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Chen AB, Duque M, Wang VM, Dhanasekar M, Mi X, Rymbek A, Tocquer L, Narayan S, Prober D, Yu G, Wyart C, Engert F, Ahrens MB. Norepinephrine changes behavioral state via astroglial purinergic signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.23.595576. [PMID: 38826423 PMCID: PMC11142163 DOI: 10.1101/2024.05.23.595576] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Both neurons and glia communicate via diffusible neuromodulatory substances, but the substrates of computation in such neuromodulatory networks are unclear. During behavioral transitions in the larval zebrafish, the neuromodulator norepinephrine drives fast excitation and delayed inhibition of behavior and circuit activity. We find that the inhibitory arm of this feedforward motif is implemented by astroglial purinergic signaling. Neuromodulator imaging, behavioral pharmacology, and perturbations of neurons and astroglia reveal that norepinephrine triggers astroglial release of adenosine triphosphate, extracellular conversion into adenosine, and behavioral suppression through activation of hindbrain neuronal adenosine receptors. This work, along with a companion piece by Lefton and colleagues demonstrating an analogous pathway mediating the effect of norepinephrine on synaptic connectivity in mice, identifies a computational and behavioral role for an evolutionarily conserved astroglial purinergic signaling axis in norepinephrine-mediated behavioral and brain state transitions.
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Affiliation(s)
- Alex B. Chen
- Janelia Research Campus, Howard Hughes Medical Institute; Ashburn, VA 20147, USA
- Department of Molecular and Cellular Biology, Harvard University; Cambridge, MA 02138, USA
- Graduate Program in Neuroscience, Harvard Medical School; Boston, MA 02115, USA
| | - Marc Duque
- Department of Molecular and Cellular Biology, Harvard University; Cambridge, MA 02138, USA
- Graduate Program in Neuroscience, Harvard Medical School; Boston, MA 02115, USA
| | - Vickie M. Wang
- Department of Molecular and Cellular Biology, Harvard University; Cambridge, MA 02138, USA
- Graduate Program in Neuroscience, Harvard Medical School; Boston, MA 02115, USA
| | - Mahalakshmi Dhanasekar
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique–Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Xuelong Mi
- Bradley Department of Electrical and Computer Engineering; Virginia Polytechnic Institute and State University; Arlington, VA 22203, USA
| | - Altyn Rymbek
- Tianqiao and Chrissy Chen Institute for Neuroscience, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Loeva Tocquer
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique–Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Sujatha Narayan
- Janelia Research Campus, Howard Hughes Medical Institute; Ashburn, VA 20147, USA
- Present address: Allen Institute for Neural Dynamics; Seattle, WA 98109, USA
| | - David Prober
- Tianqiao and Chrissy Chen Institute for Neuroscience, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Guoqiang Yu
- Department of Automation, Tsinghua University; Beijing 100084, P.R. China
| | - Claire Wyart
- Sorbonne Université, Paris Brain Institute (Institut du Cerveau, ICM), Institut National de la Santé et de la Recherche Médicale U1127, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Assistance Publique–Hôpitaux de Paris, Campus Hospitalier Pitié-Salpêtrière, Paris, France
| | - Florian Engert
- Department of Molecular and Cellular Biology, Harvard University; Cambridge, MA 02138, USA
| | - Misha B. Ahrens
- Janelia Research Campus, Howard Hughes Medical Institute; Ashburn, VA 20147, USA
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Marciante AB, Tadjalli A, Burrowes KA, Oberto JR, Luca EK, Seven YB, Nikodemova M, Watters JJ, Baker TL, Mitchell GS. Microglia regulate motor neuron plasticity via reciprocal fractalkine/adenosine signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592939. [PMID: 38765982 PMCID: PMC11100694 DOI: 10.1101/2024.05.07.592939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Microglia are innate CNS immune cells that play key roles in supporting key CNS functions including brain plasticity. We now report a previously unknown role for microglia in regulating neuroplasticity within spinal phrenic motor neurons, the neurons driving diaphragm contractions and breathing. We demonstrate that microglia regulate phrenic long-term facilitation (pLTF), a form of respiratory memory lasting hours after repetitive exposures to brief periods of low oxygen (acute intermittent hypoxia; AIH) via neuronal/microglial fractalkine signaling. AIH-induced pLTF is regulated by the balance between competing intracellular signaling cascades initiated by serotonin vs adenosine, respectively. Although brainstem raphe neurons release the relevant serotonin, the cellular source of adenosine is unknown. We tested a model in which hypoxia initiates fractalkine signaling between phrenic motor neurons and nearby microglia that triggers extracellular adenosine accumulation. With moderate AIH, phrenic motor neuron adenosine 2A receptor activation undermines serotonin-dominant pLTF; in contrast, severe AIH drives pLTF by a unique, adenosine-dominant mechanism. Phrenic motor neuron fractalkine knockdown, cervical spinal fractalkine receptor inhibition on nearby microglia, and microglial depletion enhance serotonin-dominant pLTF with moderate AIH but suppress adenosine-dominant pLTF with severe AIH. Thus, microglia play novel functions in the healthy spinal cord, regulating hypoxia-induced neuroplasticity within the motor neurons responsible for breathing.
