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Jin S, Tian S, Ding H, Yu Z, Li M. SNHG5 knockdown alleviates neuropathic pain induced by chronic constriction injury via sponging miR‑142‑5p and regulating the expression of CAMK2A. Mol Med Rep 2022; 26:221. [PMID: 35583000 PMCID: PMC9175267 DOI: 10.3892/mmr.2022.12737] [Citation(s) in RCA: 1] [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: 11/25/2020] [Accepted: 05/13/2021] [Indexed: 11/06/2022] Open
Abstract
Neuropathic pain (NP) is one of the most intractable diseases. The lack of effective therapeutic measures remains a major problem due to the poor understanding of the cause of NP. The aim of the present study was to investigate the effect of the long non‑coding RNA small nucleolar RNA host gene 5 (SNHG5) in NP and the underlying molecular mechanism in order to identify possible therapeutic targets. A chronic constriction injury (CCI) mouse model was used to investigate whether SNHG5 prevents NP and the inflammatory response. Luciferase and RNA pull‑down assays were used to detect the binding between SNHG5 and miR‑142‑5p as well as between miR‑142‑5p and CAMK2A. Western blot and qPCR were used to detect the RNA and protein expression. The results indicated that SNHG5 significantly inhibited CCI‑induced NP. In addition, SNHG5 inhibited the inflammatory response through decreasing the release and the mRNA expression of interleukin (IL)‑1β, IL‑6, IL‑10 and tumor necrosis factor‑α. Mechanistically, SNHG5 acted via sponging microRNA‑142‑5p, thereby upregulating the expression of calcium/calmodulin‑dependent protein kinase II α (CAMK2A). Further investigation indicated that CAMK2A knockdown also inhibited CCI‑induced NP and inflammation. In summary, the present study demonstrated that SNHG5 silencing could alleviate the neuropathic pain induced by chronic constriction injury via sponging miR‑142‑5p and regulating the expression of CAMK2A.
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Affiliation(s)
- Sheng Jin
- Department of Anesthesiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441021, P.R. China
| | - Shiming Tian
- Department of Anesthesiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441021, P.R. China
| | - Hanlin Ding
- Department of Anesthesiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441021, P.R. China
| | - Zhengwen Yu
- Department of Anesthesiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441021, P.R. China
| | - Mingqiang Li
- Department of Anesthesiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei 441021, P.R. China
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PKCγ promotes axonal remodeling in the cortico-spinal tract via GSK3β/β-catenin signaling after traumatic brain injury. Sci Rep 2019; 9:17078. [PMID: 31745212 PMCID: PMC6863826 DOI: 10.1038/s41598-019-53225-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/22/2019] [Indexed: 12/27/2022] Open
Abstract
Traumatic brain injury (TBI) is a common cause of death and disability. Enhancing the midline-crossing of the contralateral corticospinal tract (CST) to the denervated side of spinal cord facilitates functional recovery after TBI. Activation of the gamma isoform of PKC (PKCγ) in contralateral CST implicates its roles in promoting CST remodeling after TBI. In this study, we deployed loss and gain of function strategies in N2a cells and primary cortical neurons in vitro, and demonstrated that PKCγ is not only important but necessary for neuronal differentiation, neurite outgrowth and axonal branching but not for axonal extension. Mechanically, through the phosphorylation of GSK3β, PKCγ stabilizes the expression of cytosolic β-catenin and increase GAP43 expression, thus promoting axonal outgrowth. Further, rAAV2/9-mediated delivery of constitutive PKCγ in the corticospinal tract after unilateral TBI in vivo additionally showed that specifically delivery of active PKCγ mutant to cortical neuron promotes midline crossing of corticospinal fibers from the uninjured side to the denervated cervical spinal cord. This PKCγ-mediated injury response promoted sensorimotor functional recovery. In conclusion, PKCγ mediates stability of β-catenin through the phosphorylation of GSK3β to facilitate neuronal differentiation, neurite outgrowth and axonal branching, and PKCγ maybe a novel therapeutic target for physiological and functional recovery after TBI.
