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Targeting Microglia in Alzheimer’s Disease: From Molecular Mechanisms to Potential Therapeutic Targets for Small Molecules. Molecules 2022; 27:molecules27134124. [PMID: 35807370 PMCID: PMC9268715 DOI: 10.3390/molecules27134124] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 02/01/2023] Open
Abstract
Alzheimer’s disease (AD) is a common, progressive, and devastating neurodegenerative disorder that mainly affects the elderly. Microglial dysregulation, amyloid-beta (Aβ) plaques, and intracellular neurofibrillary tangles play crucial roles in the pathogenesis of AD. In the brain, microglia play roles as immune cells to provide protection against virus injuries and diseases. They have significant contributions in the development of the brain, cognition, homeostasis of the brain, and plasticity. Multiple studies have confirmed that uncontrolled microglial function can result in impaired microglial mitophagy, induced Aβ accumulation and tau pathology, and a chronic neuroinflammatory environment. In the brain, most of the genes that are associated with AD risk are highly expressed by microglia. Although it was initially regarded that microglia reaction is incidental and induced by dystrophic neurites and Aβ plaques. Nonetheless, it has been reported by genome-wide association studies that most of the risk loci for AD are located in genes that are occasionally uniquely and highly expressed in microglia. This finding further suggests that microglia play significant roles in early AD stages and they be targeted for the development of novel therapeutics. In this review, we have summarized the molecular pathogenesis of AD, microglial activities in the adult brain, the role of microglia in the aging brain, and the role of microglia in AD. We have also particularly focused on the significance of targeting microglia for the treatment of AD.
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152
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Sciatic nerve stimulation alleviates acute neuropathic pain via modulation of neuroinflammation and descending pain inhibition in a rodent model. J Neuroinflammation 2022; 19:153. [PMID: 35706025 PMCID: PMC9199305 DOI: 10.1186/s12974-022-02513-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 06/01/2022] [Indexed: 11/12/2022] Open
Abstract
Background Neuropathic pain (NP) is characterized by abnormal activation of pain conducting pathways and manifests as mechanical allodynia and thermal hypersensitivity. Peripheral nerve stimulation is used for treatment of medically refractory chronic NP and has been shown to reduce neuroinflammation. However, whether sciatic nerve stimulation (SNS) is of therapeutic benefit to NP remains unclear. Moreover, the optimal frequency for SNS is unknown. To address this research gap, we investigated the effect of SNS in an acute NP rodent model. Methods Rats with right L5 nerve root ligation (NRL) or Sham surgery were used. Ipsilateral SNS was performed at 2 Hz, 20 Hz, and 60 Hz frequencies. Behavioral tests were performed to assess pain and thermal hypersensitivity before and after NRL and SNS. Expression of inflammatory proteins in the L5 spinal cord and the immunohistochemical alterations of spinal cord astrocytes and microglia were examined on post-injury day 7 (PID7) following NRL and SNS. The involvement of the descending pain modulatory pathway was also investigated. Results Following NRL, the rats showed a decreased pain threshold and latency on the von Frey and Hargreaves tests. The immunofluorescence results indicated hyperactivation of superficial spinal cord dorsal horn (SCDH) neurons. Both 2-Hz and 20-Hz SNS alleviated pain behavior and hyperactivation of SCDH neurons. On PID7, NRL resulted in elevated expression of spinal cord inflammatory proteins including NF-κB, TNF-α, IL-1β, and IL-6, which was mitigated by 2-Hz and 20-Hz SNS. Furthermore, 2-Hz and 20-Hz SNS suppressed the activation of spinal cord astrocytes and microglia following NRL on PID7. Activity of the descending serotoninergic pain modulation pathway showed an increase early on PID1 following 2-Hz and 20-Hz SNS. Conclusions Our results support that both 2-Hz and 20-Hz SNS can alleviate NP behaviors and hyperactivation of pain conducting pathways. We showed that SNS regulates neuroinflammation and reduces inflammatory protein expression, astrocytic gliosis, and microglia activation. During the early post-injury period, SNS also facilitates the descending pain modulatory pathway. Taken together, these findings support the therapeutic potential of SNS for acute NP. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02513-y.
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153
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Du H, Wu D, Zhong S, Wei X, Yuan Z, Gong Q. MiR-106b-5p Attenuates Neuropathic Pain by Regulating the P2X4 Receptor in the Spinal Cord in Mice. J Mol Neurosci 2022; 72:1764-1778. [PMID: 35699833 DOI: 10.1007/s12031-022-02011-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/02/2022] [Indexed: 10/18/2022]
Abstract
The P2X4 receptor (P2X4R) can be upregulated after nerve injury, and its mediated spinal microglial activation makes a critical contribution to pathologically enhanced pain processing in the dorsal horn. Although some studies have partly clarified the mechanism underlying altered P2X4R expression, the specific mechanism is not well understood. MicroRNAs (miRNAs) are small noncoding RNAs which control gene expression by binding with their target mRNAs. Thus, in the present study, we investigated whether miRNA is involved in the pathogenesis of neuropathic pain by regulating P2X4R. Our results showed that P2X4R was upregulated in the spinal dorsal horn of mice following spared nerve injury (SNI), and 69 miRNAs (46 upregulated and 23 downregulated miRNAs) were differentially expressed (fold change > 2.0, P < 0.05). P2X4R was found to be a major target of miR-106b-5p (one of the downregulated miRNAs) using bioinformatics technology; quantitative real-time PCR analysis confirmed the change in expression of miR-106b-5p, and dual-luciferase reporter assays confirmed the correlation between them. Fluorescence in situ hybridization was used to show cell co-localization of P2X4R and miR-106b-5p in the spinal dorsal horn. Transfection with miR-106b-5p mimic into BV2 cells reversed the upregulation of P2X4R induced by lipopolysaccharide (LPS). Moreover, miR-106b-5p overexpression significantly attenuated neuropathic pain induced by SNI, with decreased expression of P2X4R mRNA and protein in the spinal dorsal horn; intrathecal miR-106b-5p antagomir induced pain behaviors, and increased expression of P2X4R in the spinal dorsal horn of naïve mice. These data suggest that miR-106b-5p can serve as an important regulator of neuropathic pain development by targeting P2X4R.
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Affiliation(s)
- Huiying Du
- Department of Pain Medicine, the Second Affiliated Hospital of Guangzhou Medical University, GuangzhouGuangdong, 510260, China.,Department of Anesthesiology, Guangdong Women and Children Hospital, GuangzhouGuangdong, 511442, China
| | - Danlei Wu
- Department of Pain Medicine, the Second Affiliated Hospital of Guangzhou Medical University, GuangzhouGuangdong, 510260, China
| | - Shuotao Zhong
- Department of Pain Medicine, the Second Affiliated Hospital of Guangzhou Medical University, GuangzhouGuangdong, 510260, China
| | - Xuhong Wei
- Department of Physiology and Pain Research Center, ZhongshanMedicalSchool, Sun Yat-Sen University, 74 Zhongshan Rd. 2, GuangzhouGuangdong, 510080, China
| | - Zhongmin Yuan
- Institute of Neuroscience and Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Qingjuan Gong
- Department of Pain Medicine, the Second Affiliated Hospital of Guangzhou Medical University, GuangzhouGuangdong, 510260, China.
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154
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Rawish E, Langer HF. Platelets and the Role of P2X Receptors in Nociception, Pain, Neuronal Toxicity and Thromboinflammation. Int J Mol Sci 2022; 23:6585. [PMID: 35743029 PMCID: PMC9224425 DOI: 10.3390/ijms23126585] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 12/24/2022] Open
Abstract
P2X receptors belong to a family of cation channel proteins, which respond to extracellular adenosine 5'-triphosphate (ATP). These receptors have gained increasing attention in basic and translational research, as they are central to a variety of important pathophysiological processes such as the modulation of cardiovascular physiology, mediation of nociception, platelet and macrophage activation, or neuronal-glial integration. While P2X1 receptor activation is long known to drive platelet aggregation, P2X7 receptor antagonists have recently been reported to inhibit platelet activation. Considering the role of both P2X receptors and platelet-mediated inflammation in neuronal diseases such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and stroke, targeting purinergic receptors may provide a valuable novel therapeutic approach in these diseases. Therefore, the present review illuminates the role of platelets and purinergic signaling in these neurological conditions to evaluate potential translational implications.
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Affiliation(s)
- Elias Rawish
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, 23538 Lübeck, Germany;
- University Hospital Schleswig-Holstein, Department of Cardiology, University Heart Center Lübeck, 23538 Lübeck, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, 23562 Lübeck, Germany
| | - Harald F. Langer
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, 23538 Lübeck, Germany;
- University Hospital Schleswig-Holstein, Department of Cardiology, University Heart Center Lübeck, 23538 Lübeck, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Lübeck/Kiel, 23562 Lübeck, Germany
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155
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Region-Specific Characteristics of Astrocytes and Microglia: A Possible Involvement in Aging and Diseases. Cells 2022; 11:cells11121902. [PMID: 35741031 PMCID: PMC9220858 DOI: 10.3390/cells11121902] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022] Open
Abstract
Although different regions of the brain are dedicated to specific functions, the intra- and inter-regional heterogeneity of astrocytes and microglia in these regions has not yet been fully understood. Recently, an advancement in various technologies, such as single-cell RNA sequencing, has allowed for the discovery of astrocytes and microglia with distinct molecular fingerprints and varying functions in the brain. In addition, the regional heterogeneity of astrocytes and microglia exhibits different functions in several situations, such as aging and neurodegenerative diseases. Therefore, investigating the region-specific astrocytes and microglia is important in understanding the overall function of the brain. In this review, we summarize up-to-date research on various intra- and inter-regional heterogeneities of astrocytes and microglia, and provide information on how they can be applied to aging and neurodegenerative diseases.
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156
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Gangadharan V, Zheng H, Taberner FJ, Landry J, Nees TA, Pistolic J, Agarwal N, Männich D, Benes V, Helmstaedter M, Ommer B, Lechner SG, Kuner T, Kuner R. Neuropathic pain caused by miswiring and abnormal end organ targeting. Nature 2022; 606:137-145. [PMID: 35614217 PMCID: PMC9159955 DOI: 10.1038/s41586-022-04777-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/20/2022] [Indexed: 12/12/2022]
Abstract
Nerve injury leads to chronic pain and exaggerated sensitivity to gentle touch (allodynia) as well as a loss of sensation in the areas in which injured and non-injured nerves come together1-3. The mechanisms that disambiguate these mixed and paradoxical symptoms are unknown. Here we longitudinally and non-invasively imaged genetically labelled populations of fibres that sense noxious stimuli (nociceptors) and gentle touch (low-threshold afferents) peripherally in the skin for longer than 10 months after nerve injury, while simultaneously tracking pain-related behaviour in the same mice. Fully denervated areas of skin initially lost sensation, gradually recovered normal sensitivity and developed marked allodynia and aversion to gentle touch several months after injury. This reinnervation-induced neuropathic pain involved nociceptors that sprouted into denervated territories precisely reproducing the initial pattern of innervation, were guided by blood vessels and showed irregular terminal connectivity in the skin and lowered activation thresholds mimicking low-threshold afferents. By contrast, low-threshold afferents-which normally mediate touch sensation as well as allodynia in intact nerve territories after injury4-7-did not reinnervate, leading to an aberrant innervation of tactile end organs such as Meissner corpuscles with nociceptors alone. Genetic ablation of nociceptors fully abrogated reinnervation allodynia. Our results thus reveal the emergence of a form of chronic neuropathic pain that is driven by structural plasticity, abnormal terminal connectivity and malfunction of nociceptors during reinnervation, and provide a mechanistic framework for the paradoxical sensory manifestations that are observed clinically and can impose a heavy burden on patients.
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Affiliation(s)
- Vijayan Gangadharan
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Hongwei Zheng
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Francisco J Taberner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Jonathan Landry
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Timo A Nees
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Jelena Pistolic
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Nitin Agarwal
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Deepitha Männich
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Björn Ommer
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
| | - Stefan G Lechner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Rohini Kuner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.
