1
|
Aziz N, Ruzza C, Falcicchia C, Guarino A, Soukupova M, Asth L, Aleotti V, Bettegazzi B, Simonato M, Zucchini S. Lack of Direct Effects of Neurotrophic Factors in an In Vitro Model of Neuroinflammation. Int J Mol Sci 2024; 25:4160. [PMID: 38673746 PMCID: PMC11049901 DOI: 10.3390/ijms25084160] [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: 02/21/2024] [Revised: 03/26/2024] [Accepted: 03/30/2024] [Indexed: 04/28/2024] Open
Abstract
Neuroinflammation is associated with several neurological disorders including temporal lobe epilepsy. Seizures themselves can induce neuroinflammation. In an in vivo model of epilepsy, the supplementation of brain-derived neurotropic factor (BDNF) and fibroblast growth factor-2 (FGF-2) using a Herpes-based vector reduced epileptogenesis-associated neuroinflammation. The aim of this study was to test whether the attenuation of the neuroinflammation obtained in vivo with BDNF and FGF-2 was direct or secondary to other effects, for example, the reduction in the severity and frequency of spontaneous recurrent seizures. An in vitro model of neuroinflammation induced by lipopolysaccharide (LPS, 100 ng/mL) in a mouse primary mixed glial culture was used. The releases of cytokines and NO were analyzed via ELISA and Griess assay, respectively. The effects of LPS and neurotrophic factors on cell viability were determined by performing an MTT assay. BDNF and FGF-2 were tested alone and co-administered. LPS induced a significant increase in pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and NO. BDNF, FGF-2, and their co-administration did not counteract these LPS effects. Our study suggests that the anti-inflammatory effect of BDNF and FGF-2 in vivo in the epilepsy model was indirect and likely due to a reduction in seizure frequency and severity.
Collapse
Affiliation(s)
- Nimra Aziz
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
| | - Chiara Ruzza
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
- Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, 44121 Ferrara, Italy
| | | | - Annunziata Guarino
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
| | - Marie Soukupova
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
| | - Laila Asth
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
| | - Valentina Aleotti
- Operating Unit Neurological Clinic, University Hospital of Ferrara, via Aldo Moro 8, 44124 Ferrara, Italy;
| | - Barbara Bettegazzi
- School of Medicine, University Vita-Salute San Raffaele, via Olgettina 58, 20132 Milan, Italy;
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Michele Simonato
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Silvia Zucchini
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; (N.A.); (A.G.); (M.S.); (L.A.); (M.S.); (S.Z.)
- Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, 44121 Ferrara, Italy
| |
Collapse
|
2
|
Johnson SM, Gumnit MG, Johnson SM, Baker TL, Watters JJ. Disinhibition does not play a role in endomorphin-2-induced changes in inspiratory motoneuron output produced by in vitro neonatal rat preparations. Respir Physiol Neurobiol 2024; 320:104186. [PMID: 37944625 PMCID: PMC10843717 DOI: 10.1016/j.resp.2023.104186] [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: 08/09/2023] [Revised: 10/23/2023] [Accepted: 11/04/2023] [Indexed: 11/12/2023]
Abstract
Low level activation of mu-opioid receptors (MORs) in neonatal rat brainstem-spinal cord preparations increases inspiratory burst amplitude recorded on cervical spinal roots. We tested whether: (1) MOR activation with an endogenous ligand, such as endomorphin-2, increases inspiratory burst amplitude, (2) disinhibition of GABAergic or glycinergic inhibitory synaptic transmission is involved, and (3) inflammation alters endomorphin-2 effects. Using neonatal rat (P0-P3) brainstem-spinal cord preparations, bath-applied endomorphin-2 (10-200 nM) increased inspiratory burst amplitude and decreased burst frequency. Blockade of GABAA receptors (picrotoxin), glycine receptors (strychnine), or both (picrotoxin and strychnine) did not abolish endomorphin-2-induced effects. In preparations isolated from neonatal rats injected 3 h previously with lipopolysaccharide (LPS, 0.1 mg/kg), endomorphin-2 continued to decrease burst frequency but abolished the burst amplitude increase. Collectively, these data indicate that disinhibition of inhibitory synaptic transmission is unlikely to play a role in endomorphin-2-induced changes in inspiratory motor output, and that different mechanisms underlie the endomorphin-2-induced increases in inspiratory burst amplitude and decreases in burst frequency.
Collapse
Affiliation(s)
- Stephen M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
| | - Maia G Gumnit
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Sarah M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Tracy L Baker
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Jyoti J Watters
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| |
Collapse
|
3
|
Kumar P, Mathew S, Gamage R, Bodkin F, Doyle K, Rossetti I, Wagnon I, Zhou X, Raju R, Gyengesi E, Münch G. From the Bush to the Brain: Preclinical Stages of Ethnobotanical Anti-Inflammatory and Neuroprotective Drug Discovery-An Australian Example. Int J Mol Sci 2023; 24:11086. [PMID: 37446262 DOI: 10.3390/ijms241311086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023] Open
Abstract
The Australian rainforest is a rich source of medicinal plants that have evolved in the face of dramatic environmental challenges over a million years due to its prolonged geographical isolation from other continents. The rainforest consists of an inherent richness of plant secondary metabolites that are the most intense in the rainforest. The search for more potent and more bioavailable compounds from other plant sources is ongoing, and our short review will outline the pathways from the discovery of bioactive plants to the structural identification of active compounds, testing for potency, and then neuroprotection in a triculture system, and finally, the validation in an appropriate neuro-inflammatory mouse model, using some examples from our current research. We will focus on neuroinflammation as a potential treatment target for neurodegenerative diseases including multiple sclerosis (MS), Parkinson's (PD), and Alzheimer's disease (AD) for these plant-derived, anti-inflammatory molecules and highlight cytokine suppressive anti-inflammatory drugs (CSAIDs) as a better alternative to conventional nonsteroidal anti-inflammatory drugs (NSAIDs) to treat neuroinflammatory disorders.
Collapse
Affiliation(s)
- Payaal Kumar
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Shintu Mathew
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Rashmi Gamage
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Frances Bodkin
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Kerrie Doyle
- Indigenous Health Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Ilaria Rossetti
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Ingrid Wagnon
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Xian Zhou
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia
| | - Ritesh Raju
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Erika Gyengesi
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Gerald Münch
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia
| |
Collapse
|
4
|
Neuroinflammation microenvironment sharpens seizure circuit. Neurobiol Dis 2023; 178:106027. [PMID: 36736598 DOI: 10.1016/j.nbd.2023.106027] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
A large set of inflammatory molecules and their receptors are induced in epileptogenic foci of patients with pharmacoresistant epilepsies of structural etiologies or with refractory status epilepticus. Studies in animal models mimicking these clinical conditions have shown that the activation of specific inflammatory signallings in forebrain neurons or glial cells may modify seizure thresholds, thus contributing to both ictogenesis and epileptogenesis. The search for mechanisms underlying these effects has highlighted that inflammatory mediators have CNS-specific neuromodulatory functions, in addition to their canonical activation of immune responses for pathogen recognition and clearance. This review reports the neuromodulatory effects of inflammatory mediators and how they contribute to alter the inhibitory/excitatory balance in neural networks that underlie seizures. In particular, we describe key findings related to the ictogenic role of prototypical inflammatory cytokines (IL-1β and TNF) and danger signals (HMGB1), their modulatory effects of neuronal excitability, and the mechanisms underlying these effects. It will be discussed how harnessing these neuromodulatory properties of immune mediators may lead to novel therapies to control drug-resistant seizures.
