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Li S, Zheng Y, Kang Y, He X, Zheng Y, Jiang M, Xu X, Ma L, Wang X, Zhang K, Shao X, Fang J, Jiang Y. Electroacupuncture alleviates streptozotocin-induced diabetic neuropathic pain via suppressing phosphorylated CaMKIIα in rats. Neuroreport 2024; 35:258-268. [PMID: 38305135 PMCID: PMC10852042 DOI: 10.1097/wnr.0000000000002000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024]
Abstract
Diabetic neuropathic pain (DNP) is a frequent complication of diabetes. Calcium/calmodulin-dependent protein kinase II α (CaMKIIα), a multi-functional serine/threonine kinase subunit, is mainly located in the surface layer of the spinal cord dorsal horn (SCDH) and the primary sensory neurons in dorsal root ganglion (DRG). Numerous studies have indicated electroacupuncture (EA) takes effect in various kinds of pain. In this research, we explored whether CaMKIIα on rats' SCDH and DRG participated in DNP and further explored the mechanisms underlying the analgesic effects of EA. The DNP model in rats was successfully established by intraperitoneal injection of streptozotocin. Certain DNP rats were treated with intrathecal injections of KN93, a CaMKII antagonist, and some of the DNP rats received EA intervention. The general conditions, behaviors, the expressions of CaMKIIα and phosphorylated CaMKIIα (p-CaMKIIα) were evaluated. DNP rats' paw withdrawal threshold was reduced and the expressions of p-CaMKIIα in SCDH and DRG were upregulated compared with the Normal group, while the level of CaMKIIα showed no significance. KN93 attenuated DNP rats' hyperalgesia and reduced the expressions of p-CaMKIIα. We also found EA attenuated the hyperalgesia of DNP rats and reduced the expressions of p-CaMKIIα. The above findings suggest that p-CaMKIIα in SCDH and DRG is involved in DNP. The analgesic effect of EA in DNP might be related to the downregulation of p-CaMKIIα expression level. Our study further supports that EA can be an effective clinical treatment for DNP.
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Affiliation(s)
- Siyi Li
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Yinmu Zheng
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Yurong Kang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Xiaofen He
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Yu Zheng
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Minjian Jiang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Xinnan Xu
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Liqian Ma
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Xiaoxiang Wang
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Kunlong Zhang
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Xiaomei Shao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Jianqiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
| | - Yongliang Jiang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, People’s Republic of China
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Chiang M, Lin Y, Zhao W, Liu H, Hsu R, Chou T, Lu T, Lee I, Liao L, Chiou S, Chu L, Hu S. In Situ Forming of Nitric Oxide and Electric Stimulus for Nerve Therapy by Wireless Chargeable Gold Yarn-Dynamos. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303566. [PMID: 37867218 PMCID: PMC10667856 DOI: 10.1002/advs.202303566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/14/2023] [Indexed: 10/24/2023]
Abstract
Endogenous signals, namely nitric oxide (NO) and electrons, play a crucial role in regulating cell fate as well as the vascular and neuronal systems. Unfortunately, utilizing NO and electrical stimulation in clinical settings can be challenging due to NO's short half-life and the invasive electrodes required for electrical stimulation. Additionally, there is a lack of tools to spatiotemporally control gas release and electrical stimulation. To address these issues, an "electromagnetic messenger" approach that employs on-demand high-frequency magnetic field (HFMF) to trigger NO release and electrical stimulation for restoring brain function in cases of traumatic brain injury is introduced. The system comprises a NO donor (poly(S-nitrosoglutathione), pGSNO)-conjugated on a gold yarn-dynamos (GY) and embedded in an implantable silk in a microneedle. When subjected to HFMF, conductive GY induces eddy currents that stimulate the release of NO from pGSNO. This process significantly enhances neural stem cell (NSC) synapses' differentiation and growth. The combined strategy of using NO and electrical stimulation to inhibit inflammation, angiogenesis, and neuronal interrogation in traumatic brain injury is demonstrated in vivo.
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Affiliation(s)
- Min‐Ren Chiang
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Ya‐Hui Lin
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
- Brain Research CenterNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Wei‐Jie Zhao
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Hsiu‐Ching Liu
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Ru‐Siou Hsu
- Department of ChemistryStanford UniversityStanfordCA94305USA
| | - Tsu‐Chin Chou
- Institute of Analytical and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Tsai‐Te Lu
- Institute of Biomedical EngineeringNational Tsing Hua UniversityHsinchu300044Taiwan
- Department of ChemistryNational Tsing Hua UniversityHsinchu300044Taiwan
- Department of ChemistryChung Yuan Christian UniversityTaoyuan320314Taiwan
| | - I‐Chi Lee
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Lun‐De Liao
- Institute of Biomedical Engineering and NanomedicineNational Health Research InstitutesMiaoli County35053Taiwan
| | - Shih‐Hwa Chiou
- Institute of PharmacologyCollege of MedicineNational Yang Ming Chiao Tung UniversityTaipei112304Taiwan
- Department of Medical ResearchTaipei Veterans General HospitalTaipei112201Taiwan
| | - Li‐An Chu
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
- Brain Research CenterNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Shang‐Hsiu Hu
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
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3
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Autonomous rhythmic activity in glioma networks drives brain tumour growth. Nature 2023; 613:179-186. [PMID: 36517594 DOI: 10.1038/s41586-022-05520-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 11/03/2022] [Indexed: 12/23/2022]
Abstract
Diffuse gliomas, particularly glioblastomas, are incurable brain tumours1. They are characterized by networks of interconnected brain tumour cells that communicate via Ca2+ transients2-6. However, the networks' architecture and communication strategy and how these influence tumour biology remain unknown. Here we describe how glioblastoma cell networks include a small, plastic population of highly active glioblastoma cells that display rhythmic Ca2+ oscillations and are particularly connected to others. Their autonomous periodic Ca2+ transients preceded Ca2+ transients of other network-connected cells, activating the frequency-dependent MAPK and NF-κB pathways. Mathematical network analysis revealed that glioblastoma network topology follows scale-free and small-world properties, with periodic tumour cells frequently located in network hubs. This network design enabled resistance against random damage but was vulnerable to losing its key hubs. Targeting of autonomous rhythmic activity by selective physical ablation of periodic tumour cells or by genetic or pharmacological interference with the potassium channel KCa3.1 (also known as IK1, SK4 or KCNN4) strongly compromised global network communication. This led to a marked reduction of tumour cell viability within the entire network, reduced tumour growth in mice and extended animal survival. The dependency of glioblastoma networks on periodic Ca2+ activity generates a vulnerability7 that can be exploited for the development of novel therapies, such as with KCa3.1-inhibiting drugs.
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Mi J, Xu J, Yao Z, Yao H, Li Y, He X, Dai B, Zou L, Tong W, Zhang X, Hu P, Ruan YC, Tang N, Guo X, Zhao J, He J, Qin L. Implantable Electrical Stimulation at Dorsal Root Ganglions Accelerates Osteoporotic Fracture Healing via Calcitonin Gene-Related Peptide. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103005. [PMID: 34708571 PMCID: PMC8728818 DOI: 10.1002/advs.202103005] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/11/2021] [Indexed: 05/18/2023]
Abstract
The neuronal engagement of the peripheral nerve system plays a crucial role in regulating fracture healing, but how to modulate the neuronal activity to enhance fracture healing remains unexploited. Here it is shown that electrical stimulation (ES) directly promotes the biosynthesis and release of calcitonin gene-related peptide (CGRP) by activating Ca2+ /CaMKII/CREB signaling pathway and action potential, respectively. To accelerate rat femoral osteoporotic fracture healing which presents with decline of CGRP, soft electrodes are engineered and they are implanted at L3 and L4 dorsal root ganglions (DRGs). ES delivered at DRGs for the first two weeks after fracture increases CGRP expression in both DRGs and fracture callus. It is also identified that CGRP is indispensable for type-H vessel formation, a biological event coupling angiogenesis and osteogenesis, contributing to ES-enhanced osteoporotic fracture healing. This proof-of-concept study shows for the first time that ES at lumbar DRGs can effectively promote femoral fracture healing, offering an innovative strategy using bioelectronic device to enhance bone regeneration.
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Affiliation(s)
- Jie Mi
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
- Shanghai Key Laboratory of Orthopaedic ImplantsDepartment of OrthopaedicsShanghai Ninth People's HospitalShanghai Jiao Tong University School of Medicine639 Zhizaoju RoadShanghai200011People's Republic of China
| | - Jian‐Kun Xu
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Zhi Yao
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Hao Yao
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Ye Li
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Xuan He
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Bing‐Yang Dai
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Li Zou
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Wen‐Xue Tong
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Xiao‐Tian Zhang
- Department of Biomedical EngineeringThe Hong Kong Polytechnic UniversityHung Hom999077Hong Kong
| | - Pei‐Jie Hu
- Department of Biomedical EngineeringThe Hong Kong Polytechnic UniversityHung Hom999077Hong Kong
| | - Ye Chun Ruan
- Department of Biomedical EngineeringThe Hong Kong Polytechnic UniversityHung Hom999077Hong Kong
| | - Ning Tang
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
| | - Xia Guo
- Department of Biomedical EngineeringThe Hong Kong Polytechnic UniversityHung Hom999077Hong Kong
| | - Jie Zhao
- Shanghai Key Laboratory of Orthopaedic ImplantsDepartment of OrthopaedicsShanghai Ninth People's HospitalShanghai Jiao Tong University School of Medicine639 Zhizaoju RoadShanghai200011People's Republic of China
| | - Ju‐Fang He
- Departments of Neuroscience and Biomedical SciencesCity University of Hong KongKowloon Tong999077Hong Kong
| | - Ling Qin
- Musculoskeletal Research LaboratoryDepartment of Orthopedics & TraumatologyInnovative Orthopaedic Biomaterial and Drug Translational Research LaboratoryLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongHong Kong999077China
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Abstract
The function of the nervous system in conveying and processing information necessary to interact with the environment confers unique aspects on how the expression of genes in neurons is regulated. Three salient factors are that (1) neurons are the largest and among the most morphologically complex of all cells, with strict polarity, subcellular compartmentation, and long-distant transport of gene products, signaling molecules, and other materials; (2) information is coded in the temporal firing pattern of membrane depolarization; and (3) neurons must maintain a stable homeostatic level of activation to function so stimuli do not normally drive intracellular signaling to steady state. Each of these factors can require special methods of analysis differing from approaches used in non-neuronal cells. This review considers these three aspects of neuronal gene expression and the current approaches being used to analyze these special features of how the neuronal transcriptome is modulated by action potential firing.