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Cerne R, Lippa A, Poe MM, Smith JL, Jin X, Ping X, Golani LK, Cook JM, Witkin JM. GABAkines - Advances in the discovery, development, and commercialization of positive allosteric modulators of GABA A receptors. Pharmacol Ther 2022; 234:108035. [PMID: 34793859 PMCID: PMC9787737 DOI: 10.1016/j.pharmthera.2021.108035] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 11/08/2021] [Indexed: 12/25/2022]
Abstract
Positive allosteric modulators of γ-aminobutyric acid-A (GABAA) receptors or GABAkines have been widely used medicines for over 70 years for anxiety, epilepsy, sleep, and other disorders. Traditional GABAkines like diazepam have safety and tolerability concerns that include sedation, motor-impairment, respiratory depression, tolerance and dependence. Multiple GABAkines have entered clinical development but the issue of side-effects has not been fully solved. The compounds that are presently being developed and commercialized include several neuroactive steroids (an allopregnanolone formulation (brexanolone), an allopregnanolone prodrug (LYT-300), Sage-324, zuranolone, and ganaxolone), the α2/3-preferring GABAkine, KRM-II-81, and the α2/3/5-preferring GABAkine PF-06372865 (darigabat). The neuroactive steroids are in clinical development for post-partum depression, intractable epilepsy, tremor, status epilepticus, and genetic epilepsy disorders. Darigabat is in development for epilepsy and anxiety. The imidazodiazepine, KRM-II-81 is efficacious in animal models for the treatment of epilepsy and post-traumatic epilepsy, acute and chronic pain, as well as anxiety and depression. The efficacy of KRM-II-81 in models of pharmacoresistant epilepsy, preventing the development of seizure sensitization, and in brain tissue of intractable epileptic patients bodes well for improved therapeutics. Medicinal chemistry efforts are also ongoing to identify novel and improved GABAkines. The data document gaps in our understanding of the molecular pharmacology of GABAkines that drive differential pharmacological profiles, but emphasize advancements in the ability to successfully utilize GABAA receptor potentiation for therapeutic gain in neurology and psychiatry.
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Affiliation(s)
- Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA,Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, Ljubljana, Slovenia.,RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Arnold Lippa
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA
| | | | - Jodi L. Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA
| | - Xiaoming Jin
- Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Xingjie Ping
- Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Lalit K. Golani
- Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - James M. Cook
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jeffrey M. Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA,RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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158
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Li J, Wei Y, Zhou J, Zou H, Ma L, Liu C, Xiao Z, Liu X, Tan X, Yu T, Cao S. Activation of locus coeruleus-spinal cord noradrenergic neurons alleviates neuropathic pain in mice via reducing neuroinflammation from astrocytes and microglia in spinal dorsal horn. J Neuroinflammation 2022; 19:123. [PMID: 35624514 PMCID: PMC9145151 DOI: 10.1186/s12974-022-02489-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 05/15/2022] [Indexed: 11/10/2022] Open
Abstract
Background The noradrenergic neurons of locus coeruleus (LC) project to the spinal dorsal horn (SDH), and release norepinephrine (NE) to inhibit pain transmission. However, its effect on pathological pain and the cellular mechanism in the SDH remains unclear. This study aimed to explore the analgesic effects and the anti-neuroinflammation mechanism of LC-spinal cord noradrenergic pathway (LC:SC) in neuropathic pain (NP) mice with sciatic chronic constriction injury. Methods The Designer Receptors Exclusively Activated by Designer Drugs (DREADD) was used to selectively activate LC:SC. Noradrenergic neuron-specific retro–adeno-associated virus was injected to the spinal cord. Pain threshold, LC and wide dynamic range (WDR) neuron firing, neuroinflammation (microglia and astrocyte activation, cytokine expression), and α2AR expression in SDH were evaluated. Results Activation of LC:SC with DREADD increased the mechanical and thermal nociceptive thresholds and reduced the WDR neuron firing. LC:SC activation (daily, 7 days) downregulated TNF-α and IL-1β expression, upregulated IL-4 and IL-10 expression in SDH, and inhibited microglia and astrocytes activation in NP mice. Immunofluorescence double staining confirmed that LC:SC activation decreased the expression of cytokines in microglia of the SDH. In addition, the effects of LC:SC activation could be reversed by intrathecal injection of yohimbine. Immunofluorescence of SDH showed that NE receptor α2B-AR was highly expressed in microglia in CCI mice. Conclusion These findings indicate that selective activation of LC:SC alleviates NP in mice by increasing the release of NE and reducing neuroinflammation of astrocytes and microglia in SDH. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02489-9.
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Affiliation(s)
- Juan Li
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China.,Department of Pain Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China
| | - Yiyong Wei
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China.,Guizhou Key Lab of Anesthesia and Organ Protection, Zunyi Medical University, 6 West Xuefu Street, Zunyi, 563099, Guizhou, China
| | - Junli Zhou
- Department of Pain Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China
| | - Helin Zou
- Department of Pain Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China
| | - Lulin Ma
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China
| | - Chengxi Liu
- Guizhou Key Lab of Anesthesia and Organ Protection, Zunyi Medical University, 6 West Xuefu Street, Zunyi, 563099, Guizhou, China
| | - Zhi Xiao
- Guizhou Key Lab of Anesthesia and Organ Protection, Zunyi Medical University, 6 West Xuefu Street, Zunyi, 563099, Guizhou, China
| | - Xingfeng Liu
- Guizhou Key Lab of Anesthesia and Organ Protection, Zunyi Medical University, 6 West Xuefu Street, Zunyi, 563099, Guizhou, China
| | - Xinran Tan
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China.,Department of Pain Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China
| | - Tian Yu
- Guizhou Key Lab of Anesthesia and Organ Protection, Zunyi Medical University, 6 West Xuefu Street, Zunyi, 563099, Guizhou, China
| | - Song Cao
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China. .,Department of Pain Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Street, Zunyi, 563000, Guizhou, China. .,Guizhou Key Lab of Anesthesia and Organ Protection, Zunyi Medical University, 6 West Xuefu Street, Zunyi, 563099, Guizhou, China.
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159
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Sophocleous RA, Ooi L, Sluyter R. The P2X4 Receptor: Cellular and Molecular Characteristics of a Promising Neuroinflammatory Target. Int J Mol Sci 2022; 23:ijms23105739. [PMID: 35628550 PMCID: PMC9147237 DOI: 10.3390/ijms23105739] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 02/07/2023] Open
Abstract
The adenosine 5′-triphosphate-gated P2X4 receptor channel is a promising target in neuroinflammatory disorders, but the ability to effectively target these receptors in models of neuroinflammation has presented a constant challenge. As such, the exact role of P2X4 receptors and their cell signalling mechanisms in human physiology and pathophysiology still requires further elucidation. To this end, research into the molecular mechanisms of P2X4 receptor activation, modulation, and inhibition has continued to gain momentum in an attempt to further describe the role of P2X4 receptors in neuroinflammation and other disease settings. Here we provide an overview of the current understanding of the P2X4 receptor, including its expression and function in cells involved in neuroinflammatory signalling. We discuss the pharmacology of P2X4 receptors and provide an overview of P2X4-targeting molecules, including agonists, positive allosteric modulators, and antagonists. Finally, we discuss the use of P2X4 receptor modulators and antagonists in models of neuroinflammatory cell signalling and disease.
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Affiliation(s)
- Reece Andrew Sophocleous
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (R.A.S.); (L.O.)
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (R.A.S.); (L.O.)
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Ronald Sluyter
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; (R.A.S.); (L.O.)
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Correspondence: ; Tel.: +612-4221-5508
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160
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Yang QH, Zhang YH, Du SH, Wang YC, Fang Y, Wang XQ. Non-invasive Brain Stimulation for Central Neuropathic Pain. Front Mol Neurosci 2022; 15:879909. [PMID: 35663263 PMCID: PMC9162797 DOI: 10.3389/fnmol.2022.879909] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 05/04/2022] [Indexed: 12/15/2022] Open
Abstract
The research and clinical application of the noninvasive brain stimulation (NIBS) technique in the treatment of neuropathic pain (NP) are increasing. In this review article, we outline the effectiveness and limitations of the NIBS approach in treating common central neuropathic pain (CNP). This article summarizes the research progress of NIBS in the treatment of different CNPs and describes the effects and mechanisms of these methods on different CNPs. Repetitive transcranial magnetic stimulation (rTMS) analgesic research has been relatively mature and applied to a variety of CNP treatments. But the optimal stimulation targets, stimulation intensity, and stimulation time of transcranial direct current stimulation (tDCS) for each type of CNP are still difficult to identify. The analgesic mechanism of rTMS is similar to that of tDCS, both of which change cortical excitability and synaptic plasticity, regulate the release of related neurotransmitters and affect the structural and functional connections of brain regions associated with pain processing and regulation. Some deficiencies are found in current NIBS relevant studies, such as small sample size, difficulty to avoid placebo effect, and insufficient research on analgesia mechanism. Future research should gradually carry out large-scale, multicenter studies to test the stability and reliability of the analgesic effects of NIBS.
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Affiliation(s)
- Qi-Hao Yang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yong-Hui Zhang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Shu-Hao Du
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yu-Chen Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yu Fang
- School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai, China
- *Correspondence: Yu Fang,
| | - Xue-Qiang Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
- Department of Rehabilitation Medicine, Shanghai Shangti Orthopaedic Hospital, Shanghai, China
- Xue-Qiang Wang,
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161
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Gonçalves de Andrade E, González Ibáñez F, Tremblay MÈ. Microglia as a Hub for Suicide Neuropathology: Future Investigation and Prevention Targets. Front Cell Neurosci 2022; 16:839396. [PMID: 35663424 PMCID: PMC9158339 DOI: 10.3389/fncel.2022.839396] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
Suicide is a complex public health challenge associated worldwide with one death every 40 s. Research advances in the neuropathology of suicidal behaviors (SB) have defined discrete brain changes which may hold the key to suicide prevention. Physiological differences in microglia, the resident immune cells of the brain, are present in post-mortem tissue samples of individuals who died by suicide. Furthermore, microglia are mechanistically implicated in the outcomes of important risk factors for SB, including early-life adversity, stressful life events, and psychiatric disorders. SB risk factors result in inflammatory and oxidative stress activities which could converge to microglial synaptic remodeling affecting susceptibility or resistance to SB. To push further this perspective, in this Review we summarize current areas of opportunity that could untangle the functional participation of microglia in the context of suicide. Our discussion centers around microglial state diversity in respect to morphology, gene and protein expression, as well as function, depending on various factors, namely brain region, age, and sex.
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Affiliation(s)
- Elisa Gonçalves de Andrade
- Neuroscience Graduate Program, Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Fernando González Ibáñez
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- *Correspondence: Marie-Ève Tremblay,
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162
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Liedtke W. Long March Toward Safe and Effective Analgesia by Enhancing Gene Expression of Kcc2: First Steps Taken. Front Mol Neurosci 2022; 15:865600. [PMID: 35645734 PMCID: PMC9137411 DOI: 10.3389/fnmol.2022.865600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/08/2022] [Indexed: 11/15/2022] Open
Abstract
Low intraneuronal chloride in spinal cord dorsal horn pain relay neurons is critical for physiologic transmission of primary pain afferents because low intraneuronal chloride dictates whether GABA-ergic and glycin-ergic neurotransmission is inhibitory. If the neuronal chloride elevates to pathologic levels, then spinal cord primary pain relay becomes leaky and exhibits the behavioral hallmarks of pathologic pain, namely hypersensitivity and allodynia. Low chloride in spinal cord dorsal horn neurons is maintained by proper gene expression of Kcc2 and sustained physiologic function of the KCC2 chloride extruding electroneutral transporter. Peripheral nerve injury and other forms of neural injury evoke greatly diminished Kcc2 gene expression and subsequent corruption of inhibitory neurotransmission in the spinal cord dorsal horn, thus causing derailment of the gate function for pain. Here I review key discoveries that have helped us understand these fundamentals, and focus on recent insights relating to the discovery of Kcc2 gene expression enhancing compounds via compound screens in neurons. One such study characterized the kinase inhibitor, kenpaullone, more in-depth, revealing its function as a robust and long-lasting analgesic in preclinical models of nerve injury and cancer bone pain, also elucidating its mechanism of action via GSK3β inhibition, diminishing delta-catenin phosphorylation, and facilitating its nuclear transfer and subsequent enhancement of Kcc2 gene expression by de-repressing Kaiso epigenetic transcriptional regulator. Future directions re Kcc2 gene expression enhancement are discussed, namely combination with other analgesics and analgesic methods, such as spinal cord stimulation and electroacupuncture, gene therapy, and leveraging Kcc2 gene expression-enhancing nanomaterials.
