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Zhang J, Liu Y, Lu L. Emerging role of MicroRNAs in peripheral nerve system. Life Sci 2018; 207:227-233. [PMID: 29894714 DOI: 10.1016/j.lfs.2018.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/21/2018] [Accepted: 06/08/2018] [Indexed: 01/17/2023]
Abstract
Peripheral nerve injury is one of the most common clinical diseases. Although the regeneration of the peripheral nerve is better than that of the nerves of the central nervous system, because of its growth rate restrictions after damage. Hence, the outcome of repair after injury is not favorable. Small RNA, a type of non-coding RNA, has recently been gaining attention in neural injury. It is widely distributed in the nervous system in vivo and a significant change in the expression of small RNAs has been observed in a neural injury model. This suggests that MicroRNAs (miRNAs) may serve as a potential target for resolving the challenges of peripheral nerve repair. This review summarizes the current challenges in peripheral nerve injury repair, systematically expounds the mechanism of miRNAs in the process of nerve injury and repair and attempts to determine the possible treatment of peripheral nerve injury.
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Affiliation(s)
- Jiayi Zhang
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China
| | - Yang Liu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China
| | - Laijin Lu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China.
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2
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Golan M, Zelinger E, Zohar Y, Levavi-Sivan B. Architecture of GnRH-Gonadotrope-Vasculature Reveals a Dual Mode of Gonadotropin Regulation in Fish. Endocrinology 2015; 156:4163-73. [PMID: 26261873 DOI: 10.1210/en.2015-1150] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The function and components of the hypothalamic-pituitary axis are conserved among vertebrates; however, in fish, a neuroglandular mode of delivery (direct contact between axons and endocrine cells) was considered dominant, whereas in tetrapods hypothalamic signals are relayed to their targets via the hypophysial portal blood system (neurovascular delivery mode). By using a transgenic zebrafish model we studied the functional and anatomical aspects of gonadotrope regulation thus revisiting the existing model. FSH cells were found to be situated close to the vasculature whereas the compact organization of LH cells prevented direct contact of all cells with the circulation. GnRH3 fibers formed multiple boutons upon reaching the pituitary, but most of these structures were located in the neurohypophysis rather than adjacent to gonadotropes. A close association was observed between FSH cells and GnRH3 boutons, but only a fifth of the LH cells were in direct contact with GnRH3 axons, suggesting that FSH cells are more directly regulated than LH cells. GnRH3 fibers closely followed the vasculature in the neurohypophysis and formed numerous boutons along these tracts. These vessels were found to be permeable to relatively large molecules, suggesting the uptake of GnRH3 peptides. Our findings have important implications regarding the differential regulation of LH and FSH and contradict the accepted notion that fish pituitary cells are mostly regulated directly by hypothalamic fibers. Instead, we provide evidence that zebrafish apply a dual mode of gonadotrope regulation by GnRH3 that combines both neuroglandular and neurovascular components.
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Affiliation(s)
- Matan Golan
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
| | - Einat Zelinger
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
| | - Yonathan Zohar
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
| | - Berta Levavi-Sivan
- Department of Animal Sciences (M.G., B.L.-S.) and The Interdepartmental Equipment Unit (E.Z.), The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; and Department of Marine Biotechnology (Y.Z.), University of Maryland Baltimore County and Institute of Marine and Environmental Technology, Baltimore, Maryland 21202
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Imaging Submillisecond Membrane Potential Changes from Individual Regions of Single Axons, Dendrites and Spines. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:57-101. [PMID: 26238049 PMCID: PMC5671121 DOI: 10.1007/978-3-319-17641-3_3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A central question in neuronal network analysis is how the interaction between individual neurons produces behavior and behavioral modifications. This task depends critically on how exactly signals are integrated by individual nerve cells functioning as complex operational units. Regional electrical properties of branching neuronal processes which determine the input-output function of any neuron are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor, at multiple sites, subthreshold events as they travel from the sites of origin (synaptic contacts on distal dendrites) and summate at particular locations to influence action potential initiation. It became possible recently to carry out this type of measurement using high-resolution multisite recording of membrane potential changes with intracellular voltage-sensitive dyes. This chapter reviews the development and foundation of the method of voltage-sensitive dye recording from individual neurons. Presently, this approach allows monitoring membrane potential transients from all parts of the dendritic tree as well as from axon collaterals and individual dendritic spines.
