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Husser MC, Pham NP, Law C, Araujo FRB, Martin VJJ, Piekny A. Endogenous tagging using split mNeonGreen in human iPSCs for live imaging studies. eLife 2024; 12:RP92819. [PMID: 38652106 PMCID: PMC11037917 DOI: 10.7554/elife.92819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024] Open
Abstract
Endogenous tags have become invaluable tools to visualize and study native proteins in live cells. However, generating human cell lines carrying endogenous tags is difficult due to the low efficiency of homology-directed repair. Recently, an engineered split mNeonGreen protein was used to generate a large-scale endogenous tag library in HEK293 cells. Using split mNeonGreen for large-scale endogenous tagging in human iPSCs would open the door to studying protein function in healthy cells and across differentiated cell types. We engineered an iPS cell line to express the large fragment of the split mNeonGreen protein (mNG21-10) and showed that it enables fast and efficient endogenous tagging of proteins with the short fragment (mNG211). We also demonstrate that neural network-based image restoration enables live imaging studies of highly dynamic cellular processes such as cytokinesis in iPSCs. This work represents the first step towards a genome-wide endogenous tag library in human stem cells.
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Affiliation(s)
| | - Nhat P Pham
- Biology Department, Concordia University, Montreal, Canada
| | - Chris Law
- Biology Department, Concordia University, Montreal, Canada
- Center for Microscopy and Cellular Imaging, Concordia University, Montreal, Canada
| | - Flavia R B Araujo
- Center for Applied Synthetic Biology, Concordia University, Montreal, Canada
| | - Vincent J J Martin
- Biology Department, Concordia University, Montreal, Canada
- Center for Applied Synthetic Biology, Concordia University, Montreal, Canada
| | - Alisa Piekny
- Biology Department, Concordia University, Montreal, Canada
- Center for Microscopy and Cellular Imaging, Concordia University, Montreal, Canada
- Center for Applied Synthetic Biology, Concordia University, Montreal, Canada
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Levy D, Abadchi SN, Shababi N, Ravari MR, Pirolli NH, Bergeron C, Obiorah A, Mokhtari-Esbuie F, Gheshlaghi S, Abraham JM, Smith IM, Powsner E, Solomon T, Harmon JW, Jay SM. Induced pluripotent stem cell-derived extracellular vesicles promote wound repair in a diabetic mouse model via an anti-inflammatory immunomodulatory mechanism. bioRxiv 2023:2023.03.19.533334. [PMID: 36993554 PMCID: PMC10055496 DOI: 10.1101/2023.03.19.533334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have recently been widely explored in clinical trials for treatment of diseases with complex pathophysiology. However, production of MSC EVs is currently hampered by donor-specific characteristics and limited ex vivo expansion capabilities before decreased potency, thus restricting their potential as a scalable and reproducible therapeutic. Induced pluripotent stem cells (iPSCs) represent a self-renewing source for obtaining differentiated iPSC-derived MSCs (iMSCs), circumventing both scalability and donor variability concerns for therapeutic EV production. Thus, we initially sought to evaluate the therapeutic potential of iMSC EVs. Interestingly, while utilizing undifferentiated iPSC EVs as a control, we found that their vascularization bioactivity was similar and their anti-inflammatory bioactivity was superior to donor-matched iMSC EVs in cell-based assays. To supplement this initial in vitro bioactivity screen, we employed a diabetic wound healing mouse model where both the pro-vascularization and anti-inflammatory activity of these EVs would be beneficial. In this in vivo model, iPSC EVs more effectively mediated inflammation resolution within the wound bed. Combined with the lack of additional differentiation steps required for iMSC generation, these results support the use of undifferentiated iPSCs as a source for therapeutic EV production with respect to both scalability and efficacy.
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Affiliation(s)
- Daniel Levy
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | | | - Niloufar Shababi
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Mohsen Rouhani Ravari
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Nicholas H. Pirolli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Cade Bergeron
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Angel Obiorah
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Farzad Mokhtari-Esbuie
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Shayan Gheshlaghi
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - John M. Abraham
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Ian M. Smith
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Emily Powsner
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Talia Solomon
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - John W. Harmon
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Steven M. Jay
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Program in Molecular and Cell Biology, University of Maryland, College Park, MD 20742, USA
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Lin G, Tepe B, McGrane G, Tipon RC, Croft G, Panwala L, Hope A, Liang AJH, Zuo Z, Byeon SK, Wang L, Pandey A, Bellen HJ. Exploring therapeutic strategies for infantile neuronal axonal dystrophy (INAD/PARK14). eLife 2023; 12:82555. [PMID: 36645408 PMCID: PMC9889087 DOI: 10.7554/elife.82555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/15/2023] [Indexed: 01/17/2023] Open
Abstract
Infantile neuroaxonal dystrophy (INAD) is caused by recessive variants in PLA2G6 and is a lethal pediatric neurodegenerative disorder. Loss of the Drosophila homolog of PLA2G6, leads to ceramide accumulation, lysosome expansion, and mitochondrial defects. Here, we report that retromer function, ceramide metabolism, the endolysosomal pathway, and mitochondrial morphology are affected in INAD patient-derived neurons. We show that in INAD mouse models, the same features are affected in Purkinje cells, arguing that the neuropathological mechanisms are evolutionary conserved and that these features can be used as biomarkers. We tested 20 drugs that target these pathways and found that Ambroxol, Desipramine, Azoramide, and Genistein alleviate neurodegenerative phenotypes in INAD flies and INAD patient-derived neural progenitor cells. We also develop an AAV-based gene therapy approach that delays neurodegeneration and prolongs lifespan in an INAD mouse model.
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Affiliation(s)
- Guang Lin
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Burak Tepe
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Geoff McGrane
- New York Stem Cell Foundation Research InstituteNew YorkUnited States
| | - Regine C Tipon
- New York Stem Cell Foundation Research InstituteNew YorkUnited States
| | - Gist Croft
- New York Stem Cell Foundation Research InstituteNew YorkUnited States
| | | | | | - Agnes JH Liang
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Seul Kee Byeon
- Department of Laboratory Medicine and Pathology, Mayo ClinicRochesterUnited States
| | - Lily Wang
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Akhilesh Pandey
- Department of Laboratory Medicine and Pathology, Mayo ClinicRochesterUnited States
- Manipal Academy of Higher Education, ManipalKarnatakaIndia
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
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Yu X, Ton AN, Niu Z, Morales BM, Chen J, Braz J, Lai MH, Barruet E, Liu H, Cheung K, Ali S, Chan T, Bigay K, Ho J, Nikolli I, Hansberry S, Wentworth K, Kriegstein A, Basbaum A, Hsiao EC. ACVR1-activating mutation causes neuropathic pain and sensory neuron hyperexcitability in humans. Pain 2023; 164:43-58. [PMID: 35442931 PMCID: PMC9582048 DOI: 10.1097/j.pain.0000000000002656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 03/01/2022] [Accepted: 04/08/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Altered bone morphogenetic protein (BMP) signaling is associated with many musculoskeletal diseases. However, it remains unknown whether BMP dysfunction has direct contribution to debilitating pain reported in many of these disorders. Here, we identified a novel neuropathic pain phenotype in patients with fibrodysplasia ossificans progressiva (FOP), a rare autosomal-dominant musculoskeletal disorder characterized by progressive heterotopic ossification. Ninety-seven percent of these patients carry an R206H gain-of-function point mutation in the BMP type I receptor ACVR1 (ACVR1 R206H ), which causes neofunction to Activin A and constitutively activates signaling through phosphorylated SMAD1/5/8. Although patients with FOP can harbor pathological lesions in the peripheral and central nervous system, their etiology and clinical impact are unclear. Quantitative sensory testing of patients with FOP revealed significant heat and mechanical pain hypersensitivity. Although there was no major effect of ACVR1 R206H on differentiation and maturation of nociceptive sensory neurons (iSNs) derived from FOP induced pluripotent stem cells, both intracellular and extracellular electrophysiology analyses of the ACVR1 R206H iSNs displayed ACVR1-dependent hyperexcitability, a hallmark of neuropathic pain. Consistent with this phenotype, we recorded enhanced responses of ACVR1 R206H iSNs to TRPV1 and TRPA1 agonists. Thus, activated ACVR1 signaling can modulate pain processing in humans and may represent a potential target for pain management in FOP and related BMP pathway diseases.