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Affiliation(s)
- Philip R. Lee
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - R. Douglas Fields
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
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6
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Bhattacharyya M, Karandur D, Kuriyan J. Structural Insights into the Regulation of Ca 2+/Calmodulin-Dependent Protein Kinase II (CaMKII). Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035147. [PMID: 31653643 DOI: 10.1101/cshperspect.a035147] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a highly conserved serine/threonine kinase that is ubiquitously expressed throughout the human body. Specialized isoforms of CaMKII play key roles in neuronal and cardiac signaling. The distinctive holoenzyme architecture of CaMKII, with 12-14 kinase domains attached by flexible linkers to a central hub, poses formidable challenges for structural characterization. Nevertheless, progress in determining the structural mechanisms underlying CaMKII functions has come from studying the kinase domain and the hub separately, as well as from a recent electron microscopic investigation of the intact holoenzyme. In this review, we discuss our current understanding of the structure of CaMKII. We also discuss the intriguing finding that the CaMKII holoenzyme can undergo activation-triggered subunit exchange, a process that has implications for the potentiation and perpetuation of CaMKII activity.
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Affiliation(s)
- Moitrayee Bhattacharyya
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720.,Howard Hughes Medical Institute, University of California, Berkeley, California 94720
| | - Deepti Karandur
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720.,Howard Hughes Medical Institute, University of California, Berkeley, California 94720
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720.,Howard Hughes Medical Institute, University of California, Berkeley, California 94720.,Department of Chemistry, University of California, Berkeley, California 94720.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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7
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Aperia A, Brismar H, Uhlén P. Mending Fences: Na,K-ATPase signaling via Ca 2+ in the maintenance of epithelium integrity. Cell Calcium 2020; 88:102210. [PMID: 32380435 DOI: 10.1016/j.ceca.2020.102210] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/18/2022]
Abstract
Na,K-ATPase is a ubiquitous multifunctional protein that acts both as an ion pump and as a signal transducer. The signaling function is activated by ouabain in non-toxic concentrations. In epithelial cells the ouabain-bound Na,K-ATPase connects with the inositol 1,4,5-trisphosphate receptor via a short linear motif to activate low frequency Ca2+ oscillations. Within a couple of minutes this ouabain mediated signal has resulted in phosphorylation or dephosphorylation of 2580 phospho-sites. Proteins that control cell proliferation and cell adhesion and calmodulin regulated proteins are enriched among the ouabain phosphor-regulated proteins. The inositol 1,4,5-trisphosphate receptor and the stromal interaction molecule, which are both essential for the initiation of Ca2+ oscillations, belong to the ouabain phosphor-regulated proteins. Downstream effects of the ouabain-evoked Ca2+ signal in epithelial cells include interference with the intrinsic mitochondrial apoptotic process and stimulation of embryonic growth processes. The dual function of Na,K-ATPase as an ion pump and a signal transducer is now well established and evaluation of the physiological and pathophysiological consequences of this universal signal emerges as an urgent topic for future studies.
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Affiliation(s)
- Anita Aperia
- Science for Life Laboratory, Dept of Women's and Children's Health, Karolinska Institutet, Sweden
| | - Hjalmar Brismar
- Science for Life Laboratory, Dept of Women's and Children's Health, Karolinska Institutet, Sweden; Science for Life Laboratory, Dept of Applied Physics, KTH Royal Institute of Technology, Sweden.
| | - Per Uhlén
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Sweden
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8
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Takla M, Huang CLH, Jeevaratnam K. The cardiac CaMKII-Na v1.5 relationship: From physiology to pathology. J Mol Cell Cardiol 2020; 139:190-200. [PMID: 31958466 DOI: 10.1016/j.yjmcc.2019.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/20/2019] [Accepted: 12/30/2019] [Indexed: 12/19/2022]
Abstract
The SCN5A gene encodes Nav1.5, which, as the cardiac voltage-gated Na+ channel's pore-forming α subunit, is crucial for the initiation and propagation of atrial and ventricular action potentials. The arrhythmogenic propensity of inherited SCN5A mutations implicates the Na+ channel in determining cardiomyocyte excitability under normal conditions. Cytosolic kinases have long been known to alter the kinetic profile of Nav1.5 inactivation via phosphorylation of specific residues. Recent substantiation of both the role of calmodulin-dependent kinase II (CaMKII) in modulating the properties of the Nav1.5 inactivation gate and the significant rise in oxidation-dependent autonomous CaMKII activity in structural heart disease has raised the possibility of a novel pathway for acquired arrhythmias - the CaMKII-Nav1.5 relationship. The aim of this review is to: (1) outline the relationship's translation from physiological adaptation to pathological vicious circle; and (2) discuss the relative merits of each of its components as pharmacological targets.
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Affiliation(s)
- Michael Takla
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom
| | - Christopher L-H Huang
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom; Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom; Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom.
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9
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Tyssowski KM, Gray JM. The neuronal stimulation-transcription coupling map. Curr Opin Neurobiol 2019; 59:87-94. [PMID: 31163285 PMCID: PMC6885097 DOI: 10.1016/j.conb.2019.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/06/2019] [Indexed: 12/17/2022]
Abstract
Neurons transcribe different genes in response to different extracellular stimuli, and these genes regulate neuronal plasticity. Thus, understanding how different stimuli regulate different stimulus-dependent gene modules would deepen our understanding of plasticity. To systematically dissect the coupling between stimulation and transcription, we propose creating a 'stimulation-transcription coupling map' that describes the transcription response to each possible extracellular stimulus. While we are currently far from having a complete map, recent genomic experiments have begun to facilitate its creation. Here, we describe the current state of the stimulation-transcription coupling map as well as the transcriptional regulation that enables this coupling.
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Affiliation(s)
- Kelsey M Tyssowski
- Harvard Medical School, Department of Genetics, 77 Ave Louis Pasteur, Boston, MA 02115, United States
| | - Jesse M Gray
- Harvard Medical School, Department of Genetics, 77 Ave Louis Pasteur, Boston, MA 02115, United States.
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10
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Ohadi D, Schmitt DL, Calabrese B, Halpain S, Zhang J, Rangamani P. Computational Modeling Reveals Frequency Modulation of Calcium-cAMP/PKA Pathway in Dendritic Spines. Biophys J 2019; 117:1963-1980. [PMID: 31668749 PMCID: PMC7031750 DOI: 10.1016/j.bpj.2019.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Dendritic spines are the primary excitatory postsynaptic sites that act as subcompartments of signaling. Ca2+ is often the first and most rapid signal in spines. Downstream of calcium, the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway plays a critical role in the regulation of spine formation, morphological modifications, and ultimately, learning and memory. Although the dynamics of calcium are reasonably well-studied, calcium-induced cAMP/PKA dynamics, particularly with respect to frequency modulation, are not fully explored. In this study, we present a well-mixed model for the dynamics of calcium-induced cAMP/PKA dynamics in dendritic spines. The model is constrained using experimental observations in the literature. Further, we measured the calcium oscillation frequency in dendritic spines of cultured hippocampal CA1 neurons and used these dynamics as model inputs. Our model predicts that the various steps in this pathway act as frequency modulators for calcium, and the high frequency of calcium input is filtered by adenylyl cyclase 1 and phosphodiesterases in this pathway such that cAMP/PKA only responds to lower frequencies. This prediction has important implications for noise filtering and long-timescale signal transduction in dendritic spines. A companion manuscript presents a three-dimensional spatial model for the same pathway.
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Affiliation(s)
- Donya Ohadi
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California
| | - Danielle L Schmitt
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Barbara Calabrese
- Division of Biological Sciences and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California
| | - Shelley Halpain
- Division of Biological Sciences and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California.
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11
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Sforna L, Franciolini F, Catacuzzeno L. Ca 2+ -dependent and Ca 2+ -independent somatic release from trigeminal neurons. J Cell Physiol 2018; 234:10977-10989. [PMID: 30536400 DOI: 10.1002/jcp.27901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/25/2018] [Indexed: 01/03/2023]
Abstract
Besides the nerve endings, the soma of trigeminal neurons also respond to membrane depolarizations with the release of neurotransmitters and neuromodulators in the extracellular space within the ganglion, a process potentially important for the cross-communication between neighboring sensory neurons. In this study, we addressed the dependence of somatic release on Ca2+ influx in trigeminal neurons and the involvement of the different types of voltage-gated Ca2+ (Cav) channels in the process. Similar to the closely related dorsal root ganglion neurons, we found two kinetically distinct components of somatic release, a faster component stimulated by voltage but independent of the Ca2+ influx, and a slower component triggered by Ca2+ influx. The Ca2+ -dependent component was inhibited 80% by ω-conotoxin-MVIIC, an inhibitor of both N- and P/Q-type Cav channels, and 55% by the P/Q-type selective inhibitor ω-agatoxin-IVA. The selective L-type Ca2+ channel inhibitor nimodipine was instead without effect. These results suggest a major involvement of N- and P/Q-, but not L-type Cav channels in the somatic release of trigeminal neurons. Thus antinociceptive Cav channel antagonists acting on the N- and P/Q-type channels may exert their function by also modulating the somatic release and cross-communication between sensory neurons.
