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Li Y, Hu Y, Wei H, Cao W, Qi Y, Zhou S, Zhang P, Li H, Li GL, Chai R. Two-dimensional Ti 3C 2T x MXene promotes electrophysiological maturation of neural circuits. J Nanobiotechnology 2022; 20:398. [PMID: 36045382 PMCID: PMC9434915 DOI: 10.1186/s12951-022-01590-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/09/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The ideal neural interface or scaffold for stem cell therapy shall have good biocompatibility promoting survival, maturation and integration of neural stem cells (NSCs) in targeted brain regions. The unique electrical, hydrophilic and surface-modifiable properties of Ti3C2Tx MXene make it an attractive substrate, but little is known about how it interacts with NSCs during development and maturation. RESULTS In this study, we cultured NSCs on Ti3C2Tx MXene and examined its effects on morphological and electrophysiological properties of NSC-derived neurons. With a combination of immunostaining and patch-clamp recording, we found that Ti3C2Tx MXene promotes NSCs differentiation and neurite growth, increases voltage-gated current of Ca2+ but not Na+ or K+ in matured neurons, boosts their spiking without changing their passive membrane properties, and enhances synaptic transmission between them. CONCLUSIONS These results expand our understanding of interaction between Ti3C2Tx MXene and NSCs and provide a critical line of evidence for using Ti3C2Tx MXene in neural interface or scaffold in stem cell therapy.
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Affiliation(s)
- Yige Li
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yangnan Hu
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Hao Wei
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Wei Cao
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, 230069, China
| | - Yanru Qi
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Shan Zhou
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Panpan Zhang
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Huawei Li
- Department of Otorhinolaryngology and ENT Institute, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China. .,State Key Laboratory of Medical Neurobiology, and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China. .,Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China. .,NHC Key Laboratory of Hearing Medicine Fudan University, Shanghai, 200031, China. .,Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
| | - Geng-Lin Li
- Department of Otorhinolaryngology and ENT Institute, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China. .,State Key Laboratory of Medical Neurobiology, and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China. .,NHC Key Laboratory of Hearing Medicine Fudan University, Shanghai, 200031, China.
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China. .,Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China. .,Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, China. .,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China. .,Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, 100086, China. .,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, 100069, China.
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Keilhoff G, Pinkernelle J, Fansa H. The Ryanodine receptor stabilizer S107 fails to support motor neuronal neuritogenesis in vitro. Tissue Cell 2021; 73:101625. [PMID: 34419737 DOI: 10.1016/j.tice.2021.101625] [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: 06/11/2021] [Revised: 08/02/2021] [Accepted: 08/15/2021] [Indexed: 11/30/2022]
Abstract
Calcium homeostasis is essential for neuronal cell survival/differentiation. Imbalance of the Ca2+ homeostasis due to excessive Ca2+ overload is essential for spinal cord injury (SCI). The overload resulted from Ca2+ flux across the plasma membrane and from internal Ca2+ store release (mitochondria, endoplasmic reticulum, ER). Inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) are involved in releasing Ca2+ from ER contributing to axonal degeneration following SCI. In turn, block of both receptors is axoprotective. The calstabin RyR subunit, stabilizing the channel in a state of reduced activity, prevents pathological Ca2+ release too. We investigated whether S107, a RyR-stabilizing compound (Rycal), is beneficial for survival and neuritogenesis of spinal cord motor neurons in vitro. We used a spinal cord slice model and the motor neuron-like NSC-34 cell line. Effects of S107 were tested by propidium iodide/fluorescein diacetate vital staining, mitotic index determination via BrdU-incorporation, and neurite sprouting parameters. Results showed that S107 (i) had no effect on gliosis resulting from slices preparation; (ii) had no effect on motor neuronal survival and proliferation; and (iii) impaired neurite sprouting, no matter whether it was a differentiation (NSC-34 cells) or regeneration (spinal cord slices) process. The results underline the need for a flexible Ca2+homeostasis provided by the ER for re-initiation of neuritogenesis.