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Affiliation(s)
- Xiaobing Yu
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, United States
| | - Amy N. Ton
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Zejun Niu
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, United States
- Department of Anesthesiology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Blanca M. Morales
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Jiadong Chen
- Department of Neurology, University of California, San Francisco, CA, United States. Dr. Chen is now with the Department of Neurology of Second Affiliated Hospital, Centre for Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Joao Braz
- Department of Anatomy, University of California San Francisco, San Francisco, CA, United States
| | - Michael H. Lai
- J. David Gladstone Institutes, San Francisco, CA, United States
| | - Emilie Barruet
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Hongju Liu
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, United States
- Department of Anesthesiology, Peking Union Medical College Hospital, Beijing, China
| | - Kin Cheung
- BioSAS Consulting, Inc, Wellesley, MA, United States
| | - Syed Ali
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, United States
| | - Tea Chan
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Katherine Bigay
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Jennifer Ho
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Ina Nikolli
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Steven Hansberry
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
- California Institute of Regenerative Medicine Bridges to Stem Cell Research Program, San Francisco State University, San Francisco, CA, United States
| | - Kelly Wentworth
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
| | - Arnold Kriegstein
- Department of Neurology, University of California, San Francisco, CA, United States. Dr. Chen is now with the Department of Neurology of Second Affiliated Hospital, Centre for Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Allan Basbaum
- Department of Anatomy, University of California San Francisco, San Francisco, CA, United States
| | - Edward C. Hsiao
- Division of Endocrinology and Metabolism, Department of Medicine, The Institute for Human Genetics, and the Program in Craniofacial Biology, University of California, San Francisco, CA, United States
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Wu CI, Vinton EA, Pearse RV, Heo K, Aylward AJ, Hsieh YC, Bi Y, Adeleye S, Fancher S, Duong DM, Seyfried NT, Schwarz TL, Young-Pearse TL. APP and DYRK1A regulate axonal and synaptic vesicle protein networks and mediate Alzheimer's pathology in trisomy 21 neurons. Mol Psychiatry 2022; 27:1970-1989. [PMID: 35194165 PMCID: PMC9133025 DOI: 10.1038/s41380-022-01454-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 01/18/2022] [Indexed: 11/09/2022]
Abstract
Trisomy 21 (T21) causes Down syndrome and an early-onset form of Alzheimer's disease (AD). Here, we used human induced pluripotent stem cells (hiPSCs) along with CRISPR-Cas9 gene editing to investigate the contribution of chromosome 21 candidate genes to AD-relevant neuronal phenotypes. We utilized a direct neuronal differentiation protocol to bypass neurodevelopmental cell fate phenotypes caused by T21 followed by unbiased proteomics and western blotting to define the proteins dysregulated in T21 postmitotic neurons. We show that normalization of copy number of APP and DYRK1A each rescue elevated tau phosphorylation in T21 neurons, while reductions of RCAN1 and SYNJ1 do not. To determine the T21 alterations relevant to early-onset AD, we identified common pathways altered in familial Alzheimer's disease neurons and determined which of these were rescued by normalization of APP and DYRK1A copy number in T21 neurons. These studies identified disruptions in T21 neurons in both the axonal cytoskeletal network and presynaptic proteins that play critical roles in axonal transport and synaptic vesicle cycling. These alterations in the proteomic profiles have functional consequences: fAD and T21 neurons exhibit dysregulated axonal trafficking and T21 neurons display enhanced synaptic vesicle release. Taken together, our findings provide insights into the initial molecular alterations within neurons that ultimately lead to synaptic loss and axonal degeneration in Down syndrome and early-onset AD.
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Affiliation(s)
- Chun-I Wu
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Elizabeth A Vinton
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
| | - Richard V Pearse
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Keunjung Heo
- Harvard Medical School, Boston, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Aimee J Aylward
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
| | - Yi-Chen Hsieh
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Yan Bi
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
| | - Sopefoluwa Adeleye
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
| | - Seeley Fancher
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA
| | - Duc M Duong
- Department of Biochemistry, Emory School of Medicine, Atlanta, GA, USA
- Department of Neurology, Emory School of Medicine, Atlanta, GA, USA
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory School of Medicine, Atlanta, GA, USA
- Department of Neurology, Emory School of Medicine, Atlanta, GA, USA
| | - Thomas L Schwarz
- Harvard Medical School, Boston, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Tracy L Young-Pearse
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
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Nations CC, Pavani G, French DL, Gadue P. Modeling genetic platelet disorders with human pluripotent stem cells: mega-progress but wanting more on our plate(let). Curr Opin Hematol 2021; 28:308-314. [PMID: 34397590 PMCID: PMC8371829 DOI: 10.1097/moh.0000000000000671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Megakaryocytes are rare hematopoietic cells that play an instrumental role in hemostasis, and other important biological processes such as immunity and wound healing. With the advent of cell reprogramming technologies and advances in differentiation protocols, it is now possible to obtain megakaryocytes from any pluripotent stem cell (PSC) via hematopoietic induction. Here, we review recent advances in PSC-derived megakaryocyte (iMK) technology, focusing on platform validation, disease modeling and current limitations. RECENT FINDINGS A comprehensive study confirmed that iMK can recapitulate many transcriptional and functional aspects of megakaryocyte and platelet biology, including variables associated with complex genetic traits such as sex and race. These findings were corroborated by several pathological models in which iMKs revealed molecular mechanisms behind inherited platelet disorders and assessed the efficacy of novel pharmacological interventions. However, current differentiation protocols generate primarily embryonic iMK, limiting the clinical and translational potential of this system. SUMMARY iMK are strong candidates to model pathologic mutations involved in platelet defects and develop innovative therapeutic strategies. Future efforts on generating definitive hematopoietic progenitors would improve current platelet generation protocols and expand our capacity to model neonatal and adult megakaryocyte disorders.