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Affiliation(s)
- Alexandria B. Marciante
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Arash Tadjalli
- Current Address: Nova Southeastern University, College of Allopathic Medicine (NSU MD), Department of Medical Education, 3200 South University Drive, Fort Lauderdale, FL 33328-2018
| | - Kayla A. Burrowes
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Jose R. Oberto
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Edward K. Luca
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Yasin B. Seven
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Maria Nikodemova
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Jyoti J. Watters
- Current Address: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706
| | - Tracy L. Baker
- Current Address: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706
| | - Gordon S. Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
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Montalant A, Kiehn O, Perrier JF. Dopamine and noradrenaline activate spinal astrocyte endfeet via D1-like receptors. Eur J Neurosci 2024; 59:1278-1295. [PMID: 38052454 DOI: 10.1111/ejn.16205] [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: 09/08/2023] [Revised: 11/02/2023] [Accepted: 11/10/2023] [Indexed: 12/07/2023]
Abstract
Astrocytes, the most abundant glial cells in the central nervous system, respond to a wide variety of neurotransmitters binding to metabotropic receptors. Here, we investigated the intracellular calcium responses of spinal cord astrocytes to dopamine and noradrenaline, two catecholamines released by specific descending pathways. In a slice preparation from the spinal cord of neonatal mice, puff application of dopamine resulted in intracellular calcium responses that remained in the endfeet. Noradrenaline induced stronger responses that also started in the endfeet but spread to neighbouring compartments. The intracellular calcium responses were unaffected by blocking neuronal activity or inhibiting various neurotransmitter receptors, suggesting a direct effect of dopamine and noradrenaline on astrocytes. The intracellular calcium responses induced by noradrenaline and dopamine were inhibited by the D1 receptor antagonist SCH 23390. We assessed the functional consequences of these astrocytic responses by examining changes in arteriole diameter. Puff application of dopamine or noradrenaline resulted in vasoconstriction of spinal arterioles. However, blocking D1 receptors or manipulating astrocytic intracellular calcium levels did not abolish the vasoconstrictions, indicating that the observed intracellular calcium responses in astrocyte endfeet were not responsible for the vascular changes. Our findings demonstrate a compartmentalized response of spinal cord astrocytes to catecholamines and expand our understanding of astrocyte-neurotransmitter interactions and their potential roles in the physiology of the central nervous system.
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Affiliation(s)
- Alexia Montalant
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ole Kiehn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jean-François Perrier
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Onimaru H, Fukushi I, Ikeda K, Yazawa I, Takeda K, Okada Y, Izumizaki M. Cell Responses of the Ventrolateral Medulla to PAR1 Activation and Changes in Respiratory Rhythm in Newborn Rat En Bloc Brainstem-Spinal Cord Preparations. Neuroscience 2023; 528:89-101. [PMID: 37557948 DOI: 10.1016/j.neuroscience.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023]
Abstract
Proteinase-activated receptor-1 (PAR1) is expressed in astrocytes of various brain regions, and its activation is involved in the modulation of neuronal activity. Here, we report effects of PAR1 selective agonist TFLLR on respiratory rhythm generation in brainstem-spinal cord preparations. Preparations were isolated from newborn rats (P0-P4) under deep isoflurane anesthesia and were transversely cut at the rostral medulla. Preparations were superfused with artificial cerebrospinal fluid (25-26 °C), and inspiratory C4 ventral root activity was monitored. The responses to TFLLR of cells close to the cut surface were detected by calcium imaging or membrane potential recordings. Application of 10 μM TFLLR (4 min) induced a rapid and transient increase of calcium signal in cells of the ventrolateral respiratory regions of the medulla. More than 88% of responding cells (223/254 cells from 13 preparations) were also activated by low (0.2 mM) K+ solution, suggesting that they were astrocytes. Immunohistochemical examination demonstrated that PAR1 was expressed on many astrocytes. Respiratory-related neurons in the medulla were transiently hyperpolarized (-1.8 mV) during 10 μM TFLLR application, followed by weak membrane depolarization after washout. C4 burst rate decreased transiently in response to application of TFLLR, followed by a slight increase. The inhibitory effect was partially blocked by 50 μM theophylline. In conclusion, activation of astrocytes via PAR1 resulted in a decrease of inspiratory C4 burst rate in association with transient hyperpolarization of respiratory-related neurons. After washout, slow and weak excitatory responses appeared. Adenosine may be partially involved in the inhibitory effect of PAR1 activation.
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Affiliation(s)
- Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan.
| | - Isato Fukushi
- Faculty of Health Sciences, Aomori University of Health and Welfare, Aomori, Japan; Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Keiko Ikeda
- Department of Oral Physiology, Showa University School of Dentistry, Tokyo, Japan
| | - Itaru Yazawa
- Department of Food & Nutrition, Kyushu Nutrition Welfare University, Fukuoka, Japan
| | - Kotaro Takeda
- Faculty of Rehabilitation, School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Masahiko Izumizaki
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan
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5
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Marciante AB, Mitchell GS. Mild inflammation impairs acute intermittent hypoxia-induced phrenic long-term facilitation by a spinal adenosine-dependent mechanism. J Neurophysiol 2023; 129:799-806. [PMID: 36883762 PMCID: PMC10069977 DOI: 10.1152/jn.00035.2023] [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: 01/20/2023] [Revised: 02/23/2023] [Accepted: 02/23/2023] [Indexed: 03/09/2023] Open
Abstract
Inflammation undermines neuroplasticity, including serotonin-dependent phrenic long-term facilitation (pLTF) following moderate acute intermittent hypoxia (mAIH: 3, 5-min episodes, arterial Po2: 40-50 mmHg; 5-min intervals). Mild inflammation elicited by a low dose of the TLR-4 receptor agonist, lipopolysaccharide (LPS; 100 µg/kg, ip), abolishes mAIH-induced pLTF by unknown mechanisms. In the central nervous system, neuroinflammation primes glia, triggering ATP release and extracellular adenosine accumulation. As spinal adenosine 2 A (A2A) receptor activation impairs mAIH-induced pLTF, we hypothesized that spinal adenosine accumulation and A2A receptor activation are necessary in the mechanism whereby LPS impairs pLTF. We report that 24 h after LPS injection in adult male Sprague Dawley rats: 1) adenosine levels increase in ventral spinal segments containing the phrenic motor nucleus (C3-C5; P = 0.010; n = 7/group) and 2) cervical spinal A2A receptor inhibition (MSX-3, 10 µM, 12 µL intrathecal) rescues mAIH-induced pLTF. In LPS vehicle-treated rats (saline, ip), MSX-3 enhanced pLTF versus controls (LPS: 110 ± 16% baseline; controls: 53 ± 6%; P = 0.002; n = 6/group). In LPS-treated rats, pLTF was abolished as expected (4 ± 6% baseline; n = 6), but intrathecal MSX-3 restored pLTF to levels equivalent to MSX-3-treated control rats (120 ± 14% baseline; P < 0.001; n = 6; vs. LPS controls with MSX-3: P = 0.539). Thus, inflammation abolishes mAIH-induced pLTF by a mechanism that requires increased spinal adenosine levels and A2A receptor activation. As repetitive mAIH is emerging as a treatment to improve breathing and nonrespiratory movements in people with spinal cord injury or ALS, A2A inhibition may offset undermining effects of neuroinflammation associated with these neuromuscular disorders.NEW & NOTEWORTHY Mild inflammation undermines motor plasticity elicited by mAIH. In a model of mAIH-induced respiratory motor plasticity (phrenic long-term facilitation; pLTF), we report that inflammation induced by low-dose lipopolysaccharide undermines mAIH-induced pLTF by a mechanism requiring increased cervical spinal adenosine and adenosine 2 A receptor activation. This finding advances the understanding of mechanisms impairing neuroplasticity, potentially undermining the ability to compensate for the onset of lung/neural injury or to harness mAIH as a therapeutic modality.
