1
|
Lottes EN, Cox DN. Homeostatic Roles of the Proteostasis Network in Dendrites. Front Cell Neurosci 2020; 14:264. [PMID: 33013325 PMCID: PMC7461941 DOI: 10.3389/fncel.2020.00264] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular protein homeostasis, or proteostasis, is indispensable to the survival and function of all cells. Distinct from other cell types, neurons are long-lived, exhibiting architecturally complex and diverse multipolar projection morphologies that can span great distances. These properties present unique demands on proteostatic machinery to dynamically regulate the neuronal proteome in both space and time. Proteostasis is regulated by a distributed network of cellular processes, the proteostasis network (PN), which ensures precise control of protein synthesis, native conformational folding and maintenance, and protein turnover and degradation, collectively safeguarding proteome integrity both under homeostatic conditions and in the contexts of cellular stress, aging, and disease. Dendrites are equipped with distributed cellular machinery for protein synthesis and turnover, including dendritically trafficked ribosomes, chaperones, and autophagosomes. The PN can be subdivided into an adaptive network of three major functional pathways that synergistically govern protein quality control through the action of (1) protein synthesis machinery; (2) maintenance mechanisms including molecular chaperones involved in protein folding; and (3) degradative pathways (e.g., Ubiquitin-Proteasome System (UPS), endolysosomal pathway, and autophagy. Perturbations in any of the three arms of proteostasis can have dramatic effects on neurons, especially on their dendrites, which require tightly controlled homeostasis for proper development and maintenance. Moreover, the critical importance of the PN as a cell surveillance system against protein dyshomeostasis has been highlighted by extensive work demonstrating that the aggregation and/or failure to clear aggregated proteins figures centrally in many neurological disorders. While these studies demonstrate the relevance of derangements in proteostasis to human neurological disease, here we mainly review recent literature on homeostatic developmental roles the PN machinery plays in the establishment, maintenance, and plasticity of stable and dynamic dendritic arbors. Beyond basic housekeeping functions, we consider roles of PN machinery in protein quality control mechanisms linked to dendritic plasticity (e.g., dendritic spine remodeling during LTP); cell-type specificity; dendritic morphogenesis; and dendritic pruning.
Collapse
Affiliation(s)
| | - Daniel N. Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| |
Collapse
|
2
|
Abbaszadeh F, Fakhri S, Khan H. Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals. Pharmacol Res 2020; 160:105069. [PMID: 32652198 DOI: 10.1016/j.phrs.2020.105069] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/28/2020] [Accepted: 07/03/2020] [Indexed: 12/11/2022]
Abstract
Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.
Collapse
Affiliation(s)
- Fatemeh Abbaszadeh
- Department of Neuroscience, Faculty of Advanced Technologies in Medical Sciences, Iran University of Medical Sciences, Tehran, Iran; Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Fakhri
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran.
| | - Haroon Khan
- Department of Pharmacy, Abdul Wali Khan University Mardan, 23200, Pakistan.
