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Saloman JL, Epouhe AY, Ruff CF, Albers KM. PDX1, a transcription factor essential for organ differentiation, regulates SERCA-dependent Ca 2+ homeostasis in sensory neurons. Cell Calcium 2024; 120:102884. [PMID: 38574509 PMCID: PMC11188734 DOI: 10.1016/j.ceca.2024.102884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/13/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
Pancreatic and duodenal homeobox 1 (PDX1) is a transcription factor required for the development and differentiation of the pancreas. Previous studies indicated that PDX1 expression was restricted to the gastrointestinal tract. Using a cre-dependent reporter, we observed PDX1-dependent expression of tdtomato (PDX1-tom) in a subpopulation of sensory nerves. Many of these PDX1-tom afferents expressed the neurofilament 200 protein and projected to the skin. Tdtomato-labeled terminals were associated with hair follicles in the form of longitudinal and circumferential lanceolate endings suggesting a role in tactile and proprioceptive perception. To begin to examine the functional significance of PDX1 in afferents, we used Fura-2 imaging to examine calcium (Ca2+) handling under naïve and nerve injury conditions. Neuropathic injury is associated with increased intracellular Ca2+ signaling that in part results from dysregulation of the sarco/endoplasmic reticulum calcium transport ATPase (SERCA). Here we demonstrate that under naïve conditions, PDX1 regulates expression of the SERCA2B isoform in sensory neurons. In response to infraorbital nerve injury, a significant reduction of PDX1 and SERCA2B expression and dysregulation of Ca2+ handling occurs in PDX1-tom trigeminal ganglia neurons. The identification of PDX1 expression in the somatosensory system and its regulation of SERCA2B and Ca2+ handling provide a new mechanism to explain pathological changes in primary afferents that may contribute to pain associated with nerve injury.
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Affiliation(s)
- Jami L Saloman
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Ariel Y Epouhe
- Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Catherine F Ruff
- Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kathryn M Albers
- Department of Neurobiology, Center for Neuroscience and Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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2
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Varlamova EG, Baryshev AS, Gudkov SV, Babenko VA, Plotnikov EY, Turovsky EA. Cerium Oxide Nanoparticles Protect Cortical Astrocytes from Oxygen-Glucose Deprivation through Activation of the Ca 2+ Signaling System. Int J Mol Sci 2023; 24:14305. [PMID: 37762608 PMCID: PMC10531718 DOI: 10.3390/ijms241814305] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Most of the works aimed at studying the cytoprotective properties of nanocerium are usually focused on the mechanisms of regulation of the redox status in cells while the complex effects of nanocerium on calcium homeostasis, the expression of pro-apoptotic and protective proteins are generally overlooked. There is a problem of a strong dependence of the effects of cerium oxide nanoparticles on their size, method of preparation and origin, which significantly limits their use in medicine. In this study, using the methods of molecular biology, immunocytochemistry, fluorescence microscopy and inhibitory analysis, the cytoprotective effect of cerium oxide nanoparticles obtained by laser ablation on cultured astrocytes of the cerebral cortex under oxygen-glucose deprivation (OGD) and reoxygenation (ischemia-like conditions) are shown. The concentration effects of cerium oxide nanoparticles on ROS production by astrocytes in an acute experiment and the effects of cell pre-incubation with nanocerium on ROS production under OGD conditions were studied. The dose dependence for nanocerium protection of cortical astrocytes from a global increase in calcium ions during oxygen-glucose deprivation and cell death were demonstrated. The concentration range of cerium oxide nanoparticles at which they have a pro-oxidant effect on cells has been identified. The effect of nanocerium concentrations on astrocyte preconditioning, accompanied by increased expression of protective proteins and limited ROS production induced by oxygen-glucose deprivation, has been investigated. In particular, a correlation was found between an increase in the concentration of cytosolic calcium under the action of nanocerium and the suppression of cell death. As a result, the positive and negative effects of nanocerium under oxygen-glucose deprivation and reoxygenation in astrocytes were revealed at the molecular level. Nanocerium was found to act as a "double-edged sword" and to have a strictly defined concentration therapeutic "window".
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Affiliation(s)
- Elena G. Varlamova
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia
| | - Alexey S. Baryshev
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilove St., 119991 Moscow, Russia
| | - Sergey V. Gudkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilove St., 119991 Moscow, Russia
| | - Valentina A. Babenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Egor A. Turovsky
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia
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3
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Carlton AJ, Jeng J, Grandi FC, De Faveri F, Ceriani F, De Tomasi L, Underhill A, Johnson SL, Legan KP, Kros CJ, Richardson GP, Mustapha M, Marcotti W. A critical period of prehearing spontaneous Ca 2+ spiking is required for hair-bundle maintenance in inner hair cells. EMBO J 2023; 42:e112118. [PMID: 36594367 PMCID: PMC9929643 DOI: 10.15252/embj.2022112118] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 01/04/2023] Open
Abstract
Sensory-independent Ca2+ spiking regulates the development of mammalian sensory systems. In the immature cochlea, inner hair cells (IHCs) fire spontaneous Ca2+ action potentials (APs) that are generated either intrinsically or by intercellular Ca2+ waves in the nonsensory cells. The extent to which either or both of these Ca2+ signalling mechansims are required for IHC maturation is unknown. We find that intrinsic Ca2+ APs in IHCs, but not those elicited by Ca2+ waves, regulate the maturation and maintenance of the stereociliary hair bundles. Using a mouse model in which the potassium channel Kir2.1 is reversibly overexpressed in IHCs (Kir2.1-OE), we find that IHC membrane hyperpolarization prevents IHCs from generating intrinsic Ca2+ APs but not APs induced by Ca2+ waves. Absence of intrinsic Ca2+ APs leads to the loss of mechanoelectrical transduction in IHCs prior to hearing onset due to progressive loss or fusion of stereocilia. RNA-sequencing data show that pathways involved in morphogenesis, actin filament-based processes, and Rho-GTPase signaling are upregulated in Kir2.1-OE mice. By manipulating in vivo expression of Kir2.1 channels, we identify a "critical time period" during which intrinsic Ca2+ APs in IHCs regulate hair-bundle function.
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Affiliation(s)
| | - Jing‐Yi Jeng
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | | | | | | | | | | | - Stuart L Johnson
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Kevin P Legan
- School of Life SciencesUniversity of Sussex, FalmerBrightonUK
| | - Corné J Kros
- School of Life SciencesUniversity of Sussex, FalmerBrightonUK
| | | | - Mirna Mustapha
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Walter Marcotti
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
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4
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Hartung JE, Moy JK, Loeza-Alcocer E, Nagarajan V, Jostock R, Christoph T, Schroeder W, Gold MS. Voltage-gated calcium currents in human dorsal root ganglion neurons. Pain 2022; 163:e774-e785. [PMID: 34510139 PMCID: PMC8882208 DOI: 10.1097/j.pain.0000000000002465] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/10/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Voltage-gated calcium channels in sensory neurons underlie processes ranging from neurotransmitter release to gene expression and remain a therapeutic target for the treatment of pain. Yet virtually all we know about voltage-gated calcium channels has been obtained through the study of rodent sensory neurons and heterologously expressed channels. To address this, high voltage-activated (HVA) Ca2+ currents in dissociated human and rat dorsal root ganglion neurons were characterized with whole-cell patch clamp techniques. The HVA currents from both species shared basic biophysical and pharmacological properties. However, HVA currents in human neurons differed from those in the rat in at least 3 potentially important ways: (1) Ca2+ current density was significantly smaller, (2) the proportion of nifedipine-sensitive currents was far greater, and (3) a subpopulation of human neurons displayed relatively large constitutive current inhibition. These results highlight the need to for the study of native proteins in their native environment before initiating costly clinical trials.
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Affiliation(s)
- Jane E Hartung
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
| | - Jamie K Moy
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
| | | | - Vidhya Nagarajan
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
| | | | | | | | - Michael S Gold
- University of Pittsburgh School of Medicine, Department of Neurobiology, PA, USA
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5
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Enander JMD, Loeb GE, Jorntell H. A Model for Self-Organization of Sensorimotor Function: Spinal Interneuronal Integration. J Neurophysiol 2022; 127:1478-1495. [PMID: 35475709 PMCID: PMC9293245 DOI: 10.1152/jn.00054.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Control of musculoskeletal systems depends on integration of voluntary commands and somatosensory feedback in the complex neural circuits of the spinal cord. Particular connectivity patterns have been identified experimentally, and it has been suggested that these may result from the wide variety of transcriptional types that have been observed in spinal interneurons. We ask instead whether the details of these connectivity patterns (and perhaps many others) can arise as a consequence of Hebbian adaptation during early development. We constructed an anatomically simplified model plant system with realistic muscles and sensors and connected it to a recurrent, random neuronal network consisting of both excitatory and inhibitory neurons endowed with Hebbian learning rules. We then generated a wide set of randomized muscle twitches typical of those described during fetal development and allowed the network to learn. Multiple simulations consistently resulted in diverse and stable patterns of activity and connectivity that included subsets of the interneurons that were similar to 'archetypical' interneurons described in the literature. We also found that such learning led to an increased degree of cooperativity between interneurons when performing larger limb movements on which it had not been trained. Hebbian learning gives rise to rich sets of diverse interneurons whose connectivity reflects the mechanical properties of the plant. At least some of the transcriptomic diversity may reflect the effects of this process rather than the cause of the connectivity. Such a learning process seems better suited to respond to the musculoskeletal mutations that underlie the evolution of new species.
