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Abarca-Merlin DM, Martínez-Durán JA, Medina-Pérez JD, Rodríguez-Santos G, Alvarez-Arellano L. From Immunity to Neurogenesis: Toll-like Receptors as Versatile Regulators in the Nervous System. Int J Mol Sci 2024; 25:5711. [PMID: 38891900 PMCID: PMC11171594 DOI: 10.3390/ijms25115711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/10/2024] [Accepted: 05/11/2024] [Indexed: 06/21/2024] Open
Abstract
Toll-like receptors (TLRs) are among the main components of the innate immune system. They can detect conserved structures in microorganisms and molecules associated with stress and cellular damage. TLRs are expressed in resident immune cells and both neurons and glial cells of the nervous system. Increasing evidence is emerging on the participation of TLRs not only in the immune response but also in processes of the nervous system, such as neurogenesis and cognition. Below, we present a review of the literature that evaluates the expression and role of TLRs in processes such as neurodevelopment, behavior, cognition, infection, neuroinflammation, and neurodegeneration.
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Affiliation(s)
- Daniela Melissa Abarca-Merlin
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - J. Abigail Martínez-Durán
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - J. David Medina-Pérez
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - Guadalupe Rodríguez-Santos
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - Lourdes Alvarez-Arellano
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
- CONAHCYT-Hospital Infantil de México Federico Gómez, Mexico City 06720, Mexico
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Chen Y, Chen Z, Zhu Y, Wen Y, Zhao C, Mu W. Recent Progress in Human Milk Oligosaccharides and Its Antiviral Efficacy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:7607-7617. [PMID: 38563422 DOI: 10.1021/acs.jafc.3c09460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Gastrointestinal (GI)-associated viruses, including rotavirus (RV), norovirus (NV), and enterovirus, usually invade host cells, transmit, and mutate their genetic information, resulting in influenza-like symptoms, acute gastroenteritis, encephalitis, or even death. The unique structures of human milk oligosaccharides (HMOs) enable them to shape the gut microbial diversity and endogenous immune system of human infants. Growing evidence suggests that HMOs can enhance host resistance to GI-associated viruses but without a systematic summary to review the mechanism. The present review examines the lactose- and neutral-core HMOs and their antiviral effects in the host. The potential negative impacts of enterovirus 71 (EV-A71) and other GI viruses on children are extensive and include neurological sequelae, neurodevelopmental retardation, and cognitive decline. However, the differences in the binding affinity of HMOs for GI viruses are vast. Hence, elucidating the mechanisms and positive effects of HMOs against different viruses may facilitate the development of novel HMO derived oligosaccharides.
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Affiliation(s)
- Yihan Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China
| | - Zhengxin Chen
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China
| | - Yuxi Wen
- College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Department of Analytical and Food Chemistry, Faculty of Sciences, Universidade de Vigo, 32004 Ourense Spain
| | - Chao Zhao
- College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China
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Deng L, Gao R, Chen H, Jiao B, Zhang C, Wei L, Yan C, Ye-Lehmann S, Zhu T, Chen C. Let-7b-TLR7 Signaling Axis Contributes to the Anesthesia/Surgery-Induced Cognitive Impairment. Mol Neurobiol 2024; 61:1818-1832. [PMID: 37782443 DOI: 10.1007/s12035-023-03658-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 09/15/2023] [Indexed: 10/03/2023]
Abstract
Perioperative neurocognitive disorders (PNDs) are severe and common neurological complications among elderly patients following anesthesia and surgery. As the first line of defense of the innate immune system, Toll-like receptors (TLRs) have been found to be involved in the occurrence of neurodegenerative diseases in recent years. However, the role of TLR7 in the pathology and development of PNDs remains largely unclear. In our current study, we hypothesized that increased microRNA let-7b (let-7b) during anesthesia and surgical operation would activate TLR7 signaling pathways and mediate PNDs. Using a mouse model of PNDs, 18-20 months wild-type (WT) mice were undergoing unilateral nephrectomy, and increased TLR7 and let-7b expression levels were found in the surgery group compared with the Sham group. Of note, increased TLR7 was found to be co-localized with let-7b in the hippocampal area CA1 in the PNDs model. In addition, TLR7 and let-7b inhibition could improve hippocampus-dependent memory and attenuate the production of inflammatory cytokines. Together, our results indicated that TLR7 activation and up-regulation might be triggered by increased let-7b under stressful conditions and initiated the downstream inflammatory signaling, playing a substantial role in the development of PNDs.
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Affiliation(s)
- Liyun Deng
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Rui Gao
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Hai Chen
- Department of Respiratory and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, West China Hospital, Sichuan University, Chengdu, China
| | - Bo Jiao
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Changteng Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Liuxing Wei
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Caiyi Yan
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Shixin Ye-Lehmann
- Unité INSERM U1195, Diseases and Hormones of the Nervous System, University of Paris-Scalay, Bicêtre Hosptial, Bât. Grégory Pincus, Le Kremlin-Bicêtre, France
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Chan Chen
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.
- The Research Units of West China (2018RU012)-Chinese Academy of Medical Sciences, West China Hospital, Sichuan University, Chengdu, China.
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Patterson R, Balan I, Morrow AL, Meltzer-Brody S. Novel neurosteroid therapeutics for post-partum depression: perspectives on clinical trials, program development, active research, and future directions. Neuropsychopharmacology 2024; 49:67-72. [PMID: 37715106 PMCID: PMC10700474 DOI: 10.1038/s41386-023-01721-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/18/2023] [Accepted: 08/23/2023] [Indexed: 09/17/2023]
Abstract
This article reviews novel neurosteroid therapeutics for post-partum depression, with a focus on their development, clinical trial data, current practices, and future directions in this exciting field. We discuss the clinical impact of brexanolone and several other neurosteroids, particularly as they relate to the treatment of postpartum depression (PPD) and major depressive disorders outside of the perinatal period. There has been increasing interest in GABA signaling and modulation as it pertains to the development of altered circuity and depressive states. This scientific underpinning served as the rationale for the initial development of brexanolone. We review the clinical trials supporting its Food and Drug Administration (FDA) approval as the first rapidly acting antidepressant specific for PPD, and the subsequent development of a clinical brexanolone program at an academic medical center, highlighting new research and data from that site as well as the challenges with the delivery of this I.V. drug. In addition to the GABA signaling hypothesis, we discuss the new evidence demonstrating that brexanolone inhibits inflammatory signaling post-infusion, suggesting that inflammatory signaling may contribute to the etiology of PPD. Finally, we describe new and future directions in neurosteroid therapeutics, including the development of an oral agent, zuranolone, and the IV and oral formulations of ganaxolone. Ultimately, the hope is that these novel neurosteroid therapeutics will provide fast-acting treatment for these impairing disorders and improve our understanding of the underlying mechanisms of depressive disorders.