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Affiliation(s)
- Alexandria B Marciante
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, Gainesville, Florida, United States
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy & McKnight Brain Institute, University of Florida, Gainesville, Florida, United States
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Broadhead MJ, Bonthron C, Waddington J, Smith WV, Lopez MF, Burley S, Valli J, Zhu F, Komiyama NH, Smith C, Grant SGN, Miles GB. Selective vulnerability of tripartite synapses in amyotrophic lateral sclerosis. Acta Neuropathol 2022; 143:471-486. [PMID: 35305541 PMCID: PMC8960590 DOI: 10.1007/s00401-022-02412-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/23/2022] [Accepted: 03/09/2022] [Indexed: 12/12/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder. Separate lines of evidence suggest that synapses and astrocytes play a role in the pathological mechanisms underlying ALS. Given that astrocytes make specialised contacts with some synapses, called tripartite synapses, we hypothesise that tripartite synapses could act as the fulcrum of disease in ALS. To test this hypothesis, we have performed an extensive microscopy-based investigation of synapses and tripartite synapses in the spinal cord of ALS model mice and post-mortem human tissue from ALS cases. We reveal widescale synaptic changes at the early symptomatic stages of the SOD1G93a mouse model. Super-resolution microscopy reveals that large complex postsynaptic structures are lost in ALS mice. Most surprisingly, tripartite synapses are selectively lost, while non-tripartite synapses remain in equal number to healthy controls. Finally, we also observe a similar selective loss of tripartite synapses in human post-mortem ALS spinal cords. From these data we conclude that tripartite synaptopathy is a key hallmark of ALS.
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Yazawa I, Okazaki S, Yokota S, Takeda K, Fukushi I, Yoshizawa M, Onimaru H, Okada Y. Coherence analysis of the calcium activity of putative astrocytic and neuronal cells on the L5 ventral horn and neural output in activated lumbar CPG networks. Neurosci Lett 2021; 771:136421. [PMID: 34968723 DOI: 10.1016/j.neulet.2021.136421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 12/03/2021] [Accepted: 12/22/2021] [Indexed: 11/18/2022]
Abstract
Astrocytes are thought to play a crucial role in providing structure to the spinal cord and maintaining efficient synaptic function and metabolism because their fine processes envelop the synapses of neurons and form many neuronal networks within the central nervous system (CNS). To investigate whether putative astrocytes and putative neurons distributed on the ventral horn play a role in the modulation of lumbar locomotor central pattern generator (CPG) networks, we used extracellular recording and optical imaging techniques and recorded the neural output from the left L5 ventral root and the calcium activity of putative astrocytes and neurons in the L5 ventral horn at the same time when activating an isolated L1-L5 spinal cord preparation from rats aged 0-2 days. Optical measurements detected cells that showed a fluorescence intensity change under all experimental conditions, namely, (1) 5-HT + NMDA, (2) TTX, and (3) TTX + Low K+. These cells were semiautomatically identified using an in-house MATLAB-based program, as putative astrocytes and neurons according to the cell classification, i.e., increased or decreased fluorescence intensity change (ΔF/F0), and subjective judgment based on their soma size. Coherence and its phase were calculated according to the calcium activity of the putative astrocytes and putative neurons, and neural output was calculated during fictive locomotion with in-house MATLAB-based programs. We found that the number of putative astrocytes activated by applying low K+ tends not to differ from that activated by applying the protease-activated receptor 1 (PAR1) selective agonist TFLLR-NH2 (TFLLR). Moreover, the calcium activity of several putative astrocytes and neurons synchronized with locomotor-like activity at a frequency range below 0.5 Hz and the time lag between peaks of cellular calcium activity and locomotor-like activity ranged from -1000 to + 1000 ms. These findings presumably indicates that these putative astrocytes and neurons in the left L5 ventral horn require -1000 to + 1000 ms to communicate with lumbar CPG networks and maintain efficient synaptic function and metabolism in activated lumbar CPG networks. This finding suggests the possibility that putative astrocytic and neuronal cells in the L5 ventral horn contribute to generating the rhythms and patterns of locomotor-like activity by activated CPG networks in the first to fifth lumbar spinal cord.