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Affiliation(s)
- Jonas M D Enander
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
| | - Gerald E Loeb
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
| | - Henrik Jorntell
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden
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6
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Hogan MK, Hamilton GF, Horner PJ. Neural Stimulation and Molecular Mechanisms of Plasticity and Regeneration: A Review. Front Cell Neurosci 2020; 14:271. [PMID: 33173465 PMCID: PMC7591397 DOI: 10.3389/fncel.2020.00271] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/31/2020] [Indexed: 12/23/2022] Open
Abstract
Neural stimulation modulates the depolarization of neurons, thereby triggering activity-associated mechanisms of neuronal plasticity. Activity-associated mechanisms in turn play a major role in post-mitotic structure and function of adult neurons. Our understanding of the interactions between neuronal behavior, patterns of neural activity, and the surrounding environment is evolving at a rapid pace. Brain derived neurotrophic factor is a critical mediator of activity-associated plasticity, while multiple immediate early genes mediate plasticity of neurons following bouts of neural activity. New research has uncovered genetic mechanisms that govern the expression of DNA following changes in neural activity patterns, including RNAPII pause-release and activity-associated double stranded breaks. Discovery of novel mechanisms governing activity-associated plasticity of neurons hints at a layered and complex molecular control of neuronal response to depolarization. Importantly, patterns of depolarization in neurons are shown to be important mediators of genetic expression patterns and molecular responses. More research is needed to fully uncover the molecular response of different types of neurons-to-activity patterns; however, known responses might be leveraged to facilitate recovery after neural damage. Physical rehabilitation through passive or active exercise modulates neurotrophic factor expression in the brain and spinal cord and can initiate cortical plasticity commensurate with functional recovery. Rehabilitation likely relies on activity-associated mechanisms; however, it may be limited in its application. Electrical and magnetic stimulation direct specific activity patterns not accessible through passive or active exercise and work synergistically to improve standing, walking, and forelimb use after injury. Here, we review emerging concepts in the molecular mechanisms of activity-derived plasticity in order to highlight opportunities that could add value to therapeutic protocols for promoting recovery of function after trauma, disease, or age-related functional decline.
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Affiliation(s)
- Matthew K Hogan
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, United States
| | - Gillian F Hamilton
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, United States
| | - Philip J Horner
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, United States
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7
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Arias JL, Mendez M, Martínez JÁ, Arias N. Differential effects of photobiomodulation interval schedules on brain cytochrome c-oxidase and proto-oncogene expression. NEUROPHOTONICS 2020; 7:045011. [PMID: 33313338 PMCID: PMC7723391 DOI: 10.1117/1.nph.7.4.045011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/28/2020] [Indexed: 06/12/2023]
Abstract
Significance: Transcranial photobiomodulation (PBM) is a noninvasive neuromodulation technique capable of producing changes in the mitochondrial cytochrome c-oxidase (CCO) activity of neurons. Although the application of PBM in clinical practice and as a neurophysiological tool is increasing, less is known about how different treatment time intervals may result in different outcomes. Aim: We evaluated the effects of different PBM treatment intervals on brain metabolic activity through the CCO and proto-oncogene expression (c-Fos). Approach: We studied PBM effects on brain CCO and c-Fos expression in three groups of animals: Control (CN, n = 8 ), long interval PBM treatment (LI, n = 5 ), and short interval PBM treatment (SI, n = 5 ). Results: Increased CCO activity in the LI group, compared to the SI and CN groups, was found in the prefrontal cortices, dorsal and ventral striatum, and hippocampus. Regarding c-Fos expression, we found a significant increase in the SI group compared to LI and CN, whereas LI showed increased c-Fos expression compared to CN in the cingulate and infralimbic cortices. Conclusions: We show the effectiveness of different PBM interval schedules in increasing brain metabolic activity or proto-oncogene expression.
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Affiliation(s)
- Jorge L. Arias
- University of Oviedo, Neuroscience Laboratory, Department of Psychology, Oviedo, Spain
- INEUROPA, Instituto de Neurociencias del Principado de Asturias, Oviedo, Spain
| | - Marta Mendez
- University of Oviedo, Neuroscience Laboratory, Department of Psychology, Oviedo, Spain
- INEUROPA, Instituto de Neurociencias del Principado de Asturias, Oviedo, Spain
| | - Juan Ángel Martínez
- INEUROPA, Instituto de Neurociencias del Principado de Asturias, Oviedo, Spain
- University of Oviedo, Escuela Politécnica de Gijón, Departamento Ingeniería Eléctrica, Electrónica, Computadores y Sistemas, Gijón, Spain
| | - Natalia Arias
- INEUROPA, Instituto de Neurociencias del Principado de Asturias, Oviedo, Spain
- Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King´s College London, Department of Basic and Clinical Neuroscience, London, United Kingdom
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8
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Iacobas DA, Iacobas S, Lee PR, Cohen JE, Fields RD. Coordinated Activity of Transcriptional Networks Responding to the Pattern of Action Potential Firing in Neurons. Genes (Basel) 2019; 10:genes10100754. [PMID: 31561430 PMCID: PMC6826514 DOI: 10.3390/genes10100754] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 12/13/2022] Open
Abstract
Transcriptional responses to the appropriate temporal pattern of action potential firing are essential for long-term adaption of neuronal properties to the functional activity of neural circuits and environmental experience. However, standard transcriptome analysis methods can be too limited in identifying critical aspects that coordinate temporal coding of action potential firing with transcriptome response. A Pearson correlation analysis was applied to determine how pairs of genes in the mouse dorsal root ganglion (DRG) neurons are coordinately expressed in response to stimulation producing the same number of action potentials by two different temporal patterns. Analysis of 4728 distinct gene-pairs related to calcium signaling, 435,711 pairs of transcription factors, 820 pairs of voltage-gated ion channels, and 86,862 pairs of calcium signaling genes with transcription factors indicated that genes become coordinately activated by distinct action potential firing patterns and this depends on the duration of stimulation. Moreover, a measure of expression variance revealed that the control of transcripts abundances is sensitive to the pattern of stimulation. Thus, action potentials impact intracellular signaling and the transcriptome in dynamic manner that not only alter gene expression levels significantly (as previously reported) but also affects the control of their expression fluctuations and profoundly remodel the transcriptional networks.
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Affiliation(s)
- Dumitru A Iacobas
- Personalized Genomics Laboratory, Center for Computational Systems Biology, Prairie View A&M University, Prairie View, TX 77446, USA.
- DP Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Sanda Iacobas
- Department of Pathology, New York Medical College, Valhalla, NY 10595, USA.
| | - Philip R Lee
- Section on Nervous System Development and Plasticity, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD 20892, USA.
| | - Jonathan E Cohen
- Division of Medical Imaging Products, U.S. Food and Drug Administration, Silver Spring, 20993 MD, USA.
| | - R Douglas Fields
- Section on Nervous System Development and Plasticity, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD 20892, USA.
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9
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Abstract
People living at sea level experience intermittent hypoxia (IH) as a consequence of sleep apnea, which is a highly prevalent respiratory disorder. Sleep apnea patients and rodents exposed to IH exhibit autonomic dysfunction manifested as increased sympathetic nerve activity and hypertension. This article highlights physiologic basis of autonomic disturbances by IH, which involves abnormal activation of the carotid body (CB) chemo reflex by reactive oxygen species (ROS).We further evaluate major molecular mechanisms underlying IH-induced ROS generation including transcriptional activation of genes encoding pro-oxidant enzymes by hypoxia-inducible factor (HIF)-1 and transcriptional repression of anti-oxidant enzyme genes by DNA methylation. Lastly, evidence is presented for CB neural activity as a major regulator of HIF-1 activation and DNA methylation by IH in the chemo reflex pathway.
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10
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Kelley P, Evans MDR, Kelley J. Making Memories: Why Time Matters. Front Hum Neurosci 2018; 12:400. [PMID: 30386221 PMCID: PMC6198140 DOI: 10.3389/fnhum.2018.00400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 09/18/2018] [Indexed: 11/29/2022] Open
Abstract
In the last decade advances in human neuroscience have identified the critical importance of time in creating long-term memories. Circadian neuroscience has established biological time functions via cellular clocks regulated by photosensitive retinal ganglion cells and the suprachiasmatic nuclei. Individuals have different circadian clocks depending on their chronotypes that vary with genetic, age, and sex. In contrast, social time is determined by time zones, daylight savings time, and education and employment hours. Social time and circadian time differences can lead to circadian desynchronization, sleep deprivation, health problems, and poor cognitive performance. Synchronizing social time to circadian biology leads to better health and learning, as demonstrated in adolescent education. In-day making memories of complex bodies of structured information in education is organized in social time and uses many different learning techniques. Research in the neuroscience of long-term memory (LTM) has demonstrated in-day time spaced learning patterns of three repetitions of information separated by two rest periods are effective in making memories in mammals and humans. This time pattern is based on the intracellular processes required in synaptic plasticity. Circadian desynchronization, sleep deprivation, and memory consolidation in sleep are less well-understood, though there has been considerable progress in neuroscience research in the last decade. The interplay of circadian, in-day and sleep neuroscience research are creating an understanding of making memories in the first 24-h that has already led to interventions that can improve health and learning.
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Affiliation(s)
- Paul Kelley
- Sleep, Circadian and Memory Neuroscience, The Open University, Milton Keynes, United Kingdom
| | - M. D. R. Evans
- Sociology and Applied Statistics Program, University of Nevada, Reno, Reno, NV, United States
- Sociology, University of Nevada, Reno, Reno, NV, United States
| | - Jonathan Kelley
- Sociology, University of Nevada, Reno, Reno, NV, United States
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11
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Noorbakhshnia M, Rashidkaboli A, Pakatchian M, Beheshti S. Agmatine attenuates methamphetamine-induced passive avoidance learning and memory and CaMKII-α gene expression deteriorations in hippocampus of rat. Physiol Behav 2018; 194:491-496. [PMID: 29908234 DOI: 10.1016/j.physbeh.2018.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 05/18/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
Methamphetamine (METH) abuse is one the most worldwide problems with wide-ranging effects on the central nervous system (CNS). Chronic METH abuse can associate with cognitive abnormalities and neurodegenerative changes in the brain. Agmatine, a cationic polyamine, has been proposed as a neuromodulator that modulates many effects of abused drugs. The aim of this study was to determine if agmatine can decrease the impairment effect of METH on memory and hippocampal CaMKII-α gene expression, a gene that plays a major role in memory. Male wistar rats (200-220 g) were allocated into 7 groups, including 5 groups of saline, METH (1, 2 mg/kg), Agmatine (5, 10 mg/kg) and 2 groups of agmatine (5, 10 mg/kg) with higher doses of METH (2 mg/kg) for 5 consecutive days (n = 8 in each group). All injections were done intraperitoneally and agmatine was administrated 10 min before METH treatment. Furthermore, Passive avoidance learning (PAL) test was assessed on the 5th day. Retention test was done 24 h after training and the rats were sacrificed immediately. Hippocampi were removed and stored at -80 °C. Finally, hippocampal CaMKII-α gene expression was measured using Quantitative Real-time PCR. Our data showed that chronic METH dose-dependently impaired PAL retrieval, as it decreased step-through latency (STL) and increased time spent in the dark compartment (TDC). While Agmatine with a higher dose (10 mg/kg) significantly decreased impairment effect of METH (2 mg/kg) on PAL and memory. Also, molecular results revealed that METH (2 mg/kg) markedly decreased hippocampal CaMKII-α gene expression while agmatine (10 mg/kg) co-adminstration prevented it. Taken together, the results propose that agmatine may provide a potential therapy for learning and memory deficits induced by METH.