Collapse
|
5
|
Cerovic M, Di Nunzio M, Craparotta I, Vezzani A. An in vitro model of drug-resistant seizures for selecting clinically effective antiseizure medications in Febrile Infection-Related Epilepsy Syndrome. Front Neurol 2023; 14:1129138. [PMID: 37034097 PMCID: PMC10074483 DOI: 10.3389/fneur.2023.1129138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/21/2023] [Indexed: 04/11/2023] Open
Abstract
Introduction FIRES is a rare epileptic encephalopathy induced by acute unremitting seizures that occur suddenly in healthy children or young adults after a febrile illness in the preceding 2 weeks. This condition results in high mortality, neurological disability, and drug-resistant epilepsy. The development of new therapeutics is hampered by the lack of validated experimental models. Our goal was to address this unmet need by providing a simple tool for rapid throughput screening of new therapies that target pathological inflammatory mechanisms in FIRES. The model was not intended to mimic the etiopathogenesis of FIRES which is still unknown, but to reproduce salient features of its clinical presentation such as the age, the cytokine storm and the refractoriness of epileptic activity to antiseizure medications (ASMs). Methods We refined an in vitro model of mouse hippocampal/temporal cortex acute slices where drug-resistant epileptic activity is induced by zero Mg2+/100 μM 4-aminopirydine. Clinical evidence suggests that acute unremitting seizures in FIRES are promoted by neuroinflammation triggered in the brain by the preceding infection. We mimicked this inflammatory component by exposing slices for 30 min to 10 μg/ml lipopolysaccharide (LPS). Results LPS induced a sustained neuroinflammatory response, as shown by increased mRNA levels of IL-1β, CXCL1 (IL-8), TNF, and increased IL-1β/IL-1Ra ratio. Epileptiform activity was exacerbated by neuroinflammation, also displaying increased resistance to maximal therapeutic concentrations of midazolam (100 μM), phenytoin (50 μM), sodium valproate (800 μM), and phenobarbital (100 μM). Treatment of LPS-exposed slices with two immunomodulatory drugs, a mouse anti-IL-6 receptor antibody (100 μM) corresponding to tocilizumab in humans, or anakinra (1.3 μM) which blocks the IL-1 receptor type 1, delayed the onset of epileptiform events and strongly reduced the ASM-resistant epileptiform activity evoked by neuroinflammation. These drugs were shown to reduce ASM-refractory seizures in FIRES patients. Discussion The neuroinflammatory component and the pharmacological responsiveness of epileptiform events provide a proof-of-concept validation of this in vitro model for the rapid selection of new treatments for acute ASM-refractory seizures in FIRES.
Collapse
Affiliation(s)
- Milica Cerovic
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
- *Correspondence: Milica Cerovic
| | - Martina Di Nunzio
- Department of Acute Brain Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Ilaria Craparotta
- Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Annamaria Vezzani
- Department of Acute Brain Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
- Annamaria Vezzani
| |
Collapse
|
6
|
Hikosaka M, Kawano T, Wada Y, Maeda T, Sakurai T, Ohtsuki G. Immune-Triggered Forms of Plasticity Across Brain Regions. Front Cell Neurosci 2022; 16:925493. [PMID: 35978857 PMCID: PMC9376917 DOI: 10.3389/fncel.2022.925493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/16/2022] [Indexed: 01/03/2023] Open
Abstract
Immune cells play numerous roles in the host defense against the invasion of microorganisms and pathogens, which induces the release of inflammatory mediators (e.g., cytokines and chemokines). In the CNS, microglia is the major resident immune cell. Recent efforts have revealed the diversity of the cell types and the heterogeneity of their functions. The refinement of the synapse structure was a hallmark feature of the microglia, while they are also involved in the myelination and capillary dynamics. Another promising feature is the modulation of the synaptic transmission as synaptic plasticity and the intrinsic excitability of neurons as non-synaptic plasticity. Those modulations of physiological properties of neurons are considered induced by both transient and chronic exposures to inflammatory mediators, which cause behavioral disorders seen in mental illness. It is plausible for astrocytes and pericytes other than microglia and macrophage to induce the immune-triggered plasticity of neurons. However, current understanding has yet achieved to unveil what inflammatory mediators from what immune cells or glia induce a form of plasticity modulating pre-, post-synaptic functions and intrinsic excitability of neurons. It is still unclear what ion channels and intracellular signaling of what types of neurons in which brain regions of the CNS are involved. In this review, we introduce the ubiquitous modulation of the synaptic efficacy and the intrinsic excitability across the brain by immune cells and related inflammatory cytokines with the mechanism for induction. Specifically, we compare neuro-modulation mechanisms by microglia of the intrinsic excitability of cerebellar Purkinje neurons with cerebral pyramidal neurons, stressing the inverted directionality of the plasticity. We also discuss the suppression and augmentation of the extent of plasticity by inflammatory mediators, as the meta-plasticity by immunity. Lastly, we sum up forms of immune-triggered plasticity in the different brain regions with disease relevance. Together, brain immunity influences our cognition, sense, memory, and behavior via immune-triggered plasticity.
Collapse
Affiliation(s)
| | | | | | | | | | - Gen Ohtsuki
- Department of Drug Discovery Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| |
Collapse
|
7
|
Zhang L, Li S, Tai Z, Yu C, Xu Z. Gut Microbes Regulate Innate Immunity and Epilepsy. Front Neurosci 2022; 16:870197. [PMID: 35720723 PMCID: PMC9198293 DOI: 10.3389/fnins.2022.870197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 04/13/2022] [Indexed: 12/03/2022] Open
Abstract
Epilepsy is a common chronic brain disease. There are many clinical methods to control epileptic seizures, such as anti-seizure medications (ASMs) or surgical removal of epileptogenic lesions. However, the pathophysiology of epilepsy is still unknown, making it difficult to control or prevent it. The host’s immune system monitors gut microbes, interacts with microbes through pattern recognition receptors such as Toll-like receptors (TLRs) and NOD-like receptors (NLRs) expressed by innate immune cells, and activates immune responses in the body to kill pathogens and balance the relationship between microbes and host. In addition, inflammatory responses induced by the innate immune system are seen in animal models of epilepsy and temporal lobe epilepsy brain tissue to combat pathogens or injuries. This review summarizes the potential relationship between gut microbes, innate immunity, and epilepsy based on recent research to provide more hints for researchers to explore this field further.
