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Fan W, Liu L, Yin Y, Zhang J, Qiu Z, Guo J, Li G. Protein nanoparticles induce the activation of voltage-dependent non-selective ion channels to modulate biological osmotic pressure in cytotoxic cerebral edema. Front Pharmacol 2024; 15:1361733. [PMID: 39130645 PMCID: PMC11310023 DOI: 10.3389/fphar.2024.1361733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 07/08/2024] [Indexed: 08/13/2024] Open
Abstract
Introduction Cytotoxic cerebral edema is a serious complication associated with cerebral ischemic stroke and is widely treated using the hypertonic dehydrant. Here, we propose, for the first time, the decrease of intracellular osmosis as a treatment strategy for alleviating cytotoxic cerebral edema. Methods We established a fluorescence resonance energy transfer-based intermediate filament tension probe for the study and in situ evaluation of osmotic gradients, which were examined in real-time in living cells from primary cultures as well as cell lines. The MCAO rat model was used to confirm our therapy of cerebral edema. Results Depolymerization of microfilaments/microtubules and the production of NLRP3 inflammasome resulted in an abundance of protein nanoparticles (PNs) in the glutamate-induced swelling of astrocytes. PNs induced changes in membrane potential and intracellular second messengers, thereby contributing to hyper-osmosis and the resultant astrocyte swelling via the activation of voltage-dependent nonselective ion channels. Therefore, multiple inhibitors of PNs, sodium and chloride ion channels were screened as compound combinations, based on a decrease in cell osmosis and astrocyte swelling, which was followed by further confirmation of the effectiveness of the compound combination against alleviated cerebral edema after ischemia. Discussion The present study proposes new pathological mechanisms underlying "electrophysiology-biochemical signal-osmotic tension," which are responsible for cascade regulation in cerebral edema. It also explores various compound combinations as a potential treatment strategy for cerebral edema, which act by multi-targeting intracellular PNs and voltage-dependent nonselective ion flux to reduce astrocyte osmosis.
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Affiliation(s)
- Wei Fan
- Department of Anesthesiology, Huaian First People's Hospital, Nanjing Medical University, Huaian, China
| | - Liming Liu
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yuxuan Yin
- Department of Anesthesiology, Huaian First People's Hospital, Nanjing Medical University, Huaian, China
| | - Jiayi Zhang
- Department of Anesthesiology, Huaian First People's Hospital, Nanjing Medical University, Huaian, China
| | - Zhaoshun Qiu
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jun Guo
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Guangming Li
- Department of Anesthesiology, Huaian First People's Hospital, Nanjing Medical University, Huaian, China
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Parikh A, Krogman W, Walker J. The impact of volatile anesthetics and propofol on phosphatidylinositol 4,5-bisphosphate signaling. Arch Biochem Biophys 2024; 757:110045. [PMID: 38801966 DOI: 10.1016/j.abb.2024.110045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/29/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2), as well as other anionic phospholipids, play a pivotal role in various cellular processes, including ion channel regulation, receptor trafficking, and intracellular signaling pathways. The binding of volatile anesthetics and propofol to PIP2 leads to alterations in PIP2-mediated signaling causing modulation of ion channels such as ɣ-aminobutyric acid type A (GABAA) receptors, voltage-gated calcium channels, and potassium channels through various mechanisms. Additionally, the interaction between anionic phospholipids and G protein-coupled receptors plays a critical role in various anesthetic pathways, with these anesthetic-induced changes impacting PIP2 levels which cause cascading effects on receptor trafficking, including GABAA receptor internalization. This comprehensive review of various mechanisms of interaction provides insights into the intricate interplay between PIP2 signaling and anesthetic-induced changes, shedding light on the molecular mechanisms underlying anesthesia.
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Affiliation(s)
- Ayaan Parikh
- Wichita Collegiate School, Wichita, KS. 9115 E 13th St N, Wichita, KS, 67206, USA.
| | - William Krogman
- University of Kansas School of Medicine-Wichita, Wichita, KS, USA; Department of Anesthesiology, 929 N St Francis, Room 8079, Wichita, KS, 67214, USA
| | - James Walker
- University of Kansas School of Medicine-Wichita, Wichita, KS, USA; Department of Anesthesiology, 929 N St Francis, Room 8079, Wichita, KS, 67214, USA
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3
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Liu X, Sun X, Guo C, Huang ZF, Chen YR, Feng FM, Wu LJ, Chen WX. Untargeted urine metabolomics and machine learning provide potential metabolic signatures in children with autism spectrum disorder. Front Psychiatry 2024; 15:1261617. [PMID: 38445087 PMCID: PMC10912307 DOI: 10.3389/fpsyt.2024.1261617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 01/19/2024] [Indexed: 03/07/2024] Open
Abstract
Background Complementary to traditional biostatistics, the integration of untargeted urine metabolomic profiling with Machine Learning (ML) has the potential to unveil metabolic profiles crucial for understanding diseases. However, the application of this approach in autism remains underexplored. Our objective was to delve into the metabolic profiles of autism utilizing a comprehensive untargeted metabolomics platform coupled with ML. Methods Untargeted metabolomics quantification (UHPLC/Q-TOF-MS) was performed for urine analysis. Feature selection was conducted using Lasso regression, and logistic regression, support vector machine, random forest, and extreme gradient boosting were utilized for significance stratification. Pathway enrichment analysis was performed to identify metabolic pathways associated with autism. Results A total of 52 autistic children and 40 typically developing children were enrolled. Lasso regression identified ninety-two urinary metabolites that significantly differed between the two groups. Distinct metabolites, such as prostaglandin E2, phosphonic acid, lysine, threonine, and phenylalanine, were revealed to be associated with autism through the application of four different ML methods (p<0.05). The alterations observed in the phosphatidylinositol and inositol phosphate metabolism pathways were linked to the pathophysiology of autism (p<0.05). Conclusion Significant urinary metabolites, including prostaglandin E2, phosphonic acid, lysine, threonine, and phenylalanine, exhibit associations with autism. Additionally, the involvement of the phosphatidylinositol and inositol phosphate pathways suggests their potential role in the pathophysiology of autism.
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Affiliation(s)
- Xian Liu
- Department of Children’s and Adolescent Health, College of Public Health, Harbin Medical University, Harbin, China
- Division of Birth Cohort Study, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
| | - Xin Sun
- Clinical Research and Innovation Center, Xinhua Hospital Affiliated with Shanghai Jiao Tong University, Shanghai, China
| | - Cheng Guo
- The Assessment and Intervention Center for Autistic Children, Guangzhou Women and Children’s Medical Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
- Department of Neurology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
| | - Zhi-Fang Huang
- The Assessment and Intervention Center for Autistic Children, Guangzhou Women and Children’s Medical Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
- Department of Neurology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
| | - Yi-Ru Chen
- The Assessment and Intervention Center for Autistic Children, Guangzhou Women and Children’s Medical Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
- Department of Neurology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
| | - Fang-Mei Feng
- The Assessment and Intervention Center for Autistic Children, Guangzhou Women and Children’s Medical Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
- Department of Neurology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
| | - Li-Jie Wu
- Department of Children’s and Adolescent Health, College of Public Health, Harbin Medical University, Harbin, China
| | - Wen-Xiong Chen
- The Assessment and Intervention Center for Autistic Children, Guangzhou Women and Children’s Medical Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
- Department of Neurology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
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Khouma A, Moeini MM, Plamondon J, Richard D, Caron A, Michael NJ. Histaminergic regulation of food intake. Front Endocrinol (Lausanne) 2023; 14:1202089. [PMID: 37448468 PMCID: PMC10338010 DOI: 10.3389/fendo.2023.1202089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/06/2023] [Indexed: 07/15/2023] Open
Abstract
Histamine is a biogenic amine that acts as a neuromodulator within the brain. In the hypothalamus, histaminergic signaling contributes to the regulation of numerous physiological and homeostatic processes, including the regulation of energy balance. Histaminergic neurons project extensively throughout the hypothalamus and two histamine receptors (H1R, H3R) are strongly expressed in key hypothalamic nuclei known to regulate energy homeostasis, including the paraventricular (PVH), ventromedial (VMH), dorsomedial (DMH), and arcuate (ARC) nuclei. The activation of different histamine receptors is associated with differential effects on neuronal activity, mediated by their different G protein-coupling. Consequently, activation of H1R has opposing effects on food intake to that of H3R: H1R activation suppresses food intake, while H3R activation mediates an orexigenic response. The central histaminergic system has been implicated in atypical antipsychotic-induced weight gain and has been proposed as a potential therapeutic target for the treatment of obesity. It has also been demonstrated to interact with other major regulators of energy homeostasis, including the central melanocortin system and the adipose-derived hormone leptin. However, the exact mechanisms by which the histaminergic system contributes to the modification of these satiety signals remain underexplored. The present review focuses on recent advances in our understanding of the central histaminergic system's role in regulating feeding and highlights unanswered questions remaining in our knowledge of the functionality of this system.
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Affiliation(s)
- Axelle Khouma
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
- Faculté de Pharmacie, Université Laval, Québec, QC, Canada
| | - Moein Minbashi Moeini
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
- Faculté de Pharmacie, Université Laval, Québec, QC, Canada
| | - Julie Plamondon
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
| | - Denis Richard
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
- Faculté de Medicine, Université Laval, Québec, QC, Canada
| | - Alexandre Caron
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
- Faculté de Pharmacie, Université Laval, Québec, QC, Canada
- Montreal Diabetes Research Center, Montreal, QC, Canada
| | - Natalie Jane Michael
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, QC, Canada
- Faculté de Pharmacie, Université Laval, Québec, QC, Canada
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5
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Marini P, Cowie P, Ayar A, Bewick GS, Barrow J, Pertwee RG, MacKenzie A, Tucci P. M3 Receptor Pathway Stimulates Rapid Transcription of the CB1 Receptor Activation through Calcium Signalling and the CNR1 Gene Promoter. Int J Mol Sci 2023; 24:ijms24021308. [PMID: 36674826 PMCID: PMC9867084 DOI: 10.3390/ijms24021308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/17/2022] [Accepted: 01/05/2023] [Indexed: 01/12/2023] Open
Abstract
In this study, we have investigated a possible mechanism that enables CB1/M3 receptor cross-talk, using SH-SY5Y cells as a model system. Our results show that M3 receptor activation initiates signaling that rapidly upregulates the CNR1 gene, resulting in a greatly potentiated CB1 receptor response to agonists. Calcium homeostasis plays an essential intermediary role in this functional CB1/M3 receptor cross-talk. We show that M3 receptor-triggered calcium release greatly increases CB1 receptor expression via both transcriptional and translational activity, by enhancing CNR1 promoter activity. The co-expression of M3 and CB1 receptors in brain areas such as the nucleus accumbens and amygdala support the hypothesis that the altered synaptic plasticity observed after exposure to cannabinoids involves cross-talk with the M3 receptor subtype. In this context, M3 receptors and their interaction with the cannabinoid system at the transcriptional level represent a potential pharmacogenomic target not only for the develop of new drugs for addressing addiction and tolerance. but also to understand the mechanisms underpinning response stratification to cannabinoids.
