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Wu Z, Shen Z, Xu Y, Chen S, Xiao S, Ye J, Zhang H, Ma X, Zhu Y, Zhu X, Jiang Y, Fang J, Liu B, He X, Gao S, Shao X, Liu J, Fang J. A neural circuit associated with anxiety-like behaviors induced by chronic inflammatory pain and the anxiolytic effects of electroacupuncture. CNS Neurosci Ther 2024; 30:e14520. [PMID: 38018559 PMCID: PMC11017463 DOI: 10.1111/cns.14520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/14/2023] [Accepted: 10/22/2023] [Indexed: 11/30/2023] Open
Abstract
AIMS Negative emotions induced by chronic pain are a serious clinical problem. Electroacupuncture (EA) is a clinically proven safe and effective method to manage pain-related negative emotions. However, the circuit mechanisms underlying the effect of EA treatment on negative emotions remain unclear. METHODS Plantar injection of complete Freund's adjuvant (CFA) was performed to establish a rat model of chronic inflammatory pain-induced anxiety-like behaviors. Adeno-associated virus (AAV) tracing was used to identify excitatory synaptic transmission from the rostral anterior cingulate cortex (rACC) to the dorsal raphe nucleus (DRN). Employing chemogenetic approaches, we examined the role of the rACC-DRN circuit in chronic pain-induced anxiety-like behaviors and investigated whether EA could reverse chronic pain-induced dysfunctions of the rACC-DRN circuit and anxiety-like behaviors. RESULTS We found that chemogenetic activation of the rACC-DRN circuit alleviated CFA-induced anxiety-like behaviors, while chemogenetic inhibition of the rACC-DRN circuit resulted in short-term CFA-induced anxiety-like behaviors. Further research revealed that the development of CFA-induced anxiety-like behaviors was attributed to the dysfunction of rACC CaMKII neurons projecting to DRN serotonergic neurons (rACCCaMKII-DRN5-HT neurons) but not rACC CaMKII neurons projecting to DRN GABAergic neurons (rACCCaMKII-DRNGABA neurons). This is supported by the findings that chemogenetic activation of the rACCCaMKII-DRN5-HT circuit alleviates anxiety-like behaviors in rats with chronic pain, whereas neither chemogenetic inhibition nor chemogenetic activation of the rACCCaMKII-DRNGABA circuit altered CFA chronic pain-evoked anxiety-like behaviors in rats. More importantly, we found that EA could reverse chronic pain-induced changes in the activity of rACC CaMKII neurons and DRN 5-HTergic neurons and that chemogenetic inhibition of the rACCCaMKII-DRN5-HT circuit blocked the therapeutic effects of EA on chronic pain-induced anxiety-like behaviors. CONCLUSIONS Our data suggest that the reversal of rACCCaMKII-DRN5-HT circuit dysfunction may be a mechanism underlying the therapeutic effect of EA on chronic pain-induced anxiety-like behaviors.
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Affiliation(s)
- Zemin Wu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- Department of Acupuncture and Moxibustionthe First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Zui Shen
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yingling Xu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- Liangzhu LaboratoryZhejiang University Medical CenterHangzhouChina
| | - Shaozong Chen
- Institution of Acupuncture and Moxibustion, Shandong University of Traditional Chinese MedicineJinanChina
| | - Siqi Xiao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Jiayu Ye
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Haiyan Zhang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Xinyi Ma
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yichen Zhu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Xixiao Zhu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yongliang Jiang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Junfan Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Boyi Liu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Xiaofen He
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Shuzhong Gao
- Institution of Acupuncture and Moxibustion, Shandong University of Traditional Chinese MedicineJinanChina
| | - Xiaomei Shao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Jinggen Liu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- National Key Laboratory of Drug ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Jianqiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- Department of Acupuncture and Moxibustionthe First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
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Natsubori A, Kwon S, Honda Y, Kojima T, Karashima A, Masamoto K, Honda M. Serotonergic regulation of cortical neurovascular coupling and hemodynamics upon awakening from sleep in mice. J Cereb Blood Flow Metab 2024:271678X241238843. [PMID: 38477254 DOI: 10.1177/0271678x241238843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Neurovascular coupling (NVC) is the functional hyperemia of the brain responding to local neuronal activity. It is mediated by astrocytes and affected by subcortical ascending pathways in the cortex that convey information, such as sensory stimuli and the animal condition. Here, we investigate the influence of the raphe serotonergic system, a subcortical ascending arousal system in animals, on the modulation of cortical NVC and cerebral blood flow (CBF). Raphe serotonergic neurons were optogenically activated for 30 s, which immediately awakened the mice from non-rapid eye movement sleep. This caused a biphasic cortical hemodynamic change: a transient increase for a few seconds immediately after photostimulation onset, followed by a large progressive decrease during the stimulation period. Serotonergic neuron activation increased intracellular Ca2+ levels in cortical pyramidal neurons and astrocytes, demonstrating its effect on the NVC components. Pharmacological inhibition of cortical neuronal firing activity and astrocyte metabolic activity had small hypovolemic effects on serotonin-induced biphasic CBF changes, while blocking 5-HT1B receptors expressed primarily in cerebral vasculature attenuated the decreasing CBF phase. This suggests that serotonergic neuron activation leading to animal awakening could allow the NVC to exert a hyperemic function during a biphasic CBF response, with a predominant decrease in the cortex.