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Exploring Pharmacological Mechanisms of Xuefu Zhuyu Decoction in the Treatment of Traumatic Brain Injury via a Network Pharmacology Approach. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:8916938. [PMID: 30402137 PMCID: PMC6193325 DOI: 10.1155/2018/8916938] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/17/2018] [Indexed: 12/21/2022]
Abstract
Objectives Xuefu Zhuyu decoction (XFZYD), a traditional Chinese medicine (TCM) formula, has been demonstrated to be effective for the treatment of traumatic brain injury (TBI). However, the underlying pharmacological mechanisms remain unclear. This study aims to explore the potential action mechanisms of XFZYD in the treatment of TBI and to elucidate the combination principle of this herbal formula. Methods A network pharmacology approach including ADME (absorption, distribution, metabolism, and excretion) evaluation, target prediction, known therapeutic targets collection, network construction, and molecule docking was used in this study. Results A total of 119 bioactive ingredients from XFZYD were predicted to act on 47 TBI associated specific proteins which intervened in several crucial pathological processes including apoptosis, inflammation, antioxidant, and axon genesis. Almost each of the bioactive ingredients targeted more than one protein. The molecular docking simulation showed that 91 pairs of chemical components and candidate targets had strong binding efficiencies. The “Jun”, “Chen”, and “Zuo-Shi” herbs from XFZYD triggered their specific targets regulation, respectively. Conclusion Our work successfully illuminates the “multicompounds, multitargets” therapeutic action of XFZYD in the treatment of TBI by network pharmacology with molecule docking method. The present work may provide valuable evidence for further clinical application of XFZYD as therapeutic strategy for TBI treatment.
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White SH, Sturgeon RM, Gu Y, Nensi A, Magoski NS. Tyrosine Phosphorylation Determines Afterdischarge Initiation by Regulating an Ionotropic Cholinergic Receptor. Neuroscience 2018; 372:273-288. [PMID: 29306054 DOI: 10.1016/j.neuroscience.2017.12.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/30/2017] [Accepted: 12/26/2017] [Indexed: 12/12/2022]
Abstract
Changes to neuronal activity often involve a rapid and precise transition from low to high excitability. In the marine snail, Aplysia, the bag cell neurons control reproduction by undergoing an afterdischarge, which begins with synaptic input releasing acetylcholine to open an ionotropic cholinergic receptor. Gating of this receptor causes depolarization and a shift from silence to continuous action potential firing, leading to the neuroendocrine secretion of egg-laying hormone and ovulation. At the onset of the afterdischarge, there is a rise in intracellular Ca2+, followed by both protein kinase C (PKC) activation and tyrosine dephosphorylation. To determine whether these signals influence the acetylcholine ionotropic receptor, we examined the bag cell neuron cholinergic response both in culture and isolated clusters using whole-cell and/or sharp-electrode electrophysiology. The acetylcholine-induced current was not altered by increasing intracellular Ca2+ via voltage-gated Ca2+ channels, clamping intracellular Ca2+ with exogenous Ca2+ buffers, or activating PKC with phorbol esters. However, lowering phosphotyrosine levels by inhibiting tyrosine kinases both reduced the cholinergic current and prevented acetylcholine from triggering action potentials or afterdischarge-like bursts. In other systems, acetylcholine receptors are often modulated by multiple signals, but bag cell neurons appear to be more restrictive in this regard. Prior work finds that, as the afterdischarge proceeds, tyrosine dephosphorylation leads to biophysical alterations that promote persistent firing. Because this firing is subsequent to the cholinergic input, inhibiting the acetylcholine receptor may represent a means of properly orchestrating synaptically induced changes in excitability.