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Affiliation(s)
- Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, 39120, Magdeburg, Germany.
| | - Josephine Pinkernelle
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, 39120, Magdeburg, Germany
| | - Hisham Fansa
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Hand Surgery, Klinikum Bielefeld, OWL-University, 33604, Bielefeld, Germany; Department of Plastic Surgery, and Breast Centre, Spital Zollikerberg, 8125, Zollikerberg, Switzerland
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Neuritin Mediates Activity-Dependent Axonal Branch Formation in Part via FGF Signaling. J Neurosci 2016; 36:4534-48. [PMID: 27098696 DOI: 10.1523/jneurosci.1715-15.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 03/09/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Aberrant branch formation of granule cell axons (mossy fiber sprouting) is observed in the dentate gyrus of many patients with temporal lobe epilepsy and in animal models of epilepsy. However, the mechanisms underlying mossy fiber sprouting remain elusive. Based on the hypothesis that seizure-mediated gene expression induces abnormal mossy fiber growth, we screened activity-regulated genes in the hippocampus and found that neuritin, an extracellular protein anchored to the cell surface, was rapidly upregulated after electroconvulsive seizures. Overexpression of neuritin in the cultured rat granule cells promoted their axonal branching. Also, kainic acid-dependent axonal branching was abolished in the cultured granule cells fromneuritinknock-out mice, suggesting that neuritin may be involved in activity-dependent axonal branching. Moreover,neuritinknock-out mice showed less-severe seizures in chemical kindling probably by reduced mossy fiber sprouting and/or increased seizure resistance. We found that inhibition of the fibroblast growth factor (FGF) receptor attenuated the neuritin-dependent axonal branching. FGF administration also increased branching in granule neurons, whereasneuritinknock-out mice did not show FGF-dependent axonal branching. In addition, FGF and neuritin treatment enhanced the recruitment of FGF receptors to the cell surface. These findings suggest that neuritin and FGF cooperate in inducing mossy fiber sprouting through FGF signaling. Together, these results suggest that FGF and neuritin-mediated axonal branch induction are involved in the aggravation of epilepsy. SIGNIFICANCE STATEMENT This study reveals the molecular mechanism underlying mossy fiber sprouting. Mossy fiber sprouting is the aberrant axonal branching of granule neurons in the hippocampus, which is observed in patients with epilepsy. Excess amounts of neuritin, a protein upregulated by neural activity, promoted axonal branching in granule neurons. A deficiency of neuritin suppressed mossy fiber sprouting and resulted in mitigation of seizure severity. Neuritin and fibroblast growth factor (FGF) cooperated in stimulating FGF signaling and enhancing axonal branching. Neuritin is necessary for FGF-mediated recruitment of FGF receptors to the cell surface. The recruitment of FGF receptors would promote axonal branching. The discovery of this new mechanism should contribute to the development of novel antiepileptic drugs to inhibit axonal branching via neuritin-FGF signaling.
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Davidson JM, Wong CT, Rai-Bhogal R, Li H, Crawford DA. Prostaglandin E2 elevates calcium in differentiated neuroectodermal stem cells. Mol Cell Neurosci 2016; 74:71-7. [PMID: 27074429 DOI: 10.1016/j.mcn.2016.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 03/21/2016] [Accepted: 03/31/2016] [Indexed: 01/02/2023] Open
Abstract
Lipid mediator prostaglandin E2 (PGE2) is an endogenous signaling molecule that plays an important role during early development of the nervous system. Abnormalities in the PGE2 signaling pathway have been associated with neurodevelopmental disorders such as autism spectrum disorders. In this study we use ratiometric fura-2AM calcium imaging to show that higher levels of PGE2 elevate intracellular calcium levels in the cell soma and growth cones of differentiated neuroectodermal (NE-4C) stem cells. PGE2 also increased the amplitude of calcium fluctuation in the neuronal growth cones and affected the neurite extension length. In summary, our results show that PGE2 may adversely impact intracellular calcium dynamics in differentiated neuronal cells and possibly affect early development of the nervous system.
