a new pathway involving unliganded TrkA and transcriptional regulation of the proapoptotic BH3 family members BimEL, Harakiri,and Puma, culminating in preservation of mitochondria in the degenerative setting. Foretinib delayed chemotherapy-induced and Wallerian axonal degeneration in culture by preventing axotomy-induced local energy deficit and preserving mitochondria, and peripheral Wallerian degeneration in vivo. These findings identify a new axon degeneration pathway and a potentially clinically useful therapeutic drug.
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Affiliation(s)
- Konstantin Feinberg
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - Adelaida Kolaj
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Chen Wu
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Harvard University, Cambridge, MA
| | - Natalie Grinshtein
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - Jonathan R Krieger
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada
| | - Michael F Moran
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Lee L Rubin
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Harvard University, Cambridge, MA
| | - Freda D Miller
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - David R Kaplan
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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7
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Lewandowska MK, Radivojević M, Jäckel D, Müller J, Hierlemann AR. Cortical Axons, Isolated in Channels, Display Activity-Dependent Signal Modulation as a Result of Targeted Stimulation. Front Neurosci 2016; 10:83. [PMID: 27013945 PMCID: PMC4779934 DOI: 10.3389/fnins.2016.00083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/19/2016] [Indexed: 12/01/2022] Open
Abstract
Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10-20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells' signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations.
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Affiliation(s)
- Marta K Lewandowska
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zürich Basel, Switzerland
| | - Miloš Radivojević
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zürich Basel, Switzerland
| | - David Jäckel
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zürich Basel, Switzerland
| | - Jan Müller
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zürich Basel, Switzerland
| | - Andreas R Hierlemann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering, ETH Zürich Basel, Switzerland
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8
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De Nadai T, Marchetti L, Di Rienzo C, Calvello M, Signore G, Di Matteo P, Gobbo F, Turturro S, Meucci S, Viegi A, Beltram F, Luin S, Cattaneo A. Precursor and mature NGF live tracking: one versus many at a time in the axons. Sci Rep 2016; 6:20272. [PMID: 26829890 PMCID: PMC4735336 DOI: 10.1038/srep20272] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/14/2015] [Indexed: 12/11/2022] Open
Abstract
The classical view of nerve growth factor (NGF) action in the nervous system is linked to its retrograde axonal transport. However, almost nothing is known on the trafficking properties of its unprocessed precursor proNGF, characterized by different and generally opposite biological functions with respect to its mature counterpart. Here we developed a strategy to fluorolabel both purified precursor and mature neurotrophins (NTs) with a controlled stoichiometry and insertion site. Using a single particle tracking approach, we characterized the axonal transport of proNGF versus mature NGF in living dorsal root ganglion neurons grown in compartmentalized microfluidic devices. We demonstrate that proNGF is retrogradely transported as NGF, but with a lower flux and a different distribution of numbers of neurotrophins per vesicle. Moreover, exploiting a dual-color labelling technique, we analysed the transport of both NT forms when simultaneously administered to the axon tips.
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Affiliation(s)
- Teresa De Nadai
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | - Laura Marchetti
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy.,NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy
| | - Carmine Di Rienzo
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | | | - Giovanni Signore
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | - Pierluigi Di Matteo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | - Francesco Gobbo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | | | - Sandro Meucci
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | - Alessandro Viegi
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | - Fabio Beltram
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | - Stefano Luin
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy
| | - Antonino Cattaneo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
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9
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Shi W, Wang F, Gao M, Yang Y, Du Z, Wang C, Yao Y, He K, Chen X, Hao A. ZDHHC17 promotes axon outgrowth by regulating TrkA-tubulin complex formation. Mol Cell Neurosci 2015; 68:194-202. [PMID: 26232532 DOI: 10.1016/j.mcn.2015.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 07/07/2015] [Accepted: 07/23/2015] [Indexed: 12/14/2022] Open
Abstract
Correct axonal growth during nervous system development is critical for synaptic transduction and nervous system function. Proper axon outgrowth relies on a suitable growing environment and the expression of a series of endogenous neuronal factors. However, the mechanisms of these neuronal proteins involved in neuronal development remain unknown. ZDHHC17 is a member of the DHHC (Asp-His-His-Cys)-containing family, a family of highly homologous proteins. Here, we show that loss of function of ZDHHC17 in zebrafish leads to motor dysfunction in 3-day post-fertilization (dpf) larvae. We performed immunolabeling analysis to reveal that mobility dysfunction was due to a significant defect in the axonal outgrowth of spinal motor neurons (SMNs) without affecting neuron generation. In addition, we found a similar phenotype in zdhhc17 siRNA-treated neural stem cells (NSCs) and PC12 cells. Inhibition of zdhhc17 limited neurite outgrowth and branching in both NSCs and PC12. Furthermore, we discovered that the level of phosphorylation of extracellular-regulated kinase (ERK) 1/2, a major downstream effector of tyrosine kinase (TrkA), was largely upregulated in ZDHHC17 overexpressing PC12 cells by a mechanism independent on its palmitoyltransferase (PAT) activity. Specifically, ZDHHC17 is necessary for proper TrkA-tubulin module formation in PC12 cells. These results strongly indicate that ZDHHC17 is essential for correct axon outgrowth in vivo and in vitro. Our findings identify ZDHHC17 as an important upstream factor of ERK1/2 to regulate the interaction between TrkA and tubulin during neuronal development.