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Affiliation(s)
- Akiyo Natsubori
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Soojin Kwon
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yoshiko Honda
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takashi Kojima
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Akihiro Karashima
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, Sendai, Japan
| | - Kazuto Masamoto
- Dept. Mechanical and Intelligent Systems Engineering, Univ. of Electro-Communications, Tokyo, Japan
| | - Makoto Honda
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Nagao R, Mizutani Y, Shima S, Ueda A, Ito M, Yoshimoto J, Watanabe H. Correlations between serotonin impairments and clinical indices in multiple system atrophy. Eur J Neurol 2024; 31:e16158. [PMID: 38085271 DOI: 10.1111/ene.16158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 02/09/2024]
Abstract
BACKGROUND AND PURPOSE Multiple system atrophy (MSA) is a neurodegenerative disease with characteristic motor and autonomic symptoms. Impaired brain serotonergic innervation can be associated with various clinical indices of MSA; however, the relationship between clinical symptoms and cerebrospinal fluid (CSF) levels of 5-hydroxyindole acetic acid (5-HIAA), a main serotonin metabolite, has not been fully elucidated. METHODS To compare CSF 5-HIAA levels between patients with MSA and healthy controls, we included 33 controls and 69 MSA patients with either predominant parkinsonian or cerebellar ataxia subtypes. CSF 5-HIAA levels were measured using high-performance liquid chromatography. Additionally, we investigated correlations between CSF 5-HIAA and various clinical indices in 34 MSA patients. RESULTS CSF 5-HIAA levels were significantly lower in MSA patients than in controls (p < 0.0001). Probable MSA patients had lower CSF 5-HIAA levels than possible MSA patients (p < 0.001). In MSA patients, CSF 5-HIAA levels were inversely correlated with scores in Parts 1, 2, and 4 of the Unified Multiple System Atrophy Rating Scale, and with systolic and diastolic blood pressure in Part 3. Structural equation modeling revealed significant paths between serotonin and clinical symptoms, and significance was highest for activities of daily living, walking, and body sway. CONCLUSIONS Serotonin dysfunction, as assessed by CSF 5-HIAA levels, may implicate greater MSA severity.
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Affiliation(s)
- Ryunosuke Nagao
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Yasuaki Mizutani
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Sayuri Shima
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Akihiro Ueda
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Mizuki Ito
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Junichiro Yoshimoto
- Department of Biomedical Data Science, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
- International Center for Brain Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Hirohisa Watanabe
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
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Pan YD, Zhang Y, Zheng WY, Zhu MZ, Li HY, Ouyang WJ, Wen QQ, Zhu XH. Intermittent Hypobaric Hypoxia Ameliorates Autistic-Like Phenotypes in Mice. J Neurosci 2024; 44:e1665232023. [PMID: 38124211 PMCID: PMC10869151 DOI: 10.1523/jneurosci.1665-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/27/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by persistent deficits in social communication and stereotyped behaviors. Although major advances in basic research on autism have been achieved in the past decade, and behavioral interventions can mitigate the difficulties that individuals with autism experience, little is known about the many fundamental issues of the interventions, and no specific medication has demonstrated efficiency for the core symptoms of ASD. Intermittent hypobaric hypoxia (IHH) is characterized by repeated exposure to lowered atmospheric pressure and oxygen levels, which triggers multiple physiological adaptations in the body. Here, using two mouse models of ASD, male Shank3B -/- and Fmr1 -/y mice, we found that IHH training at an altitude of 5,000 m for 4 h per day, for 14 consecutive days, ameliorated autistic-like behaviors. Moreover, IHH training enhanced hypoxia inducible factor (HIF) 1α in the dorsal raphe nucleus (DRN) and activated the DRN serotonergic neurons. Infusion of cobalt chloride into the DRN, to mimic IHH in increasing HIF1α expression or genetically knockdown PHD2 to upregulate HIF1α expression in the DRN serotonergic neurons, alleviated autistic-like behaviors in Shank3B -/- mice. In contrast, downregulation of HIF1α in DRN serotonergic neurons induced compulsive behaviors. Furthermore, upregulating HIF1α in DRN serotonergic neurons increased the firing rates of these neurons, whereas downregulation of HIF1α in DRN serotonergic neurons decreased their firing rates. These findings suggest that IHH activated DRN serotonergic neurons via upregulation of HIF1α, and thus ameliorated autistic-like phenotypes, providing a novel therapeutic option for ASD.