| |
Collapse
|
3
|
Nasouti R, Khaksari M, Mirzaee M, Nazari-Robati M. Trehalose protects against spinal cord injury through regulating heat shock proteins 27 and 70 and caspase-3 genes expression. J Basic Clin Physiol Pharmacol 2019; 31:jbcpp-2018-0225. [PMID: 31586966 DOI: 10.1515/jbcpp-2018-0225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 08/11/2019] [Indexed: 12/30/2022]
Abstract
Background Heat shock proteins (HSPs) are a class of highly conserved proteins responsible for various functions critical to cell survival. Pharmacological induction of HSPs has been implicated in the regulation of neuronal loss and functional deficits in peripheral and central nervous system injuries. Accordingly, the present study was conducted to investigate the effect of trehalose on spinal expression of HSP27, HSP70 and caspase-3 genes following traumatic spinal cord injury (SCI) in rats. Methods Male rats weighing 250-300 g underwent laminectomy and were divided into four groups including sham, SCI (received SCI), vehicle (received SCI and phosphate buffer saline intrathecally) and trehalose (received 10 mM trehalose intrathecally following SCI). On days 1, 3 and 7 after injury, HSP27, HSP70 and caspase-3 genes transcripts were quantified in spinal cord tissues via a real-time PCR technique. In addition, locomotor function was assessed using the Basso, Beattie and Bresnahan (BBB) rating scale. Results SCI induced the expression of HSP27, HSP70 and caspase-3 genes and BBB score at all time points. Trehalose treatment upregulated HSP27, HSP70 genes expression at 1 day after SCI. Interestingly, a significant reduction in the expression of HSP27 and HSP70 genes was observed on days 3 and 7 following trauma compared with the vehicle group (p < 0.01). Caspase-3 gene showed a decrease in expression in the trehalose-treated group at all times. In addition, neurological function revealed an improvement after treatment with trehalose. Conclusion This study suggests that the neuroprotective effect of trehalose is mediated via regulation of HSP27 and HSP70, which are involved in cytoprotection and functional recovery following SCI.
Collapse
Affiliation(s)
- Roya Nasouti
- Department of Clinical Biochemistry, Afzalipour School of Medicine, Kerman University of Medical Sciences, 7616914115, Kerman, Iran.,Pharmaceutics Research Center, Kerman University of Medical Sciences, 7616914115, Kerman, Iran
| | - Mohammad Khaksari
- Endocrinology and Metabolism Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, 7616914115 Kerman, Iran
| | - Moghaddameh Mirzaee
- Department of Biostatistics and Epidemiology, School of Public Health, Kerman University of Medical Sciences, 7616914115 Kerman, Iran
| | - Mahdieh Nazari-Robati
- Department of Clinical Biochemistry, Afzalipour School of Medicine, Kerman University of Medical Sciences, 7616914115, Kerman, Iran.,Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, 7616914115 Kerman, Iran, Phone: +98-34-33257660, Fax: +98-34-33257448
| |
Collapse
|
4
|
Kim W, Kwon HJ, Jung HY, Yoo DY, Moon SM, Kim DW, Hwang IK. Tat-HSP70 protects neurons from oxidative damage in the NSC34 cells and ischemic damage in the ventral horn of rabbit spinal cord. Neurochem Int 2019; 129:104477. [PMID: 31145969 DOI: 10.1016/j.neuint.2019.104477] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/15/2019] [Accepted: 05/26/2019] [Indexed: 02/06/2023]
Abstract
Heat shock protein 70 (HSP70) is an ATP-dependent molecular chaperone, and it has been shown that its levels increase after exposure to various types of stress, including ischemia. In the present study, we investigated the effects of HSP70 against H2O2-induced neuronal stress in NSC34 cells and against spinal cord ischemia in rabbits. Tat-HSP70 proteins facilitated the intracellular delivery of HSP70 into the NSC34 cells and enabled them to cross the blood-brain barrier in the rabbit spinal cord. Tat-HSP70 was effectively transduced into NSC34 cells in a concentration- and time-dependent manner, while control-HSP70 protein could not be delivered intracellularly at any concentration or time after treatment. Treatment with Tat-HSP70 reduced the generation of reactive oxygen species and cell death induced by H2O2, while the control-HSP70 did not show any significant effect on the NSC34 cells exposed to H2O2. In rabbit spinal cord, the administration of Tat-HSP70 showed significant amelioration of neurological defects and neuronal death in the ventral horn of spinal cord. In addition, Tat-HSP70 treatment significantly reduced lipid peroxidation and increased Cu, Zn-superoxide dismutase activities in the spinal cord, but glutathione peroxidase and Mn-superoxide dismutase activities remained unchanged. These results suggest that Tat-HSP70, not control-HSP70, decreases cell damage by reducing oxidative stress in NSC34 cells and rabbit spinal cord, and it can be employed for the reduction of neuronal damage caused after spinal cord ischemia.