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Affiliation(s)
- Catriana C Nations
- Department of Cell and Molecular Biology, University of Pennsylvania Perelman School of Medicine
- Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia
| | - Giulia Pavani
- Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia
| | - Deborah L French
- Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine and Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Paul Gadue
- Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine and Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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Akiyama H, Jalloh S, Park S, Lei M, Mostoslavsky G, Gummuluru S. Expression of HIV-1 Intron-Containing RNA in Microglia Induces Inflammatory Responses. J Virol 2021; 95:JVI. [PMID: 33298546 DOI: 10.1128/JVI.01386-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chronic neuroinflammation is observed in HIV+ individuals on suppressive combination antiretroviral therapy (cART) and is thought to cause HIV-associated neurocognitive disorders. We have recently reported that expression of HIV intron-containing RNA (icRNA) in productively infected monocyte-derived macrophages induces pro-inflammatory responses. Microglia, yolk sac-derived brain-resident tissue macrophages, are the primary HIV-1 infected cell type in the central nervous system (CNS). In this study, we tested the hypothesis that persistent expression of HIV icRNA in primary human microglia induces innate immune activation. We established multiple orthogonal primary human microglia-like cell cultures including peripheral blood monocyte-derived microglia (MDMG) and induced pluripotent stem cell (iPSC)-derived microglia. Unlike MDMG, human iPSC-derived microglia (hiMG), which phenotypically mimic primary CNS microglia, were robustly infected with replication competent HIV-1, and establishment of productive HIV-1 infection and de novo viral gene expression led to pro-inflammatory cytokine production. Blocking of HIV-1 icRNA expression, but not multiply spliced viral RNA, either via infection with virus expressing a Rev-mutant deficient for HIV icRNA nuclear export or infection in the presence of small molecule inhibitor of CRM1-mediated viral icRNA nuclear export pathway, attenuated induction of innate immune responses. These studies suggest that Rev-CRM1-dependent nuclear export and cytosolic sensing of HIV-1 icRNA induces pro-inflammatory responses in productively infected microglia. Novel strategies targeting HIV icRNA expression specifically are needed to suppress HIV-induced neuroinflammation.
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Brenes A, Hukelmann J, Bensaddek D, Lamond AI. Multibatch TMT Reveals False Positives, Batch Effects and Missing Values. Mol Cell Proteomics 2019; 18:1967-1980. [PMID: 31332098 PMCID: PMC6773557 DOI: 10.1074/mcp.ra119.001472] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/14/2019] [Indexed: 12/31/2022] Open
Abstract
Multiplexing strategies for large-scale proteomic analyses have become increasingly prevalent, tandem mass tags (TMT) in particular. Here we used a large iPSC proteomic experiment with twenty-four 10-plex TMT batches to evaluate the effect of integrating multiple TMT batches within a single analysis. We identified a significant inflation rate of protein missing values as multiple batches are integrated and show that this pattern is aggravated at the peptide level. We also show that without normalization strategies to address the batch effects, the high precision of quantitation within a single multiplexed TMT batch is not reproduced when data from multiple TMT batches are integrated.Further, the incidence of false positives was studied by using Y chromosome peptides as an internal control. The iPSC lines quantified in this data set were derived from both male and female donors, hence the peptides mapped to the Y chromosome should be absent from female lines. Nonetheless, these Y chromosome-specific peptides were consistently detected in the female channels of all TMT batches. We then used the same Y chromosome specific peptides to quantify the level of ion coisolation as well as the effect of primary and secondary reporter ion interference. These results were used to propose solutions to mitigate the limitations of multi-batch TMT analyses. We confirm that including a common reference line in every batch increases precision by facilitating normalization across the batches and we propose experimental designs that minimize the effect of cross population reporter ion interference.
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Affiliation(s)
- Alejandro Brenes
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, United Kingdom
| | - Jens Hukelmann
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, United Kingdom
| | - Dalila Bensaddek
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, United Kingdom
| | - Angus I Lamond
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, United Kingdom.
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Ovadia EM, Colby DW, Kloxin AM. Designing well-defined photopolymerized synthetic matrices for three-dimensional culture and differentiation of induced pluripotent stem cells. Biomater Sci 2018; 6:1358-1370. [PMID: 29675520 PMCID: PMC6126667 DOI: 10.1039/c8bm00099a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Induced pluripotent stem cells (iPSCs) are of interest for the study of disease, where these cells can be derived from patients and have the potential to be differentiated into any cell type; however, three-dimensional (3D) culture and differentiation of iPSCs within well-defined synthetic matrices for these applications remains limited. Here, we aimed to establish synthetic cell-degradable hydrogels that allow precise presentation of specific biochemical cues for 3D culture of iPSCs with relevance for hypothesis testing and lineage-specific differentiation. We synthesized poly(ethylene glycol)-(PEG)-peptide-based hydrogels by photoinitiated step growth polymerization and used them to test the hypothesis that the viability of iPSCs within these matrices could be rescued with appropriate biochemical cues inspired by proteins and integrins important for iPSC culture on Matrigel. Specifically, we selected a range of motifs inspired by iPSC binding to Matrigel, including laminin-derived IKVAV and YIGSR, α5β1-binding PHSRNG10RGDS, αvβ5-binding KKQRFRHRNRKG, and RGDS that is known to bind a variety of integrins for generally promoting cell adhesion. YIGSR and PHSRNG10RGDS resulted in the highest iPSC viability, where binding of β1 integrin was key, and these permissive compositions also allowed iPSC differentiation into neural progenitor cells (NPCs) (decreased oct4 expression and increased pax6 expression) in response to soluble factors. The resulting NPCs formed clusters of different sizes in response to each peptide, suggesting that matrix biochemical cues affect iPSC proliferation and clustering in 3D culture. In summary, we have established photopolymerizable synthetic matrices for the encapsulation, culture, and differentiation of iPSCs for studies of cell-matrix interactions and deployment in disease models.
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Affiliation(s)
- Elisa M Ovadia
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA.
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Foster AA, Dewi RE, Cai L, Hou L, Strassberg Z, Alcazar C, Heilshorn SC, Huang NF. Protein-engineered hydrogels enhance the survival of induced pluripotent stem cell-derived endothelial cells for treatment of peripheral arterial disease. Biomater Sci 2018; 6:614-622. [PMID: 29406542 PMCID: PMC5829050 DOI: 10.1039/c7bm00883j] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A key feature of peripheral arterial disease (PAD) is damage to endothelial cells (ECs), resulting in lower limb pain and restricted blood flow. Recent preclinical studies demonstrate that the transplantation of ECs via direct injection into the affected limb can result in significantly improved blood circulation. Unfortunately, the clinical application of this therapy has been limited by low cell viability and poor cell function. To address these limitations we have developed an injectable, recombinant hydrogel, termed SHIELD (Shear-thinning Hydrogel for Injectable Encapsulation and Long-term Delivery) for cell transplantation. SHIELD provides mechanical protection from cell membrane damage during syringe flow. Additionally, secondary in situ crosslinking provides a reinforcing network to improve cell retention, thereby augmenting the therapeutic benefit of cell therapy. In this study, we demonstrate the improved acute viability of human induced pluripotent stem cell-derived endothelial cells (iPSC-ECs) following syringe injection delivery in SHIELD, compared to saline. Using a murine hind limb ischemia model of PAD, we demonstrate enhanced iPSC-EC retention in vivo and improved neovascularization of the ischemic limb based on arteriogenesis following transplantation of iPSC-ECs delivered in SHIELD.