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Affiliation(s)
- Itaru Yazawa
- Global Research Center for Innovative Life Science, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Shinagawa, Tokyo 142-8501, Japan.
| | - Shuntaro Okazaki
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo 208-0011, Japan; Faculty of Human Sciences, Waseda University School of Human Sciences, Tokorozawa, Saitama 359-1192, Japan
| | - Shigefumi Yokota
- Department of Anatomy and Neurosciences, Shimane University School of Medicine, Izumo, Shimane 693-8501, Japan
| | - Kotaro Takeda
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo 208-0011, Japan; Faculty of Rehabilitation, Fujita Health University School of Healthcare, Toyoake, Aichi 470-1192, Japan
| | - Isato Fukushi
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo 208-0011, Japan; Faculty of Health Sciences, Uekusa Gakuen University, Chiba, Chiba 264-0007, Japan
| | - Masashi Yoshizawa
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo 208-0011, Japan; Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Shinagawa, Tokyo 142-8555, Japan
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo 208-0011, Japan
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8
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Orts-Del'Immagine A, Dhanasekar M, Lejeune FX, Roussel J, Wyart C. A norepinephrine-dependent glial calcium wave travels in the spinal cord upon acoustovestibular stimuli. Glia 2021; 70:491-507. [PMID: 34773299 DOI: 10.1002/glia.24118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/27/2021] [Accepted: 11/01/2021] [Indexed: 02/06/2023]
Abstract
Although calcium waves have been widely observed in glial cells, their occurrence in vivo during behavior remains less understood. Here, we investigated the recruitment of glial cells in the hindbrain and spinal cord after acousto-vestibular (AV) stimuli triggering escape responses using in vivo population calcium imaging in larval zebrafish. We observed that gap-junction-coupled spinal glial network exhibits large and homogenous calcium increases that rose in the rostral spinal cord and propagated bi-directionally toward the spinal cord and toward the hindbrain. Spinal glial calcium waves were driven by the recruitment of neurons and in particular, of noradrenergic signaling acting through α-adrenergic receptors. Noradrenergic neurons of the medulla-oblongata (NE-MO) were revealed in the vicinity of where the calcium wave started. NE-MO were recruited upon AV stimulation and sent dense axonal projections in the rostro-lateral spinal cord, suggesting these cells could trigger the glial wave to propagate down the spinal cord. Altogether, our results revealed that a simple AV stimulation is sufficient to recruit noradrenergic neurons in the brainstem that trigger in the rostral spinal cord two massive glial calcium waves, one traveling caudally in the spinal cord and another rostrally into the hindbrain.
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Affiliation(s)
| | | | | | | | - Claire Wyart
- Institut du cerveau, Sorbonne Université, Paris, France
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Montalant A, Carlsen EMM, Perrier J. Role of astrocytes in rhythmic motor activity. Physiol Rep 2021; 9:e15029. [PMID: 34558208 PMCID: PMC8461027 DOI: 10.14814/phy2.15029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 01/14/2023] Open
Abstract
Rhythmic motor activities such as breathing, locomotion, tremor, or mastication are organized by groups of interconnected neurons. Most synapses in the central nervous system are in close apposition with processes belonging to astrocytes. Neurotransmitters released from neurons bind to receptors expressed by astrocytes, activating a signaling pathway that leads to an increase in calcium concentration and the release of gliotransmitters that eventually modulate synaptic transmission. It is therefore likely that the activation of astrocytes impacts motor control. Here we review recent studies demonstrating that astrocytes inhibit, modulate, or trigger motor rhythmic behaviors.
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Affiliation(s)
- Alexia Montalant
- Department of NeuroscienceFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Eva M. M. Carlsen
- Department of NeuroscienceFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Jean‐François Perrier
- Department of NeuroscienceFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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10
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Broadhead MJ, Miles GB. A common role for astrocytes in rhythmic behaviours? Prog Neurobiol 2021; 202:102052. [PMID: 33894330 DOI: 10.1016/j.pneurobio.2021.102052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/03/2021] [Accepted: 04/13/2021] [Indexed: 01/16/2023]
Abstract
Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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11
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Böhme MA, McCarthy AW, Blaum N, Berezeckaja M, Ponimaskine K, Schwefel D, Walter AM. Glial Synaptobrevin mediates peripheral nerve insulation, neural metabolic supply, and is required for motor function. Glia 2021; 69:1897-1915. [PMID: 33811396 DOI: 10.1002/glia.24000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 01/10/2023]
Abstract
Peripheral nerves contain sensory and motor neuron axons coated by glial cells whose interplay ensures function, but molecular details are lacking. SNARE-proteins mediate the exchange and secretion of cargo by fusing vesicles with target organelles, but how glial SNAREs contribute to peripheral nerve function is largely unknown. We, here, identify non-neuronal Synaptobrevin (Syb) as the essential vesicular SNARE in Drosophila peripheral glia to insulate and metabolically supply neurons. We show that tetanus neurotoxin light chain (TeNT-LC), which potently inhibits SNARE-mediated exocytosis from neurons, also impairs peripheral nerve function when selectively expressed in glia, causing nerve disintegration, defective axonal transport, tetanic muscle hyperactivity, impaired locomotion, and lethality. While TeNT-LC disrupts neural function by cleaving neuronal Synaptobrevin (nSyb), it targets non-neuronal Synaptobrevin (Syb) in glia, which it cleaves at low rates: Glial knockdown of Syb (but not nSyb) phenocopied glial TeNT-LC expression whose effects were reverted by a TeNT-LC-insensitive Syb mutant. We link Syb-necessity to two distinct glial subtypes: Impairing Syb function in subperineurial glia disrupted nerve morphology, axonal transport, and locomotion, likely, because nerve-isolating septate junctions (SJs) could not form as essential SJ components (like the cell adhesion protein Neurexin-IV) were mistargeted. Interference with Syb in axon-encircling wrapping glia left nerve morphology and locomotion intact but impaired axonal transport, likely because neural metabolic supply was disrupted due to the mistargeting of metabolite shuffling monocarboxylate transporters. Our study identifies crucial roles of Syb in various glial subtypes to ensure glial-glial and glial-neural interplay needed for proper nerve function, animal motility, and survival.