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Affiliation(s)
- Pietro Marini
- Institute of Education in Healthcare and Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Philip Cowie
- The Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Ahmet Ayar
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080 Trabzon, Turkey
| | - Guy S. Bewick
- The Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - John Barrow
- Institute of Education in Healthcare and Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Roger G. Pertwee
- The Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Alasdair MacKenzie
- The Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Paolo Tucci
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
- Correspondence:
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6
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Allen M, Huang BS, Notaras MJ, Lodhi A, Barrio-Alonso E, Lituma PJ, Wolujewicz P, Witztum J, Longo F, Chen M, Greening DW, Klann E, Ross ME, Liston C, Colak D. Astrocytes derived from ASD individuals alter behavior and destabilize neuronal activity through aberrant Ca 2+ signaling. Mol Psychiatry 2022; 27:2470-2484. [PMID: 35365802 PMCID: PMC9135629 DOI: 10.1038/s41380-022-01486-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/01/2022] [Accepted: 02/11/2022] [Indexed: 01/08/2023]
Abstract
The cellular mechanisms of autism spectrum disorder (ASD) are poorly understood. Cumulative evidence suggests that abnormal synapse function underlies many features of this disease. Astrocytes regulate several key neuronal processes, including the formation of synapses and the modulation of synaptic plasticity. Astrocyte abnormalities have also been identified in the postmortem brain tissue of ASD individuals. However, it remains unclear whether astrocyte pathology plays a mechanistic role in ASD, as opposed to a compensatory response. To address this, we combined stem cell culturing with transplantation techniques to determine disease-specific properties inherent to ASD astrocytes. We demonstrate that ASD astrocytes induce repetitive behavior as well as impair memory and long-term potentiation when transplanted into the healthy mouse brain. These in vivo phenotypes were accompanied by reduced neuronal network activity and spine density caused by ASD astrocytes in hippocampal neurons in vitro. Transplanted ASD astrocytes also exhibit exaggerated Ca2+ fluctuations in chimeric brains. Genetic modulation of evoked Ca2+ responses in ASD astrocytes modulates behavior and neuronal activity deficits. Thus, this study determines that astrocytes derived from ASD iPSCs are sufficient to induce repetitive behavior as well as cognitive deficit, suggesting a previously unrecognized primary role for astrocytes in ASD.
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Affiliation(s)
- Megan Allen
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Ben S Huang
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA.,Department of Psychiatry, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Michael J Notaras
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Aiman Lodhi
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Estibaliz Barrio-Alonso
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Pablo J Lituma
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Paul Wolujewicz
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Jonathan Witztum
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Francesco Longo
- Center for Neural Science, New York University, New York, NY, USA
| | - Maoshan Chen
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, VIC, Australia.,Baker Department of Cardiovascular Research, Translation and Implementation, La Trobe University, Melbourne, VIC, Australia.,Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - David W Greening
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, VIC, Australia.,Baker Department of Cardiovascular Research, Translation and Implementation, La Trobe University, Melbourne, VIC, Australia.,Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA
| | - M Elizabeth Ross
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Conor Liston
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA.,Department of Psychiatry, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Dilek Colak
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA. .,Gale and Ira Drukier Institute for Children's Health, Weill Cornell Medicine, Cornell University, New York, NY, USA.
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7
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Beeraka NM, Vikram PRH, Greeshma MV, Uthaiah CA, Huria T, Liu J, Kumar P, Nikolenko VN, Bulygin KV, Sinelnikov MY, Sukocheva O, Fan R. Recent Investigations on Neurotransmitters' Role in Acute White Matter Injury of Perinatal Glia and Pharmacotherapies-Glia Dynamics in Stem Cell Therapy. Mol Neurobiol 2022; 59:2009-2026. [PMID: 35041139 DOI: 10.1007/s12035-021-02700-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 12/10/2021] [Indexed: 02/05/2023]
Abstract
Periventricular leukomalacia (PVL) and cerebral palsy are two neurological disease conditions developed from the premyelinated white matter ischemic injury (WMI). The significant pathophysiology of these diseases is accompanied by the cognitive deficits due to the loss of function of glial cells and axons. White matter makes up 50% of the brain volume consisting of myelinated and non-myelinated axons, glia, blood vessels, optic nerves, and corpus callosum. Studies over the years have delineated the susceptibility of white matter towards ischemic injury especially during pregnancy (prenatal, perinatal) or immediately after child birth (postnatal). Impairment in membrane depolarization of neurons and glial cells by ischemia-invoked excitotoxicity is mediated through the overactivation of NMDA receptors or non-NMDA receptors by excessive glutamate influx, calcium, or ROS overload and has been some of the well-studied molecular mechanisms conducive to the injury of white matter. Expression of glutamate receptors (GluR) and transporters (GLT1, EACC1, and GST) has significant influence in glial and axonal-mediated injury of premyelinated white matter during PVL and cerebral palsy. Predominantly, the central premyelinated axons express extensive levels of functional NMDA GluR receptors to confer ischemic injury to premyelinated white matter which in turn invoke defects in neural plasticity. Several underlying molecular mechanisms are yet to be unraveled to delineate the complete pathophysiology of these prenatal neurological diseases for developing the novel therapeutic modalities to mitigate pathophysiology and premature mortality of newborn babies. In this review, we have substantially discussed the above multiple pathophysiological aspects of white matter injury along with glial dynamics, and the pharmacotherapies including recent insights into the application of MSCs as therapeutic modality in treating white matter injury.
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Affiliation(s)
- Narasimha M Beeraka
- Cancer Center, Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, People's Republic of China
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR), Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education and Research (JSS AHER), Mysuru, Karnataka, India
- Department of Human Anatomy, I. M. Sechenov First Moscow State Medical University (Sechenov University), St. Trubetskaya, 8, bld. 2, Moscow, 119991, Russia
| | - P R Hemanth Vikram
- Department of Pharmaceutical Chemistry, JSS Pharmacy College, Mysuru, Karnataka, India
| | - M V Greeshma
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR), Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education and Research (JSS AHER), Mysuru, Karnataka, India
| | - Chinnappa A Uthaiah
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR), Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education and Research (JSS AHER), Mysuru, Karnataka, India
| | - Tahani Huria
- Faculty of Medicine, Benghazi University, Benghazi, Libya
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, LE1 7RH, UK
| | - Junqi Liu
- Cancer Center, Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, People's Republic of China
| | - Pramod Kumar
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER-Guwahati), SilaKatamur (Halugurisuk), Changsari, Kamrup, 781101, Assam, India
| | - Vladimir N Nikolenko
- Department of Human Anatomy, I. M. Sechenov First Moscow State Medical University (Sechenov University), St. Trubetskaya, 8, bld. 2, Moscow, 119991, Russia
- Department of Normal and Topographic Anatomy, Faculty of Fundamental Medicine, Lomonosov Moscow State University, Moscow, Russia
| | - Kirill V Bulygin
- Department of Human Anatomy, I. M. Sechenov First Moscow State Medical University (Sechenov University), St. Trubetskaya, 8, bld. 2, Moscow, 119991, Russia
| | - Mikhail Y Sinelnikov
- Department of Human Anatomy, I. M. Sechenov First Moscow State Medical University (Sechenov University), St. Trubetskaya, 8, bld. 2, Moscow, 119991, Russia
- Research Institute of Human Morphology, 3 Tsyurupy Street, Moscow, 117418, Russian Federation
| | - Olga Sukocheva
- Discipline of Health Sciences, College of Nursing and Health Sciences, Flinders University, Bedford Park, South Australia, 5042, Australia
| | - Ruitai Fan
- Cancer Center, Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, People's Republic of China.
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8
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Peters A, Rabe P, Liebing AD, Krumbholz P, Nordström A, Jäger E, Kraft R, Stäubert C. Hydroxycarboxylic acid receptor 3 and GPR84 – Two metabolite-sensing G protein-coupled receptors with opposing functions in innate immune cells. Pharmacol Res 2022; 176:106047. [DOI: 10.1016/j.phrs.2021.106047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/21/2022]
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9
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Kheradpezhouh E, Tang MF, Mattingley JB, Arabzadeh E. Enhanced Sensory Coding in Mouse Vibrissal and Visual Cortex through TRPA1. Cell Rep 2021; 32:107935. [PMID: 32698003 DOI: 10.1016/j.celrep.2020.107935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/25/2020] [Accepted: 06/29/2020] [Indexed: 01/01/2023] Open
Abstract
Transient receptor potential ankyrin 1 (TRPA1) is a non-selective cation channel, broadly expressed throughout the body. Despite its expression in the mammalian brain, little is known about the contribution of TRPA1 to cortical function. Here, we characterize how TRPA1 affects sensory information processing in two cortical areas in mice: the primary vibrissal (whisker) somatosensory cortex (vS1) and the primary visual cortex (V1). In vS1, local activation of TRPA1 by allyl isothiocyanate (AITC) increases the ongoing activity of neurons and their evoked response to vibrissal stimulation, producing a positive gain modulation. The gain modulation is reversed by TRPA1 inhibitor HC-030031 and is absent in TRPA1 knockout mice. Similarly, in V1, TRPA1 activation increases the gain of direction and orientation selectivity. Linear decoding of V1 population activity confirms faster and more reliable encoding of visual signals under TRPA1 activation. Overall, our findings reveal a physiological role for TRPA1 in enhancing sensory signals in the mammalian cortex.
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Affiliation(s)
- Ehsan Kheradpezhouh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; The Australian Research Council Centre of Excellence for Integrative Brain Function, Australia.
| | - Matthew F Tang
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; The Australian Research Council Centre of Excellence for Integrative Brain Function, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Jason B Mattingley
- The Australian Research Council Centre of Excellence for Integrative Brain Function, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia; School of Psychology, The University of Queensland, Brisbane, QLD, Australia; Canadian Institute for Advanced Research (CIFAR), Toronto, ON, Canada
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia; The Australian Research Council Centre of Excellence for Integrative Brain Function, Australia
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10
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The PDZ motif peptide of ZO-1 attenuates Pseudomonas aeruginosa LPS-induced airway inflammation. Sci Rep 2020; 10:19644. [PMID: 33184397 PMCID: PMC7665049 DOI: 10.1038/s41598-020-76883-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/02/2020] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa is known to play a role in many human diseases. Therefore, examining the negative control mechanisms of tight junction protein ZO-1 on the exotoxin LPS of P. aeruginosa-induced diseases could be critical in the development of novel therapeutics. We found that ZO-1 expression dramatically decreased in inflammatory human lung tissues. Interestingly, PDZ1 deletion of the PDZ domain in the ZO-1 protein dramatically decreased LPS-induced F-actin formation and increased the expression of genes for pro-inflammatory cytokines, but not PDZ2 and PDZ3 of the ZO-1 protein. We also found that the consensus PDZ peptide (based on PDZ1) of ZO-1 down-regulates the expression of pro-inflammatory cytokine genes and F-actin formation; in contrast, the GG24,25AA mutant PDZ peptide cannot control these genes. LPS activates IL-8 secretion extracellularly in a time-dependent manner, while the secretion is inhibited by PDZ peptide. Whereas increased IL-8 secretion by LPS activates the CXCR2 receptor, overexpressed RGS12 negatively regulates LPS-induced CXCR2/IL-8 signaling. The PDZ peptide also decreases LPS-induced inflammatory cell populations, pro-inflammatory cytokine gene expression, and TEER in bronchoalveolar lavage fluid and cultured alveolar macrophages. Collectively, we suggest that the PDZ peptide may be a potential therapeutic for bacteria-induced respiratory diseases.