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Affiliation(s)
- Abbygail A. Foster
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Ruby E. Dewi
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Lei Cai
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Luqia Hou
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | | | - Cynthia Alcazar
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Sarah C. Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Ngan F. Huang
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Cardiothoracic Surgery, Stanford, CA, USA
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11
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Aguilo F, Walsh MJ. The N 6-Methyladenosine RNA modification in pluripotency and reprogramming. Curr Opin Genet Dev 2017; 46:77-82. [PMID: 28683341 PMCID: PMC5626584 DOI: 10.1016/j.gde.2017.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/26/2017] [Accepted: 06/08/2017] [Indexed: 12/25/2022]
Abstract
Chemical modifications of RNA provide a direct and rapid way to manipulate the existing transcriptome, allowing rapid responses to the changing environment further enriching the regulatory capacity of RNA. N6-Methyladenosine (m6A) has been identified as the most abundant internal modification of messenger RNA in eukaryotes, linking external stimuli to an intricate network of transcriptional, post-transcriptional and translational processes. M6A modification affects a broad spectrum of cellular functions, including maintenance of the pluripotency of embryonic stem cells (ESCs) and the reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). In this review, we summarize the most recent findings on m6A modification with special focus on the different studies describing how m6A is implicated in ESC self-renewal, cell fate specification and iPSC generation.
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Affiliation(s)
- Francesca Aguilo
- Wallenberg Centre for Molecular Medicine (WCMM), Umeå University, SE-901 85 Umeå , Sweden,Department of Medical Biosciences, Umeå University, SE-901 85 Umeå , Sweden
| | - Martin J. Walsh
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA,Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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12
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Madison JM, Zhou F, Nigam A, Hussain A, Barker DD, Nehme R, van der Ven K, Hsu J, Wolf P, Fleishman M, O’Dushlaine C, Rose S, Chambert K, Lau FH, Ahfeldt T, Rueckert EH, Sheridan SD, Fass DM, Nemesh J, Mullen TE, Daheron L, McCarroll S, Sklar P, Perlis RH, Haggarty SJ. Characterization of bipolar disorder patient-specific induced pluripotent stem cells from a family reveals neurodevelopmental and mRNA expression abnormalities. Mol Psychiatry 2015; 20:703-17. [PMID: 25733313 PMCID: PMC4440839 DOI: 10.1038/mp.2015.7] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 10/29/2014] [Accepted: 12/19/2014] [Indexed: 02/07/2023]
Abstract
Bipolar disorder (BD) is a common neuropsychiatric disorder characterized by chronic recurrent episodes of depression and mania. Despite evidence for high heritability of BD, little is known about its underlying pathophysiology. To develop new tools for investigating the molecular and cellular basis of BD, we applied a family-based paradigm to derive and characterize a set of 12 induced pluripotent stem cell (iPSC) lines from a quartet consisting of two BD-affected brothers and their two unaffected parents. Initially, no significant phenotypic differences were observed between iPSCs derived from the different family members. However, upon directed neural differentiation, we observed that CXCR4 (CXC chemokine receptor-4) expressing central nervous system (CNS) neural progenitor cells (NPCs) from both BD patients compared with their unaffected parents exhibited multiple phenotypic differences at the level of neurogenesis and expression of genes critical for neuroplasticity, including WNT pathway components and ion channel subunits. Treatment of the CXCR4(+) NPCs with a pharmacological inhibitor of glycogen synthase kinase 3, a known regulator of WNT signaling, was found to rescue a progenitor proliferation deficit in the BD patient NPCs. Taken together, these studies provide new cellular tools for dissecting the pathophysiology of BD and evidence for dysregulation of key pathways involved in neurodevelopment and neuroplasticity. Future generation of additional iPSCs following a family-based paradigm for modeling complex neuropsychiatric disorders in conjunction with in-depth phenotyping holds promise for providing insights into the pathophysiological substrates of BD and is likely to inform the development of targeted therapeutics for its treatment and ideally prevention.
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Affiliation(s)
- Jon M. Madison
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA,Correspondence: (JM), (SJH)
| | - Fen Zhou
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Aparna Nigam
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ali Hussain
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Douglas D. Barker
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA
| | - Ralda Nehme
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA,Department of Neurology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
| | - Karlijn van der Ven
- Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Jenny Hsu
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Pavlina Wolf
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Neurology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
| | - Morgan Fleishman
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Colm O’Dushlaine
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA
| | - Sam Rose
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA
| | - Kimberly Chambert
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA
| | - Frank H. Lau
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA
| | - Tim Ahfeldt
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA
| | - Erroll H. Rueckert
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA,Chemical Neurobiology Laboratory, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Steven D. Sheridan
- Chemical Neurobiology Laboratory, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Daniel M. Fass
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Department of Neurology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA,Chemical Neurobiology Laboratory, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - James Nemesh
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas E. Mullen
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Laurence Daheron
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA
| | - Steve McCarroll
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Pamela Sklar
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Roy H. Perlis
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA,Chemical Neurobiology Laboratory, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Stephen J. Haggarty
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA,Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Neurology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA,Chemical Neurobiology Laboratory, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA,Correspondence: (JM), (SJH)
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13
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Wang M, Hill MN, Zhang L, Gorzalka BB, Hillard CJ, Alger BE. Acute restraint stress enhances hippocampal endocannabinoid function via glucocorticoid receptor activation. J Psychopharmacol 2012; 26:56-70. [PMID: 21890595 PMCID: PMC3373303 DOI: 10.1177/0269881111409606] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Exposure to behavioural stress normally triggers a complex, multilevel response of the hypothalamic-pituitary-adrenal (HPA) axis that helps maintain homeostatic balance. Although the endocannabinoid (eCB) system (ECS) is sensitive to chronic stress, few studies have directly addressed its response to acute stress. Here we show that acute restraint stress enhances eCB-dependent modulation of GABA release measured by whole-cell voltage clamp of inhibitory postsynaptic currents (IPSCs) in rat hippocampal CA1 pyramidal cells in vitro. Both Ca(2+)-dependent, eCB-mediated depolarization-induced suppression of inhibition (DSI), and muscarinic cholinergic receptor (mAChR)-mediated eCB mobilization are enhanced following acute stress exposure. DSI enhancement is dependent on the activation of glucocorticoid receptors (GRs) and is mimicked by both in vivo and in vitro corticosterone treatment. This effect does not appear to involve cyclooxygenase-2 (COX-2), an enzyme that can degrade eCBs; however, treatment of hippocampal slices with the L-type calcium (Ca(2+)) channel inhibitor, nifedipine, reverses while an agonist of these channels mimics the effect of in vivo stress. Finally, we find that acute stress produces a delayed (by 30 min) increase in the hippocampal content of 2-arachidonoylglycerol, the eCB responsible for DSI. These results support the hypothesis that the ECS is a biochemical effector of glucocorticoids in the brain, linking stress with changes in synaptic strength.