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Affiliation(s)
- Sean H White
- Department of Biomedical and Molecular Sciences, Physiology and Neuroscience Graduate Programs, Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Raymond M Sturgeon
- Department of Biomedical and Molecular Sciences, Physiology and Neuroscience Graduate Programs, Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Yueling Gu
- Department of Biomedical and Molecular Sciences, Physiology and Neuroscience Graduate Programs, Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Alysha Nensi
- Department of Biomedical and Molecular Sciences, Physiology and Neuroscience Graduate Programs, Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Neil S Magoski
- Department of Biomedical and Molecular Sciences, Physiology and Neuroscience Graduate Programs, Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
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5
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Role of nociceptor αCaMKII in transition from acute to chronic pain (hyperalgesic priming) in male and female rats. J Neurosci 2013; 33:11002-11. [PMID: 23825405 DOI: 10.1523/jneurosci.1785-13.2013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have previously shown that activation of protein kinase Cε (PKCε) in male rats induces a chronic, long-lasting change in nociceptors such that a subsequent exposure to proinflammatory mediators produces markedly prolonged mechanical hyperalgesia. This neuroplastic change, hyperalgesic priming, is dependent on activation of cytoplasmic polyadenylation element-binding protein (CPEB), downstream of PKCε, and consequent translation of mRNAs in the peripheral terminal of the nociceptor. Since α calmodulin-dependent protein kinase II (αCaMKII), a molecule implicated in neuroplasticity, is a target of CPEB and can also affect CPEB function, we investigated its role in the transition from acute to chronic pain. Priming induced by direct activation of PKCε can be prevented by inhibition of αCaMKII. In addition, direct activation of αCaMKII induces priming, which was not prevented by pretreatment with PKCε antisense, suggesting that αCaMKII is downstream of PKCε in the induction of priming. Activation of ryanodine receptors (RyRs), which can lead to activation of αCaMKII, also induced priming, in a calcium- and αCaMKII-dependent manner. Similarly, inhibition of the RyR and a calcium buffer prevented induction of priming by PKCε. Unlike activation of PKCε, ryanodine and αCaMKII induced priming in female as well as male rats. Our results demonstrate a contribution of αCaMKII to induction of hyperalgesic priming, a phenomenon implicated in the transition from acute to chronic pain.
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Franco CF, Soares R, Pires E, Santos R, Coelho AV. Radial nerve cord protein phosphorylation dynamics during starfish arm tip wound healing events. Electrophoresis 2012; 33:3764-78. [DOI: 10.1002/elps.201200274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/05/2012] [Accepted: 07/14/2012] [Indexed: 01/14/2023]
Affiliation(s)
- Catarina F. Franco
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras; Portugal
| | - Renata Soares
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras; Portugal
| | - Elisabete Pires
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras; Portugal
| | | | - Ana V. Coelho
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras; Portugal
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Chen L, Chisholm AD. Axon regeneration mechanisms: insights from C. elegans. Trends Cell Biol 2011; 21:577-84. [PMID: 21907582 DOI: 10.1016/j.tcb.2011.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 11/28/2022]
Abstract
Understanding the mechanisms of axon regeneration is of great importance to the development of therapeutic treatments for spinal cord injury or stroke. Axon regeneration has long been studied in diverse vertebrate and invertebrate models, but until recently had not been analyzed in the genetically tractable model organism Caenorhabditis elegans. The small size, simple neuroanatomy, and transparency of C. elegans allows single fluorescently labeled axons to be severed in live animals using laser microsurgery. Many neurons in C. elegans are capable of regenerative regrowth, and can in some cases re-establish functional connections. Large-scale genetic screens have begun to elucidate the genetic basis of axon regrowth.