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Affiliation(s)
- Jennilee M Davidson
- Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Christine T Wong
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada
| | - Ravneet Rai-Bhogal
- Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Hongyan Li
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada
| | - Dorota A Crawford
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
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In VitroDevelopmental Neurotoxicity Following Chronic Exposure to 50 Hz Extremely Low-Frequency Electromagnetic Fields in Primary Rat Cortical Cultures. Toxicol Sci 2015; 149:433-40. [DOI: 10.1093/toxsci/kfv242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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6
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Escobedo-Avila I, Vargas-Romero F, Molina-Hernández A, López-González R, Cortés D, De Carlos JA, Velasco I. Histamine impairs midbrain dopaminergic development in vivo by activating histamine type 1 receptors. Mol Brain 2014; 7:58. [PMID: 25112718 PMCID: PMC4237960 DOI: 10.1186/s13041-014-0058-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/30/2014] [Indexed: 12/02/2022] Open
Abstract
Background Histamine (HA) regulates the sleep-wake cycle, synaptic plasticity and memory in adult mammals. Dopaminergic specification in the embryonic ventral midbrain (VM) coincides with increased HA brain levels. To study the effect of HA receptor stimulation on dopamine neuron generation, we administered HA to dopamine progenitors, both in vitro and in vivo. Results Cultured embryonic day 12 (E12) VM neural stem/progenitor cells expressed transcripts for HA receptors H1R, H2R and H3R. These undifferentiated progenitors increased intracellular calcium upon HA addition. In HA-treated cultures, dopamine neurons significantly decreased after activation of H1R. We performed intrauterine injections in the developing VM to investigate HA effects in vivo. HA administration to E12 rat embryos notably reduced VM Tyrosine Hydroxylase (TH) staining 2 days later, without affecting GABA neurons in the midbrain, or serotonin neurons in the mid-hindbrain boundary. qRT-PCR and Western blot analyses confirmed that several markers important for the generation and maintenance of dopaminergic lineage such as TH, Lmx1a and Lmx1b were significantly diminished. To identify the cell type susceptible to HA action, we injected embryos of different developmental stages, and found that neural progenitors (E10 and E12) were responsive, whereas differentiated dopaminergic neurons (E14 and E16) were not susceptible to HA actions. Proliferation was significantly diminished, whereas neuronal death was not increased in the VM after HA administration. We injected H1R or H2R antagonists to identify the receptor responsible for the detrimental effect of HA on dopaminergic lineage and found that activation of H1R was required. Conclusion These results reveal a novel action of HA affecting dopaminergic lineage during VM development.
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Affiliation(s)
| | | | | | | | | | | | - Iván Velasco
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, México D,F,-04510, Mexico.
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Calcium signaling in axon guidance. Trends Neurosci 2014; 37:424-32. [DOI: 10.1016/j.tins.2014.05.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/15/2014] [Accepted: 05/23/2014] [Indexed: 01/22/2023]
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Chiang MC, Cheng YC, Chen HM, Liang YJ, Yen CH. Rosiglitazone promotes neurite outgrowth and mitochondrial function in N2A cells via PPARgamma pathway. Mitochondrion 2014; 14:7-17. [DOI: 10.1016/j.mito.2013.12.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/09/2013] [Accepted: 12/12/2013] [Indexed: 12/21/2022]
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Electrical Stimulation Induces Calcium-Dependent Neurite Outgrowth and Immediate Early Genes Expressions of Dorsal Root Ganglion Neurons. Neurochem Res 2013; 39:129-41. [DOI: 10.1007/s11064-013-1197-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/03/2013] [Accepted: 11/07/2013] [Indexed: 10/26/2022]
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Ohashi R, Sakata SI, Naito A, Hirashima N, Tanaka M. Dendritic differentiation of cerebellar Purkinje cells is promoted by ryanodine receptors expressed by Purkinje and granule cells. Dev Neurobiol 2013; 74:467-80. [PMID: 24123915 DOI: 10.1002/dneu.22139] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 09/02/2013] [Accepted: 09/28/2013] [Indexed: 11/12/2022]
Abstract
Cerebellar Purkinje cells have the most elaborate dendritic trees among neurons in the brain. We examined the roles of ryanodine receptor (RyR), an intracellular Ca(2+) release channel, in the dendrite formation of Purkinje cells using cerebellar cell cultures. In the cerebellum, Purkinje cells express RyR1 and RyR2, whereas granule cells express RyR2. When ryanodine (10 µM), a blocker of RyR, was added to the culture medium, the elongation and branching of Purkinje cell dendrites were markedly inhibited. When we transferred small interfering RNA (siRNA) against RyR1 into Purkinje cells using single-cell electroporation, dendritic branching but not elongation of the electroporated Purkinje cells was inhibited. On the other hand, transfection of RyR2 siRNA into granule cells also inhibited dendritic branching of Purkinje cells. Furthermore, ryanodine reduced the levels of brain-derived neurotrophic factor (BDNF) in the culture medium. The ryanodine-induced inhibition of dendritic differentiation was partially rescued when BDNF was exogenously added to the culture medium in addition to ryanodine. Overall, these results suggest that RyRs expressed by both Purkinje and granule cells play important roles in promoting the dendritic differentiation of Purkinje cells and that RyR2 expressed by granule cells is involved in the secretion of BDNF from granule cells.