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Affiliation(s)
- Meina Wang
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA 21201
| | - Matthew N. Hill
- Department of Psychology, University of British Columbia, Vancouver, BC Canada
| | - Longhua Zhang
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA 21201
| | - Boris B. Gorzalka
- Department of Psychology, University of British Columbia, Vancouver, BC Canada
| | - Cecilia J. Hillard
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA 53226
| | - Bradley E. Alger
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA 21201
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14
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ALLISON DAVIDW, WILCOX REBECCAS, ELLEFSEN KYLEL, ASKEW CAITLINE, HANSEN DAVIDM, WILCOX JEFFREYD, SANDOVAL STEPHANIES, EGGETT DENNISL, YANAGAWA YUCHIO, STEFFENSEN SCOTTC. Mefloquine effects on ventral tegmental area dopamine and GABA neuron inhibition: a physiologic role for connexin-36 GAP junctions. Synapse 2011; 65:804-13. [PMID: 21218452 PMCID: PMC4056588 DOI: 10.1002/syn.20907] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 12/11/2010] [Indexed: 11/10/2022]
Abstract
Connexin-36 (Cx36) gap junctions (GJs) appear to be involved in the synchronization of GABA interneurons in many brain areas. We have previously identified a population of Cx36-connected ventral tegmental area (VTA) GABA neurons that may regulate mesolimbic dopamine (DA) neurotransmission, a system implicated in reward from both natural behaviors and drugs of abuse. The aim of this study was to determine the effect mefloquine (MFQ) has on midbrain DA and GABA neuron inhibition, and the role Cx36 GJs play in regulating midbrain VTA DA neuron activity in mice. In brain slices from adolescent wild-type (WT) mice the Cx36-selective GJ blocker mefloquine (MFQ, 25 μM) increased VTA DA neuron sIPSC frequency sixfold, and mIPSC frequency threefold. However, in Cx36 KO mice, MFQ only increased sIPSC and mIPSC frequency threefold. The nonselective GJ blocker carbenoxolone (CBX, 100 μM) increased DA neuron sIPSC frequency twofold in WT mice, did not affect Cx36 KO mouse sIPSCs, and did not affect mIPSCs in WT or Cx36 KO mice. Interestingly, MFQ had no effect on VTA GABA neuron sIPSC frequency. We also examined MFQ effects on VTA DA neuron firing rate and current-evoked spiking in WT and Cx36 KO mice, and found that MFQ decreased WT DA neuron firing rate and current-evoked spiking, but did not alter these measures in Cx36 KO mice. Taken together these findings suggest that blocking Cx36 GJs increases VTA DA neuron inhibition, and that GJs play in key role in regulating inhibition of VTA DA neurons. Synapse, 2011. © 2011 Wiley-Liss, Inc.
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15
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Lemos JC, Zhang G, Walsh T, Kirby LG, Akanwa A, Brooks-Kayal A, Beck SG. Stress-hyperresponsive WKY rats demonstrate depressed dorsal raphe neuronal excitability and dysregulated CRF-mediated responses. Neuropsychopharmacology 2011; 36:721-34. [PMID: 21160465 DOI: 10.1038/npp.2010.200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Major depression is a debilitating psychiatric disease that may be precipitated by a dysregulation of stress neurocircuitry caused by chronic or severe stress exposure. Moreover, hyperresponsivity to stressors correlates with depressed mood and may contribute to the etiology of major depression. The serotonergic dorsal raphe nucleus (DRN) is an important site in the neurocircuitry underlying behavioral responses to stressors, and is tightly regulated, in part, by a combination of intrinsic cell properties, autoinhibition, and GABAergic synaptic transmission. The stress-related neurotransmitter corticotropin-releasing factor (CRF) modulates DRN neuronal excitability and subsequent 5-HT release in the forebrain. Wistar Kyoto (WKY) rats exhibit exaggerated behavioral responses to stressors, that is, stress hyperresponsivity, and are considered an animal model of depression. To better understand the neurobiological basis of the stress hyperresponsivity, we used a combination of mRNA analysis and whole-cell electrophysiological techniques to measure differences in intrinsic activity and receptor response, in 5-HT- and non-5-HT-containing neurons of the DRN in WKY rats compared with Sprague-Dawley controls. In the WKY rat, there was a decrease in the neuronal excitability of 5-HT neurons coupled with decreased TPH2 production. Additionally, we found that CRF did not increase GABAergic activity in 5-HT neurons as is normally seen in 5-HT neurons of Sprague-Dawley controls. The CRF modulation of 5-HT DRN neurotransmission at the single-cell level is selectively disrupted in the WKY animal model of depression and may be one of the cellular correlates underlying depression.
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16
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Szabó GG, Holderith N, Gulyás AI, Freund TF, Hájos N. Distinct synaptic properties of perisomatic inhibitory cell types and their different modulation by cholinergic receptor activation in the CA3 region of the mouse hippocampus. Eur J Neurosci 2010; 31:2234-46. [PMID: 20529124 PMCID: PMC2916217 DOI: 10.1111/j.1460-9568.2010.07292.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/16/2010] [Accepted: 04/23/2010] [Indexed: 01/13/2023]
Abstract
Perisomatic inhibition originates from three types of GABAergic interneurons in cortical structures, including parvalbumin-containing fast-spiking basket cells (FSBCs) and axo-axonic cells (AACs), as well as cholecystokinin-expressing regular-spiking basket cells (RSBCs). These interneurons may have significant impact in various cognitive processes, and are subjects of cholinergic modulation. However, it is largely unknown how cholinergic receptor activation modulates the function of perisomatic inhibitory cells. Therefore, we performed paired recordings from anatomically identified perisomatic interneurons and pyramidal cells in the CA3 region of the mouse hippocampus. We determined the basic properties of unitary inhibitory postsynaptic currents (uIPSCs) and found that they differed among cell types, e.g. GABA released from axon endings of AACs evoked uIPSCs with the largest amplitude and with the longest decay measured at room temperature. RSBCs could also release GABA asynchronously, the magnitude of the release increasing with the discharge frequency of the presynaptic interneuron. Cholinergic receptor activation by carbachol significantly decreased the uIPSC amplitude in all three types of cell pairs, but to different extents. M2-type muscarinic receptors were responsible for the reduction in uIPSC amplitudes in FSBC- and AAC-pyramidal cell pairs, while an antagonist of CB(1) cannabinoid receptors recovered the suppression in RSBC-pyramidal cell pairs. In addition, carbachol suppressed or even eliminated the short-term depression of uIPSCs in FSBC- and AAC-pyramidal cell pairs in a frequency-dependent manner. These findings suggest that not only are the basic synaptic properties of perisomatic inhibitory cells distinct, but acetylcholine can differentially control the impact of perisomatic inhibition from different sources.
