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Sekine K, Haga W, Kim S, Imayasu M, Yoshida T, Tsutsui H. Neuron-microelectrode junction induced by an engineered synapse organizer. Biochem Biophys Res Commun 2024; 712-713:149935. [PMID: 38626529 DOI: 10.1016/j.bbrc.2024.149935] [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: 03/06/2024] [Revised: 04/04/2024] [Accepted: 04/11/2024] [Indexed: 04/18/2024]
Abstract
The conventional microelectrodes for recording neuronal activities do not have innate selectivity to cell type, which is one of the critical limitations for the detailed analysis of neuronal circuits. In this study, we engineered a downsized variant of the artificial synapse organizer based on neurexin1β and a peptide-tag, fabricated gold microelectrodes functionalized with the receptor for the organizer, and performed validation experiments in primary cultured neurons. Successful inductions of synapse-like junctions were detected at the sites of contact between neurons expressing the engineered synapse organizer and functionalized microelectrodes, but not in the negative control experiment in which the electrode functionalization was omitted. Such a molecularly inducible neuron-microelectrode junction could be the basis for the next-generation electrophysiological technique enabling cell type-selective recording.
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Affiliation(s)
- Kosuke Sekine
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Wataru Haga
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Samyoung Kim
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Mieko Imayasu
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, Toyama, 930-0194, Japan
| | - Hidekazu Tsutsui
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan; Division of Transdisciplinary Sciences, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan.
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Yang S, Wu J, Xian X, Chen Q. Isolation, culture, and characterization of duck primary neurons. Poult Sci 2023; 102:102485. [PMID: 36689785 PMCID: PMC9876984 DOI: 10.1016/j.psj.2023.102485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/01/2023] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
The duck is a representative and good model for studying the development and physiological mechanisms of the nervous system (NS) in waterfowl. Neurons are the basic structural and functional units of NS, but there is no detailed method for cultured duck neurons in vitro. An efficient and simple method for duck neuron culture is reported in this study. First, the sfigpecific markers (NSE and GFAP, respectively) were used to explore the timing of the development of neurons and astrocytes during the duck embryonic stage (E5-E18). The cytomorphology of tissues and cells was tracked with the microscope at different time points. The brain tissues from 10-day-old duck embryos were determined as the optimal sampling embryo age for neuron culture. Then, the brain tissue isolation method (papain digestion) and cell suspension inoculation density (7 × 105 cells/mL) were identified as the culture protocol to obtain target cells with high viability and high density. The purity of the cultured neurons was more than 95%. This experiment provides a supplement for the study of in vitro culture of waterfowl neurons and lays a good foundation for various subsequent studies.
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Affiliation(s)
| | | | | | - Qiusheng Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China.
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Ponsford AH, Ryan TA, Raimondi A, Cocucci E, Wycislo SA, Fröhlich F, Swan LE, Stagi M. Live imaging of intra-lysosome pH in cell lines and primary neuronal culture using a novel genetically encoded biosensor. Autophagy 2021; 17:1500-1518. [PMID: 32515674 PMCID: PMC8205096 DOI: 10.1080/15548627.2020.1771858] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 12/11/2022] Open
Abstract
Disorders of lysosomal physiology have increasingly been found to underlie the pathology of a rapidly growing cast of neurodevelopmental disorders and sporadic diseases of aging. One cardinal aspect of lysosomal (dys)function is lysosomal acidification in which defects trigger lysosomal stress signaling and defects in proteolytic capacity. We have developed a genetically encoded ratiometric probe to measure lysosomal pH coupled with a purification tag to efficiently purify lysosomes for both proteomic and in vitro evaluation of their function. Using our probe, we showed that lysosomal pH is remarkably stable over a period of days in a variety of cell types. Additionally, this probe can be used to determine that lysosomal stress signaling via TFEB is uncoupled from gross changes in lysosomal pH. Finally, we demonstrated that while overexpression of ARL8B GTPase causes striking alkalinization of peripheral lysosomes in HEK293 T cells, peripheral lysosomes per se are no less acidic than juxtanuclear lysosomes in our cell lines.Abbreviations: ARL8B: ADP ribosylation factor like GTPase 8B; ATP: adenosine triphosphate; ATP5F1B/ATPB: ATP synthase F1 subunit beta; ATP6V1A: ATPase H+ transporting V1 subunit A; Baf: bafilomycin A1; BLOC-1: biogenesis of lysosome-related organelles complex 1; BSA: bovine serum albumin; Cos7: African green monkey kidney fibroblast-like cell line; CQ: chloroquine; CTSB: cathepsin B; CYCS: cytochrome c, somatic; DAPI: 4',6-diamidino -2- phenylindole; DIC: differential interference contrast; DIV: days in vitro; DMEM: Dulbecco's modified Eagle's medium; E8: embryonic day 8; EEA1: early endosome antigen 1; EGTA: ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid; ER: endoplasmic reticulum; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; GABARAPL2: GABA type A receptor associated protein like 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GOLGA2/GM130: golgin A2; GTP: guanosine triphosphate; HEK293T: human embryonic kidney 293 cells, that expresses a mutant version of the SV40 large T antigen; HeLa: Henrietta Lacks-derived cell; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; HRP: horseradish peroxidase; IGF2R/ciM6PR: insulin like growth factor 2 receptor; LAMP1/2: lysosomal associated membrane protein 1/2; LMAN2/VIP36: lectin, mannose binding 2; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTORC1: mechanistic target of rapamycin kinase complex 1; PCR: polymerase chain reaction; PDL: poly-d-lysine; PGK1p: promotor from human phosphoglycerate kinase 1; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PPT1/CLN1: palmitoyl-protein thioesterase 1; RPS6KB1/p70: ribosomal protein S6 kinase B1; STAT3: signal transducer and activator of transcription 3; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGN: trans-Golgi network; TGOLN2/TGN46: trans-Golgi network protein 2; TIRF: total internal reflection fluorescence; TMEM106B: transmembrane protein 106B; TOR: target of rapamycin; TRPM2: transient receptor potential cation channel subfamily M member 2; V-ATPase: vacuolar-type proton-translocating ATPase; VPS35: VPS35 retromer complex component.