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Affiliation(s)
- Luigi Sforna
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Fabio Franciolini
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Luigi Catacuzzeno
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
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12
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Aguilera L, Bergmann FT, Dalmasso G, Elmas S, Elsässer T, Großeholz R, Holzheu P, Kalra P, Kummer U, Sahle S, Veith N. Robustness of frequency vs. amplitude coding of calcium oscillations during changing temperatures. Biophys Chem 2018; 245:17-24. [PMID: 30529877 DOI: 10.1016/j.bpc.2018.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 11/05/2018] [Accepted: 11/11/2018] [Indexed: 02/02/2023]
Abstract
Intracellular calcium oscillations have been widely studied. It is assumed that information is conveyed in the frequency, amplitude and shape of these oscillations. In particular, calcium signalling in mammalian liver cells has repeatedly been reported to display frequency coding so that an increasing amount of stimulus is translated into an increasing frequency of the oscillations. However, recently, we have shown that calcium oscillations in fish liver cells rather exhibit amplitude coding with increasing stimuli being translated into increasing amplitudes. Practical consequences of this difference are unknown so far. Here we investigated advantages and disadvantages of frequency vs. amplitude coding, in particular in environments with substantially changing temperatures (e.g. 10-20 degrees). For this purpose, we use computational modelling and a new approach to generate a calcium model exactly displaying a specific frequency and/or amplitude. We conclude that despite the advantages in flexibility that frequencies might offer for the transmission of information in the cell, amplitude coding is obviously more robust with respect to changes in environmental temperatures. This potentially explains the observed differences between two classes of organisms, one operating at constant temperatures whereas the other is not.
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Affiliation(s)
- Luis Aguilera
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
| | | | | | - Sinan Elmas
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
| | | | - Ruth Großeholz
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
| | - Pascal Holzheu
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
| | - Priyata Kalra
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
| | - Ursula Kummer
- BioQuant/COS, Heidelberg University, Heidelberg, Germany.
| | - Sven Sahle
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
| | - Nadine Veith
- BioQuant/COS, Heidelberg University, Heidelberg, Germany
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13
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Tyssowski KM, DeStefino NR, Cho JH, Dunn CJ, Poston RG, Carty CE, Jones RD, Chang SM, Romeo P, Wurzelmann MK, Ward JM, Andermann ML, Saha RN, Dudek SM, Gray JM. Different Neuronal Activity Patterns Induce Different Gene Expression Programs. Neuron 2018; 98:530-546.e11. [PMID: 29681534 PMCID: PMC5934296 DOI: 10.1016/j.neuron.2018.04.001] [Citation(s) in RCA: 208] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 02/20/2018] [Accepted: 03/29/2018] [Indexed: 12/22/2022]
Abstract
A vast number of different neuronal activity patterns could each induce a different set of activity-regulated genes. Mapping this coupling between activity pattern and gene induction would allow inference of a neuron's activity-pattern history from its gene expression and improve our understanding of activity-pattern-dependent synaptic plasticity. In genome-scale experiments comparing brief and sustained activity patterns, we reveal that activity-duration history can be inferred from gene expression profiles. Brief activity selectively induces a small subset of the activity-regulated gene program that corresponds to the first of three temporal waves of genes induced by sustained activity. Induction of these first-wave genes is mechanistically distinct from that of the later waves because it requires MAPK/ERK signaling but does not require de novo translation. Thus, the same mechanisms that establish the multi-wave temporal structure of gene induction also enable different gene sets to be induced by different activity durations.
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Affiliation(s)
| | | | - Jin-Hyung Cho
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Carissa J Dunn
- Molecular Cell Biology Unit, University of California Merced, Merced, CA 95343, USA
| | - Robert G Poston
- Molecular Cell Biology Unit, University of California Merced, Merced, CA 95343, USA
| | - Crista E Carty
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Richard D Jones
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Sarah M Chang
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Palmyra Romeo
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Mary K Wurzelmann
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - James M Ward
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Mark L Andermann
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Ramendra N Saha
- Molecular Cell Biology Unit, University of California Merced, Merced, CA 95343, USA; Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
| | - Jesse M Gray
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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14
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Regulated transport of signaling proteins from synapse to nucleus. Curr Opin Neurobiol 2017; 45:78-84. [PMID: 28502891 DOI: 10.1016/j.conb.2017.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/17/2017] [Indexed: 02/08/2023]
Abstract
Synapse-to-nucleus communication is essential for neural development, plasticity, and repair. In addition to fast electrochemical signaling, neurons employ a slower mechanism of protein transport from synapse-to-nucleus. This mechanism provides potential advantages, including the encoding of spatial information. Many synaptonuclear signaling proteins are transported from the postsynaptic compartment to the nucleus in an activity-dependent manner. The phosphorylation state of two such proteins, CRTC1 and Jacob, is dependent on the stimulus type. While most studies have focused on postsynaptic synaptonuclear communication, a transcriptional co-repressor, CtBP1, was recently discovered to undergo activity-dependent translocation from the presynaptic compartment to the nucleus. Recent evidence indicates that synapse-to-nucleus communication could be cell type-specific, including the identification of a distinct mechanism of excitation-transcription coupling in inhibitory neurons.
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15
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Gene networks activated by specific patterns of action potentials in dorsal root ganglia neurons. Sci Rep 2017; 7:43765. [PMID: 28256583 PMCID: PMC5335607 DOI: 10.1038/srep43765] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/23/2017] [Indexed: 12/17/2022] Open
Abstract
Gene regulatory networks underlie the long-term changes in cell specification, growth of synaptic connections, and adaptation that occur throughout neonatal and postnatal life. Here we show that the transcriptional response in neurons is exquisitely sensitive to the temporal nature of action potential firing patterns. Neurons were electrically stimulated with the same number of action potentials, but with different inter-burst intervals. We found that these subtle alterations in the timing of action potential firing differentially regulates hundreds of genes, across many functional categories, through the activation or repression of distinct transcriptional networks. Our results demonstrate that the transcriptional response in neurons to environmental stimuli, coded in the pattern of action potential firing, can be very sensitive to the temporal nature of action potential delivery rather than the intensity of stimulation or the total number of action potentials delivered. These data identify temporal kinetics of action potential firing as critical components regulating intracellular signalling pathways and gene expression in neurons to extracellular cues during early development and throughout life.
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16
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Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII) has emerged as key enzyme in many cardiac pathologies, especially heart failure (HF), myocardial infarction and cardiomyopathies, thus leading to contractile dysfunction and malignant arrhythmias. While many pathways leading to CaMKII activation have been elucidated in recent years, hardly any clinically viable compounds affecting CaMKII activity have progressed from basic in vitro science to in vivo studies. This review focuses on recent advances in anti-arrhythmic strategies involving CaMKII. Specifically, both inhibition of CaMKII itself to prevent arrhythmias, as well as anti-arrhythmic approaches affecting CaMKII activity via alterations in signaling cascades upstream and downstream of CaMKII will be discussed.
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Affiliation(s)
- Julian Mustroph
- Universitäres Herzzentrum Regensburg, Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
| | - Stefan Neef
- Universitäres Herzzentrum Regensburg, Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
| | - Lars S Maier
- Universitäres Herzzentrum Regensburg, Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany.
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17
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Scheitlin CG, Julian JA, Shanmughapriya S, Madesh M, Tsoukias NM, Alevriadou BR. Endothelial mitochondria regulate the intracellular Ca2+ response to fluid shear stress. Am J Physiol Cell Physiol 2016; 310:C479-90. [PMID: 26739489 DOI: 10.1152/ajpcell.00171.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 01/04/2016] [Indexed: 02/04/2023]
Abstract
Shear stress is known to stimulate an intracellular free calcium concentration ([Ca(2+)]i) response in vascular endothelial cells (ECs). [Ca(2+)]i is a key second messenger for signaling that leads to vasodilation and EC survival. Although it is accepted that the shear-induced [Ca(2+)]i response is, in part, due to Ca(2+) release from the endoplasmic reticulum (ER), the role of mitochondria (second largest Ca(2+) store) is unknown. We hypothesized that the mitochondria play a role in regulating [Ca(2+)]i in sheared ECs. Cultured ECs, loaded with a Ca(2+)-sensitive fluorophore, were exposed to physiological levels of shear stress. Shear stress elicited [Ca(2+)]i transients in a percentage of cells with a fraction of them displaying oscillations. Peak magnitudes, percentage of oscillating ECs, and oscillation frequencies depended on the shear level. [Ca(2+)]i transients/oscillations were present when experiments were conducted in Ca(2+)-free solution (plus lanthanum) but absent when ECs were treated with a phospholipase C inhibitor, suggesting that the ER inositol 1,4,5-trisphosphate receptor is responsible for the [Ca(2+)]i response. Either a mitochondrial uncoupler or an electron transport chain inhibitor, but not a mitochondrial ATP synthase inhibitor, prevented the occurrence of transients and especially inhibited the oscillations. Knockdown of the mitochondrial Ca(2+) uniporter also inhibited the shear-induced [Ca(2+)]i transients/oscillations compared with controls. Hence, EC mitochondria, through Ca(2+) uptake/release, regulate the temporal profile of shear-induced ER Ca(2+) release. [Ca(2+)]i oscillation frequencies detected were within the range for activation of mechanoresponsive kinases and transcription factors, suggesting that dysfunctional EC mitochondria may contribute to cardiovascular disease by deregulating the shear-induced [Ca(2+)]i response.
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Affiliation(s)
- Christopher G Scheitlin
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Justin A Julian
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - B Rita Alevriadou
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio;
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18
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Differential CaMKII regulation by voltage-gated calcium channels in the striatum. Mol Cell Neurosci 2015; 68:234-43. [PMID: 26255006 DOI: 10.1016/j.mcn.2015.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/06/2015] [Accepted: 08/03/2015] [Indexed: 01/21/2023] Open
Abstract
Calcium signaling regulates synaptic plasticity and many other functions in striatal medium spiny neurons to modulate basal ganglia function. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a major calcium-dependent signaling protein that couples calcium entry to diverse cellular changes. CaMKII activation results in autophosphorylation at Thr286 and sustained calcium-independent CaMKII activity after calcium signals dissipate. However, little is known about the mechanisms regulating striatal CaMKII. To address this, mouse brain slices were treated with pharmacological modulators of calcium channels and punches of dorsal striatum were immunoblotted for CaMKII Thr286 autophosphorylation as an index of CaMKII activation. KCl depolarization increased levels of CaMKII autophosphorylation ~2-fold; this increase was blocked by an LTCC antagonist and was mimicked by treatment with pharmacological LTCC activators. The chelation of extracellular calcium robustly decreased basal CaMKII autophosphorylation within 5min and increased levels of total CaMKII in cytosolic fractions, in addition to decreasing the phosphorylation of CaMKII sites in the GluN2B subunit of NMDA receptors and the GluA1 subunit of AMPA receptors. We also found that the maintenance of basal levels of CaMKII autophosphorylation requires low-voltage gated T-type calcium channels, but not LTCCs or R-type calcium channels. Our findings indicate that CaMKII activity is dynamically regulated by multiple calcium channels in the striatum thus coupling calcium entry to key downstream substrates.