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Affiliation(s)
- Riah Patterson
- Department of Psychiatry and Emergency Medicine, MacNider Bldg. Suite 304, CB# 7160, Chapel Hill, NC, 27599-7160, USA.
| | - Irina Balan
- Department of Psychiatry, Bowles Center for Alcohol Studies, 3027 Thurston Bowles Building, CB 7178, Chapel Hill, NC, 27599-7178, USA
| | - A Leslie Morrow
- Department of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, 3027 Thurston Bowles Building, CB 7178, Chapel Hill, NC, 27599-7178, USA
| | - Samantha Meltzer-Brody
- Department of Psychiatry, UNC Center for Women's Mood Disorders, MacNider Bldg. Suite 304CB #7160, Chapel Hill, NC, 27599-7160, USA
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Fang S, Wu Z, Guo Y, Zhu W, Wan C, Yuan N, Chen J, Hao W, Mo X, Guo X, Fan L, Li X, Chen J. Roles of microglia in adult hippocampal neurogenesis in depression and their therapeutics. Front Immunol 2023; 14:1193053. [PMID: 37881439 PMCID: PMC10597707 DOI: 10.3389/fimmu.2023.1193053] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 09/20/2023] [Indexed: 10/27/2023] Open
Abstract
Adult hippocampal neurogenesis generates functional neurons from neural progenitor cells in the hippocampal dentate gyrus (DG) to complement and repair neurons and neural circuits, thus benefiting the treatment of depression. Increasing evidence has shown that aberrant microglial activity can disrupt the appropriate formation and development of functional properties of neurogenesis, which will play a crucial role in the occurrence and development of depression. However, the mechanisms of the crosstalk between microglia and adult hippocampal neurogenesis in depression are not yet fully understood. Therefore, in this review, we first introduce recent discoveries regarding the roles of microglia and adult hippocampal neurogenesis in the etiology of depression. Then, we systematically discuss the possible mechanisms of how microglia regulate adult hippocampal neurogenesis in depression according to recent studies, which involve toll-like receptors, microglial polarization, fractalkine-C-X3-C motif chemokine receptor 1, hypothalamic-pituitary-adrenal axis, cytokines, brain-derived neurotrophic factor, and the microbiota-gut-brain axis, etc. In addition, we summarize the promising drugs that could improve the adult hippocampal neurogenesis by regulating the microglia. These findings will help us understand the complicated pathological mechanisms of depression and shed light on the development of new treatment strategies for this disease.
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Affiliation(s)
- Shaoyi Fang
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Zhibin Wu
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Yali Guo
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Wenjun Zhu
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Chunmiao Wan
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Naijun Yuan
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
- Shenzhen People’s Hospital, 2Clinical Medical College, Jinan University, Shenzhen, China
| | - Jianbei Chen
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Wenzhi Hao
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Xiaowei Mo
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Xiaofang Guo
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Lili Fan
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Xiaojuan Li
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
| | - Jiaxu Chen
- Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, China
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
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Wang W, Kong Y, Wang X, Wang Z, Tang C, Li J, Yang Q, Chen YQ, Zhu S. Identification of novel SCD1 inhibitor alleviates nonalcoholic fatty liver disease: critical role of liver-adipose axis. Cell Commun Signal 2023; 21:268. [PMID: 37777801 PMCID: PMC10544195 DOI: 10.1186/s12964-023-01297-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/25/2023] [Indexed: 10/02/2023] Open
Abstract
Due to the complexity and incomplete understanding of the crosstalk between liver and adipose tissue, especially the processes of hepatic lipogenesis and adipogenic differentiation, there are currently no effective drugs for the treatment of nonalcoholic fatty liver disease (NAFLD). Stearoyl-coenzyme A desaturase 1 (SCD1), which is abundantly expressed in liver and adipose tissue, may mediate the cross-talk between liver and adipose tissue. Thus, it is essential to develop specific SCD1 inhibitors that target the liver-adipose axis. Herein, we identified a novel SCD1 inhibitor, E6446, through a high-throughput virtual screen. E6646 significantly inhibited adipogenic differentiation and hepatic lipogenesis via SCD1-ATF3 signaling. The SPR results showed that E6446 had a strong interaction ability with SCD1 (KD:4.61 μM). Additionally, E6646 significantly decreased hepatic steatosis, hepatic lipid droplet accumulation and insulin resistance in high-fat diet (HFD)-fed mice. Taken together, our findings not only suggest that E6446 can serve as a new, safe and highly effective anti-NAFLD agent for future clinical use but also provide a molecular basis for the future development of SCD1 inhibitors that inhibit both adipogenic differentiation and hepatic lipogenesis. Video Abstract.
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Affiliation(s)
- Wei Wang
- Jiangnan University Medical Center, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Yulin Kong
- Jiangnan University Medical Center, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Xia Wang
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, China
| | - Zhe Wang
- Jiangnan University Medical Center, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Chunlei Tang
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, China
| | - Jinyou Li
- Affiliated Hospital of Jiangnan University, Wuxi, China
| | - Qin Yang
- Jiangnan University Medical Center, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Yong Q Chen
- Jiangnan University Medical Center, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Shenglong Zhu
- Jiangnan University Medical Center, Wuxi School of Medicine, Jiangnan University, Wuxi, China.