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Affiliation(s)
- Amy H. Ponsford
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Thomas A. Ryan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Andrea Raimondi
- Experimental Imaging Center, San Raffaele Scientific Institute, Milan, Italy
| | - Emanuele Cocucci
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and the Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Susanne A. Wycislo
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
- Centre of Cellular Nanoanalytics (CellNanOs), University of Osnabrück, Osnabrück, Osnabrück, Germany
| | - Laura E. Swan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Erdman N, Schmidt L, Yang X, Wei L, Xi T, Shao Y, Gao BZ. A microfabricated on-chip approach to the micropipette growth cone-turning assay. Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa8a42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kuang SY, Yang X, Wang Z, Huang T, Kindy M, Xi T, Gao BZ. How Microelectrode Array-Based Chick Forebrain Neuron Biosensors Respond to Glutamate NMDA Receptor Antagonist AP5 and GABA A Receptor Antagonist Musimol. SENSING AND BIO-SENSING RESEARCH 2016; 10:9-14. [PMID: 27551670 DOI: 10.1016/j.sbsr.2016.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We have established a long-term, stable primary chick forebrain neuron (FBN) culture on a microelectrode array platform as a biosensor system for neurotoxicant screening and for neuroelectrophysiological studies for multiple purposes. This paper reports some of our results, which characterize the biosensor pharmacologically. Dose-response experiments were conducted using NMDA receptor antagonist AP5 and GABAA receptor agonist musimol (MUS). The chick FBN biosensor (C-FBN-biosensor) responds to the two agents in a pattern similar to that of rodent counterparts; the estimated EC50s (the effective concentration that causes 50% inhibition of the maximal effect) are 2.3 μM and 0.25 μM, respectively. Intercultural and intracultural reproducibility and long-term reusability of the C-FBN-biosensor are addressed and discussed. A phenomenon of sensitization of the biosensor that accompanies intracultural reproducibility in paired dose-response experiments for the same agent (AP5 or MUS) is reported. The potential application of the C-FBN-biosensor as an alternative to rodent biosensors in shared sensing domains (NMDA receptor and GABAA receptor) is suggested.
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Cationic, amphiphilic copolymer micelles as nucleic acid carriers for enhanced transfection in rat spinal cord. Acta Biomater 2016; 35:98-108. [PMID: 26873365 DOI: 10.1016/j.actbio.2016.02.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 02/02/2016] [Accepted: 02/08/2016] [Indexed: 02/08/2023]
Abstract
Spinal cord injury commonly leads to permanent motor and sensory deficits due to the limited regenerative capacity of the adult central nervous system (CNS). Nucleic acid-based therapy is a promising strategy to deliver bioactive molecules capable of promoting axonal regeneration. Branched polyethylenimine (bPEI: 25kDa) is one of the most widely studied nonviral vectors, but its clinical application has been limited due to its cytotoxicity and low transfection efficiency in the presence of serum proteins. In this study, we synthesized cationic amphiphilic copolymers, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP), by grafting low molecular weight PLGA (4kDa) to bPEI (25kDa) at approximately a 3:1 ratio as an efficient nonviral vector. We show that PgP micelle is capable of efficiently transfecting plasmid DNA (pDNA) and siRNA in the presence of 10% serum in neuroglioma (C6) cells, neuroblastoma (B35) cells, and primary E8 chick forebrain neurons (CFN) with pDNA transfection efficiencies of 58.8%, 75.1%, and 8.1%, respectively. We also show that PgP provides high-level transgene expression in the rat spinal cord in vivo that is substantially greater than that attained with bPEI. The combination of improved transfection and reduced cytotoxicity in vitro in the presence of serum and in vivo transfection of neural cells relative to conventional bPEI suggests that PgP may be a promising nonviral vector for therapeutic nucleic acid delivery for neural regeneration. STATEMENT OF SIGNIFICANCE Gene therapy is a promising strategy to overcome barriers to axonal regeneration in the injured central nervous system. Branched polyethylenimine (bPEI: 25kDa) is one of the most widely studied nonviral vectors, but its clinical application has been limited due to cytotoxicity and low transfection efficiency in the presence of serum proteins. Here, we report cationic amphiphilic copolymers, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP) that are capable of efficiently transfecting reporter genes and siRNA both in the presence of 10% serum in vitro and in the rat spinal cord in vivo. The combination of improved transfection and reduced cytotoxicity in the presence of serum as well as transfection of neural cells in vivo suggests PgP may be a promising nucleic acid carrier for CNS gene delivery.