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Affiliation(s)
- Mathias A Böhme
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany.,Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anthony W McCarthy
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - Natalie Blaum
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - Monika Berezeckaja
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - Kristina Ponimaskine
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - David Schwefel
- Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alexander M Walter
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany.,Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Taccola G, Salazar BH, Apicella R, Hogan MK, Horner PJ, Sayenko D. Selective Antagonism of A1 Adenosinergic Receptors Strengthens the Neuromodulation of the Sensorimotor Network During Epidural Spinal Stimulation. Front Syst Neurosci 2020; 14:44. [PMID: 32760254 PMCID: PMC7372902 DOI: 10.3389/fnsys.2020.00044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/16/2020] [Indexed: 01/02/2023] Open
Abstract
Although epidural spinal stimulation (ESS) results in promising therapeutic effects in individuals with spinal cord injury (SCI), its potential to generate functional motor recovery varies between individuals and remains largely unclear. However, both preclinical and clinical studies indicate the capacity of electrical and pharmacological interventions to synergistically increase the engagement of spinal sensorimotor networks and regain motor function after SCI. This study explored whether selective pharmacological antagonism of the adenosine A1 receptor subtype synergizes with ESS, thereby increasing motor response. We hypothesized that selective pharmacological antagonism of A1 receptors during ESS would produce facilitatory effects in spinal sensorimotor networks detected as an increased amplitude of spinally-evoked motor potentials and sustained duration of ESS induced activity. Terminal experiments were performed in adult rats using trains of stereotyped pulses at 40 Hz delivered at L5 with the local administration to the cord of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). We demonstrated that ESS combined with the blockage of A1 receptors increased the magnitude of the endogenous modulation and postponed the decay of responses that occur during ESS alone. Although DPCPX significantly increased the yield of repetitive stimulation in intact spinal cords, the effects of A1 antagonism on motor evoked responses after an acute spinal transection was not detected. These studies support the future investigation of the optimal dosage, methods of delivery, and systemic effects of the synergistic application of A1 antagonists and spinal stimulation in the intact and injured spinal cord.
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Affiliation(s)
- Giuliano Taccola
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Betsy Habeth Salazar
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Rosamaria Apicella
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Matthew Kevin Hogan
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Philip John Horner
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Dimitry Sayenko
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
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13
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Nanostructural Diversity of Synapses in the Mammalian Spinal Cord. Sci Rep 2020; 10:8189. [PMID: 32424125 PMCID: PMC7235094 DOI: 10.1038/s41598-020-64874-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/21/2020] [Indexed: 11/25/2022] Open
Abstract
Functionally distinct synapses exhibit diverse and complex organisation at molecular and nanoscale levels. Synaptic diversity may be dependent on developmental stage, anatomical locus and the neural circuit within which synapses reside. Furthermore, astrocytes, which align with pre and post-synaptic structures to form ‘tripartite synapses’, can modulate neural circuits and impact on synaptic organisation. In this study, we aimed to determine which factors impact the diversity of excitatory synapses throughout the lumbar spinal cord. We used PSD95-eGFP mice, to visualise excitatory postsynaptic densities (PSDs) using high-resolution and super-resolution microscopy. We reveal a detailed and quantitative map of the features of excitatory synapses in the lumbar spinal cord, detailing synaptic diversity that is dependent on developmental stage, anatomical region and whether associated with VGLUT1 or VGLUT2 terminals. We report that PSDs are nanostructurally distinct between spinal laminae and across age groups. PSDs receiving VGLUT1 inputs also show enhanced nanostructural complexity compared with those receiving VGLUT2 inputs, suggesting pathway-specific diversity. Finally, we show that PSDs exhibit greater nanostructural complexity when part of tripartite synapses, and we provide evidence that astrocytic activation enhances PSD95 expression. Taken together, these results provide novel insights into the regulation and diversification of synapses across functionally distinct spinal regions and advance our general understanding of the ‘rules’ governing synaptic nanostructural organisation.
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14
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Broadhead MJ, Miles GB. Bi-Directional Communication Between Neurons and Astrocytes Modulates Spinal Motor Circuits. Front Cell Neurosci 2020; 14:30. [PMID: 32180706 PMCID: PMC7057799 DOI: 10.3389/fncel.2020.00030] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/03/2020] [Indexed: 01/22/2023] Open
Abstract
Evidence suggests that astrocytes are not merely supportive cells in the nervous system but may actively participate in the control of neural circuits underlying cognition and behavior. In this study, we examined the role of astrocytes within the motor circuitry of the mammalian spinal cord. Pharmacogenetic manipulation of astrocytic activity in isolated spinal cord preparations obtained from neonatal mice revealed astrocyte-derived, adenosinergic modulation of the frequency of rhythmic output generated by the locomotor central pattern generator (CPG) network. Live Ca2+ imaging demonstrated increased activity in astrocytes during locomotor-related output and in response to the direct stimulation of spinal neurons. Finally, astrocytes were found to respond to neuronally-derived glutamate in a metabotropic glutamate receptor 5 (mGluR5) dependent manner, which in turn drives astrocytic modulation of the locomotor network. Our work identifies bi-directional signaling mechanisms between neurons and astrocytes underlying modulatory feedback control of motor circuits, which may act to constrain network output within optimal ranges for movement.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
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15
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Cortés A, Casadó-Anguera V, Moreno E, Casadó V. The heterotetrameric structure of the adenosine A 1-dopamine D 1 receptor complex: Pharmacological implication for restless legs syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:37-78. [PMID: 31229177 DOI: 10.1016/bs.apha.2019.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Dopaminergic and purinergic signaling play a pivotal role in neurological diseases associated with motor symptoms, including Parkinson's disease (PD), multiple sclerosis, amyotrophic lateral sclerosis, Huntington disease, Restless Legs Syndrome (RLS), spinal cord injury (SCI), and ataxias. Extracellular dopamine and adenosine exert their functions interacting with specific dopamine (DR) or adenosine (AR) receptors, respectively, expressed on the surface of target cells. These receptors are members of the family A of G protein-coupled receptors (GPCRs), which is the largest protein superfamily in mammalian genomes. GPCRs are target of about 40% of all current marketed drugs, highlighting their importance in clinical medicine. The striatum receives the densest dopamine innervations and contains the highest density of dopamine receptors. The modulatory role of adenosine on dopaminergic transmission depends largely on the existence of antagonistic interactions mediated by specific subtypes of DRs and ARs, the so-called A2AR-D2R and A1R-D1R interactions. Due to the dopamine/adenosine antagonism in the CNS, it was proposed that ARs and DRs could form heteromers in the neuronal cell surface. Therefore, adenosine can affect dopaminergic signaling through receptor-receptor interactions and by modulations in their shared intracellular pathways in the striatum and spinal cord. In this work we describe the allosteric modulations between GPCR protomers, focusing in those of adenosine and dopamine within the A1R-D1R heteromeric complex, which is involved in RLS. We also propose that the knowledge about the intricate allosteric interactions within the A1R-D1R heterotetramer, may facilitate the treatment of motor alterations, not only when the dopamine pathway is hyperactivated (RLS, chorea, etc.) but also when motor function is decreased (SCI, aging, PD, etc.).