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Affiliation(s)
- Lizhen Chen
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Shim S, Ming GL. Roles of channels and receptors in the growth cone during PNS axonal regeneration. Exp Neurol 2009; 223:38-44. [PMID: 19833126 DOI: 10.1016/j.expneurol.2009.10.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 10/01/2009] [Accepted: 10/03/2009] [Indexed: 12/18/2022]
Abstract
Neurons in the peripheral nervous system (PNS) are known to maintain a regenerative capacity and will normally regenerate their axons within a permissive growth environment. The success of regeneration in the PNS largely depends on maintenance of the supportive basal lamina membrane, efficient removal of axonal and myelin debris by macrophages and Schwann cells, expression of neurotrophic factors by Schwann cells, and up-regulation of the intrinsic growth program in PNS neurons. The PNS regenerative process is well characterized through initial Wallerian degeneration followed by axonal sprouting, formation of neuronal growth cones, active axonal growth to the target, and finally sensory and motor functional recovery. The initiation and maintenance of active growth cones during peripheral nerve regeneration recapitulate many aspects of early neural development and are achieved through the activation of complex signaling cascades, involving various receptors, channels, cytoplasmic signaling cascades, as well as transcriptional and translational programs. This review focuses on roles of cell surface ion channels and receptors in the growth cone during Wallerian degeneration and axon regeneration in the PNS.
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Affiliation(s)
- Sangwoo Shim
- Institute for Cell Engineering, Department of Neurology, Johns Hopkins University School of Medicine, 733 N. Broadway, BRB 779, Baltimore, MD 21205, USA
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Kamber D, Erez H, Spira ME. Local calcium-dependent mechanisms determine whether a cut axonal end assembles a retarded endbulb or competent growth cone. Exp Neurol 2009; 219:112-25. [DOI: 10.1016/j.expneurol.2009.05.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 05/03/2009] [Accepted: 05/05/2009] [Indexed: 12/19/2022]
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Xu JJ, Chen EY, Lu CL, He C. Recombinant ciliary neurotrophic factor promotes nerve regeneration and induces gene expression in silicon tube-bridged transected sciatic nerves in adult rats. J Clin Neurosci 2009; 16:812-7. [PMID: 19289286 DOI: 10.1016/j.jocn.2008.08.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2008] [Revised: 08/19/2008] [Accepted: 08/24/2008] [Indexed: 10/21/2022]
Abstract
Sciatic nerves in adult male rats were transected and reunited via a silicone chamber. This was followed by a focal injection of recombinant ciliary neurotrophic factor (CNTF). To evaluate the effect of this therapeutic approach and to explore its possible mechanisms, nerve regeneration was traced by horseradish peroxidase retrograde labeling. Functional recovery was evaluated by functional assessment of the hind feet and the expression of a number of proteins was detected using immunohistochemistry. The results showed that a single administration of CNTF could promote regeneration of motor axons, with improved functional recovery in adult rats. Growth associated protein (GAP)-43, S100, CD68 and major histocompatibility complex class II immunoreactivity in the regenerative and distal nerves suggested that CNTF could promote axon regeneration, Schwann cell migration, monocyte infiltration and activation. CNTF might also indirectly promote axonal regeneration by further activating the JAK-STAT3 pathway and subsequently upregulating phosphotyrosine, GAP-43 and S100 expression to enhance proliferation, growth and migration of Schwann cells. CNTF has suggested important targets for pharmacological intervention in peripheral nerve disease and injury.