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Yen TL, Huang TN, Lin MH, Hsu TT, Lu MH, Shih PY, Ellegood J, Lerch J, Hsueh YP. Sex bias in social deficits, neural circuits and nutrient demand in Cttnbp2 autism models. Brain 2023; 146:2612-2626. [PMID: 36385662 PMCID: PMC10232293 DOI: 10.1093/brain/awac429] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/04/2022] [Accepted: 11/04/2022] [Indexed: 09/02/2023] Open
Abstract
Autism spectrum disorders caused by both genetic and environmental factors are strongly male-biased neuropsychiatric conditions. However, the mechanism underlying the sex bias of autism spectrum disorders remains elusive. Here, we use a mouse model in which the autism-linked gene Cttnbp2 is mutated to explore the potential mechanism underlying the autism sex bias. Autism-like features of Cttnbp2 mutant mice were assessed via behavioural assays. C-FOS staining identified sex-biased brain regions critical to social interaction, with their roles and connectivity then validated by chemogenetic manipulation. Proteomic and bioinformatic analyses established sex-biased molecular deficits at synapses, prompting our hypothesis that male-biased nutrient demand magnifies Cttnbp2 deficiency. Accordingly, intakes of branched-chain amino acids (BCAA) and zinc were experimentally altered to assess their effect on autism-like behaviours. Both deletion and autism-linked mutation of Cttnbp2 result in male-biased social deficits. Seven brain regions, including the infralimbic area of the medial prefrontal cortex (ILA), exhibit reduced neural activity in male mutant mice but not in females upon social stimulation. ILA activation by chemogenetic manipulation is sufficient to activate four of those brain regions susceptible to Cttnbp2 deficiency and consequently to ameliorate social deficits in male mice, implying an ILA-regulated neural circuit is critical to male-biased social deficits. Proteomics analysis reveals male-specific downregulated proteins (including SHANK2 and PSD-95, two synaptic zinc-binding proteins) and female-specific upregulated proteins (including RRAGC) linked to neuropsychiatric disorders, which are likely relevant to male-biased deficits and a female protective effect observed in Cttnbp2 mutant mice. Notably, RRAGC is an upstream regulator of mTOR that senses BCAA, suggesting that mTOR exerts a beneficial effect on females. Indeed, increased BCAA intake activates the mTOR pathway and rescues neuronal responses and social behaviours of male Cttnbp2 mutant mice. Moreover, mutant males exhibit greatly increased zinc demand to display normal social behaviours. Mice carrying an autism-linked Cttnbp2 mutation exhibit male-biased social deficits linked to specific brain regions, differential synaptic proteomes and higher demand for BCAA and zinc. We postulate that lower demand for zinc and BCAA are relevant to the female protective effect. Our study reveals a mechanism underlying sex-biased social defects and also suggests a potential therapeutic approach for autism spectrum disorders.
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Affiliation(s)
- Tzu-Li Yen
- Molecular and Cell Biology, Taiwan International Graduate Program, Institute of Molecular Biology, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11529, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Tzyy-Nan Huang
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Ming-Hui Lin
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Tsan-Ting Hsu
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Ming-Hsuan Lu
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Pu-Yun Shih
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Jacob Ellegood
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario M5T 3H7, Canada
- Department of Medical Biophysics, The University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Jason Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario M5T 3H7, Canada
- Department of Medical Biophysics, The University of Toronto, Toronto, Ontario M5G 1L7, Canada
- Wellcome Centre for Integrative Neuroimaging, The University of Oxford, Oxford OX3 9DU, UK
| | - Yi-Ping Hsueh
- Molecular and Cell Biology, Taiwan International Graduate Program, Institute of Molecular Biology, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11529, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
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Liu J, Ke P, Guo H, Gu J, Liu Y, Tian X, Wang X, Xiao F. Activation of TLR7-mediated autophagy increases epileptic susceptibility via reduced KIF5A-dependent GABA A receptor transport in a murine model. Exp Mol Med 2023; 55:1159-1173. [PMID: 37258573 PMCID: PMC10317981 DOI: 10.1038/s12276-023-01000-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 06/02/2023] Open
Abstract
The pathophysiological mechanisms underlying epileptogenesis are poorly understood but are considered to actively involve an imbalance between excitatory and inhibitory synaptic transmission. Excessive activation of autophagy, a cellular pathway that leads to the removal of proteins, is known to aggravate the disease. Toll-like receptor (TLR) 7 is an innate immune receptor that regulates autophagy in infectious and noninfectious diseases. However, the relationship between TLR7, autophagy, and synaptic transmission during epileptogenesis remains unclear. We found that TLR7 was activated in neurons in the early stage of epileptogenesis. TLR7 knockout significantly suppressed seizure susceptibility and neuronal excitability. Furthermore, activation of TLR7 induced autophagy and decreased the expression of kinesin family member 5 A (KIF5A), which influenced interactions with γ-aminobutyric acid type A receptor (GABAAR)-associated protein and GABAARβ2/3, thus producing abnormal GABAAR-mediated postsynaptic transmission. Our results indicated that TLR7 is an important factor in regulating epileptogenesis, suggesting a possible therapeutic target for epilepsy.
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Affiliation(s)
- Jing Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China
- Department of Neurology, Chongqing University Three Gorges Hospital, 165 Xincheng Road, Chongqing, 404100, China
| | - Pingyang Ke
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China
| | - Haokun Guo
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China
| | - Juan Gu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China
| | - Yan Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China
| | - Xin Tian
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China.
| | - Fei Xiao
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing, 400016, China.
- Institute for Brain Science and Disease of Chongqing Medical University, Chongqing, 400016, China.
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Su W, Ju J, Gu M, Wang X, Liu S, Yu J, Mu D. SARS-CoV-2 envelope protein triggers depression-like behaviors and dysosmia via TLR2-mediated neuroinflammation in mice. J Neuroinflammation 2023; 20:110. [PMID: 37158916 PMCID: PMC10166055 DOI: 10.1186/s12974-023-02786-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/20/2023] [Indexed: 05/10/2023] Open
Abstract
BACKGROUND Depression and dysosmia have been regarded as primary neurological symptoms in COVID-19 patients, the mechanism of which remains unclear. Current studies have demonstrated that the SARS-CoV-2 envelope (E) protein is a pro-inflammatory factor sensed by Toll-like receptor 2 (TLR2), suggesting the pathological feature of E protein is independent of viral infection. In this study, we aim to ascertain the role of E protein in depression, dysosmia and associated neuroinflammation in the central nervous system (CNS). METHODS Depression-like behaviors and olfactory function were observed in both female and male mice receiving intracisternal injection of E protein. Immunohistochemistry was applied in conjunction with RT-PCR to evaluate glial activation, blood-brain barrier status and mediators synthesis in the cortex, hippocampus and olfactory bulb. TLR2 was pharmacologically blocked to determine its role in E protein-related depression-like behaviors and dysosmia in mice. RESULTS Intracisternal injection of E protein evoked depression-like behaviors and dysosmia in both female and male mice. Immunohistochemistry suggested that the E protein upregulated IBA1 and GFAP in the cortex, hippocampus and olfactory bulb, while ZO-1 was downregulated. Moreover, IL-1β, TNF-α, IL-6, CCL2, MMP2 and CSF1 were upregulated in both cortex and hippocampus, whereas IL-1β, IL-6 and CCL2 were upregulated in the olfactory bulb. Furtherly, inhibiting microglia, rather than astrocytes, alleviated depression-like behaviors and dysosmia induced by E protein. Finally, RT-PCR and immunohistochemistry suggested that TLR2 was upregulated in the cortex, hippocampus and olfactory bulb, the blocking of which mitigated depression-like behaviors and dysosmia induced by E protein. CONCLUSIONS Our study demonstrates that envelope protein could directly induce depression-like behaviors, dysosmia, and obvious neuroinflammation in CNS. TLR2 mediated depression-like behaviors and dysosmia induced by envelope protein, which could serve as a promising therapeutic target for neurological manifestation in COVID-19 patients.