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Affiliation(s)
- Wei Shi
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Fen Wang
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Ming Gao
- Reproductive Medical Center of Shandong University, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Yang Yang
- Infertility Center, Qilu Hospital, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Zhaoxia Du
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Chen Wang
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Yao Yao
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Kun He
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China
| | - Xueran Chen
- Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China.
| | - Aijun Hao
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, No. 44, Wenhua Xi Road, Jinan, Shandong 250012, PR China.
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10
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D’Angelo L, Castaldo L, Cellerino A, de Girolamo P, Lucini C. Nerve growth factor in the adult brain of a teleostean model for aging research: Nothobranchius furzeri. Ann Anat 2014; 196:183-91. [DOI: 10.1016/j.aanat.2014.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/24/2014] [Accepted: 02/16/2014] [Indexed: 12/31/2022]
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11
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Benson N, Matsuura T, Smirnov S, Demin O, Jones HM, Dua P, van der Graaf PH. Systems pharmacology of the nerve growth factor pathway: use of a systems biology model for the identification of key drug targets using sensitivity analysis and the integration of physiology and pharmacology. Interface Focus 2014; 3:20120071. [PMID: 24427523 DOI: 10.1098/rsfs.2012.0071] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The nerve growth factor (NGF) pathway is of great interest as a potential source of drug targets, for example in the management of certain types of pain. However, selecting targets from this pathway either by intuition or by non-contextual measures is likely to be challenging. An alternative approach is to construct a mathematical model of the system and via sensitivity analysis rank order the targets in the known pathway, with respect to an endpoint such as the diphosphorylated extracellular signal-regulated kinase concentration in the nucleus. Using the published literature, a model was created and, via sensitivity analysis, it was concluded that, after NGF itself, tropomyosin receptor kinase A (TrkA) was one of the most sensitive druggable targets. This initial model was subsequently used to develop a further model incorporating physiological and pharmacological parameters. This allowed the exploration of the characteristics required for a successful hypothetical TrkA inhibitor. Using these systems models, we were able to identify candidates for the optimal drug targets in the known pathway. These conclusions were consistent with clinical and human genetic data. We also found that incorporating appropriate physiological context was essential to drawing accurate conclusions about important parameters such as the drug dose required to give pathway inhibition. Furthermore, the importance of the concentration of key reactants such as TrkA kinase means that appropriate contextual data are required before clear conclusions can be drawn. Such models could be of great utility in selecting optimal targets and in the clinical evaluation of novel drugs.
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Affiliation(s)
- Neil Benson
- Xenologiq Ltd, Unit 7 , Denne Hill Business Park, Canterbury CT4 6HD , UK ; Department of Pharmacokinetics, Dynamics and Metabolism , Pfizer Worldwide R&D , Boston, MA , USA
| | - Tomomi Matsuura
- Department of Pharmacokinetics, Dynamics and Metabolism , Pfizer Worldwide R&D , Boston, MA , USA ; Astellas , 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585 , Japan
| | - Sergey Smirnov
- Institute for Systems Biology SPb, Leninskie Gory 1/75G, Moscow 119992 , Russia
| | - Oleg Demin
- Institute for Systems Biology SPb, Leninskie Gory 1/75G, Moscow 119992 , Russia
| | - Hannah M Jones
- Department of Pharmacokinetics, Dynamics and Metabolism , Pfizer Worldwide R&D , Boston, MA , USA
| | - Pinky Dua
- Pharmatherapeutics Clinical Pharmacology, Pfizer Neusentis , The Portway Building, Granta Park, Cambridge CB21 6GS , UK ; Neusentis, Pfizer Global Clinical Pharmacology , The Portway Building, Granta Park, Cambridge CB21 6GS , UK
| | - Piet H van der Graaf
- Department of Pharmacokinetics, Dynamics and Metabolism , Pfizer Worldwide R&D , Boston, MA , USA ; Neusentis, Pfizer Global Clinical Pharmacology , The Portway Building, Granta Park, Cambridge CB21 6GS , UK ; Leiden Academic Centre for Drug Research (LACDR) , Leiden RA 2300 , The Netherlands
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12
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Mok SA, Lund K, Lapointe P, Campenot RB. A HaloTag® method for assessing the retrograde axonal transport of the p75 neurotrophin receptor and other proteins in compartmented cultures of rat sympathetic neurons. J Neurosci Methods 2013; 214:91-104. [PMID: 23348044 DOI: 10.1016/j.jneumeth.2013.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 10/19/2012] [Accepted: 01/08/2013] [Indexed: 11/30/2022]
Abstract