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163
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Wang R, Zhou R, Chen Z, Gao S, Zhou F. The Glial Cells Respond to Spinal Cord Injury. Front Neurol 2022; 13:844497. [PMID: 35599739 PMCID: PMC9120539 DOI: 10.3389/fneur.2022.844497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 03/08/2022] [Indexed: 12/24/2022] Open
Abstract
It is been over 100 years since glial cells were discovered by Virchow. Since then, a great deal of research was carried out to specify these further roles and properties of glial cells in central nervous system (CNS). As it is well-known that glial cells, such as astrocytes, microglia, oligodendrocytes (OLs), and oligodendrocyte progenitor cells (OPCs) play an important role in supporting and enabling the effective nervous system function in CNS. After spinal cord injury (SCI), these glial cells play different roles in SCI and repair. In this review, we will discuss in detail about the role of glial cells in the healthy CNS and how they respond to SCI.
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164
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Hiraga SI, Itokazu T, Nishibe M, Yamashita T. Neuroplasticity related to chronic pain and its modulation by microglia. Inflamm Regen 2022; 42:15. [PMID: 35501933 PMCID: PMC9063368 DOI: 10.1186/s41232-022-00199-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/19/2022] [Indexed: 01/03/2023] Open
Abstract
Neuropathic pain is often chronic and can persist after overt tissue damage heals, suggesting that its underlying mechanism involves the alteration of neuronal function. Such an alteration can be a direct consequence of nerve damage or a result of neuroplasticity secondary to the damage to tissues or to neurons. Recent studies have shown that neuroplasticity is linked to causing neuropathic pain in response to nerve damage, which may occur adjacent to or remotely from the site of injury. Furthermore, studies have revealed that neuroplasticity relevant to chronic pain is modulated by microglia, resident immune cells of the central nervous system (CNS). Microglia may directly contribute to synaptic remodeling and altering pain circuits, or indirectly contribute to neuroplasticity through property changes, including the secretion of growth factors. We herein highlight the mechanisms underlying neuroplasticity that occur in the somatosensory circuit of the spinal dorsal horn, thalamus, and cortex associated with chronic pain following injury to the peripheral nervous system (PNS) or CNS. We also discuss the dynamic functions of microglia in shaping neuroplasticity related to chronic pain. We suggest further understanding of post-injury ectopic plasticity in the somatosensory circuits may shed light on the differential mechanisms underlying nociceptive, neuropathic, and nociplastic-type pain. While one of the prominent roles played by microglia appears to be the modulation of post-injury neuroplasticity. Therefore, future molecular- or genetics-based studies that address microglia-mediated post-injury neuroplasticity may contribute to the development of novel therapies for chronic pain.
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Affiliation(s)
- Shin-Ichiro Hiraga
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Takahide Itokazu
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. .,Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
| | - Mariko Nishibe
- Center for Strategic Innovative Dentistry, Graduate School of Dentistry, Osaka University, Suita, Osaka, Japan
| | - Toshihide Yamashita
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. .,Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. .,WPI Immunology Frontier Research Center, Osaka, Japan. .,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
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165
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Gibel-Russo R, Benacom D, Di Nardo AA. Non-Cell-Autonomous Factors Implicated in Parvalbumin Interneuron Maturation and Critical Periods. Front Neural Circuits 2022; 16:875873. [PMID: 35601531 PMCID: PMC9115720 DOI: 10.3389/fncir.2022.875873] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/04/2022] [Indexed: 02/04/2023] Open
Abstract
From birth to adolescence, the brain adapts to its environmental stimuli through structural and functional remodeling of neural circuits during critical periods of heightened plasticity. They occur across modalities for proper sensory, motor, linguistic, and cognitive development. If they are disrupted by early-life adverse experiences or genetic deficiencies, lasting consequences include behavioral changes, physiological and cognitive deficits, or psychiatric illness. Critical period timing is orchestrated not only by appropriate neural activity but also by a multitude of signals that participate in the maturation of fast-spiking parvalbumin interneurons and the consolidation of neural circuits. In this review, we describe the various signaling factors that initiate critical period onset, such as BDNF, SPARCL1, or OTX2, which originate either from local neurons or glial cells or from extracortical sources such as the choroid plexus. Critical period closure is established by signals that modulate extracellular matrix and myelination, while timing and plasticity can also be influenced by circadian rhythms and by hormones and corticosteroids that affect brain oxidative stress levels or immune response. Molecular outcomes include lasting epigenetic changes which themselves can be considered signals that shape downstream cross-modal critical periods. Comprehensive knowledge of how these signals and signaling factors interplay to influence neural mechanisms will help provide an inclusive perspective on the effects of early adversity and developmental defects that permanently change perception and behavior.
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166
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Spinal Cord Stimulation to Treat Unresponsive Cancer Pain: A Possible Solution in Palliative Oncological Therapy. Life (Basel) 2022; 12:life12040554. [PMID: 35455045 PMCID: PMC9025741 DOI: 10.3390/life12040554] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 12/03/2022] Open
Abstract
(1) Background: Treatment of cancer-related pain is still challenging, and it can be managed by both medical and interventional therapies. Spinal Cord Stimulation (SCS) is a minimally invasive technique, and its use is rapidly increasing in the treatment of chronic pain. (2) Materials and Methods: Our study aims to perform a review of the pertinent literature about current evidences in cancer pain treatment by Spinal Cord Stimulation. Moreover, we created a database based on case reports or case series (18 studies) in the literature. We analyzed a clinical group of oncological patients affected by intractable pain undergoing SCS implantation, focusing on outcome. (3) Results: The analysis of the 18 included studies in our series has shown a reduction in painful symptoms in 48 out of 56 treated patients (87.51%); also 53 out of 56 patients (96.64%) have shown an improvement in their Quality of Life (QoL). (4) Conclusions: Spinal Cord Stimulation can be considered an efficient method in the treatment of cancer-related pain. However, literature regarding SCS for the treatment of cancer-related pain is largely represented by case reports and small case series, with no effective population studies or Randomized Controlled Trials demonstrating the efficacy and the level of evidence. Further prospective studies are needed.
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167
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Hiroki T, Suto T, Ohta J, Saito S, Obata H. Spinal γ-Aminobutyric Acid Interneuron Plasticity Is Involved in the Reduced Analgesic Effects of Morphine on Neuropathic Pain. THE JOURNAL OF PAIN 2022; 23:547-557. [PMID: 34678470 DOI: 10.1016/j.jpain.2021.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/16/2021] [Accepted: 10/05/2021] [Indexed: 12/25/2022]
Abstract
Systemic administration of morphine increases serotonin (5-HT) in the spinal dorsal horn (SDH), which attenuates the analgesic effects of morphine on neuropathic pain through spinal 5-HT3 receptors. We hypothesized that dysfunction of the descending serotonergic system, including the periaqueductal gray (PAG), contributes to attenuate the efficacy of morphine on neuropathic pain through spinal 5-HT3 receptors and GABA neurons. Morphine (100 ng) injected into the PAG produced analgesic effects in normal rats, but not in spinal nerve ligation (SNL) rats. In vivo microdialysis showed that PAG morphine increased the SDH 5-HT concentration in both groups. Intrathecal injection of the 5-HT3 receptor antagonist ondansetron and the GABAA receptor antagonist bicuculline attenuated the analgesic effects of PAG morphine in normal rats, but increased the effects in SNL rats. The increased analgesic effect of PAG morphine induced by bicuculline was reversed by pretreatment with the tropomyosin receptor kinase B (TrkB) antagonist K252a. Activation of spinal 5-HT3 receptors by 2-methyl-5-HT increased the GABA concentration in both groups. Morphine activates GABAergic interneurons in the SDH by activating descending serotonergic neurons. Functional changes in GABAA receptors from inhibitory to facilitatory through the activation of TrkB receptors may contribute to the attenuated efficacy of morphine against neuropathic pain. PERSPECTIVE: Although morphine provides strong analgesia against acute pain, it has limited efficacy against neuropathic pain. This article demonstrates that functional changes in GABAA receptors in the spinal dorsal horn after nerve injury might strongly contribute to the attenuation of opioid-induced analgesia for neuropathic pain.
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Affiliation(s)
- Tadanao Hiroki
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan.
| | - Takashi Suto
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Jo Ohta
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Shigeru Saito
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Hideaki Obata
- Department of Anesthesiology, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
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168
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Folick A, Cheang RT, Valdearcos M, Koliwad SK. Metabolic factors in the regulation of hypothalamic innate immune responses in obesity. Exp Mol Med 2022; 54:393-402. [PMID: 35474339 PMCID: PMC9076660 DOI: 10.1038/s12276-021-00666-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 05/13/2021] [Indexed: 12/14/2022] Open
Abstract
The hypothalamus is a central regulator of body weight and energy homeostasis. There is increasing evidence that innate immune activation in the mediobasal hypothalamus (MBH) is a key element in the pathogenesis of diet-induced obesity. Microglia, the resident immune cells in the brain parenchyma, have been shown to play roles in diverse aspects of brain function, including circuit refinement and synaptic pruning. As such, microglia have also been implicated in the development and progression of neurological diseases. Microglia express receptors for and are responsive to a wide variety of nutritional, hormonal, and immunological signals that modulate their distinct functions across different brain regions. We showed that microglia within the MBH sense and respond to a high-fat diet and regulate the function of hypothalamic neurons to promote food intake and obesity. Neurons, glia, and immune cells within the MBH are positioned to sense and respond to circulating signals that regulate their capacity to coordinate aspects of systemic energy metabolism. Here, we review the current knowledge of how these peripheral signals modulate the innate immune response in the MBH and enable microglia to regulate metabolic control.
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Affiliation(s)
- Andrew Folick
- Diabetes Center and Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA, USA
| | - Rachel T Cheang
- Diabetes Center and Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA, USA
| | - Martin Valdearcos
- Diabetes Center and Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA, USA.
| | - Suneil K Koliwad
- Diabetes Center and Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA, USA.