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Affiliation(s)
- Yi-da Pan
- School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
| | - Yuan Zhang
- School of Psychology, Shenzhen University, Shenzhen 518060, China
| | - Wen-Ying Zheng
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
- School of Psychology, Shenzhen University, Shenzhen 518060, China
| | - Min-Zhen Zhu
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
| | - Huan-Yu Li
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
| | - Wen-Jie Ouyang
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
- School of Psychology, Shenzhen University, Shenzhen 518060, China
| | - Qin-Qing Wen
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Xin-Hong Zhu
- School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
- Research Center for Brain Health, Pazhou Lab, Guangzhou 510330, China
- School of Psychology, Shenzhen University, Shenzhen 518060, China
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
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Sawamura T, Yuki N, Aoki K, Horii K, Horii Y, Naitou K, Tsukamoto S, Shiina T, Shimizu Y. Alterations in descending brain-spinal pathways regulating colorectal motility in a rat model of Parkinson's disease. Am J Physiol Gastrointest Liver Physiol 2024; 326:G195-G204. [PMID: 38111988 DOI: 10.1152/ajpgi.00181.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/13/2023] [Accepted: 12/17/2023] [Indexed: 12/20/2023]
Abstract
Patients with Parkinson's disease (PD) often have constipation. It is assumed that a disorder of the regulatory mechanism of colorectal motility by the central nervous system is involved in the constipation, but this remains unclear. The aim of this study was to investigate whether central neural pathways can modulate colorectal motility in a rat model of PD. PD model rats were generated by injection of 6-hydroxydopamine into a unilateral medial forebrain bundle and destruction of dopaminergic neurons in the substantia nigra. Colorectal motility was measured in vivo in anesthetized rats. Intraluminal administration of capsaicin, as a noxious stimulus, induced colorectal motility in sham-operated rats but not in PD rats. Intrathecally administered dopamine (DA) and serotonin (5-HT), which mediate the prokinetic effect of capsaicin, at the L6-S1 levels enhanced colorectal motility in PD rats similarly to that in sham-operated rats. In PD rats, capsaicin enhanced colorectal motility only when a GABAA receptor antagonist was preadministered into the lumbosacral spinal cord. Capsaicin-induced colorectal motility was abolished by intrathecal administration of a D2-like receptor antagonist but not by administration of 5-HT2 and 5-HT3 receptor antagonists. These findings demonstrate that the inhibitory GABAergic component becomes operative and the stimulatory serotonergic component is suppressed in PD rats. The alteration of the central regulatory mechanism of colorectal motility is thought to be related to the occurrence of constipation in PD patients. Our findings provide a new insight into the pathogenesis of defecation disorders observed in PD.NEW & NOTEWORTHY In a rat model of Parkinson's disease, the component of descending brain-spinal pathways that regulate colorectal motility through a mediation of the lumbosacral defecation center was altered from stimulatory serotonergic neurons to inhibitory GABAergic neurons. Our findings suggest that chronic constipation in Parkinson's disease patients may be associated with alterations in central regulatory mechanisms of colorectal motility. The plasticity in the descending pathway regulating colorectal motility may contribute to other disease-related defecation abnormalities.
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Affiliation(s)
- Tomoya Sawamura
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Natsufu Yuki
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Kanae Aoki
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Kazuhiro Horii
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Division of Biological Principles, Department of Physiology, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Yuuki Horii
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Kiyotada Naitou
- Department of Basic Veterinary Science, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Shumpei Tsukamoto
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Takahiko Shiina
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Yasutake Shimizu
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
- Division of Animal Medical Science, Center for One Medicine Innovative Translational Research (COMIT), Gifu University Institute for Advanced Study, Gifu, Japan
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Dravecz N, Shaw T, Davies I, Brown C, Ormerod L, Vu G, Walker T, Taank T, Shirras AD, Broughton SJ. Corrigendum: Reduced insulin signaling targeted to serotonergic neurons but not other neuronal subtypes extends lifespan in Drosophila melanogaster. Front Aging Neurosci 2023; 15:1307495. [PMID: 37915830 PMCID: PMC10616946 DOI: 10.3389/fnagi.2023.1307495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 11/03/2023] Open
Abstract
[This corrects the article DOI: 10.3389/fnagi.2022.893444.].
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Susan J. Broughton
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
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Ahmadzadeh E, Dudink I, Walker DW, Sutherland AE, Pham Y, Stojanovska V, Polglase GR, Miller SL, Allison BJ. The medullary serotonergic centres involved in cardiorespiratory control are disrupted by fetal growth restriction. J Physiol 2023. [PMID: 37641535 DOI: 10.1113/jp284971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023] Open
Abstract
Fetal growth restriction (FGR) is associated with cardiovascular and respiratory complications after birth and beyond. Despite research showing a range of neurological changes following FGR, little is known about how FGR affects the brainstem cardiorespiratory control centres. The primary neurons that release serotonin reside in the brainstem cardiorespiratory control centres and may be affected by FGR. At two time points in the last trimester of sheep brain development, 110 and 127 days of gestation (0.74 and 0.86 of gestation), we assessed histopathological alterations in the brainstem cardiorespiratory control centres of the pons and medulla in early-onset FGR versus control fetal sheep. The FGR cohort were hypoxaemic and asymmetrically growth restricted. Compared to the controls, the brainstem of FGR fetuses exhibited signs of neuropathology, including elevated cell death and reduced cell proliferation, grey and white matter deficits, and evidence of oxidative stress and neuroinflammation. FGR brainstem pathology was predominantly observed in the medullary raphé nuclei, hypoglossal nucleus, nucleus ambiguous, solitary tract and nucleus of the solitary tract. The FGR groups showed imbalanced brainstem serotonin and serotonin 1A receptor abundance in the medullary raphé nuclei, despite evidence of increased serotonin staining within vascular regions of placentomes collected from FGR fetuses. Our findings demonstrate both early and adaptive brainstem neuropathology in response to placental insufficiency. KEY POINTS: Early-onset fetal growth restriction (FGR) was induced in fetal sheep, resulting in chronic fetal hypoxaemia. Growth-restricted fetuses exhibit persistent neuropathology in brainstem nuclei, characterised by disrupted cell proliferation and reduced neuronal cell number within critical centres responsible for the regulation of cardiovascular and respiratory functions. Elevated brainstem inflammation and oxidative stress suggest potential mechanisms contributing to the observed neuropathological changes. Both placental and brainstem levels of 5-HT were found to be impaired following FGR.