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Huang T, Wang Z, Wei L, Kindy M, Zheng Y, Xi T, Gao BZ. Microelectrode Array-evaluation of Neurotoxic Effects of Magnesium as an Implantable Biomaterial. JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY 2016; 32:89-96. [PMID: 27110081 PMCID: PMC4840281 DOI: 10.1016/j.jmst.2015.08.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Magnesium (Mg)-based biomaterials have shown great potential in clinical applications. However, the cytotoxic effects of excessive Mg2+ and the corrosion products from Mg-based biomaterials, particularly their effects on neurons, have been little studied. Although viability tests are most commonly used, a functional evaluation is critically needed. Here, both methyl thiazolyl tetrazolium (MTT) and lactate dehydrogenase (LDH) assays were used to test the effect of Mg2+ and Mg-extract solution on neuronal viability. Microelectrode arrays (MEAs), which provide long-term, real-time recording of extracellular electrophysiological signals of in vitro neuronal networks, were used to test for toxic effects. The minimum effective concentrations (ECmin) of Mg2+ from the MTT and LDH assays were 3 mmol/L and 100 mmol/L, respectively, while the ECmin obtained from the MEA assay was 0.1 mmol/L. MEA data revealed significant loss of neuronal network activity when the culture was exposed to 25% Mg-extract solution, a concentration that did not affect neuronal viability. For evaluating the biocompatibility of Mg-based biomaterials with neurons, MEA electrophysiological testing is a more precise method than basic cell-viability testing.
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Affiliation(s)
- Ting Huang
- Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Zhonghai Wang
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Lina Wei
- Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Mark Kindy
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
- Departments of Neurosciences and Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29466, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC 29403, USA
| | - Yufeng Zheng
- Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Tingfei Xi
- Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Shenzhen Key Laboratory of Human Tissue Regeneration and Repair, Shenzhen Institute, Peking University, Shenzhen 518057, China
| | - Bruce Z. Gao
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
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Ohara Y, Koganezawa N, Yamazaki H, Roppongi RT, Sato K, Sekino Y, Shirao T. Early-stage development of human induced pluripotent stem cell-derived neurons. J Neurosci Res 2015; 93:1804-13. [PMID: 26346430 PMCID: PMC5049656 DOI: 10.1002/jnr.23666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 08/03/2015] [Accepted: 08/22/2015] [Indexed: 01/16/2023]
Abstract
Recent advances in human induced pluripotent stem cells (hiPSCs) offer new possibilities for biomedical research and clinical applications. Differentiated neurons from hiPSCs are expected to be useful for developing novel methods of treatment for various neurological diseases. However, the detailed process of functional maturation of hiPSC-derived neurons (hiPS neurons) remains poorly understood. This study analyzes development of hiPS neurons, focusing specifically on early developmental stages through 48 hr after cell seeding; development was compared with that of primary cultured neurons derived from the rat hippocampus. At 5 hr after cell seeding, neurite formation occurs in a similar manner in both neuronal populations. However, very few neurons with axonal polarization were observed in the hiPS neurons even after 48 hr, indicating that hiPS neurons differentiate more slowly than rat neurons. We further investigated the elongation speed of axons and found that hiPS neuronal axons were slower. In addition, we characterized the growth cones. The localization patterns of skeletal proteins F-actin, microtubule, and drebrin were similar to those of rat neurons, and actin depolymerization by cytochalasin D induced similar changes in cytoskeletal distribution in the growth cones between hiPS neurons and rat neurons. These results indicate that, during the very early developmental stage, hiPS neurons develop comparably to rat hippocampal neurons with regard to axonal differentiation, but the growth of axons is slower.
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Affiliation(s)
- Yuki Ohara
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Noriko Koganezawa
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Hiroyuki Yamazaki
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Reiko T Roppongi
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Kaoru Sato
- Division of Pharmacology, National Institute of Health Sciences, Tokyo, Japan
| | - Yuko Sekino
- Division of Pharmacology, National Institute of Health Sciences, Tokyo, Japan
| | - Tomoaki Shirao
- Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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Abstract
Neurons begin their life as simple spheres, but can ultimately assume an elaborate morphology with numerous, highly arborized dendrites, and long axons. This is achieved via an astounding developmental progression which is dependent upon regulated assembly and dynamics of the cellular cytoskeleton. As neurites emerge out of the soma, neurons break their spherical symmetry and begin to acquire the morphological features that define their structure and function. Neurons regulate their cytoskeleton to achieve changes in cell shape, velocity, and direction as they migrate, extend neurites, and polarize. Of particular importance, the organization and dynamics of actin and microtubules directs the migration and morphogenesis of neurons. This review focuses on the regulation of intrinsic properties of the actin and microtubule cytoskeletons and how specific cytoskeletal structures and dynamics are associated with the earliest phase of neuronal morphogenesis—neuritogenesis.
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Kuang SY, Huang T, Wang Z, Lin Y, Kindy M, Xi T, Gao BZ. Establishment of a Long-Term Chick Forebrain Neuronal Culture on a Microelectrode Array Platform. RSC Adv 2015; 5:56244-56254. [PMID: 26989485 PMCID: PMC4792308 DOI: 10.1039/c5ra09663d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The biosensor system formed by culturing primary animal neurons on a microelectrode array (MEA) platform is drawing an increasing research interest for its power as a rapid, sensitive, functional neurotoxicity assessment, as well as for many other electrophysiological related research purposes. In this paper, we established a long-term chick forebrain neuron culture (C-FBN-C) on MEAs with a more than 5 month long lifespan and up to 5 month long stability in morphology and physiological function; characterized the C-FBN-C morphologically, functionally, and developmentally; partially compared its functional features with rodent counterpart; and discussed its pros and cons as a novel biosensor system in comparison to rodent counterpart and human induced pluripotent stem cells (hiPSCs). Our results show that C-FBN-C on MEA platform 1) can be used as a biosensor of its own type in a wide spectrum of basic biomedical research; 2) is of value in comparative physiology in cross-species studies; and 3) may have potential to be used as an alternative, cost-effective approach to rodent counterpart within shared common functional domains (such as specific types of ligand-gated ion channel receptors and subtypes expressed in the cortical tissues of both species) in large-scale environmental neurotoxicant screening that would otherwise require millions of animals.