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11
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Lyons EL, Leone-Kabler S, Kovach AL, Thomas BF, Howlett AC. Cannabinoid receptor subtype influence on neuritogenesis in human SH-SY5Y cells. Mol Cell Neurosci 2020; 109:103566. [PMID: 33049367 DOI: 10.1016/j.mcn.2020.103566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/01/2020] [Accepted: 10/06/2020] [Indexed: 10/23/2022] Open
Abstract
Human SH-SY5Y neuroblastoma cells stably expressing exogenous CB1 (CB1XS) or CB2 (CB2XS) receptors were developed to investigate endocannabinoid signaling in the extension of neuronal projections. Expression of cannabinoid receptors did not alter proliferation rate, viability, or apoptosis relative to parental SH-SY5Y. Transcripts for endogenous cannabinoid system enzymes (diacylglycerol lipase, monoacylglycerol lipase, α/β-hydrolase domain containing proteins 6 and 12, N-acyl phosphatidylethanolamine-phospholipase D, and fatty acid amide hydrolase) were not altered by CB1 or CB2 expression. Endocannabinoid ligands 2-arachidonoylglycerol (2-AG) and anandamide were quantitated in SH-SY5Y cells, and diacylglycerol lipase inhibitor tetrahydrolipstatin decreased 2-AG abundance by 90% but did not alter anandamide abundance. M3 muscarinic agonist oxotremorine M, and inhibitors of monoacylglycerol lipase and α/β hydrolase domain containing proteins 6 &12 increased 2-AG abundance. CB1 receptor expression increased lengths of short (<30 μm) and long (>30 μm) projections, and this effect was significantly reduced by tetrahydrolipstatin, indicative of stimulation by endogenously produced 2-AG. Pertussis toxin, Gβγ inhibitor gallein, and β-arrestin inhibitor barbadin did not significantly alter long projection length in CB1XS, but significantly reduced short projections, with gallein having the greatest inhibition. The rho kinase inhibitor Y27632 increased CB1 receptor-mediated long projection extension, indicative of actin cytoskeleton involvement. CB1 receptor expression increased GAP43 and ST8SIA2 mRNA and decreased ITGA1 mRNA, whereas CB2 receptor expression increased NCAM and SYT mRNA. We propose that basal endogenous production of 2-AG provides autocrine stimulation of CB1 receptor signaling through Gi/o, Gβγ, and β-arrestin mechanisms to promote neuritogenesis, and rho kinase influences process extension.
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Affiliation(s)
- Erica L Lyons
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, One Medical Center Blvd., Winston-Salem, NC 27157, USA.
| | - Sandra Leone-Kabler
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, One Medical Center Blvd., Winston-Salem, NC 27157, USA.
| | - Alexander L Kovach
- Discovery Sciences, RTI International, PO Box 12194, Research Triangle Park, NC 27709, USA.
| | - Brian F Thomas
- Discovery Sciences, RTI International, PO Box 12194, Research Triangle Park, NC 27709, USA.
| | - Allyn C Howlett
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, One Medical Center Blvd., Winston-Salem, NC 27157, USA.
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12
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Gambardella J, Sorriento D, Bova M, Rusciano M, Loffredo S, Wang X, Petraroli A, Carucci L, Mormile I, Oliveti M, Bruno Morelli M, Fiordelisi A, Spadaro G, Campiglia P, Sala M, Trimarco B, Iaccarino G, Santulli G, Ciccarelli M. Role of Endothelial G Protein-Coupled Receptor Kinase 2 in Angioedema. Hypertension 2020; 76:1625-1636. [PMID: 32895019 DOI: 10.1161/hypertensionaha.120.15130] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Excessive BK (bradykinin) stimulation is responsible for the exaggerated permeabilization of the endothelium in angioedema. However, the molecular mechanisms underlying these responses have not been investigated. BK receptors are Gq-protein-coupled receptors phosphorylated by GRK2 (G protein-coupled receptor kinase 2) with a hitherto unknown biological and pathophysiological significance. In the present study, we sought to identify the functional role of GRK2 in angioedema through the regulation of BK signaling. We found that the accumulation of cytosolic Ca2+ in endothelial cells induced by BK was sensitive to GRK2 activity, as it was significantly augmented by inhibiting the kinase. Accordingly, permeabilization and NO production induced by BK were enhanced, as well. In vivo, mice with reduced GRK2 levels in the endothelium (Tie2-CRE/GRK2fl+/fl-) exhibited an increased response to BK in terms of vascular permeability and extravasation. Finally, patients with reduced GRK2 levels displayed a severe phenotype of angioedema. Taken together, these findings establish GRK2 as a novel pivotal regulator of BK signaling with an essential role in the pathophysiology of vascular permeability and angioedema.
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Affiliation(s)
- Jessica Gambardella
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy.,Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,International Translational Research and Medical Education Consortium (ITME), NA, Italy (J.G., B.T., G. Santulli)
| | - Daniela Sorriento
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Maria Bova
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Mariarosaria Rusciano
- Montevergine Hospital, Mercogliano, Italy (M.R.).,Department of Medicine and Surgery (M.R., M.O., M.C.), University of Salerno, Italy
| | - Stefania Loffredo
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Xujun Wang
- Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY
| | - Angelica Petraroli
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Laura Carucci
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Ilaria Mormile
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Marco Oliveti
- Department of Medicine and Surgery (M.R., M.O., M.C.), University of Salerno, Italy
| | - Marco Bruno Morelli
- Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY
| | - Antonella Fiordelisi
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy
| | - Giuseppe Spadaro
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Pietro Campiglia
- Division of Biomedicine, Department of Pharmaceutical Science (P.C., M.S.), University of Salerno, Italy
| | - Marina Sala
- Division of Biomedicine, Department of Pharmaceutical Science (P.C., M.S.), University of Salerno, Italy
| | - Bruno Trimarco
- International Translational Research and Medical Education Consortium (ITME), NA, Italy (J.G., B.T., G. Santulli)
| | - Guido Iaccarino
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy
| | - Gaetano Santulli
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy.,Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,International Translational Research and Medical Education Consortium (ITME), NA, Italy (J.G., B.T., G. Santulli)
| | - Michele Ciccarelli
- Department of Medicine and Surgery (M.R., M.O., M.C.), University of Salerno, Italy
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13
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Zhuge Y, Zhang J, Qian F, Wen Z, Niu C, Xu K, Ji H, Rong X, Chu M, Jia C. Role of smooth muscle cells in Cardiovascular Disease. Int J Biol Sci 2020; 16:2741-2751. [PMID: 33110393 PMCID: PMC7586427 DOI: 10.7150/ijbs.49871] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022] Open
Abstract
Normally, smooth muscle cells (SMCs) are localized in the tunica media of the vasculature, where they take responsibility for vascular contraction and extracellular matrix (ECM) generation. SMCs also play a significant role in obedience and elastic rebound of the artery in response to the haemodynamic condition. However, under pathological or stressed conditions, phenotype switching from contractile to synthetic state or other cell types will occur in SMCs to positively or negatively contribute to disease progression. Various studies demonstrated that functional changes of SMCs are implicated in several cardiovascular diseases. In this review, we present the function of vascular SMCs (VSMCs) and the involved molecular mechanisms about phenotype switching, and summarize the roles of SMCs in atherosclerosis, hypertension, arterial aneurysms and myocardial infarction, hoping to obtain potential therapeutic targets against cardiovascular disease in the clinical practices.
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Affiliation(s)
- Yingzhi Zhuge
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China.,Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Jian Zhang
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China.,Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Fanyu Qian
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China.,Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Zhengwang Wen
- Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Chao Niu
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China.,Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Ke Xu
- The Institute of Life Sciences, Wenzhou University, Wenzhou, Zhejiang, China
| | - Hao Ji
- The Institute of Life Sciences, Wenzhou University, Wenzhou, Zhejiang, China
| | - Xing Rong
- Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Maoping Chu
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China.,Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Chang Jia
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China.,Children's Heart Center, Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
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14
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Menshchikov P, Ivantsova A, Manzhurtsev A, Ublinskiy M, Yakovlev A, Melnikov I, Kupriyanov D, Akhadov T, Semenova N. Separate N-acetyl aspartyl glutamate, N-acetyl aspartate, aspartate, and glutamate quantification after pediatric mild traumatic brain injury in the acute phase. Magn Reson Med 2020; 84:2918-2931. [PMID: 32544309 DOI: 10.1002/mrm.28332] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/27/2020] [Accepted: 05/01/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE To separately measure N-acetyl aspartul glutamate (NAAG), N-acetyl aspartate (NAA), aspartate (Asp), and glutamate (Glu) concentrations in white matter (WM) using J-editing techniques in patients with mild traumatic brain injury (mTBI) in the acute phase. METHODS Twenty-four patients with closed concussive head injury and 29 healthy volunteers were enrolled in the current study. For extended 1 H MRS examination, patients and controls were equally divided into two subgroups. In subgroup 1 (12 patients/15 controls), NAAG and NAA concentrations were measured in WM separately with MEGA-PRESS (echo time/repetition time [TE/TR] = 140/2000 ms; δ ON NAA / δ OFF NAA = 4.84/4.38 ppm, δ ON NAAG / δ OFF NAAG = 4.61/4.15 ppm). In subgroup 2 (12 patients/14 controls), Asp and Glu concentrations were acquired with MEGA-PRESS (TE/TR = 90/2000 ms; δ ON Asp / δ OFF Asp = 3.89/5.21 ppm) and TE-averaged PRESS (TE from 35 ms to 185 ms with 2.5-ms increments; TR = 2000 ms) pulse sequences, respectively. RESULTS tNAA and NAAG concentrations were found to be reduced, while NAA concentrations were unchanged, after mild mTBI. Reduced Asp and elevated myo-inositol (mI) concentrations were also found. CONCLUSION The main finding of the study is that the tNAA signal reduction in WM after mTBI is associated with a decrease in the NAAG concentration rather than a decrease in the NAA concentration, as was thought previously. This finding highlights the importance of separating these signals, at least for WM studies, to avoid misinterpretation of the results. NAAG plays an important role in selectively activating mGluR3 receptors, thus providing neuroprotective and neuroreparative functions immediately after mTBI. NAAG shows potential for the development of new therapeutic strategies for patients with injuries of varying severity.
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Affiliation(s)
- Petr Menshchikov
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | - Anna Ivantsova
- Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | - Andrei Manzhurtsev
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | - Maxim Ublinskiy
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | - Alexey Yakovlev
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | - Ilya Melnikov
- Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | | | - Tolib Akhadov
- Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
| | - Natalia Semenova
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation.,Clinical and Research Institute of Emergency Paediatric Surgery and Traumatology, Moscow, Russian Federation
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15
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Dziedzic A, Miller E, Saluk-Bijak J, Bijak M. The GPR17 Receptor-A Promising Goal for Therapy and a Potential Marker of the Neurodegenerative Process in Multiple Sclerosis. Int J Mol Sci 2020; 21:ijms21051852. [PMID: 32182666 PMCID: PMC7084627 DOI: 10.3390/ijms21051852] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 02/29/2020] [Accepted: 03/06/2020] [Indexed: 12/28/2022] Open
Abstract
One of the most important goals in the treatment of demyelinating diseases such as multiple sclerosis (MS) is, in addition to immunomodulation, reconstruction of the lost myelin sheath. The modulator of the central nervous system myelination is the metabotropic receptor coupled to the G-protein: GPR17. GPR17 receptors are considered to be sensors of local damage to the myelin sheath, and play a role in the reconstruction and repair of demyelinating plaques caused by ongoing inflammatory processes. GPR17 receptors are present on nerve cells and precursor oligodendrocyte cells. Under physiological conditions, they are responsible for the differentiation and subsequent maturation of oligodendrocytes, while under pathological conditions (during damage to nerve cells), their expression increases to become mediators in the demyelinating processes. Moreover, they are essential not only in both the processes of inducing damage and the death of neurons, but also in the local repair of the damaged myelin sheath. Therefore, GPR17 receptors may be recognized as the potential goal in creating innovative therapies for the treatment of the neurodegenerative process in MS, based on the acceleration of the remyelination processes. This review examines the role of GRP17 in pathomechanisms of MS development.