Collapse
Affiliation(s)
- Woosuk Kim
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Hyun Jung Kwon
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung, 25457, South Korea
| | - Hyo Young Jung
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Dae Young Yoo
- Department of Anatomy, College of Medicine, Soonchunhyang University, Cheonan, Chungcheongnam, 31151, South Korea
| | - Seung Myung Moon
- Department of Neurosurgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong, 18450, South Korea; Research Institute for Complementary & Alternative Medicine, Hallym University, Chuncheon, 24253, South Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung, 25457, South Korea.
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea.
| |
Collapse
|
5
|
Diaz A, Treviño S, Pulido-Fernandez G, Martínez-Muñoz E, Cervantes N, Espinosa B, Rojas K, Pérez-Severiano F, Montes S, Rubio-Osornio M, Jorge G. Epicatechin Reduces Spatial Memory Deficit Caused by Amyloid-β25⁻35 Toxicity Modifying the Heat Shock Proteins in the CA1 Region in the Hippocampus of Rats. Antioxidants (Basel) 2019; 8:antiox8050113. [PMID: 31052185 PMCID: PMC6562866 DOI: 10.3390/antiox8050113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/25/2019] [Accepted: 04/01/2019] [Indexed: 11/16/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by dementia and the aggregation of the amyloid beta peptide (Aβ). Aβ25-35 is the most neurotoxic sequence, whose mechanism is associated with the neuronal death in the Cornu Ammonis 1 (CA1) region of the hippocampus (Hp) and cognitive damage. Likewise, there are mechanisms of neuronal survival regulated by heat shock proteins (HSPs). Studies indicate that pharmacological treatment with flavonoids reduces the prevalence of AD, particularly epicatechin (EC), which shows better antioxidant activity. The aim of this work was to evaluate the effect of EC on neurotoxicity that causes Aβ25-35 at the level of spatial memory as well as the relationship with immunoreactivity of HSPs in the CA1 region of the Hp of rats. Our results show that EC treatment reduces the deterioration of spatial memory induced by the Aβ25-35, in addition to reducing oxidative stress and inflammation in the Hp of the animals treated with EC + Aβ25-35. Likewise, the immunoreactivity to HSP-60, -70, and -90 is lower in the EC + Aβ25-35 group compared to the Aβ25-35 group, which coincides with a decrease of dead neurons in the CA1 region of the Hp. Our results suggest that EC reduces the neurotoxicity induced by Aβ25-35, as well as the HSP-60, -70, and -90 immunoreactivity and neuronal death in the CA1 region of the Hp of rats injected with Aβ25-35, which favors an improvement in the function of spatial memory.
Collapse
Affiliation(s)
- Alfonso Diaz
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, Pue. PC. 72540, Mexico.
| | - Samuel Treviño
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, Pue. PC. 72540, Mexico.
| | - Guadalupe Pulido-Fernandez
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, Pue. PC. 72540, Mexico.
| | - Estefanía Martínez-Muñoz
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México PC. 04510, Mexico.
| | - Nallely Cervantes
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México PC. 04510, Mexico.
| | - Blanca Espinosa
- Departamento de Bioquímica, Instituto Nacional de Enfermedades Respiratorias, SSA, Ciudad de Mexico, PC. 14269, Mexico.
| | - Karla Rojas
- Departamento de Ciencias de la Salud, Psicologia. Universidad del Valle de México, sede Sur., Ciudad de Mexico, PC. 04910, Mexico.
| | - Francisca Pérez-Severiano
- Laboratorio de Neurofarmacología Molecular y Nanotecnología, Instituto Nacional de Neurología, SSA, Ciudad de Mexico, PC. 14269, Mexico.
| | - Sergio Montes
- Departamento de Neuroquímica, Instituto Nacional de Neurología, SSA, Ciudad de Mexico, PC. 14269, Mexico.
| | - Moises Rubio-Osornio
- Laboratorio Experimental de Enfermedades Neurodegenerarivas, SSA, Ciudad de Mexico, PC. 14269, Mexico.