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Affiliation(s)
- Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Verònica Casadó-Anguera
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Estefanía Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.
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16
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Rivera-Oliver M, Moreno E, Álvarez-Bagnarol Y, Ayala-Santiago C, Cruz-Reyes N, Molina-Castro GC, Clemens S, Canela EI, Ferré S, Casadó V, Díaz-Ríos M. Adenosine A 1-Dopamine D 1 Receptor Heteromers Control the Excitability of the Spinal Motoneuron. Mol Neurobiol 2018; 56:797-811. [PMID: 29797183 DOI: 10.1007/s12035-018-1120-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/11/2018] [Indexed: 10/16/2022]
Abstract
While the role of the ascending dopaminergic system in brain function and dysfunction has been a subject of extensive research, the role of the descending dopaminergic system in spinal cord function and dysfunction is just beginning to be understood. Adenosine plays a key role in the inhibitory control of the ascending dopaminergic system, largely dependent on functional complexes of specific subtypes of adenosine and dopamine receptors. Combining a selective destabilizing peptide strategy with a proximity ligation assay and patch-clamp electrophysiology in slices from male mouse lumbar spinal cord, the present study demonstrates the existence of adenosine A1-dopamine D1 receptor heteromers in the spinal motoneuron by which adenosine tonically inhibits D1 receptor-mediated signaling. A1-D1 receptor heteromers play a significant control of the motoneuron excitability, represent main targets for the excitatory effects of caffeine in the spinal cord and can constitute new targets for the pharmacological therapy after spinal cord injury, motor aging-associated disorders and restless legs syndrome.
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Affiliation(s)
- Marla Rivera-Oliver
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Estefanía Moreno
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Yocasta Álvarez-Bagnarol
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Christian Ayala-Santiago
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Nicole Cruz-Reyes
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Gian Carlo Molina-Castro
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Enric I Canela
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Sergi Ferré
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Technology Building, 333 Cassell Drive, Baltimore, MD, 21224, USA.
| | - Vicent Casadó
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Manuel Díaz-Ríos
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
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17
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Acton D, Broadhead MJ, Miles GB. Modulation of spinal motor networks by astrocyte-derived adenosine is dependent on D 1-like dopamine receptor signaling. J Neurophysiol 2018; 120:998-1009. [PMID: 29790837 PMCID: PMC6171060 DOI: 10.1152/jn.00783.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Astrocytes modulate many neuronal networks, including spinal networks responsible for the generation of locomotor behavior. Astrocytic modulation of spinal motor circuits involves release of ATP from astrocytes, hydrolysis of ATP to adenosine, and subsequent activation of neuronal A1 adenosine receptors (A1Rs). The net effect of this pathway is a reduction in the frequency of locomotor-related activity. Recently, it was proposed that A1Rs modulate burst frequency by blocking the D1-like dopamine receptor (D1LR) signaling pathway; however, adenosine also modulates ventral horn circuits by dopamine-independent pathways. Here, we demonstrate that adenosine produced upon astrocytic stimulation modulates locomotor-related activity by counteracting the excitatory effects of D1LR signaling and does not act by previously described dopamine-independent pathways. In spinal cord preparations from postnatal mice, a D1LR agonist, SKF 38393, increased the frequency of locomotor-related bursting induced by 5-hydroxytryptamine and N-methyl-d-aspartate. Bath-applied adenosine reduced burst frequency only in the presence of SKF 38393, as did adenosine produced after activation of protease-activated receptor-1 to stimulate astrocytes. Furthermore, the A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine enhanced burst frequency only in the presence of SKF 38393, indicating that endogenous adenosine produced by astrocytes during network activity also acts by modulating D1LR signaling. Finally, modulation of bursting by adenosine released upon stimulation of astrocytes was blocked by protein kinase inhibitor-(14-22) amide, a protein kinase A (PKA) inhibitor, consistent with A1R-mediated antagonism of the D1LR/adenylyl cyclase/PKA pathway. Together, these findings support a novel, astrocytic mechanism of metamodulation within the mammalian spinal cord, highlighting the complexity of the molecular interactions that specify motor output. NEW & NOTEWORTHY Astrocytes within the spinal cord produce adenosine during ongoing locomotor-related activity or when experimentally stimulated. Here, we show that adenosine derived from astrocytes acts at A1 receptors to inhibit a pathway by which D1-like receptors enhance the frequency of locomotor-related bursting. These data support a novel form of metamodulation within the mammalian spinal cord, enhancing our understanding of neuron-astrocyte interactions and their importance in shaping network activity.