We have adapted HaloTag® (HT) technology for use in compartmented cultures of rat sympathetic neurons in order to provide a technique that can be broadly applied to studies of the retrograde transport of molecules that play roles in neurotrophin signaling. Transfected neurons expressing HT protein alone, HT protein fused to the p75 neurotrophin receptor (p75NTR) or HT protein fused to tubulin α-1B were maintained in compartmented cultures in which cell bodies and proximal axons of rat sympathetic neurons reside in proximal compartments and their distal axons extend into distal compartments. HT ligand containing a fluorescent tetramethylrhodamine (TMR) label was applied either in the distal compartments or the proximal compartments, and the transport of labeled proteins was assayed by gel fluorescence imaging and TMR immunoblot. HT protein expressed alone displayed little or no retrograde transport. HT protein fused to either the intracellular C-terminus or the extracellular N-terminus of p75NTR was retrogradely transported. The retrograde transport of p75NTR was augmented when the distal axons were provided with nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) or antibodies to BDNF. The anterograde transport of HT protein fused to the N-terminus of tubulin α-1B was also demonstrated. We conclude that retrograde transport of HT fusion proteins provides a powerful and novel approach in studies of axonal transport.
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Affiliation(s)
- Sue-Ann Mok
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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13
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Atopic keratinocytes induce increased neurite outgrowth in a coculture model of porcine dorsal root ganglia neurons and human skin cells. J Invest Dermatol 2012; 132:1892-900. [PMID: 22418869 DOI: 10.1038/jid.2012.44] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Skin of patients suffering from atopic eczema displays a higher epidermal nerve fiber density, associated with neurogenic inflammation and pruritus. Using an in vitro coculture system, allowing a spatially compartmented culture of somata from porcine dorsal root ganglion neurons and human primary skin cells, we investigated the influence of dermal fibroblasts and keratinocytes on neurite outgrowth. In comparison with dermal fibroblasts, keratinocytes induced more branched and less calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers. By adding neutralizing antibodies, we showed that nerve growth factor (NGF) and glial cell-line-derived neurotrophic factor (GDNF) are pivotal neurotrophic factors of skin cell-induced neurite outgrowth. Keratinocytes and dermal fibroblasts secreted different ratios of neurotrophic factors, influencing morphology and CGRP immunoreactivity of neurites. To investigate changes of the peripheral nervous system in the pathogenesis of atopic eczema in vitro, we analyzed neurite outgrowth mediated by atopic skin cells. Atopic keratinocytes produced elevated levels of NGF and mediated an increased outgrowth of CGRP-positive sensory fibers. Our results demonstrate the impact of dermal fibroblasts and keratinocytes on skin innervation and emphasize the role of keratinocytes as key players of hyperinnervation in atopic eczema.
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Abstract
Neurotrophins are a family of target-derived growth factors that support survival, development, and maintenance of innervating neurons. Owing to the unique architecture of neurons, neurotrophins that act locally on the axonal terminals must convey their signals across the entire axon for subsequent regulation of gene transcription in the cell nucleus. This long-distance retrograde signaling, a motor-driven process that can take hours or days, has been a subject of intense interest. In the last decade, live-cell imaging with high sensitivity has significantly increased our capability to track the transport of neurotrophins, their receptors, and subsequent signals in real time. This review summarizes recent research progress in understanding neurotrophin-receptor interactions at the axonal terminal and their transport dynamics along the axon. We emphasize high-resolution studies at the single-molecule level and also discuss recent technical advances in the field.
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D'Angelo L, de Girolamo P, Cellerino A, Tozzini ET, Castaldo L, Lucini C. Neurotrophin Trk receptors in the brain of a teleost fish, Nothobranchius furzeri. Microsc Res Tech 2012; 75:81-8. [DOI: 10.1002/jemt.21028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 04/06/2011] [Indexed: 01/05/2023]
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Abstract
Neurotrophic factors released by target tissues maintain the survival and differentiation of innervating neurons. The manner by which these target-derived neurotrophic proteins communicate with innervating neurons has been actively pursued for over three decades. The present chapter describes a technique for preparing and maintaining compartmented chambers for culturing neurons derived from either superior cervical ganglia (sympathetic neurons) or dorsal root ganglia (sensory neurons). This system recapitulates the selective stimulation of neuron terminals that occurs in vivo following release of target-derived neurotrophins.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmacology and Anesthesiology, University of Padova, Padova, Italy.