Collapse
Affiliation(s)
- Linhai Zhang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Shuang Li
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Zhenzhen Tai
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Changyin Yu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Zucai Xu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| |
Collapse
|
8
|
Systemic Administration of Lipopolysaccharide Induces Hyperexcitability of Prelimbic Neurons via modulation of Sodium and Potassium Currents. Neurotoxicology 2022; 91:128-139. [DOI: 10.1016/j.neuro.2022.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/18/2022]
|
9
|
Yamawaki Y, Wada Y, Matsui S, Ohtsuki G. Microglia-triggered hypoexcitability plasticity of pyramidal neurons in the rat medial prefrontal cortex. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100028. [DOI: 10.1016/j.crneur.2022.100028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 01/14/2022] [Accepted: 01/30/2022] [Indexed: 12/16/2022] Open
|
10
|
Jiang Q, Li C, Zeng W, Xu H, Li J, Zhang T, Deng G, Wang Y. Inhibition of Connexin 36 attenuates HMGB1-mediated depressive-like behaviors induced by chronic unpredictable mild stress. Brain Behav 2022; 12:e2470. [PMID: 35089644 PMCID: PMC8865165 DOI: 10.1002/brb3.2470] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/30/2021] [Accepted: 12/08/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND High mobility group box 1 (HMGB1) released by neurons and microglia was demonstrated to be an important mediator in depressive-like behaviors induced by chronic unpredictable mild stress (CUMS), which could lead to the imbalance of two different metabolic approaches in kynurenine pathway (KP), thus enhancing glutamate transmission and exacerbating depressive-like behaviors. Evidence showed that HMGB1 signaling might be regulated by Connexin (Cx) 36 in inflammatory diseases of central nervous system (CNS). Our study aimed to further explore the role of Cx36 in depressive-like behaviors and its relationship with HMGB1. METHODS After 4-week chronic stress, behavioral tests were conducted to evaluate depressive-like behaviors, including sucrose preference test (SPT), tail suspension test (TST), forced swimming test (FST), and open field test (OFT). Western blot analysis and immunofluorescence staining were used to observe the expression and location of Cx36. Enzyme-linked immunosorbent assay (ELISA) was adopted to detect the concentrations of inflammatory cytokines. And the excitability and inward currents of hippocampal neurons were recorded by whole-cell patch clamping. RESULTS The expression of Cx36 was significantly increased in hippocampal neurons of mice exposed to CUMS, while treatment with glycyrrhizinic acid (GZA) or quinine could both down-regulate Cx36 and alleviate depressive-like behaviors. The proinflammatory cytokines like HMGB1, tumor necrosis factor alpha (TNF-α), and interleukin-1β (IL-1β) were all elevated by CUMS, and application of GZA and quinine could decrease them. In addition, the enhanced excitability and inward currents of hippocampal neurons induced by lipopolysaccharide (LPS) could be reduced by either GZA or quinine. CONCLUSIONS Inhibition of Cx36 in hippocampal neurons might attenuates HMGB1-mediated depressive-like behaviors induced by CUMS through down-regulation of the proinflammatory cytokines and reduction of the excitability and intracellular ion overload.
Collapse
Affiliation(s)
- Qian Jiang
- Department of PsychiatryFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Chao‐Ran Li
- Department of Nautical PsychologyFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Wen‐Feng Zeng
- Department of Nautical PsychologyFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Hui‐Jing Xu
- Department of PsychiatryFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Jia‐Mei Li
- Department of Stress MedicineFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Ting Zhang
- Department of Nautical PsychologyFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Guang‐Hui Deng
- Department of PsychiatryFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| | - Yun‐Xia Wang
- Department of Nautical PsychologyFaculty of PsychologySecond Military Medical UniversityShanghaiP. R. China
| |
Collapse
|
11
|
Lipopolysaccharide-induced neuroinflammation disrupts functional connectivity and community structure in primary cortical microtissues. Sci Rep 2021; 11:22303. [PMID: 34785714 PMCID: PMC8595892 DOI: 10.1038/s41598-021-01616-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/29/2021] [Indexed: 12/15/2022] Open
Abstract
Three-dimensional (3D) neural microtissues are a powerful in vitro paradigm for studying brain development and disease under controlled conditions, while maintaining many key attributes of the in vivo environment. Here, we used primary cortical microtissues to study the effects of neuroinflammation on neural microcircuits. We demonstrated the use of a genetically encoded calcium indicator combined with a novel live-imaging platform to record spontaneous calcium transients in microtissues from day 14-34 in vitro. We implemented graph theory analysis of calcium activity to characterize underlying functional connectivity and community structure of microcircuits, which are capable of capturing subtle changes in network dynamics during early disease states. We found that microtissues cultured for 34 days displayed functional remodeling of microcircuits and that community structure strengthened over time. Lipopolysaccharide, a neuroinflammatory agent, significantly increased functional connectivity and disrupted community structure 5-9 days after exposure. These microcircuit-level changes have broad implications for the role of neuroinflammation in functional dysregulation of neural networks.
Collapse
|
12
|
Segawa K, Blumenthal Y, Yamawaki Y, Ohtsuki G. A Destruction Model of the Vascular and Lymphatic Systems in the Emergence of Psychiatric Symptoms. BIOLOGY 2021; 10:34. [PMID: 33419067 PMCID: PMC7825436 DOI: 10.3390/biology10010034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/24/2020] [Accepted: 12/31/2020] [Indexed: 01/02/2023]
Abstract
The lymphatic system is important for antigen presentation and immune surveillance. The lymphatic system in the brain was originally introduced by Giovanni Mascagni in 1787, while the rediscovery of it by Jonathan Kipnis and Kari Kustaa Alitalo now opens the door for a new interpretation of neurological diseases and therapeutic applications. The glymphatic system for the exchanges of cerebrospinal fluid (CSF) and interstitial fluid (ISF) is associated with the blood-brain barrier (BBB), which is involved in the maintenance of immune privilege and homeostasis in the brain. Recent notions from studies of postmortem brains and clinical studies of neurodegenerative diseases, infection, and cerebral hemorrhage, implied that the breakdown of those barrier systems and infiltration of activated immune cells disrupt the function of both neurons and glia in the parenchyma (e.g., modulation of neurophysiological properties and maturation of myelination), which causes the abnormality in the functional connectivity of the entire brain network. Due to the vulnerability, such dysfunction may occur in developing brains as well as in senile or neurodegenerative diseases and may raise the risk of emergence of psychosis symptoms. Here, we introduce this hypothesis with a series of studies and cellular mechanisms.