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Affiliation(s)
- Angela Dziedzic
- Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; (A.D.); (J.S.-B.)
| | - Elzbieta Miller
- Department of Neurological Rehabilitation, Medical University of Lodz, Milionowa 14, 93-113 Lodz, Poland;
| | - Joanna Saluk-Bijak
- Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; (A.D.); (J.S.-B.)
| | - Michal Bijak
- Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
- Correspondence: ; Tel.: +48-42-635-4336
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16
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Chemogenetic Activation of Excitatory Neurons Alters Hippocampal Neurotransmission in a Dose-Dependent Manner. eNeuro 2019; 6:ENEURO.0124-19.2019. [PMID: 31645362 PMCID: PMC6860986 DOI: 10.1523/eneuro.0124-19.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/26/2019] [Accepted: 09/30/2019] [Indexed: 11/21/2022] Open
Abstract
Designer receptors exclusively activated by designer drugs (DREADD)-based chemogenetic tools are extensively used to manipulate neuronal activity in a cell type-specific manner. Whole-cell patch-clamp recordings indicate membrane depolarization, coupled with increased neuronal firing rate, following administration of the DREADD ligand, clozapine-N-oxide (CNO) to activate the Gq-coupled DREADD, hM3Dq. Although hM3Dq has been used to enhance neuronal firing in order to manipulate diverse behaviors, often within 30 min to 1 h after CNO administration, the physiological effects on excitatory neurotransmission remain poorly understood. We investigated the influence of CNO-mediated hM3Dq DREADD activation on distinct aspects of hippocampal excitatory neurotransmission at the Schaffer collateral-CA1 synapse in hippocampal slices derived from mice expressing hM3Dq in Ca2+/calmodulin-dependent protein kinase α (CamKIIα)-positive excitatory neurons. Our results indicate a clear dose-dependent effect on field EPSP (fEPSP) slope, with no change noted at the lower dose of CNO (1 µM) and a significant, long-term decline in fEPSP slope observed at higher doses (5-20 µM). Further, we noted a robust θ burst stimulus (TBS) induced long-term potentiation (LTP) in the presence of the lower CNO (1 µM) dose, which was significantly attenuated at the higher CNO (20 µM) dose. Whole-cell patch-clamp recording revealed both complex dose-dependent regulation of excitability, and spontaneous and evoked activity of CA1 pyramidal neurons in response to hM3Dq activation across CNO concentrations. Our data indicate that CNO-mediated activation of the hM3Dq DREADD results in dose-dependent regulation of excitatory hippocampal neurotransmission and highlight the importance of careful interpretation of behavioral experiments involving chemogenetic manipulation.
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17
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Synthetic GPCRs and signal transduction cascades. Emerg Top Life Sci 2019; 3:609-614. [PMID: 33523176 DOI: 10.1042/etls20190035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 12/20/2022]
Abstract
G protein-coupled receptors (GPCRs) are a large and diverse group of membrane proteins that constitute over 30% of FDA approved drug targets. Despite their importance, much remains unknown about GPCR signaling at a system's level. Efforts to engineer receptors with orthogonal components have attempted to provide tools to parse signaling and resultant phenotypes. Recent advances in synthetic biology provide opportunities to engineer receptors at scale and with additional properties that could further inform GPCR biology at a system's level, and enhance the ability to engineer complex signal transduction.
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18
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Li S, Zhang D, Lu K, Wu Y, Sheng L, Tang Q. Activation of calcium signaling in human gingival fibroblasts by recombinant Porphyromonas gingivalis RgpB protein. Eur J Oral Sci 2019; 127:287-293. [PMID: 31175838 DOI: 10.1111/eos.12622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2019] [Indexed: 11/28/2022]
Abstract
Arginine-specific cysteine proteinases, such as Arg-gingipain B (RgpB), mediate inflammation by activating protease-activated receptors (PARs). Arg-gingipain B is produced by Porphyromonas gingivalis, and is implicated in the causation of periodontal disease. The purpose of the present study was to observe the influence of recombinant RgpB protein (rRgpB) on PAR activation by monitoring intracellular Ca2+ ion concentration ([Ca2+]i) and inositol-1,4,5-triphosphate (IP3) levels in human gingival fibroblasts (HGFs). Our findings showed that rRgpB could cause a transient increase in [Ca2+]i. This increase in [Ca2+]i was completely suppressed by vorapaxar, a PAR-1 antagonist. Recombinant Arg-gingipain B increased the concentration of IP3, reaching a maximum at 60 s after treatment; this was completely inhibited by vorapaxar. We therefore conclude that rRgpB-induced calcium signaling in HGFs is mainly caused by PAR-1 activation. This suggests that PAR-1 activation plays a significant role in chronic inflammatory periodontal disease induced by P. gingivalis RgpB.
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Affiliation(s)
- Shenglai Li
- Department of Oral and Maxillofacial Surgery, Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Diya Zhang
- Dental Department, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Kexin Lu
- Department of Oral Medicine, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yanmin Wu
- Department of Oral Medicine, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lieping Sheng
- Dental Department, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qi Tang
- Department of Oral Medicine, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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19
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Optical approaches for single-cell and subcellular analysis of GPCR-G protein signaling. Anal Bioanal Chem 2019; 411:4481-4508. [PMID: 30927013 DOI: 10.1007/s00216-019-01774-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 01/05/2023]
Abstract
G protein-coupled receptors (GPCRs), G proteins, and their signaling associates are major signal transducers that control the majority of cellular signaling and regulate key biological functions including immune, neurological, cardiovascular, and metabolic processes. These pathways are targeted by over one-third of drugs on the market; however, the current understanding of their function is limited and primarily derived from cell-destructive approaches providing an ensemble of static, multi-cell information about the status and composition of molecules. Spatiotemporal behavior of molecules involved is crucial to understanding in vivo cell behaviors both in health and disease, and the advent of genetically encoded fluorescence proteins and small fluorophore-based biosensors has facilitated the mapping of dynamic signaling in cells with subcellular acuity. Since we and others have developed optogenetic methods to regulate GPCR-G protein signaling in single cells and subcellular regions using dedicated wavelengths, the desire to develop and adopt optogenetically amenable assays to measure signaling has motivated us to take a broader look at the available optical tools and approaches compatible with measuring single-cell and subcellular GPCR-G protein signaling. Here we review such key optical approaches enabling the examination of GPCR, G protein, secondary messenger, and downstream molecules such as kinase and lipid signaling in living cells. The methods reviewed employ both fluorescence and bioluminescence detection. We not only further elaborate the underlying principles of these sensors but also discuss the experimental criteria and limitations to be considered during their use in single-cell and subcellular signal mapping.
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20
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Kankanamge D, Tennakoon M, Weerasinghe A, Cedeno-Rosario L, Chadee DN, Karunarathne A. G protein αq exerts expression level-dependent distinct signaling paradigms. Cell Signal 2019; 58:34-43. [PMID: 30849518 DOI: 10.1016/j.cellsig.2019.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/23/2019] [Accepted: 02/25/2019] [Indexed: 12/16/2022]
Abstract
G protein αq-coupled receptors (Gq-GPCRs) primarily signal through GαqGTP mediated phospholipase Cβ (PLCβ) stimulation and the subsequent hydrolysis of phosphatidylinositol 4, 5 bisphosphate (PIP2). Though Gq-heterotrimer activation results in both GαqGTP and Gβγ, unlike Gi/o-receptors, it is unclear if Gq-coupled receptors employ Gβγ as a major signal transducer. Compared to Gi/o- and Gs-coupled receptors, we observed that most cell types exhibit a limited free Gβγ generation upon Gq-pathway and Gαq/11 heterotrimer activation. We show that cells transfected with Gαq or endogenously expressing more than average-levels of Gαq/11 compared to Gαs and Gαi exhibit a distinct signaling regime primarily characterized by recovery-resistant PIP2 hydrolysis. Interestingly, the elevated Gq-expression is also associated with enhanced free Gβγ generation and signaling. Furthermore, the gene GNAQ, which encodes for Gαq, has recently been identified as a cancer driver gene. We also show that GNAQ is overexpressed in tumor samples of patients with Kidney Chromophobe (KICH) and Kidney renal papillary (KIRP) cell carcinomas in a matched tumor-normal sample analysis, which demonstrates the clinical significance of Gαq expression. Overall, our data indicates that cells usually express low Gαq levels, likely safeguarding cells from excessive calcium as wells as from Gβγ signaling.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Amila Weerasinghe
- McDonnell Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA
| | - Luis Cedeno-Rosario
- Department of Biological Sciences, The University of Toledo, Toledo, OH 43606, USA
| | - Deborah N Chadee
- Department of Biological Sciences, The University of Toledo, Toledo, OH 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA.
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Abiero A, Botanas CJ, Sayson LV, Custodio RJ, de la Peña JB, Kim M, Lee HJ, Seo JW, Ryu IS, Chang CM, Yang JS, Lee YS, Jang CG, Kim HJ, Cheong JH. 5-Methoxy-α-methyltryptamine (5-MeO-AMT), a tryptamine derivative, induces head-twitch responses in mice through the activation of serotonin receptor 2a in the prefrontal cortex. Behav Brain Res 2019; 359:828-835. [DOI: 10.1016/j.bbr.2018.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/10/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022]
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Verma AK, Ghosh S, Basu A. Chandipura Virus Induced Neuronal Apoptosis via Calcium Signaling Mediated Oxidative Stress. Front Microbiol 2018; 9:1489. [PMID: 30034380 PMCID: PMC6043780 DOI: 10.3389/fmicb.2018.01489] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/15/2018] [Indexed: 01/06/2023] Open
Abstract
Chandipura Virus (CHPV) a negative-stranded RNA virus belonging to the Rhabdoviridae family, has been previously reported to bring about neuronal apoptosis by stimulating oxidative stress. Our in silico data suggested the involvement of Angiotensin II in intracellular Ca2+ secretion within CHPV infected cells that further lead to enhancement of ROS level and mitochondrial dysfunction. ROS is also known to phosphorylate p38 that leads to neuronal apoptosis through FasL-FADD pathway during CHPV infection. Minocycline a broad-spectrum antibiotic well-known for its anti-oxidative and anti-inflammatory role was used in the present study to investigate its efficacy against CHPV. The results obtained from the present study showed minocycline to be effective in mitigating the levels of cytoplasmic Ca2+, ROS, phosphorylation of p38 molecules and hence cellular apoptosis. Thus minocycline apart from being an anti-inflammatory and anti-oxidative agent, our study showed that minocycline has an additional Ca2+ chelation activity.