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Affiliation(s)
- Jia-jun Xu
- Department of Anatomy, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
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11
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Hultman K, Tjärnlund-Wolf A, Fish RJ, Wilhelmsson U, Rydenhag B, Pekny M, Kruithof EKO, Jern C. Retinoids and activation of PKC induce tissue-type plasminogen activator expression and storage in human astrocytes. J Thromb Haemost 2008; 6:1796-803. [PMID: 18647223 DOI: 10.1111/j.1538-7836.2008.03084.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Emerging data demonstrate important roles for tissue-type plasminogen activator (t-PA) in the central nervous system (CNS). In contrast to endothelial cells, little is known about the regulation of t-PA gene expression and secretion in astrocytes. OBJECTIVES The aims of the present study were to investigate whether t-PA gene expression is regulated by retinoids and the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) in human astrocytes, and to study whether t-PA is stored and subject to regulated release from these cells, as with endothelial cells. METHODS Native human astrocytes were treated with RA and/or PMA. mRNA was quantified by real-time RT-PCR and protein secretion determined by ELISA. Intracellular t-PA immunoreactivity in astrocytes was examined by immunocyto- and histochemistry. RESULTS RA and/or PMA induced a time-dependent increase in t-PA mRNA and protein levels in astrocytes, reaching 10-fold after combined treatment. This was associated with increased amounts of t-PA storage in intracellular granular structures. Both forskolin and histamine induced regulated release of t-PA. The presence of t-PA in reactive astrocytes was confirmed in human brain tissue. CONCLUSIONS These data show that RA and PKC activation induce a strong up-regulation of t-PA expression in astrocytes, and increased intracellular storage pools. Moreover, a regulated release of t-PA can be induced from these cells. This raises the possibility that astrocytes contribute to the regulation of extracellular t-PA levels in the CNS.
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Affiliation(s)
- K Hultman
- Institute of Neuroscience and Physiology, Department of Clinical Neuroscience and Rehabilitation, the Sahlgrenska Academy at University of Gothenburg, Department of Clinical Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden
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Canan S, Aktaş A, Ulkay MB, Colakoglu S, Ragbetli MC, Ayyildiz M, Geuna S, Kaplan S. Prenatal exposure to a non‐steroidal anti‐inflammatory drug or saline solution impairs sciatic nerve morphology: a stereological and histological study. Int J Dev Neurosci 2008; 26:733-8. [DOI: 10.1016/j.ijdevneu.2008.07.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/27/2008] [Accepted: 07/06/2008] [Indexed: 11/24/2022] Open
Affiliation(s)
- Sinan Canan
- Department of PhysiologyBaskent University School of MedicineTR‐06530AnkaraTurkey
| | - Abit Aktaş
- Department of Histology and EmbryologyIstanbul University School of Veterinary MedicineTR‐34320IstanbulTurkey
| | - M. Basak Ulkay
- Department of Histology and EmbryologyIstanbul University School of Veterinary MedicineTR‐34320IstanbulTurkey
| | - Serdar Colakoglu
- Department of AnatomyDuzce University School of MedicineDuzceTurkey
| | - Murat Cetin Ragbetli
- Department of Histology and EmbryologyYüzüncü Yıl University School of MedicineVanTurkey
| | - Mustafa Ayyildiz
- Department of PhysiologyOndokuz Mayis University School of MedicineSamsunTurkey
| | - Stefano Geuna
- Dipartimento Di Scienze Cliniche E BiologicheUniversity Torino Ospedale San LuigiRegione Gonzole10‐10043OrbassanoTorinoItaly
| | - Suleyman Kaplan
- Department of Histology and EmbryologyOndokuz Mayis University School of MedicineTR‐55139SamsunTurkey
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Verbeek DS, Goedhart J, Bruinsma L, Sinke RJ, Reits EA. PKC gamma mutations in spinocerebellar ataxia type 14 affect C1 domain accessibility and kinase activity leading to aberrant MAPK signaling. J Cell Sci 2008; 121:2339-49. [PMID: 18577575 DOI: 10.1242/jcs.027698] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Spinocerebellar ataxia type 14 (SCA14) is a neurodegenerative disorder caused by mutations in the neuronal-specific protein kinase C gamma (PKCgamma) gene. Since most mutations causing SCA14 are located in the PKCgamma C1B regulatory subdomain, we investigated the impact of three C1B mutations on the intracellular kinetics, protein conformation and kinase activity of PKCgamma in living cells. SCA14 mutant PKCgamma proteins showed enhanced phorbol-ester-induced kinetics when compared with wild-type PKCgamma. The mutations led to a decrease in intramolecular FRET of PKCgamma, suggesting that they ;open' PKCgamma protein conformation leading to unmasking of the phorbol ester binding site in the C1 domain. Surprisingly, SCA14 mutant PKCgamma showed reduced kinase activity as measured by phosphorylation of PKC reporter MyrPalm-CKAR, as well as downstream components of the MAPK signaling pathway. Together, these results show that SCA14 mutations located in the C1B subdomain ;open' PKCgamma protein conformation leading to increased C1 domain accessibility, but inefficient activation of downstream signaling pathways.