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Affiliation(s)
- Elham Ahmadzadeh
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Ingrid Dudink
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Amy E Sutherland
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Yen Pham
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Beth J Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
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Dravecz N, Shaw T, Davies I, Brown C, Ormerod L, Vu G, Walker T, Taank T, Shirras AD, Broughton SJ. Reduced Insulin Signaling Targeted to Serotonergic Neurons but Not Other Neuronal Subtypes Extends Lifespan in Drosophila melanogaster. Front Aging Neurosci 2022; 14:893444. [PMID: 35865744 PMCID: PMC9294736 DOI: 10.3389/fnagi.2022.893444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
Reduced Insulin/IGF-like signaling (IIS) plays an evolutionarily conserved role in improving longevity and some measures of health-span in model organisms. Recent studies, however, have found a disconnection between lifespan extension and behavioral health-span. We have previously shown that reduction of IIS in Drosophila neurons extends female lifespan but does not improve negative geotaxis senescence and has a detrimental effect on exploratory walking senescence in both sexes. We hypothesize that individual neuronal subtypes respond differently to IIS changes, thus the behavioral outcomes of pan-neuronal IIS reduction are the balance of positive, negative and neutral functional effects. In order to further understand how reduced IIS in neurons independently modulates lifespan and locomotor behavioral senescence we expressed a dominant negative Insulin receptor transgene selectively in individual neuronal subtypes and measured the effects on lifespan and two measures of locomotor senescence, negative geotaxis and exploratory walking. IIS reduction in cholinergic, GABAergic, dopaminergic, glutamatergic, and octopaminergic neurons was found to have either no affect or a detrimental effect on lifespan and locomotor senescence. However, reduction of IIS selectively in serotonergic neurons resulted in extension of lifespan in females with no effect on locomotor senescence. These data indicate that individual neuronal subtypes respond differently to IIS changes in the modulation of lifespan and locomotor senescence, and identify a specific role for the insulin receptor in serotonergic neurons in the modulation of lifespan.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Susan J. Broughton
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
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Cheng Y, Song N, Ge R, Dai Y. Serotonergic Modulation of Persistent Inward Currents in Serotonergic Neurons of Medulla in ePet-EYFP Mice. Front Neural Circuits 2021; 15:657445. [PMID: 33889077 PMCID: PMC8055846 DOI: 10.3389/fncir.2021.657445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/15/2021] [Indexed: 11/23/2022] Open
Abstract
Serotonergic (5-HT) neurons in the medulla play multiple functional roles associated with many symptoms and motor activities. The descending serotonergic pathway from medulla is essential for initiating locomotion. However, the ionic properties of 5-HT neurons in the medulla remain unclear. Using whole-cell patch-clamp technique, we studied the biophysical and modulatory properties of persistent inward currents (PICs) in 5-HT neurons of medulla in ePet-EYFP transgenic mice (P3–P6). PICs were recorded by a family of voltage bi-ramps (10-s duration, 40-mV peak step), and the ascending and descending PICs were mirrored to analyze the PIC hysteresis. PICs were found in 77% of 5-HT neurons (198/258) with no significant difference between parapyramidal region (n = 107) and midline raphe nuclei (MRN) (n = 91) in either PIC onset (−47.4 ± 10 mV and −48.7 ± 7 mV; P = 0.44) or PIC amplitude (226.9 ± 138 pA and 259.2 ± 141 pA; P = 0.29). Ninety-six percentage (191/198) of the 5-HT neurons displayed counterclockwise hysteresis and four percentage (7/198) exhibited the clockwise hysteresis. The composite PICs could be differentiated as calcium component (Ca_PIC) by bath application of nimodipine (25 μM), sodium component (Na_PIC) by tetrodotoxin (TTX, 2 μM), and TTX- and dihydropyridine-resistance component (TDR_PIC) by TTX and nimodipine. Ca_PIC, Na_PIC and TDR_PIC all contributed to upregulation of excitability of 5-HT neurons. 5-HT (15 μM) enhanced the PICs, including a 26% increase in amplitude of the compound currents of Ca_PIC and TDR_PIC (P < 0.001, n = 9), 3.6 ± 5 mV hyperpolarization of Na_PIC and TDR_PIC onset (P < 0.05, n = 12), 30% increase in amplitude of TDR_PIC (P < 0.01), and 2.0 ± 3 mV hyperpolarization of TDR_PIC onset (P < 0.05, n = 18). 5-HT also facilitated repetitive firing of 5-HT neurons through modulation of composite PIC, Na_PIC and TDR_PIC, and Ca_PIC and TDR_PIC, respectively. In particular, the high voltage-activated TDR_PIC facilitated the repetitive firing in higher membrane potential, and this facilitation could be amplified by 5-HT. Morphological data analysis indicated that the dendrites of 5-HT neurons possessed dense spherical varicosities intensively crossing 5-HT neurons in medulla. We characterized the PICs in 5-HT neurons and unveiled the mechanism underlying upregulation of excitability of 5-HT neurons through serotonergic modulation of PICs. This study provided insight into channel mechanisms responsible for the serotonergic modulation of serotonergic neurons in brainstem.