| | - Guevara Jorge
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México PC. 04510, Mexico.
| |
Collapse
|
6
|
Wang C, Liu Y, Wang Y, Wei Z, Suo D, Ning G, Wu Q, Feng S, Wan C. Low‑frequency pulsed electromagnetic field promotes functional recovery, reduces inflammation and oxidative stress, and enhances HSP70 expression following spinal cord injury. Mol Med Rep 2019; 19:1687-1693. [PMID: 30628673 PMCID: PMC6390012 DOI: 10.3892/mmr.2019.9820] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 11/23/2018] [Indexed: 12/18/2022] Open
Abstract
Low-frequency pulsed electromagnetic fields (LPEMFs) have been reported to be protective for multiple diseases. However, whether the administration of LPEMFs inhibits inflammation and oxidative stress following spinal cord injury requires further investigation. In the current study, a contusion spinal cord injury model was used and LPEMFs administration was applied to investigate the molecular changes, including inflammation, oxidative stress and heat shock protein 70 (HSP70) levels. The results revealed that LPEMFs significantly promoted functional recovery following spinal cord injury, as demonstrated by an increased Basso, Beattie and Bresnahan score. The results demonstrated that LPEMFs decreased the expression of inflammatory factors, including tumor necrosis factor-α, interleukin-1β and nuclear factor-κB. Additionally, LPEMFs exposure reduced the levels of inducible nitric oxide synthase and reactive oxygen species, and upregulated the expression of catalase and superoxide dismutase. Furthermore, treatment with LPEMFs significantly enhanced the expression of HSP70 in spinal cord-injured rats. Overall, the present study revealed that LPEMFs promote functional recovery following spinal cord injury, potentially by modulating inflammation, oxidative stress and HSP70.
Collapse
Affiliation(s)
- Chunyan Wang
- Department of Rehabilitation Medicine, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Yang Liu
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Yao Wang
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Zhijian Wei
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Dongmei Suo
- Department of Rehabilitation Medicine, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Guangzhi Ning
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Qiuli Wu
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Shiqing Feng
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Chunxiao Wan
- Department of Rehabilitation Medicine, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| |
Collapse
|
7
|
Petrović A, Kaur J, Tomljanović I, Nistri A, Mladinic M. Pharmacological induction of Heat Shock Protein 70 by celastrol protects motoneurons from excitotoxicity in rat spinal cord in vitro. Eur J Neurosci 2018; 49:215-231. [PMID: 30362615 DOI: 10.1111/ejn.14218] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/14/2018] [Accepted: 10/15/2018] [Indexed: 12/29/2022]
Abstract
The secondary phase of spinal cord injury arising after the primary lesion largely extends the damage severity with delayed negative consequences for sensory-motor pathways. It is, therefore, important to find out if enhancing intrinsic mechanisms of neuroprotection can spare motoneurons that are very vulnerable cells. This issue was investigated with an in vitro model of rat spinal cord excitotoxicity monitored for up to 24 hr after the primary injury evoked by kainate. This study sought to pharmacologically boost the expression of heat shock proteins (HSP) to protect spinal motoneurons using celastrol to investigate if the rat spinal cord can upregulate HSP as neuroprotective mechanism. Despite its narrow range of drug safety in vitro, celastrol was not toxic to the rat spinal cord at 0.75 μM concentration and enhanced the expression of HSP70 by motoneurons. When celastrol was applied either before or after kainate, the number of dead motoneurons was significantly decreased and the nuclear localization of the cell death biomarker AIF strongly inhibited. Nevertheless, electrophysiological recording showed that protection of lumbar motor networks by celastrol was rather limited as reflex activity was impaired and fictive locomotion largely depressed, suggesting that functional deficit persisted, though the networks could express slow rhythmic oscillations. While our data do not exclude further recovery at later times beyond the experimental observations, the present results indicate that the upregulated expression of HSP in the aftermath of acute injury may be an interesting avenue for early protection of spinal motoneurons.