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Affiliation(s)
- Dineke S Verbeek
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, AZ Amsterdam, The Netherlands.
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Cnops L, Hu TT, Eysel UT, Arckens L. Effect of binocular retinal lesions on CRMP2 and CRMP4 but not Dyn I and Syt I expression in adult cat area 17. Eur J Neurosci 2007; 25:1395-401. [PMID: 17425566 DOI: 10.1111/j.1460-9568.2007.05395.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Removal of retinal input from a restricted region of adult cat visual cortex leads to a substantial reorganization of the retinotopy within the sensory-deprived cortical lesion projection zone (LPZ). Still little is known about the molecular mechanisms underlying this cortical map reorganization. We chose two members of the collapsin response mediator protein (CRMP) family, CRMP2 and CRMP4, because of their involvement in neurite growth, and compared gene and protein expression levels between normal control and reorganizing visual cortex upon induction of central retinal lesions. Parallel analysis of Dynamin I (Dyn I) and Synaptotagmin I (Syt I), two molecules implicated in the exocytosis-endocytosis cycle, was performed because changes in neurotransmitter release have been implicated in cortical plasticity. Western blotting and real-time polymerase chain reaction revealed a clear time-dependent effect of retinal lesioning on CRMP2 and CRMP4 expression, with maximal impact 2 weeks post-lesion. Altered CRMP levels were not a direct consequence of decreased visual activity in the LPZ as complete surgical removal of retinal input to one hemisphere had no effect on CRMP2 or CRMP4 expression. Thus, CRMP expression is correlated to cortical reorganization following partial deafferentation of adult visual cortex. In contrast, Dyn I and Syt I were not influenced and thereby do not promote exocytosis-endocytosis cycle modifications in adult cat cortical plasticity.
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Affiliation(s)
- Lieselotte Cnops
- Laboratory of Neuroplasticity and Neuroproteomics, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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15
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Abstract
Neuronal motility is a fundamental feature that underlies the development, regeneration, and plasticity of the nervous system. Two major developmental events--directed migration of neuronal precursor cells to the proper positions and guided elongation of axons to their target cells--depend on large-scale neuronal motility. At a finer scale, motility is also manifested in many aspects of neuronal structures and functions, ranging from differentiation and refinement of axonal and dendritic morphology during development to synapse remodeling associated with learning and memory in the adult brain. As a primary second messenger that conveys the cytoplasmic actions of electrical activity and many neuroactive ligands, Ca(2+) plays a central role in the regulation of neuronal motility. Recent studies have revealed common Ca(2+)-dependent signaling pathways that are deployed for regulating cytoskeletal dynamics associated with neuronal migration, axon and dendrite development and regeneration, and synaptic plasticity.
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Affiliation(s)
- James Q Zheng
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
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Abstract
Failure of severed adult CNS axons to regenerate could be attributed to both a reduced intrinsic capacity to grow and an heightened susceptibility to inhibitory factors of the CNS extracellular environment. A particularly interesting and useful paradigm for investigating CNS axonal regeneration is its enhancement at the CNS branch of dorsal root ganglion (DRG) neurons after conditional lesioning of their peripheral branch. Recent reports have implicated the involvement of two well-known signaling pathways utilizing separate transcription factors; the Cyclic AMP (cAMP) response element binding protein (CREB) and signal transducer and activator of transcription 3 (STAT3), in conditional lesioning. The former appears to be the pathway activated by neurotrophic factors and Bcl-2, while the latter is responsible for the neurogenic effect of cytokines [such as the leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) elevated at lesion sites]. Recent findings also augmented earlier notions that modulations of the activity of another class of cellular signaling intermediate, the conventional protein kinase C (PKC), could result in a contrasting growth response by CNS neurons to myelin-associated inhibitors. We discuss these signaling pathways and mechanisms, in conjunction with other recent reports of regeneration enhancement and also within the context of what is known about aiding regeneration of injured CNS axons.