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Affiliation(s)
- Serena Y. Kuang
- William Beaumont School of Medicine, Oakland University, Rochester, MI 49309, USA
| | - Ting Huang
- Academy for Advanced Interdisciplinary Studies, Center for Biomedical Materials and Tissue Engineering, Peking University, Beijing, 100871, China
| | - Zhonghai Wang
- Department of Bioengineering, Clemson University, 201-5 Rhodes Research Hall, Clemson, SC 29634, USA
| | - Yongliang Lin
- National Engineering Laboratory for Regenerative Implantable Medical Devices, Guangzhou, Guangdong 510530, China
| | - Mark Kindy
- Departments of Neuroscience and Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29466, USA
| | - Tingfei Xi
- Academy for Advanced Interdisciplinary Studies, Center for Biomedical Materials and Tissue Engineering, Peking University, Beijing, 100871, China
| | - Bruce Z. Gao
- Department of Bioengineering, Clemson University, 201-5 Rhodes Research Hall, Clemson, SC 29634, USA
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Prolonging life in chick forebrain-neuron culture and acquiring spontaneous spiking activity on a microelectrode array. Biotechnol Lett 2014; 37:499-509. [PMID: 25344105 DOI: 10.1007/s10529-014-1704-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/14/2014] [Indexed: 01/09/2023]
Abstract
Various types of animal neurons were cultured on a microelectrode array (MEA) platform to form biosensors to detect potential environmental neurotoxins. For a large-scale screening tool, rodent MEA-based cortical-neuron biosensors would be very costly but chick forebrain neurons (FBNs) are abundant, cost-effective, and easy to dissect. However, chick FBNs have a lifespan of ~14 days in vitro and their spontaneous spike activity (SSA) has been difficult to develop and detect. We used a high-density neuron-glia co-culture on an MEA to prolong chick FBN lifetime to 3 months with lifetime-long SSA. A remarkable embryonic age-dependency in the culture's morphology, lifespan, and most features of SSA signal was discovered. Our results show the feasibility of developing a chick FBN-MEA biosensor and also establish a new electrophysiological platform for functional study of an in vitro neuronal network.
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Wei L, Sweeney AJ, Sheng L, Fang Y, Kindy MS, Xi T, Gao BZ. Single-neuron axonal pathfinding under geometric guidance: low-dose-methylmercury developmental neurotoxicity test. LAB ON A CHIP 2014; 14:3564-71. [PMID: 25041816 PMCID: PMC4148692 DOI: 10.1039/c4lc00723a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Because the nervous system is most vulnerable to toxicants during development, there is a crucial need for a highly sensitive developmental-neurotoxicity-test model to detect potential toxicants at low doses. We developed a lab-on-chip wherein single-neuron axonal pathfinding under geometric guidance was created using soft lithography and laser cell-micropatterning techniques. After coating the surface with L1, an axon-specific member of the Ig family of cell adhesion molecules (CAMs), and optimizing microunit geometric parameters, we introduced low-dose methylmercury, a well-known, environmentally significant neurotoxicant, in the shared medium. Its developmental neurotoxicity was evaluated using a novel axonal pathfinding assay including axonal turning and branching rates at turning points in this model. Compared to the conventional neurite-outgrowth assay, this model's detection threshold for low-dose methylmercury was 10-fold more sensitive at comparable exposure durations. These preliminary results support study of developmental effects of known and potential neurotoxicants on axon pathfinding. This novel assay model would be useful to study neuronal disease mechanisms at the single-cell level. To our knowledge, the potential of methylmercury chloride to cause acute in vitro developmental neurotoxicity (DNT) at such a low dosage has not been reported. This is the first DNT test model with high reproducibility to use single-neuron axonal pathfinding under precise geometric guidance.