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Patel J, Chuaiphichai S, Douglas G, Gorvin CM, Channon KM. Vascular wall regulator of G-protein signalling-1 (RGS-1) is required for angiotensin II-mediated blood pressure control. Vascul Pharmacol 2018; 108:15-22. [PMID: 29654907 PMCID: PMC6073721 DOI: 10.1016/j.vph.2018.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 03/18/2018] [Accepted: 04/05/2018] [Indexed: 02/07/2023]
Abstract
G-Protein coupled receptors (GPCRs) activate intracellular signalling pathways by coupling to heterotrimeric G-proteins that control many physiological processes including blood pressure homeostasis. The Regulator of G-Protein Signalling-1 (RGS1) controls the magnitude and duration of downstream GPCR signalling by acting as a GTPase-activating protein for specific Gα-proteins. RGS1 has contrasting roles in haematopoietic and non-haematopoietic cells. Rgs1−/−ApoE−/− mice are protected from Angiotensin II (Ang II)-induced aortic aneurysm rupture. Conversely, Ang II treatment increases systolic blood pressure to a greater extent in Rgs1−/−ApoE−/− mice than ApoE−/− mice, independent of its role in myeloid cells. However the precise role of RGS1 in hypertension and vascular-derived cells remains unknown. We determined the effects of Rgs1 deletion on vascular function in ApoE−/− mice. Rgs1 deletion led to enhanced vasoconstriction in aortas and mesenteric arteries from ApoE−/− mice in response to phenylephrine (PE) and U46619 respectively. Rgs1 was shown to have a role in the vasculature, with endothelium-dependent vasodilation being impaired, and endothelium-independent dilatation to SNP being enhanced in Rgs1−/−ApoE−/− mesenteric arteries. To address the downstream signalling pathways in vascular smooth muscle cells (VSMCs) in response to Ang II-stimulation, we assessed pErk1/2, pJNK and pp38 MAPK activation in VSMCs transiently transfected with Rgs1. pErk1/2 signalling but not pJNK and pp38 signalling was impaired in the presence of Rgs1. Furthermore, we demonstrated that the enhanced contractile response to PE in Rgs1−/−ApoE−/− aortas was reduced by a MAPK/Erk (MEK) inhibitor and an L-type voltage gated calcium channel antagonist, suggesting that Erk1/2 signalling and calcium influx are major effectors of Rgs1-mediated vascular contractile responses, respectively. These findings indicate RGS1 is a novel regulator of blood pressure homeostasis and highlight RGS1-controlled signalling pathways in the vasculature that may be new drug development targets for hypertension.
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MESH Headings
- Angiotensin II
- Animals
- Aorta, Thoracic/metabolism
- Aorta, Thoracic/physiopathology
- Blood Pressure/genetics
- Calcium Signaling
- Cell Line
- Disease Models, Animal
- Hypertension/chemically induced
- Hypertension/genetics
- Hypertension/metabolism
- Hypertension/physiopathology
- Male
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/physiopathology
- Mice, Knockout, ApoE
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Phosphorylation
- RGS Proteins/deficiency
- RGS Proteins/genetics
- RGS Proteins/metabolism
- Receptor, Angiotensin, Type 1/metabolism
- Vasoconstriction
- Vasodilation
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Affiliation(s)
- Jyoti Patel
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
| | - Surawee Chuaiphichai
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Gillian Douglas
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Caroline M Gorvin
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology, and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK
| | - Keith M Channon
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
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Depolarizing, inhibitory GABA type A receptor activity regulates GABAergic synapse plasticity via ERK and BDNF signaling. Neuropharmacology 2017; 128:324-339. [PMID: 29074304 DOI: 10.1016/j.neuropharm.2017.10.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 10/02/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022]
Abstract
γ-aminobutyric acid (GABA) begins as the key excitatory neurotransmitter in newly forming circuits, with chloride efflux from GABA type A receptors (GABAARs) producing membrane depolarization, which promotes calcium entry, dendritic outgrowth and synaptogenesis. As development proceeds, GABAergic signaling switches to inhibitory hyperpolarizing neurotransmission. Despite the evidence of impaired GABAergic neurotransmission in neurodevelopmental disorders, little is understood on how agonist-dependent GABAAR activation controls the formation and plasticity of GABAergic synapses. We have identified a weakly depolarizing and inhibitory GABAAR response in cortical neurons that occurs during the transition period from GABAAR depolarizing excitation to hyperpolarizing inhibitory activity. We show here that treatment with the GABAAR agonist muscimol mediates structural changes that diminish GABAergic synapse strength through postsynaptic and presynaptic plasticity via intracellular Ca2+ stores, ERK and BDNF/TrkB signaling. Muscimol decreases synaptic localization of surface γ2 GABAARs and gephyrin postsynaptic scaffold while β2/3 non-γ2 GABAARs accumulate in the synapse. Concurrent with this structural plasticity, muscimol treatment decreases synaptic currents while enhancing the γ2 containing benzodiazepine sensitive GABAAR tonic current in an ERK dependent manner. We further demonstrate that GABAAR activation leads to a decrease in presynaptic GAD65 levels via BDNF/TrkB signaling. Together these data reveal a novel mechanism for agonist induced GABAergic synapse plasticity that can occur on the timescale of minutes, contributing to rapid modification of synaptic and circuit function.
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25
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An Essential Role of Fyn in the Modulation of Metabotropic Glutamate Receptor 1 in Neurons. eNeuro 2017; 4:eN-NWR-0096-17. [PMID: 28948209 PMCID: PMC5608834 DOI: 10.1523/eneuro.0096-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/08/2017] [Accepted: 08/15/2017] [Indexed: 11/26/2022] Open
Abstract
Fyn is a member of the Src family of nonreceptor tyrosine kinases and is broadly expressed in the CNS. As a synapse-enriched kinase, Fyn interacts with and phosphorylates local substrates to regulate synaptic transmission and plasticity, although our knowledge of specific targets of Fyn at synaptic sites remains incomplete and the accurate role of Fyn in regulating synaptic proteins is poorly understood. In this study, we initiated an effort to explore the interaction of Fyn with a metabotropic glutamate receptor (mGluR). We found that recombinant Fyn directly binds to mGluR1a at a consensus binding motif located in the intracellular C-terminus (CT) of mGluR1a in vitro. Similarly, endogenous Fyn interacts with mGluR1a in adult rat cerebellar neurons in vivo. Active Fyn phosphorylates mGluR1a at a conserved tyrosine residue in the CT region. In cerebellar neurons and transfected HEK293T cells, the Fyn-mediated tyrosine phosphorylation of mGluR1a is constitutively active and acts to facilitate the surface expression of mGluR1a and to potentiate the mGluR1a postreceptor signaling. These results support mGluR1a to be a novel substrate of Fyn. Fyn, by binding to and phosphorylating mGluR1a, potentiates surface expression and signaling of the receptors.
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26
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De Min A, Matera C, Bock A, Holze J, Kloeckner J, Muth M, Traenkle C, De Amici M, Kenakin T, Holzgrabe U, Dallanoce C, Kostenis E, Mohr K, Schrage R. A New Molecular Mechanism To Engineer Protean Agonism at a G Protein–Coupled Receptor. Mol Pharmacol 2017; 91:348-356. [DOI: 10.1124/mol.116.107276] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/02/2017] [Indexed: 12/22/2022] Open
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Rinne A, Mobarec JC, Mahaut-Smith M, Kolb P, Bünemann M. The mode of agonist binding to a G protein-coupled receptor switches the effect that voltage changes have on signaling. Sci Signal 2015; 8:ra110. [PMID: 26535008 DOI: 10.1126/scisignal.aac7419] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Signaling by many heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) is either enhanced or attenuated by changes in plasma membrane potential. To identify structural correlates of the voltage sensitivity of GPCR signaling, we chose muscarinic acetylcholine receptors (the M1, M3, and M5 isoforms) as a model system. We combined molecular docking analysis with Förster resonance energy transfer (FRET)-based assays that monitored receptor activity under voltage clamp conditions. When human embryonic kidney (HEK) 293 cells expressing the individual receptors were stimulated with the agonist carbachol, membrane depolarization enhanced signaling by the M1 receptor but attenuated signaling by the M3 and M5 receptors. Furthermore, whether membrane depolarization enhanced or inhibited receptor signaling depended on the type of agonist. Membrane depolarization attenuated M3 receptor signaling when the receptor was bound to carbachol or acetylcholine, whereas depolarization enhanced signaling when the receptor was bound to either choline or pilocarpine. Docking calculations predicted that there were two distinct binding modes for these ligands, which were associated with the effect of depolarization on receptor function. From these calculations, we identified a residue in the M3 receptor that, when mutated, would alter the binding mode of carbachol to resemble that of pilocarpine in silico. Introduction of this mutated M3 receptor into cells confirmed that the membrane depolarization enhanced, rather than attenuated, signaling by the carbachol-bound receptor. Together, these data suggest that the directionality of the voltage sensitivity of GPCR signaling is defined by the specific binding mode of each ligand to the receptor.
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Affiliation(s)
- Andreas Rinne
- Department of Cardiovascular Physiology, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Juan Carlos Mobarec
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, D-35032 Marburg, Germany
| | - Martyn Mahaut-Smith
- Department of Cell Physiology and Pharmacology, University of Leicester, University Road, P. O. Box 138, Leicester LE1 9HN, UK
| | - Peter Kolb
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, D-35032 Marburg, Germany
| | - Moritz Bünemann
- Department of Pharmacology and Clinical Pharmacy, Philipps University Marburg, Karl-von-Frisch-Str. 1, D-35043 Marburg, Germany.
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28
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Ichikawa J, Inoue R. TRPC6 regulates cell cycle progression by modulating membrane potential in bone marrow stromal cells. Br J Pharmacol 2015; 171:5280-94. [PMID: 25041367 DOI: 10.1111/bph.12840] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Ca(2+) influx is important for cell cycle progression, but the mechanisms involved seem to vary. We investigated the potential roles of transient receptor potential (TRP) channels and store-operated Ca(2+) entry (SOCE)-related molecules STIM (stromal interaction molecule)/Orai in the cell cycle progression of rat bone marrow stromal cells (BMSCs), a reliable therapeutic resource for regenerative medicine. EXPERIMENTAL APPROACH PCR and immunoblot analyses were used to examine mRNA and protein levels, fluorescence imaging and patch clamping for Ca(2+) influx and membrane potential measurements, and flow cytometry for cell cycle analysis. KEY RESULTS Cell cycle synchronization of BMSCs revealed S phase-specific enhancement of TRPC1, STIM and Orai mRNA and protein expression. In contrast, TRPC6 expression decreased in the S phase and increased in the G1 phase. Resting membrane potential (RMP) of BMSCs was most negative and positive in the S and G1 phases, respectively, and was accompanied by an enhancement and attenuation of SOCE respectively. Chemically depolarizing/hyperpolarizing the membrane erased these differences in SOCE magnitude during the cell cycle. siRNA knockdown of TRPC6 produced a negative shift in RMP, increased SOCE and caused redistribution of BMSCs with increased populations in the S and G2 /M phases and accumulation of cyclins A2 and B1. A low concentration of Gd(3+) (1 μM) suppressed BMSC proliferation at its concentration to inhibit SOC channels relatively specifically. CONCLUSIONS AND IMPLICATIONS TRPC6, by changing the membrane potential, plays a pivotal role in controlling the SOCE magnitude, which is critical for cell cycle progression of BMSCs. This finding provides a new therapeutic strategy for regulating BMSC proliferation.