Collapse
Affiliation(s)
- Kohei Segawa
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8397, Japan; (K.S.); (Y.Y.)
| | - Yukari Blumenthal
- Urology Department at Cambridge University Hospitals, NHS Foundation Trust, Addenbrooke’s Hospital, Hills Road Cambridge, Cambridge CB2 0QQ, UK;
| | - Yuki Yamawaki
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8397, Japan; (K.S.); (Y.Y.)
| | - Gen Ohtsuki
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8397, Japan; (K.S.); (Y.Y.)
| |
Collapse
|
13
|
Zheng ZH, Tu JL, Li XH, Hua Q, Liu WZ, Liu Y, Pan BX, Hu P, Zhang WH. Neuroinflammation induces anxiety- and depressive-like behavior by modulating neuronal plasticity in the basolateral amygdala. Brain Behav Immun 2021; 91:505-518. [PMID: 33161163 DOI: 10.1016/j.bbi.2020.11.007] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/22/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Increasing evidence indicates that excessive inflammatory responses play a crucial role in the pathophysiology of psychiatric diseases, including depression and anxiety disorders. The dysfunctional neural plasticity in amygdala has long been proposed as the vital cause for the progression of psychiatric disorders. However, the effect of neuroinflammation on the functional changes of the amygdala remains largely unknown. Here, by using a mouse model of inflammation induced by lipopolysaccharide (LPS) injection, we investigated the effect of LPS-induced neuroinflammation on the synaptic and non-synaptic plasticity in basolateral amygdala (BLA) projection neurons (PNs) and their contribution to the LPS-induced anxiety- and depressive-like behavior. The results showed that LPS treatment led to the activation of microglia and production of proinflammatory cytokines in the BLA. Furthermore, LPS treatment increased excitatory but not inhibitory synaptic transmission due to the enhanced presynaptic glutamate release, thus leading to the shift of excitatory/inhibitory balance towards excitatory. In addition, the intrinsic neuronal excitability of BLA PNs was also increased by LPS treatment through the loss of expression and function of small-conductance, calcium-activated potassium channel. Chronic fluoxetine pretreatment significantly prevented these neurophysiological changes induced by LPS, and alleviated anxiety and depressive-like behavior, indicating that LPS-induced neuronal dysregulation of BLA PNs may contribute to the development of psychiatry disorders. Collectively, these findings provide evidence that dysregulation of synaptic and non-synaptic transmission in the BLA PNs may account for neuroinflammation-induced anxiety- and depressive-like behavior.
Collapse
Affiliation(s)
- Zhi-Heng Zheng
- Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang 330031, PR China
| | - Jiang-Long Tu
- Department of Neurology, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, PR China
| | - Xiao-Han Li
- Department of Clinic Medicine, School of Queen Mary, Nanchang University, Nanchang, PR China
| | - Qing Hua
- Department of Clinic Medicine, School of Queen Mary, Nanchang University, Nanchang, PR China
| | - Wei-Zhu Liu
- Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang 330031, PR China
| | - Yu Liu
- Rehabilitation Department, Second Affiliated Hospital of Nanchang University, PR China
| | - Bing-Xing Pan
- Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang 330031, PR China
| | - Ping Hu
- Institute of Translational Medicine, Nanchang University, Nanchang 330001, PR China
| | - Wen-Hua Zhang
- Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang 330031, PR China.
| |
Collapse
|
14
|
Metformin Ameliorates Lipopolysaccharide-Induced Depressive-Like Behaviors and Abnormal Glutamatergic Transmission. BIOLOGY 2020; 9:biology9110359. [PMID: 33114529 PMCID: PMC7692296 DOI: 10.3390/biology9110359] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/28/2022]
Abstract
Simple Summary Metformin is a promising drug for diabetes and has been reported to have antidepressant effects in depression patients or patients with comorbid depression and other diseases. However, it is largely unclear how metformin ameliorates depressive-like behaviors. To this end, we injected mice with a bacterial endotoxin (lipopolysaccharide) to induce depressive-like behaviors such as increased immobility in the forced swimming test and tail suspension test. In this depression mouse model, metformin administration ameliorated depressive-like behaviors. Glutamate is a major excitatory signal for the communications between neurons in the brain. Dysfunction of glutamatergic neurotransmission is implicated in the pathogenesis of depression. Glutamatergic transmission was elevated in our depression mouse model. Metformin administration also recovered the glutamatergic transmission deficit in the model. Taken together, our results suggest metformin had antidepressant effects and can correct abnormal glutamatergic transmission in the lipopolysaccharide-induced depression mouse model. These findings provide new insights into the underlying mechanism by which metformin acts against depression. Abstract Metformin, a first-line drug for type 2 diabetes mellitus (T2DM), has been found to reduce depressive symptoms in patients with comorbid depression and other diseases. However, it is largely unclear how metformin ameliorates depressive-like behaviors. Here, we used lipopolysaccharide (LPS) to induce depressive-like behaviors in mice and found that LPS-treated mice exhibited increased immobility in the forced swimming test (FST) and tail suspension test (TST), as well as increased glutamatergic transmission. Furthermore, metformin administration in the LPS-treated mice ameliorated depressive-like behaviors and elevated glutamatergic transmission. Our results suggest that metformin has antidepressant effects and can correct abnormal glutamatergic transmission, providing an insight into the underlying mechanism by which metformin acts against depression.
Collapse
|
15
|
Serial Systemic Injections of Endotoxin (LPS) Elicit Neuroprotective Spinal Cord Microglia through IL-1-Dependent Cross Talk with Endothelial Cells. J Neurosci 2020; 40:9103-9120. [PMID: 33051350 DOI: 10.1523/jneurosci.0131-20.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 09/13/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Abstract
Microglia are dynamic immunosurveillance cells in the CNS. Whether microglia are protective or pathologic is context dependent; the outcome varies as a function of time relative to the stimulus, activation state of neighboring cells in the microenvironment or within progression of a particular disease. Although brain microglia can be "primed" using bacterial lipopolysaccharide (LPS)/endotoxin, it is unknown whether LPS delivered systemically can also induce neuroprotective microglia in the spinal cord. Here, we show that serial systemic injections of LPS (1 mg/kg, i.p., daily) for 4 consecutive days (LPSx4) consistently elicit a reactive spinal cord microglia response marked by dramatic morphologic changes, increased production of IL-1, and enhanced proliferation without triggering leukocyte recruitment or overt neuropathology. Following LPSx4, reactive microglia frequently contact spinal cord endothelial cells. Targeted ablation or selective expression of IL-1 and IL-1 receptor (IL-1R) in either microglia or endothelia reveal that IL-1-dependent signaling between these cells mediates microglia activation. Using a mouse model of ischemic spinal cord injury in male and female mice, we show that preoperative LPSx4 provides complete protection from ischemia-induced neuron loss and hindlimb paralysis. Neuroprotection is partly reversed by either pharmacological elimination of microglia or selective removal of IL-1R in microglia or endothelia. These data indicate that spinal cord microglia are amenable to therapeutic reprogramming via systemic manipulation and that this potential can be harnessed to protect the spinal cord from injury.SIGNIFICANCE STATEMENT Data in this report indicate that a neuroprotective spinal cord microglia response can be triggered by daily systemic injections of LPS over a period of 4 d (LPSx4). The LPSx4 regimen induces morphologic transformation and enhances proliferation of spinal cord microglia without causing neuropathology. Using advanced transgenic mouse technology, we show that IL-1-dependent microglia-endothelia cross talk is necessary for eliciting this spinal cord microglia phenotype and also for conferring optimal protection to spinal motor neurons from ischemic spinal cord injury (ISCI). Collectively, these novel data show that it is possible to consistently elicit spinal cord microglia via systemic delivery of inflammogens to achieve a therapeutically effective neuroprotective response against ISCI.