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Affiliation(s)
- Ryo Ohashi
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
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Lee HK, Chung SY, Na Choi SJ. MicroRNA profiling of tacrolimus-stimulated Jurkat human T lympocytes. JOURNAL OF THE KOREAN SURGICAL SOCIETY 2013; 85:161-8. [PMID: 24106682 PMCID: PMC3791358 DOI: 10.4174/jkss.2013.85.4.161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/18/2013] [Accepted: 07/24/2013] [Indexed: 11/30/2022]
Abstract
Purpose This study investigated the Jurkat T cell line expresses cytotoxicity when treated with different concentrations of FK506, and analyzed the expression pattern of microRNA when stimulated by FK506 using the microRNAs microarray, as well as the expression pattern of a gene that is related to the differentiation, activation and proliferation of T cells after being affected by the change of microRNAs. Methods To investigate the effects of FK506 on microRNA expression, we purified total RNA of Jurkat cells treated with 20 µM FK506 for 72 hours and used to analyze microRNA profiling by using Agilent's chip. Results These results demonstrated that treatment with FK506 markedly induced the down-regulation of 20 microRNAs as well as the up-regulation of 20 microRNAs in a time-dependent manner. The genes that down-regulated by FK506 include let-7a*, miR-20a*, and miR-487a. Otherwise miR-202, miR-485-5p, and miR-518c* are gradually up-regulated in expression. Sanger Institute and DAVIDs bioinformatics indicated that microRNAs regulated the several transcriptomes including nuclear factor of activated T cell-related, T cell receptor/interleukin-2 signaling, and Ca2+-calmodulin-dependent phosphatase calcineurin pathways. Conclusion As a result of treating FK506 to a Jurkat cell line and running the microRNA microarray, it was found that FK506 not only took part in the suppression of T cell proliferation/activation by inhibiting calcineurin in Jurkat apoptosis, but also affected the microRNAs that are involved in the regulation of various signal transduction pathways.
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Affiliation(s)
- Ho Kyun Lee
- Department of Surgery, Chonnam National University Medical School, Gwangju, Korea
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Zhang XF, Hyland C, Van Goor D, Forscher P. Calcineurin-dependent cofilin activation and increased retrograde actin flow drive 5-HT-dependent neurite outgrowth in Aplysia bag cell neurons. Mol Biol Cell 2012; 23:4833-48. [PMID: 23097492 PMCID: PMC3521690 DOI: 10.1091/mbc.e12-10-0715] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Neurite outgrowth in response to soluble growth factors often involves changes in intracellular Ca(2+); however, mechanistic roles for Ca(2+) in controlling the underlying dynamic cytoskeletal processes have remained enigmatic. Bag cell neurons exposed to serotonin (5-hydroxytryptamine [5-HT]) respond with a threefold increase in neurite outgrowth rates. Outgrowth depends on phospholipase C (PLC) → inositol trisphosphate → Ca(2+) → calcineurin signaling and is accompanied by increased rates of retrograde actin network flow in the growth cone P domain. Calcineurin inhibitors had no effect on Ca(2+) release or basal levels of retrograde actin flow; however, they completely suppressed 5-HT-dependent outgrowth and F-actin flow acceleration. 5-HT treatments were accompanied by calcineurin-dependent increases in cofilin activity in the growth cone P domain. 5-HT effects were mimicked by direct activation of PLC, suggesting that increased actin network treadmilling may be a widespread mechanism for promoting neurite outgrowth in response to neurotrophic factors.