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Affiliation(s)
- Wenliang Su
- Department of Anesthesiology, Peking University First Hospital, Beijing, China
| | - Jiahang Ju
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-Machine Integration, State Key Laboratory of Brain-Machine Intelligence, Zhejiang University, Hangzhou, 311121 China
| | - Minghui Gu
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei China
| | - Xinrui Wang
- Department of Pharmacy, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Shaozhuang Liu
- Department of Urology, Shengjing Hospital of China Medical University, Sanhao Street 36, Shenyang, 110004 Liaoning China
| | - Jiawen Yu
- Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dongliang Mu
- Department of Anesthesiology, Peking University First Hospital, Beijing, China
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10
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Lovelock DF, Liu W, Langston SE, Liu J, Van Voorhies K, Giffin KA, Vetreno RP, Crews FT, Besheer J. The Toll-like receptor 7 agonist imiquimod increases ethanol self-administration and induces expression of Toll-like receptor related genes. Addict Biol 2022; 27:e13176. [PMID: 35470561 PMCID: PMC9286850 DOI: 10.1111/adb.13176] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/24/2022] [Accepted: 04/08/2022] [Indexed: 12/24/2022]
Abstract
There is growing evidence that immune signalling may be involved in both the causes and consequences of alcohol abuse. Toll-like receptor (TLR) expression is increased by alcohol consumption and is implicated in AUD, and specifically TLR7 may play an important role in ethanol consumption. We administered the TLR7-specific agonist imiquimod in male and female Long-Evans rats to determine (1) gene expression changes in brain regions involved in alcohol reinforcement, the nucleus accumbens core and anterior insular cortex, in rats with and without an alcohol history, and (2) whether TLR7 activation could modulate operant alcohol self-administration. Interferon regulatory factor 7 (IRF7) was dramatically increased in both sexes at both 2- and 24-h post-injection regardless of alcohol history and TLR3 and 7 gene expression was increased as well. The proinflammatory cytokine TNFα was increased 24-h post-injection in rats with an alcohol self-administration history, but this effect did not persist after four injections, suggesting molecular tolerance. Ethanol consumption was increased 24 h after imiquimod injections but did not occur until the third injection, suggesting adaptation to repeated TLR7 activation is necessary for increased drinking to occur. Notably, imiquimod reliably induced weight loss, indicating that sickness behaviour persisted across repeated injections. These findings show that TLR7 activation can modulate alcohol drinking in an operant self-administration paradigm and suggest that TLR7 and IRF7 signalling pathways may be a viable druggable target for treatment of AUD.
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Affiliation(s)
- Dennis F. Lovelock
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Wen Liu
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Sarah E. Langston
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Jiaqi Liu
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Kalynn Van Voorhies
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Kaitlin A. Giffin
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Ryan P. Vetreno
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
- Department of Psychiatry University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Fulton T. Crews
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
- Department of Psychiatry University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
- Department of Pharmacology University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
| | - Joyce Besheer
- Bowles Center for Alcohol Studies University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
- Department of Psychiatry University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
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11
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Acioglu C, Heary RF, Elkabes S. Roles of neuronal toll-like receptors in neuropathic pain and central nervous system injuries and diseases. Brain Behav Immun 2022; 102:163-178. [PMID: 35176442 DOI: 10.1016/j.bbi.2022.02.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/12/2022] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
Toll-like receptors (TLRs) are innate immune receptors that are expressed in immune cells as well as glia and neurons of the central and peripheral nervous systems. They are best known for their role in the host defense in response to pathogens and for the induction of inflammation in infectious and non-infectious diseases. In the central nervous system (CNS), TLRs modulate glial and neuronal functions as well as innate immunity and neuroinflammation under physiological or pathophysiological conditions. The majority of the studies on TLRs in CNS pathologies investigated their overall contribution without focusing on a particular cell type, or they analyzed TLRs in glia and infiltrating immune cells in the context of neuroinflammation and cellular activation. The role of neuronal TLRs in CNS diseases and injuries has received little attention and remains underappreciated. The primary goal of this review is to summarize findings demonstrating the pivotal and unique roles of neuronal TLRs in neuropathic pain, Alzheimer's disease, Parkinson's disease and CNS injuries. We discuss how the current findings warrant future investigations to better define the specific contributions of neuronal TLRs to these pathologies. We underline the paucity of information regarding the role of neuronal TLRs in other neurodegenerative, demyelinating, and psychiatric diseases. We draw attention to the importance of broadening research on neuronal TLRs in view of emerging evidence demonstrating their distinctive functional properties.
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Affiliation(s)
- Cigdem Acioglu
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Robert F Heary
- Department of Neurological Surgery, Hackensack Meridian School of Medicine, Mountainside Medical Center, Montclair, NJ 07042, United States
| | - Stella Elkabes
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
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12
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Zengeler KE, Lukens JR. Innate immunity at the crossroads of healthy brain maturation and neurodevelopmental disorders. Nat Rev Immunol 2021; 21:454-468. [PMID: 33479477 PMCID: PMC9213174 DOI: 10.1038/s41577-020-00487-7] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2020] [Indexed: 12/29/2022]
Abstract
The immune and nervous systems have unique developmental trajectories that individually build intricate networks of cells with highly specialized functions. These two systems have extensive mechanistic overlap and frequently coordinate to accomplish the proper growth and maturation of an organism. Brain resident innate immune cells - microglia - have the capacity to sculpt neural circuitry and coordinate copious and diverse neurodevelopmental processes. Moreover, many immune cells and immune-related signalling molecules are found in the developing nervous system and contribute to healthy neurodevelopment. In particular, many components of the innate immune system, including Toll-like receptors, cytokines, inflammasomes and phagocytic signals, are critical contributors to healthy brain development. Accordingly, dysfunction in innate immune signalling pathways has been functionally linked to many neurodevelopmental disorders, including autism and schizophrenia. This review discusses the essential roles of microglia and innate immune signalling in the assembly and maintenance of a properly functioning nervous system.
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Affiliation(s)
- Kristine E Zengeler
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), Charlottesville, VA, USA.
- Neuroscience Graduate Program, Charlottesville, VA, USA.
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA, USA.
| | - John R Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), Charlottesville, VA, USA.