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Affiliation(s)
- Gergely G Szabó
- Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of SciencesH-1083 Budapest, Hungary
| | - Noémi Holderith
- Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of SciencesH-1083 Budapest, Hungary
| | - Attila I Gulyás
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapest, Hungary
| | - Tamás F Freund
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapest, Hungary
| | - Norbert Hájos
- Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of SciencesH-1083 Budapest, Hungary
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17
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Maccarrone M, Rossi S, Bari M, De Chiara V, Rapino C, Musella A, Bernardi G, Bagni C, Centonze D. Abnormal mGlu 5 receptor/endocannabinoid coupling in mice lacking FMRP and BC1 RNA. Neuropsychopharmacology 2010; 35:1500-9. [PMID: 20393458 DOI: 10.1038/npp.2010.19] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Transcriptional silencing of the gene encoding the fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS). FMRP acts as a translational repressor at central synapses, and molecular and synaptic plasticity studies have shown that the absence of this protein alters metabotropic glutamate 5 receptors (mGlu5Rs)-mediated signaling. In the striatum of mice lacking FMRP, we found enhanced activity of diacylglycerol lipase (DAGL), the enzyme limiting 2-arachidonoylglicerol (2-AG) synthesis, associated with altered sensitivity of GABA synapses to the mobilization of this endocannabinoid by mGlu5R stimulation with DHPG. Mice lacking another repressor of synaptic protein synthesis, BC1 RNA, also showed potentiated mGlu5R-driven 2-AG responses, indicating that both FMRP and BC1 RNA act as physiological constraints of mGlu5R/endocannabinoid coupling at central synapses. The effects of FMRP ablation on DAGL activity and on DHPG-mediated inhibition of GABA synapses were enhanced by simultaneous genetic inactivation of FMRP and BC1 RNA. In double FMRP and BC1 RNA lacking mice, striatal levels of 2-AG were also enhanced compared with control animals and to single mutants. Our data indicate for the first time that mGlu5R-driven endocannabinoid signaling in the striatum is under the control of both FMRP and BC1 RNA. The abnormal mGlu5R/2-AG coupling found in FMRP-KO mice emphasizes the involvement of mGlu5Rs in the synaptic defects of FXS, and identifies the modulation of the endocannabinoid system as a novel target for the treatment of this severe neuropsychiatric disorder.
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18
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De Chiara V, Errico F, Musella A, Rossi S, Mataluni G, Sacchetti L, Siracusano A, Castelli M, Cavasinni F, Bernardi G, Usiello A, Centonze D. Voluntary exercise and sucrose consumption enhance cannabinoid CB1 receptor sensitivity in the striatum. Neuropsychopharmacology 2010; 35:374-87. [PMID: 19776732 DOI: 10.1038/npp.2009.141] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The endogenous cannabinoid system is involved in the regulation of the central reward pathway. Running wheel and sucrose consumption have rewarding and reinforcing properties in rodents, and share many neurochemical and behavioral characteristics with drug addiction. In this study, we investigated whether running wheel or sucrose consumption altered the sensitivity of striatal synapses to the activation of cannabinoid CB1 receptors. We found that cannabinoid CB1 receptor-mediated presynaptic control of striatal inhibitory postsynaptic currents was remarkably potentiated after these environmental manipulations. In contrast, the sensitivity of glutamate synapses to CB1 receptor stimulation was unaltered, as well as that of GABA synapses to the stimulation of presynaptic GABAB receptors. The sensitization of cannabinoid CB1 receptor-mediated responses was slowly reversible after the discontinuation of running wheel or sucrose consumption, and was also detectable following the mobilization of endocannabinoids by metabotropic glutamate receptor 5 stimulation. Finally, we found that the upregulation of cannabinoid transmission induced by wheel running or sucrose had a crucial role in the protective effects of these environmental manipulations against the motor and synaptic consequences of stress.
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19
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Beckstead MJ, Gantz SC, Ford CP, Stenzel-Poore MP, Phillips PEM, Mark GP, Williams JT. CRF enhancement of GIRK channel-mediated transmission in dopamine neurons. Neuropsychopharmacology 2009; 34:1926-35. [PMID: 19279570 PMCID: PMC3640552 DOI: 10.1038/npp.2009.25] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dopamine neurons in the ventral midbrain contribute to learning and memory of natural and drug-related rewards. Corticotropin-releasing factor (CRF), a stress-related peptide, is thought to be involved in aspects of relapse following drug withdrawal, but the cellular actions are poorly understood. This study investigates the action of CRF on G-protein-linked inhibitory postsynaptic currents (IPSCs) mediated by GIRK (Kir3) channels in dopamine neurons. CRF enhanced the amplitude and slowed the kinetics of IPSCs following activation of D2-dopamine and GABA(B) receptors. This action was postsynaptic and dependent on the CRF(1) receptor. The enhancement induced by CRF was attenuated by repeated in vivo exposures to psychostimulants or restraint stress. The results indicate that CRF influences dopamine- and GABA-mediated inhibition in the midbrain, suggesting implications for the chronic actions of psychostimulants and stress on dopamine-mediated behaviors.
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Affiliation(s)
- Michael J Beckstead
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA;
,Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
| | - Stephanie C Gantz
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
| | - Christopher P Ford
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
| | - Mary P Stenzel-Poore
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA;
| | - Paul EM Phillips
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA;
,Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Gregory P Mark
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA;
| | - John T Williams
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
,
Correspondence: Vollum Institute, L474, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA, Tel: + 503 494 5465, Fax + 503 494 6972,
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20
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Centonze D, Rossi S, Napoli I, Mercaldo V, Lacoux C, Ferrari F, Ciotti MT, De Chiara V, Prosperetti C, Maccarrone M, Fezza F, Calabresi P, Bernardi G, Bagni C. The brain cytoplasmic RNA BC1 regulates dopamine D2 receptor-mediated transmission in the striatum. J Neurosci 2007; 27:8885-92. [PMID: 17699670 PMCID: PMC6672174 DOI: 10.1523/jneurosci.0548-07.2007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 06/07/2007] [Accepted: 06/22/2007] [Indexed: 11/21/2022] Open
Abstract
Dopamine D(2) receptor (D(2)DR)-mediated transmission in the striatum is remarkably flexible, and changes in its efficacy have been heavily implicated in a variety of physiological and pathological conditions. Although receptor-associated proteins are clearly involved in specific forms of synaptic plasticity, the molecular mechanisms regulating the sensitivity of D(2) receptors in this brain area are essentially obscure. We have studied the physiological responses of the D(2)DR stimulations in mice lacking the brain cytoplasmic RNA BC1, a small noncoding dendritically localized RNA that is supposed to play a role in mRNA translation. We show that the efficiency of D(2)-mediated transmission regulating striatal GABA synapses is under the control of BC1 RNA, through a negative influence on D(2) receptor protein level affecting the functional pool of receptors. Ablation of the BC1 gene did not result in widespread dysregulation of synaptic transmission, because the sensitivity of cannabinoid CB(1) receptors was intact in the striatum of BC1 knock-out (KO) mice despite D(2) and CB(1) receptors mediated similar electrophysiological actions. Interestingly, the fragile X mental retardation protein FMRP, one of the multiple BC1 partners, is not involved in the BC1 effects on the D(2)-mediated transmission. Because D(2)DR mRNA is apparently equally translated in the BC1-KO and wild-type mice, whereas the protein level is higher in BC1-KO mice, we suggest that BC1 RNA controls D(2)DR indirectly, probably regulating translation of molecules involved in D(2)DR turnover and/or stability.