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Affiliation(s)
- David Acton
- School of Psychology and Neuroscience, University of St Andrews , St Andrews , United Kingdom
| | - Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews , St Andrews , United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews , St Andrews , United Kingdom
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18
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Sebastião AM, Rei N, Ribeiro JA. Amyotrophic Lateral Sclerosis (ALS) and Adenosine Receptors. Front Pharmacol 2018; 9:267. [PMID: 29713276 PMCID: PMC5911503 DOI: 10.3389/fphar.2018.00267] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/09/2018] [Indexed: 12/11/2022] Open
Abstract
In the present review we discuss the potential involvement of adenosinergic signaling, in particular the role of adenosine receptors, in amyotrophic lateral sclerosis (ALS). Though the literature on this topic is not abundant, the information so far available on adenosine receptors in animal models of ALS highlights the interest to continue to explore the role of these receptors in this neurodegenerative disease. Indeed, all motor neurons affected in ALS are responsive to adenosine receptor ligands but interestingly, there are alterations in pre-symptomatic or early symptomatic stages that mirror those in advanced disease stages. Information starts to emerge pointing toward a beneficial role of A2A receptors (A2AR), most probably at early disease states, and a detrimental role of caffeine, in clear contrast with what occurs in other neurodegenerative diseases. However, some evidence also exists on a beneficial action of A2AR antagonists. It may happen that there are time windows where A2AR prove beneficial and others where their blockade is required. Furthermore, the same changes may not occur simultaneously at the different synapses. In line with this, it is not fully understood if ALS is a dying back disease or if it propagates in a centrifugal way. It thus seems crucial to understand how motor neuron dysfunction occurs, how adenosine receptors are involved in those dysfunctions and whether the early changes in purinergic signaling are compensatory or triggers for the disease. Getting this information is crucial before starting the design of purinergic based strategies to halt or delay disease progression.
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Affiliation(s)
- Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal
| | - Nádia Rei
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal
| | - Joaquim A Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal
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19
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Taccola G, Sayenko D, Gad P, Gerasimenko Y, Edgerton VR. And yet it moves: Recovery of volitional control after spinal cord injury. Prog Neurobiol 2017; 160:64-81. [PMID: 29102670 PMCID: PMC5773077 DOI: 10.1016/j.pneurobio.2017.10.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 10/09/2017] [Accepted: 10/21/2017] [Indexed: 12/12/2022]
Abstract
Preclinical and clinical neurophysiological and neurorehabilitation research has generated rather surprising levels of recovery of volitional sensory-motor function in persons with chronic motor paralysis following a spinal cord injury. The key factor in this recovery is largely activity-dependent plasticity of spinal and supraspinal networks. This key factor can be triggered by neuromodulation of these networks with electrical and pharmacological interventions. This review addresses some of the systems-level physiological mechanisms that might explain the effects of electrical modulation and how repetitive training facilitates the recovery of volitional motor control. In particular, we substantiate the hypotheses that: (1) in the majority of spinal lesions, a critical number and type of neurons in the region of the injury survive, but cannot conduct action potentials, and thus are electrically non-responsive; (2) these neuronal networks within the lesioned area can be neuromodulated to a transformed state of electrical competency; (3) these two factors enable the potential for extensive activity-dependent reorganization of neuronal networks in the spinal cord and brain, and (4) propriospinal networks play a critical role in driving this activity-dependent reorganization after injury. Real-time proprioceptive input to spinal networks provides the template for reorganization of spinal networks that play a leading role in the level of coordination of motor pools required to perform a given functional task. Repetitive exposure of multi-segmental sensory-motor networks to the dynamics of task-specific sensory input as occurs with repetitive training can functionally reshape spinal and supraspinal connectivity thus re-enabling one to perform complex motor tasks, even years post injury.
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Affiliation(s)
- G Taccola
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA; Neuroscience Department, International School for Advanced Studies (SISSA), Bonomea 265, Trieste, Italy
| | - D Sayenko
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - P Gad
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Y Gerasimenko
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA; Pavlov Institute of Physiology, St. Petersburg 199034, Russia
| | - V R Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA; Department of Neurobiology, University of California, Los Angeles, CA 90095 USA; Department of Neurosurgery, University of California, Los Angeles, CA 90095 USA; Brain Research Institute, University of California, Los Angeles, CA 90095 USA; The Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, 2007 NSW, Australia; Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Barcelona, 08916 Badalona, Spain.
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20
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Acton D, Miles GB. Gliotransmission and adenosinergic modulation: insights from mammalian spinal motor networks. J Neurophysiol 2017; 118:3311-3327. [PMID: 28954893 DOI: 10.1152/jn.00230.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Astrocytes are proposed to converse with neurons at tripartite synapses, detecting neurotransmitter release and responding with release of gliotransmitters, which in turn modulate synaptic strength and neuronal excitability. However, a paucity of evidence from behavioral studies calls into question the importance of gliotransmission for the operation of the nervous system in healthy animals. Central pattern generator (CPG) networks in the spinal cord and brain stem coordinate the activation of muscles during stereotyped activities such as locomotion, inspiration, and mastication and may therefore provide tractable models in which to assess the contribution of gliotransmission to behaviorally relevant neural activity. We review evidence for gliotransmission within spinal locomotor networks, including studies indicating that adenosine derived from astrocytes regulates the speed of locomotor activity via metamodulation of dopamine signaling.