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Affiliation(s)
- Felicia Yu Hsuan Teng
- Department of Biochemistry Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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Lallemend F, Hadjab S, Hans G, Moonen G, Lefebvre PP, Malgrange B. Activation of protein kinase CbetaI constitutes a new neurotrophic pathway for deafferented spiral ganglion neurons. J Cell Sci 2006; 118:4511-25. [PMID: 16179609 DOI: 10.1242/jcs.02572] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In mammals, degeneration of peripheral auditory neurons constitutes one of the main causes of sensorineural hearing loss. Unfortunately, to date, pharmacological interventions aimed at counteracting this condition have not presented complete effectiveness in protecting the integrity of cochlear neural elements. In this context, the protein kinase C (PKC) family of enzymes are important signalling molecules that play a role in preventing neurodegeneration after nervous system injury. The present study demonstrates, for the first time, that the PKC signalling pathway is directly neurotrophic to axotomised spiral ganglion neurons (SGNs). We found that PKCbetaI was strictly expressed by postnatal and adult SGNs both in situ and in vitro. In cultures of SGNs, we observed that activators of PKC, such as phorbol esters and bryostatin 1, induced neuronal survival and neurite regrowth in a manner dependent on the activation of PKCbetaI. The neuroprotective effects of PKC activators were suppressed by pre-treatment with LY294002 (a PI3K inhibitor) and with U0126 (a MEK inhibitor), indicating that PKC activators promote the survival and neurite outgrowth of SGNs by both PI3K/Akt and MEK/ERK-dependent mechanisms. In addition, whereas combining the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) was shown to provide only an additive effect on SGN survival, the interaction between PKC and neurotrophin signalling gave rise to a synergistic increase in SGN survival. Taken together, the data indicate that PKCbetaI activation represents a key factor for the protection of the integrity of neural elements in the cochlea.
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Affiliation(s)
- François Lallemend
- Research Centre for Cellular and Molecular Neurobiology, Developmental Neurobiology Unit, University of Liège, Av. de l'Hopital 1 B36, 4000 Liège, Belgium.
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Craske ML, Fivaz M, Batada NN, Meyer T. Spines and neurite branches function as geometric attractors that enhance protein kinase C action. ACTA ACUST UNITED AC 2005; 170:1147-58. [PMID: 16186260 PMCID: PMC2171530 DOI: 10.1083/jcb.200503118] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca2+ and diacylglycerol-regulated protein kinase Cs (PKCs; conventional PKC isoforms, such as PKCγ) are multifunctional signaling molecules that undergo reversible plasma membrane translocation as part of their mechanism of activation. In this article, we investigate PKCγ translocation in hippocampal neurons and show that electrical or glutamate stimulation leads to a striking enrichment of PKCγ in synaptic spines and dendritic branches. Translocation into spines and branches was delayed when compared with the soma plasma membrane, and PKCγ remained in these structures for a prolonged period after the response in the soma ceased. We have developed a quantitative model for the translocation process by measuring the rate at which PKCγ crossed the neck of spines, as well as cytosolic and membrane diffusion coefficients of PKCγ. Our study suggests that neurons make use of a high surface-to-volume ratio of spines and branches to create a geometric attraction process for PKC that imposes a delayed enhancement of PKC action at synapses and in peripheral processes.