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Affiliation(s)
- Maryam Noorbakhshnia
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan. Iran.
| | - Arsham Rashidkaboli
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan. Iran
| | - Mahnaz Pakatchian
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan. Iran
| | - Siamak Beheshti
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan. Iran
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12
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Doron A, Goshen I. Investigating the transition from recent to remote memory using advanced tools. Brain Res Bull 2018; 141:35-43. [DOI: 10.1016/j.brainresbull.2017.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/27/2017] [Accepted: 09/11/2017] [Indexed: 11/30/2022]
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13
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Abstract
Bipolar disease (BD) is one of the major public health burdens worldwide and more people are affected every year. Comprehensive genetic studies have associated thousands of single nucleotide polymorphisms (SNPs) with BD risk; yet, very little is known about their functional roles. Induced pluripotent stem cells (iPSCs) are powerful tools for investigating the relationship between genotype and phenotype in disease-relevant tissues and cell types. Neural cells generated from BD-specific iPSCs are thought to capture associated genetic risk factors, known and unknown, and to allow the analysis of their effects on cellular and molecular phenotypes. Interestingly, an increasing number of studies on BD-derived iPSCs report distinct alterations in neural patterning, postmitotic calcium signaling, and neuronal excitability. Importantly, these alterations are partly normalized by lithium, a first line treatment in BD. In light of these exciting findings, we discuss current challenges to the field of iPSC-based disease modelling and future steps to be taken in order to fully exploit the potential of this approach for the investigation of BD and the development of new therapies.
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14
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Pronounced Hyperactivity, Cognitive Dysfunctions, and BDNF Dysregulation in Dopamine Transporter Knock-out Rats. J Neurosci 2018; 38:1959-1972. [PMID: 29348190 DOI: 10.1523/jneurosci.1931-17.2018] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 01/07/2018] [Accepted: 01/11/2018] [Indexed: 12/16/2022] Open
Abstract
Dopamine (DA) controls many vital physiological functions and is critically involved in several neuropsychiatric disorders such as schizophrenia and attention deficit hyperactivity disorder. The major function of the plasma membrane dopamine transporter (DAT) is the rapid uptake of released DA into presynaptic nerve terminals leading to control of both the extracellular levels of DA and the intracellular stores of DA. Here, we present a newly developed strain of rats in which the gene encoding DAT knockout Rats (DAT-KO) has been disrupted by using zinc finger nuclease technology. Male and female DAT-KO rats develop normally but weigh less than heterozygote and wild-type rats and demonstrate pronounced spontaneous locomotor hyperactivity. While striatal extracellular DA lifetime and concentrations are significantly increased, the total tissue content of DA is markedly decreased demonstrating the key role of DAT in the control of DA neurotransmission. Hyperactivity of DAT-KO rats can be counteracted by amphetamine, methylphenidate, the partial Trace Amine-Associated Receptor 1 (TAAR1) agonist RO5203648 ((S)-4-(3,4-Dichloro-phenyl)-4,5-dihydro-oxazol-2-ylamine) and haloperidol. DAT-KO rats also demonstrate a deficit in working memory and sensorimotor gating tests, less propensity to develop obsessive behaviors and show strong dysregulation in frontostriatal BDNF function. DAT-KO rats could provide a novel translational model for human diseases involving aberrant DA function and/or mutations affecting DAT or related regulatory mechanisms.SIGNIFICANCE STATEMENT Here, we present a newly developed strain of rats in which the gene encoding the dopamine transporter (DAT) has been disrupted (Dopamine Transporter Knockout rats [DAT-KO rats]). DAT-KO rats display functional hyperdopaminergia accompanied by pronounced spontaneous locomotor hyperactivity. Hyperactivity of DAT-KO rats can be counteracted by amphetamine, methylphenidate, and a few other compounds exerting inhibitory action on dopamine-dependent hyperactivity. DAT-KO rats also demonstrate cognitive deficits in working memory and sensorimotor gating tests, less propensity to develop compulsive behaviors, and strong dysregulation in frontostriatal BDNF function. These observations highlight the key role of DAT in the control of brain dopaminergic transmission. DAT-KO rats could provide a novel translational model for human diseases involving aberrant dopamine functions.
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Prabhakar NR. Carotid body chemoreflex: a driver of autonomic abnormalities in sleep apnoea. Exp Physiol 2018; 101:975-85. [PMID: 27474260 DOI: 10.1113/ep085624] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/13/2016] [Indexed: 12/14/2022]
Abstract
What is the topic of this review? This article presents emerging evidence for heightened carotid body chemoreflex activity as a major driver of sympathetic activation and hypertension in sleep apnoea patients. What advances does it heighlight? This article discusses the recent advances on cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex in experimental models of sleep apnoea. The carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen concentration, and the resulting chemoreflex is a potent regulator of the sympathetic tone, blood pressure and breathing. Sleep apnoea is a disease of the respiratory system that affects several million adult humans. Apnoeas occur during sleep, often as a result of obstruction of the upper airway (obstructive sleep apnoea) or because of defective respiratory rhythm generation by the CNS (central sleep apnoea). Patients with sleep apnoea exhibit several co-morbidities, with the most notable among them being heightened sympathetic nerve activity and hypertension. Emerging evidence suggests that intermittent hypoxia resulting from periodic apnoea stimulates the carotid body, and the ensuing chemoreflex mediates the increased sympathetic tone and hypertension in sleep apnoea patients. Rodent models of intermittent hypoxia that simulate the O2 saturation profiles encountered during sleep apnoea have provided important insights into the cellular and molecular mechanisms underlying the heightened carotid body chemoreflex. This article describes how intermittent hypoxia affects the carotid body function and discusses the cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, IL, USA
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16
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Abstract
Memory is an adaptation to particular temporal properties of past events, such as the frequency of occurrence of a stimulus or the coincidence of multiple stimuli. In neurons, this adaptation can be understood in terms of a hierarchical system of molecular and cellular time windows, which collectively retain information from the past. We propose that this system makes various timescales of past experience simultaneously available for future adjustment of behavior. More generally, we propose that the ability to detect and respond to temporally structured information underlies the nervous system's capacity to encode and store a memory at molecular, cellular, synaptic, and circuit levels.
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Affiliation(s)
| | - Thomas James Carew
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
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17
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Homeostatic interplay between electrical activity and neuronal apoptosis in the developing neocortex. Neuroscience 2017; 358:190-200. [PMID: 28663094 DOI: 10.1016/j.neuroscience.2017.06.030] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/07/2017] [Accepted: 06/19/2017] [Indexed: 12/15/2022]
Abstract
An intriguing feature of nervous system development in most animal species is that the initial number of generated neurons is higher than the number of neurons incorporated into mature circuits. A substantial portion of neurons is indeed eliminated via apoptosis during a short time window - in rodents the first two postnatal weeks. While it is well established that neurotrophic factors play a central role in controlling neuronal survival and apoptosis in the peripheral nervous system (PNS), the situation is less clear in the central nervous system (CNS). In postnatal rodent neocortex, the peak of apoptosis coincides with the occurrence of spontaneous, synchronous activity patterns. In this article, we review recent results that demonstrate the important role of electrical activity for neuronal survival in the neocortex, describe the role of Ca2+ and neurotrophic factors in translating electrical activity into pro-survival signals, and finally discuss the clinical impact of the tight relation between electrical activity and neuronal survival versus apoptosis.
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18
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Gene networks activated by specific patterns of action potentials in dorsal root ganglia neurons. Sci Rep 2017; 7:43765. [PMID: 28256583 PMCID: PMC5335607 DOI: 10.1038/srep43765] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/23/2017] [Indexed: 12/17/2022] Open
Abstract
Gene regulatory networks underlie the long-term changes in cell specification, growth of synaptic connections, and adaptation that occur throughout neonatal and postnatal life. Here we show that the transcriptional response in neurons is exquisitely sensitive to the temporal nature of action potential firing patterns. Neurons were electrically stimulated with the same number of action potentials, but with different inter-burst intervals. We found that these subtle alterations in the timing of action potential firing differentially regulates hundreds of genes, across many functional categories, through the activation or repression of distinct transcriptional networks. Our results demonstrate that the transcriptional response in neurons to environmental stimuli, coded in the pattern of action potential firing, can be very sensitive to the temporal nature of action potential delivery rather than the intensity of stimulation or the total number of action potentials delivered. These data identify temporal kinetics of action potential firing as critical components regulating intracellular signalling pathways and gene expression in neurons to extracellular cues during early development and throughout life.
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19
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Stüttgen MC, Nonkes LJP, Geis HRAP, Tiesinga PH, Houweling AR. Temporally precise control of single-neuron spiking by juxtacellular nanostimulation. J Neurophysiol 2017; 117:1363-1378. [PMID: 28077663 DOI: 10.1152/jn.00479.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 11/22/2022] Open
Abstract
Temporal patterns of action potentials influence a variety of activity-dependent intra- and intercellular processes and play an important role in theories of neural coding. Elucidating the mechanisms underlying these phenomena requires imposing spike trains with precisely defined patterns, but this has been challenging due to the limitations of existing stimulation techniques. Here we present a new nanostimulation method providing control over the action potential output of individual cortical neurons. Spikes are elicited through the juxtacellular application of short-duration fluctuating currents ("kurzpulses"), allowing for the sub-millisecond precise and reproducible induction of arbitrary patterns of action potentials at all physiologically relevant firing frequencies (<120 Hz), including minute-long spike trains recorded in freely moving animals. We systematically compared our method to whole cell current injection, as well as optogenetic stimulation, and show that nanostimulation performance compares favorably with these techniques. This new nanostimulation approach is easily applied, can be readily performed in awake behaving animals, and thus promises to be a powerful tool for systematic investigations into the temporal elements of neural codes, as well as the mechanisms underlying a wide variety of activity-dependent cellular processes.NEW & NOTEWORTHY Assessing the impact of temporal features of neuronal spike trains requires imposing arbitrary patterns of spiking on individual neurons during behavior, but this has been difficult to achieve due to limitations of existing stimulation methods. We present a technique that overcomes these limitations by using carefully designed short-duration fluctuating juxtacellular current injections, which allow for the precise and reliable evocation of arbitrary patterns of neuronal spikes in single neurons in vivo.