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169
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Inoue K. Overview for the study of P2 receptors: From P2 receptor history to neuropathic pain studies. J Pharmacol Sci 2022; 149:73-80. [DOI: 10.1016/j.jphs.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/25/2022] Open
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170
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Mortensen D, Thoefner MS, Agerholm JS, Slumstrup L, Jensen TS, Bjerrum OJ, Berendt M, Nyengaard JR. Dorsal horn volume loss and pain pathway changes in Cavalier King Charles Spaniels with syringomyelia, signs of pain, and phantom scratching. Pain 2022; 163:2365-2379. [PMID: 35353770 DOI: 10.1097/j.pain.0000000000002630] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 02/28/2022] [Indexed: 11/25/2022]
Abstract
ABSTRACT Central neuropathic pain is a core clinical sign of syringomyelia in humans and Cavalier King Charles Spaniel (CKCS) dogs. This histopathological study used spinal cords from CKCS with syringomyelia to investigate: 1) whether specific structural cervical spinal cord entities involved in nociception are affected by loss of neuroparenchyma or other pathological changes in CKCS with pain-related behaviour and phantom scratching, 2) if pain related behaviour or phantom scratching correlated with loss of a specific anatomical entity or upregulation of glia cells, and 3) if syringomyelia-related lesions affected specific functional spinal cord units of nociception.Spinal cord segments C1-C8 from CKCS with MRI-confirmed syringomyelia and clinical signs of pain and phantom scratch (n=8) were compared to CKCS without syringomyelia (n=4). Dogs with unilateral scratching (n=7) had a volume loss (P=0.043) of the dorsal horn laminae I-III in the ipsilateral side compared to the contralateral dorsal horn. A clear pattern of ipsilateral changes in the dorsal root entry zone characterised by deafferentation and reorganization of first-order axons into deeper laminae was found in cases with lateralised scratching. Significant changes in cell number density were not found for astrocytes or microglia, suggesting that the dogs represented cases of end-stage syringomyelia and thus could not reveal astrogliosis and microgliosis, which may be involved in the early phases of syrinx development and phantom scratch.The present relationship between clinical findings and dorsal horn and pain pathway pathology in CKCS suggests that these dogs may be of interest as a supplement to experimental model pain research.
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Affiliation(s)
- Danny Mortensen
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Center for Stochastic Geometry and Advanced Bioimaging
| | - Maria Soendergaard Thoefner
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Joergen Steen Agerholm
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Lasse Slumstrup
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Center for Stochastic Geometry and Advanced Bioimaging
| | | | - Ole Jannik Bjerrum
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen
| | - Mette Berendt
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jens Randel Nyengaard
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Center for Stochastic Geometry and Advanced Bioimaging.,Department of Pathology, Aarhus University Hospital, Denmark
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171
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Yan W, Liu W, Wu J, Wu L, Xuan S, Wang W, Shang A. Neuropeptide Y in the amygdala contributes to neuropathic pain-like behaviors in rats via the neuropeptide Y receptor type 2/mitogen-activated protein kinase axis. Bioengineered 2022; 13:8101-8114. [PMID: 35313782 PMCID: PMC9162000 DOI: 10.1080/21655979.2022.2051783] [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] [Indexed: 11/04/2022] Open
Abstract
Neuropeptide Y (NPY) is a highly conserved endogenous peptide in the central and peripheral nervous systems, which has been implicated in nociceptive signaling in neuropathic pain. However, downstream mechanistic actions remain uncharacterized. In this study, we sought to investigate the mechanism of NPY and its receptor NPY2R in the amygdala in rats with neuropathic pain-like behaviors induced by chronic constriction injury (CCI) of the sciatic nerve. The expression of NPY and NPY2R was found to be aberrantly up-regulated in neuropathic pain-related microarray dataset. Further, NPY was found to act on NPY2R in the basolateral amygdala (BLA). As reflected by the decrease in mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) as well as the increase of NPY expression in the amygdala of rats with neuropathic pain-like behaviors, NPY was closely related to the effect of amygdala nerve activity in neuropathic pain. Subsequently, mechanistic investigations indicated that NPY2R activated the MAPK signaling pathway in the amygdala. NPY2R-induced decrease of MWT and TWL were also restored in the presence of MAPK signaling pathway antagonist. Moreover, it was revealed that NPY2R overexpression promoted the viability while inhibiting the apoptosis of microglia. Taken together, NPY in the amygdala interacts with NPY2R to activate the MAPK signaling pathway, thereby promoting the occurrence of neuropathic pain.
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Affiliation(s)
- Wenhui Yan
- Department of Laboratory Medicine Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Tongji University School of Medicine, Shanghai, P.R. China.,Department of Laboratory Medicine, Tinghu People's Hospital, Yancheng, P.R. China
| | - Wuchao Liu
- Department of Neurorehabilitation, Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Tongji University School of Medicine, Shanghai, P.R. China
| | - Junlu Wu
- Department of Laboratory Medicine, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai, P.R. China
| | - Lipei Wu
- Department of Laboratory Medicine, Dongtai People's Hospital & Dongtai Hospital of Nantong University, Yancheng, P.R. China
| | - Shihai Xuan
- Department of Laboratory Medicine, Dongtai People's Hospital & Dongtai Hospital of Nantong University, Yancheng, P.R. China
| | - Weiwei Wang
- Department of Pathology, Tinghu People's Hospital, Yancheng, P.R. China
| | - Anquan Shang
- Department of Laboratory Medicine, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai, P.R. China
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172
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Dedek A, Xu J, Lorenzo LÉ, Godin AG, Kandegedara CM, Glavina G, Landrigan JA, Lombroso PJ, De Koninck Y, Tsai EC, Hildebrand ME. Sexual dimorphism in a neuronal mechanism of spinal hyperexcitability across rodent and human models of pathological pain. Brain 2022; 145:1124-1138. [PMID: 35323848 PMCID: PMC9050559 DOI: 10.1093/brain/awab408] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/03/2021] [Accepted: 10/15/2021] [Indexed: 12/23/2022] Open
Abstract
The prevalence and severity of many chronic pain syndromes differ across sex, and recent studies have identified differences in immune signalling within spinal nociceptive circuits as a potential mediator. Although it has been proposed that sex-specific pain mechanisms converge once they reach neurons within the superficial dorsal horn, direct investigations using rodent and human preclinical pain models have been lacking. Here, we discovered that in the Freund’s adjuvant in vivo model of inflammatory pain, where both male and female rats display tactile allodynia, a pathological coupling between KCC2-dependent disinhibition and N-methyl-D-aspartate receptor (NMDAR) potentiation within superficial dorsal horn neurons was observed in male but not female rats. Unlike males, the neuroimmune mediator brain-derived neurotrophic factor (BDNF) failed to downregulate inhibitory signalling elements (KCC2 and STEP61) and upregulate excitatory elements (pFyn, GluN2B and pGluN2B) in female rats, resulting in no effect of ex vivo brain-derived neurotrophic factor on synaptic NMDAR responses in female lamina I neurons. Importantly, this sex difference in spinal pain processing was conserved from rodents to humans. As in rodents, ex vivo spinal treatment with BDNF downregulated markers of disinhibition and upregulated markers of facilitated excitation in superficial dorsal horn neurons from male but not female human organ donors. Ovariectomy in female rats recapitulated the male pathological pain neuronal phenotype, with BDNF driving a coupling between disinhibition and NMDAR potentiation in adult lamina I neurons following the prepubescent elimination of sex hormones in females. This discovery of sexual dimorphism in a central neuronal mechanism of chronic pain across species provides a foundational step towards a better understanding and treatment for pain in both sexes.
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Affiliation(s)
- Annemarie Dedek
- Department of Neuroscience, Carleton University, K1S 5B6 Ontario, Canada.,Neuroscience Program, Ottawa Hospital Research Institute, K1Y 4M9 Ontario, Canada
| | - Jian Xu
- Child Study Center, Yale University School of Medicine, New Haven, CT 06519, USA
| | | | - Antoine G Godin
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec G1E 1T2, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Quebec G1V 0A6, Canada
| | - Chaya M Kandegedara
- Department of Neuroscience, Carleton University, K1S 5B6 Ontario, Canada.,Neuroscience Program, Ottawa Hospital Research Institute, K1Y 4M9 Ontario, Canada
| | - Geneviève Glavina
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec G1E 1T2, Canada
| | | | - Paul J Lombroso
- Child Study Center, Yale University School of Medicine, New Haven, CT 06519, USA
| | - Yves De Koninck
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec G1E 1T2, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Quebec G1V 0A6, Canada
| | - Eve C Tsai
- Neuroscience Program, Ottawa Hospital Research Institute, K1Y 4M9 Ontario, Canada.,Brain and Mind Research Institute, University of Ottawa, Ontario K1N 6N5, Canada.,Department of Surgery, Division of Neurosurgery, The Ottawa Hospital, Ontario K1Y 4E9, Canada
| | - Michael E Hildebrand
- Department of Neuroscience, Carleton University, K1S 5B6 Ontario, Canada.,Neuroscience Program, Ottawa Hospital Research Institute, K1Y 4M9 Ontario, Canada
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173
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Tozaki-Saitoh H, Takeda H, Inoue K. The Role of Microglial Purinergic Receptors in Pain Signaling. Molecules 2022; 27:molecules27061919. [PMID: 35335282 PMCID: PMC8949888 DOI: 10.3390/molecules27061919] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 12/25/2022] Open
Abstract
Pain is an essential modality of sensation in the body. Purinergic signaling plays an important role in nociceptive pain transmission, under both physiological and pathophysiological conditions, and is important for communication between both neuronal and non-neuronal cells. Microglia and astrocytes express a variety of purinergic effectors, and a variety of receptors play critical roles in the pathogenesis of neuropathic pain. In this review, we discuss our current knowledge of purinergic signaling and of the compounds that modulate purinergic transmission, with the aim of highlighting the importance of purinergic pathways as targets for the treatment of persistent pain.
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Affiliation(s)
- Hidetoshi Tozaki-Saitoh
- Department of Pharmacology, School of Pharmacy at Fukuoka, International University of Health and Welfare, 137-1 Enokizu, Okawa 831-8501, Japan;
- Correspondence: ; Tel.: +81-944-32-6137
| | - Hiroshi Takeda
- Department of Pharmacology, School of Pharmacy at Fukuoka, International University of Health and Welfare, 137-1 Enokizu, Okawa 831-8501, Japan;
| | - Kazuhide Inoue
- Institute for Advanced Study, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan;
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174
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Castillo C, Saez-Orellana F, Godoy PA, Fuentealba J. Microglial Activation Modulated by P2X4R in Ischemia and Repercussions in Alzheimer's Disease. Front Physiol 2022; 13:814999. [PMID: 35283778 PMCID: PMC8904919 DOI: 10.3389/fphys.2022.814999] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 01/12/2022] [Indexed: 01/01/2023] Open
Abstract
There are over 80 million people currently living who have had a stroke. The ischemic injury in the brain starts a cascade of events that lead to neuronal death, inducing neurodegeneration which could lead to Alzheimer's disease (AD). Cerebrovascular diseases have been suggested to contribute to AD neuropathological changes, including brain atrophy and accumulation of abnormal proteins such as amyloid beta (Aβ). In patients older than 60 years, the incidence of dementia a year after stroke was significantly increased. Nevertheless, the molecular links between stroke and dementia are not clearly understood but could be related to neuroinflammation. Considering that activated microglia has a central role, there are brain-resident innate immune cells and are about 10-15% of glial cells in the adult brain. Their phagocytic activity is essential for synaptic homeostasis in different areas, such as the hippocampus. These cells polarize into phenotypes or subtypes: the pro-inflammatory M1 phenotype, or the immunosuppressive M2 phenotype. Phenotype M1 is induced by classical activation, where microglia secrete a high level of pro- inflammatory factors which can cause damage to the surrounding neuronal cells. Otherwise, M2 phenotype is the major effector cell with the potential to counteract pro-inflammatory reactions and promote repair genes expression. Moreover, after the classical activation, an anti-inflammatory and a repair phase are initiated to achieve tissue homeostasis. Recently it has been described the concepts of homeostatic and reactive microglia and they had been related to major AD risk, linking to a multifunctional microglial response to Aβ plaques and pathophysiology markers related, such as intracellular increased calcium. The upregulation and increased activity of purinergic receptors activated by ADP/ATP, specially P2X4R, which has a high permeability to calcium and is mainly expressed in microglial cells, is observed in diseases related to neuroinflammation, such as neuropathic pain and stroke. Thus, P2X4R is associated with microglial activation. P2X4R activation drives microglia motility via the phosphatidylinositol-3-kinase (PI3K)/Akt pathway. Also, these receptors are involved in inflammatory-mediated prostaglandin E2 (PGE2) production and induce a secretion and increase the expression of BDNF and TNF-α which could be a link between pathologies related to aging and neuroinflammation.