Collapse
Affiliation(s)
- Antonela Petrović
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia.,Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Jaspreet Kaur
- Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy
| | | | - Andrea Nistri
- Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Miranda Mladinic
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| |
Collapse
|
8
|
Ghezzi F, Monni L, Nistri A. Functional up-regulation of the M-current by retigabine contrasts hyperexcitability and excitotoxicity on rat hypoglossal motoneurons. J Physiol 2018; 596:2611-2629. [PMID: 29736957 DOI: 10.1113/jp275906] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/23/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Excessive neuronal excitability characterizes several neuropathological conditions, including neurodegenerative diseases such as amyotrophic lateral sclerosis. Hypoglossal motoneurons (HMs), which control tongue muscles, are extremely vulnerable to this disease and undergo damage and death when exposed to an excessive glutamate extracellular concentration that causes excitotoxicity. Our laboratory devised an in vitro model of excitotoxicity obtained by pharmacological blockade of glutamate transporters. In this paradigm, HMs display hyperexcitability, collective bursting and eventually cell death. The results of the present study show that pharmacological up-regulation of a K+ current (M-current), via application of the anti-convulsant retigabine, prevented all hallmarks of HM excitotoxicity, comprising bursting, generation of reactive oxygen species, expression of toxic markers and cell death. ○Our data may have translational value to develop new treatments against neurological diseases by using positive pharmacological modulators of the M-current. ABSTRACT Neuronal hyperexcitability is a symptom characterizing several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). In the ALS bulbar form, hypoglossal motoneurons (HMs) are an early target for neurodegeneration because of their high vulnerability to metabolic insults. In recent years, our laboratory has developed an in vitro model of a brainstem slice comprising the hypoglossal nucleus in which HM neurodegeneration is achieved by blocking glutamate clearance with dl-threo-β-benzyloxyaspartate (TBOA), thus leading to delayed excitotoxicity. During this process, HMs display a set of hallmarks such as hyperexcitability (and network bursting), reactive oxygen species (ROS) generation and, finally, cell death. The present study aimed to investigate whether blocking early hyperexcitability and bursting with the anti-convulsant drug retigabine was sufficient to achieve neuroprotection against excitotoxicity. Retigabine is a selective positive allosteric modulator of the M-current (IM ), an endogenous mechanism that neurons (comprising HMs) express to dampen excitability. Retigabine (10 μm; co-applied with TBOA) contrasted ROS generation, release of endogenous toxic factors into the HM cytoplasm and excitotoxicity-induced HM death. Electrophysiological experiments showed that retigabine readily contrasted and arrested bursting evoked by TBOA administration. Because neuronal IM subunits (Kv7.2, Kv7.3 and Kv7.5) were expressed in the hypoglossal nucleus and in functionally connected medullary nuclei, we suggest that they were responsible for the strong reduction in network excitability, a potent phenomenon for achieving neuroprotection against TBOA-induced excitotoxicity. The results of the present study may have translational value for testing novel positive pharmacological modulators of the IM under pathological conditions (including neurodegenerative disorders) characterized by excessive neuronal excitability.
Collapse
Affiliation(s)
- Filippo Ghezzi
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Laura Monni
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| |
Collapse
|
9
|
Monni L, Ghezzi F, Corsini S, Nistri A. Neurotoxicity of propofol on rat hypoglossal motoneurons in vitro. Neurosci Lett 2017; 655:95-100. [PMID: 28676256 DOI: 10.1016/j.neulet.2017.06.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/15/2017] [Accepted: 06/22/2017] [Indexed: 01/26/2023]
Abstract
Although propofol is a widely used intravenous general anaesthetic, many studies report its toxic potential, particularly on the developing central nervous system. We investigated its action on hypoglossal motoneurons (HMs) that control two critical functions in neonates, namely tongue muscle activity and airway patency. Thus, clinically relevant concentrations of propofol (1 and 5μM) were applied (4h) to neonatal rat brainstem slices to evaluate the expression of apoptosis-inducing factor (AIF) as biomarker of toxicity. This anaesthetic strongly increased AIF in the cytoplasm and the nucleus, without early loss of HMs. Electrophysiological recordings from HMs showed that propofol (5μM) enhanced GABA- and glycine-evoked current amplitude and lengthened GABAergic current decay time. Propofol also depressed NMDA receptor-mediated responses without affecting AMPA receptors. Since GABA and glycine depolarize neonatal HMs, we propose that the damaging action by propofol on these motoneurons might arise from the facilitated action of these transmitters with subsequent cytoplasmic Ca2+ overload. This phenomenon, in turn, may trigger cell death mechanisms manifested as increased expression of AIF and its translocation into the nucleus. Since propofol is also employed for induction and maintenance of paediatric surgery, caution is needed because its potential neurotoxicity might negatively impact neurodevelopment.