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Affiliation(s)
- Maik C Stüttgen
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands; .,Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.,Focus Program Translational Neuroscience, Johannes Gutenberg University, Mainz, Germany
| | - Lourens J P Nonkes
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - H Rüdiger A P Geis
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.,Neuronal Networks Group, German Center for Neurodegenerative Diseases, Bonn, Germany; and
| | - Paul H Tiesinga
- Department of Neuroinformatics, Donders Centre for Neuroscience, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Arthur R Houweling
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands
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20
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The ontogenetic development of neurons containing calcium-binding proteins in the septum of the guinea pig: Late onset of parvalbumin immunoreactivity versus calbindin and calretinin. J Chem Neuroanat 2017; 79:22-31. [DOI: 10.1016/j.jchemneu.2016.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/07/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
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21
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Yan X, Liu J, Zhang Z, Li W, Sun S, Zhao J, Dong X, Qian J, Sun H. Low-level laser irradiation modulates brain-derived neurotrophic factor mRNA transcription through calcium-dependent activation of the ERK/CREB pathway. Lasers Med Sci 2016; 32:169-180. [PMID: 27864646 DOI: 10.1007/s10103-016-2099-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 10/17/2016] [Indexed: 12/29/2022]
Abstract
Low-level laser (LLL) irradiation has been reported to promote neuronal differentiation, but the mechanism remains unclear. Brain-derived neurotrophic factor (BDNF) has been confirmed to be one of the most important neurotrophic factors because it is critical for the differentiation and survival of neurons during development. Thus, this study aimed to investigate the effects of LLL irradiation on Bdnf messenger RNA (mRNA) transcription and the molecular pathway involved in LLL-induced Bdnf mRNA transcription in cultured dorsal root ganglion neurons (DRGNs) using Ca2+ imaging, pharmacological detections, RNA interference, immunocytochemistry assay, Western blot, and qPCR analysis. We show here that LLL induced increases in the [Ca2+] i level, Bdnf mRNA transcription, cAMP-response element-binding protein (CREB) phosphorylation, and extracellular signal-regulated kinase (ERK) phosphorylation, mediated by Ca2+ release via inositol triphosphate receptor (IP3R)-sensitive calcium (Ca2+) stores. Blockade of Ca2+ increase suppressed Bdnf mRNA transcription, CREB phosphorylation, and ERK phosphorylation. Downregulation of phosphorylated (p)-CREB reduced Bdnf mRNA transcription triggered by LLL. Furthermore, blockade of ERK using PD98059 inhibitor reduced p-CREB and Bdnf mRNA transcription induced by LLL. Taken together, these findings establish the Ca2+-ERK-CREB cascade as a potential signaling pathway involved in LLL-induced Bdnf mRNA transcription. To our knowledge, this is the first report of the mechanisms of Ca2+-dependent Bdnf mRNA transcription triggered by LLL. These findings may help further explore the complex molecular signaling networks in LLL-triggered nerve regeneration in vivo and may also provide experimental evidence for the development of LLL for clinical applications.
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Affiliation(s)
- Xiaodong Yan
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, 569 Xinsi Road, Xi'an, 710038, China
| | - Juanfang Liu
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Zhengping Zhang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, China
| | - Wenhao Li
- Cadet Brigade, Fourth Military Medical University, Xi'an, 710032, China
| | - Siguo Sun
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, 569 Xinsi Road, Xi'an, 710038, China
| | - Jian Zhao
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, 569 Xinsi Road, Xi'an, 710038, China
| | - Xin Dong
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, 569 Xinsi Road, Xi'an, 710038, China
| | - Jixian Qian
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, 569 Xinsi Road, Xi'an, 710038, China.
| | - Honghui Sun
- Department of Orthopaedics, Tangdu Hospital, Fourth Military Medical University, 569 Xinsi Road, Xi'an, 710038, China.
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22
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Żakowski W. Neurochemistry of the Anterior Thalamic Nuclei. Mol Neurobiol 2016; 54:5248-5263. [DOI: 10.1007/s12035-016-0077-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/23/2016] [Indexed: 01/19/2023]
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23
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Dong J, Gao L, Han J, Zhang J, Zheng J. Dopamine Attenuates Ketamine-Induced Neuronal Apoptosis in the Developing Rat Retina Independent of Early Synchronized Spontaneous Network Activity. Mol Neurobiol 2016; 54:3407-3417. [PMID: 27177547 DOI: 10.1007/s12035-016-9914-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 05/03/2016] [Indexed: 01/08/2023]
Abstract
Deprivation of spontaneous rhythmic electrical activity in early development by anesthesia administration, among other interventions, induces neuronal apoptosis. However, it is unclear whether enhancement of neuronal electrical activity attenuates neuronal apoptosis in either normal development or after anesthesia exposure. The present study investigated the effects of dopamine, an enhancer of spontaneous rhythmic electrical activity, on ketamine-induced neuronal apoptosis in the developing rat retina. TUNEL and immunohistochemical assays indicated that ketamine time- and dose-dependently aggravated physiological and ketamine-induced apoptosis and inhibited early-synchronized spontaneous network activity. Dopamine administration reversed ketamine-induced neuronal apoptosis, but did not reverse the inhibitory effects of ketamine on early synchronized spontaneous network activity despite enhancing it in controls. Blockade of D1, D2, and A2A receptors and inhibition of cAMP/PKA signaling partially antagonized the protective effect of dopamine against ketamine-induced apoptosis. Together, these data indicate that dopamine attenuates ketamine-induced neuronal apoptosis in the developing rat retina by activating the D1, D2, and A2A receptors, and upregulating cAMP/PKA signaling, rather than through modulation of early synchronized spontaneous network activity.
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Affiliation(s)
- Jing Dong
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingqi Gao
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Junde Han
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Junjie Zhang
- Department of Anesthesiology, Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, 1111 Xianxia Road, Shanghai, 200050, China.
| | - Jijian Zheng
- Department of Anesthesiology, Shanghai Children's Medical Center, Shanghai Jiao Tong University, 1678 Dongfang Road, Shanghai, 200127, China.
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24
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Trafficking of Na+/Ca2+ exchanger to the site of persistent inflammation in nociceptive afferents. J Neurosci 2015; 35:8423-32. [PMID: 26041911 DOI: 10.1523/jneurosci.3597-14.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Persistent inflammation results in an increase in the amplitude and duration of depolarization-evoked Ca(2+) transients in putative nociceptive afferents. Previous data indicated that these changes were the result of neither increased neuronal excitability nor an increase in the amplitude of depolarization. Subsequent data also ruled out an increase in voltage-gated Ca(2+) currents and recruitment of Ca(2+)-induced Ca(2+) release. Parametric studies indicated that the inflammation-induced increase in the duration of the evoked Ca(2+) transient required a relatively large and long-lasting increase in the concentration of intracellular Ca(2+) implicating the Na(+)/Ca(2+) exchanger (NCX), a major Ca(2+) extrusion mechanism activated with high intracellular Ca(2+) loads. The contribution of NCX to the inflammation-induced increase in the evoked Ca(2+) transient in rat sensory neurons was tested using fura-2 AM imaging and electrophysiological recordings. Changes in NCX expression and protein were assessed with real-time PCR and Western blot analysis, respectively. An inflammation-induced decrease in NCX activity was observed in a subpopulation of putative nociceptive neurons innervating the site of inflammation. The time course of the decrease in NCX activity paralleled that of the inflammation-induced changes in nociceptive behavior. The change in NCX3 in the cell body was associated with a decrease in NCX3 protein in the ganglia, an increase in the peripheral nerve (sciatic) yet no change in the central root. This single response to inflammation is associated with changes in at least three different segments of the primary afferent, all of which are likely to contribute to the dynamic response to persistent inflammation.
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25
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Yilmaz E, Gold MS. Sensory neuron subpopulation-specific dysregulation of intracellular calcium in a rat model of chemotherapy-induced peripheral neuropathy. Neuroscience 2015; 300:210-8. [PMID: 25982563 PMCID: PMC4485584 DOI: 10.1016/j.neuroscience.2015.05.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/01/2015] [Accepted: 05/07/2015] [Indexed: 02/06/2023]
Abstract
The purpose of the present study was to test the prediction that the unique manifestation of chemotherapeutic-induced peripheral neuropathy (CIPN) would be reflected in a specific pattern of changes in the regulation of the intracellular Ca(2+) concentration ([Ca(2+)]i) in subpopulations of cutaneous neurons. To test this prediction, we characterized the pattern of changes in mechanical nociceptive threshold associated with paclitaxel administration (2mg/kg, iv, every other day for four days), as well as the impact of target of innervation and paclitaxel treatment on the regulation of [Ca(2+)]i in subpopulations of putative nociceptive and non-nociceptive neurons. Neurons innervating the glabrous and hairy skin of the hindpaw as well as the thigh were identified with retrograde tracers, and fura-2 was used to assess changes in [Ca(2+)]i. Paclitaxel was associated with a persistent decrease in mechanical nociceptive threshold in response to stimuli applied to the glabrous skin of the hindpaw, but not the hairy skin of the hindpaw or the thigh. However, in both putative nociceptive and non-nociceptive neurons, resting [Ca(2+)]i was significantly lower in neurons innervating the thigh after treatment. The magnitude of the depolarization-evoked Ca(2+) transient was also lower in putative non-nociceptive thigh neurons. More interestingly, while paclitaxel had no detectable influence on either resting or depolarization-evoked Ca(2+) transients in putative non-nociceptive neurons, in putative nociceptive neurons there was a subpopulation-specific decrease in the duration of the evoked Ca(2+) transient that was largely restricted to neurons innervating the glabrous skin. These results suggest that peripheral nerve length alone, does not account for the selective distribution of CIPN symptoms. Rather, they suggest the symptoms of CIPN reflect an interaction between the toxic actions of the therapeutic and unique properties of the neurons deleteriously impacted.
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Affiliation(s)
- E Yilmaz
- Center for Neuroscience, University of Pittsburgh, United States; Center for Pain Research, United States
| | - M S Gold
- Center for Neuroscience, University of Pittsburgh, United States; Center for Pain Research, United States; Department of Anesthesiology, University of Pittsburgh School of Medicine, United States.