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Affiliation(s)
- Yi Cheng
- School of Physical Education, Yunnan University, Kunming, China
| | - Nan Song
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, School of Physical Education and Health Care, East China Normal University, Shanghai, China
| | - Renkai Ge
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, China.,School of Physical Education and Health Care, East China Jiaotong University, Nanchang, China
| | - Yue Dai
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, School of Physical Education and Health Care, East China Normal University, Shanghai, China.,Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, China
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Paul N, Raymond J, Lumbreras S, Bartsch D, Weber T, Lau T. Activation of the glucocorticoid receptor rapidly triggers calcium-dependent serotonin release in vitro. CNS Neurosci Ther 2021; 27:753-764. [PMID: 33715314 PMCID: PMC8193689 DOI: 10.1111/cns.13634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/22/2021] [Accepted: 02/25/2021] [Indexed: 12/01/2022] Open
Abstract
Aims Glucocorticoids rapidly provoke serotonin (5‐HT) release in vivo. We aimed to investigate molecular mechanisms of glucocorticoid receptor (GR)‐triggered 5‐HT release. Methods Employing 1C11 cells to model 5‐HT neurotransmission, immunofluorescence and Pearson's Correlation Coefficient were used to analyze colocalization of GR, 5‐HT, vesicle membrane protein synaptotagmin 1 and vesicle dye FM4‐64FX. FFN511 and FM4‐64FX dyes as well as calcium imaging were used to visualize vesicular 5‐HT release upon application of GR agonist dexamethasone, GR antagonist mifepristone and voltage‐gated calcium channel (VGCC) inhibitors. Results GR, 5‐HT, synaptotagmin 1 and FM4‐64FX showed overlapping staining patterns, with Pearson's Correlation Coefficient indicating colocalization. Similarly to potassium chloride, dexamethasone caused a release of FFN511 and uptake of FM4‐64FX, indicating vesicular 5‐HT release. Mifepristone, calcium depletion and inhibition of L‐type VGCC significantly diminished dexamethasone‐induced vesicular 5‐HT release. Conclusions In close proximity to 5‐HT releasing sites, activated GR rapidly triggers L‐type VGCC‐dependent vesicular 5‐HT release. These findings provide a better understanding of the interrelationship between glucocorticoids and 5‐HT release.
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Affiliation(s)
- Nicolas Paul
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Justine Raymond
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Sara Lumbreras
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dusan Bartsch
- Transgenic Models, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Tillmann Weber
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,MEDIAN Klinik Wilhelmsheim, Oppenweiler, Germany
| | - Thorsten Lau
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Department of Translational Brain Research, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Hector Institute for Translational Brain Research, Mannheim, Germany.,German Cancer Research Center, Heidelberg, Germany
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11
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Cheng Y, Zhang Q, Dai Y. Sequential activation of multiple persistent inward currents induces staircase currents in serotonergic neurons of medulla in ePet-EYFP mice. J Neurophysiol 2019; 123:277-288. [PMID: 31721638 DOI: 10.1152/jn.00623.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Persistent inward currents (PICs) are widely reported in rodent spinal neurons. A distinctive pattern observed recently is staircase-like PICs induced by voltage ramp in serotonergic neurons of mouse medulla. The mechanism underlying this pattern of PICs is unclear. Combining electrophysiological, pharmacological, and computational approaches, we investigated the staircase PICs in serotonergic neurons of medulla in ePet-EYFP transgenic mice (postnatal days 1-7). Staircase PICs induced by 10-s voltage biramps were observed in 70% of serotonergic neurons (n = 73). Staircase PICs activated at -48.8 ± 5 mV and consisted of two components, with the first PIC of 45.8 ± 51 pA and the second PIC of 197.3 ± 126 pA (n = 51). Staircase PICs were also composed of low-voltage-activated sodium PIC (Na-PIC; onset -46.2 ± 5 mV, n = 34), high-voltage-activated calcium PIC (Ca-PIC; onset -29.3 ± 6 mV, n = 23), and high-voltage-activated tetrodotoxin (TTX)- and dihydropyridine-resistant sodium PIC (TDR-PIC; onset -16.8 ± 4 mV, n = 28). Serotonergic neurons expressing Na-PIC, Ca-PIC, and TDR-PIC were evenly distributed in medulla. Bath application of 1-2 μM TTX blocked the first PIC and decreased the second PIC by 36% (n = 23, P < 0.05). Nimodipine (25 μM) reduced the second PIC by 38% (n = 34, P < 0.001) without altering the first PIC. TTX and nimodipine removed the first PIC and reduced the second PIC by 59% (n = 28, P < 0.01). A modeling study mimicked the staircase PICs and verified experimental conclusions that sequential activation of Na-PIC, Ca-PIC, and TDR-PIC in order of voltage thresholds induced staircase PICs in serotonergic neurons. Further experimental results suggested that the multiple components of staircase PICs play functional roles in regulating excitability of serotonergic neurons in medulla.NEW & NOTEWORTHY Staircase persistent inward currents (PICs) are mediated by activation of L-type calcium channels in dendrites of mouse spinal motoneurons. A novel mechanism is explored in this study. Here we report that the staircase PICs are mediated by sequentially activating sodium and calcium PICs in serotonergic neurons of mouse medulla.