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Wu D, Murashov AK. Molecular mechanisms of peripheral nerve regeneration: emerging roles of microRNAs. Front Physiol 2013; 4:55. [PMID: 23554595 PMCID: PMC3612692 DOI: 10.3389/fphys.2013.00055] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/07/2013] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs are small non-coding RNAs that suppress gene expression through target mRNA degradation or translation repression. Recent studies suggest that miRNA plays an important role in multiple physiological and pathological processes in the nervous system. In this review article, we described what is currently known about the mechanisms in peripheral nerve regeneration on cellular and molecular levels. Recently, changes in microRNA expression profiles have been detected in different injury models, and emerging evidence strongly indicates that these changes promote neurons to survive by shifting their physiology from maintaining structure and supporting synaptic transmission towards a regenerative phenotype. We reviewed the putative mechanisms involved in miRNA mediated post-transcriptional regulation and pointed out several areas where future research is necessary to advance our understanding of how targeting miRNA machinery can be used as a therapeutic approach for treating nerve injuries.
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Affiliation(s)
- Di Wu
- Department of Physiology, East Carolina University Greenville, NC, USA ; Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
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Wu D, Raafat M, Pak E, Hammond S, Murashov AK. MicroRNA machinery responds to peripheral nerve lesion in an injury-regulated pattern. Neuroscience 2011; 190:386-97. [PMID: 21689732 DOI: 10.1016/j.neuroscience.2011.06.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 06/02/2011] [Indexed: 12/20/2022]
Abstract
Recently, functional and potent RNA interference (RNAi) has been reported in peripheral nerve axons transfected with short-interfering RNA (siRNA). In addition, components of RNA-induced silencing complex (RISC) have been identified in axotomized sciatic nerve fibers as well as in regenerating dorsal root ganglia (DRG) neurons in vitro. Based on these observations, and on the fact that siRNA and microRNA (miRNA) share the same effector enzymes, we hypothesized that the endogenous miRNA biosynthetic pathway would respond to peripheral nerve injury. To answer this question, we investigated changes in the expression of miRNA biosynthetic enzymes following peripheral nerve crush injury in mice. Here, we show that several pivotal miRNA biosynthetic enzymes are expressed in an injury-regulated pattern in sciatic nerve in vivo, and in DRG axons in vitro. Moreover, the sciatic nerve lesion induced expression of mRNA-processing bodies (P-bodies), which are the local foci of mRNA degradation in DRG axons. In addition, a group of injury-regulated miRNAs was identified by miRNA microarray and validated by real-time quantitative PCR (qPCR) and in situ hybridization analyses. Taken together, our data support the hypothesis that the peripheral nerve regeneration processes may be regulated by miRNA pathway.
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Affiliation(s)
- D Wu
- Department of Physiology, East Carolina University, Greenville, NC 27834, USA
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Ullrich C, Humpel C. Mini-ruby is rapidly taken up by neurons and astrocytes in organotypic brain slices. Neurochem Res 2011; 36:1817-23. [PMID: 21604155 DOI: 10.1007/s11064-011-0499-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2011] [Indexed: 10/18/2022]
Abstract
Cholinergic neurons are intensively studied, because they degenerate in Alzheimer's disease. Although neurotracer techniques are widely used to study axonal transport, guidance, regeneration or sprouting it is not clear if cholinergic neurons can be stained by tracer techniques and studied in brain slices. The aim of the present study was to evaluate the characteristics of the neurotracer Mini-ruby in organotypic brain slices of the basal nucleus of Meynert (nBM), focusing on cholinergic neurons. Mini-ruby is a biotinylated dextran amine and is taken up very fast by a variety of cells. When 2-week old nerve growth factor-incubated brain slices of the nBM were treated with Mini-ruby crystals for 1 h, only a few (2-3%) cholinergic neurons were clearly labeled as shown by co-localization with choline acetyltransferase. The staining was found in neuN-positive neurons and microtubule associated protein-2 (MAP-2)-positive nerve fibers. A very rapid dynamic change was observed in these labeled varicosities within seconds. However, Mini-ruby was taken up also by many glutamine synthethase-positive astrocytes. At the site of Mini-ruby application an intense CD11b-positive microglial staining was evident. In conclusion, neurons and astrocytes in organotypic brain slices can be labeled very fast with the fluorescent dye Mini-ruby which undergoes dynamic processes.