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26
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Chin-Smith EC, Willey FR, Slater DM, Taggart MJ, Tribe RM. Nuclear factor of activated T-cell isoform expression and regulation in human myometrium. Reprod Biol Endocrinol 2015; 13:83. [PMID: 26238508 PMCID: PMC4523953 DOI: 10.1186/s12958-015-0086-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 07/30/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND During pregnancy, myometrial gene and protein expression is tightly regulated to accommodate fetal growth, promote quiescence and ultimately prepare for the onset of labour. It is proposed that changes in calcium signalling, may contribute to regulating gene expression and that nuclear factor of activated T-cell (NFAT) transcription factors (isoforms c1-c4) may be involved. Currently, there is little information regarding NFAT expression and regulation in myometrium. METHODS This study examined NFAT isoform mRNA expression in human myometrial tissue and cells from pregnant women using quantitative PCR. The effects of the Ca(2+) ionophore A23187 and in vitro stretch (25 % elongation, static strain; Flexercell FX-4000 Tension System) on NFAT expression were determined in cultured human myometrial cells. RESULTS Human myometrial tissue and cultured cells expressed NFATc1-c4 mRNA. NFATc2 gene expression in cultured cells was increased in response to 6 h stretch (11.5 fold, P < 0.001, n = 6) and calcium ionophore (A23187, 5 μM) treatment (20.6 fold, P < 0.001, n = 6). This response to stretch was significantly reduced (90 %, P < 0.001, n = 10) in the presence of an intracellular calcium chelator, BAPTA-AM (20 μM). CONCLUSIONS These data suggest that NFATc2 expression is regulated by intracellular calcium and in vitro stretch, and that the stretch response in human myometrial cells is dependent upon intracellular calcium signalling pathways. Our findings indicate a potentially unique role for NFATc2 in mediating stretch-induced gene expression per se and warrant further exploration in relation to the mechanisms promoting uterine smooth muscle growth in early pregnancy and/or labour.
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Affiliation(s)
- Evonne C Chin-Smith
- Division of Women's Health, King's College London, Women's Health Academic Centre KHP, St Thomas' Hospital, 10th Floor, North Wing, Westminster Bridge Road, London, SE1 7EH, UK.
| | - Frances R Willey
- Division of Women's Health, King's College London, Women's Health Academic Centre KHP, St Thomas' Hospital, 10th Floor, North Wing, Westminster Bridge Road, London, SE1 7EH, UK.
| | - Donna M Slater
- Physiology and Pharmacology, Cumming School of Medicine, Alberta Children's Hospital Research Institute for Child and Maternal Health, University of Calgary, Alberta, T2N 4 N1, Canada.
| | - Michael J Taggart
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, NE2 4HH, UK.
| | - Rachel M Tribe
- Division of Women's Health, King's College London, Women's Health Academic Centre KHP, St Thomas' Hospital, 10th Floor, North Wing, Westminster Bridge Road, London, SE1 7EH, UK.
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27
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Cohen JE, Lee PR, Fields RD. Systematic identification of 3'-UTR regulatory elements in activity-dependent mRNA stability in hippocampal neurons. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0509. [PMID: 25135970 PMCID: PMC4142030 DOI: 10.1098/rstb.2013.0509] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Ongoing neuronal activity during development and plasticity acts to refine synaptic connections and contributes to the induction of plasticity and ultimately long-term memory storage. Activity-dependent, post-transcriptional control of mRNAs occurs through transport to axonal and dendritic compartments, local translation and mRNA stability. We have identified a mechanism that contributes to activity-dependent regulation of mRNA stability during synaptic plasticity in rat hippocampal neurons. In this study, we demonstrate rapid, post-transcriptional control over process-enriched mRNAs by neuronal activity. Systematic analysis of the 3'-UTRs of destabilized transcripts, identifies enrichment in sequence motifs corresponding to microRNA (miRNA)-binding sites. The miRNAs that were identified, miR-326-3p/miR-330-5p, miR-485-5p, miR-666-3p and miR-761 are predicted to regulate networks of genes important in plasticity and development. We find that these miRNAs are developmentally regulated in the hippocampus, many increasing by postnatal day 14. We further find that miR-485-5p controls NGF-induced neurite outgrowth in PC12 cells, tau expression and axonal development in hippocampal neurons. miRNAs can function at the synapse to rapidly control and affect short- and long-term changes at the synapse. These processes likely occur during refinement of synaptic connections and contribute to the induction of plasticity and learning and memory.
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Affiliation(s)
- Jonathan E Cohen
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child and Human Development, National Institute of Health, Building 35, Room 2A211, Bethesda, MD 20892-3714, USA
| | - Philip R Lee
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child and Human Development, National Institute of Health, Building 35, Room 2A211, Bethesda, MD 20892-3714, USA
| | - R Douglas Fields
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child and Human Development, National Institute of Health, Building 35, Room 2A211, Bethesda, MD 20892-3714, USA
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28
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Kumar GK, Nanduri J, Peng YJ, Prabhakar NR. Neuromolecular mechanisms mediating the effects of chronic intermittent hypoxia on adrenal medulla. Respir Physiol Neurobiol 2015; 209:115-9. [PMID: 25583660 DOI: 10.1016/j.resp.2015.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/01/2015] [Indexed: 10/24/2022]
Abstract
Sleep disordered breathing (SDB) with recurrent apnea is a major health problem affecting several million adult men and women. Humans with SDB are prone to develop hypertension. Studies on rodents established that exposure to chronic intermittent hypoxia (CIH) alone is sufficient to induce hypertension similar to that seen in patients with SDB. Available evidence from studies on experimental animals suggests that catecholamines secreted from adrenal medulla (AM), an end-organ of the sympathetic nervous system is a major contributor to CIH-induced hypertension. In this article, we present an overview of our current understanding on how CIH reconfigures AM function and highlight recent findings on the underlying cellular and molecular mechanisms.
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Affiliation(s)
- Ganesh K Kumar
- Institute for Integrative Physiology and Center for Systems Biology of O(2) Sensing, Biological Sciences Division, University of Chicago, IL, USA.
| | - Jayasri Nanduri
- Institute for Integrative Physiology and Center for Systems Biology of O(2) Sensing, Biological Sciences Division, University of Chicago, IL, USA
| | - Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology of O(2) Sensing, Biological Sciences Division, University of Chicago, IL, USA
| | - Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O(2) Sensing, Biological Sciences Division, University of Chicago, IL, USA
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29
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Hagenston AM, Simonetti M. Neuronal calcium signaling in chronic pain. Cell Tissue Res 2014; 357:407-26. [PMID: 25012522 DOI: 10.1007/s00441-014-1942-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/03/2014] [Indexed: 01/03/2023]
Abstract
Acute physiological pain, the unpleasant sensory response to a noxious stimulus, is essential for animals and humans to avoid potential injury. Pathological pain that persists after the original insult or injury has subsided, however, not only results in individual suffering but also imposes a significant cost on society. Improving treatments for long-lasting pathological pain requires a comprehensive understanding of the biological mechanisms underlying pain perception and the development of pain chronicity. In this review, we aim to highlight some of the major findings related to the involvement of neuronal calcium signaling in the processes that mediate chronic pain.
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Affiliation(s)
- Anna M Hagenston
- University of Heidelberg, Neurobiology, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany,
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Peng YJ, Yuan G, Khan S, Nanduri J, Makarenko VV, Reddy VD, Vasavda C, Kumar GK, Semenza GL, Prabhakar NR. Regulation of hypoxia-inducible factor-α isoforms and redox state by carotid body neural activity in rats. J Physiol 2014; 592:3841-58. [PMID: 24973414 DOI: 10.1113/jphysiol.2014.273789] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Previous studies reported that chronic intermittent hypoxia (CIH) results in an imbalanced expression of hypoxia-inducible factor-α (HIF-α) isoforms and oxidative stress in rodents, which may be due either to the direct effect of CIH or indirectly via hitherto uncharacterized mechanism(s). As neural activity is a potent regulator of gene transcription, we hypothesized that carotid body (CB) neural activity contributes to CIH-induced HIF-α isoform expression and oxidative stress in the chemoreflex pathway. Experiments were performed on adult rats exposed to CIH for 10 days. Rats exposed to CIH exhibited: increased HIF-1α and decreased HIF-2α expression; increased NADPH oxidase 2 and decreased superoxide dismutase 2 expression; and oxidative stress in the nucleus tractus solitarius and rostral ventrolateral medulla as well as in the adrenal medulla (AM), a major end organ of the sympathetic nervous system. Selective ablation of the CB abolished these effects. In the AM, sympathetic activation by the CB chemoreflex mediates CIH-induced HIF-α isoform imbalance via muscarinic acetylcholine receptor-mediated Ca(2+) influx, and the resultant activation of mammalian target of rapamycin pathway and calpain proteases. Rats exposed to CIH presented with hypertension, elevated sympathetic activity and increased circulating catecholamines. Selective ablation of either the CB (afferent pathway) or sympathetic innervation to the AM (efferent pathway) abolished these effects. These observations uncover CB neural activity-dependent regulation of HIF-α isoforms and the redox state by CIH in the central and peripheral nervous systems associated with the chemoreflex.