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19
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Toussaint F, Charbel C, Blanchette A, Ledoux J. CaMKII regulates intracellular Ca²⁺ dynamics in native endothelial cells. Cell Calcium 2015; 58:275-85. [PMID: 26100947 DOI: 10.1016/j.ceca.2015.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 05/15/2015] [Accepted: 06/06/2015] [Indexed: 01/11/2023]
Abstract
Localized endothelial Ca(2+) signalling, such as Ca(2+) pulsars, can modulate the contractile state of the underlying vascular smooth muscle cell through specific endothelial targets. In addition to K(Ca)3.1 as a target, Ca(2+) pulsars, an IP3R-dependent pulsatile Ca(2+) release from the endoplasmic reticulum (ER) could activate a frequency-sensitive Ca(2+)-dependent kinase such as CaMKII. In the absence of extracellular Ca(2+), acetylcholine increased endothelial CaMKII phosphorylation and activation, thereby suggesting CaMKII activation independently of Ca(2+) influx. Herein, a reciprocal relation where CaMKII controls endothelial Ca(2+) dynamics has been investigated in mesenteric arteries. Both CaMKIIα and β isoforms have been identified in endothelial cells and close proximity (<40 nm) suggests their association in heteromultimers. Intracellular Ca(2+) monitoring with high speed confocal microscopy then showed that inhibition of CaMKII with KN-93 significantly increased the population of Ca(2+) pulsars active sites (+89%), suggesting CaMKII as a major regulator of Ca(2+) pulsars in native endothelium. Mechanistic insights were then sought through the elucidation of the impact of CaMKII on ER Ca(2+) store. ER Ca(2+) emptying was accelerated by CaMKII inhibition and ER Ca(2+) content was assessed using ionomycin. Exposure to KN-93 strongly diminished ER Ca(2+) content (-61%) by relieving CaMKII-dependent inhibition of IP3 receptors (IP3R). Moreover, in situ proximity ligation assay suggested CaMKII-IP3R promiscuity, essential condition for a protein-protein interaction. Interestingly, segregation of IP3R within myoendothelial projection (MEP) appears to be isoform-specific. Hence, only IP3R type 1 and type 2 are detected within fenestrations of the internal elastic lamina, sites of MEP, whilst type 3 is absent from these structures. In summary, CaMKII seems to act as a Ca(2+)-sensitive switch of a negative feedback loop regulating endothelial Ca(2+) homeostasis, including Ca(2+) pulsars.
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Affiliation(s)
- Fanny Toussaint
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada; Department of Physiology, Université de Montréal, Québec, Canada
| | - Chimène Charbel
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada; Department of Pharmacology, Université de Montréal, Québec, Canada
| | | | - Jonathan Ledoux
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada; Department of Physiology, Université de Montréal, Québec, Canada; Department of Pharmacology, Université de Montréal, Québec, Canada; Department of Medicine, Université de Montréal, Québec, Canada.
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20
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Differential expression of CaMKII isoforms and overall kinase activity in rat dorsal root ganglia after injury. Neuroscience 2015; 300:116-27. [PMID: 25982557 DOI: 10.1016/j.neuroscience.2015.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/01/2015] [Accepted: 05/06/2015] [Indexed: 11/21/2022]
Abstract
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) decodes neuronal activity by translating cytoplasmic Ca(2+) signals into kinase activity that regulates neuronal functions including excitability, gene expression, and synaptic transmission. Four genes lead to developmental and differential expression of CaMKII isoforms (α, β, γ, δ). We determined mRNA levels of these isoforms in the dorsal root ganglia (DRG) of adult rats with and without nerve injury in order to determine if differential expression of CaMKII isoforms may contribute to functional differences that follow injury. DRG neurons express mRNA for all four isoforms, and the relative abundance of CaMKII isoforms was γ>α>β=δ, based on the CT values. Following ligation of the 5th lumbar (L5) spinal nerve (SNL), the β isoform did not change, but mRNA levels of both the γ and α isoforms were reduced in the directly injured L5 neurons, and the α isoform was reduced in L4 neurons, compared to their contemporary controls. In contrast, expression of the δ isoform mRNA increased in L5 neurons. CaMKII protein decreased following nerve injury in both L4 and L5 populations. Total CaMKII activity measured under saturating Ca(2+)/CaM conditions was decreased in both L4 and L5 populations, while autonomous CaMKII activity determined in the absence of Ca(2+) was selectively reduced in axotomized L5 neurons 21days after injury. Thus, loss of CaMKII signaling in sensory neurons after peripheral nerve injury may contribute to neuronal dysfunction and pain.
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21
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Liu GS, Morales A, Vafiadaki E, Lam CK, Cai WF, Haghighi K, Adly G, Hershberger RE, Kranias EG. A novel human R25C-phospholamban mutation is associated with super-inhibition of calcium cycling and ventricular arrhythmia. Cardiovasc Res 2015; 107:164-74. [PMID: 25852082 DOI: 10.1093/cvr/cvv127] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/20/2015] [Indexed: 12/26/2022] Open
Abstract
AIMS Depressed sarcoplasmic reticulum (SR) Ca(2+) cycling, a universal characteristic of human and experimental heart failure, may be associated with genetic alterations in key Ca(2+)-handling proteins. In this study, we identified a novel PLN mutation (R25C) in dilated cardiomyopathy (DCM) and investigated its functional significance in cardiomyocyte Ca(2+)-handling and contractility. METHODS AND RESULTS Exome sequencing identified a C73T substitution in the coding region of PLN in a family with DCM. The four heterozygous family members had implantable cardiac defibrillators, and three developed prominent ventricular arrhythmias. Overexpression of R25C-PLN in adult rat cardiomyocytes significantly suppressed the Ca(2+) affinity of SR Ca(2+)-ATPase (SERCA2a), resulting in decreased SR Ca(2+) content, Ca(2+) transients, and impaired contractile function, compared with WT-PLN. These inhibitory effects were associated with enhanced interaction of R25C-PLN with SERCA2, which was prevented by PKA phosphorylation. Accordingly, isoproterenol stimulation relieved the depressive effects of R25C-PLN in cardiomyocytes. However, R25C-PLN also elicited increases in the frequency of Ca(2+) sparks and waves as well as stress-induced aftercontractions. This was accompanied by increased Ca(2+)/calmodulin-dependent protein kinase II activity and hyper-phosphorylation of RyR2 at serine 2814. CONCLUSION The findings demonstrate that human R25C-PLN is associated with super-inhibition of SERCA2a and Ca(2+) transport as well as increased SR Ca(2+) leak, promoting arrhythmogenesis under stress conditions. This is the first mechanistic evidence that increased PLN inhibition may impact both SR Ca(2+) uptake and Ca(2+) release activities and suggests that the human R25C-PLN may be a prognostic factor for increased ventricular arrhythmia risk in DCM carriers.
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Affiliation(s)
- Guan-Sheng Liu
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Ana Morales
- Division of Human Genetics, Ohio State University College of Medicine, Columbus, OH, USA Dorothy M. Davis Heart and Lung Research Institute, Ohio State University College of Medicine, Columbus, OH 45267-0575, USA
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece
| | - Chi Keung Lam
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Wen-Feng Cai
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - George Adly
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Ray E Hershberger
- Division of Human Genetics, Ohio State University College of Medicine, Columbus, OH, USA Dorothy M. Davis Heart and Lung Research Institute, Ohio State University College of Medicine, Columbus, OH 45267-0575, USA Division of Cardiovascular Medicine, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, PO Box 670575, 231 Albert Sabin Way, Cincinnati, OH, USA Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Greece
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22
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Genetic Dissection of the Physiological Role of Skeletal Muscle in Metabolic Syndrome. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/635146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The primary deficiency underlying metabolic syndrome is insulin resistance, in which insulin-responsive peripheral tissues fail to maintain glucose homeostasis. Because skeletal muscle is the major site for insulin-induced glucose uptake, impairments in skeletal muscle’s insulin responsiveness play a major role in the development of insulin resistance and type 2 diabetes. For example, skeletal muscle of type 2 diabetes patients and their offspring exhibit reduced ratios of slow oxidative muscle. These observations suggest the possibility of applying muscle remodeling to recover insulin sensitivity in metabolic syndrome. Skeletal muscle is highly adaptive to external stimulations such as exercise; however, in practice it is often not practical or possible to enforce the necessary intensity to obtain measurable benefits to the metabolic syndrome patient population. Therefore, identifying molecular targets for inducing muscle remodeling would provide new approaches to treat metabolic syndrome. In this review, the physiological properties of skeletal muscle, genetic analysis of metabolic syndrome in human populations and model organisms, and genetically engineered mouse models will be discussed in regard to the prospect of applying skeletal muscle remodeling as possible therapy for metabolic syndrome.
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23
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Frequency decoding of calcium oscillations. Biochim Biophys Acta Gen Subj 2014; 1840:964-9. [DOI: 10.1016/j.bbagen.2013.11.015] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/27/2013] [Accepted: 11/15/2013] [Indexed: 01/14/2023]
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24
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Jelicic Kadic A, Boric M, Kostic S, Sapunar D, Puljak L. The effects of intraganglionic injection of calcium/calmodulin-dependent protein kinase II inhibitors on pain-related behavior in diabetic neuropathy. Neuroscience 2014; 256:302-8. [DOI: 10.1016/j.neuroscience.2013.10.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/16/2013] [Accepted: 10/14/2013] [Indexed: 11/24/2022]
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25
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Saha RN, Dudek SM. Splitting hares and tortoises: a classification of neuronal immediate early gene transcription based on poised RNA polymerase II. Neuroscience 2013; 247:175-81. [PMID: 23711585 PMCID: PMC3722259 DOI: 10.1016/j.neuroscience.2013.04.064] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 04/19/2013] [Accepted: 04/20/2013] [Indexed: 01/06/2023]
Abstract
Immediate early transcription is an integral part of the neuronal response to environmental stimulation and serves many brain processes including development, learning, triggers of programmed cell death, and reaction to injury and drugs. Following a stimulus, neurons express a select few genes within a short period of time without undergoing de novo protein translation. Referred to as the 'gateway to genetic response', these immediate early genes (IEGs) are either expressed within a few minutes of stimulation or later within the hour. In neuronal IEGs that are expressed rapidly, productive elongation in response to neuronal activity is jump-started by constitutive transcription initiation together with RNA polymerase II stalling in the vicinity of the promoter. IEGs expressed later in the hour do not depend on this mechanism. On the basis of this Polymerase II poising, we propose that the immediate early genes can be grouped in two distinct classes: the rapid and the delayed IEGs. The possible biological relevance of these classes in neurons is discussed.