Collapse
|
16
|
Yamamoto M, Kim M, Imai H, Itakura Y, Ohtsuki G. Microglia-Triggered Plasticity of Intrinsic Excitability Modulates Psychomotor Behaviors in Acute Cerebellar Inflammation. Cell Rep 2020; 28:2923-2938.e8. [PMID: 31509752 DOI: 10.1016/j.celrep.2019.07.078] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 04/20/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022] Open
Abstract
Cerebellar dysfunction relates to various psychiatric disorders, including autism spectrum and depressive disorders. However, the physiological aspect is less advanced. Here, we investigate the immune-triggered hyperexcitability in the cerebellum on a wider scope. Activated microglia via exposure to bacterial endotoxin lipopolysaccharide or heat-killed Gram-negative bacteria induce a potentiation of the intrinsic excitability in Purkinje neurons, which is suppressed by microglia-activity inhibitor and microglia depletion. An inflammatory cytokine, tumor necrosis factor alpha (TNF-α), released from microglia via toll-like receptor 4, triggers this plasticity. Our two-photon FRET ATP imaging shows an increase in ATP concentration following endotoxin exposure. Both TNF-α and ATP secretion facilitate synaptic transmission. Region-specific inflammation in the cerebellum in vivo shows depression- and autistic-like behaviors. Furthermore, both TNF-α inhibition and microglia depletion revert such behavioral abnormality. Resting-state functional MRI reveals overconnectivity between the inflamed cerebellum and the prefrontal neocortical regions. Thus, immune activity in the cerebellum induces neuronal hyperexcitability and disruption of psychomotor behaviors in animals.
Collapse
Affiliation(s)
- Masamichi Yamamoto
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto University Hospital, Shogoin-Kawaramachi-cho, Sakyo-ward, Kyoto 606-8507, Japan
| | - Minsoo Kim
- The Hakubi Center for Advanced Research, Kyoto University, Yoshida, Sakyo-ward, Kyoto 606-8501, Japan; Department of Molecular and Cellular Physiology, Kyoto University Graduate School of Medicine, Yoshida-Konoe-cho, Sakyo-ward, Kyoto 606-8501, Japan
| | - Hirohiko Imai
- Department of Systems Science, Kyoto University Graduate School of Informatics, Yoshida-Honmachi, Sakyo-ward, Kyoto 606-8501, Japan
| | - Yamato Itakura
- Department of Biophysics, Kyoto University Graduate School of Science, Kitashirakawa-Oiwake-cho, Sakyo-ward, Kyoto 606-8502, Japan
| | - Gen Ohtsuki
- The Hakubi Center for Advanced Research, Kyoto University, Yoshida, Sakyo-ward, Kyoto 606-8501, Japan; Department of Biophysics, Kyoto University Graduate School of Science, Kitashirakawa-Oiwake-cho, Sakyo-ward, Kyoto 606-8502, Japan.
| |
Collapse
|
17
|
Presynaptic L-Type Ca 2+ Channels Increase Glutamate Release Probability and Excitatory Strength in the Hippocampus during Chronic Neuroinflammation. J Neurosci 2020; 40:6825-6841. [PMID: 32747440 DOI: 10.1523/jneurosci.2981-19.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/18/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation is involved in the pathogenesis of several neurologic disorders, including epilepsy. Both changes in the input/output functions of synaptic circuits and cell Ca2+ dysregulation participate in neuroinflammation, but their impact on neuron function in epilepsy is still poorly understood. Lipopolysaccharide (LPS), a toxic byproduct of bacterial lysis, has been extensively used to stimulate inflammatory responses both in vivo and in vitro LPS stimulates Toll-like receptor 4, an important mediator of the brain innate immune response that contributes to neuroinflammation processes. Although we report that Toll-like receptor 4 is expressed in both excitatory and inhibitory mouse hippocampal neurons (both sexes), its chronic stimulation by LPS induces a selective increase in the excitatory synaptic strength, characterized by enhanced synchronous and asynchronous glutamate release mechanisms. This effect is accompanied by a change in short-term plasticity with decreased facilitation, decreased post-tetanic potentiation, and increased depression. Quantal analysis demonstrated that the effects of LPS on excitatory transmission are attributable to an increase in the probability of release associated with an overall increased expression of L-type voltage-gated Ca2+ channels that, at presynaptic terminals, abnormally contributes to evoked glutamate release. Overall, these changes contribute to the excitatory/inhibitory imbalance that scales up neuronal network activity under inflammatory conditions. These results provide new molecular clues for treating hyperexcitability of hippocampal circuits associated with neuroinflammation in epilepsy and other neurologic disorders.SIGNIFICANCE STATEMENT Neuroinflammation is thought to have a pathogenetic role in epilepsy, a disorder characterized by an imbalance between excitation/inhibition. Fine adjustment of network excitability and regulation of synaptic strength are both implicated in the homeostatic maintenance of physiological levels of neuronal activity. Here, we focused on the effects of chronic neuroinflammation induced by lipopolysaccharides on hippocampal glutamatergic and GABAergic synaptic transmission. Our results show that, on chronic stimulation with lipopolysaccharides, glutamatergic, but not GABAergic, neurons exhibit an enhanced synaptic strength and changes in short-term plasticity because of an increased glutamate release that results from an anomalous contribution of L-type Ca2+ channels to neurotransmitter release.
Collapse
|
18
|
Semple BD, Dill LK, O'Brien TJ. Immune Challenges and Seizures: How Do Early Life Insults Influence Epileptogenesis? Front Pharmacol 2020; 11:2. [PMID: 32116690 PMCID: PMC7010861 DOI: 10.3389/fphar.2020.00002] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/03/2020] [Indexed: 12/16/2022] Open
Abstract
The development of epilepsy, a process known as epileptogenesis, often occurs later in life following a prenatal or early postnatal insult such as cerebral ischemia, stroke, brain trauma, or infection. These insults share common pathophysiological pathways involving innate immune activation including neuroinflammation, which is proposed to play a critical role in epileptogenesis. This review provides a comprehensive overview of the latest preclinical evidence demonstrating that early life immune challenges influence neuronal hyperexcitability and predispose an individual to later life epilepsy. Here, we consider the range of brain insults that may promote the onset of chronic recurrent spontaneous seizures at adulthood, spanning intrauterine insults (e.g. maternal immune activation), perinatal injuries (e.g. hypoxic–ischemic injury, perinatal stroke), and insults sustained during early postnatal life—such as fever-induced febrile seizures, traumatic brain injuries, infections, and environmental stressors. Importantly, all of these insults represent, to some extent, an immune challenge, triggering innate immune activation and implicating both central and systemic inflammation as drivers of epileptogenesis. Increasing evidence suggests that pro-inflammatory cytokines such as interleukin-1 and subsequent signaling pathways are important mediators of seizure onset and recurrence, as well as neuronal network plasticity changes in this context. Our current understanding of how early life immune challenges prime microglia and astrocytes will be explored, as well as how developmental age is a critical determinant of seizure susceptibility. Finally, we will consider the paradoxical phenomenon of preconditioning, whereby these same insults may conversely provide neuroprotection. Together, an improved appreciation of the neuroinflammatory mechanisms underlying the long-term epilepsy risk following early life insults may provide insight into opportunities to develop novel immunological anti-epileptogenic therapeutic strategies.