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MESH Headings
- Animals
- Animals, Newborn
- Biphenyl Compounds/pharmacology
- Cells, Cultured
- Corpus Striatum/cytology
- Dopamine D2 Receptor Antagonists
- Glutamate Decarboxylase/metabolism
- Guanosine 5'-O-(3-Thiotriphosphate)/pharmacokinetics
- In Vitro Techniques
- Inhibitory Postsynaptic Potentials/drug effects
- Inhibitory Postsynaptic Potentials/physiology
- Isoenzymes/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microtubule-Associated Proteins/metabolism
- Neurons/drug effects
- Neurons/physiology
- Oligonucleotides/pharmacology
- Patch-Clamp Techniques/methods
- Piperazines/pharmacology
- RNA, Long Noncoding
- RNA, Messenger/biosynthesis
- RNA, Untranslated
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/chemistry
- Receptors, Dopamine D2/physiology
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Ribonucleoproteins, Small Cytoplasmic/deficiency
- Ribonucleoproteins, Small Cytoplasmic/physiology
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- Diego Centonze
- Clinica Neurologica, Dipartimento di Neuroscienze
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Silvia Rossi
- Clinica Neurologica, Dipartimento di Neuroscienze
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Ilaria Napoli
- Dipartimento di Biologia, and
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Valentina Mercaldo
- Dipartimento di Biologia, and
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Caroline Lacoux
- Dipartimento di Biologia, and
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Francesca Ferrari
- Dipartimento di Biologia, and
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Maria Teresa Ciotti
- Dipartimento di Biologia, and
- Consiglio Nazionale delle Ricerche/CERC, 00143 Rome, Italy
| | - Valentina De Chiara
- Clinica Neurologica, Dipartimento di Neuroscienze
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Chiara Prosperetti
- Clinica Neurologica, Dipartimento di Neuroscienze
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Mauro Maccarrone
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
- Dipartimento di Scienze Biomediche Comparate, Università degli Studi di Teramo, 64100 Teramo, Italy, and
| | - Filomena Fezza
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Università Tor Vergata, 00133 Rome, Italy
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Paolo Calabresi
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
- Clinica Neurologica, Università di Perugia, Ospedale Silvestrini, 06156 Perugia, Italy
| | - Giorgio Bernardi
- Clinica Neurologica, Dipartimento di Neuroscienze
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
| | - Claudia Bagni
- Dipartimento di Biologia, and
- Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC), 00143 Rome, Italy
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21
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Dean I, Robertson SJ, Edwards FA. Serotonin drives a novel GABAergic synaptic current recorded in rat cerebellar purkinje cells: a Lugaro cell to Purkinje cell synapse. J Neurosci 2003; 23:4457-69. [PMID: 12805286 PMCID: PMC6740807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
We recorded a novel fast GABAergic synaptic current in cerebellar Purkinje cells in rat brain slices using patch-clamp techniques. Because of a relatively low sensitivity to bicuculline, these currents can be recorded under conditions in which basket and stellate cell inputs are blocked. The observations that the novel synaptic currents occur spontaneously only in the presence of serotonin, and the specific limited positions in the slice from which they can be electrically evoked, suggest that the presynaptic cell is the Lugaro cell. Cell-attached recordings confirm that the Lugaro cell is the only interneuron in the cerebellar cortex with firing behavior consistent with the spontaneous activity recorded in Purkinje cells. The input shows a strong presynaptic modulation mediated by GABA(A) receptors, resulting in a dynamic range from almost 0 to >90% release probability. Modeling GABA(A) receptor responses to different GABA transients suggests that the relatively low sensitivity of the synaptic currents to bicuculline, compared with the higher affinity GABA(A) receptor antagonist SR-95531 (2-(3-carboxypropyl)-3-amino-6-(4-methoxyphenyl) pyridazinium), is attributable to an unusually long GABA dwell time and/or high GABA concentration in the synaptic cleft. The significance of this novel input is discussed in relation to other GABAergic synapses impinging on Purkinje cells. We suggest that the release of GABA onto Purkinje cells from Lugaro cells would primarily occur during motor activity under conditions in which the activity of basket and stellate cells might be inhibited.
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Affiliation(s)
- Isabel Dean
- Department of Physiology, University College London, London WC1E 6BT, United Kingdom
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22
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Overstreet LS, Westbrook GL. Synapse density regulates independence at unitary inhibitory synapses. J Neurosci 2003; 23:2618-26. [PMID: 12684447 PMCID: PMC6742076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Neurotransmitter transporters may promote synapse specificity by limiting spillover between release sites. At GABAergic synapses, transport block prolongs synaptic responses when many inputs are activated, yet it is unclear whether transporters alter signaling by single axons. We found that unitary IPSCs generated by paired recordings between hippocampal interneurons and granule cells could be either prolonged or totally unaffected by block of GABA transporters. This variability was explained by the density of active release sites rather than the number of active sites. Prolongation by transport block required release from multiple sites and was enhanced by repetitive activation. Furthermore, transport-sensitive unitary IPSCs were accelerated when the release probability was reduced, indicating that cross talk prolonged the time course of IPSCs even when transport was intact. Our results suggest that the release site density regulates the degree of cross talk as well as the contribution of transporters to GABA clearance. Thus, interplay between release site density and transporter action determines the independence of unitary inhibitory synapses.
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Affiliation(s)
- Linda S Overstreet
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97201, USA.
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23
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Liu RJ, van den Pol AN, Aghajanian GK. Hypocretins (orexins) regulate serotonin neurons in the dorsal raphe nucleus by excitatory direct and inhibitory indirect actions. J Neurosci 2002; 22:9453-64. [PMID: 12417670 PMCID: PMC6758063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2002] [Revised: 06/24/2002] [Accepted: 06/28/2002] [Indexed: 02/27/2023] Open
Abstract
The hypocretins (hcrt1 and hcrt2) are expressed by a discrete population of hypothalamic neurons projecting to many regions of the CNS, including the dorsal raphe nucleus (DRN), where serotonin (5-HT) neurons are concentrated. In this study, we investigated responses to hcrts in 216 physiologically identified 5-HT and non-5-HT neurons of the DRN using intracellular and whole-cell recording in rat brain slices. Hcrt1 and hcrt2 induced similar amplitude and dose-dependent inward currents in most 5-HT neurons tested (EC50, approximately 250 nm). This inward current was not blocked by the fast Na+ channel blocker TTX or in a Ca2+-free solution, indicating a direct postsynaptic action. The hcrt-induced inward current reversed near -18 mV and was primarily dependent on external Na+ but not on external or internal Ca2+, features typical of Na+/K+ nonselective cation channels. At higher concentrations, hcrts also increased spontaneous postsynaptic currents in 5-HT neurons (EC50, approximately 450-600 nm), which were TTX-sensitive and mostly blocked by the GABA(A) antagonist bicuculline, indicating increased impulse flow in local GABA interneurons. Accordingly, hcrts were found to increase the basal firing of presumptive GABA interneurons. Immunolabeling showed that hcrt fibers projected to both 5-HT and GABA neurons in the DRN. We conclude that hcrts act directly to excite 5-HT neurons primarily via a TTX-insensitive, Na+/K+ nonselective cation current, and indirectly to activate local inhibitory GABA inputs to 5-HT cells. The greater potency of hcrts in direct excitation compared with indirect inhibition suggests a negative feedback function for the latter at higher levels of hcrt activity.
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Affiliation(s)
- Rong-Jian Liu
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut 06508, USA.