Collapse
Affiliation(s)
- Laura Monni
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Filippo Ghezzi
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Silvia Corsini
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), via Bonomea, 265, 34136 Trieste, Italy.
| |
Collapse
|
10
|
Corsini S, Tortora M, Rauti R, Nistri A. Nicotine protects rat hypoglossal motoneurons from excitotoxic death via downregulation of connexin 36. Cell Death Dis 2017; 8:e2881. [PMID: 28617431 PMCID: PMC5520892 DOI: 10.1038/cddis.2017.232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 04/21/2017] [Accepted: 04/26/2017] [Indexed: 01/01/2023]
Abstract
Motoneuron disease including amyotrophic lateral sclerosis may be due, at an early stage, to deficit in the extracellular clearance of the excitatory transmitter glutamate. A model of glutamate-mediated excitotoxic cell death based on pharmacological inhibition of its uptake was used to investigate how activation of neuronal nicotinic receptors by nicotine may protect motoneurons. Hypoglossal motoneurons (HMs) in neonatal rat brainstem slices were exposed to the glutamate uptake blocker DL-threo-β-benzyloxyaspartate (TBOA) that evoked large Ca2+ transients time locked among nearby HMs, whose number fell by about 30% 4 h later. As nicotine or the gap junction blocker carbenoxolone suppressed bursting, we studied connexin 36 (Cx36), which constitutes gap junctions in neurons and found it largely expressed by HMs. Cx36 was downregulated when nicotine or carbenoxolone was co-applied with TBOA. Expression of Cx36 was preferentially observed in cytosolic rather than membrane fractions after nicotine and TBOA, suggesting protein redistribution with no change in synthesis. Nicotine raised the expression of heat shock protein 70 (Hsp70), a protective factor that binds the apoptotic-inducing factor (AIF) whose nuclear translocation is a cause of cell death. TBOA increased intracellular AIF, an effect blocked by nicotine. These results indicate that activation of neuronal nicotinic receptors is an early tool for protecting motoneurons from excitotoxicity and that this process is carried out via the combined decrease in Cx36 activity, overexpression of Hsp70 and fall in AIF translocation. Thus, retarding or inhibiting HM death may be experimentally achieved by targeting one of these processes leading to motoneuron death.