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Affiliation(s)
- Lina Wei
- Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Andrew J. Sweeney
- Biophotonics Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
| | - Liyuan Sheng
- Shenzhen Key Laboratory of Human Tissue Regeneration and Repair, Shenzhen Institute, Peking University, Shenzhen 518057, China
| | - Yu Fang
- Division of Standardization & Science Research, Institute for Medical Devices Control, National Institute for Food and Drug Control, Beijing 100050, China
| | - Mark S. Kindy
- Biophotonics Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
- Departments of Neurosciences and Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29466, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC, 29403, USA
| | - Tingfei Xi
- Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Shenzhen Key Laboratory of Human Tissue Regeneration and Repair, Shenzhen Institute, Peking University, Shenzhen 518057, China
| | - Bruce Z. Gao
- Biophotonics Laboratory, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
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Erdman N, Schmidt L, Qin W, Yang X, Lin Y, DeSilva MN, Gao BZ. Microfluidics-based laser cell-micropatterning system. Biofabrication 2014; 6:035025. [PMID: 25190714 PMCID: PMC4354940 DOI: 10.1088/1758-5082/6/3/035025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The ability to place individual cells into an engineered microenvironment in a cell-culture model is critical for the study of in vivo relevant cell-cell and cell-extracellular matrix interactions. Microfluidics provides a high-throughput modality to inject various cell types into a microenvironment. Laser guided systems provide the high spatial and temporal resolution necessary for single-cell micropatterning. Combining these two techniques, the authors designed, constructed, tested and evaluated (1) a novel removable microfluidics-based cell-delivery biochip and (2) a combined system that uses the novel biochip coupled with a laser guided cell-micropatterning system to place individual cells into both two-dimensional (2D) and three-dimensional (3D) arrays. Cell-suspensions of chick forebrain neurons and glial cells were loaded into their respective inlet reservoirs and traversed the microfluidic channels until reaching the outlet ports. Individual cells were trapped and guided from the outlet of a microfluidic channel to a target site on the cell-culture substrate. At the target site, 2D and 3D pattern arrays were constructed with micron-level accuracy. Single-cell manipulation was accomplished at a rate of 150 μm s(-1) in the radial plane and 50 μm s(-1) in the axial direction of the laser beam. Results demonstrated that a single-cell can typically be patterned in 20-30 s, and that highly accurate and reproducible cellular arrays and systems can be achieved through coupling the microfluidics-based cell-delivery biochip with the laser guided system.
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Affiliation(s)
- Nick Erdman
- Clemson University, Department of Bioengineering, Clemson, South Carolina 29634, USA
| | - Lucas Schmidt
- Clemson University, Department of Bioengineering, Clemson, South Carolina 29634, USA
| | - Wan Qin
- Clemson University, Department of Bioengineering, Clemson, South Carolina 29634, USA
| | - Xiaoqi Yang
- Clemson University, Department of Bioengineering, Clemson, South Carolina 29634, USA
| | - Yongliang Lin
- National Engineering Laboratory for Regenerative Implantable Medical Devices, Guangzhou, Guangdong 510530, China
| | - Mauris N DeSilva
- Naval Medical Research Unit San Antonio, JBSA Fort Sam Houston, Texas 78234, USA
| | - Bruce Z. Gao
- Clemson University, Department of Bioengineering, Clemson, South Carolina 29634, USA
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14
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Angioneural crosstalk in scaffolds with oriented microchannels for regenerative spinal cord injury repair. J Mol Neurosci 2012; 49:334-46. [PMID: 22878912 DOI: 10.1007/s12031-012-9863-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/23/2012] [Indexed: 01/15/2023]
Abstract
The aim of our work is to utilize the crosstalk between the vascular and the neuronal system to enhance directed neuritogenesis in uniaxial guidance scaffolds for the repair of spinal cord injury. In this study, we describe a method for angioneural regenerative engineering, i.e., for generating biodegradable scaffolds, produced by a combination of controlled freezing (freeze-casting) and lyophilization, which contain longitudinally oriented channels, and provide uniaxial directionality to support and guide neuritogenesis from neuronal cells in the presence of endothelial cells. The optimized scaffolds, composed of 2.5 % gelatin and 1 % genipin crosslinked, were characterized by an elastic modulus of ~51 kPa and longitudinal channels of ~50 μm diameter. The scaffolds support the growth of endothelial cells, undifferentiated or NGF-differentiated PC12 cells, and primary cultures of fetal chick forebrain neurons. The angioneural crosstalk, as generated by first forming endothelial cell monolayers in the scaffolds followed by injection of neuronal cells, leads to the outgrowth of long aligned neurites in the PC12/endothelial cell co-cultures also in the absence of exogenously added nerve growth factor. Neuritogenesis was not observed in the scaffolds in the absence of the endothelial cells. This methodology is a promising approach for neural tissue engineering and may be applicable for regenerative spinal cord injury repair.
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15
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The effects of energy beverages on cultured cells. Food Chem Toxicol 2012; 50:3759-68. [PMID: 22809471 DOI: 10.1016/j.fct.2012.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 06/30/2012] [Accepted: 07/05/2012] [Indexed: 01/22/2023]
Abstract
The popularity and prevalence of energy beverages makes it essential to examine the interactions between the ingredients and their effects on the safety of these beverages. In this study, we used in vitro assays to examine the effects of two energy beverages on mesenchymal, epithelial and neuronal cells. Our results showed that treatment of epithelial and mesenchymal cells with either energy beverage resulted in a dose dependent delay in wound closure, in a scratch wound healing assay. In rat embryonic fibroblasts, treatment with the energy beverages led to decreased lamellipodia formation and decreased proliferation/viability; whereas in MDCK cells, energy beverage treatment resulted in actin disorganization without any effects on cell proliferation. This suggests that the mechanisms underlying delayed wound healing might be different in the two cell types. Interestingly, the delays in both cell types could not be mimicked by treatment of caffeine, taurine and glucose alone or in combinations. Furthermore, treatment of chick forebrain neuronal cultures with energy beverages resulted in a dose dependent inhibition of neurite outgrowth. The cellular assays used in this study provide a consistent, qualitative and quantitative system for examining the combinatorial effects of the various ingredients used in energy beverages.