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Affiliation(s)
- Carolina Castillo
- Laboratory of Screening of Neuroactive Compounds, Department of Physiology, School of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Francisco Saez-Orellana
- Laboratory of Screening of Neuroactive Compounds, Department of Physiology, School of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Pamela Andrea Godoy
- Laboratory of Screening of Neuroactive Compounds, Department of Physiology, School of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Jorge Fuentealba
- Laboratory of Screening of Neuroactive Compounds, Department of Physiology, School of Biological Sciences, Universidad de Concepción, Concepción, Chile
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Abstract
We aimed to investigate a sexually dimorphic role of calcitonin gene-related peptide (CGRP) in rodent models of pain. Based on findings in migraine where CGRP has a preferential pain-promoting effect in female rodents, we hypothesized that CGRP antagonists and antibodies would attenuate pain sensitization more efficaciously in female than male mice and rats. In hyperalgesic priming induced by activation of interleukin 6 signaling, CGRP receptor antagonists olcegepant and CGRP8-37 both given intrathecally, blocked, and reversed hyperalgesic priming only in females. A monoclonal antibody against CGRP, given systemically, blocked priming specifically in female rodents but failed to reverse it. In the spared nerve injury model, there was a transient effect of both CGRP antagonists, given intrathecally, on mechanical hypersensitivity in female mice only. Consistent with these findings, intrathecally applied CGRP caused a long-lasting, dose-dependent mechanical hypersensitivity in female mice but more transient effects in males. This CGRP-induced mechanical hypersensitivity was reversed by olcegepant and the KCC2 enhancer CLP257, suggesting a role for anionic plasticity in the dorsal horn in the pain-promoting effects of CGRP in females. In spinal dorsal horn slices, CGRP shifted GABAA reversal potentials to significantly more positive values, but, again, only in female mice. Therefore, CGRP may regulate KCC2 expression and/or activity downstream of CGRP receptors specifically in females. However, KCC2 hypofunction promotes mechanical pain hypersensitivity in both sexes because CLP257 alleviated hyperalgesic priming in male and female mice. We conclude that CGRP promotes pain plasticity in female rodents but has a limited impact in males.SIGNIFICANCE STATEMENT The majority of patients impacted by chronic pain are women. Mechanistic studies in rodents are creating a clear picture that molecular events promoting chronic pain are different in male and female animals. We sought to build on evidence showing that CGRP is a more potent and efficacious promoter of headache in female than in male rodents. To test this, we used hyperalgesic priming and the spared nerve injury neuropathic pain models in mice. Our findings show a clear sex dimorphism wherein CGRP promotes pain in female but not male mice, likely via a centrally mediated mechanism of action. Our work suggests that CGRP receptor antagonists could be tested for efficacy in women for a broader variety of pain conditions.
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176
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Zhao S, Wang F, Wang L, Xu Y, Lv L, Duan W, Bai R, Meng Z, Shao X. Involvement of the BDNF-TrkB-KCC2 pathway in neuropathic pain after brachial plexus avulsion. Brain Behav 2022; 12:e2464. [PMID: 35106976 PMCID: PMC8933754 DOI: 10.1002/brb3.2464] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/07/2021] [Accepted: 11/21/2021] [Indexed: 01/09/2023] Open
Abstract
INTRODUCTION Brachial plexus avulsion significantly increased brain-derived neurotrophic factor (BDNF) release in the spinal cord. Here we investigated the involvement of the BDNF-TrkB-KCC2 pathway in neuropathic pain caused by BPA injury. We hypothesized that activation of BDNF-TrkB may inhibit neuronal excitability by downregulating KCC2 to maintain a high intracellular Cl-concentration. We established a neuropathic pain rat model by avulsion of the lower trunk brachial plexus, and investigated the effects of the TrkB-specific antibody K-252a on the expression of BDNF, TrkB, and KCC2. METHODS We randomly divided 40 male SD rats into four groups. In the brachial plexus avulsion group, C8-T1 roots were avulsed from the spinal cord at the lower trunk level. In the K252a group, 5uL K252a was applied intrathecally daily for three days after avulsion. In the sham surgery group, expose only and without damage. The control group did not undergo any treatment. Mechanical hyperalgesia and cold allodynia were analyzed by electronic pain measuring instrument and acetone spray method at different time points on days 1, 3, 7, 10, 14, and 21 after surgery. At 21 days after surgery, the expression of BDNF and TrkB in dorsal horn neurons and GFAP in astrocytes were detected by immunohistochemistry at the C5-T1 segment of the spinal cord. The expression levels of BDNF, TrkB, and KCC2 in the C5-T1 spinal cord were measured by Western Blot at 7 and 21 days. RESULTS Mechanical hyperalgesia and cold allodynia were significantly reduced in the K252a group compared with the brachial plexus avulsion group. Compared with the BPA group, BDNF, TrkB and GFAP were significantly decreased in the K252a group at 21 days after treatment by immunohistochemical test. In the WB test, the expressions of BDNF and TrkB in the K252a group were quantitatively detected to be decreased, while the expression of KCC2 was increased, which was obvious at 7 and 21 days. CONCLUSION BDNF-TrkB-KCC2 pathway can significantly relieve neuropathic pain after BPA, and is a potential target for the treatment of neuropathic pain.
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Affiliation(s)
- Shuo Zhao
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
- Orthopaedic DepartmentChildren's Hospital of Hebei ProvinceShijiazhuangChina
| | - Fengyu Wang
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
| | - Li Wang
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
| | - Yali Xu
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
| | - Li Lv
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
| | - Wenxu Duan
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
| | - Runze Bai
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
| | - Zhao Meng
- Orthopaedic DepartmentChildren's Hospital of Hebei ProvinceShijiazhuangChina
| | - Xinzhong Shao
- Department of Hand SurgeryThe Third Hospital of Hebei Medical UniversityShijiazhuangChina
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177
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Okumo T, Takayama Y, Maruyama K, Kato M, Sunagawa M. Senso-Immunologic Prospects for Complex Regional Pain Syndrome Treatment. Front Immunol 2022; 12:786511. [PMID: 35069559 PMCID: PMC8767061 DOI: 10.3389/fimmu.2021.786511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Complex regional pain syndrome (CRPS) is a chronic pain syndrome that occurs in tissue injuries as the result of surgery, trauma, or ischemia. The clinical features of this severely painful condition include redness and swelling of the affected skin. Intriguingly, it was recently suggested that transient receptor potential ankyrin 1 (TRPA1) is involved in chronic post-ischemia pain, a CRPS model. TRPA1 is a non-selective cation channel expressed in calcitonin gene-related peptide (CGRP)-positive primary nociceptors that becomes highly activated in ischemic conditions, leading to the generation of pain. In this review, we summarize the history of TRPA1 and its involvement in pain sensation, inflammation, and CRPS. Furthermore, bone atrophy is also thought to be a characteristic clinical sign of CRPS. The altered bone microstructure of CRPS patients is thought to be caused by aggravated bone resorption via enhanced osteoclast differentiation and activation. Although TRPA1 could be a target for pain treatment in CRPS patients, we also discuss the paradoxical situation in this review. Nociceptor activation decreases the risk of bone destruction via CGRP secretion from free nerve endings. Thus, TRPA1 inhibition could cause severe bone atrophy. However, the suitable therapeutic strategy is controversial because the pathologic mechanisms of bone atrophy in CRPS are unclear. Therefore, we propose focusing on the remission of abnormal bone turnover observed in CRPS using a recently developed concept: senso-immunology.
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Affiliation(s)
- Takayuki Okumo
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan
| | - Yasunori Takayama
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan
| | - Kenta Maruyama
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan.,Division of Cell Signaling, National Institute for Physiological Sciences, Natural Institutes for Natural Sciences, Okazaki, Japan
| | - Mami Kato
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan.,Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Masataka Sunagawa
- Department of Physiology, Showa University School of Medicine, Shinagawa, Japan
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178
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赵 佳, 杨 荷, 王 招, 朱 海, 谢 敏. [ANA- 12 inhibits spinal inflammation and alleviates acute and chronic pain in rats by targeted blocking of BDNF/TrkB signaling]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2022; 42:232-237. [PMID: 35365447 PMCID: PMC8983361 DOI: 10.12122/j.issn.1673-4254.2022.02.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To investigate the inhibitory effect of ANA-12 that blocks brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrkB) signaling on inflammatory pain in rats and explore the underlying mechanism. METHODS Forty-two adult SD rats were randomized into BDNF-induced acute pain group (n=24) and CFA-induced chronic pain group. The former group were randomly divided into 4 subgroups, including a control group, ANA-12 treatment group, BDNF treatment group, and BDNF+ANA-12 treatment group; the latter group were subgrouped into control group, CFA treatment group (CFA) and CFA + ANA-12 treatment group. The effects of ANA-12 treatment on pain behaviors of the rats with BDNF-induced acute pain and CFA-induced chronic inflammatory pain were observed. Western blotting was used to examine TrkB signaling and expressions of microglia marker protein Iba1 and TNF-α in the spinal cord of the rats. RESULTS BDNF injection into the subarachnoid space significantly increased the number of spontaneous paw withdrawal of the rats (P < 0.05), which was obviously reduced by ANA-12 treatment (P < 0.05). The rats with intraplantar injection of CFA, showed significantly increased ipsilateral mechanical stimulation sensitivity (P < 0.05), and ANA-12 treatment obviously increased the ipsilateral foot withdrawal threshold (P < 0.05). Treatment with either BDNF or CFA significantly increased the phosphorylation level of TrkB (Y705) in the spinal cord of the rats (P < 0.05), which was significantly lowered by ANA-12 treatment (P < 0.05). Treatment with BDNF and CFA both significantly up-regulated the expressions of Iba1 and TNF-α in the spinal cord (P < 0.05), but ANA-12 significantly reduced their expression levels (P < 0.05). CONCLUSION ANA-12 can reduce spinal cord inflammation and relieve acute and chronic pain in rats by targeted blocking of BDNF/TrkB signaling.
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Affiliation(s)
- 佳佳 赵
- />湖北科技学院药学院,湖北 咸宁 437100School of Pharmacy, Hubei University of Science and Technology, Xianning 437100, China
| | - 荷雨 杨
- />湖北科技学院药学院,湖北 咸宁 437100School of Pharmacy, Hubei University of Science and Technology, Xianning 437100, China
| | - 招娣 王
- />湖北科技学院药学院,湖北 咸宁 437100School of Pharmacy, Hubei University of Science and Technology, Xianning 437100, China
| | - 海丽 朱
- />湖北科技学院药学院,湖北 咸宁 437100School of Pharmacy, Hubei University of Science and Technology, Xianning 437100, China
| | - 敏 谢
- />湖北科技学院药学院,湖北 咸宁 437100School of Pharmacy, Hubei University of Science and Technology, Xianning 437100, China
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179
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L-Thyroxine Improves Vestibular Compensation in a Rat Model of Acute Peripheral Vestibulopathy: Cellular and Behavioral Aspects. Cells 2022; 11:cells11040684. [PMID: 35203333 PMCID: PMC8869897 DOI: 10.3390/cells11040684] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023] Open
Abstract
Unilateral vestibular lesions induce a vestibular syndrome, which recovers over time due to vestibular compensation. The therapeutic effect of L-Thyroxine (L-T4) on vestibular compensation was investigated by behavioral testing and immunohistochemical analysis in a rat model of unilateral vestibular neurectomy (UVN). We demonstrated that a short-term L-T4 treatment reduced the vestibular syndrome and significantly promoted vestibular compensation. Thyroid hormone receptors (TRα and TRβ) and type II iodothyronine deiodinase (DIO2) were present in the vestibular nuclei (VN), supporting a local action of L-T4. We confirmed the T4-induced metabolic effects by demonstrating an increase in the number of cytochrome oxidase-labeled neurons in the VN three days after the lesion. L-T4 treatment modulated glial reaction by decreasing both microglia and oligodendrocytes in the deafferented VN three days after UVN and increased cell proliferation. Survival of newly generated cells in the deafferented vestibular nuclei was not affected, but microglial rather than neuronal differentiation was favored by L-T4 treatment.