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Affiliation(s)
- Yi Cheng
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, School of Physical Education and Health Care, East China Normal University, Shanghai, People's Republic of China
| | - Qiang Zhang
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, People's Republic of China
| | - Yue Dai
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, School of Physical Education and Health Care, East China Normal University, Shanghai, People's Republic of China.,Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, People's Republic of China
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12
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Lloret-Fernández C, Maicas M, Mora-Martínez C, Artacho A, Jimeno-Martín Á, Chirivella L, Weinberg P, Flames N. A transcription factor collective defines the HSN serotonergic neuron regulatory landscape. eLife 2018; 7:32785. [PMID: 29553368 PMCID: PMC5916565 DOI: 10.7554/elife.32785] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/16/2018] [Indexed: 01/02/2023] Open
Abstract
Cell differentiation is controlled by individual transcription factors (TFs) that together activate a selection of enhancers in specific cell types. How these combinations of TFs identify and activate their target sequences remains poorly understood. Here, we identify the cis-regulatory transcriptional code that controls the differentiation of serotonergic HSN neurons in Caenorhabditis elegans. Activation of the HSN transcriptome is directly orchestrated by a collective of six TFs. Binding site clusters for this TF collective form a regulatory signature that is sufficient for de novo identification of HSN neuron functional enhancers. Among C. elegans neurons, the HSN transcriptome most closely resembles that of mouse serotonergic neurons. Mouse orthologs of the HSN TF collective also regulate serotonergic differentiation and can functionally substitute for their worm counterparts which suggests deep homology. Our results identify rules governing the regulatory landscape of a critically important neuronal type in two species separated by over 700 million years.
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Affiliation(s)
- Carla Lloret-Fernández
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Miren Maicas
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Carlos Mora-Martínez
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Alejandro Artacho
- Departamento de Genómica y Salud, Centro Superior de Investigación en Salud Pública, FISABIO, Valencia, Spain
| | - Ángela Jimeno-Martín
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Laura Chirivella
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Peter Weinberg
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University Medical Center, New York, United States
| | - Nuria Flames
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
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Abstract
Ratiometric imaging can quantitatively measure changes in cellular analyte concentrations using specially designed fluorescent labels. We describe a label-free ratiometric imaging technique for direct detection of changes in intravesicular serotonin concentration in live cells. At higher concentrations, serotonin forms transient oligomers whose ultraviolet emission is shifted to longer wavelengths. We access the ultraviolet/blue emission using relatively benign three-photon excitation and split it into two imaging channels, whose ratio reports the concentration. The technique is sensitive at a physiologically relevant concentration range (10-150 mM serotonin). As a proof of principle, we measure the increase of intravesicular serotonin concentration with the addition of external serotonin. In general, since emission spectra of molecules are often sensitive to concentration, our method may be applicable to other natively fluorescent intracellular molecules which are present at high concentrations.
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Affiliation(s)
- Anand Kant Das
- Department
of Chemical Sciences, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba,
Mumbai 400005, India
| | - Barun Kumar Maity
- Department
of Chemical Sciences, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba,
Mumbai 400005, India
| | - Dayana Surendran
- Department
of Chemical Sciences, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba,
Mumbai 400005, India
| | - Umakanta Tripathy
- Department
of Applied Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004 Jharkhand, India
| | - Sudipta Maiti
- Department
of Chemical Sciences, Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Colaba,
Mumbai 400005, India
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14
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Pacini G, Marino A, Migliarini S, Brilli E, Pelosi B, Maddaloni G, Pratelli M, Pellegrino M, Ferrari A, Pasqualetti M. A Tph2 GFP Reporter Stem Cell Line To Model in Vitro and in Vivo Serotonergic Neuron Development and Function. ACS Chem Neurosci 2017; 8:1043-1052. [PMID: 28029782 DOI: 10.1021/acschemneuro.6b00403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Modeling biological systems in vitro has contributed to clarification of complex mechanisms in simplified and controlled experimental conditions. Mouse embryonic stem (mES) cells can be successfully differentiated toward specific neuronal cell fates, thus representing an attractive tool to dissect, in vitro, mechanisms that underlie complex neuronal features. In this study, we generated and characterized a reporter mES cell line, called Tph2GFP, in which the vital reporter GFP replaces the tryptophan hydroxylase 2 (Tph2) gene. Tph2GFP mES cells selectively express GFP upon in vitro differentiation toward the serotonergic fate, they synthesize serotonin, possess excitable membranes, and show the typical morphological, morphometrical, and molecular features of in vivo serotonergic neurons. Thanks to the vital reporter GFP, we highlighted by time-lapse video microscopy several dynamic processes such as cell migration and axonal outgrowth in living cultures. Finally, we demonstrated that predifferentiated Tph2GFP cells are able to terminally differentiate, integrate, and innervate the host brain when grafted in vivo. On the whole, the present study introduces the Tph2GFP mES cell line as a useful tool allowing accurate developmental and dynamic studies and representing a reliable platform for the study of serotonergic neurons in health and disease.