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Affiliation(s)
- R N Saha
- Synaptic and Developmental Plasticity Group, Laboratory of Neurobiology, NIEHS, NIH, 111 TW Alexander Drive, Research Triangle Park, NC 27709, United States
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26
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Ferhatovic L, Banozic A, Kostic S, Sapunar D, Puljak L. Sex differences in pain-related behavior and expression of calcium/calmodulin-dependent protein kinase II in dorsal root ganglia of rats with diabetes type 1 and type 2. Acta Histochem 2013; 115:496-504. [PMID: 23267764 DOI: 10.1016/j.acthis.2012.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/08/2012] [Accepted: 11/12/2012] [Indexed: 01/23/2023]
Abstract
Sex differences in pain-related behavior and expression of calcium/calmodulin dependent protein kinase II (CaMKII) in dorsal root ganglia were studied in rat models of Diabetes mellitus type 1 (DM1) and type 2 (DM2). DM1 was induced with 55mg/kg streptozotocin, and DM2 with a combination of high-fat diet and 35mg/kg of streptozotocin. Pain-related behavior was analyzed using thermal and mechanical stimuli. The expression of CaMKII was analyzed with immunofluorescence. Sexual dimorphism in glycemia, and expression of CaMKII was observed in the rat model of DM1, but not in DM2 animals. Increased expression of total CaMKII (tCaMKII) in small-diameter dorsal root ganglia neurons, which are associated with nociception, was found only in male DM1 rats. None of the animals showed increased expression of the phosphorylated alpha CaMKII isoform in small-diameter neurons. The expression of gamma and delta isoforms of CaMKII remained unchanged in all analyzed animal groups. Different patterns of glycemia and tCaMKII expression in male and female model of DM1 were not associated with sexual dimorphism in pain-related behavior. The present findings do not suggest sex-related differences in diabetic painful peripheral neuropathy in male and female diabetic rats.
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MESH Headings
- Animals
- Behavior, Animal
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 1/enzymology
- Diabetes Mellitus, Type 1/physiopathology
- Diabetes Mellitus, Type 2/enzymology
- Diabetes Mellitus, Type 2/physiopathology
- Disease Models, Animal
- Female
- Ganglia, Spinal/enzymology
- Ganglia, Spinal/physiopathology
- Hyperglycemia/enzymology
- Hyperglycemia/physiopathology
- Male
- Pain/enzymology
- Pain/physiopathology
- Rats
- Rats, Sprague-Dawley
- Sex Factors
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Affiliation(s)
- Lejla Ferhatovic
- Laboratory for Pain Research, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia.
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Stratton MM, Chao LH, Schulman H, Kuriyan J. Structural studies on the regulation of Ca2+/calmodulin dependent protein kinase II. Curr Opin Struct Biol 2013; 23:292-301. [PMID: 23632248 DOI: 10.1016/j.sbi.2013.04.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/24/2013] [Accepted: 04/02/2013] [Indexed: 11/15/2022]
Abstract
Ca(2+)/calmodulin dependent protein kinase II (CaMKII) is a broadly distributed metazoan Ser/Thr protein kinase that is important in neuronal and cardiac signaling. CaMKII forms oligomeric assemblies, typically dodecameric, in which the calcium-responsive kinase domains are organized around a central hub. We review the results of crystallographic analyses of CaMKII, including the recently determined structure of a full-length and autoinhibited form of the holoenzyme. These structures, when combined with other data, allow informed speculation about how CaMKII escapes calcium-dependence when calcium spikes exceed threshold frequencies.
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Affiliation(s)
- Margaret M Stratton
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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Qian A, Song D, Li Y, Liu X, Tang D, Yao W, Yuan Y. Role of voltage gated Ca2+ channels in rat visceral hypersensitivity change induced by 2,4,6-trinitrobenzene sulfonic acid. Mol Pain 2013; 9:15. [PMID: 23537331 PMCID: PMC3626538 DOI: 10.1186/1744-8069-9-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 03/22/2013] [Indexed: 11/10/2022] Open
Abstract
Background Visceral pain is common symptom involved in many gastrointestinal disorders such as inflammatory bowel disease. The underlying molecular mechanisms remain elusive. We investigated the molecular mechanisms and the role for voltage gated calcium channel (VGCC) in the pathogenesis in a rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced visceral inflammatory hypersensitivity. Results Using Agilent cDNA arrays, we found 172 genes changed significantly in dorsal root ganglia (DRG) of TNBS treated rats. Among these changed genes, Cav1.2 and Cav2.3 were significantly up-regulated. Then the RT-PCR and Western blot further confirmed the up-regulation of Cav1.2 and Cav2.3. The whole cell patch clamp recording of acutely dissociated colonic specific DRG neurons showed that the peak IBa density was significantly increased in colonic neurons of TNBS treated rats compared with control rats (−127.82 ± 20.82 pA/pF Vs −91.67 ± 19.02 pA/pF, n = 9, *P < 0.05). To distinguish the different type of calcium currents with the corresponding selective channel blockers, we found that L-type (−38.56 ± 3.97 pA/pF Vs −25.75 ± 3.35 pA/pF, n = 9, * P < 0.05) and R-type (−13.31 ± 1.36 pA/pF Vs −8.60 ± 1.25 pA/pF, n = 9, * P < 0.05) calcium current density were significantly increased in colonic DRG neurons of TNBS treated rats compared with control rats. In addition, pharmacological blockade with L-type antagonist (nimodipine) and R-type antagonist (SNX-482) with intrathecal injection attenuates visceral pain in TNBS induced inflammatory visceral hypersensitivity. Conclusion Cav1.2 and Cav2.3 in colonic primary sensory neurons play an important role in visceral inflammatory hyperalgesia, which maybe the potential therapeutic targets.
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Affiliation(s)
- Aihua Qian
- Department of Gastroenterology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
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Ferhatovic L, Banozic A, Kostic S, Kurir TT, Novak A, Vrdoljak L, Heffer M, Sapunar D, Puljak L. Expression of Calcium/Calmodulin-Dependent Protein Kinase II and Pain-Related Behavior in Rat Models of Type 1 and Type 2 Diabetes. Anesth Analg 2013; 116:712-21. [DOI: 10.1213/ane.0b013e318279b540] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Matamales M. Neuronal activity-regulated gene transcription: how are distant synaptic signals conveyed to the nucleus? F1000Res 2012; 1:69. [PMID: 24327840 PMCID: PMC3752646 DOI: 10.12688/f1000research.1-69.v1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/04/2012] [Indexed: 01/01/2023] Open
Abstract
Synaptic activity can trigger gene expression programs that are required for the stable change of neuronal properties, a process that is essential for learning and memory. Currently, it is still unclear how the stimulation of dendritic synapses can be coupled to transcription in the nucleus in a timely way given that large distances can separate these two cellular compartments. Although several mechanisms have been proposed to explain long distance communication between synapses and the nucleus, the possible co-existence of these models and their relevance in physiological conditions remain elusive. One model suggests that synaptic activation triggers the translocation to the nucleus of certain transcription regulators localised at postsynaptic sites that function as synapto-nuclear messengers. Alternatively, it has been hypothesised that synaptic activity initiates propagating regenerative intracellular calcium waves that spread through dendrites into the nucleus where nuclear transcription machinery is thereby regulated. It has also been postulated that membrane depolarisation of voltage-gated calcium channels on the somatic membrane is sufficient to increase intracellular calcium concentration and activate transcription without the need for transported signals from distant synapses. Here I provide a critical overview of the suggested mechanisms for coupling synaptic stimulation to transcription, the underlying assumptions behind them and their plausible physiological significance.
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Affiliation(s)
- Miriam Matamales
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
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Mironov SL. Calmodulin and calmodulin kinase II mediate emergent bursting activity in the brainstem respiratory network (preBötzinger complex). J Physiol 2012. [PMID: 23207595 DOI: 10.1113/jphysiol.2012.237362] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Emergence of persistent activity in networks can be controlled by intracellular signalling pathways but the mechanisms involved and their role are not yet fully explored. Using calcium imaging and patch-clamp we examined the rhythmic activity in the preBötzinger complex (preBötC) in the lower brainstem that generates the respiratory motor output. In functionally intact acute slices brief hypoxia, electrical stimulation and activation of AMPA receptors transiently depressed bursting activity which then recovered with augmentation. The effects were abrogated after chelation of intracellular calcium, blockade of L-type calcium channels and inhibition of calmodulin (CaM) and CaM kinase (CaMKII). Rhythmic calcium transients and synaptic drive currents in preBötC neurons in the organotypic slices showed similar CaM- and CaMKII-dependent responses. The stimuli increased the amplitude of spontaneous and miniature excitatory synaptic currents indicating postsynaptic changes at glutamatergic synapses. In the acute and organotypic slices, CaM stimulated and ADP inhibited calcium-dependent TRPM4 channels and CaMKII augmented synaptic drive currents. Experimental data and simulations show the role of ADP and CaMKII in the control of bursting activity and its relation to intracellular signalling. I propose that CaMKII-mediated facilitation of glutamatergic transmission strengthens emergent synchronous activity within preBötC that is then maintained by periodic surges of calcium during the bursts. This may find implications in restoration and consolidation of autonomous activity in the respiratory disorders.
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Affiliation(s)
- S L Mironov
- Department of Neuro- and Sensory Physiology, Georg-August-University, Humboldtallee 23, 37073 Göttingen, Germany.