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Affiliation(s)
- Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Guoxiang Yuan
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Shakil Khan
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Jayasri Nanduri
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Vladislav V Makarenko
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Vaddi Damodara Reddy
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Chirag Vasavda
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Ganesh K Kumar
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
| | - Gregg L Semenza
- Institute for Cell Engineering, Departments of Pediatrics, Medicine, Oncology, Radiation Oncology and Biological Chemistry, and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology for O2 Sensing, Biological Sciences Division, University of Chicago, IL, 60637, USA
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DeBerry JJ, Schwartz ES, Davis BM. TRPA1 mediates bladder hyperalgesia in a mouse model of cystitis. Pain 2014; 155:1280-1287. [PMID: 24704367 DOI: 10.1016/j.pain.2014.03.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/13/2014] [Accepted: 03/27/2014] [Indexed: 01/07/2023]
Abstract
Urinary bladder pain is a primary symptom associated with interstitial cystitis/painful bladder syndrome. We used systemic injections of cyclophosphamide (CYP), an alkylating antineoplastic agent, to induce cystitis and examine the roles of 2 channels previously demonstrated to be required for inflammatory visceral hyperalgesia: transient receptor potential vanilloid-1 (TRPV1) and ankyrin-1 (TRPA1). Injection of CYP (100 mg/kg, i.p.) every other day for 5 days was accompanied by bladder edema and urothelial ulceration, but without significant plasma extravasation or infiltration of neutrophils. Toluidine blue staining showed a significant increase in the number of degranulated bladder mast cells after CYP treatment. Despite this mild pathology, CYP-treated mice exhibited bladder hyperalgesia 1 day after the final injection that persisted 7 days later. Although many previous studies of visceral hyperalgesia have reported changes in dorsal root ganglion neuron TRPV1 expression and/or function, we found no change in bladder afferent TRPV1 expression or sensitivity on the basis of the percentage of bladder afferents responsive to capsaicin, including at submaximal concentrations. In contrast, the percentage of bladder afferents expressing functional TRPA1 protein (i.e., those responsive to mustard oil) increased ∼2.5-fold 1 day after CYP treatment, and remained significantly elevated 7 days later. Moreover, bladder hyperalgesia was reversed by acute treatment with the TRPA1 antagonist HC-030031 (300 mg/kg, i.p.). Our results indicate that CYP-induced bladder hyperalgesia can be induced without robust inflammation or changes in primary afferent TRPV1. However, significant changes were observed in TRPA1 expression, and blockade of TRPA1 alleviated CYP-induced bladder hyperalgesia.
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Affiliation(s)
- Jennifer J DeBerry
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15261, USA Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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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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Scheff NN, Lu SG, Gold MS. Contribution of endoplasmic reticulum Ca2+ regulatory mechanisms to the inflammation-induced increase in the evoked Ca2+ transient in rat cutaneous dorsal root ganglion neurons. Cell Calcium 2013; 54:46-56. [PMID: 23642703 DOI: 10.1016/j.ceca.2013.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 04/02/2013] [Accepted: 04/04/2013] [Indexed: 12/21/2022]
Abstract
Persistent inflammation results in an increase in the magnitude and duration of high K(+)-evoked Ca(2+) transients in putative nociceptive cutaneous dorsal root ganglion (DRG) neurons. The purpose of the present study was to determine whether recruitment of Ca(2+)-induced Ca(2+) release (CICR) contributes to these inflammation-induced changes. Acutely dissociated, retrogradely labeled cutaneous DRG neurons from naïve and complete Freund's adjuvant inflamed adult male Sprague-Dawley rats were studied with ratiometric microfluorimetry. Ryanodine only attenuated the duration but not magnitude of the high K(+)-evoked Ca(2+) transient in neurons from inflamed rats. However, there was no significant impact of inflammation on the potency or efficacy of ryanodine-induced block of the caffeine-evoked Ca(2+) transient, or the impact of sarco-endoplasmic reticulum ATPase (SERCA) inhibition on the high K(+)-evoked Ca(2+) transient. Furthermore, while there was no change in the magnitude, an inflammation-induced increase in the duration of the caffeine-evoked Ca(2+) transient was only observed with a prolonged caffeine application. In contrast to the high K(+)-evoked Ca(2+) transient, there was no evidence of direct mitochondrial involvement or that of the Ca(2+) extrusion mechanism, the Na(+)/Ca(2+) exchanger, on the caffeine-evoked Ca(2+) transient, and block of SERCA only increased the duration of this transient. These results indicate the presence of Ca(2+) regulatory domains in cutaneous nociceptive DRG neurons within which cytosolic Ca(2+) increased via influx and release are highly segregated. Furthermore, our results suggest that changes in neither CICR machinery nor the coupling between Ca(2+) influx and CICR are primarily responsible for the inflammation-induced changes in the evoked Ca(2+) transient.
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Affiliation(s)
- Nicole N Scheff
- Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Qian A, Song D, Li Y, Liu X, Tang D, Yao W, Yuan Y. Role of voltage gated Ca2+ channels in rat visceral hypersensitivity change induced by 2,4,6-trinitrobenzene sulfonic acid. Mol Pain 2013; 9:15. [PMID: 23537331 PMCID: PMC3626538 DOI: 10.1186/1744-8069-9-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 03/22/2013] [Indexed: 11/10/2022] Open
Abstract
Background Visceral pain is common symptom involved in many gastrointestinal disorders such as inflammatory bowel disease. The underlying molecular mechanisms remain elusive. We investigated the molecular mechanisms and the role for voltage gated calcium channel (VGCC) in the pathogenesis in a rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced visceral inflammatory hypersensitivity. Results Using Agilent cDNA arrays, we found 172 genes changed significantly in dorsal root ganglia (DRG) of TNBS treated rats. Among these changed genes, Cav1.2 and Cav2.3 were significantly up-regulated. Then the RT-PCR and Western blot further confirmed the up-regulation of Cav1.2 and Cav2.3. The whole cell patch clamp recording of acutely dissociated colonic specific DRG neurons showed that the peak IBa density was significantly increased in colonic neurons of TNBS treated rats compared with control rats (−127.82 ± 20.82 pA/pF Vs −91.67 ± 19.02 pA/pF, n = 9, *P < 0.05). To distinguish the different type of calcium currents with the corresponding selective channel blockers, we found that L-type (−38.56 ± 3.97 pA/pF Vs −25.75 ± 3.35 pA/pF, n = 9, * P < 0.05) and R-type (−13.31 ± 1.36 pA/pF Vs −8.60 ± 1.25 pA/pF, n = 9, * P < 0.05) calcium current density were significantly increased in colonic DRG neurons of TNBS treated rats compared with control rats. In addition, pharmacological blockade with L-type antagonist (nimodipine) and R-type antagonist (SNX-482) with intrathecal injection attenuates visceral pain in TNBS induced inflammatory visceral hypersensitivity. Conclusion Cav1.2 and Cav2.3 in colonic primary sensory neurons play an important role in visceral inflammatory hyperalgesia, which maybe the potential therapeutic targets.
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Affiliation(s)
- Aihua Qian
- Department of Gastroenterology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
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Żakowski W, Robak A. Developmental changes of calretinin immunoreactivity in the anterior thalamic nuclei of the guinea pig. J Chem Neuroanat 2013; 47:28-34. [DOI: 10.1016/j.jchemneu.2012.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/27/2012] [Accepted: 10/22/2012] [Indexed: 10/27/2022]
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Dhumpa R, Roper MG. Temporal gradients in microfluidic systems to probe cellular dynamics: a review. Anal Chim Acta 2012; 743:9-18. [PMID: 22882819 DOI: 10.1016/j.aca.2012.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/04/2012] [Accepted: 07/04/2012] [Indexed: 11/18/2022]
Abstract
Microfluidic devices have found a unique place in cellular studies due to the ease of fabrication, their ability to provide long-term culture, or the seamless integration of downstream measurements into the devices. The accurate and precise control of fluid flows also allows unique stimulant profiles to be applied to cells that have been difficult to perform with conventional devices. In this review, we describe and provide examples of microfluidic systems that have been used to generate temporal gradients of stimulants, such as waveforms or pulses, and how these profiles have been used to produce biological insights into mammalian cells that are not typically revealed under static concentration gradients. We also discuss the inherent analytical challenges associated with producing and maintaining temporal gradients in these devices.
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Affiliation(s)
- Raghuram Dhumpa
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, United States
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Vytla D, Combs-Bachmann RE, Hussey AM, McCarron ST, McCarthy DS, Chambers JJ. Prodrug approaches to reduce hyperexcitation in the CNS. Adv Drug Deliv Rev 2012; 64:666-85. [PMID: 22138074 DOI: 10.1016/j.addr.2011.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 11/15/2011] [Accepted: 11/15/2011] [Indexed: 01/11/2023]
Abstract
Hyperexcitation in the central nervous system is the root cause of a number of disorders of the brain ranging from acute injury to chronic and progressive diseases. The major limitation to treatment of these ailments is the miniscule, yet formidable blood-brain barrier. To deliver therapeutic agents to the site of desired action, a number of biomedical engineering strategies have been developed including prodrug formulations that allow for either passive diffusion or active transport across this barrier. In the case of prodrugs, once in the brain compartment, the active therapeutic agent is released. In this review, we discuss in some detail a number of factors related to treatment of central nervous system hyperexcitation including molecular targets, disorders, prodrug strategies, and focused case studies of a number of therapeutics that are at a variety of stages of clinical development.
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Affiliation(s)
- Devaiah Vytla
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States
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Verkhratsky A, Rodríguez JJ, Parpura V. Calcium signalling in astroglia. Mol Cell Endocrinol 2012; 353:45-56. [PMID: 21945602 DOI: 10.1016/j.mce.2011.08.039] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 08/28/2011] [Accepted: 08/31/2011] [Indexed: 12/15/2022]
Abstract
Astroglia possess excitability based on movements of Ca(2+) ions between intracellular compartments and plasmalemmal Ca(2+) fluxes. This "Ca(2+) excitability" is controlled by several families of proteins located in the plasma membrane, within the cytosol and in the intracellular organelles, most notably in the endoplasmic reticulum (ER) and mitochondria. Accumulation of cytosolic Ca(2+) can be caused by the entry of Ca(2+) from the extracellular space through ionotropic receptors and store-operated channels expressed in astrocytes. Plasmalemmal Ca(2+) ATP-ase and sodium-calcium exchanger extrude cytosolic Ca(2+) to the extracellular space; the exchanger can also operate in reverse, depending of the intercellular Na(+) concentration, to deliver Ca(2+) to the cytosol. The ER internal store possesses inositol 1,4,5-trisphosphate receptors which can be activated upon stimulation of astrocytes through a multiple plasma membrane metabotropic G-protein coupled receptors. This leads to release of Ca(2+) from the ER and its elevation in the cytosol, the level of which can be modulated by mitochondria. The mitochondrial uniporter takes up Ca(2+) into the matrix, while free Ca(2+) exits the matrix through the mitochondrial Na(+)/Ca(2+) exchanger as well as via transient openings of the mitochondrial permeability transition pore. One of the prominent consequences of astroglial Ca(2+) excitability is gliotransmission, a release of transmitters from astroglia which can lead to signalling to adjacent neurones.