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Affiliation(s)
- Giulia Pacini
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Attilio Marino
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Sara Migliarini
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Elisa Brilli
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Barbara Pelosi
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Giacomo Maddaloni
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Marta Pratelli
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
| | - Mario Pellegrino
- Dipartimento
di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, University of Pisa, 56126 Pisa, Italy
- Istituto Nazionale di Ottica, National Research Council (CNR), 56124 Pisa, Italy
| | - Aldo Ferrari
- ETH Zurich, Laboratory of Thermodynamics in
Emerging Technologies, 8092 Zurich, Switzerland
| | - Massimo Pasqualetti
- Department
of Biology, Unit of Cell and Developmental Biology, University of Pisa, 56127 Pisa, Italy
- Center
for Neuroscience and Cognitive Systems, Istituto Italiano di Tecnologia, 38068 Rovereto (TN), Italy
- Neuroscience Institute, National Research Council (CNR), 56124 Pisa, Italy
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15
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Mlinar B, Montalbano A, Piszczek L, Gross C, Corradetti R. Firing Properties of Genetically Identified Dorsal Raphe Serotonergic Neurons in Brain Slices. Front Cell Neurosci 2016; 10:195. [PMID: 27536220 PMCID: PMC4971071 DOI: 10.3389/fncel.2016.00195] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 07/22/2016] [Indexed: 11/13/2022] Open
Abstract
Tonic spiking of serotonergic neurons establishes serotonin levels in the brain. Since the first observations, slow regular spiking has been considered as a defining feature of serotonergic neurons. Recent studies, however, have revealed the heterogeneity of serotonergic neurons at multiple levels, comprising their electrophysiological properties, suggesting the existence of functionally distinct cellular subpopulations. In order to examine in an unbiased manner whether serotonergic neurons of the dorsal raphe nucleus (DRN) are heterogeneous, we used a non-invasive loose-seal cell-attached method to record α1 adrenergic receptor-stimulated spiking of a large sample of neurons in brain slices obtained from transgenic mice lines that express fluorescent marker proteins under the control of serotonergic system-specific Tph2 and Pet-1 promoters. We found wide homogeneous distribution of firing rates, well fitted by a single Gaussian function (r (2) = 0.93) and independent of anatomical location (P = 0.45), suggesting that in terms of intrinsic firing properties, serotonergic neurons in the DRN represent a single cellular population. Characterization of the population in terms of spiking regularity was hindered by its dependence on the firing rate. For instance, the coefficient of variation of the interspike intervals (ISI), a common measure of spiking irregularity, is of limited usefulness since it correlates negatively with the firing rate (r = -0.33, P < 0.0001). Nevertheless, the majority of neurons exhibited regular, pacemaker-like activity, with coefficient of variance of the ISI lower than 0.5 in ~97% of cases. Unexpectedly, a small percentage of neurons (~1%) exhibited a particular spiking pattern, characterized by low frequency (~0.02-0.1 Hz) oscillations in the firing rate. Transitions between regular and oscillatory firing were observed, suggesting that the oscillatory firing is an alternative firing pattern of serotonergic neurons.
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Affiliation(s)
- Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Children's Health, University of Florence Florence, Italy
| | - Alberto Montalbano
- Department of Neuroscience, Psychology, Drug Research and Children's Health, University of Florence Florence, Italy
| | - Lukasz Piszczek
- Mouse Biology Unit, European Molecular Biology Laboratory Monterotondo, Italy
| | - Cornelius Gross
- Mouse Biology Unit, European Molecular Biology Laboratory Monterotondo, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Children's Health, University of Florence Florence, Italy
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Inoue T, Yamashita T, Agata K. Thermosensory signaling by TRPM is processed by brain serotonergic neurons to produce planarian thermotaxis. J Neurosci 2014; 34:15701-14. [PMID: 25411498 DOI: 10.1523/JNEUROSCI.5379-13.2014] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
For most organisms, sensitive recognition of even slight changes in environmental temperature is essential for adjusting their behavioral strategies to ensure homeostasis and survival. However, much remains to be understood about the molecular and cellular processes that regulate thermosensation and the corresponding behavioral responses. Planarians display clear thermotaxis, although they have a relatively simple brain. Here, we devised a quantitative thermotaxis assay and unraveled a neural pathway involved in planarian thermotaxis by combinatory behavioral assays and RNAi analysis. We found that thermosensory neurons that expressed a planarian Dugesia japonica homolog of the Transient Receptor Potential Melastatin family a (DjTRPMa) gene were required for the thermotaxis. Interestingly, although these thermosensory neurons are distributed throughout their body, planarians with a dysfunctional brain due to regeneration-dependent conditional gene knockdown (Readyknock) of the synaptotagmin gene completely lost their thermotactic behavior. These results suggest that brain function is required as a central processor for the thermosensory response. Therefore, we investigated the type(s) of brain neurons involved in processing the thermal signals by gene knockdown of limiting enzymes for neurotransmitter biosynthesis in the brain. We found that serotonergic neurons with dendrites that were elongated toward DjTRPMa-expressing thermosensory neurons might be required for the processing of signals from thermosensory neurons that results in thermotaxis. These results suggest that serotonergic neurons in the brain may interact with thermosensory neurons activated by TRPM ion channels to produce thermotaxis in planarians.