- Neuroscience Graduate Program, Charlottesville, VA, USA.
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA, USA.
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13
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Chen CY, Hung YF, Tsai CY, Shih YC, Chou TF, Lai MZ, Wang TF, Hsueh YP. Transcriptomic Analysis and C-Terminal Epitope Tagging Reveal Differential Processing and Signaling of Endogenous TLR3 and TLR7. Front Immunol 2021; 12:686060. [PMID: 34211474 PMCID: PMC8240634 DOI: 10.3389/fimmu.2021.686060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/01/2021] [Indexed: 01/02/2023] Open
Abstract
Toll-like receptor (TLR) signaling is critical for defense against pathogenic infection, as well as for modulating tissue development. Activation of different TLRs triggers common inflammatory responses such as cytokine induction. Here, we reveal differential impacts of TLR3 and TLR7 signaling on transcriptomic profiles in bone marrow-derived macrophages (BMDMs). Apart from self-regulation, TLR3, but not TLR7, induced expression of other TLRs, suggesting that TLR3 activation globally enhances innate immunity. Moreover, we observed diverse influences of TLR3 and TLR7 signaling on genes involved in methylation, caspase and autophagy pathways. We compared endogenous TLR3 and TLR7 by using CRISPR/Cas9 technology to knock in a dual Myc-HA tag at the 3’ ends of mouse Tlr3 and Tlr7. Using anti-HA antibodies to detect endogenous tagged TLR3 and TLR7, we found that both TLRs display differential tissue expression and posttranslational modifications. C-terminal tagging did not impair TLR3 activity. However, it disrupted the interaction between TLR7 and myeloid differentiation primary response 88 (MYD88), the Tir domain-containing adaptor of TLR7, which blocked its downstream signaling necessary to trigger cytokine and chemokine expression. Our study demonstrates different properties for TLR3 and TLR7, and also provides useful mouse models for further investigation of these two RNA-sensing TLRs.
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Affiliation(s)
- Chiung-Ya Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yun-Fen Hung
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ching-Yen Tsai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Chun Shih
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ting-Fang Chou
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ming-Zong Lai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ting-Fang Wang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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14
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Lyons-Warren AM, Herman I, Hunt PJ, Arenkiel BR. A systematic-review of olfactory deficits in neurodevelopmental disorders: From mouse to human. Neurosci Biobehav Rev 2021; 125:110-121. [PMID: 33610612 PMCID: PMC8142839 DOI: 10.1016/j.neubiorev.2021.02.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 01/15/2021] [Accepted: 02/15/2021] [Indexed: 01/07/2023]
Abstract
Olfactory impairment is a common clinical motif across neurodevelopmental disorders, suggesting olfactory circuits are particularly vulnerable to disease processes and can provide insight into underlying disease mechanisms. The mouse olfactory bulb is an ideal model system to study mechanisms of neurodevelopmental disease due to its anatomical accessibility, behavioral relevance, ease of measuring circuit input and output, and the feature of adult neurogenesis. Despite the clinical relevance and experimental benefits, olfactory testing across animal models of neurodevelopmental disease has been inconsistent and non-standardized. Here we performed a systematic literature review of olfactory function testing in mouse models of neurodevelopmental disorders, and identified intriguing inconsistencies that include evidence for both increased and decreased acuity in odor detection in various mouse models of Autism Spectrum Disorder (ASD). Based on our identified gaps in the literature, we recommend direct comparison of different mouse models of ASD using standardized tests for odor detection and discrimination. This review provides a framework to guide future olfactory function testing in mouse models of neurodevelopmental diseases.
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Affiliation(s)
- Ariel M Lyons-Warren
- Baylor College of Medicine, Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience; Clinical Care Center, Suite 1250, 6621 Fannin St, Houston, TX 77030, United States of America;,Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030 USA
| | - Isabella Herman
- Baylor College of Medicine, Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience; Clinical Care Center, Suite 1250, 6621 Fannin St, Houston, TX 77030, United States of America;,Baylor College of Medicine, Department of Molecular & Human Genetics; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America
| | - Patrick J Hunt
- Baylor College of Medicine, Department of Molecular & Human Genetics; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America
| | - Benjamin R Arenkiel
- Baylor College of Medicine, Department of Molecular & Human Genetics; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America;,Baylor College of Medicine, Department of Neuroscience; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America;,Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030 USA.,McNair Medical Institute, Baylor College of Medicine, Houston, TX 77030
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15
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Hung YF, Hsueh YP. TLR7 and IL-6 differentially regulate the effects of rotarod exercise on the transcriptomic profile and neurogenesis to influence anxiety and memory. iScience 2021; 24:102384. [PMID: 33981972 PMCID: PMC8082089 DOI: 10.1016/j.isci.2021.102384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/20/2021] [Accepted: 03/30/2021] [Indexed: 11/06/2022] Open
Abstract
Voluntary exercise is well known to benefit brain performance. In contrast, forced exercise induces inflammation-related stress responses and may cause psychiatric disorders. Here, we unexpectedly found that rotarod testing, a frequently applied assay for evaluating rodent motor coordination, induces anxiety and alters spatial learning/memory performance of mice. Rotarod testing upregulated genes involved in the unfolded protein response and stress responses and downregulated genes associated with neurogenesis and neuronal differentiation. It impacts two downstream pathways. The first is the IL-6-dependent pathway, which mediates rotarod-induced anxiety. The second is the Toll-like receptor 7 (TLR7)-dependent pathway, which is involved in the effect of rotarod exercise on gene expression and its impact on contextual learning and memory of mice. Thus, although rotarod exercise does not induce systemic inflammation, it influences innate immunity-related responses in the brain, controls gene expression and, consequently, regulates anxiety and contextual learning and memory. Rotarod training at 5 or 10 weeks of age induces anxious behavior in an open field Rotarod training upregulates IL-6 expression in the brain and results in anxiety Rotarod training alters performances of test mice in spatial learning and memory TLR7 controls the rotarod-impacted transcriptomic profiles and contextual memory
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Affiliation(s)
- Yun-Fen Hung
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
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16
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Balan I, Aurelian L, Schleicher R, Boero G, O'Buckley T, Morrow AL. Neurosteroid allopregnanolone (3α,5α-THP) inhibits inflammatory signals induced by activated MyD88-dependent toll-like receptors. Transl Psychiatry 2021; 11:145. [PMID: 33637705 PMCID: PMC7909379 DOI: 10.1038/s41398-021-01266-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 02/08/2023] Open
Abstract
We have shown that endogenous neurosteroids, including pregnenolone and 3α,5α-THP inhibit toll-like receptor 4 (TLR4) signal activation in mouse macrophages and the brain of alcohol-preferring (P) rat, which exhibits innate TLR4 signal activation. The current studies were designed to examine whether other activated TLR signals are similarly inhibited by 3α,5α-THP. We report that 3α,5α-THP inhibits selective agonist-mediated activation of TLR2 and TLR7, but not TLR3 signaling in the RAW246.7 macrophage cell line. The TLR4 and TLR7 signals are innately activated in the amygdala and NAc from P rat brains and inhibited by 3α,5α-THP. The TLR2 and TLR3 signals are not activated in P rat brain and they are not affected by 3α,5α-THP. Co-immunoprecipitation studies indicate that 3α,5α-THP inhibits the binding of MyD88 with TLR4 or TLR7 in P rat brain, but the levels of TLR4 co-precipitating with TRIF are not altered by 3α,5α-THP treatment. Collectively, the data indicate that 3α,5α-THP inhibits MyD88- but not TRIF-dependent TLR signal activation and the production of pro-inflammatory mediators through its ability to block TLR-MyD88 binding. These results have applicability to many conditions involving pro-inflammatory TLR activation of cytokines, chemokines, and interferons and support the use of 3α,5α-THP as a therapeutic for inflammatory disease.