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Farinelli M, Heitz FD, Grewe BF, Tyagarajan SK, Helmchen F, Mansuy IM. Selective regulation of NR2B by protein phosphatase-1 for the control of the NMDA receptor in neuroprotection. PLoS One 2012; 7:e34047. [PMID: 22479519 PMCID: PMC3316588 DOI: 10.1371/journal.pone.0034047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 02/25/2012] [Indexed: 11/24/2022] Open
Abstract
An imbalance between pro-survival and pro-death pathways in brain cells can lead to neuronal cell death and neurodegeneration. While such imbalance is known to be associated with alterations in glutamatergic and Ca2+ signaling, the underlying mechanisms remain undefined. We identified the protein Ser/Thr phosphatase protein phosphatase-1 (PP1), an enzyme associated with glutamate receptors, as a key trigger of survival pathways that can prevent neuronal death and neurodegeneration in the adult hippocampus. We show that PP1α overexpression in hippocampal neurons limits NMDA receptor overactivation and Ca2+ overload during an excitotoxic event, while PP1 inhibition favors Ca2+ overload and cell death. The protective effect of PP1 is associated with a selective dephosphorylation on a residue phosphorylated by CaMKIIα on the NMDA receptor subunit NR2B, which promotes pro-survival pathways and associated transcriptional programs. These results reveal a novel contributor to the mechanisms of neuroprotection and underscore the importance of PP1-dependent dephosphorylation in these mechanisms. They provide a new target for the development of potential therapeutic treatment of neurodegeneration.
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Affiliation(s)
- Mélissa Farinelli
- Brain Research Institute, University of Zürich, Zürich, Switzerland
- Department of Biology, Swiss Federal Institute of Technology, Zürich, Zürich, Switzerland
| | - Fabrice D. Heitz
- Brain Research Institute, University of Zürich, Zürich, Switzerland
- Department of Biology, Swiss Federal Institute of Technology, Zürich, Zürich, Switzerland
| | | | - Shiva K. Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | - Fritjof Helmchen
- Brain Research Institute, University of Zürich, Zürich, Switzerland
| | - Isabelle M. Mansuy
- Brain Research Institute, University of Zürich, Zürich, Switzerland
- Department of Biology, Swiss Federal Institute of Technology, Zürich, Zürich, Switzerland
- * E-mail:
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Gross J, Angerstein M, Fuchs J, Stute K, Mazurek B. Expression analysis of prestin and selected transcription factors in newborn rats. Cell Mol Neurobiol 2011; 31:1089-101. [PMID: 21614551 DOI: 10.1007/s10571-011-9708-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 05/11/2011] [Indexed: 01/16/2023]
Abstract
Transcription factors (TFs) have a central role to play in regulating gene expression. To analyze the co-expression patterns of selected TFs with the motor protein prestin of the outer hair cells, we applied an real-time PCR approach combining several kinds of information: (i) expression changes during postnatal development, (ii) expression changes by exposure of organotypic cultures of the organ of Corti to factors which significantly affect prestin expression [thyroid hormone (T4), retinoic acid (RA), butyric acid (BA), increased KCl concentration] and (iii) changes along the apical-basal gradient. We found that the mRNA levels of the TF Brn-3c (Pou4f3), a member of the POU family, are significantly associated with the regulation of prestin during postnatal development and in cultures supplemented with T4 (0.5 μM), BA (0.5-2.0 mM), and high KCl (50 mM) concentration. The mRNA level of the constitutively active TF C/ebpb (CCAAT/enhancer binding protein beta) correlates positively with the prestin expression during postnatal development and in cultures exposed to T4 and RA (50-100 μM). The mRNA levels of the calcium-dependent TF CaRF correlates significantly with the prestin expression in cultures exposed to T4 and high KCl concentration. The observed coexpression patterns may suggest that the TFs Brn-3c, C/ebpb, and Carf contribute to regulating the expression of prestin under the investigated conditions.
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Affiliation(s)
- Johann Gross
- Molecular Biology Research Laboratory, Department of Otorhinolaryngology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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Virally delivered channelrhodopsin-2 safely and effectively restores visual function in multiple mouse models of blindness. Mol Ther 2011; 19:1220-9. [PMID: 21505421 DOI: 10.1038/mt.2011.69] [Citation(s) in RCA: 210] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Previous work established retinal expression of channelrhodopsin-2 (ChR2), an algal cation channel gated by light, restored physiological and behavioral visual responses in otherwise blind rd1 mice. However, a viable ChR2-based human therapy must meet several key criteria: (i) ChR2 expression must be targeted, robust, and long-term, (ii) ChR2 must provide long-term and continuous therapeutic efficacy, and (iii) both viral vector delivery and ChR2 expression must be safe. Here, we demonstrate the development of a clinically relevant therapy for late stage retinal degeneration using ChR2. We achieved specific and stable expression of ChR2 in ON bipolar cells using a recombinant adeno-associated viral vector (rAAV) packaged in a tyrosine-mutated capsid. Targeted expression led to ChR2-driven electrophysiological ON responses in postsynaptic retinal ganglion cells and significant improvement in visually guided behavior for multiple models of blindness up to 10 months postinjection. Light levels to elicit visually guided behavioral responses were within the physiological range of cone photoreceptors. Finally, chronic ChR2 expression was nontoxic, with transgene biodistribution limited to the eye. No measurable immune or inflammatory response was observed following intraocular vector administration. Together, these data indicate that virally delivered ChR2 can provide a viable and efficacious clinical therapy for photoreceptor disease-related blindness.
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Riquelme D, Alvarez A, Leal N, Adasme T, Espinoza I, Valdés JA, Troncoso N, Hartel S, Hidalgo J, Hidalgo C, Carrasco MA. High-frequency field stimulation of primary neurons enhances ryanodine receptor-mediated Ca2+ release and generates hydrogen peroxide, which jointly stimulate NF-κB activity. Antioxid Redox Signal 2011; 14:1245-59. [PMID: 20836702 DOI: 10.1089/ars.2010.3238] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neuronal electrical activity increases intracellular Ca(2+) concentration and generates reactive oxygen species. Here, we show that high frequency field stimulation of primary hippocampal neurons generated Ca(2+) signals with an early and a late component, and promoted hydrogen peroxide generation via a neuronal NADPH oxidase. Hydrogen peroxide generation required both Ca(2+) entry through N-methyl-D-aspartate receptors and Ca(2+) release mediated by ryanodine receptors (RyR). Field stimulation also enhanced nuclear translocation of the NF-κB p65 protein and NF-κB -dependent transcription, and increased c-fos mRNA and type-2 RyR protein content. Preincubation with inhibitory ryanodine or with the antioxidant N-acetyl L-cysteine abolished the increase in hydrogen peroxide generation and the late Ca(2+) signal component induced by electrical stimulation. Primary cortical cells behaved similarly as primary hippocampal cells. Exogenous hydrogen peroxide also activated NF-κB-dependent transcription in hippocampal neurons; inhibitory ryanodine prevented this effect. Selective inhibition of the NADPH oxidase or N-acetyl L-cysteine also prevented the enhanced translocation of p65 in hippocampal cells, while N-acetyl L-cysteine abolished the increase in RyR2 protein content induced by high frequency stimulation. In conclusion, the present results show that electrical stimulation induced reciprocal activation of ryanodine receptor-mediated Ca(2+) signals and hydrogen peroxide generation, which stimulated jointly NF-κB activity.
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Affiliation(s)
- Denise Riquelme
- Center of Molecular Studies of the Cell, Institute of Biomedical Sciences Programs, Universidad de Chile, Santiago, Chile
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Gouty-Colomer LA, Méry PF, Storme E, Gavois E, Robinson IC, Guérineau NC, Mollard P, Desarménien MG. Specific involvement of gonadal hormones in the functional maturation of growth hormone releasing hormone (GHRH) neurons. Endocrinology 2010; 151:5762-74. [PMID: 20926590 DOI: 10.1210/en.2010-0298] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Growth hormone (GH) is the key hormone involved in the regulation of growth and metabolism, two functions that are highly modulated during infancy. GH secretion, controlled mainly by GH releasing hormone (GHRH), has a characteristic pattern during postnatal development that results in peaks of blood concentration at birth and puberty. A detailed knowledge of the electrophysiology of the GHRH neurons is necessary to understand the mechanisms regulating postnatal GH secretion. Here, we describe the unique postnatal development of the electrophysiological properties of GHRH neurons and their regulation by gonadal hormones. Using GHRH-eGFP mice, we demonstrate that already at birth, GHRH neurons receive numerous synaptic inputs and fire large and fast action potentials (APs), consistent with effective GH secretion. Concomitant with the GH secretion peak occurring at puberty, these neurons display modifications of synaptic input properties, decrease in AP duration, and increase in a transient voltage-dependant potassium current. Furthermore, the modulation of both the AP duration and voltage-dependent potassium current are specifically controlled by gonadal hormones because gonadectomy prevented the maturation of these active properties and hormonal treatment restored it. Thus, GHRH neurons undergo specific developmental modulations of their electrical properties over the first six postnatal weeks, in accordance with hormonal demand. Our results highlight the importance of the interaction between the somatotrope and gonadotrope axes during the establishment of adapted neuroendocrine functions.
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Lu SG, Zhang XL, Luo DZ, Gold MS. Persistent inflammation alters the density and distribution of voltage-activated calcium channels in subpopulations of rat cutaneous DRG neurons. Pain 2010; 151:633-643. [PMID: 20884119 DOI: 10.1016/j.pain.2010.08.030] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 07/09/2010] [Accepted: 08/16/2010] [Indexed: 01/16/2023]
Abstract
The impact of persistent inflammation on voltage-activated Ca(2+) channels in cutaneous DRG neurons from adult rats was assessed with whole cell patch clamp techniques, sqRT-PCR and Western blot analysis. Inflammation was induced with a subcutaneous injection of complete Freund's adjuvant (CFA). DiI was used to identify DRG neurons innervating the site of inflammation. Three days after CFA injection, high threshold Ca(2+) current (HVA) density was significantly reduced in small and medium, but not large diameter neurons, reflecting a decrease in N-, L- and P/Q-type currents. This decrease in HVA current was associated with an increase in mRNA encoding the α2δ1-subunit complex, but no detectable change in N-type subunit (Ca(V)2.2) mRNA. An increase in both α2δ1 and Ca(V)2.2 protein was detected in the central nerves arising from L4 and L5 ganglia ipsilateral to the site of inflammation. In current clamp experiments on small and medium diameter cutaneous DRG neurons from naïve rats, blocking ∼40% of HVA current with Cd(2+) (5μM), had opposite effects on subpopulations of cutaneous DRG neurons (increasing excitability and action potential duration in some and decreasing excitability in others). The alterations in the density and distribution of voltage-activated Ca(2+) channels in subpopulations of cutaneous DRG neurons that develop following CFA injection should contribute to changes in sensory transmission observed in the presence of inflammation.