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16
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Pirlo RK, Sweeney AJ, Ringeisen BR, Kindy M, Gao BZ. Biochip∕laser cell deposition system to assess polarized axonal growth from single neurons and neuron∕glia pairs in microchannels with novel asymmetrical geometries. BIOMICROFLUIDICS 2011; 5:13408. [PMID: 21522498 PMCID: PMC3082345 DOI: 10.1063/1.3552998] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 12/18/2010] [Indexed: 05/20/2023]
Abstract
Axon path-finding plays an important role in normal and pathogenic brain development as well as in neurological regenerative medicine. In both scenarios, axonal growth is influenced by the microenvironment including the soluble molecules and contact-mediated signaling from guiding cells and cellular matrix. Microfluidic devices are a powerful tool for creating a microenvironment at the single cell level. In this paper, an asymmetrical-channel-based biochip, which can be later incorporated into microfluidic devices for neuronal network study, was developed to investigate geometric as well as supporting cell control of polarized axonal growth in forming a defined neuronal circuitry. A laser cell deposition system was used to place single cells, including neuron-glia pairs, into specific microwells of the device, enabling axonal growth without the influence of cytophilic∕phobic surface patterns. Phase microscopy showed that a novel "snag" channel structure influenced axonal growth in the intended direction 4:1 over the opposite direction. In heterotypic experiments, glial cell influence over the axonal growth path was observed with time-lapse microscopy. Thus, it is shown that single cell and heterotypic neuronal path-finding models can be developed in laser patterned biochips.
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17
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Seetapun D, Odde DJ. Cell-length-dependent microtubule accumulation during polarization. Curr Biol 2010; 20:979-88. [PMID: 20493705 DOI: 10.1016/j.cub.2010.04.040] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 04/19/2010] [Accepted: 04/21/2010] [Indexed: 01/03/2023]
Abstract
BACKGROUND Breaking cell symmetry, known as polarization, requires dynamic reorganization of microtubules (MTs) and is essential to many cellular processes, including axon formation in neurons. A critical step in polarization is believed to be the "selective stabilization" of MTs, which hypothesizes a spatial and/or temporal shift toward net MT assembly in a preferred direction of growth. RESULTS We now find that a simpler "length-dependent" model, in which MT assembly parameters are spatially and temporally constant, predicts MT accumulation in the direction of growth because of longer mean first passage times in the longer direction. We experimentally tested both models by tracking MT assembly dynamics in polarizing embryonic chick forebrain neurons, and we confirmed that assembly is spatially and temporally constant during axon formation. CONCLUSION Cell polarization occurs most simply through cell-length-dependent accumulation of MTs without MT stabilization or capture. In this way, F-actin-mediated cell shape and size changes can be read out by dynamic MTs undergoing simple dynamic instability to ultimately break cell symmetry.
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Affiliation(s)
- Dominique Seetapun
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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18
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Flynn KC, Pak CW, Shaw AE, Bradke F, Bamburg JR. Growth cone-like waves transport actin and promote axonogenesis and neurite branching. Dev Neurobiol 2009; 69:761-79. [PMID: 19513994 DOI: 10.1002/dneu.20734] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Axonogenesis involves a shift from uniform delivery of materials to all neurites to preferential delivery to the putative axon, supporting its more rapid extension. Waves, growth cone-like structures that propagate down the length of neurites, were shown previously to correlate with neurite growth in dissociated cultured hippocampal neurons. Waves are similar to growth cones in their structure, composition and dynamics. Here, we report that waves form in all undifferentiated neurites, but occur more frequently in the future axon during initial neuronal polarization. Moreover, wave frequency and their impact on neurite growth are altered in neurons treated with stimuli that enhance axonogenesis. Coincident with wave arrival, growth cones enlarge and undergo a marked increase in dynamics. Through their engorgement of filopodia along the neurite shaft, waves can induce de novo neurite branching. Actin in waves maintains much of its cohesiveness during transport whereas actin in nonwave regions of the neurite rapidly diffuses as measured by live cell imaging of photoactivated GFP-actin and photoconversion of Dendra-actin. Thus, waves represent an alternative axonal transport mechanism for actin. Waves also occur in neurons in organotypic hippocampal slices where they propagate along neurites in the dentate gyrus and the CA regions and induce branching. Taken together, our results indicate that waves are physiologically relevant and contribute to axon growth and branching via the transport of actin and by increasing growth cone dynamics.
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Affiliation(s)
- Kevin C Flynn
- Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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19
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Mechanical membrane injury induces axonal beading through localized activation of calpain. Exp Neurol 2009; 219:553-61. [PMID: 19619536 DOI: 10.1016/j.expneurol.2009.07.014] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 07/09/2009] [Accepted: 07/13/2009] [Indexed: 12/31/2022]
Abstract
Diffuse axonal injury (DAI), a major component of traumatic brain injury, is characterized by a sequence of neurochemical reactions initiated at the time of trauma and resulting in axonal degeneration and cell death. Calcium influx through mechanically induced axolemmal pores and subsequent activation of calpains are thought to be responsible for the cytoskeletal damage leading to impaired axonal transport. Focal disruption of cytoskeleton accompanied by the accumulation of transported membranous cargo leads to axonal beading which is the characteristic morphology of DAI. By applying fluid shear stress injury on cultured primary neurons, acute calcium (Ca(2+)) and calpain responses of axons to mechanical trauma were investigated. Intracellular Ca(2+) concentration ([Ca(2+)](i)) shows a steady increase following injury that can be blocked by sealing membrane pores with Poloxamer 188 and by chelating intra- or extracellular Ca(2+). Calpain activity increases in response to mechanical injury and this increase depends on Ca(2+) availability and on axolemmal permeability. Both the [Ca(2+)](i) increase and calpain activity exhibit focal peaks along the axons which co-localize with mitochondria and predict future axonal bead locations. These findings suggest that mechanoporation may be the initiating mechanism resulting in ensuing calcium fluxes and subsequent calpain activity and that post-injury membrane repair may be a valid therapeutic approach for acute intervention in DAI.