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Zhu Y, Lu S, Gold MS. Persistent inflammation increases GABA-induced depolarization of rat cutaneous dorsal root ganglion neurons in vitro. Neuroscience 2012; 220:330-40. [PMID: 22728089 PMCID: PMC3412885 DOI: 10.1016/j.neuroscience.2012.06.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/07/2012] [Accepted: 06/09/2012] [Indexed: 11/18/2022]
Abstract
Persistent inflammation is associated with a shift in spinal GABA(A) signaling from inhibition to excitation such that GABA(A)-receptor activation contributes to inflammatory hyperalgesia. We tested the hypothesis that the primary afferent is the site of the persistent inflammation-induced shift in GABA(A) signaling which is due to a Na(+)-K(+)-Cl(-)-co-transporter (NKCC1)-dependent depolarization of the GABA(A) current equilibrium potential (E(GABA)). Acutely dissociated retrogradely labeled cutaneous dorsal root ganglion (DRG) neurons from naïve and inflamed (3 days after a subcutaneous injection of complete Freund's adjuvant) adult male rats were studied with Ca(2+) imaging, western blot and gramicidin-perforated patch recording. GABA evoked a Ca(2+) transient in a subpopulation of small- to medium-diameter capsaicin-sensitive cutaneous neurons. Inflammation was associated with a significant increase in the magnitude of GABA-induced depolarization as well as the percentage of neurons in which GABA evoked a Ca(2+) transient. There was no detectable change in NKCC1 protein or phosphoprotein at the whole ganglia level. Furthermore, the increase in excitatory response was comparable in both HEPES- and HCO(3)(-)-buffered solutions, but was only associated with a depolarization of E(GABA) in HCO(3)(-)-based solution. In contrast, under both recording conditions, the excitatory response was associated with an increase in GABA(A) current density, a decrease in low threshold K(+) current density, and resting membrane potential depolarization. Our results suggest that increasing K(+) conductance in afferents innervating a site of persistent inflammation may have greater efficacy in the inhibition of inflammatory hyperalgesia than attempting to drive a hyperpolarizing shift in E(GABA).
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Affiliation(s)
- Yi Zhu
- Dept of Neural and Pain Sciences, University of Maryland, Baltimore School of Dentistry, Baltimore, Maryland
- Dept of Anesthesiology, University of Pittsburgh, Pittsburgh, USA
| | - Shaogang Lu
- Dept of Medicine (Division of Gastroenterology Hepatology and Nutrition), University of Pittsburgh, Pittsburgh, USA
| | - Michael S. Gold
- Dept of Anesthesiology, University of Pittsburgh, Pittsburgh, USA
- Dept of Neurobiology, University of Pittsburgh, Pittsburgh, USA
- Dept of Medicine (Division of Gastroenterology Hepatology and Nutrition), University of Pittsburgh, Pittsburgh, USA
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, USA
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, USA
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Lasko J, Schlingmann K, Klocke A, Mengel GA, Turner R. Calcium/calmodulin and cAMP/protein kinase-A pathways regulate sperm motility in the stallion. Anim Reprod Sci 2012; 132:169-77. [PMID: 22687341 DOI: 10.1016/j.anireprosci.2012.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 05/10/2012] [Accepted: 05/16/2012] [Indexed: 01/01/2023]
Abstract
In spite of the importance of sperm motility to fertility in the stallion, little is known about the signaling pathways that regulate motility in this species. In other mammals, calcium/calmodulin signaling and the cyclic AMP/protein kinase-A pathway are involved in sperm motility regulation. We hypothesized that these pathways also were involved in the regulation of sperm motility in the stallion. Using immunoblotting, calmodulin and the calmodulin-dependent protein kinase II β were shown to be present in stallion sperm and with indirect immunofluorescence calmodulin was localized to the acrosome and flagellar principal piece. Additionally, inhibition of either calmodulin or protein kinase-A significantly reduced sperm motility without affecting viability. Following inhibition of calmodulin, motility was not restored with agonists of the cyclic AMP/protein kinase-A pathway. These data suggest that calcium/calmodulin and cyclic AMP/protein kinase-A pathways are involved in the regulation of stallion sperm motility. The failure of cyclic AMP/protein kinase-A agonists to restore motility of calmodulin inhibited sperm suggests that both pathways may be required to support normal motility.
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Affiliation(s)
- Jodi Lasko
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, 382 West Street Rd., Kennett Square, PA 19348, USA
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Abstract
For many years it has been assumed that the identity of the transmitters expressed by neurons is stable and unchanging. Recent work, however, shows that electrical activity can respecify neurotransmitter expression during development and in the mature nervous system, and an understanding is emerging of the molecular mechanisms underlying activity-dependent transmitter respecification. Changes in postsynaptic neurotransmitter receptor expression accompany and match changes in transmitter specification, thus enabling synaptic transmission. The functional roles of neurotransmitter respecification are beginning to be understood and appear to involve homeostatic synaptic regulation, which in turn influences behaviour. Activation of this novel form of plasticity by sensorimotor stimuli may provide clinical benefits.
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Kojundzic SL, Puljak L, Hogan Q, Sapunar D. Depression of Ca(2+)/calmodulin-dependent protein kinase II in dorsal root ganglion neurons after spinal nerve ligation. J Comp Neurol 2010; 518:64-74. [PMID: 19882720 DOI: 10.1002/cne.22209] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The enzyme calcium/calmodulin-dependent protein kinase II (CaMKII) is associated with memory and its alpha isoform is critical for development of activity-induced synaptic changes. Therefore, we hypothesized that CaMKII is involved in altered function of dorsal root ganglion (DRG) neurons after neuronal injury. To test this hypothesis, Sprague-Dawley rats were made hyperalgesic by L5 and L6 spinal nerve ligation (SNL), and changes in total phosphorylated and unphosphorylated CaMKII (tCaMKII) and phosphorylated form of its alpha isoform (pCaMKIIalpha) were analyzed using immunochemistry in different subpopulations of DRG. SNL did not induce any changes in tCaMKII between experimental groups, while the overall percentage of pCaMKIIalpha-positive neurons in injured L5 DRG SNL (24.8%) decreased significantly when compared to control (41.7%). SNL did not change the percentage of pCaMKIIalpha/N52 colabeled neurons but decreased the percentage of N52-negative nonmyelinated neurons that expressed pCaMKIIalpha from 27% in control animals to 11% after axotomy. We also observed a significant decrease in the percentage of small nonpeptidergic neurons labeled with IB4 (37.6% in control vs. 4.0% in L5 SNL DRG), as well as a decrease in the percentage of pCaMKIIalpha/IB4 colabeled neurons in injured L5 DRGs (27% in control vs. 1% in L5 DRG of SNL group). Our results show that reduction in pCaMKIIalpha levels following peripheral injury is due to the loss of IB4-positive neurons. These results indicate that diminished afferent activity after axotomy may lead to decreased phosphorylation of CaMKIIalpha.
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Affiliation(s)
- Sanja Lovric Kojundzic
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia
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Sustained depolarization decreases calcium/calmodulin-dependent protein kinase II activity and gene expression in dopamine neurons. Neuroscience 2009; 163:277-85. [DOI: 10.1016/j.neuroscience.2009.06.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 06/15/2009] [Accepted: 06/17/2009] [Indexed: 11/24/2022]
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Suppressed Ca2+/CaM/CaMKII-dependent K(ATP) channel activity in primary afferent neurons mediates hyperalgesia after axotomy. Proc Natl Acad Sci U S A 2009; 106:8725-30. [PMID: 19439665 DOI: 10.1073/pnas.0901815106] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Painful axotomy decreases K(ATP) channel current (IK(ATP)) in primary afferent neurons. Because cytosolic Ca(2+) signaling is depressed in injured dorsal root ganglia (DRG) neurons, we investigated whether Ca(2+)-calmodulin (CaM)-Ca(2+)/CaM-dependent kinase II (CaMKII) regulates IK(ATP) in large DRG neurons. Immunohistochemistry identified the presence of K(ATP) channel subunits SUR1, SUR2, and Kir6.2 but not Kir6.1, and pCaMKII in neurofilament 200-positive DRG somata. Single-channel recordings from cell-attached patches revealed that basal and evoked IK(ATP) by ionomycin, a Ca(2+) ionophore, is activated by CaMKII. In axotomized neurons from rats made hyperalgesic by spinal nerve ligation (SNL), basal K(ATP) channel activity was decreased, and sensitivity to ionomycin was abolished. Basal and Ca(2+)-evoked K(ATP) channel activity correlated inversely with the degree of hyperalgesia induced by SNL in the rats from which the neurons were isolated. Inhibition of IK(ATP) by glybenclamide, a selective K(ATP) channel inhibitor, depolarized resting membrane potential (RMP) recorded in perforated whole-cell patches and enhanced neurotransmitter release measured by amperometry. The selective K(ATP) channel opener diazoxide hyperpolarized the RMP and attenuated neurotransmitter release. Axotomized neurons from rats made hyperalgesic by SNL lost sensitivity to the myristoylated form of autocamtide-2-related inhibitory peptide (AIPm), a pseudosubstrate blocker of CaMKII, whereas axotomized neurons from SNL animals that failed to develop hyperalgesia showed normal IK(ATP) inhibition by AIPm. AIPm also depolarized RMP in control neurons via K(ATP) channel inhibition. Unitary current conductance and sensitivity of K(ATP) channels to cytosolic ATP and ligands were preserved even after painful nerve injury, thus providing opportunities for selective therapeutic targeting against neuropathic pain.
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Abstract
The neuronal nucleus is now widely accepted as playing a vital role in maintaining long-term changes in synaptic effectiveness. To act, however, the nucleus must be appropriately relayed with information regarding the latest round of synaptic plasticity. Several constraints of doing so in a neuron pertain to the often significant spatial distance of synapses from the nucleus and the number of synapses required for such a signal to reach functional levels in the nucleus. Largely based on the sensitivity of transcriptional responses to NMDA receptor antagonists, it has been postulated that the signals are physically relayed by biochemical messengers from the synapse to the nucleus. Alternatively, a second, less often considered but equally viable method of signal transduction may be initiated by action potentials generated proximal to the nucleus, wherefrom the signal can be relayed directly by calcium or indirectly by biochemical second messengers. We consider action potential-dependent signaling to the nucleus to have its own computational advantages over the synapse-to-nucleus signal for some functions. This minireview summarizes the logic and experimental support for these two modes of signaling and attempts to validate the action potential model as playing an important role in transcriptional regulation relating specifically to long-term synaptic plasticity.