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Affiliation(s)
- Celine Ullrich
- Department of Psychiatry and Psychotherapy, Laboratory of Psychiatry and Exp. Alzheimers Research, Innsbruck Medical University, Anichstr 35, 6020 Innsbruck, Austria
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Foley J, Nguyen H, Bennett CB, Muschol M. Potassium accumulation as dynamic modulator of neurohypophysial excitability. Neuroscience 2010; 169:65-73. [PMID: 20433904 DOI: 10.1016/j.neuroscience.2010.04.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 04/22/2010] [Indexed: 11/28/2022]
Abstract
Activity-dependent modulation of excitable responses from neurohypophysial axons and their secretory swellings has long been recognized as an important regulator of arginine vasopressin and oxytocin release during patterned stimulation. Various activity-dependent mechanisms, including action potential broadening, potassium accumulation, and autocrine or paracrine feedback, have been proposed as underlying mechanisms. However, the relevance of any specific mechanism on net excitability in the intact preparation, during different levels of overall activation, and during realistic stimulation with trains of action potentials has remained largely undetermined. Using high-speed optical recordings and potentiometric dyes, we have quantified the dynamics of global excitability under physiologically more realistic conditions, that is in the intact neurohypophysis during trains of stimuli at varying frequencies and levels of overall activity. Net excitability facilitated during stimulation at low frequencies or at low activity. During persistent high-intensity or high-frequency stimulation, net excitability became severely depressed. Depression of excitable responses was strongly affected by manipulations of extracellular potassium levels, including changes to resting [K(+)](out), increases of interstitial spaces with hypertonic solutions and inhibition of Na(+)/K(+) ATPase activity. Application of the GABA(A) receptor blocker bicuculline or manipulations of Ca(2+) influx showed little effect. Numerical simulation of K(+) accumulation on action potentials of individual axons reproduced optically recorded population responses, including the overall depression of action potential (AP) amplitudes, modest AP broadening and the prominent loss of hyperpolarizing undershoots. Hence, extracellular potassium accumulation dominates activity-dependent depression of neurohypophysial excitability under elevated stimulation conditions. The intricate dependence on the short-term stimulation history and its resulting feedback on neurohypophysial excitability renders [K(+)](out) accumulation a surprisingly complex mechanism for regulating axonal excitability and subsequent neuroendocrine release.
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Affiliation(s)
- J Foley
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
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Kosterin P, Obaid A, Salzberg B. Long-lasting intrinsic optical changes observed in the neurointermediate lobe of the mouse pituitary reflect volume changes in cells of the pars intermedia. Neuroendocrinology 2010; 92:158-67. [PMID: 20551618 PMCID: PMC3214829 DOI: 10.1159/000314619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 03/30/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Complex intrinsic optical changes (light scattering) are readily observed in the neurointermediate lobe of the mouse pituitary gland following electrical stimulation of the infundibular stalk. Our laboratory has previously identified three distinct phases within the light scattering signal: two rapid responses to action potential stimulation and a long duration recovery. The rapid light scattering signals, restricted to the neurohypophysial portion (posterior pituitary) of the neurointermediate lobe, consist of an E-wave and an S-wave that reflect excitation and secretion, respectively. The E-wave has the approximate shape of the action potential and includes voltage- and current-related components and is independent of Ca(2+) entry. The S-wave is related to Ca(2+) entry and exocytosis. The slow recovery phase of the light scattering signal, which we designated the R-wave, is less well characterized. METHODS Using high temporal resolution light scattering measurements, we monitored intrinsic optical changes in the neurointermediate lobe of the mouse pituitary gland. Pharmacological interventions during the measurements were employed. RESULTS The data presented here provide optical and pharmacological evidence suggesting that the R-wave, which comprises signals from the posterior pituitary as well as from the pars intermedia, mirrors volume changes in pars intermedia cells following a train of stimuli applied to the infundibular stalk. These volume changes were blocked by the GABA-receptor antagonists bicuculline and picrotoxin, and were mimicked by direct application of GABA in the absence of electrical stimulation. CONCLUSIONS These results emphasize the importance of central GABAergic projections into the neurointermediate lobe, and the potential role of GABA in effecting hormone release from the pars intermedia.
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Affiliation(s)
- P. Kosterin
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pa., USA
| | - A.L. Obaid
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pa., USA
| | - B.M. Salzberg
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pa., USA
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, Pa., USA
- *Brian M. Salzberg, Department of Neuroscience, University of Pennsylvania School of Medicine, 234 Stemmler Hall, Philadelphia, PA 19104-6074 (USA), Tel. +1 215 898 2441, Fax +1 215 746 2758, E-Mail
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