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20
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Kollins KM, Hu J, Bridgman PC, Huang YQ, Gallo G. Myosin-II negatively regulates minor process extension and the temporal development of neuronal polarity. Dev Neurobiol 2009; 69:279-98. [PMID: 19224562 DOI: 10.1002/dneu.20704] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The earliest stage in the development of neuronal polarity is characterized by extension of undifferentiated "minor processes" (MPs), which subsequently differentiate into the axon and dendrites. We investigated the role of the myosin II motor protein in MP extension using forebrain and hippocampal neuron cultures. Chronic treatment of neurons with the myosin II ATPase inhibitor blebbistatin increased MP length, which was also seen in myosin IIB knockouts. Through live-cell imaging, we demonstrate that myosin II inhibition triggers rapid minor process extension to a maximum length range. Myosin II activity is determined by phosphorylation of its regulatory light chains (rMLC) and mediated by myosin light chain kinase (MLCK) or RhoA-kinase (ROCK). Pharmacological inhibition of MLCK or ROCK increased MP length moderately, with combined inhibition of these kinases resulting in an additive increase in MP length similar to the effect of direct inhibition of myosin II. Selective inhibition of RhoA signaling upstream of ROCK, with cell-permeable C3 transferase, increased both the length and number of MPs. To determine whether myosin II affected development of neuronal polarity, MP differentiation was examined in cultures treated with direct or indirect myosin II inhibitors. Significantly, inhibition of myosin II, MLCK, or ROCK accelerated the development of neuronal polarity. Increased myosin II activity, through constitutively active MLCK or RhoA, decreased both the length and number of MPs and, consequently, delayed or abolished the development of neuronal polarity. Together, these data indicate that myosin II negatively regulates MP extension, and the developmental time course for axonogenesis.
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Affiliation(s)
- K M Kollins
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA.
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21
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Francisco H, Kollins K, Varghis N, Vocadlo D, Vosseller K, Gallo G. O-GLcNAc post-translational modifications regulate the entry of neurons into an axon branching program. Dev Neurobiol 2009; 69:162-73. [PMID: 19086029 PMCID: PMC2747243 DOI: 10.1002/dneu.20695] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Many neuronal cytosolic and nuclear proteins are post-translationally modified by the reversible addition of O-linked N-acetylglucosamine (O-GlcNAc) on serines and threonines. The cellular functions of O-GlcNAc modifications in neuronal development are not known. We report that O-GlcNAc-modified proteins are distributed nonuniformly throughout cultured primary chicken forebrain neurons, with intense immunostaining of the cell body, punctuate immunostaining in axons and all processes, and localization in filopodia/lamellipodia. Overexpression of O-GlcNAcase, the enzyme that removes O-GlcNAc from proteins, increased the percentage of neurons exhibiting axon branching without altering the frequency of axon branches on a per neuron basis and increased the numbers of axonal filopodia. Conversely, pharmacologically increasing O-GlcNAc levels on proteins through specific inhibition of O-GlcNAcase with the inhibitor 9d decreased the numbers of axonal filopodia, but had no effect on axon length or branching. Treatment with an alternative O-GlcNAcase inhibitor, PUGNAc, similarly decreased the number of axonal filopodia. Furthermore, axon branching induced by the adenylyl cyclase activator forskolin was suppressed by pharmacological inhibition of O-GlcNAcase. Western analysis revealed that O-GlcNAc levels regulate the phosphorylation of some PKA substrates in response to forskolin. These data provide the first evidence of O-GlcNAc modification-specific influences in neuronal development in primary culture, and indicate specific roles for O-GlcNAc in the regulation of axon morphology. © 2008 Wiley Periodicals, Inc. Develop Neurobiol 69: 162–173, 2009
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Affiliation(s)
- Herb Francisco
- Department of Neurobiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA
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22
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Kilinc D, Gallo G, Barbee KA. Mechanically-induced membrane poration causes axonal beading and localized cytoskeletal damage. Exp Neurol 2008; 212:422-30. [DOI: 10.1016/j.expneurol.2008.04.025] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 04/14/2008] [Accepted: 04/20/2008] [Indexed: 10/22/2022]
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Kilinc D, Gallo G, Barbee K. Poloxamer 188 reduces axonal beading following mechanical trauma to cultured neurons. ACTA ACUST UNITED AC 2008; 2007:5395-8. [PMID: 18003228 DOI: 10.1109/iembs.2007.4353562] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Diffuse axonal injury (DAI), a major component of traumatic brain injury, is a progressive event that may lead to secondary neuronal death. DAI is thought to be initiated by mechanically-induced increases in axolemmal permeability resulting in disruption of the cytoskeleton and blockade of axonal transport. We report an in vitro model that mimics important features of DAI observed in vivo. We induced fluid shear stress injury (FSSI) on cultured primary chick forebrain neurons and characterized the resulting structural and morphological changes. In addition, we tested the post-injury effect of Poloxamer 188 (P188), a tri-block co-polymer that is known to promote resealing membrane pores. We found that FSSI induces axonal beading, the "hallmark" morphology of DAI. Furthermore, beads co-localized with microtubule disruption, also characteristic of DAI. P188 reduced axonal beading to control levels indicating that axolemma integrity is an excellent target for therapeutic interventions.