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180
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Fauss GNK, Hudson KE, Grau JW. Role of Descending Serotonergic Fibers in the Development of Pathophysiology after Spinal Cord Injury (SCI): Contribution to Chronic Pain, Spasticity, and Autonomic Dysreflexia. BIOLOGY 2022; 11:234. [PMID: 35205100 PMCID: PMC8869318 DOI: 10.3390/biology11020234] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 12/12/2022]
Abstract
As the nervous system develops, nerve fibers from the brain form descending tracts that regulate the execution of motor behavior within the spinal cord, incoming sensory signals, and capacity to change (plasticity). How these fibers affect function depends upon the transmitter released, the receptor system engaged, and the pattern of neural innervation. The current review focuses upon the neurotransmitter serotonin (5-HT) and its capacity to dampen (inhibit) neural excitation. A brief review of key anatomical details, receptor types, and pharmacology is provided. The paper then considers how damage to descending serotonergic fibers contributes to pathophysiology after spinal cord injury (SCI). The loss of serotonergic fibers removes an inhibitory brake that enables plasticity and neural excitation. In this state, noxious stimulation can induce a form of over-excitation that sensitizes pain (nociceptive) circuits, a modification that can contribute to the development of chronic pain. Over time, the loss of serotonergic fibers allows prolonged motor drive (spasticity) to develop and removes a regulatory brake on autonomic function, which enables bouts of unregulated sympathetic activity (autonomic dysreflexia). Recent research has shown that the loss of descending serotonergic activity is accompanied by a shift in how the neurotransmitter GABA affects neural activity, reducing its inhibitory effect. Treatments that target the loss of inhibition could have therapeutic benefit.
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Affiliation(s)
| | | | - James W. Grau
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX 77843, USA; (G.N.K.F.); (K.E.H.)
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181
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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
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182
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The Role of ATP Receptors in Pain Signaling. Neurochem Res 2022; 47:2454-2468. [DOI: 10.1007/s11064-021-03516-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/11/2021] [Accepted: 12/22/2021] [Indexed: 12/21/2022]
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183
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Madaan P, Behl T, Sehgal A, Singh S, Sharma N, Yadav S, Kaur S, Bhatia S, Al-Harrasi A, Abdellatif AAH, Ashraf GM, Abdel-Daim MM, Dailah HG, Anwer MK, Bungau S. Exploring the Therapeutic Potential of Targeting Purinergic and Orexinergic Receptors in Alcoholic Neuropathy. Neurotox Res 2022; 40:646-669. [DOI: 10.1007/s12640-022-00477-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 12/11/2022]
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184
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Abstract
The wingless-related integration site (Wnt) signaling pathway plays an essential role in embryonic development and nervous system regulation. It is critically involved in multiple types of neuropathic pain (NP), such as HIV-related NP, cancer pain, diabetic neuralgia, multiple sclerosis-related NP, endometriosis pain, and other painful diseases. Wnt signaling is also implicated in the pain induced by sciatic nerve compression injury and selective spinal nerve ligation. Thus, the Wnt signaling pathway may be a potential therapeutic target for NP.
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185
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Porter GA, O’Connor JC. Brain-derived neurotrophic factor and inflammation in depression: Pathogenic partners in crime? World J Psychiatry 2022; 12:77-97. [PMID: 35111580 PMCID: PMC8783167 DOI: 10.5498/wjp.v12.i1.77] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/21/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023] Open
Abstract
Major depressive disorder is a debilitating disorder affecting millions of people each year. Brain-derived neurotrophic factor (BDNF) and inflammation are two prominent biologic risk factors in the pathogenesis of depression that have received considerable attention. Many clinical and animal studies have highlighted associations between low levels of BDNF or high levels of inflammatory markers and the development of behavioral symptoms of depression. However, less is known about potential interaction between BDNF and inflammation, particularly within the central nervous system. Emerging evidence suggests that there is bidirectional regulation between these factors with important implications for the development of depressive symptoms and anti-depressant response. Elevated levels of inflammatory mediators have been shown to reduce expression of BDNF, and BDNF may play an important negative regulatory role on inflammation within the brain. Understanding this interaction more fully within the context of neuropsychiatric disease is important for both developing a fuller understanding of biological pathogenesis of depression and for identifying novel therapeutic opportunities. Here we review these two prominent risk factors for depression with a particular focus on pathogenic implications of their interaction.
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Affiliation(s)
- Grace A Porter
- Department of Pharmacology, UT Health San Antonio, San Antonio, TX 78229, United States
| | - Jason C O’Connor
- Department of Pharmacology, University of Texas Health San Antonio, San Antonio, TX 78229, United States
- Audie L. Murphy VA Hospital, South Texas Veterans Health System, San Antonio, TX 78229, United States
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186
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Shinozaki C, Kohno K, Shiroishi M, Takahashi D, Yoshikawa Y, Abe Y, Hamase K, Nakakido M, Tsumoto K, Inoue K, Tsuda M, Ueda T. Improvement of the affinity of an anti-rat P2X4 receptor antibody by introducing electrostatic interactions. Sci Rep 2022; 12:131. [PMID: 34996944 PMCID: PMC8742113 DOI: 10.1038/s41598-021-03784-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 12/09/2021] [Indexed: 11/30/2022] Open
Abstract
We have recently developed a mouse monoclonal antibody (12-10H) binding to the head domain region in rat P2X4 receptor (rP2X4R, which is crucial for the pathogenesis of neuropathic pain) expressed on the cell with the highest binding affinity (KD = 20 nM). However, the 12-10H antibody failed to detect endogenously expressed P2X4Rs in microglia isolated from the spinal cord of rats whose spinal nerves were injured. Then, we prepared R5 mutant, in which five arginine residues were introduced into variable regions except for the "hot spot" in the 12-10H antibody to increase electrostatic interactions with the head domain, an anionic region, in rP2X4R. The mutation resulted in an increase of 50-fold in the affinity of the R5 mutant for the head domain with respect to the intact 12-10H antibody. As a result, detection of P2X4Rs endogenously expressed on primary cultured microglial cells originated from the neonatal rat brain and spinal cord microglia isolated from a rat model of neuropathic pain was achieved. These findings suggest a strategy to improve the affinity of a monoclonal antibody for an anionic antigen by the introduction of several arginine residues into variable regions other than the "hot spot" in the paratope.
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Grants
- JP26293129 Japan Society for the Promotion of Science
- JP26293129 Japan Society for the Promotion of Science
- JP26293129 Japan Society for the Promotion of Science
- JP16H02420, JP19H05766, and JP20H02531 Japan Society for the Promotion of Science
- JP16H02420, JP19H05766, and JP20H02531 Japan Society for the Promotion of Science
- JP26293129 Japan Society for the Promotion of Science
- JP21am0101091 Japan Agency for Medical Research and Development
- JP21am0101091 Japan Agency for Medical Research and Development
- JP21am0101091 Japan Agency for Medical Research and Development
- JP18am0101094j, JP18dm0107064h, JP18mk0101081h, JP18fm0208030h, JP18fk0108073h, and JP18ak0101100h Japan Agency for Medical Research and Development
- JP18am0101094j, JP18dm0107064h, JP18mk0101081h, JP18fm0208030h, JP18fk0108073h, and JP18ak0101100h Japan Agency for Medical Research and Development
- JP21am0101091 Japan Agency for Medical Research and Development
- JP21am0101091 Japan Agency for Medical Research and Development
- JPMJCR20H8 the JST CREST
- JPMJCR20H8 the JST CREST
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Affiliation(s)
- Chinatsu Shinozaki
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Keita Kohno
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan
| | - Mitsunori Shiroishi
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku Katsushika-ku, Tokyo, 125-8585, Japan
| | - Daisuke Takahashi
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yu Yoshikawa
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan
| | - Yoshito Abe
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Kenji Hamase
- Department of Drug Discovery and Evolution, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Makoto Nakakido
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Kohei Tsumoto
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Kazuhide Inoue
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan.
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan.
| | - Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan.
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan.
| | - Tadashi Ueda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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187
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Rahmani N, Mohammadi M, Manaheji H, Maghsoudi N, Katinger H, Baniasadi M, Zaringhalam J. Carbamylated erythropoietin improves recognition memory by modulating microglia in a rat model of pain. Behav Brain Res 2022; 416:113576. [PMID: 34506840 DOI: 10.1016/j.bbr.2021.113576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 09/04/2021] [Accepted: 09/04/2021] [Indexed: 11/18/2022]
Abstract
Patients with chronic pain often complain about memory impairments. Experimental studies have shown neuroprotective effects of Carbamylated erythropoietin (Cepo-Fc) in the treatment of cognitive dysfunctions. However, little is currently known about its precise molecular mechanisms in a model of inflammatory pain. Therefore, this study aimed to investigate neuroprotective effects of Cepo-Fc against cognitive impairment induced by the inflammatory model of Complete Freund's Adjuvant (CFA). Carbamylated erythropoietin was administrated Intraperitoneally (i.p) on the day CFA injection, continued for a 21-days period. After conducting the behavioral tests (thermal hyperalgesia and novel object recognition test), western blot and ELISA were further preformed on days 0, 7, and 21. The results of this study indicate that Cepo-Fc can effectively reverse the CFA induced thermal hyperalgesia and recognition memory impairment. Additionally, Cepo-Fc noticeably decreased the hippocampal microglial expression, production of hippocampal IL-1β, and hippocampal apoptosis and necroptosis induced by the inflammatory pain. Therefore, our findings suggest that neuroprotective effects of Cepo-Fc in the treatment of pain related recognition memory impairment may be mediated through reducing hippocampal microglial expression as well as IL-1β production.
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Affiliation(s)
- Nasser Rahmani
- Physiology Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mola Mohammadi
- Physiology Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Homa Manaheji
- Physiology Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nader Maghsoudi
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hermann Katinger
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Mansoureh Baniasadi
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Jalal Zaringhalam
- Physiology Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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188
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van den Hoogen NJ, Harding EK, Davidson CED, Trang T. Cannabinoids in Chronic Pain: Therapeutic Potential Through Microglia Modulation. Front Neural Circuits 2022; 15:816747. [PMID: 35069129 PMCID: PMC8777271 DOI: 10.3389/fncir.2021.816747] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/17/2021] [Indexed: 12/16/2022] Open
Abstract
Chronic pain is a complex sensory, cognitive, and emotional experience that imposes a great personal, psychological, and socioeconomic burden on patients. An estimated 1.5 billion people worldwide are afflicted with chronic pain, which is often difficult to treat and may be resistant to the potent pain-relieving effects of opioid analgesics. Attention has therefore focused on advancing new pain therapies directed at the cannabinoid system because of its key role in pain modulation. Endocannabinoids and exogenous cannabinoids exert their actions primarily through Gi/o-protein coupled cannabinoid CB1 and CB2 receptors expressed throughout the nervous system. CB1 receptors are found at key nodes along the pain pathway and their activity gates both the sensory and affective components of pain. CB2 receptors are typically expressed at low levels on microglia, astrocytes, and peripheral immune cells. In chronic pain states, there is a marked increase in CB2 expression which modulates the activity of these central and peripheral immune cells with important consequences for the surrounding pain circuitry. Growing evidence indicate that interventions targeting CB1 or CB2 receptors improve pain outcomes in a variety of preclinical pain models. In this mini-review, we will highlight recent advances in understanding how cannabinoids modulate microglia function and its implications for cannabinoid-mediated analgesia, focusing on microglia-neuron interactions within the spinal nociceptive circuitry.