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Affiliation(s)
- Xiao-Feng Zhang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
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13
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Figge C, Loers G, Schachner M, Tilling T. Neurite outgrowth triggered by the cell adhesion molecule L1 requires activation and inactivation of the cytoskeletal protein cofilin. Mol Cell Neurosci 2011; 49:196-204. [PMID: 22019611 DOI: 10.1016/j.mcn.2011.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 09/09/2011] [Accepted: 10/05/2011] [Indexed: 01/29/2023] Open
Abstract
Neurite outgrowth, an essential process for constructing nervous system connectivity, requires molecular cues which promote neurite extension and guide growing neurites. The neural cell adhesion molecule L1 is one of the molecules involved in this process. Growth of neurites depends on actin remodeling, but actin-remodeling proteins which act downstream of L1 signaling are not known. In this study, we investigated whether the actin-remodeling protein cofilin, which can be activated by dephosphorylation, is involved in neurite outgrowth stimulated by L1. Upon stimulation with an L1 monoclonal antibody which specifically triggers L1-dependent neurite outgrowth, cofilin phosphorylation in cultured cerebellar granule neurons and isolated growth cones was reduced to 47 ± 13% or 58 ± 9% of IgG control levels, respectively. We therefore investigated whether cofilin phosphorylation plays a role in L1-stimulated neurite outgrowth. Inhibition of calcineurin, a phosphatase acting upstream of cofilin dephosphorylation, impaired L1-dependent neurite extension in cultures of cerebellar granule neurons and led to an increase in cofilin phosphorylation. Moreover, when peptide S3, a competitive inhibitor of cofilin phosphorylation, or peptide pS3, a competitive inhibitor of cofilin dephosphorylation, were transferred into cerebellar neurons in culture, L1-stimulated neurite outgrowth was reduced from 173 ± 15% to 103 ± 4% of poly-L-lysine control levels in the presence of either peptide. Our findings suggest that both activation of cofilin by dephosphorylation and inactivation of cofilin by phosphorylation are essential for L1-stimulated neurite outgrowth. These results are in accordance with a cofilin activity cycle recently proposed for invasive tumor cells and inflammatory cells, indicating that a similar regulatory mechanism might be involved in neurite outgrowth. As L1 is expressed by invasive tumor cells, cofilin might also be a downstream actor of L1 in metastasis.
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Affiliation(s)
- Carina Figge
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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Sato Y, Iketani M, Kurihara Y, Yamaguchi M, Yamashita N, Nakamura F, Arie Y, Kawasaki T, Hirata T, Abe T, Kiyonari H, Strittmatter SM, Goshima Y, Takei K. Cartilage acidic protein-1B (LOTUS), an endogenous Nogo receptor antagonist for axon tract formation. Science 2011; 333:769-73. [PMID: 21817055 DOI: 10.1126/science.1204144] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Neural circuitry formation depends on the molecular control of axonal projection during development. By screening with fluorophore-assisted light inactivation in the developing mouse brain, we identified cartilage acidic protein-1B as a key molecule for lateral olfactory tract (LOT) formation and named it LOT usher substance (LOTUS). We further identified Nogo receptor-1 (NgR1) as a LOTUS-binding protein. NgR1 is a receptor of myelin-derived axon growth inhibitors, such as Nogo, which prevent neural regeneration in the adult. LOTUS suppressed Nogo-NgR1 binding and Nogo-induced growth cone collapse. A defasciculated LOT was present in lotus-deficient mice but not in mice lacking both lotus- and ngr1. These findings suggest that endogenous antagonism of NgR1 by LOTUS is crucial for normal LOT formation.