Collapse
Affiliation(s)
- Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, Alfred Health, Melbourne, VIC, Australia
| | - Larissa K Dill
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Neurology, Alfred Health, Melbourne, VIC, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, Alfred Health, Melbourne, VIC, Australia
| |
Collapse
|
19
|
Giacco V, Panattoni G, Medelin M, Bonechi E, Aldinucci A, Ballerini C, Ballerini L. Cytokine inflammatory threat, but not LPS one, shortens GABAergic synaptic currents in the mouse spinal cord organotypic cultures. J Neuroinflammation 2019; 16:127. [PMID: 31238967 PMCID: PMC6593520 DOI: 10.1186/s12974-019-1519-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/11/2019] [Indexed: 01/02/2023] Open
Abstract
Background Synaptic dysfunction, named synaptopathy, due to inflammatory status of the central nervous system (CNS) is a recognized factor potentially underlying both motor and cognitive dysfunctions in neurodegenerative diseases. To gain knowledge on the mechanistic interplay between local inflammation and synapse changes, we compared two diverse inflammatory paradigms, a cytokine cocktail (CKs; IL-1β, TNF-α, and GM-CSF) and LPS, and their ability to tune GABAergic current duration in spinal cord cultured circuits. Methods We exploit spinal organotypic cultures, single-cell electrophysiology, immunocytochemistry, and confocal microscopy to explore synaptic currents and resident neuroglia reactivity upon CK or LPS incubation. Results Local inflammation in slice cultures induced by CK or LPS stimulations boosts network activity; however, only CKs specifically reduced GABAergic current duration. We pharmacologically investigated the contribution of GABAAR α-subunits and suggested that a switch of GABAAR α1-subunit might have induced faster GABAAR decay time, weakening the inhibitory transmission. Conclusions Lower GABAergic current duration could contribute to providing an aberrant excitatory transmission critical for pre-motor circuit tasks and represent a specific feature of a CK cocktail able to mimic an inflammatory reaction that spreads in the CNS. Our results describe a selective mechanism that could be triggered during specific inflammatory stress. Electronic supplementary material The online version of this article (10.1186/s12974-019-1519-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Vincenzo Giacco
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.,Present address: Wolfson Centre for Age Related Disease, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Giulia Panattoni
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Manuela Medelin
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Elena Bonechi
- Department NEUROFARBA, University of Florence, 50139, Florence, Italy
| | | | - Clara Ballerini
- Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy.
| | - Laura Ballerini
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.
| |
Collapse
|
20
|
Istas O, Greenhalgh A, Cooper R. The Effects of a Bacterial Endotoxin on Behavior and Sensory-CNS-Motor Circuits in Drosophila melanogaster. INSECTS 2019; 10:insects10040115. [PMID: 31013568 PMCID: PMC6523965 DOI: 10.3390/insects10040115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 02/06/2023]
Abstract
The effect of bacterial sepsis on animal behavior and physiology is complex due to direct and indirect actions. The most common form of bacterial sepsis in humans is from gram-negative bacterial strains. The endotoxin (lipopolysaccharide, LPS) and/or associated peptidoglycans from the bacteria are the key agents to induce an immune response, which then produces a cascade of immunological consequences. However, there are direct actions of LPS and associated peptidoglycans on cells which are commonly overlooked. This study showed behavioral and neural changes in larval Drosophila fed commercially obtained LPS from Serratia marcescens. Locomotor behavior was not altered, but feeding behavior increased and responses to sensory tactile stimuli were decreased. In driving a sensory-central nervous system (CNS)-motor neural circuit in in-situ preparations, direct application of commercially obtained LPS initially increased evoked activity and then decreased and even stopped evoked responses in a dose-dependent manner. With acute LPS and associated peptidoglycans exposure (10 min), the depressed neural responses recovered within a few minutes after removal of LPS. Commercially obtained LPS induces a transitory hyperpolarization of the body wall muscles within seconds of exposure and alters activity within the CNS circuit. Thus, LPS and/or associated peptidoglycans have direct effects on body wall muscle without a secondary immune response.
Collapse
Affiliation(s)
- Oscar Istas
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
| | - Abigail Greenhalgh
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
| | - Robin Cooper
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
| |
Collapse
|
21
|
Feng M, Crowley NA, Patel A, Guo Y, Bugni SE, Luscher B. Reversal of a Treatment-Resistant, Depression-Related Brain State with the Kv7 Channel Opener Retigabine. Neuroscience 2019; 406:109-125. [PMID: 30858110 DOI: 10.1016/j.neuroscience.2019.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 12/27/2022]
Abstract
Neuroinflammation is associated with increased vulnerability to diverse psychiatric conditions, including treatment-resistant major depressive disorder (MDD). Here we assessed whether high fat diet (HFD) induced neuroinflammation may be suitable to model a treatment-resistant depressive-like brain state in mice. Male and female mice were fed a HFD for 18 weeks, followed by quantitation of glucose tolerance, inflammatory markers of brain tissue (TNFα, IL-6, IL-1β, Iba-1), neural excitability in the prelimbic cortex (PLC), as well as assessment of emotional reactivity and hedonic behavior in a battery of behavioral tests. In addition, we assessed the behavioral responsiveness of mice to fluoxetine, desipramine, ketamine, and the Kv7 channel opener and anticonvulsant retigabine. HFD exposure led to glucose intolerance and neuroinflammation in male mice, with similar but non-significant trends in females. Neuroinflammation of males was associated with anxious-depressive-like behavior and defects in working memory, along with neural hyperexcitability and increased Ih currents of pyramidal cells in the PLC. The behavioral changes were largely resistant to chronic treatment with fluoxetine and desipramine, as well as ketamine. By contrast, retigabine (also known as ezogabine) normalized neural excitability and Ih currents recorded from slices of HFD-treated animals and significantly ameliorated most of the behavioral impairments, without effects in control diet exposed animals. Thus, treatment resistant depressive-like brain states that are associated with chronic neuroinflammation may involve hyperexcitability of pyramidal neurons and may be effectively treated by retigabine.
Collapse
Affiliation(s)
- Mengyang Feng
- Department of Biology, Pennsylvania State University, University Park, PA 16802; Center for Molecular Investigation of Neurological Disorders (CMIND), The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Nicole A Crowley
- Department of Biology, Pennsylvania State University, University Park, PA 16802; Center for Molecular Investigation of Neurological Disorders (CMIND), The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Akshilkumar Patel
- Department of Biology, Pennsylvania State University, University Park, PA 16802; Center for Molecular Investigation of Neurological Disorders (CMIND), The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Yao Guo
- Department of Biology, Pennsylvania State University, University Park, PA 16802; Center for Molecular Investigation of Neurological Disorders (CMIND), The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Sierra E Bugni
- Department of Biology, Pennsylvania State University, University Park, PA 16802; Center for Molecular Investigation of Neurological Disorders (CMIND), The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Bernhard Luscher
- Department of Biology, Pennsylvania State University, University Park, PA 16802; Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802; Center for Molecular Investigation of Neurological Disorders (CMIND), The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802.