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Affiliation(s)
- Jun Ichikawa
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
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29
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Seifert S, Sontheimer H. Bradykinin enhances invasion of malignant glioma into the brain parenchyma by inducing cells to undergo amoeboid migration. J Physiol 2014; 592:5109-27. [PMID: 25194042 DOI: 10.1113/jphysiol.2014.274498] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The molecular and cellular mechanisms governing cell motility and directed migration in response to the neuropeptide bradykinin are largely unknown. Here, we demonstrate that human glioma cells whose migration is guided by bradykinin generate bleb-like protrusions. We found that activation of the B2 receptor leads to a rise in free Ca(2+) from internal stores that activates actomyosin contraction and subsequent cytoplasmic flow into protrusions forming membrane blebs. Furthermore Ca(2+) activates Ca(2+)-dependent K(+) and Cl(-) channels, which participate in bleb regulation. Treatment of gliomas with bradykinin in situ increased glioma growth by increasing the speed of cell migration at the periphery of the tumour mass. To test if bleb formation is related to bradykinin-promoted glioma invasion we blocked glioma migration with blebbistatin, a blocker of myosin kinase II, which is necessary for proper bleb retraction. Our findings suggest a pivotal role of bradykinin during glioma invasion by stimulating amoeboid migration of glioma cells.
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Affiliation(s)
- Stefanie Seifert
- Department of Neurobiology and Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Harald Sontheimer
- Department of Neurobiology and Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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30
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Central genomic regulation of the expression of oestrous behaviour in dairy cows: a review. Animal 2014; 8:754-64. [PMID: 24598582 DOI: 10.1017/s1751731114000342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The expression of oestrous behaviour in Holstein Friesian dairy cows has progressively decreased over the past 50 years. Reduced oestrus expression is one of the factors contributing to the current suboptimal reproductive efficiency in dairy farming. Variation between and within cows in the expression of oestrous behaviour is associated with variation in peripheral blood oestradiol concentrations during oestrus. In addition, there is evidence for a priming role of progesterone for the full display of oestrous behaviour. A higher rate of metabolic clearance of ovarian steroids could be one of the factors leading to lower peripheral blood concentrations of oestradiol and progesterone in high-producing dairy cows. Oestradiol acts on the brain by genomic, non-genomic and growth factor-dependent mechanisms. A firm base of understanding of the ovarian steroid-driven central genomic regulation of female sexual behaviour has been obtained from studies on rodents. These studies have resulted in the definition of five modules of oestradiol-activated genes in the brain, referred to as the GAPPS modules. In a recent series of studies, gene expression in the anterior pituitary and four brain areas (amygdala, hippocampus, dorsal hypothalamus and ventral hypothalamus) in oestrous and luteal phase cows, respectively, has been measured, and the relation with oestrous behaviour of these cows was analysed. These studies identified a number of genes of which the expression was associated with the intensity of oestrous behaviour. These genes could be grouped according to the GAPPS modules, suggesting close similarity of the regulation of oestrous behaviour in cows and female sexual behaviour in rodents. A better understanding of the central genomic regulation of the expression of oestrous behaviour in dairy cows may in due time contribute to improved (genomic) selection strategies for appropriate oestrus expression in high-producing dairy cows.
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31
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Tukey DS, Ziff EB. Ca2+-permeable AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors and dopamine D1 receptors regulate GluA1 trafficking in striatal neurons. J Biol Chem 2013; 288:35297-306. [PMID: 24133208 DOI: 10.1074/jbc.m113.516690] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of striatal medium spiny neuron synapses underlies forms of motivated behavior and pathological drug seeking. A primary mechanism for increasing synaptic strength is the trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) into the postsynapse, a process mediated by GluA1 AMPAR subunit phosphorylation. We have examined the role of converging glutamate and dopamine inputs in regulating biochemical cascades upstream of GluA1 phosphorylation. We focused on the role of Ca(2+)-permeable AMPARs (CPARs), which lack the GluA2 AMPAR subunit. Under conditions that prevented depolarization, stimulation of CPARs activated neuronal nitric oxide synthase and production of cGMP. CPAR-dependent cGMP production was sufficient to induce synaptic insertion of GluA1, detected by confocal microscopy, through a mechanism dependent on GluA1 Ser-845 phosphorylation. Dopamine D1 receptors, in contrast, stimulate GluA1 extra synaptic insertion. Simultaneous activation of dopamine D1 receptors and CPARs induced additive increases in GluA1 membrane insertion, but only CPAR stimulation augmented CPAR-dependent GluA1 synaptic insertion. This incorporation into the synapse proceeded through a sequential two-step mechanism; that is, cGMP-dependent protein kinase II facilitated membrane insertion and/or retention, and protein kinase C activity was necessary for synaptic insertion. These data suggest a feed-forward mechanism for synaptic priming whereby an initial stimulus acting independently of voltage-gated conductance increases striatal neuron excitability, facilitating greater neuronal excitation by a subsequent stimulus.
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Affiliation(s)
- David S Tukey
- From the Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016
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32
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Norton CE, Broughton BRS, Jernigan NL, Walker BR, Resta TC. Enhanced depolarization-induced pulmonary vasoconstriction following chronic hypoxia requires EGFR-dependent activation of NAD(P)H oxidase 2. Antioxid Redox Signal 2013; 18:1777-88. [PMID: 22966991 PMCID: PMC3619151 DOI: 10.1089/ars.2012.4836] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AIMS Chronic hypoxia (CH) enhances depolarization-induced myofilament Ca(2+) sensitization and resultant pulmonary arterial constriction through superoxide (O(2)(-))-dependent stimulation of RhoA. Because NAD(P)H oxidase (NOX) has been implicated in the development of pulmonary hypertension, we hypothesized that vascular smooth muscle (VSM) depolarization increases NOX-derived O(2)(-) production leading to myofilament Ca(2+) sensitization and augmented vasoconstrictor reactivity following CH. As epidermal growth factor receptor (EGFR) mediates Rac1-dependent NOX activation in renal mesangial cells, we further sought to examine the role EGFR plays in this response. RESULTS Vasoconstrictor responses to depolarizing concentrations of KCl were greater in lungs isolated from CH (4 wk, 0.5 atm) rats compared to normoxic controls, and this effect of CH was abolished by the general NOX inhibitor, apocynin. CH similarly augmented KCl-induced vasoconstriction and O(2)(-) generation (assessed using the fluorescent indicator, dihydroethidium) in Ca(2+)-permeabilized, pressurized small pulmonary arteries. These latter responses to CH were prevented by general inhibition of NOX isoforms (apocynin, diphenylene iodonium), and by selective inhibition of NOX 2 (gp91ds-tat), Rac1 (NSC 23766), and EGFR (AG 1478). Consistent with these observations, CH increased KCl-induced EGFR phosphorylation, and augmented depolarization-induced Rac1 activation in an EGFR-dependent manner. INNOVATION This study establishes a novel signaling axis in VSM linking membrane depolarization to contraction that is independent of Ca(2+) influx, and which mediates myofilament Ca(2+) sensitization in the hypertensive pulmonary circulation. CONCLUSION CH augments membrane depolarization-induced pulmonary VSM Ca(2+) sensitization and vasoconstriction through EGFR-dependent stimulation of Rac1 and NOX 2.
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Affiliation(s)
- Charles E Norton
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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33
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Wamsteeker Cusulin JI, Füzesi T, Inoue W, Bains JS. Glucocorticoid feedback uncovers retrograde opioid signaling at hypothalamic synapses. Nat Neurosci 2013; 16:596-604. [PMID: 23563581 PMCID: PMC4844536 DOI: 10.1038/nn.3374] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 03/05/2013] [Indexed: 01/11/2023]
Abstract
Stressful experience initiates a neuroendocrine response culminating in the release of glucocorticoid hormones into the blood. Glucocorticoids feed back to the brain causing adaptations that prevent excessive hormone responses to subsequent challenges. How these changes occur remains unknown. We report that glucocorticoid receptor activation in rodent hypothalamic neuroendocrine neurons following in vivo stress is a metaplastic signal that allows GABA synapses to undergo activity–dependent long–term depression (LTDGABA). LTDGABA is unmasked through glucocorticoid receptor inhibition of Regulator of G–protein Signaling 4 (RGS4), which amplifies signaling through postsynaptic metabotropic glutamate receptors (mGluRs). This drives somatodendritic opioid release, resulting in a persistent retrograde suppression of synaptic transmission through presynaptic μ–receptors. Together our data provide new evidence for retrograde opioid signaling at synapses in neuroendocrine circuits and represent a potential mechanism underlying GC contributions to stress adaptation.
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MacMillan D, Kennedy C, McCarron JG. ATP inhibits Ins(1,4,5)P3-evoked Ca2+ release in smooth muscle via P2Y1 receptors. J Cell Sci 2012; 125:5151-8. [PMID: 22899721 PMCID: PMC5704898 DOI: 10.1242/jcs.108498] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Adenosine 5′-triphosphate (ATP) mediates a variety of biological functions following nerve-evoked release, via activation of either G-protein-coupled P2Y- or ligand-gated P2X receptors. In smooth muscle, ATP, acting via P2Y receptors (P2YR), may act as an inhibitory neurotransmitter. The underlying mechanism(s) remain unclear, but have been proposed to involve the production of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] by phospholipase C (PLC), to evoke Ca2+ release from the internal store and stimulation of Ca2+-activated potassium (KCa) channels to cause membrane hyperpolarization. This mechanism requires Ca2+ release from the store. However, in the present study, ATP evoked transient Ca2+ increases in only ~10% of voltage-clamped single smooth muscle cells. These results do not support activation of KCa as the major mechanism underlying inhibition of smooth muscle activity. Interestingly, ATP inhibited Ins(1,4,5)P3-evoked Ca2+ release in cells that did not show a Ca2+ rise in response to purinergic activation. The reduction in Ins(1,4,5)P3-evoked Ca2+ release was not mimicked by adenosine and therefore, cannot be explained by hydrolysis of ATP to adenosine. The reduction in Ins(1,4,5)P3-evoked Ca2+ release was, however, also observed with its primary metabolite, ADP, and blocked by the P2Y1R antagonist, MRS2179, and the G protein inhibitor, GDPβS, but not by PLC inhibition. The present study demonstrates a novel inhibitory effect of P2Y1R activation on Ins(1,4,5)P3-evoked Ca2+ release, such that purinergic stimulation acts to prevent Ins(1,4,5)P3-mediated increases in excitability in smooth muscle and promote relaxation.
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Affiliation(s)
- D MacMillan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
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Optogenetic reporters: Fluorescent protein-based genetically encoded indicators of signaling and metabolism in the brain. PROGRESS IN BRAIN RESEARCH 2012; 196:235-63. [PMID: 22341329 DOI: 10.1016/b978-0-444-59426-6.00012-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fluorescent protein technology has evolved to include genetically encoded biosensors that can monitor levels of ions, metabolites, and enzyme activities as well as protein conformation and even membrane voltage. They are well suited to live-cell microscopy and quantitative analysis, and they can be used in multiple imaging modes, including one- or two-photon fluorescence intensity or lifetime microscopy. Although not nearly complete, there now exists a substantial set of genetically encoded reporters that can be used to monitor many aspects of neuronal and glial biology, and these biosensors can be used to visualize synaptic transmission and activity-dependent signaling in vitro and in vivo. In this review, we present an overview of design strategies for engineering biosensors, including sensor designs using circularly permuted fluorescent proteins and using fluorescence resonance energy transfer between fluorescent proteins. We also provide examples of indicators that sense small ions (e.g., pH, chloride, zinc), metabolites (e.g., glutamate, glucose, ATP, cAMP, lipid metabolites), signaling pathways (e.g., G protein-coupled receptors, Rho GTPases), enzyme activities (e.g., protein kinase A, caspases), and reactive species. We focus on examples where these genetically encoded indicators have been applied to brain-related studies and used with live-cell fluorescence microscopy.