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17
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Vernay B, Koch M, Vaccarino F, Briscoe J, Simeone A, Kageyama R, Ang SL. Otx2 regulates subtype specification and neurogenesis in the midbrain. J Neurosci 2005; 25:4856-67. [PMID: 15888661 PMCID: PMC6724764 DOI: 10.1523/jneurosci.5158-04.2005] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 03/12/2005] [Accepted: 03/13/2005] [Indexed: 11/21/2022] Open
Abstract
The transcription factor Otx2 is required to determine mesencephalic versus metencephalic (cerebellum/pons) territory during embryogenesis. This function of Otx2 primarily involves positioning and maintaining the mid-hindbrain organizer at the border between midbrain and anterior hindbrain. Otx2 expression is maintained long after this organizer is established. We therefore generated conditional mutants of Otx2 using the Cre/loxP system to study later roles during rostral brain development. For inactivation of Otx2 in neuronal progenitor cells, we crossed Otx2(flox/flox) animals with Nestin-Cre transgenic animals. In Nestin-Cre/+; Otx2(flox/flox) embryos, Otx2 activity was lost from the ventral midbrain starting at embryonic day 10.5 (E10.5). In these mutant embryos, the mid-hindbrain organizer was properly positioned at E12.5, although Otx2 is absent from the midbrain. Hence, the Nestin-Cre/+; Otx2(flox/flox) animals represent a novel mouse model for studying the role of Otx2 in the midbrain, independently of abnormal development of the mid-hindbrain organizer. Our data demonstrate that Otx2 controls the development of several neuronal populations in the midbrain by regulating progenitor identity and neurogenesis. Dorsal midbrain progenitors ectopically expressed Math1 and generate an ectopic cerebellar-like structure. Similarly, Nkx2.2 ectopic expression ventrally into tegmentum progenitors is responsible for the formation of serotonergic neurons and hypoplasia of the red nucleus in the midbrain. In addition, we discovered a novel role for Otx2 in regulating neurogenesis of dopaminergic neurons. Altogether, these results demonstrate that Otx2 is required from E10.5 onward to regulate neuronal subtype identity and neurogenesis in the midbrain.
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Affiliation(s)
- Bertrand Vernay
- Institut de Génétique et de Biologie Moléculaire et Cellulaire/Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale, Université Louis Pasteur, 67404 Illkirch cedex, Strasbourg, France
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Lee G, Hall JC. Abnormalities of male-specific FRU protein and serotonin expression in the CNS of fruitless mutants in Drosophila. J Neurosci 2001; 21:513-26. [PMID: 11160431 PMCID: PMC6763814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The fruitless gene in Drosophila produces male-specific protein (FRU(M)) involved in the control of courtship. FRU(M) spatial and temporal patterns were examined in fru mutants that exhibit aberrant male courtship. Chromosome breakpoints at the locus eliminated FRU(M). Homozygous viable mutants exhibited an intriguing array of defects. In fru(1) males, there were absences of FRU(M)-expressing neuronal clusters or stained cells within certain clusters, reductions of signal intensities in others, and ectopic FRU(M) expression in novel cells. fru(2) males exhibited an overall decrement of FRU(M) expression in all neurons normally expressing the gene. fru(4) and fru(sat) mutants only produced FRU(M) in small numbers of neurons at extremely low levels, and no FRU(M) signals were detected in fru(3) males. This array of abnormalities was inferred to correlate with the varying behavioral defects exhibited by these mutants. Such abnormalities include courtship among males, which has been hypothesized to involve anomalies of serotonin (5-HT) function in the brain. However, double-labeling uncovered no coexpression of FRU(M) and 5-HT in brain neurons. Yet, a newly identified set of sexually dimorphic FRU(M)/5-HT-positive neurons was identified in the abdominal ganglion of adult males. These sexually dimorphic neurons (s-Abg) project toward regions of the abdomen involved in male reproduction. The s-Abg neurons and the proximal extents of their axons were unstained or absent in wild-type females and exhibited subnormal or no 5-HT immunoreactivity in certain fru-mutant males, indicating that fruitless controls the formation of these cells or 5-HT production in them.
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Affiliation(s)
- G Lee
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454, USA
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