Collapse
Affiliation(s)
- Silvia Corsini
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Maria Tortora
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Rossana Rauti
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| |
Collapse
|
11
|
Mazzone GL, Veeraraghavan P, Gonzalez-Inchauspe C, Nistri A, Uchitel OD. ASIC channel inhibition enhances excitotoxic neuronal death in an in vitro model of spinal cord injury. Neuroscience 2016; 343:398-410. [PMID: 28003157 DOI: 10.1016/j.neuroscience.2016.12.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/23/2016] [Accepted: 12/04/2016] [Indexed: 01/06/2023]
Abstract
In the spinal cord high extracellular glutamate evokes excitotoxic damage with neuronal loss and severe locomotor impairment. During the cell dysfunction process, extracellular pH becomes acid and may activate acid-sensing ion channels (ASICs) which could be important contributors to neurodegenerative pathologies. Our previous studies have shown that transient application of the glutamate analog kainate (KA) evokes delayed excitotoxic death of spinal neurons, while white matter is mainly spared. The present goal was to enquire if ASIC channels modulated KA damage in relation to locomotor network function and cell death. Mouse spinal cord slices were treated with KA (0.01 or 0.1mM) for 1h, and then washed out for 24h prior to analysis. RT-PCR results showed that KA (at 0.01mM concentration that is near-threshold for damage) increased mRNA expression of ASIC1a, ASIC1b, ASIC2 and ASIC3, an effect reversed by the ASIC inhibitor 4',6-diamidino-2-phenylindole (DAPI). A KA neurotoxic dose (0.1mM) reduced ASIC1a and ASIC2 expression. Cell viability assays demonstrated KA-induced large damage in spinal slices from mice with ASIC1a gene ablation. Likewise, immunohistochemistry indicated significant neuronal loss when KA was followed by the ASIC inhibitors DAPI or amiloride. Electrophysiological recording from ventral roots of isolated spinal cords showed that alternating oscillatory cycles were slowed down by 0.01mMKA, and intensely inhibited by subsequently applied DAPI or amiloride. Our data suggest that early rise in ASIC expression and function counteracted deleterious effects on spinal networks by raising the excitotoxicity threshold, a result with potential implications for improving neuroprotection.
Collapse
Affiliation(s)
- Graciela L Mazzone
- Laboratorios de Investigación aplicada en Neurociencias (LIAN) - Fundación para la Lucha conntra las Enfermedades Neurológicas de la Infancia (FLENI), CONICET, Buenos Aires, Argentina.
| | | | - Carlota Gonzalez-Inchauspe
- Instituto de Fisiología, Biología molecular y Neurociencias, CONICET, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Andrea Nistri
- Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy; Spinal Person Injury Neurorehabilitation Applied Laboratory (SPINAL), Istituto di Medicina Fisica e Riabilitazione, Udine, Italy
| | - Osvaldo D Uchitel
- Instituto de Fisiología, Biología molecular y Neurociencias, CONICET, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| |
Collapse
|
12
|
Delayed application of the anesthetic propofol contrasts the neurotoxic effects of kainate on rat organotypic spinal slice cultures. Neurotoxicology 2016; 54:1-10. [PMID: 26947011 DOI: 10.1016/j.neuro.2016.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/25/2016] [Accepted: 03/02/2016] [Indexed: 11/24/2022]
Abstract
Excitotoxicity due to hyperactivation of glutamate receptors is thought to underlie acute spinal injury with subsequent strong deficit in spinal network function. Devising an efficacious protocol of neuroprotection to arrest excitotoxicity might, therefore, spare a substantial number of neurons and allow later recovery. In vitro preparations of the spinal cord enable detailed measurement of spinal damage evoked by the potent glutamate analogue kainate. Any clinically-relevant neuroprotective treatment should start after the initial lesion and spare networks for at least 24h when cell damage plateaus. Using this strategy, we have observed that the gas anesthetic methoxyflurane provided strong, delayed neuroprotection. It is unclear if this beneficial effect was due to the mechanism of action by methoxyflurane, or it was the consequence of anesthetic depression. To test this hypothesis, we investigated the effect by propofol (commonly injected i.v. for general anesthesia) after kainate excitotoxicity induced on organotypic spinal slices. At 5μM concentration, propofol significantly attenuated cell death, including neuronal losses and, especially, damage to the highly vulnerable motoneurons. The action by propofol was fully prevented when co-applied with the GABAA antagonist bicuculline, indicating that neuroprotection required intact GABAA receptor function. Although bicuculline per se was not neurotoxic, it largely enhanced the lesional effects of kainate, suggesting that GABAA receptor activity could limit excitotoxicity. Our data might offer an explanation for the beneficial clinical outcome of neurosurgery performed as soon as possible after spinal lesion: we posit that general anesthesia contributes to this outcome, regardless of the type of anesthetic used.
Collapse
|