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Affiliation(s)
- Irina Balan
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - Laure Aurelian
- Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Riana Schleicher
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - Giorgia Boero
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - Todd O'Buckley
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA
| | - A Leslie Morrow
- Department of Psychiatry, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA.
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17
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Abstract
Fetal neurodevelopment in utero is profoundly shaped by both systemic maternal immunity and local processes at the maternal-fetal interface. Immune pathways are a critical participant in the normal physiology of pregnancy and perturbations of maternal immunity due to infections during this period have been increasingly linked to a diverse array of poor neurological outcomes, including diseases that manifest much later in postnatal life. While experimental models of maternal immune activation (MIA) have provided groundbreaking characterizations of the maternal pathways underlying pathogenesis, less commonly examined are the immune factors that serve pathogen-independent developmental functions in the embryo and fetus. In this review, we explore what is known about the in vivo role of immune factors in fetal neurodevelopment during normal pregnancy and provide an overview of how MIA perturbs the proper orchestration of this sequence of events. Finally, we discuss how the dysregulation of immune factors may contribute to the manifestation of a variety of neurological disorders.
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Affiliation(s)
- Alice Lu-Culligan
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut 06519, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut 06519, USA.,Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06519, USA; .,Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06519, USA
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18
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Arnaboldi F, Sommariva M, Opizzi E, Rasile M, Camelliti S, Busnelli M, Menegola E, Di Renzo F, Menon A, Barajon I. Expression of Toll-like receptors 4 and 7 in murine peripheral nervous system development. Ann Anat 2020; 231:151526. [PMID: 32380196 DOI: 10.1016/j.aanat.2020.151526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 02/03/2020] [Accepted: 04/10/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND Toll-Like Receptors (TLRs) play a critical role in the innate and adaptive immune system. They are the mammalian orthologs of Drosophila melanogaster protein Toll, which has been proved to have an early morphogenetic role in invertebrate embryogenesis that in the adult switches to an immune function. AIM The aim of this study was to evaluate the expression of TLR4 and TLR7 during dorsal root ganglia (DRG), paravertebral ganglia (PVG), and enteric nervous system (ENS) murine development. METHODS Mouse embryos from different stages (i.e. E12 to E18) were processed for immunolocalization analysis on formalin-fixed paraffin-embedded sections, and isolated intestine were processed for whole-mount preparations. RESULTS We observed a differentially regulated expression of TLR4 and TLR7 during embryogenesis and an overall increased expression of both receptors during development. While TLR4 was detectable in neurons of DRG and PVG starting from E14 and only from E18 in the ENS, TLR7 was already expressed in scattered neurons of all the investigated regions at E12. CONCLUSIONS TLR4 and TRL7 expression temporal patterns suggest a morphogenetic role for these receptors in the development of neural crest derivatives in mammals.
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Affiliation(s)
- Francesca Arnaboldi
- Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy.
| | - Michele Sommariva
- Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy
| | - Emanuela Opizzi
- Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy
| | - Marco Rasile
- Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano, Milano, Italy; Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milano, Italy
| | - Simone Camelliti
- Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy
| | - Marco Busnelli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Via Balzaretti, 9/11/13, 20133 Milano, Italy
| | - Elena Menegola
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Francesca Di Renzo
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Alessandra Menon
- Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy; Clinica Ortopedica, ASST Centro Specialistico Ortopedico Traumatologico Gaetano Pini-CTO, Milan, Italy
| | - Isabella Barajon
- Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milano, Italy
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19
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Cho KHT, Zeng N, Anekal PV, Xu B, Fraser M. Effects of delayed intraventricular TLR7 agonist administration on long-term neurological outcome following asphyxia in the preterm fetal sheep. Sci Rep 2020; 10:6904. [PMID: 32327682 PMCID: PMC7181613 DOI: 10.1038/s41598-020-63770-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/31/2020] [Indexed: 02/07/2023] Open
Abstract
In the preterm brain, accumulating evidence suggests toll-like receptors (TLRs) are key mediators of the downstream inflammatory pathways triggered by hypoxia-ischemia (HI), which have the potential to exacerbate or ameliorate injury. Recently we demonstrated that central acute administration of the TLR7 agonist Gardiquimod (GDQ) confers neuroprotection in the preterm fetal sheep at 3 days post-asphyxial recovery. However, it is unknown whether GDQ can afford long-term protection. To address this, we examined the long-term effects of GDQ. Briefly, fetal sheep (0.7 gestation) received sham asphyxia or asphyxia induced by umbilical cord occlusion, and were studied for 7 days recovery. Intracerebroventricular (ICV) infusion of GDQ (total dose 3.34 mg) or vehicle was performed from 1-4 hours after asphyxia. GDQ was associated with a robust increase in concentration of tumor necrosis factor-(TNF)-α in the fetal plasma, and interleukin-(IL)-10 in both the fetal plasma and cerebrospinal fluid. GDQ did not significantly change the number of total and immature/mature oligodendrocytes within the periventricular and intragyral white matter. No changes were observed in astroglial and microglial numbers and proliferating cells in both white matter regions. GDQ increased neuronal survival in the CA4 region of the hippocampus, but was associated with exacerbated neuronal injury within the caudate nucleus. In conclusion, our data suggest delayed acute ICV administration of GDQ after severe HI in the developing brain may not support long-term neuroprotection.