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Affiliation(s)
- Nynke J. van den Hoogen
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Erika K. Harding
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Chloé E. D. Davidson
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Tuan Trang
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Tuan Trang
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189
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Cherubini E, Di Cristo G, Avoli M. Dysregulation of GABAergic Signaling in Neurodevelomental Disorders: Targeting Cation-Chloride Co-transporters to Re-establish a Proper E/I Balance. Front Cell Neurosci 2022; 15:813441. [PMID: 35069119 PMCID: PMC8766311 DOI: 10.3389/fncel.2021.813441] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/30/2021] [Indexed: 01/01/2023] Open
Abstract
The construction of the brain relies on a series of well-defined genetically and experience- or activity -dependent mechanisms which allow to adapt to the external environment. Disruption of these processes leads to neurological and psychiatric disorders, which in many cases are manifest already early in postnatal life. GABA, the main inhibitory neurotransmitter in the adult brain is one of the major players in the early assembly and formation of neuronal circuits. In the prenatal and immediate postnatal period GABA, acting on GABAA receptors, depolarizes and excites targeted cells via an outwardly directed flux of chloride. In this way it activates NMDA receptors and voltage-dependent calcium channels contributing, through intracellular calcium rise, to shape neuronal activity and to establish, through the formation of new synapses and elimination of others, adult neuronal circuits. The direction of GABAA-mediated neurotransmission (depolarizing or hyperpolarizing) depends on the intracellular levels of chloride [Cl−]i, which in turn are maintained by the activity of the cation-chloride importer and exporter KCC2 and NKCC1, respectively. Thus, the premature hyperpolarizing action of GABA or its persistent depolarizing effect beyond the postnatal period, leads to behavioral deficits associated with morphological alterations and an excitatory (E)/inhibitory (I) imbalance in selective brain areas. The aim of this review is to summarize recent data concerning the functional role of GABAergic transmission in building up and refining neuronal circuits early in development and its dysfunction in neurodevelopmental disorders such as Autism Spectrum Disorders (ASDs), schizophrenia and epilepsy. In particular, we focus on novel information concerning the mechanisms by which alterations in cation-chloride co-transporters (CCC) generate behavioral and cognitive impairment in these diseases. We discuss also the possibility to re-establish a proper GABAA-mediated neurotransmission and excitatory (E)/inhibitory (I) balance within selective brain areas acting on CCC.
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Affiliation(s)
- Enrico Cherubini
- European Brain Research Institute (EBRI)-Rita Levi-Montalcini, Roma, Italy
- *Correspondence: Enrico Cherubini
| | - Graziella Di Cristo
- Neurosciences Department, Université de Montréal and CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology and Neurosurgery and of Physiology, McGill University, Montreal, QC, Canada
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190
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Suzuki T, Tanaka KF. Downregulation of Bdnf Expression in Adult Mice Causes Body Weight Gain. Neurochem Res 2022; 47:2645-2655. [PMID: 34982395 DOI: 10.1007/s11064-021-03523-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/20/2021] [Accepted: 12/28/2021] [Indexed: 10/19/2022]
Abstract
Gain or loss of appetite and resulting body weight changes are commonly observed in major depressive disorders (MDDs). Brain-derived neurotrophic factor (BDNF) is broadly expressed in the brain and is thought to play a role in the pathophysiology of MDDs and obesity. Congenital loss of function of BDNF causes weight gain in both humans and rodents; however, it is not clear whether acquired loss of function of BDNF also affects body weight. Thus, we exploited mutant mice in which the Bdnf expression level is regulated by the tetracycline-dependent transcriptional silencer (tTS)-tetracycline operator sequence (tetO) system. Time-controlled Bdnf expression using this system allowed us to establish congenital and acquired loss of function of Bdnf in mice. We demonstrated that changes in Bdnf expression influenced body weight during not only the developmental stage but also the adult stage of mice. Although it is still unclear whether acquired Bdnf loss of function in rodents mimics the pathology of MDD, our findings may bridge the mechanistic gap between MDDs and body weight gain in line with BDNF dysfunction.
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Affiliation(s)
- Toru Suzuki
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
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191
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Wang ZB, Liu YD, Wang S, Zhao P. High-frequency spinal cord stimulation produces long-lasting analgesic effects by restoring lysosomal function and autophagic flux in the spinal dorsal horn. Neural Regen Res 2022; 17:370-377. [PMID: 34269212 PMCID: PMC8463971 DOI: 10.4103/1673-5374.317989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
High-frequency spinal cord stimulation (HF-SCS) has been established as an effective therapy for neuropathic pain. However, the analgesic mechanisms involved in HF-SCS remain to be clarified. In our study, adult rat neuropathic pain was induced by spinal nerve ligation. Two days after modeling, the rats were subjected to 4 hours of HF-SCS (motor threshold 50%, frequency 10,000 Hz, and pulse width 0.024 ms) in the dorsal horn of the spinal cord. The results revealed that the tactile allodynia of spinal nerve-injured rats was markedly alleviated by HF-SCS, and the effects were sustained for 3 hours after the stimulation had ceased. HF-SCS restored lysosomal function, increased the levels of lysosome-associated membrane protein 2 (LAMP2) and the mature form of cathepsin D (matu-CTSD), and alleviated the abnormally elevated levels of microtubule-associated protein 1A/B-light chain 3 (LC3)-II and sequestosome 1 (P62) in spinal nerve-injured rats. HF-SCS also mostly restored the immunoreactivity of LAMP2, which was localized in neurons in the superficial layers of the spinal dorsal horn in spinal nerve-injured rats. In addition, intraperitoneal administration of 15 mg/kg chloroquine for 60 minutes reversed the expression of the aforementioned proteins and shortened the timing of the analgesic effects of HF-SCS. These findings suggest that HF-SCS may exhibit long-lasting analgesic effects on neuropathic pain in rats through improving lysosomal dysfunction and alleviating autophagic flux. This study was approved by the Laboratory Animal Ethics Committee of China Medical University, Shenyang, China (approval No. 2017PS196K) on March 1, 2017.
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Affiliation(s)
- Zhi-Bin Wang
- Department of Anesthesiology and Pain Management, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Yong-Da Liu
- Department of Anesthesiology and Pain Management, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Shuo Wang
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ping Zhao
- Department of Anesthesiology and Pain Management, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, China
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192
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Dworsky-Fried Z, Faig CA, Vogel HA, Kerr BJ, Taylor AMW. Central amygdala inflammation drives pain hypersensitivity and attenuates morphine analgesia in experimental autoimmune encephalomyelitis. Pain 2022; 163:e49-e61. [PMID: 33863858 DOI: 10.1097/j.pain.0000000000002307] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/23/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Chronic pain is a highly prevalent symptom associated with the autoimmune disorder multiple sclerosis (MS). The central nucleus of the amygdala plays a critical role in pain processing and modulation. Neuropathic pain alters nociceptive signaling in the central amygdala, contributing to pain chronicity and opioid tolerance. Here, we demonstrate that activated microglia within the central amygdala disrupt nociceptive sensory processing and contribute to pain hypersensitivity in experimental autoimmune encephalomyelitis (EAE), the most frequently used animal model of MS. Male and female mice with EAE exhibited differences in microglial morphology in the central amygdala, which was associated with heat hyperalgesia, impaired morphine reward, and reduced morphine antinociception in females. Animals with EAE displayed a lack of morphine-evoked activity in cells expressing somatostatin within the central amygdala, which drive antinociception. Induction of focal microglial activation in naïve mice via injection of lipopolysaccharide into the central amygdala produced a loss of morphine analgesia in females, similar to as observed in EAE animals. Our data indicate that activated microglia within the central amygdala may contribute to the sexually dimorphic effects of morphine and may drive neuronal adaptations that lead to pain hypersensitivity in EAE. Our results provide a possible mechanism underlying the decreased efficacy of opioid analgesics in the management of MS-related pain, identifying microglial activation as a potential therapeutic target for pain symptoms in this patient population.
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Affiliation(s)
- Zoë Dworsky-Fried
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Christian A Faig
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Holly A Vogel
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Bradley J Kerr
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada
| | - Anna M W Taylor
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada
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193
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Ye D, Fairchild TJ, Vo L, Drummond PD. Painful diabetic peripheral neuropathy: Role of oxidative stress and central sensitisation. Diabet Med 2022; 39:e14729. [PMID: 34674302 DOI: 10.1111/dme.14729] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 10/20/2021] [Indexed: 12/22/2022]
Abstract
AIMS Diabetic peripheral neuropathy (DPN) occurs in about half of people with diabetes, of whom a quarter may develop chronic pain. Pain may remain for years yet be difficult to treat because the underlying mechanisms remain unclear. There is consensus that processing excessive glucose leads to oxidative stress, interfering with normal metabolism. In this narrative review, we argue that oxidative stress may also contribute to pain. METHODS We reviewed literature in PubMed published between January 2005 and August 2021. RESULTS AND CONCLUSIONS In diabetes, hyperglycaemia and associated production of reactive species can directly increase pain signalling and activate sensory neurons; or the effects can be indirect, mediated by mitochondrial damage and enhanced inflammation. Furthermore, pain processing in the central nervous system is compromised in painful DPN. This is implicated in central sensitisation and dysfunctional pain modulation. However, central pain modulatory function is understudied in diabetes. Future research is required to clarify whether central sensitisation and/or disturbances in central pain modulation contribute to painful DPN. Positive results would facilitate early detection and future treatment.
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Affiliation(s)
- Di Ye
- Discipline of Psychology and Healthy Ageing Research Centre, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
| | - Timothy J Fairchild
- Discipline of Exercise Science and Healthy Ageing Research Centre, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
| | - Lechi Vo
- Discipline of Psychology and Healthy Ageing Research Centre, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
| | - Peter D Drummond
- Discipline of Psychology and Healthy Ageing Research Centre, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
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194
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Kimura Y, Hayashi Y, Hitomi S, Ikutame D, Urata K, Shibuta I, Sakai A, Ni J, Iwata K, Tonogi M, Shinoda M. IL-33 induces orofacial neuropathic pain through Fyn-dependent phosphorylation of GluN2B in the trigeminal spinal subnucleus caudalis. Brain Behav Immun 2022; 99:266-280. [PMID: 34715301 DOI: 10.1016/j.bbi.2021.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Orofacial neuropathic pain can cause considerable disruptions in patients' daily lives, especially because of a lack of effective medications as its underlying causative mechanisms are not fully understood. Here, we found neuron-specific expression of the interleukin (IL)-33 receptor in the trigeminal spinal subnucleus caudalis (Vc), distinct from the spinal dorsal horn. Reduction in head withdrawal threshold in response to von Frey filament stimulation of the whisker pad skin was inversely correlated with the upregulation of IL-33 in the Vc after infraorbital nerve injury (IONI). Neutralization of IL-33 in the Vc alleviated mechanical allodynia in the whisker pad skin after IONI; conversely, intracisternal administration of IL-33 elicited mechanical allodynia in the whisker pad skin, which was relieved by GluN2B antagonism. Moreover, IL-33 triggered the potentiation of GluN2B-containing N-methyl-D-aspartate receptor-mediated synaptic currents and phosphorylation of synaptosomal GluN2B in the Vc, whereas IONI-induced GluN2B phosphorylation was inhibited by neutralization of IL-33 in the Vc. IL-33-induced GluN2B phosphorylation was mediated by phosphorylation of Fyn kinase, and inhibition of the Fyn kinase pathway prevented the development of IL-33-induced mechanical allodynia. Our findings provide insights into a new mechanism by which IL-33 directly regulates synaptic transmission and suggest that IL-33 signaling could be a candidate target for therapeutic interventions for orofacial neuropathic pain.