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Affiliation(s)
- Yasufumi Sato
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
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15
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Liu X, Jin Y, Liu W, Wang F, Hao S. Possible mechanism of perfluorooctane sulfonate and perfluorooctanoate on the release of calcium ion from calcium stores in primary cultures of rat hippocampal neurons. Toxicol In Vitro 2011; 25:1294-301. [PMID: 21575708 DOI: 10.1016/j.tiv.2011.04.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/12/2011] [Accepted: 04/18/2011] [Indexed: 01/17/2023]
Abstract
Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are anthropogenic compounds manufactured since the 1950s and are distributed worldwide. Now, the pollutants are being challenged by entering into the brain and the toxic effect on the central nervous system due to calcium disorder, mainly through channels on cell membrane. However, little is known about the role of calcium store in PFOS- and PFOA-evoked abnormal calcium increase. In the present study, PFOA and PFOS were measured in primary cultures of rat hippocampal neurons by LC/MS/MS analysis. Flow cytometry was used to examine altered calcium patterns in neurons labeled with fluo-3/AM and to disclose the mechanism by which PFOS and PFOA induced calcium increase in cultured neurons. The results indicate that both PFOS and PFOA can accumulate in cultured neurons and elevate calcium concentrations via release of intracellular calcium stores. Furthermore, inositol 1,4,5-trisphosphate receptors (IP(3)Rs) and ryanodine receptors (RyRs) were found to take part in PFOS or PFOA inducing calcium release from calcium stores. IP(3)Rs seem to serve a predominant role in PFOS-induced calcium release. Calcium release from intracellular stores may partially account for the perturbation of calcium homeostasis caused by PFOS or PFOA.
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Affiliation(s)
- Xiaohui Liu
- School of Environmental Science and Technology, Dalian University of Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, Dalian 116024, China
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Involvement of ryanodine receptors in neurotrophin-induced hippocampal synaptic plasticity and spatial memory formation. Proc Natl Acad Sci U S A 2011; 108:3029-34. [PMID: 21282625 DOI: 10.1073/pnas.1013580108] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ryanodine receptors (RyR) amplify activity-dependent calcium influx via calcium-induced calcium release. Calcium signals trigger postsynaptic pathways in hippocampal neurons that underlie synaptic plasticity, learning, and memory. Recent evidence supports a role of the RyR2 and RyR3 isoforms in these processes. Along with calcium signals, brain-derived neurotrophic factor (BDNF) is a key signaling molecule for hippocampal synaptic plasticity and spatial memory. Upon binding to specific TrkB receptors, BDNF initiates complex signaling pathways that modify synaptic structure and function. Here, we show that BDNF-induced remodeling of hippocampal dendritic spines required functional RyR. Additionally, incubation with BDNF enhanced the expression of RyR2, RyR3, and PKMζ, an atypical protein kinase C isoform with key roles in hippocampal memory consolidation. Consistent with their increased RyR protein content, BDNF-treated neurons generated larger RyR-mediated calcium signals than controls. Selective inhibition of RyR-mediated calcium release with inhibitory ryanodine concentrations prevented the PKMζ, RyR2, and RyR3 protein content enhancement induced by BDNF. Intrahippocampal injection of BDNF or training rats in a spatial memory task enhanced PKMζ, RyR2, RyR3, and BDNF hippocampal protein content, while injection of ryanodine at concentrations that stimulate RyR-mediated calcium release improved spatial memory learning and enhanced memory consolidation. We propose that RyR-generated calcium signals are key features of the complex neuronal plasticity processes induced by BDNF, which include increased expression of RyR2, RyR3, and PKMζ and the spine remodeling required for spatial memory formation.
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Pessah IN, Cherednichenko G, Lein PJ. Minding the calcium store: Ryanodine receptor activation as a convergent mechanism of PCB toxicity. Pharmacol Ther 2010; 125:260-85. [PMID: 19931307 PMCID: PMC2823855 DOI: 10.1016/j.pharmthera.2009.10.009] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 10/30/2009] [Indexed: 11/24/2022]
Abstract
Chronic low-level polychlorinated biphenyl (PCB) exposures remain a significant public health concern since results from epidemiological studies indicate that PCB burden is associated with immune system dysfunction, cardiovascular disease, and impairment of the developing nervous system. Of these various adverse health effects, developmental neurotoxicity has emerged as a particularly vulnerable endpoint in PCB toxicity. Arguably the most pervasive biological effects of PCBs could be mediated by their ability to alter the spatial and temporal fidelity of Ca2+ signals through one or more receptor-mediated processes. This review will focus on our current knowledge of the structure and function of ryanodine receptors (RyRs) in muscle and nerve cells and how PCBs and related non-coplanar structures alter these functions. The molecular and cellular mechanisms by which non-coplanar PCBs and related structures alter local and global Ca2+ signaling properties and the possible short and long-term consequences of these perturbations on neurodevelopment and neurodegeneration are reviewed.
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Affiliation(s)
- Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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