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Affiliation(s)
- Kenta H T Cho
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Nina Zeng
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Praju V Anekal
- Biomedical Imaging Research Unit, The University of Auckland, Auckland, New Zealand
| | - Bing Xu
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- The Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, 518000, People's Republic of China
| | - Mhoyra Fraser
- Department of Physiology, The University of Auckland, Auckland, New Zealand.
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20
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Hsu TT, Huang TN, Hsueh YP. Anterior Commissure Regulates Neuronal Activity of Amygdalae and Influences Locomotor Activity, Social Interaction and Fear Memory in Mice. Front Mol Neurosci 2020; 13:47. [PMID: 32296306 PMCID: PMC7136557 DOI: 10.3389/fnmol.2020.00047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/06/2020] [Indexed: 12/21/2022] Open
Abstract
The two hemispheres of the vertebrate brain are connected through several commissures. Although the anterior commissure (AC) is the most conserved white matter structure in the brains of different vertebrates, its complete physiological functionality remains elusive. Since the AC is involved in the connection between two amygdalae and because amygdalae are critical for emotional behaviors and social interaction, we assessed amygdalar activity and function to investigate the physiological role of the AC. We first performed ex vivo electrophysiological recording on mouse brains to demonstrate that the AC delivers a positive signal to facilitate synaptic responses and to recruit basolateral amygdalar neurons via glutamatergic synapses. Transection was then undertaken to investigate the role of the AC in vivo. Results from in vivo optogenetic stimulation suggest that AC transection impairs mutual activation between two basolateral amygdalae. Behavioral analyses were then used to assess if AC surgical lesioning results in hyperactivity, anxiety, social reduction or learning/memory impairment, which are behavioral features associated with neuropsychiatric disorders, such as autism spectrum disorders. We found that AC transection results in higher locomotor activity, aberrant social interaction and reduced associative memory, but not anxiety. Moreover, systemic administration of D-cycloserine, a coagonist of N-methyl-D-aspartate receptor, ameliorated auditory fear memory in AC-transected mice, reinforcing our evidence that the AC potentiates the activity of basolateral amygdalae. Our study suggests that the AC regulates basolateral amygdalar activity and influences neuropsychiatry-related behaviors in mice.
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Affiliation(s)
- Tsan-Ting Hsu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Tzyy-Nan Huang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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21
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Luo Z, Su R, Wang W, Liang Y, Zeng X, Shereen MA, Bashir N, Zhang Q, Zhao L, Wu K, Liu Y, Wu J. EV71 infection induces neurodegeneration via activating TLR7 signaling and IL-6 production. PLoS Pathog 2019; 15:e1008142. [PMID: 31730654 PMCID: PMC6932824 DOI: 10.1371/journal.ppat.1008142] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 12/26/2019] [Accepted: 10/09/2019] [Indexed: 01/13/2023] Open
Abstract
As a neurotropic virus, human Enterovirus 71 (EV71) infection causes hand-foot-and-mouth disease (HFMD) and may develop severe neurological disorders in infants. Toll-like receptor 7 (TLR7) acts as an innate immune receptor and is also a death receptor in the central nervous system (CNS). However, the mechanisms underlying the regulation of TLR7-mediated brain pathogenesis upon EV71 infection remain largely elusive. Here we reveal a novel mechanism by which EV71 infects astrocytes in the brain and induces neural pathogenesis via TLR7 and interleukin-6 (IL-6) in C57BL/6 mice and in human astroglioma U251 cells. Upon EV71 infection, wild-type (WT) mice displayed more significant body weight loss, higher clinical scores, and lower survival rates as compared with TLR7-/- mice. In the cerebral cortex of EV71-infected mice, neurofilament integrity was disrupted, and inflammatory cell infiltration and neurodegeneration were induced in WT mice, whereas these were largely absent in TLR7-/- mice. Similarly, IL-6 production, Caspase-3 cleavage, and cell apoptosis were significantly higher in EV71-infected WT mice as compared with TLR7-/- mice. Moreover, EV71 preferentially infected and induced IL-6 in astrocytes of mice brain. In U251 cells, EV71-induced IL-6 production and cell apoptosis were suppressed by shRNA-mediated knockdown of TLR7 (shTLR7). Moreover, in the cerebral cortex of EV71-infected mice, the blockade of IL-6 with anti-IL-6 antibody (IL-6-Ab) restored the body weight loss, attenuated clinical scores, improved survival rates, reduced the disruption of neurofilament integrity, decreased cell apoptotic induction, and lowered levels of Caspase-3 cleavage. Similarly, in EV71-infected U251 cells, IL-6-Ab blocked EV71-induced IL-6 production and cell apoptosis in response to viral infection. Collectively, it’s exhibited TLR7 upregulation, IL-6 induction and astrocytic cell apoptosis in EV71-infected human brain. Taken together, we propose that EV71 infects astrocytes of the cerebral cortex in mice and human and triggers TLR7 signaling and IL-6 release, subsequently inducing neural pathogenesis in the brain. Enterovirus 71 (EV71) infection causes aseptic meningitis, poliomyelitis-like paralysis and fatal encephalitis in infants. Besides an immune receptor, toll-like receptor 7 (TLR7) serves as a death receptor in central nervous system (CNS). However, the role of TLR7 in EV71-induced neural pathogenesis remains ambiguous. This study reveals a distinct mechanism by which EV71 induces neurodegeneration via TLR7 and interleukin-6 (IL-6). Upon EV71 infection, TLR7-/- mice displayed less body weight loss, lower clinical score, and higher survival rate as compared with wild-type (WT) mice. Meanwhile, a severer histopathologic neurofilaments disruption, neurodegeneration and cell apoptosis were observed in brain of EV71-infected WT mice. IL-6 release, cell apoptosis, and Caspase-3 cleavage were attenuated by shRNA targeting TLR7 (shTLR7) in EV71-infected U251 cells. Moreover, anti-IL-6 antibody (IL-6-Ab) suppressed EV71-induced body weight loss, clinical score increase, and survival rate decrease as well as neurofilaments disruption and neurodegeneration in mice, and it also attenuated EV71-induced cell apoptosis and Caspase-3 cleavage in U251 cells. It’s retrospectively observed that TLR7 upregulation, IL-6 induction and astrocytic cell apoptosis in EV71-infected human brain. Therefore, TLR7 is required for neural pathogenesis by IL-6 induction upon EV71 infection.