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Affiliation(s)
- Ramendra N Saha
- Laboratory of Neurobiology, National Institute of Environmental Health Services, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Lu SG, Gold MS. Inflammation-induced increase in evoked calcium transients in subpopulations of rat dorsal root ganglion neurons. Neuroscience 2008; 153:279-88. [PMID: 18367340 PMCID: PMC2396945 DOI: 10.1016/j.neuroscience.2008.02.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 01/21/2008] [Accepted: 02/05/2008] [Indexed: 12/21/2022]
Abstract
The concentration of intracellular Ca(2+) ([Ca(2+)](i)) influences neuronal properties ranging from excitability to neurotransmitter release. Persistent inflammation is associated with changes in the properties of primary afferent neurons ranging from excitability to transmitter release. The purpose of the present study was to determine whether previously described inflammation-induced changes in excitability and transmitter release are associated with changes in the regulation of [Ca(2+)](i). Acutely dissociated dorsal root ganglion (DRG) neurons harvested from adult rats 3 days following a hind-paw injection of complete Freund's adjuvant (CFA) or naïve controls, were stimulated with 30 mM K(+) (High K(+)). High K(+) evoked changes in [Ca(2+)](i) were assessed with fura-2 ratiometric microfluorimetry. Subpopulations of DRG neurons were defined by cell body diameter, isolectin B4 (IB4) binding, capsaicin (CAP) sensitivity and target of innervation (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbo-cyanine perchlorate labeling). Inflammation was associated with significant increases in resting [Ca(2+)](i) and increases in the magnitude and decreases in the decay, of the evoked increase in [Ca(2+)](i). The changes in evoked transients were larger in neurons innervating the site of inflammation. Furthermore, there were differences among subpopulations of DRG neurons with respect to changes in magnitude and/or decay of the evoked transient such that the increase in magnitude was larger in small- and medium-diameter neurons than in large diameter neurons while the decrease in the decay was greater in CAP responsive, IB4 positive, small- and medium-diameter neurons than in CAP unresponsive, IB4 negative and/or large-diameter neurons. These changes in the regulation of [Ca(2+)](i) were not due to inflammation-induced changes in passive or active electrophysiological properties. Importantly, an inflammation-induced increase in evoked Ca(2+) transients in putative nociceptive afferents may contribute to the pain and hyperalgesia associated with persistent inflammation via facilitation of transmitter release from these afferents.
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Affiliation(s)
- Shao-Gang Lu
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh, Pittsburgh, PA 15213
| | - Michael S. Gold
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh, Pittsburgh, PA 15213
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213
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Abstract
Experimental studies have demonstrated that Ca(2+)-regulated proteins are sensitive to the frequency of Ca(2+) oscillations, and several mathematical models for specific proteins have provided insight into the mechanisms involved. Because of the large number of Ca(2+)-regulated proteins in signal transduction, metabolism and gene expression, it is desirable to establish in general terms which molecular properties shape the response to oscillatory Ca(2+) signals. Here we address this question by analyzing in detail a model of a prototypical Ca(2+)-decoding module, consisting of a target protein whose activity is controlled by a Ca(2+)-activated kinase and the counteracting phosphatase. We show that this module can decode the frequency of Ca(2+) oscillations, at constant average Ca(2+) signal, provided that the Ca(2+) spikes are narrow and the oscillation frequency is sufficiently low--of the order of the phosphatase rate constant or below. Moreover, Ca(2+) oscillations activate the target more efficiently than a constant signal when Ca(2+) is bound cooperatively and with low affinity. Thus, the rate constants and the Ca(2+) affinities of the target-modifying enzymes can be tuned in such a way that the module responds optimally to Ca(2+) spikes of a certain amplitude and frequency. Frequency sensitivity is further enhanced when the limited duration of the external stimulus driving Ca(2+) signaling is accounted for. Thus, our study identifies molecular parameters that may be involved in establishing the specificity of cellular responses downstream of Ca(2+) oscillations.
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Aydin J, Korhonen T, Tavi P, Allen DG, Westerblad H, Bruton JD. Activation of Ca(2+)-dependent protein kinase II during repeated contractions in single muscle fibres from mouse is dependent on the frequency of sarcoplasmic reticulum Ca(2+) release. Acta Physiol (Oxf) 2007; 191:131-7. [PMID: 17565565 DOI: 10.1111/j.1748-1716.2007.01725.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM To investigate the importance and contribution of calmodulin-dependent protein kinase II (CaMKII) activity on sarcoplasmic reticulum (SR) Ca(2+)-release in response to different work intensities in single, intact muscle fibres. METHODS CaMKII activity was blocked in single muscle fibres using either the inhibitory peptide AC3-I or the pharmacological inhibitor KN-93. The effect on tetanic force production and [Ca(2+)](i) was determined during work of different intensities. The activity of CaMKII was assessed by mathematical modelling. RESULTS Using a standard protocol to induce fatigue (50x 70 Hz, 350 ms duration, every 2 s) the number of stimuli needed to induce fatigue was decreased from 47 +/- 3 contractions in control to 33 +/- 3 with AC3-I. KN-93 was a more potent inhibitor, decreasing the number of contractions needed to induce fatigue to 15 +/- 3. Tetanic [Ca(2+)](i) was 100 +/- 11%, 97 +/- 11% and 67 +/- 11% at the end of stimulation in control, AC3-I and KN-93 respectively. A similar inhibition was obtained using a high intensity protocol (20x 70 Hz, 200 ms duration, every 300 ms). However, using a long interval protocol (25x 70 Hz, 350 ms duration, every 5 s) no change was observed in either tetanic [Ca(2+)](i) or force when inhibiting CaMKII. A mathematical model used to investigate the activation pattern of CaMKII suggests that there is a threshold of active CaMKII that has to be surpassed in order for CaMKII to affect SR Ca(2+) release. CONCLUSION Our results show that CaMKII is crucial for maintaining proper SR Ca(2+) release and that this is regulated in a work intensity manner.
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Affiliation(s)
- J Aydin
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Geremia NM, Gordon T, Brushart TM, Al-Majed AA, Verge VMK. Electrical stimulation promotes sensory neuron regeneration and growth-associated gene expression. Exp Neurol 2007; 205:347-59. [PMID: 17428474 DOI: 10.1016/j.expneurol.2007.01.040] [Citation(s) in RCA: 290] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Revised: 01/16/2007] [Accepted: 01/19/2007] [Indexed: 12/29/2022]
Abstract
Brief electrical stimulation enhances the regenerative ability of axotomized motor [Nix, W.A., Hopf, H.C., 1983. Electrical stimulation of regenerating nerve and its effect on motor recovery. Brain Res. 272, 21-25; Al-Majed, A.A., Neumann, C.M., Brushart, T.M., Gordon, T., 2000. Brief electrical stimulation promotes the speed and accuracy of motor axonal regeneration. J. Neurosci. 20, 2602-2608] and sensory [Brushart, T.M., Jari, R., Verge, V., Rohde, C., Gordon, T., 2005. Electrical stimulation restores the specificity of sensory axon regeneration. Exp. Neurol. 194, 221-229] neurons. Here we examined the parameter of duration of stimulation on regenerative capacity, including the intrinsic growth programs, of sensory neurons. The effect of 20 Hz continuous electrical stimulation on the number of DRG sensory neurons that regenerate their axons was evaluated following transection and surgical repair of the femoral nerve trunk. Stimulation was applied proximal to the repair site for 1 h, 3 h, 1 day, 7 days or 14 days at the time of nerve repair. Following a 21-day regeneration period, DRG neurons that regenerated axons into the muscle and cutaneous sensory nerve branches were retrogradely identified. Stimulation of 1 h led to a significant increase in DRG neurons regenerating into cutaneous and muscle branches when compared to 0 h (sham) stimulation or longer periods of stimulation. Stimulation for 1 h also significantly increased the numbers of neurons that regenerated axons beyond the repair site 4 days after lesion and was correlated with a significant increase in expression of growth-associated protein 43 (GAP-43) mRNA in the regenerating neurons at 2 days post-repair. An additional indicator of heightened plasticity following 1 h stimulation was elevated expression of brain-derived neurotrophic factor (BDNF). The effect of brief stimulation on enhancing sensory and motoneuron regeneration holds promise for inducing improved peripheral nerve repair in the clinical setting.
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Affiliation(s)
- Nicole M Geremia
- Department of Anatomy and Cell Biology, Cameco MS/Neuroscience Research Center University of Saskatchewan, Saskatoon City Hospital, Saskatchewan, Canada
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Pitt GS. Calmodulin and CaMKII as molecular switches for cardiac ion channels: Fig. 1. Cardiovasc Res 2007; 73:641-7. [PMID: 17137569 DOI: 10.1016/j.cardiores.2006.10.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 10/20/2006] [Accepted: 10/25/2006] [Indexed: 10/23/2022] Open
Abstract
Because changes in intracellular Ca(2+) concentration are the final signals of electrical activity in excitable cells, many mechanisms have evolved to regulate Ca(2+) influx. Among the most important are those pathways that directly regulate the ion channels responsible for regulating and generating the Ca(2+) influx signal. Recent work has demonstrated that the Ca(2+) binding protein calmodulin (CaM) and the Ca(2+)/CaM-sensitive kinase CaMKII are important modulators of cardiac ion channels. Thus, Ca(2+) participates in feedback modulation to control electrical activity. This review highlights various mechanisms by which CaM and CaMKII regulate cardiovascular ion channel activity and presents a novel model for CaMKII regulation of Ca(V)1.2 Ca(2+) channel function.
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Affiliation(s)
- Geoffrey S Pitt
- Department of Medicine, Division of Cardiology, College of Physicians and Surgeons of Columbia University, 630 W 168th St, PH 7W 318, New York, NY 10032, USA.