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24
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Baculovirus expression and bioactivity of a soluble 140kDa extracellular cleavage fragment of L1 neural cell adhesion molecule. Protein Expr Purif 2008; 57:172-9. [DOI: 10.1016/j.pep.2007.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 10/08/2007] [Accepted: 10/11/2007] [Indexed: 11/21/2022]
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25
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Sasoglu FM, Kilinc D, Allen K, Layton B. Towards a method for printing a network of chick forebrain neurons for biosensor applications. ACTA ACUST UNITED AC 2007; 2007:4092-5. [PMID: 18002901 DOI: 10.1109/iembs.2007.4353235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The primary goal of this work is to establish a robust, repeatable method for printing arrays of neurons. This work has two endpoints. One is to use a neural array as an experimental testbed for investigating neuronal cell growth hypotheses. The other endpoint is to enable the next generation of cell-based sensors. Herein we compare microcontact printing results previously published by our group with a new method of dip-pen printing. We present preliminary results for neurons growing on these microprinted arrays, assessing contact frequencies and growth characteristics.
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Affiliation(s)
- F Mert Sasoglu
- Drexel University, Department of Mechanical Engineering and Mechanics, Philadelphia, PA 19104, USA
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26
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Stahl AM, Ruthel G, Torres-Melendez E, Kenny TA, Panchal RG, Bavari S. Primary cultures of embryonic chicken neurons for sensitive cell-based assay of botulinum neurotoxin: implications for therapeutic discovery. ACTA ACUST UNITED AC 2007; 12:370-7. [PMID: 17332092 DOI: 10.1177/1087057106299163] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Botulinum toxin is an exceedingly potent inhibitor of neurotransmission across the neuromuscular junction, causing flaccid paralysis and death. The potential for misuse of this deadly poison as a bioweapon has added a greater urgency to the search for effective therapeutics. The development of sensitive and efficient cell-based assays for the evaluation of toxin antagonists is crucial to the rapid and successful identification of therapeutic compounds. The authors evaluated the sensitivity of primary cultures from 4 distinct regions of the embryonic chick nervous system to botulinum neurotoxin A (BoNT/A) cleavage of synaptosomal-associated protein of 25 kD (SNAP-25). Although differences in sensitivity were apparent, SNAP-25 cleavage was detectable in neuronal cells from each of the 4 regions within 3 h at BoNT/A concentrations of 1 nM or lower. Co-incubation of chick neurons with BoNT/A and toxin-neutralizing antibodies inhibited SNAP-25 cleavage, demonstrating the utility of these cultures for the assay of BoNT/A antagonists.
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Affiliation(s)
- Andrea M Stahl
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702, USA
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27
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Abstract
We have designed a laser cell deposition system that employs the phenomenon of laser guidance to place single cells at specific points in a variety of in vitro environments. Here, we describe the components of the system: the laser optics, the deposition chamber, the microinjection cell feeding system and our custom system control software application. We discuss the requirements and challenges involved in laser guidance of cells and how our present system overcomes these challenges. We demonstrate that the patterning system is accurate within one micrometer by repeatedly depositing polymer microspheres and measuring their position. We demonstrate its ability to create highly defined living patterns of cells by creating a defined pattern of neurons with neurite extensions displaying normal function. We found that the positional accuracy of our system is smaller than the variations in cell size and pattern disruptions that occur from normal cell movement during substrate adhesion. The laser cell deposition system is a potentially useful tool that can be used to achieve site- and time-specific placement of an individual cell in a cell culture for the systematic investigation of cell-cell and cell-extracellular matrix interactions.
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Affiliation(s)
- Russell K Pirlo
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
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28
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Tretyakova I, Zolotukhin AS, Tan W, Bear J, Propst F, Ruthel G, Felber BK. Nuclear Export Factor Family Protein Participates in Cytoplasmic mRNA Trafficking. J Biol Chem 2005; 280:31981-90. [PMID: 16014633 DOI: 10.1074/jbc.m502736200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In eukaryotes, the nuclear export of mRNA is mediated by nuclear export factor 1 (NXF1) receptors. Metazoans encode additional NXF1-related proteins of unknown function, which share homology and domain organization with NXF1. Some mammalian NXF1-related genes are expressed preferentially in the brain and are thought to participate in neuronal mRNA metabolism. To address the roles of NXF1-related factors, we studied the two mouse NXF1 homologues, mNXF2 and mNXF7. In neuronal cells, mNXF2, but not mNXF7, exhibited mRNA export activity similar to that of Tip-associated protein/NXF1. Surprisingly, mNXF7 incorporated into mobile particles in the neurites that contained poly(A) and ribosomal RNA and colocalized with Staufen1-containing transport granules, indicating a role in neuronal mRNA trafficking. Yeast two-hybrid interaction, coimmunoprecipitation, and in vitro binding studies showed that NXF proteins bound to brain-specific microtubule-associated proteins (MAP) such as MAP1B and the WD repeat protein Unrip. Both in vitro and in vivo, MAP1B also bound to NXF export cofactor U2AF as well as to Staufen1 and Unrip. These findings revealed a network of interactions likely coupling the export and cytoplasmic trafficking of mRNA. We propose a model in which MAP1B tethers the NXF-associated mRNA to microtubules and facilitates their translocation along dendrites while Unrip provides a scaffold for the assembly of these transport intermediates.
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Affiliation(s)
- Irina Tretyakova
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702, USA
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