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Affiliation(s)
- David Acton
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife , United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife , United Kingdom
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21
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Varani K, Vincenzi F, Merighi S, Gessi S, Borea PA. Biochemical and Pharmacological Role of A1 Adenosine Receptors and Their Modulation as Novel Therapeutic Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1051:193-232. [DOI: 10.1007/5584_2017_61] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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22
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van Waarde A, Dierckx RAJO, Zhou X, Khanapur S, Tsukada H, Ishiwata K, Luurtsema G, de Vries EFJ, Elsinga PH. Potential Therapeutic Applications of Adenosine A 2A Receptor Ligands and Opportunities for A 2A Receptor Imaging. Med Res Rev 2017; 38:5-56. [PMID: 28128443 DOI: 10.1002/med.21432] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 12/13/2022]
Abstract
Adenosine A2A receptors (A2A Rs) are highly expressed in the human striatum, and at lower densities in the cerebral cortex, the hippocampus, and cells of the immune system. Antagonists of these receptors are potentially useful for the treatment of motor fluctuations, epilepsy, postischemic brain damage, or cognitive impairment, and for the control of an immune checkpoint during immunotherapy of cancer. A2A R agonists may suppress transplant rejection and graft-versus-host disease; be used to treat inflammatory disorders such as asthma, inflammatory bowel disease, and rheumatoid arthritis; be locally applied to promote wound healing and be employed in a strategy for transient opening of the blood-brain barrier (BBB) so that therapeutic drugs and monoclonal antibodies can enter the brain. Increasing A2A R signaling in adipose tissue is also a potential strategy to combat obesity. Several radioligands for positron emission tomography (PET) imaging of A2A Rs have been developed in recent years. This review article presents a critical overview of the potential therapeutic applications of A2A R ligands, the use of A2A R imaging in drug development, and opportunities and limitations of PET imaging in future research.
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Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands.,Department of Nuclear Medicine, University Hospital, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Xiaoyun Zhou
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Shivashankar Khanapur
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Hideo Tsukada
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamakita, Hamamatsu, Shizuoka 434-8601, Japan
| | - Kiichi Ishiwata
- Research Institute of Cyclotron and Drug Discovery Research, Southern TOHOKU Research Institute for Neuroscience, 7-115 Yatsuyamada, Koriyama, 963-8052, Japan.,Department of Biofunctional Imaging, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.,Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Gert Luurtsema
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Erik F J de Vries
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Philip H Elsinga
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
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23
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Sámano C, Kaur J, Nistri A. A study of methylprednisolone neuroprotection against acute injury to the rat spinal cord in vitro. Neuroscience 2015; 315:136-49. [PMID: 26701292 DOI: 10.1016/j.neuroscience.2015.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 12/21/2022]
Abstract
Methylprednisolone sodium succinate (MPSS) has been proposed as a first-line treatment for acute spinal cord injury (SCI). Its clinical use remains, however, controversial because of the modest benefits and numerous side-effects. We investigated if MPSS could protect spinal neurons and glia using an in vitro model of the rat spinal cord that enables recording reflexes, fictive locomotion and morphological analysis of damage. With this model, a differential lesion affecting mainly either neurons or glia can be produced via kainate-evoked excitotoxicity or application of a pathological medium (lacking O2 and glucose), respectively. MPSS (6-10 μM) applied for 24 h after 1-h pathological medium protected astrocytes and oligodendrocytes especially in the ventrolateral white matter. This effect was accompanied by the return of slow, alternating oscillations (elicited by NMDA and 5-hydroxytryptamine (5-HT)) reminiscent of a sluggish fictive locomotor pattern. MPSS was, however, unable to reverse even a moderate neuronal loss and the concomitant suppression of fictive locomotion evoked by kainate (0.1 mM; 1 h). These results suggest that MPSS could, at least in part, contrast damage to spinal glia induced by a dysmetabolic state (associated to oxygen and glucose deprivation) and facilitate reactivation of spinal networks. Conversely, when even a minority of neurons was damaged by excitotoxicity, MPSS did not protect them nor did it restore network function in the current experimental model.
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Affiliation(s)
- C Sámano
- Departamento de Ciencias Naturales, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Mexico City, Mexico
| | - J Kaur
- Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy
| | - A Nistri
- Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy; SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory) Laboratory, Istituto di Medicina Fisica e Riabilitazione, Udine, Italy.
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Witts EC, Nascimento F, Miles GB. Adenosine-mediated modulation of ventral horn interneurons and spinal motoneurons in neonatal mice. J Neurophysiol 2015; 114:2305-15. [PMID: 26311185 PMCID: PMC4609759 DOI: 10.1152/jn.00574.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/21/2015] [Indexed: 01/20/2023] Open
Abstract
Neuromodulation allows neural networks to adapt to varying environmental and biomechanical demands. Purinergic signaling is known to be an important modulatory system in many parts of the CNS, including motor control circuitry. We have recently shown that adenosine modulates the output of mammalian spinal locomotor control circuitry (Witts EC, Panetta KM, Miles GB. J Neurophysiol 107: 1925–1934, 2012). Here we investigated the cellular mechanisms underlying this adenosine-mediated modulation. Whole cell patch-clamp recordings were performed on ventral horn interneurons and motoneurons within in vitro mouse spinal cord slice preparations. We found that adenosine hyperpolarized interneurons and reduced the frequency and amplitude of synaptic inputs to interneurons. Both effects were blocked by the A1-type adenosine receptor antagonist DPCPX. Analysis of miniature postsynaptic currents recorded from interneurons revealed that adenosine reduced their frequency but not amplitude, suggesting that adenosine acts on presynaptic receptors to modulate synaptic transmission. In contrast to interneurons, recordings from motoneurons revealed an adenosine-mediated depolarization. The frequency and amplitude of synaptic inputs to motoneurons were again reduced by adenosine, but we saw no effect on miniature postsynaptic currents. Again these effects on motoneurons were blocked by DPCPX. Taken together, these results demonstrate differential effects of adenosine, acting via A1 receptors, in the mouse spinal cord. Adenosine has a general inhibitory action on ventral horn interneurons while potentially maintaining motoneuron excitability. This may allow for adaptation of the locomotor pattern generated by interneuronal networks while helping to ensure the maintenance of overall motor output.
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Affiliation(s)
- Emily C Witts
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, United Kingdom
| | - Filipe Nascimento
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, United Kingdom
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