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Affiliation(s)
- Yuki Kimura
- Department of Oral and Maxillofacial Surgery, Nihon University School of Dentistry, Tokyo, Japan
| | - Yoshinori Hayashi
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan.
| | - Suzuro Hitomi
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Daisuke Ikutame
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Kentaro Urata
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Ikuko Shibuta
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Atsushi Sakai
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy in the Ministry of Industry and Information Technology, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Morio Tonogi
- Department of Oral and Maxillofacial Surgery, Nihon University School of Dentistry, Tokyo, Japan
| | - Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
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195
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Systemic LPS-induced microglial activation results in increased GABAergic tone: A mechanism of protection against neuroinflammation in the medial prefrontal cortex in mice. Brain Behav Immun 2022; 99:53-69. [PMID: 34582995 DOI: 10.1016/j.bbi.2021.09.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/19/2021] [Accepted: 09/21/2021] [Indexed: 02/01/2023] Open
Abstract
Neuroinflammation with excess microglial activation and synaptic dysfunction are early symptoms of most neurological diseases. However, how microglia-associated neuroinflammation regulates synaptic activity remains obscure. We report here that acute neuroinflammation induced by intraperitoneal injection of lipopolysaccharide (LPS) results in cell-type-specific increases in inhibitory postsynaptic currents in the glutamatergic, but not the GABAergic, neurons of medial prefrontal cortex (mPFC), coinciding with excessive microglial activation. LPS causes upregulation in levels of GABAAR subunits, glutamine synthetase and vesicular GABA transporter, and downregulation in brain-derived neurotrophic factor (BDNF) and its receptor, pTrkB. Blockage of microglial activation by minocycline ameliorates LPS-induced abnormal expression of GABA signaling-related proteins and activity of synaptic and network. Moreover, minocycline prevents the mice from LPS-induced aberrant behavior, such as a reduction in total distance and time spent in the centre in the open field test; decreases in entries into the open arm of elevated-plus maze and in consumption of sucrose; increased immobility in the tail suspension test. Furthermore, upregulation of GABA signaling by tiagabine also prevents LPS-induced microglial activation and aberrant behavior. This study illustrates a mode of bidirectional constitutive signaling between the neural and immune compartments of the brain, and suggests that the mPFC is an important area for brain-immune system communication. Moreover, the present study highlights GABAergic signaling as a key therapeutic target for mitigating neuroinflammation-induced abnormal synaptic activity in the mPFC, together with the associated behavioral abnormalities.
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196
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Yin Y, Li H, Wang J, Kong Y, Chang J, Chu G. Implication of microglia in ketamine-induced long-term cognitive impairment in murine pups. Hum Exp Toxicol 2022; 41:9603271221128739. [PMID: 36172893 DOI: 10.1177/09603271221128739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Ketamine, a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist, is widely applicable to anesthesia, analgesia, and sedation. However, the function and mechanisms of ketamine in the long-term learning and memory function of neonatal mice are unclear. OBJECTIVE The present study aims to investigate whether long-term learning and memory function will be affected by multiple ketamine exposures in the early development period. METHODS The mRNA and protein levels were measured by RT-qPCR and western blot, respectively. The Morris Water Maze test was performed to assess spatial learning and memory. RESULTS We identified that neonatal exposure to ketamine downsized the positive neurons for microtubule-associated protein doublecortin (DCX) and Ki67 in hippocampal dentate gyrus at the juvenile and late adolescence stages. Double-labeling tests demonstrated that the counts of Iba1+ cells and Ki67+ cells were pronouncedly diminished with exposure to ketamine. Further, qPCR assays to screen the key factors predisposing the populations and maturation of microglia exhibited remarkable decline of CX3CR1 mRNA levels in ketamine group versus the control group. The close relation of microglia to synaptic plasticity was depicted by the significantly downregulated synaptic plasticity-related proteins NR2B and PSD-95 subsequent to multiple exposures to ketamine. Finally, we found that both the protein and mRNA levels of BDNF were markedly decreased in ketamine group versus the control group. CONCLUSION We found that multiple exposures to ketamine in neonatal mice lead to spatial learning and memory dysfunction. The alterations of microglial development and function are the possible mechanisms of long-term learning and memory impairment.
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Affiliation(s)
- Y Yin
- Department of Anesthesiology, 117851Changzhou Maternity and Child Health Care Hospital, Changzhou, China
| | - H Li
- Department of Anesthesiology, 66322Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - J Wang
- Department of Anesthesiology, 56695Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Y Kong
- Department of Anesthesiology, 117851Changzhou Maternity and Child Health Care Hospital, Changzhou, China
| | - J Chang
- Department of Anesthesiology, 117851Changzhou Maternity and Child Health Care Hospital, Changzhou, China
| | - G Chu
- Department of Anesthesiology, 117851Changzhou Maternity and Child Health Care Hospital, Changzhou, China
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197
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Koyanagi S, Kusunose N, Yasukochi S, Ohdo S. Basis for diurnal exacerbation of neuropathic pain hypersensitivity and its application for drug development. J Biochem 2021; 171:487-492. [PMID: 34967399 DOI: 10.1093/jb/mvab143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/13/2021] [Indexed: 11/14/2022] Open
Abstract
In addition to diurnal rhythms in physiology and behavior, a variety of pathological conditions also exhibit marked day-night changes in symptom intensity, exemplified by allergic rhinitis, arthritis, asthma, myocardial infarction, congestive heart failure, stroke, and chronic pain disorders. Currently, novel therapeutic approaches are facilitated by the development of chemical compounds targeted to key proteins that cause diurnal exacerbation of pathological events. Neuropathic pain is a chronic condition that occurs by tumor-induced nerve compression, cancer cell infiltration into the nerve, diabetes, and herpes virus infection. One troublesome hallmark symptom of neuropathic pain is hypersensitivity to normally innocuous stimuli known as "mechanical allodynia" that is often refractory to common analgesic therapies. Millions of patients worldwide presently endure neuropathic pain. We summarize the recent insights gained into the mechanism of diurnal exacerbation of neuropathic pain hypersensitivity and introduce the strategy of circadian clock-based drug development.
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Affiliation(s)
- Satoru Koyanagi
- Faculty of Pharmaceutical Sciences, Kyushu University; 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Naoki Kusunose
- Faculty of Pharmaceutical Sciences, Kyushu University; 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Sai Yasukochi
- Faculty of Pharmaceutical Sciences, Kyushu University; 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shigehiro Ohdo
- Faculty of Pharmaceutical Sciences, Kyushu University; 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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198
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Grieder TE, Yee M, Vargas-Perez H, Maal-Bared G, George S, Ting-A-Kee R, George O, van der Kooy D. Administration of brain-derived neurotrophic factor in the ventral tegmental area produces a switch from a nicotine nondependent D1R-mediated motivational state to a nicotine dependent-like D2R-mediated motivational state. Eur J Neurosci 2021; 55:714-724. [PMID: 34963197 DOI: 10.1111/ejn.15579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 12/15/2021] [Accepted: 12/21/2021] [Indexed: 11/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) has been implicated in the transition from a nondependent motivational state to a drug-dependent and -withdrawn motivational state. Chronic nicotine can increase BDNF in the rodent brain and is associated with smoking severity in humans; however, it is unknown whether this increased BDNF is linked functionally to the switch from a nicotine-nondependent to a nicotine-dependent state. We used a place conditioning paradigm to measure the conditioned responses to nicotine, showing that a dose of acute nicotine that nondependent male mice find aversive is found rewarding in chronic nicotine-treated mice experiencing withdrawal. A single BDNF injection in the ventral tegmental area (in the absence of chronic nicotine treatment) caused mice to behave as if they were nicotine-dependent and in withdrawal, switching the neurobiological substrate mediating the conditioned motivational effects from dopamine D1 receptors to D2 receptors. Quantification of gene expression of BDNF and its receptor, tropomyosin-receptor-kinase B (TrkB), revealed an increase in TrkB mRNA but not BDNF mRNA in the VTA in nicotine-dependent and -withdrawn mice. These results suggest that BDNF signaling in the VTA is a critical neurobiological substrate for the transition to nicotine dependence. The modulation of BDNF signaling may be a promising new pharmacological avenue for the treatment of addictive behavior.
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Affiliation(s)
- Taryn E Grieder
- Department of Molecular Genetics and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Mandy Yee
- Department of Molecular Genetics and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Hector Vargas-Perez
- The Nierika Intercultural Medicine Institute, Ocuilan, Estado de México, México
| | - Geith Maal-Bared
- Department of Molecular Genetics and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Susan George
- Department of Molecular Genetics and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Ryan Ting-A-Kee
- Department of Molecular Genetics and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Olivier George
- Department of Psychiatry, UCSD School of Medicine, La Jolla, California, USA
| | - Derek van der Kooy
- Department of Molecular Genetics and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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Single-Dose P2 X4R Single-Chain Fragment Variable Antibody Permanently Reverses Chronic Pain in Male Mice. Int J Mol Sci 2021; 22:ijms222413612. [PMID: 34948407 PMCID: PMC8706307 DOI: 10.3390/ijms222413612] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/02/2021] [Accepted: 12/16/2021] [Indexed: 11/22/2022] Open
Abstract
Non-opioid single-chain variable fragment (scFv) small antibodies were generated as pain-reducing block of P2X4R receptor (P2X4R). A panel of scFvs targeting an extracellular peptide sequence of P2X4R was generated followed by cell-free ribosome display for recombinant antibody selection. After three rounds of bio-panning, a panel of recombinant antibodies was isolated and characterized by ELISA, cross-reactivity analysis, and immunoblotting/immunostaining. Generated scFv antibodies feature binding activity similar to monoclonal antibodies but with stronger affinity and increased tissue penetrability due to their ~30% smaller size. Two anti-P2X4R scFv clones (95, 12) with high specificity and affinity binding were selected for in vivo testing in male and female mice with trigeminal nerve chronic neuropathic pain (FRICT-ION model) persisting for several months in untreated BALBc mice. A single dose of P2X4R scFv (4 mg/kg, i.p.) successfully, completely, and permanently reversed chronic neuropathic pain-like measures in male mice only, providing retention of baseline behaviors indefinitely. Untreated mice retained hypersensitivity, and developed anxiety- and depression-like behaviors within 5 weeks. In vitro P2X4R scFv 95 treatment significantly increased the rheobase of larger-diameter (>25 µm) trigeminal ganglia (TG) neurons from FRICT-ION mice compared to controls. The data support use of engineered scFv antibodies as non-opioid biotherapeutic interventions for chronic pain.
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Abd-El-Basset EM, Rao MS, Alshawaf SM, Ashkanani HK, Kabli AH. Tumor necrosis factor (TNF) induces astrogliosis, microgliosis and promotes survival of cortical neurons. AIMS Neurosci 2021; 8:558-584. [PMID: 34877406 PMCID: PMC8611192 DOI: 10.3934/neuroscience.2021031] [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: 07/18/2021] [Accepted: 11/02/2021] [Indexed: 11/21/2022] Open
Abstract
Objectives Neuro-inflammation occurs as a sequence of brain injury and is associated with production of cytokines. Cytokines can modulate the function and survival of neurons, microglia and astrocytes. The objective of this study is to examine the effect of TNF on the neurons, microglia and astrocytes in normal brain and stab wound brain injury. Methods Normal BALB/c male mice (N) without any injury were subdivided into NA and NB groups. Another set mouse was subjected to stab wound brain injury (I) and were subdivided into IA and IB. NA and IA groups received intraperitoneal injections of TNF (1 µg/kg body weight/day) for nine days, whereas NB and IB groups received intraperitoneal injections of PBS. Animals were killed on 1st, 2nd, 3rd, 7th, and 9th day. Frozen brain sections through the injury site in IA and IB or corresponding region in NA and NB groups were stained for neurodegeneration, immunostained for astrocytes, microglia and neurons. Western blotting for GFAP and ELISA for BDNF were done from the tissues collected from all groups. Results The number of degenerating neurons significantly decreased in TNF treated groups. There was a significant increase in the number of astrocytes and microglia in TNF treated groups compared to PBS treated groups. In addition, it was found that TNF stimulated the expression of GFAP and BDNF in NA and IA groups. Conclusions TNF induces astrogliosis and microgliosis in normal and injured brain and promotes the survival of cortical neurons in stab wound brain injury, may be by upregulating the BDNF level.
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Affiliation(s)
- Ebtesam M Abd-El-Basset
- Department of Anatomy, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13100, Kuwait
| | - Muddanna Sakkattu Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13100, Kuwait
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