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Affiliation(s)
- Shao-Gang Lu
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh, Pittsburgh, PA 15213, USA Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA The Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA Department of Anesthesiology & Perioperative Care, School of Medicine, University of California, Irvine, CA 92697, USA
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Sun JJ, Kilb W, Luhmann HJ. Self-organization of repetitive spike patterns in developing neuronal networks in vitro. Eur J Neurosci 2010; 32:1289-99. [PMID: 20846326 DOI: 10.1111/j.1460-9568.2010.07383.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The appearance of spontaneous correlated activity is a fundamental feature of developing neuronal networks in vivo and in vitro. To elucidate whether the ontogeny of correlated activity is paralleled by the appearance of specific spike patterns we used a template-matching algorithm to detect repetitive spike patterns in multi-electrode array recordings from cultures of dissociated mouse neocortical neurons between 6 and 15 days in vitro (div). These experiments demonstrated that the number of spiking neurons increased significantly between 6 and 15 div, while a significantly synchronized network activity appeared at 9 div and became the main discharge pattern in the subsequent div. Repetitive spike patterns with a low complexity were first observed at 8 div. The number of repetitive spike patterns in each dataset as well as their complexity and recurrence increased during development in vitro. The number of links between neurons implicated in repetitive spike patterns, as well as their strength, showed a gradual increase during development. About 8% of the spike sequences contributed to more than one repetitive spike patterns and were classified as core patterns. These results demonstrate for the first time that defined neuronal assemblies, as represented by repetitive spike patterns, appear quite early during development in vitro, around the time synchronized network burst become the dominant network pattern. In summary, these findings suggest that dissociated neurons can self-organize into complex neuronal networks that allow reliable flow and processing of neuronal information already during early phases of development.
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Affiliation(s)
- Jyh-Jang Sun
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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Abstract
Recent experimental evidence suggests that coordinated expression of ion channels plays a role in constraining neuronal electrical activity. In particular, each neuronal cell type of the crustacean stomatogastric ganglion exhibits a unique set of positive linear correlations between ionic membrane conductances. These data suggest a causal relationship between expressed conductance correlations and features of cellular identity, namely electrical activity type. To test this idea, we used an existing database of conductance-based model neurons. We partitioned this database based on various measures of intrinsic activity, to approximate distinctions between biological cell types. We then tested individual conductance pairs for linear dependence to identify correlations. Contrary to experimental evidence, in which all conductance correlations are positive, 32% of correlations seen in this database were negative relationships. In addition, 80% of correlations seen here involved at least one calcium conductance, which have been difficult to measure experimentally. Similar to experimental results, each activity type investigated had a unique combination of correlated conductances. Finally, we found that populations of models that conform to a specific conductance correlation have a higher likelihood of exhibiting a particular feature of electrical activity. We conclude that regulating conductance ratios can support proper electrical activity of a wide range of cell types, particularly when the identity of the cell is well-defined by one or two features of its activity. Furthermore, we predict that previously unseen negative correlations and correlations involving calcium conductances are biologically plausible. Most motor neurons receive input from the brain before transmitting to the muscle, resulting in a muscle contraction. In some cases, a small group of motor neurons can act independently to control rhythmic muscle contractions. Locomotion in mammals is thought to arise, in a large part, due to neuronal networks of this type residing in the spinal cord. However, the cellular machinery that guarantees the needed rhythmic pattern of electrical activity in these neurons is not fully understood. Here, we use a small circuit that controls stomach contractions in crustaceans like crabs and lobsters, called the pyloric circuit, to investigate potential mechanisms for regulation of neuronal activity. Ion channel proteins are integral to determination of electrical activity type. Recently, experimental studies using cells of the pyloric circuit have shown correlations in the expression of these proteins. Our study uses a mathematical model of neuronal electrical activity to detail how these correlations may be influencing activity type. We found that correlations imposed on model parameters increase the likelihood of a desired behavior, and we therefore conclude that a biological cell utilizing ion-channel correlations will have the advantage of increased robustness of activity type.
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Olypher AV, Prinz AA. Geometry and dynamics of activity-dependent homeostatic regulation in neurons. J Comput Neurosci 2010; 28:361-74. [PMID: 20143143 PMCID: PMC2881194 DOI: 10.1007/s10827-010-0213-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 12/28/2009] [Accepted: 01/05/2010] [Indexed: 10/19/2022]
Abstract
To maintain activity in a functional range, neurons constantly adjust membrane excitability to changing intra- and extracellular conditions. Such activity-dependent homeostatic regulation (ADHR) is critical for normal processing of the nervous system and avoiding pathological conditions. Here, we posed a homeostatic regulation problem for the classical Morris-Lecar (ML) model. The problem was motivated by the phenomenon of the functional recovery of stomatogastric neurons in crustaceans in the absence of neuromodulation. In our study, the regulation of the ionic conductances in the ML model depended on the calcium current or the intracellular calcium concentration. We found an asymptotic solution to the problem under the assumption of slow regulation. The solution provides a full account of the regulation in the case of correlated or anticorrelated changes of the maximal conductances of the calcium and potassium currents. In particular, the solution shows how the target and parameters of the regulation determine which perturbations of the conductances can be compensated by the ADHR. In some cases, the sets of compensated initial perturbations are not convex. On the basis of our analysis we formulated specific questions for subsequent experimental and theoretical studies of ADHR.
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Affiliation(s)
- Andrey V. Olypher
- Biology Department, Emory University, 1510 Clifton Rd, Atlanta, GA 30322, USA,
| | - Astrid A. Prinz
- Biology Department, Emory University, 1510 Clifton Rd, Atlanta, GA 30322, USA,
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Harrill JA, Knapp GW, Crofton KM. Splice variant specific increase in Ca2+/calmodulin-dependent protein kinase 1-gamma mRNA expression in response to acute pyrethroid exposure. J Biochem Mol Toxicol 2010; 24:174-86. [PMID: 20143453 DOI: 10.1002/jbt.20324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In mammals, pyrethroids are neurotoxicants that interfere with ion channel function in excitable neuronal membranes. Previous work demonstrated increases in the expression of Ca(2+)/calmodulin-dependent protein kinase 1-gamma (Camk1g) mRNA following acute deltamethrin and permethrin exposure. In the rat, this gene is expressed as two distinct splice variants, Camk1g1 and Camk1g2. The present study tests the hypothesis that changes in Camk1g mRNA expression in the rat following acute pyrethroid exposure are due to a specific increase in the Camk1g1 splice variant and not the Camk1g2 splice variant. Long-Evans rats were acutely exposed to permethrin, deltamethrin, or corn oil vehicle. Frontal cortex was collected at 6 h postdosing. In addition, rats were exposed to permethrin (100 mg/kg) or deltamethrin (3 mg/kg), and frontal cortex was collected at 1, 3, 6, 9, 12, or 24 h along with time-matched vehicle controls. Expression of Camk1g1 and Camk1g2 mRNA was measured by quantitative real-time RT-PCR and quantified using the 2(-Delta Delta C)T method. Dose-dependent increases in Camk1g1 mRNA expression were observed for both pyrethroids at 6 h. In addition, a dose-dependent increase in Camk1g2 was observed at 6 h although it was very small in magnitude. The increases in Camk1g1 expression for deltamethrin and permethrin peak between 3 and 6 h postexposure and returns to control levels by 9 h. There was no increase in CAMK1G1 protein as measured with Western blots. The present data demonstrate that pyrethroid-induced changes in Camk1g are driven mainly by increased expression of the Camk1g1 splice variant.
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Affiliation(s)
- Joshua A Harrill
- Curriculum in Toxicology, University of North Carolina at Chapel Hill, CB 7270, Chapel Hill, NC 27599, USA.
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Mitochondrial Ca2+ cycling facilitates activation of the transcription factor NFAT in sensory neurons. J Neurosci 2009; 29:12101-14. [PMID: 19793968 DOI: 10.1523/jneurosci.3384-09.2009] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Ca(2+)-dependent gene regulation controls many aspects of neuronal plasticity. Significant progress has been made toward understanding the roles of voltage- and ligand-gated Ca(2+) channels in triggering specific transcriptional responses. In contrast, the functional importance of Ca(2+) buffers and Ca(2+) transporters in neuronal gene regulation is less clear despite their critical contribution to the spatiotemporal control of Ca(2+) signals. Here we examined the role of mitochondrial Ca(2+) uptake and release in regulating the Ca(2+)-dependent transcription factor NFAT (nuclear factor of activated T-cells), which has been implicated in synaptic plasticity, axonal growth, and neuronal survival. Intense stimulation of sensory neurons by action potentials or TRPV1 agonists induced rapid activation and nuclear import of NFAT. Nuclear translocation of NFAT was associated with a characteristic prolonged [Ca(2+)](i) elevation (plateau) that resulted from Ca(2+) uptake by, and its subsequent release from, mitochondria. Measurements using a mitochondrial Ca(2+) indicator, mtPericam, showed that this process recruited mitochondria throughout the cell body, including the perinuclear region. [Ca(2+)](i) levels attained during the plateau phase were similar to or higher than those required for NFAT activation (200-300 nm). The elimination of the [Ca(2+)](i) plateau by blocking either mitochondrial Ca(2+) uptake via the uniporter or Ca(2+) release via the mitochondrial Na(+)/Ca(2+) exchanger strongly reduced nuclear import of NFAT. Furthermore, preventing Ca(2+) mobilization via the mitochondrial Na(+)/Ca(2+) exchanger diminished NFAT-mediated transcription. Collectively, these data implicate activity-induced Ca(2+) uptake and prolonged release from mitochondria as a novel regulatory mechanism in neuronal excitation-transcription coupling.
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Sustained depolarization decreases calcium/calmodulin-dependent protein kinase II activity and gene expression in dopamine neurons. Neuroscience 2009; 163:277-85. [DOI: 10.1016/j.neuroscience.2009.06.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 06/15/2009] [Accepted: 06/17/2009] [Indexed: 11/24/2022]
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