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Calinescu AA, Liu T, Wang MM, Borjigin J. Transsynaptic activity-dependent regulation of axon branching and neurotrophin expression in vivo. J Neurosci 2011; 31:12708-15. [PMID: 21900550 PMCID: PMC3174489 DOI: 10.1523/jneurosci.2172-11.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 07/05/2011] [Accepted: 07/12/2011] [Indexed: 01/28/2023] Open
Abstract
The two major classes of activity-dependent neuroplasticity predict different consequences of activity alteration on circuit response. Hebbian plasticity (positive feedback) posits that alteration of neuronal activity causes a parallel response within a circuit. In contrast, homeostatic plasticity (negative feedback) predicts that altering neuronal activity results in compensatory responses within a circuit. The relative roles of these modes of plasticity in vivo are unclear, since neuronal circuits are difficult to manipulate in the intact organism. In this study, we tested the in vivo effects of activity deprivation in the superior cervical ganglion-pineal circuit of adult rats, which can be noninvasively silenced by exposing animals to constant light. We demonstrated that total deprivation of sympathetic activity markedly decreased the presence of axonal proteins in the pineal and reduced the density and thickness of sympathetic axonal arbors. In addition, we demonstrated that sympathetic inactivity eliminated pineal function and markedly decreased pineal expression of neurotrophins. Administration of β-adrenergic agonist restored the expression of presynaptic and postsynaptic proteins. Furthermore, compensatory axonal growth through collateral sprouting, normally seen following unilateral denervation of the pineal, was profoundly impaired in the absence of neural activity. Thus, these data suggest that sympathetic axonal terminals are maintained by neural activity that induces neurotrophins, which may act through a retrograde mechanism to preserve the integrity of axonal arbors via a positive feedback loop. Conversely, by using Hebbian-like neuroplasticity, silent yet intact circuits enter a hibernation mode marked by reduction of presynaptic axonal structures and dramatically reduced postsynaptic expression of neurotrophins.
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Affiliation(s)
| | - Tiecheng Liu
- Department of Molecular and Integrative Physiology and
| | - Michael M. Wang
- Department of Molecular and Integrative Physiology and
- Department of Neurology, University of Michigan Medical School, and
- Veterans Administration Ann Arbor Healthcare System, Ann Arbor, Michigan 48109-5622
| | - Jimo Borjigin
- Department of Molecular and Integrative Physiology and
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Ch'ng TH, Martin KC. Synapse-to-nucleus signaling. Curr Opin Neurobiol 2011; 21:345-52. [PMID: 21349698 DOI: 10.1016/j.conb.2011.01.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Revised: 01/31/2011] [Accepted: 01/31/2011] [Indexed: 12/21/2022]
Abstract
Signals generated in distal subcellular compartments of neurons must often travel long distances to the nucleus to trigger changes in gene expression. This retrograde signaling is critical to the development, function, and survival of neural circuits, and neurons have evolved multiple mechanisms to transmit signals over long distances. In this review, we briefly summarize the range of mechanisms whereby distally generated signals are transported to neuronal nuclei. We then focus on the transport of soluble signals from the synapse to the nucleus during neuronal plasticity.
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Affiliation(s)
- Toh Hean Ch'ng
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1737, United States
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Dahlstrom AB. Fast intra-axonal transport: Beginning, development and post-genome advances. Prog Neurobiol 2010; 90:119-45. [DOI: 10.1016/j.pneurobio.2009.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 11/23/2009] [Accepted: 11/23/2009] [Indexed: 01/02/2023]
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20
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Campenot RB, Lund K, Mok SA. Production of compartmented cultures of rat sympathetic neurons. Nat Protoc 2009; 4:1869-87. [DOI: 10.1038/nprot.2009.210] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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21
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Abstract
The cell body of a lesioned neuron must receive accurate and timely information on the site and extent of axonal damage, in order to mount an appropriate response. Specific mechanisms must therefore exist to transmit such information along the length of the axon from the lesion site to the cell body. Three distinct types of signals have been postulated to underlie this process, starting with injury-induced discharge of axon potentials, and continuing with two distinct types of retrogradely transported macromolecular signals. The latter includes, on the one hand, an interruption of the normal supply of retrogradely transported trophic factors from the target, and, on the other hand, activated proteins originating from the injury site. This chapter reviews the progress on understanding the different mechanistic aspects of the axonal response to injury, and how the information is conveyed from the injury site to the cell body to initiate regeneration.
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Affiliation(s)
- Keren Ben-Yaakov
- Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
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