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Affiliation(s)
- Jing Wu
- The University of Texas Medical Branch, Galveston, Texas, USA
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45
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Grueter CE, Abiria SA, Dzhura I, Wu Y, Ham AJL, Mohler PJ, Anderson ME, Colbran RJ. RETRACTED: L-Type Ca2+ Channel Facilitation Mediated by Phosphorylation of the β Subunit by CaMKII. Mol Cell 2006; 23:641-50. [PMID: 16949361 DOI: 10.1016/j.molcel.2006.07.006] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Revised: 05/19/2006] [Accepted: 07/10/2006] [Indexed: 11/27/2022]
Abstract
L-type Ca(2+) channels (LTCCs) are major entry points for Ca(2+) in many cells. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is associated with cardiac LTCC complexes and increases channel open probability (P(O)) to dynamically increase Ca(2+) current (I(Ca)) and augment cellular Ca(2+) signaling by a process called facilitation. However, the critical molecular mechanisms for CaMKII localization to LTCCs and I(Ca) facilitation in cardiomyocytes have not been defined. We show CaMKII binds to the LTCC beta(2a) subunit and preferentially phosphorylates Thr498 in beta(2a). Mutation of Thr498 to Ala (T498A) in beta(2a) prevents CaMKII-mediated increases in the P(O) of recombinant LTCCs. Moreover, expression of beta(2a)(T498A) in adult cardiomyocytes ablates CaMKII-mediated I(Ca) facilitation, demonstrating that phosphorylation of beta(2a) at Thr498 modulates native calcium channels. These findings reveal a molecular mechanism for targeting CaMKII to LTCCs and facilitating I(Ca) that may modulate Ca(2+) entry in diverse cell types coexpressing CaMKII and the beta(2a) subunit.
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Affiliation(s)
- Chad E Grueter
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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46
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Jung SR, Kim K, Hille B, Nguyen TD, Koh DS. Pattern of Ca2+ increase determines the type of secretory mechanism activated in dog pancreatic duct epithelial cells. J Physiol 2006; 576:163-78. [PMID: 16857709 PMCID: PMC1995640 DOI: 10.1113/jphysiol.2006.114876] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Intracellular calcium concentration ([Ca(2+)](i)) is a key factor controlling secretion from various cell types. We investigated how different patterns of [Ca(2+)](i) signals evoke salt secretion via ion transport mechanisms and mucin secretion via exocytosis in dog pancreatic duct epithelial cells (PDEC). Activation of epithelial P2Y(2) receptors by UTP generated two patterns of [Ca(2+)](i) change: 2-10 microm UTP induced [Ca(2+)](i) oscillations, whereas 100 microm UTP induced a sustained [Ca(2+)](i) increase, both in the micromolar range. As monitored by carbon-fibre amperometry, the sustained [Ca(2+)](i) increase stimulated a larger increase in exocytosis than [Ca(2+)](i) oscillations, despite their similar amplitude. In contrast, patch-clamp recordings revealed that [Ca(2+)](i) oscillations synchronously activated a K(+) current as efficiently as the sustained [Ca(2+)](i) increase. This K(+) current was mediated by intermediate-conductance Ca(2+)-activated K(+) channels (32 pS at -100 mV) which were sensitive to charybdotoxin and resistant to TEA. Activation of these Ca(2+)-dependent K(+) channels hyperpolarized the plasma membrane from a resting potential of -40 mV to -90 mV, as monitored in perforated whole-cell configuration, in turn enhancing Na(+)-independent, Cl(-)-dependent and DIDS-sensitive HCO(3)(-) secretion, as monitored through changes in intracellular pH. PDEC therefore encode concentrations of purinergic agonists as different patterns of [Ca(2+)](i) changes, which differentially stimulate K(+) channels, the Cl(-)-HCO(3)(-) exchanger, and exocytosis. Thus, in addition to amplitude, the temporal pattern of [Ca(2+)](i) increases is an important mechanism for transducing extracellular stimuli into different physiological effects.
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Affiliation(s)
- Seung-Ryoung Jung
- Department of Physiology and Biophysics, University of Washington, Health Sciences Bldg, Seattle, 98195-7290, USA
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47
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Burkert P, Duch C. Developmental changes of CaMKII localization, activity and function during postembryonic CNS remodelling in Manduca sexta. Eur J Neurosci 2006; 23:335-49. [PMID: 16420442 DOI: 10.1111/j.1460-9568.2005.04562.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Insect metamorphosis is a compelling example of postembryonic remodelling of neuronal structure and synaptic connectivity as larval and adult behaviours place distinct demands on the CNS. Holometabolous insects such as the moth Manduca sexta have long served as suitable models for the study of steroid effects on CNS remodelling, but activity and calcium-dependent mechanisms have been found to act in concert with hormonal signals. This study examines developmental changes in the localization and the activational state of CaMKII during postembryonic Manduca CNS remodelling. Western blotting, CaMKII purification and autophosphorylation with gamma(32)P-ATP indicate that the lepidopteran CNS may contain only one CaMKII isoform. In situ immunohistochemistry reveals developmental changes in the expression patterns of CaMKII in different types of thoracic neurons and in different neuronal compartments. Early pupal life is characterized by an increase in postsynaptic CaMKII localization, which coincides with a developmental increase in CaMKII activation. Both events correlate temporally with motoneuron dendritic filopodia collapse and rapid synaptogenesis, indicating a possible functional role for CaMKII for the postembryonic development of invertebrate motor circuitry. Substrate phosphorylation assays demonstrate that CaMKII activity in the ventral nerve cord reflects changes in calcium influx through voltage-activated channels as occurring in vivo during normal development.
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Affiliation(s)
- P Burkert
- Institute of Biology/Neurobiology, Free University of Berlin, 14195 Berlin, Germany
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Hudmon A, Schulman H, Kim J, Maltez JM, Tsien RW, Pitt GS. CaMKII tethers to L-type Ca2+ channels, establishing a local and dedicated integrator of Ca2+ signals for facilitation. ACTA ACUST UNITED AC 2006; 171:537-47. [PMID: 16275756 PMCID: PMC1343528 DOI: 10.1083/jcb.200505155] [Citation(s) in RCA: 262] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Ca2+-dependent facilitation (CDF) of voltage-gated calcium current is a powerful mechanism for up-regulation of Ca2+ influx during repeated membrane depolarization. CDF of L-type Ca2+ channels (Cav1.2) contributes to the positive force–frequency effect in the heart and is believed to involve the activation of Ca2+/calmodulin-dependent kinase II (CaMKII). How CaMKII is activated and what its substrates are have not yet been determined. We show that the pore-forming subunit α1C (Cavα1.2) is a CaMKII substrate and that CaMKII interaction with the COOH terminus of α1C is essential for CDF of L-type channels. Ca2+ influx triggers distinct features of CaMKII targeting and activity. After Ca2+-induced targeting to α1C, CaMKII becomes tightly tethered to the channel, even after calcium returns to normal levels. In contrast, activity of the tethered CaMKII remains fully Ca2+/CaM dependent, explaining its ability to operate as a calcium spike frequency detector. These findings clarify the molecular basis of CDF and demonstrate a novel enzymatic mechanism by which ion channel gating can be modulated by activity.
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Affiliation(s)
- Andy Hudmon
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA
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49
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Naoki H, Sakumura Y, Ishii S. Local signaling with molecular diffusion as a decoder of Ca2+ signals in synaptic plasticity. Mol Syst Biol 2005; 1:2005.0027. [PMID: 16729062 PMCID: PMC1681445 DOI: 10.1038/msb4100035] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Accepted: 10/25/2005] [Indexed: 11/24/2022] Open
Abstract
Synaptic plasticity is induced by the influx of calcium ions (Ca2+) through N-methyl-D-aspartate receptors (NMDARs), and the direction and strength of the response depend on the frequency of the synaptic inputs. Recent studies have shown that the direction of synaptic plasticity is also governed by two distinct NMDAR subtypes (NR1/NR2A, NR1/NR2B). How are the different types of regulation (frequency-dependent and receptor-specific) processed simultaneously? To clarify the molecular basis of this dual dependence of synaptic plasticity, we have developed a mathematical model of spatial Ca2+ signaling in a dendritic spine. Our simulations revealed that calmodulin (CaM) activation in the vicinity of NMDARs is strongly affected by the diffusion coefficient of CaM itself, and that this ‘local CaM diffusion system' works as a dual decoder of both the frequency of Ca2+ influxes and their postsynaptic current shapes, generated by two NMDAR subtypes, implying that spatial factors may underlie the complicated regulation scheme of synaptic plasticity.
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Affiliation(s)
- Honda Naoki
- Graduate School of Information Science, Nara Institute of Science and Technology, Takayama, Ikoma, Nara, Japan
| | - Yuichi Sakumura
- Graduate School of Information Science, Nara Institute of Science and Technology, Takayama, Ikoma, Nara, Japan
| | - Shin Ishii
- Graduate School of Information Science, Nara Institute of Science and Technology, Takayama, Ikoma, Nara, Japan
- Graduate School of Information Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan. Tel.: +81 743 72 5984; Fax: +81 743 72 5989; E-mail:
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50
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Liu J, Asuncion-Chin M, Liu P, Dopico AM. CaM kinase II phosphorylation of slo Thr107 regulates activity and ethanol responses of BK channels. Nat Neurosci 2005; 9:41-9. [PMID: 16341213 PMCID: PMC2574430 DOI: 10.1038/nn1602] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 10/21/2005] [Indexed: 01/01/2023]
Abstract
High-conductance, Ca(2+)-activated and voltage-gated (BK) channels set neuronal firing. They are almost universally activated by alcohol, leading to reduced neuronal excitability and neuropeptide release and to motor intoxication. However, several BK channels are inhibited by alcohol, and most other voltage-gated K(+) channels are refractory to drug action. BK channels are homotetramers (encoded by Slo1) that possess a unique transmembrane segment (S0), leading to a cytosolic S0-S1 loop. We identified Thr107 of bovine slo (bslo) in this loop as a critical residue that determines BK channel responses to alcohol. In addition, the activity of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in the cell controlled channel activity and alcohol modulation. Incremental CaMKII-mediated phosphorylation of Thr107 in the BK tetramer progressively increased channel activity and gradually switched the channel alcohol responses from robust activation to inhibition. Thus, CaMKII phosphorylation of slo Thr107 works as a 'molecular dimmer switch' that could mediate tolerance to alcohol, a form of neuronal plasticity.
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Affiliation(s)
- Jianxi Liu
- Department of Pharmacology, University of Tennessee Health Science Center, 874 Union Avenue, Memphis, Tennessee 38163, USA
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