| |
Collapse
|
22
|
Synaptic transmission and excitability during hypoxia with inflammation and reoxygenation in hippocampal CA1 neurons. Neuropharmacology 2018; 138:20-31. [PMID: 29775678 DOI: 10.1016/j.neuropharm.2018.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/19/2018] [Accepted: 05/08/2018] [Indexed: 12/30/2022]
Abstract
Although a number of experimental and clinical studies have shown that hypoxia typically accompanies acute inflammatory responses, the combinatorial effect of the two insults on basic neural function has not been thoroughly investigated. Previous studies have predominantly suggested that hypoxia reduces network activity; however, several studies suggest the opposite effect. Of note, inflammation is known to increase neural activity. In the current study, we examined the effects of limited oxygen in combination with an inflammatory stimulus, as well as the effects of reoxygenation, on synaptic transmission and excitability. We observed a significant reduction of both synaptic transmission and excitability when hypoxia and inflammation occurred in combination, whereas reoxygenation caused hyperexcitability of neurons. Further, we found that the observed reduction in synaptic transmission was due to compromised presynaptic release efficiency based on an adenosine-receptor-dependent increase in synaptic facilitation. Excitability changes in both directions were attributable to dynamic regulation of the hyperpolarization-activated cation current (Ih) and to changes in the input resistance and the voltage difference between resting membrane potential and action potential threshold. We found that zatebradine, an Ih current inhibitor, reduced the fluctuation in excitability, suggesting that it may have potential as a drug to ameliorate reperfusion brain injury.
Collapse
|
23
|
Zhu Y, Liu Z, Peng YP, Qiu YH. Interleukin-10 inhibits neuroinflammation-mediated apoptosis of ventral mesencephalic neurons via JAK-STAT3 pathway. Int Immunopharmacol 2017; 50:353-360. [PMID: 28753520 DOI: 10.1016/j.intimp.2017.07.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/28/2017] [Accepted: 07/19/2017] [Indexed: 01/15/2023]
Abstract
Neuroinflammation plays an important role in the pathogenesis of Parkinson's disease. Interleukin (IL)-10 is one of the most important and best anti-inflammatory cytokines. The objective of this report is to investigate whether IL-10 has any role in protecting ventral mesencephalic (VM) neurons in in vitro model of neuroinflammation. In this study, primary neuron-enriched culture was prepared from the VM tissues of E14 embryos of rats. The cells were pretreated with IL-10 (15 or 50ng/mL) for 1h followed by lipopolysaccharide (LPS, 50ng/mL) application. We found LPS induced neuronal apoptosis and loss while pretreatment with IL-10 reduced neuronal damage after exposure of LPS toxicity. Furthermore, signal transduction pathways related to IL-10 in VM neurons were studied in inflammatory condition. We used both shRNA and pharmacologic inhibition to determine the role of the IL-10 receptor (IL-10R) and its downstream signaling pathways in LPS-induced VM neuronal toxicity. Silence of the IL-10R gene in VM neurons abolished IL-10 mediated protection and the properties of anti-inflammatory and anti-apoptosis. IL-10 also induced phosphorylation of signal transducer and activator of transcription (STAT) 3 in VM neurons. Pretreatment with the specific Janus kinase (JAK) inhibitor reduced STAT3 phosphorylation and blocked IL-10 mediated protection against LPS. These findings suggest that IL-10 provides neuroprotection by acting via IL-10R and its down-stream JAK-STAT3 signal pathways in VM neurons.
Collapse
Affiliation(s)
- Yan Zhu
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu Province 226001, China
| | - Zhan Liu
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu Province 226001, China
| | - Yu-Ping Peng
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu Province 226001, China.
| | - Yi-Hua Qiu
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu Province 226001, China.
| |
Collapse
|
24
|
Peña-Ortega F. Pharmacological Tools to Activate Microglia and their Possible use to Study Neural Network Patho-physiology. Curr Neuropharmacol 2017; 15:595-619. [PMID: 27697040 PMCID: PMC5543677 DOI: 10.2174/1570159x14666160928151546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/05/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microglia are the resident immunocompetent cells of the CNS and also constitute a unique cell type that contributes to neural network homeostasis and function. Understanding microglia cell-signaling not only will reveal their diverse functions but also will help to identify pharmacological and non-pharmacological tools to modulate the activity of these cells. METHODS We undertook a search of bibliographic databases for peer-reviewed research literature to identify microglial activators and their cell-specificity. We also looked for their effects on neural network function and dysfunction. RESULTS We identified several pharmacological targets to modulate microglial function, which are more or less specific (with the proper control experiments). We also identified pharmacological targets that would require the development of new potent and specific modulators. We identified a wealth of evidence about the participation of microglia in neural network function and their alterations in pathological conditions. CONCLUSION The identification of specific microglia-activating signals provides experimental tools to modulate the activity of this heterogeneous cell type in order to evaluate its impact on other components of the nervous system, and it also helps to identify therapeutic approaches to ease some pathological conditions related to microglial dysfunction.
Collapse
Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| |
Collapse
|
25
|
Tzour A, Leibovich H, Barkai O, Biala Y, Lev S, Yaari Y, Binshtok AM. K V 7/M channels as targets for lipopolysaccharide-induced inflammatory neuronal hyperexcitability. J Physiol 2016; 595:713-738. [PMID: 27506492 DOI: 10.1113/jp272547] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/27/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Neuroinflammation associated with CNS insults leads to neuronal hyperexcitability, which may culminate in epileptiform discharges. Application of the endotoxin lipopolysaccharide (LPS) to brain tissue initiates a neuroinflammatory cascade, providing an experimental model to study the mechanisms of neuroinflammatory neuronal hyperexcitability. Here we show that LPS application to hippocampal slices markedly enhances the excitability of CA1 pyramidal cells by inhibiting a specific potassium current, the M-current, generated by KV 7/M channels, which controls the excitability of almost every neuron in the CNS. The LPS-induced M-current inhibition is triggered by sequential activation of microglia, astrocytes and pyramidal cells, mediated by metabotropic purinergic and glutamatergic transmission, leading to blockade of KV 7/M channels by calcium released from intracellular stores. The identification of the downstream molecular target of neuroinflammation, namely the KV 7/M channel, potentially has far reaching implications for the understanding and treatment of many acute and chronic brain disorders. ABSTRACT Acute brain insults and many chronic brain diseases manifest an innate inflammatory response. The hallmark of this response is glia activation, which promotes repair of damaged tissue, but also induces structural and functional changes that may lead to an increase in neuronal excitability. We have investigated the mechanisms involved in the modulation of neuronal activity by acute inflammation. Initiating inflammatory responses in hippocampal tissue rapidly led to neuronal depolarization and repetitive firing even in the absence of active synaptic transmission. This action was mediated by a complex metabotropic purinergic and glutamatergic glia-to-neuron signalling cascade, leading to the blockade of neuronal KV 7/M channels by Ca2+ released from internal stores. These channels generate the low voltage-activating, non-inactivating M-type K+ current (M-current) that controls intrinsic neuronal excitability, and its inhibition was the predominant cause of the inflammation-induced hyperexcitability. Our discovery that the ubiquitous KV 7/M channels are the downstream target of the inflammation-induced cascade, has far reaching implications for the understanding and treatment of many acute and chronic brain disorders.