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Hagenston AM, Bading H. Calcium signaling in synapse-to-nucleus communication. Cold Spring Harb Perspect Biol 2011; 3:a004564. [PMID: 21791697 DOI: 10.1101/cshperspect.a004564] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Changes in the intracellular concentration of calcium ions in neurons are involved in neurite growth, development, and remodeling, regulation of neuronal excitability, increases and decreases in the strength of synaptic connections, and the activation of survival and programmed cell death pathways. An important aspect of the signals that trigger these processes is that they are frequently initiated in the form of glutamatergic neurotransmission within dendritic trees, while their completion involves specific changes in the patterns of genes expressed within neuronal nuclei. Accordingly, two prominent aims of research concerned with calcium signaling in neurons are determination of the mechanisms governing information conveyance between synapse and nucleus, and discovery of the rules dictating translation of specific patterns of inputs into appropriate and specific transcriptional responses. In this article, we present an overview of the avenues by which glutamatergic excitation of dendrites may be communicated to the neuronal nucleus and the primary calcium-dependent signaling pathways by which synaptic activity can invoke changes in neuronal gene expression programs.
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Affiliation(s)
- Anna M Hagenston
- CellNetworks-Cluster of Excellence, Department of Neurobiology, Interdisciplinary Center for Neurosciences, University of Heidelberg, 69120 Heidelberg, Germany
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Chen X, Zhang X, Jia C, Xu J, Gao H, Zhang G, Du X, Zhang H. Membrane depolarization increases membrane PtdIns(4,5)P2 levels through mechanisms involving PKC βII and PI4 kinase. J Biol Chem 2011; 286:39760-7. [PMID: 21953466 DOI: 10.1074/jbc.m111.289090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In a previous study, we showed that membrane depolarization induced elevation of membrane phosphatidylinositol 4,5-bisphosphates (PtdIns(4,5)P(2), also known as PIP(2)) and subsequently increased the KCNQ2/Q3 currents expressed in Xenopus oocytes through increased PI4 kinase activity. In this study, the underlying mechanism for this depolarization-induced enhancement of PIP(2) synthesis was further investigated. Our results indicate that activation of protein kinase C (PKC) isozyme βII was responsible for the enhanced PIP(2) synthesis. We found that phorbol-12-myristate, 13-acetate (PMA), an activator of PKC, mimicked the effects of the membrane depolarization by increasing KCNQ2/Q3 activity, elevating membrane PIP(2) levels and increasing activity of PI4 kinase β. Furthermore, membrane depolarization enhanced PKC activity. The effects of both depolarization and PMA were blocked by a PKC inhibitor or PI4 kinase β RNA interference. Further results demonstrate that the depolarization selectively activated the PKC βII isoform and enhanced its interaction with PI4 kinase β. These results reveal that the depolarization-induced elevation of membrane PIP(2) is through activation of PKC and the subsequent increased activity of PI4 kinase β.
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Affiliation(s)
- Xingjuan Chen
- Key Laboratory of Neural and Vascular Biology, Ministry of Education, Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, 050017, China
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Marom M, Birnbaumer L, Atlas D. Membrane depolarization combined with Gq-activated G-protein-coupled receptors induce transient receptor potential channel 1 (TRPC1)- dependent potentiation of catecholamine release. Neuroscience 2011; 189:132-45. [DOI: 10.1016/j.neuroscience.2011.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/02/2011] [Accepted: 05/02/2011] [Indexed: 10/18/2022]
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Kommadath A, Woelders H, Beerda B, Mulder HA, de Wit AAC, Veerkamp RF, te Pas MFW, Smits MA. Gene expression patterns in four brain areas associate with quantitative measure of estrous behavior in dairy cows. BMC Genomics 2011; 12:200. [PMID: 21504592 PMCID: PMC3110153 DOI: 10.1186/1471-2164-12-200] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Accepted: 04/19/2011] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The decline noticed in several fertility traits of dairy cattle over the past few decades is of major concern. Understanding of the genomic factors underlying fertility, which could have potential applications to improve fertility, is very limited. Here, we aimed to identify and study those genes that associated with a key fertility trait namely estrous behavior, among genes expressed in four bovine brain areas (hippocampus, amygdala, dorsal hypothalamus and ventral hypothalamus), either at the start of estrous cycle, or at mid cycle, or regardless of the phase of cycle. RESULTS An average heat score was calculated for each of 28 primiparous cows in which estrous behavior was recorded for at least two consecutive estrous cycles starting from 30 days post-partum. Gene expression was then measured in brain tissue samples collected from these cows, 14 of which were sacrificed at the start of estrus and 14 around mid cycle. For each brain area, gene expression was modeled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model. Genes whose expression patterns showed significant linear or quadratic relationships with heat scores were identified. These included genes expected to be related to estrous behavior as they influence states like socio-sexual behavior, anxiety, stress and feeding motivation (OXT, AVP, POMC, MCHR1), but also genes whose association with estrous behavior is novel and warrants further investigation. CONCLUSIONS Several genes were identified whose expression levels in the bovine brain associated with the level of expression of estrous behavior. The genes OXT and AVP play major roles in regulating estrous behavior in dairy cows. Genes related to neurotransmission and neuronal plasticity are also involved in estrous regulation, with several genes and processes expressed in mid-cycle probably contributing to proper expression of estrous behavior in the next estrus. Studying these genes and the processes they control improves our understanding of the genomic regulation of estrous behavior expression.
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Affiliation(s)
- Arun Kommadath
- Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, Lelystad, The Netherlands.
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Chen SR, Chen H, Yuan WX, Wess J, Pan HL. Dynamic control of glutamatergic synaptic input in the spinal cord by muscarinic receptor subtypes defined using knockout mice. J Biol Chem 2010; 285:40427-37. [PMID: 20940295 DOI: 10.1074/jbc.m110.176966] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of muscarinic acetylcholine receptors (mAChRs) in the spinal cord inhibits pain transmission. At least three mAChR subtypes (M(2), M(3), and M(4)) are present in the spinal dorsal horn. However, it is not clear how each mAChR subtype contributes to the regulation of glutamatergic input to dorsal horn neurons. We recorded spontaneous excitatory postsynaptic currents (sEPSCs) from lamina II neurons in spinal cord slices from wild-type (WT) and mAChR subtype knock-out (KO) mice. The mAChR agonist oxotremorine-M increased the frequency of glutamatergic sEPSCs in 68.2% neurons from WT mice and decreased the sEPSC frequency in 21.2% neurons. Oxotremorine-M also increased the sEPSC frequency in ∼50% neurons from M(3)-single KO and M(1)/M(3) double-KO mice. In addition, the M(3) antagonist J104129 did not block the stimulatory effect of oxotremorine-M in the majority of neurons from WT mice. Strikingly, in M(5)-single KO mice, oxotremorine-M increased sEPSCs in only 26.3% neurons, and J104129 abolished this effect. In M(2)/M(4) double-KO mice, but not M(2)- or M(4)-single KO mice, oxotremorine-M inhibited sEPSCs in significantly fewer neurons compared with WT mice, and blocking group II/III metabotropic glutamate receptors abolished this effect. The M(2)/M(4) antagonist himbacine either attenuated the inhibitory effect of oxotremorine-M or potentiated the stimulatory effect of oxotremorine-M in WT mice. Our study demonstrates that activation of the M(2) and M(4) receptor subtypes inhibits synaptic glutamate release to dorsal horn neurons. M(5) is the predominant receptor subtype that potentiates glutamatergic synaptic transmission in the spinal cord.
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Affiliation(s)
- Shao-Rui Chen
- Department of Anesthesiology and Perioperative Medicine, The University of Texas, M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Opazo F, Schulz JB, Falkenburger BH. PKC links Gq-coupled receptors to DAT-mediated dopamine release. J Neurochem 2010; 114:587-96. [DOI: 10.1111/j.1471-4159.2010.06788.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Martinez-Pinna J, Gurung IS, Mahaut-Smith MP, Morales A. Direct voltage control of endogenous lysophosphatidic acid G-protein-coupled receptors in Xenopus oocytes. J Physiol 2010; 588:1683-93. [PMID: 20351041 DOI: 10.1113/jphysiol.2009.183418] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Lysophosphatidic acid (LPA) G-protein-coupled receptors (GPCRs) play important roles in a variety of physiological and pathophysiological processes, including cell proliferation, angiogenesis, central nervous system development and carcinogenesis. Whilst many ion channels and transporters are recognized to be controlled by a change in cell membrane potential, little is known about the voltage dependence of other proteins involved in cell signalling. Here, we show that the InsP(3)-mediated Ca(2+) response stimulated by the endogenous LPA GPCR in Xenopus oocytes is potentiated by membrane depolarization. Depolarization was able to repetitively stimulate transient [Ca(2+)](i) increases after the initial agonist-evoked response. In addition, the initial rate and amplitude of the LPA-dependent Ca(2+) response were significantly modulated by the steady holding potential over the physiological range, such that the response to LPA was potentiated at depolarized potentials and inhibited at hyperpolarized potentials. Enhancement of LPA receptor-evoked Ca(2+) mobilization by membrane depolarization was observed over a wide range of agonist concentrations. Importantly, the amplitude of the depolarization-evoked intracellular Ca(2+) increase displayed an inverse relationship with agonist concentration such that the greatest effect of voltage was observed at near-threshold levels of agonist. Voltage-dependent Ca(2+) release was not induced by direct elevation of InsP(3) or by activation of heterotrimeric G-proteins in the absence of agonist, indicating that the LPA GPCR itself represents the primary site of action of membrane voltage. This novel modulation of LPA signalling by membrane potential may have important consequences for control of Ca(2+) signals both in excitable and non-excitable tissues.
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Affiliation(s)
- Juan Martinez-Pinna
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, E-03080, Spain.
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Zhang X, Chen X, Jia C, Geng X, Du X, Zhang H. Depolarization increases phosphatidylinositol (PI) 4,5-bisphosphate level and KCNQ currents through PI 4-kinase mechanisms. J Biol Chem 2010; 285:9402-9409. [PMID: 20106968 DOI: 10.1074/jbc.m109.068205] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A growing body of evidence shows that membrane phosphatidylinositol 4,5-bisphosphates (PtdIns(4,5)P(2), PIP(2)) play an important role in cell signaling. The presence of PIP(2) is fundamentally important for maintaining the functions of a large number of ion channels and transporters, and for other cell processes such as vesicle trafficking, mobility, and endo- and exocytosis. PIP(2) levels in the membrane are dynamically modulated, which is an important signaling mechanism for modulation of PIP(2)-dependent cellular processes. In this study, we describe a novel mechanism of membrane PIP(2) modulation. Membrane depolarization induces an elevation in membrane PIP(2), and subsequently increases functions of PIP(2)-sensitive KCNQ potassium channels expressed in Xenopus oocytes. Further evidence suggests that the depolarization-induced elevation of membrane PIP(2) occurs through increased activity of PI4 kinase. With increased recognition of the importance of PIP(2) in cell function, the effect of membrane depolarization in PIP(2) metabolism is destined to have important physiological implications.