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Affiliation(s)
- Zhen Luo
- Guangdong Key Laboratory of Virology, Institute of Medical Microbiology, Jinan University, Guangzhou, China
| | - Rui Su
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wenbiao Wang
- Guangdong Key Laboratory of Virology, Institute of Medical Microbiology, Jinan University, Guangzhou, China
| | - Yicong Liang
- Guangdong Key Laboratory of Virology, Institute of Medical Microbiology, Jinan University, Guangzhou, China
| | - Xiaofeng Zeng
- School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Muhammad Adnan Shereen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Nadia Bashir
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qi Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ling Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Kailang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yingle Liu
- Guangdong Key Laboratory of Virology, Institute of Medical Microbiology, Jinan University, Guangzhou, China
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jianguo Wu
- Guangdong Key Laboratory of Virology, Institute of Medical Microbiology, Jinan University, Guangzhou, China
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail:
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Chen CY, Shih YC, Hung YF, Hsueh YP. Beyond defense: regulation of neuronal morphogenesis and brain functions via Toll-like receptors. J Biomed Sci 2019; 26:90. [PMID: 31684953 PMCID: PMC6827257 DOI: 10.1186/s12929-019-0584-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 10/23/2019] [Indexed: 12/16/2022] Open
Abstract
Toll-like receptors (TLRs) are well known as critical pattern recognition receptors that trigger innate immune responses. In addition, TLRs are expressed in neurons and may act as the gears in the neuronal detection/alarm system for making good connections. As neuronal differentiation and circuit formation take place along with programmed cell death, neurons face the challenge of connecting with appropriate targets while avoiding dying or dead neurons. Activation of neuronal TLR3, TLR7 and TLR8 with nucleic acids negatively modulates neurite outgrowth and alters synapse formation in a cell-autonomous manner. It consequently influences neural connectivity and brain function and leads to deficits related to neuropsychiatric disorders. Importantly, neuronal TLR activation does not simply duplicate the downstream signal pathways and effectors of classical innate immune responses. The differences in spatial and temporal expression of TLRs and their ligands likely account for the diverse signaling pathways of neuronal TLRs. In conclusion, the accumulated evidence strengthens the idea that the innate immune system of neurons serves as an alarm system that responds to exogenous pathogens as well as intrinsic danger signals and fine-tune developmental processes of neurons.
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Affiliation(s)
- Chiung-Ya Chen
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan, Republic of China.
| | - Yi-Chun Shih
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan, Republic of China
| | - Yun-Fen Hung
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan, Republic of China
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan, Republic of China.
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Aurelian L, Balan I. GABA AR α2-activated neuroimmune signal controls binge drinking and impulsivity through regulation of the CCL2/CX3CL1 balance. Psychopharmacology (Berl) 2019; 236:3023-3043. [PMID: 31030249 DOI: 10.1007/s00213-019-05220-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/04/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND PURPOSE Toll-like receptors (TLRs) are a family of innate immune system receptors that respond to pathogen-derived and tissue damage-related ligands and are increasingly recognized for their impact on homeostasis and its dysregulation in the nervous system. TLR signaling participates in brain injury and addiction, but its role in the alcohol-seeking behavior, which initiates alcohol drinking, is still poorly understood. In this review, we discuss our findings designed to elucidate the potential contribution of the activated TLR4 signal located in neurons, on impulsivity and the predisposition to initiate alcohol drinking (binge drinking). RESULTS Our findings indicate that the TLR4 signal is innately activated in neurons from alcohol-preferring subjects, identifying a genetic contribution to the regulation of impulsivity and the alcohol-seeking propensity. Signal activation is through the non-canonical, previously unknown, binding of TLR4 to the α2 subunit of the γ-aminobutyric 2 acid A receptor (GABAAR α2). Activation is sustained by the stress hormone corticotrophin-releasing factor (CRF) and additional still poorly recognized ligand/scaffold proteins. Focus is on the effect of TLR4 signal activation on the balance between pro- and anti-inflammatory chemokines [chemokine (C-C motif) ligand 2 (CCL2)/chemokine (C-X3-C motif) ligand 1 (CX3CL1)] and its effect on binge drinking. CONCLUSION The results are discussed within the context of current findings on the distinct activation and functions of TLR signals located in neurons, as opposed to immune cells. They indicate that the balance between pro- and anti-inflammatory TLR4 signaling plays a major role in binge drinking. These findings have major impact on future basic and translational research, including the development of potential therapeutic and preventative strategies.
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Affiliation(s)
- Laure Aurelian
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Stanford University School of Medicine OFDD, Stanford, CA, 94305, USA.
| | - Irina Balan
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Protective effects of delayed intraventricular TLR7 agonist administration on cerebral white and gray matter following asphyxia in the preterm fetal sheep. Sci Rep 2019; 9:9562. [PMID: 31267031 PMCID: PMC6606639 DOI: 10.1038/s41598-019-45872-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/13/2019] [Indexed: 01/08/2023] Open
Abstract
Preterm brain injury is highly associated with inflammation, which is likely related in part to sterile responses to hypoxia-ischemia. We have recently shown that neuroprotection with inflammatory pre-conditioning in the immature brain is associated with induction of toll-like receptor 7 (TLR7). We therefore tested the hypothesis that central administration of a synthetic TLR7 agonist, gardiquimod (GDQ), after severe hypoxia-ischemia in preterm-equivalent fetal sheep would improve white and gray matter recovery. Fetal sheep at 0.7 of gestation received sham asphyxia or asphyxia induced by umbilical cord occlusion for 25 minutes, followed by a continuous intracerebroventricular infusion of GDQ or vehicle from 1 to 4 hours (total dose 1.8 mg/kg). Sheep were killed 72 hours after asphyxia for histology. GDQ significantly improved survival of immature and mature oligodendrocytes (2′,3′-cyclic-nucleotide 3′-phosphodiesterase, CNPase) and total oligodendrocytes (oligodendrocyte transcription factor 2, Olig-2) within the periventricular and intragyral white matter. There were reduced numbers of cells showing cleaved caspase-3 positive apoptosis and astrogliosis (glial fibrillary acidic protein, GFAP) in both white matter regions. Neuronal survival was increased in the dentate gyrus, caudate and medial thalamic nucleus. Central infusion of GDQ was associated with a robust increase in fetal plasma concentrations of the anti-inflammatory cytokines, interferon-β (IFN-β) and interleukin-10 (IL-10), with no significant change in the concentration of the pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α). In conclusion, delayed administration of the TLR7 agonist, GDQ, after severe hypoxia-ischemia in the developing brain markedly ameliorated white and gray matter damage, in association with upregulation of anti-inflammatory cytokines. These data strongly support the hypothesis that modulation of secondary inflammation may be a viable therapeutic target for injury of the preterm brain.
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