Collapse
Affiliation(s)
- Arik Tzour
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel.,The Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
| | - Hodaya Leibovich
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel.,The Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
| | - Omer Barkai
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel.,The Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
| | - Yoav Biala
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
| | - Shaya Lev
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel.,The Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
| | - Yoel Yaari
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
| | - Alexander M Binshtok
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel.,The Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Israel
| |
Collapse
|
26
|
Montesinos J, Alfonso-Loeches S, Guerri C. Impact of the Innate Immune Response in the Actions of Ethanol on the Central Nervous System. Alcohol Clin Exp Res 2016; 40:2260-2270. [PMID: 27650785 DOI: 10.1111/acer.13208] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/02/2016] [Indexed: 12/25/2022]
Abstract
The innate immune response in the central nervous system (CNS) participates in both synaptic plasticity and neural damage. Emerging evidence from human and animal studies supports the role of the neuroimmune system response in many actions of ethanol (EtOH) on the CNS. Research studies have shown that alcohol stimulates brain immune cells, microglia, and astrocytes, by activating innate immune receptors Toll-like receptors (TLRs) and NOD-like receptors (inflammasome NLRs) triggering signaling pathways, which culminate in the production of pro-inflammatory cytokines and chemokines that lead to neuroinflammation. This review focuses on evidence that indicates the participation of TLRs and the inflammasome NLRs signaling response in many effects of EtOH on the CNS, such as neuroinflammation associated with brain damage, cognitive and behavioral dysfunction, and adolescent brain development alterations. It also reviews findings that indicate the role of TLR4-dependent signaling immune molecules in alcohol consumption, reward, and addiction. The research data suggest that overactivation of TLR4 or NLRs increases pro-inflammatory cytokines and mediators to cause neural damage in the cerebral cortex and hippocampus, while modest TLR4 activation, along with the generation of certain cytokines and chemokines in specific brain areas (e.g., amygdala, ventral tegmental area), modulate neurotransmission, alcohol drinking, and alcohol rewards. Elimination of TLR4 and NLRP3 abolishes many neuroimmune effects of EtOH. Despite much progress being made in this area, there are some research gaps and unanswered questions that this review discusses. Finally, potential therapies that target neuroimmune pathways to treat neuropathological and behavioral consequences of alcohol abuse are also evaluated.
Collapse
Affiliation(s)
- Jorge Montesinos
- Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia, Spain
| | - Silvia Alfonso-Loeches
- Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia, Spain
| | - Consuelo Guerri
- Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia, Spain.
| |
Collapse
|
27
|
Zhu Y, Chen X, Liu Z, Peng YP, Qiu YH. Interleukin-10 Protection against Lipopolysaccharide-Induced Neuro-Inflammation and Neurotoxicity in Ventral Mesencephalic Cultures. Int J Mol Sci 2015; 17:ijms17010025. [PMID: 26729090 PMCID: PMC4730272 DOI: 10.3390/ijms17010025] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 11/13/2015] [Accepted: 12/18/2015] [Indexed: 01/02/2023] Open
Abstract
Interleukin (IL)-10, an anti-inflammatory cytokine, is expressed in the brain and can inhibit microglial activation. Herein, we utilized lipopolysaccharide (LPS)-induced inflammatory Parkinson’s disease (PD) cell model to determine whether microglia and astrocytes are necessary targets for IL-10 neuroprotection. Primary ventral mesencephalic (VM) cultures with different composition of neurons, microglia and astrocytes were prepared. The cells were exposed to IL-10 (15, 50 or 150 ng/mL) 1 h prior to LPS (50 ng/mL) treatment. LPS induced dopaminergic and non-dopaminergic neuronal loss in VM cultures, VM neuron-enriched cultures, and neuron-microglia co-cultures, but not in neuron-astrocyte co-cultures. IL-10 reduced LPS-induced neuronal loss particularly in single VM neuron cultures. Pro-inflammatory mediators (TNF-α, IL-1β, inducible nitric oxide synthase and cyclooxygenase-2) were upregulated in both neuron-microglia and neuron-astrocyte co-cultures by LPS. In contrast, neurotrophic factors (brain-derived neurotrophic factor, insulin-like growth factor-1 or glial cell-derived neurotrophic factor) were downregulated in neuron-microglia co-cultures, but upregulated in neuron-astrocyte co-cultures by LPS. IL-10 reduced both the increase in production of the pro-inflammatory mediators and the decrease in production of the neurotrophic factors induced by LPS. These results suggest that astrocytes can balance LPS neurotoxicity by releasing more neurotrophic factors and that IL-10 exerts neuroprotective property by an extensive action including direct on neurons and indirect via inhibiting microglial activation.
Collapse
Affiliation(s)
- Yan Zhu
- School of Biological & Basic Medical Sciences, Soochow University, 199 Renai Road, Suzhou 215123, China.
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong 226001, China.
| | - Xiao Chen
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong 226001, China.
| | - Zhan Liu
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong 226001, China.
| | - Yu-Ping Peng
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong 226001, China.
| | - Yi-Hua Qiu
- Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong 226001, China.
| |
Collapse
|
28
|
Gullo F, Amadeo A, Donvito G, Lecchi M, Costa B, Constanti A, Wanke E. Atypical "seizure-like" activity in cortical reverberating networks in vitro can be caused by LPS-induced inflammation: a multi-electrode array study from a hundred neurons. Front Cell Neurosci 2014; 8:361. [PMID: 25404893 PMCID: PMC4217498 DOI: 10.3389/fncel.2014.00361] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/13/2014] [Indexed: 12/21/2022] Open
Abstract
We show here that a mild sterile inflammation induced by the endotoxin lipopolysaccharide (LPS), in a neuron/astrocyte/microglial cortical network, modulates neuronal excitability and can initiate long-duration burst events resembling epileptiform seizures, a recognized feature of various central nervous neurodegenerative, neurological and acute systemic diseases associated with neuroinflammation. To study this action, we simultaneously analyzed the reverberating bursting activity of a hundred neurons by using in vitro multi-electrode array methods. ∼5 h after LPS application, we observed a net increase in the average number of spikes elicited in engaged cells and within each burst, but no changes neither in spike waveforms nor in burst rate. This effect was characterized by a slow, twofold exponential increase of the burst duration and the appearance of rarely occurring long burst events that were never seen during control recordings. These changes and the time-course of microglia-released proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α), were blocked by pre-treatment with 50 nM minocycline, an established anti-inflammatory agent which was inactive when applied alone. Assay experiments also revealed that application of 60 pM exogenous TNF-α after 12–15 h, produced non-washable changes of neuronal excitability, completely different from those induced by LPS, suggesting that TNF-α release alone was not responsible for our observed findings. Our results indicate that the link between neuroinflammation and hyperexcitability can be unveiled by studying the long-term activity of in vitro neuronal/astrocyte/microglial networks.
Collapse
Affiliation(s)
- Francesca Gullo
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | - Alida Amadeo
- Department of Biomolecular Sciences and Biotechnology, University of Milan, Milan Italy
| | - Giulia Donvito
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | - Marzia Lecchi
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | - Barbara Costa
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | | | - Enzo Wanke
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| |
Collapse
|