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Affiliation(s)
- Madeleine L Craske
- Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Chierzi S, Ratto GM, Verma P, Fawcett JW. The ability of axons to regenerate their growth cones depends on axonal type and age, and is regulated by calcium, cAMP and ERK. Eur J Neurosci 2005; 21:2051-62. [PMID: 15869501 DOI: 10.1111/j.1460-9568.2005.04066.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The processes activated at the time of axotomy and leading to the formation of a new growth cone are the first step in regeneration, but are still poorly characterized. We investigated this event in an in vitro model of axotomy performed on dorsal root ganglia and retinal explants. We observed that the dorsal root ganglion axons and retinal ganglion cell axons, which had grown out on a poly d-lysine/laminin substrate at the time of culture preparation greatly differed in their regenerative response after a subsequent in vitro lesion made far from the cell body. The majority of axons of adult dorsal root ganglia but only a small percentage of axons of adult retinal ganglion cells regenerated new growth cones within four hours after in vitro axotomy, though both kinds of axons were growing before the lesion. The depletion of extracellular calcium and the inhibition of extracellular-signal regulated kinase 1,2 (ERK) and protein kinase A (PKA) at the time of injury significantly impaired the capacity of dorsal root ganglia axons to re-initiate growth cones without affecting growth cone motility. Pharmacological treatments directed at increasing the level of cAMP promoted growth cone regeneration in adult retinal ganglion cell axons in spite of the low regenerative potential exhibited in normal conditions. Understanding the cellular mechanisms activated at the time of lesion and leading to the formation of a new growth cone is necessary for devising treatments aimed at enhancing the regenerative response of injured axons.
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Affiliation(s)
- Sabrina Chierzi
- Cambridge University Centre for Brain Repair, Robinson Way, Cambridge CB2 2PY, UK.
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Falluel-Morel A, Vaudry D, Aubert N, Galas L, Benard M, Basille M, Fontaine M, Fournier A, Vaudry H, Gonzalez BJ. Pituitary adenylate cyclase-activating polypeptide prevents the effects of ceramides on migration, neurite outgrowth, and cytoskeleton remodeling. Proc Natl Acad Sci U S A 2005; 102:2637-42. [PMID: 15695581 PMCID: PMC549011 DOI: 10.1073/pnas.0409681102] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Indexed: 01/29/2023] Open
Abstract
During neuronal migration, cells that do not reach their normal destination or fail to establish proper connections are eliminated through an apoptotic process. Recent studies have shown that the proinflammatory cytokine tumor necrosis factor alpha (and its second messengers ceramides) and the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) play a pivotal role in the histogenesis of the cerebellar cortex. However, the effects of ceramides and PACAP on migration of cerebellar granule cells have never been investigated. Time-lapse videomicroscopy recording showed that C2-ceramide, a cell-permeable ceramide analog, and PACAP induced opposite effects on cell motility and neurite outgrowth. C2-ceramide markedly stimulated cell movements during the first hours of treatment and inhibited neuritogenesis, whereas PACAP reduced cell migration and promoted neurite outgrowth. These actions of C2-ceramide on cell motility and neurite outgrowth were accompanied by a disorganization of the actin filament network, depolarization of tubulin, and alteration of the microtubule-associated protein Tau. In contrast, PACAP strengthened the polarization of actin at the emergence cone, increased Tau phosphorylation, and abolished C2-ceramide-evoked alterations of the cytoskeletal architecture. The caspase-inhibitor Z-VAD-FMK, like PACAP, suppressed the "dance of the death" provoked by C2-ceramide. Finally, Z-VAD-FMK and the PP2A inhibitor okadaic acid both prevented the impairment of Tau phosphorylation induced by C2-ceramide. Taken together, these data indicate that the reverse actions of C2-ceramide and PACAP on cerebellar granule cell motility and neurite outgrowth are attributable to their opposite effects on actin distribution, tubulin polymerization, and Tau phosphorylation.
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Affiliation(s)
- Anthony Falluel-Morel
- European Institute for Peptide Research (Institut Fédératif de Recherches Multidisciplinares sur les Peptides 23), Institut National de la Santé et de la Recherche Médicale U413, University of Rouen, 76821 Mont-Saint-Aignan, France
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