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Affiliation(s)
- Xuan Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Xingjuan Chen
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Caixia Jia
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Xian Geng
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Xiaona Du
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
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Capone R, Quiroz FG, Prangkio P, Saluja I, Sauer AM, Bautista MR, Turner RS, Yang J, Mayer M. Amyloid-beta-induced ion flux in artificial lipid bilayers and neuronal cells: resolving a controversy. Neurotox Res 2009; 16:1-13. [PMID: 19526294 PMCID: PMC2864106 DOI: 10.1007/s12640-009-9033-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 12/15/2008] [Accepted: 12/15/2008] [Indexed: 10/20/2022]
Abstract
Understanding the pathogenicity of amyloid-beta (Abeta) peptides constitutes a major goal in research on Alzheimer's disease (AD). One hypothesis entails that Abeta peptides induce uncontrolled, neurotoxic ion flux through cellular membranes. The exact biophysical mechanism of this ion flux is, however, a subject of an ongoing controversy which has attenuated progress toward understanding the importance of Abeta-induced ion flux in AD. The work presented here addresses two prevalent controversies regarding the nature of transmembrane ion flux induced by Alphabeta peptides. First, the results clarify that Alphabeta can induce stepwise ion flux across planar lipid bilayers as opposed to a gradual increase in transmembrane current; they show that the previously reported gradual thinning of membranes with concomitant increase in transmembrane current arises from residues of the solvent hexafluoroisopropanol, which is commonly used for the preparation of amyloid samples. Second, the results provide additional evidence suggesting that Abeta peptides can induce ion channel-like ion flux in cellular membranes that is independent from the postulated ability of Alphabeta to modulate intrinsic cellular ion channels or transporter proteins.
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Affiliation(s)
- Ricardo Capone
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Ave, Ann Arbor, MI 48109-2110, USA
| | - Felipe Garcia Quiroz
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Ave, Ann Arbor, MI 48109-2110, USA
| | - Panchika Prangkio
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Ave, Ann Arbor, MI 48109-2110, USA
| | | | - Anna M. Sauer
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Ave, Ann Arbor, MI 48109-2110, USA
| | - Mahealani R. Bautista
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, CA 92093-0358, USA
| | | | - Jerry Yang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, CA 92093-0358, USA
| | - Michael Mayer
- Departments of Biomedical Engineering and Chemical Engineering, University of Michigan, 1101 Beal Ave, Ann Arbor, MI 48109-2110, USA
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Membrane depolarization causes a direct activation of G protein-coupled receptors leading to local Ca2+ release in smooth muscle. Proc Natl Acad Sci U S A 2009; 106:11418-23. [PMID: 19549818 DOI: 10.1073/pnas.0813307106] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane depolarization activates voltage-dependent Ca(2+) channels (VDCCs) inducing Ca(2+) release via ryanodine receptors (RyRs), which is obligatory for skeletal and cardiac muscle contraction and other physiological responses. However, depolarization-induced Ca(2+) release and its functional importance as well as underlying signaling mechanisms in smooth muscle cells (SMCs) are largely unknown. Here we report that membrane depolarization can induce RyR-mediated local Ca(2+) release, leading to a significant increase in the activity of Ca(2+) sparks and contraction in airway SMCs. The increased Ca(2+) sparks are independent of VDCCs and the associated extracellular Ca(2+) influx. This format of local Ca(2+) release results from a direct activation of G protein-coupled, M(3) muscarinic receptors in the absence of exogenous agonists, which causes activation of Gq proteins and phospholipase C, and generation of inositol 1,4,5-triphosphate (IP(3)), inducing initial Ca(2+) release through IP(3) receptors and then further Ca(2+) release via RyR2 due to a local Ca(2+)-induced Ca(2+) release process. These findings demonstrate an important mechanism for Ca(2+) signaling and attendant physiological function in SMCs.
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Rango M, Cogiamanian F, Marceglia S, Barberis B, Arighi A, Biondetti P, Priori A. Myoinositol content in the human brain is modified by transcranial direct current stimulation in a matter of minutes: a 1H-MRS study. Magn Reson Med 2009; 60:782-9. [PMID: 18816828 DOI: 10.1002/mrm.21709] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Brain content of myoinositol (mI) has been shown to be altered in several neuropsychiatric conditions. Likewise, various forms of electric currents have been applied to the human brain for therapeutic purposes in neuropsychiatric diseases. In this study we aimed to depict the effects of low-power transcranial direct current stimulation (tDCS) on brain mI by proton magnetic resonance spectroscopy ((1)H-MRS). We studied two groups of five healthy subjects by (1)H-MRS: the first group was studied before and after both anodal and sham (placebo) tDCS over the right frontal lobe, and the second group was studied at the same intervals without undergoing either sham or anodal tDCS. Anodal tDCS induced a significant increase of mI content at 30 min after stimulation offset (141.5 +/- 16.7%, P < 0.001) below the stimulating electrode but not in distant regions, such as the visual cortex, whereas sham tDCS failed to induce changes in mI. Neither N-acetyl-aspartate (NAA) nor the other metabolite contents changed after anodal or sham stimulation. (1)H-MRS represents a powerful tool to follow the regional effects of tDCS on brain mI and, possibly, on the related phosphoinositide system.
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Affiliation(s)
- M Rango
- Department of Neurological Sciences, University of Milan, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Ospedale Maggiore Policlinico Mangiagalli e Regina Elena, Milan, Italy
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Mahaut-Smith MP, Martinez-Pinna J, Gurung IS. A role for membrane potential in regulating GPCRs? Trends Pharmacol Sci 2008; 29:421-9. [PMID: 18621424 DOI: 10.1016/j.tips.2008.05.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 05/16/2008] [Accepted: 05/28/2008] [Indexed: 10/21/2022]
Abstract
G-protein-coupled receptors (GPCRs) have ubiquitous roles in transducing extracellular signals into cellular responses. Therefore, the concept that members of this superfamily of surface proteins are directly modulated by changes in membrane voltage could have widespread consequences for cell signalling. Although several studies have indicated that GPCRs can be voltage dependent, particularly P2Y(1) receptors in the non-excitable megakaryocyte, the evidence has been mostly indirect. Recent work on muscarinic receptors has stimulated substantial interest in this field by reporting the first voltage-dependent charge movements for a GPCR. An underlying mechanism is proposed whereby a voltage-induced conformational change in the receptor alters its ability to couple to the G protein and thereby influences its affinity for an agonist. We discuss the strength of the evidence behind this hypothesis and include suggestions for future work. We also describe other examples in which direct voltage control of GPCRs can account for effects of membrane potential on downstream signals and highlight the possible physiological consequences of this phenomenon.
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Affiliation(s)
- Martyn P Mahaut-Smith
- Department of Cell Physiology and Pharmacology, University of Leicester, LE1 9HN, UK.
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Gurung IS, Martinez-Pinna J, Mahaut-Smith MP. Novel consequences of voltage-dependence to G-protein-coupled P2Y1 receptors. Br J Pharmacol 2008; 154:882-9. [PMID: 18414379 DOI: 10.1038/bjp.2008.97] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE Emerging evidence suggests that activation of G-protein-coupled receptors (GPCRs) can be directly regulated by membrane voltage. However, the physiological and pharmacological relevance of this effect remains unclear. We have further examined this phenomenon for P2Y1 receptors in the non-excitable megakaryocyte using a range of agonists and antagonists. EXPERIMENTAL APPROACH Simultaneous whole-cell patch clamp and fura-2 fluorescence recordings of rat megakaryocytes, which lack voltage-gated Ca2+ influx, were used to examine the voltage-dependence of P2Y1 receptor-evoked IP3-dependent Ca2+ mobilization. RESULTS Depolarization transiently and repeatedly enhanced P2Y1 receptor-evoked Ca2+ mobilization across a wide concentration range of both weak, partial and full, potent agonists. Moreover, the amplitude of the depolarization-evoked [Ca2+]i increase displayed an inverse relationship with agonist concentration, such that the greatest potentiating effect of voltage was observed at near-threshold levels of agonist. Unexpectedly, depolarization also stimulated an [Ca2+]i increase in the absence of agonist during exposure to the competitive antagonists A3P5PS and MRS2179, or the allosteric enhancer 2,2'-pyridylisatogen tosylate. A further effect of some antagonists, particularly suramin, was to enhance the depolarization-evoked Ca2+ responses during co-application of an agonist. Of several P2Y1 receptor inhibitors, only SCH202676, which has a proposed allosteric mechanism of action, could block ADP-induced voltage-dependent Ca2+ release. CONCLUSIONS AND IMPLICATIONS The ability of depolarization to potentiate GPCRs at near-threshold agonist concentrations represents a novel mechanism for coincidence detection. Furthermore, the induction and enhancement of voltage-dependent GPCR responses by antagonists has implications for the design of therapeutic compounds.
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Affiliation(s)
- I S Gurung
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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Raymond CR. Different requirements for action potentials in the induction of different forms of long-term potentiation. J Physiol 2008; 586:1859-65. [PMID: 18276728 DOI: 10.1113/jphysiol.2008.151035] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The role of postsynaptic action potentials (APs) in the induction of long-term potentiation (LTP) remains unclear, but has important implications for theories of associative learning in the brain. In area CA1 of hippocampus, at least three discrete forms of LTP coexist, each displaying unique decay kinetics and involving different signalling and effector systems. The present work investigates whether these forms of LTP also differ in their requirement for postsynaptic APs. Inhibition of APs during theta-burst stimulation (TBS) had no effect on the persistence of short-lasting LTP (LTP 1), but reduced the persistence of more durable forms (LTP 2 and 3). Calcium imaging revealed different requirements for APs in generating calcium signals in spines, dendrites, and somata, consistent with their known roles in the induction of each form of LTP. Finally, short-lasting LTP was endowed with dramatically enhanced persistence by the presentation of TBS-patterned APs alone. These data reveal that the requirement for APs in LTP induction is dependent on the form of LTP under investigation, supporting the contention that different neuronal learning mechanisms coexist in hippocampal area CA1.
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Affiliation(s)
- Clarke R Raymond
- Division of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia.
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50
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Zhdanov AV, Ward MW, Prehn JHM, Papkovsky DB. Dynamics of intracellular oxygen in PC12 Cells upon stimulation of neurotransmission. J Biol Chem 2007; 283:5650-61. [PMID: 18086678 DOI: 10.1074/jbc.m706439200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurotransmission, synaptic plasticity, and maintenance of membrane excitability require high mitochondrial activity in neurosecretory cells. Using a fluorescence-based intracellular O2 sensing technique, we investigated the respiration of differentiated PC12 cells upon depolarization with 100 mm K+. Single cell confocal analysis identified a significant depolarization of the plasma membrane potential and a relatively minor depolarization of the mitochondrial membrane potential following K+ exposure. We observed a two-phase respiratory response: a first intense spike lasting approximately 10 min, during which average intracellular O2 was reduced from 85-90% of air saturation to 55-65%, followed by a second wave of smaller amplitude and longer duration. The fast rise in O2 consumption coincided with a transient increase in cellular ATP by approximately 60%, which was provided largely by oxidative phosphorylation and by glycolysis. The increase of respiration was orchestrated mainly by Ca2+ release from the endoplasmic reticulum, whereas the influx of extracellular Ca2+ contributed approximately 20%. Depletion of Ca2+ stores by ryanodine, thapsigargin, and 4-chloro-m-cresol reduced the amplitude of respiratory spike by 45, 63, and 71%, respectively, whereas chelation of intracellular Ca2+ abolished the response. Uncoupling of the mitochondria with the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone amplified the responses to K+; elevated respiration induced a profound deoxygenation without increasing the cellular ATP levels reduced by carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Cleavage of synaptobrevin 2 by tetanus toxin, known to reduce neurotransmission, did not affect the respiratory response to K+, whereas the general excitability of d PC12 cells increased.
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Affiliation(s)
- Alexander V Zhdanov
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, Cork, Ireland
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