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24
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Telgkamp P, Raman IM. Depression of inhibitory synaptic transmission between Purkinje cells and neurons of the cerebellar nuclei. J Neurosci 2002; 22:8447-57. [PMID: 12351719 PMCID: PMC6757792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
Neurons of the cerebellar nuclei have basal firing rates of 10-20 Hz, despite the convergence of many GABAergic Purkinje terminals onto cerebellar nuclear somata and the high spontaneous firing rate of Purkinje neurons. This persistence of firing during a constant barrage of inhibition raises the question of what patterns of Purkinje cell input inhibit nuclear cells most effectively. To explore the hypothesis that synaptic depression moderates inhibition at this synapse, we made whole-cell recordings from cerebellar nuclear neurons in mouse brain slices. IPSCs and IPSPs were elicited by electrically stimulating the corticonuclear tract at 10, 50, and 100 Hz. IPSCs evoked at the mean spontaneous firing rate of Purkinje cells (50 Hz) depressed by approximately 60%. The onset of depression had a fast, frequency-dependent component, from which recovery was rapid (approximately 100 msec), and a slower, frequency-independent component, from which recovery was slow (approximately 10 sec). As stimulation rate increased, steady-state depression increased, but each IPSC decayed less completely between stimuli, producing a "tonic" IPSC. Changes in stimulation rate produced rapid changes in the level of depression. Under current clamp, cerebellar nuclear neurons fired spontaneously. During 50 Hz trains of IPSPs, firing was initially interrupted, but resumed coincident with the onset of depression. Low-frequency trains entrained postsynaptic firing, and high-frequency trains greatly slowed firing, primarily because of the tonic IPSC. Thus, the properties of depression at this synapse appear to limit the sensitivity of nuclear cells to basal inhibition, while allowing the cells to respond to increases and decreases in Purkinje cell activity.
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Affiliation(s)
- Petra Telgkamp
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA
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25
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Morales B, Choi SY, Kirkwood A. Dark rearing alters the development of GABAergic transmission in visual cortex. J Neurosci 2002; 22:8084-90. [PMID: 12223562 PMCID: PMC6758086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
We studied the role of sensory experience in the maturation of GABAergic circuits in the rat visual cortex. Between the time at which the eyes first open and the end of the critical period for experience-dependent plasticity, the total GABAergic input converging into layer II/III pyramidal cells increases threefold. We propose that this increase reflects changes in the number of quanta released by presynaptic axons. Here, we show that the developmental increase in GABAergic input is prevented in animals deprived of light since birth but not in animals deprived of light after a period of normal experience. Thus, sensory experience appears to play a permissive role in the maturation of intracortical GABAergic circuits.
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Affiliation(s)
- Bernardo Morales
- Mind Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218, USA
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26
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Abstract
The effects of aconitine, an Aconitum alkaloid, on spontaneous inhibitory and excitatory postsynaptic currents (IPSCs and EPSCs respectively) were investigated in the mechanically dissociated rat ventromedial hypothalamic (VMH) neurons in which native presynaptic nerve terminals remained intact. Under current-clamp conditions, aconitine (3 x 10(-6) M) depolarized the neuron with generating the action potentials. The aconitine-induced depolarization was markedly suppressed in the presence of CNQX but it was facilitated in the presence of bicuculline, suggesting that release of excitatory and inhibitory neurotransmitters may be involved in the aconitine action in addition to its direct action on postsynaptic membrane. Under the voltage-clamp conditions, aconitine reversibly increased the frequency of spontaneous IPSC and EPSC frequency, but it did not alter their amplitude distribution. Tetrodotoxin (TTX, 3 x 10(-7) M) completely abolished the aconitine action on spontaneous IPSC frequency. Likewise removal of extracellular Na(+) completely suppressed the aconitine action. Both Ca(2+)-free external solution or addition of 10(-4) M Cd(2+) to normal solutions eliminated the facilitatory effect of aconitine on the IPSC frequency. Overall these results suggest that aconitine depolarizes the presynaptic membrane by activating voltage-dependent Na(+) channels. Increase of intraterminal Ca(2+) concentration via an activation of voltage-dependent Ca(2+) channels in turn enhances the spontaneous transmitter release from presynaptic nerve terminals. The presynaptic action of aconitine may play a crucial role for membrane excitability of rat VMH neurons.
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Affiliation(s)
- Hisashi Yamanaka
- Cellular and System Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Atsushi Doi
- Cellular and System Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hitoshi Ishibashi
- Cellular and System Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Norio Akaike
- Cellular and System Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
- Author for correspondence:
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27
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Mannaioni G, Marino MJ, Valenti O, Traynelis SF, Conn PJ. Metabotropic glutamate receptors 1 and 5 differentially regulate CA1 pyramidal cell function. J Neurosci 2001; 21:5925-34. [PMID: 11487615 PMCID: PMC6763150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2001] [Revised: 05/15/2001] [Accepted: 05/31/2001] [Indexed: 02/21/2023] Open
Abstract
The activation of group I metabotropic glutamate receptors (mGluRs) produces a variety of actions that lead to alterations in excitability and synaptic transmission in the CA1 region of the hippocampus. The group I mGluRs, mGluR1 and mGluR5, are activated selectively by (S)-3,5-dihydroxyphenylglycine (DHPG). To identify which of these mGluR subtypes are responsible for the various actions of DHPG in area CA1, we took advantage of two novel subtype-selective antagonists. (S)-(+)-alpha-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist that is selective for mGluR5. The use of these compounds in experiments with whole-cell patch-clamp recording and Ca(2+)-imaging techniques revealed that each group I mGluR subtype plays distinct roles in regulating the function of CA1 pyramidal neurons. The block of mGluR1 by LY367385 suppressed the DHPG-induced increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) and the direct depolarization of CA1 hippocampal neurons. In addition, the increase in the frequency of spontaneous IPSCs (sIPSCs) caused by the DHPG-induced depolarization of inhibitory interneurons also was blocked by LY367385, as was the DHPG-induced inhibition of transmission at the Schaffer collateral-->CA1 synapse. On the other hand, the block of mGluR5 by MPEP antagonized the DHPG-induced suppression of the Ca(2+)-activated potassium current (I(AHP)) and potentiation of the NMDA receptor. Finally, antagonism of the DHPG-induced suppression of evoked IPSCs required the blockade of both mGluR1 and mGluR5. These data suggest that mGluR1 and mGluR5 play distinct roles in the regulation of the excitability of hippocampal CA1 pyramidal neurons.
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Affiliation(s)
- G Mannaioni
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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28
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Ali AB, Rossier J, Staiger JF, Audinat E. Kainate receptors regulate unitary IPSCs elicited in pyramidal cells by fast-spiking interneurons in the neocortex. J Neurosci 2001; 21:2992-9. [PMID: 11312283 PMCID: PMC6762560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Unitary IPSCs elicited by fast-spiking (FS) interneurons in layer V pyramidal cells of the neocortex were studied by means of dual whole-cell recordings in acute slices. FS to pyramidal cell unitary IPSCs were depressed by (RS)-S-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) (ATPA), a kainate (KA) receptor agonist, and by the endogenous agonist l-glutamate in the presence of AMPA, NMDA, mGluR, and GABA(B) receptor antagonists. This effect was accompanied by an increase in failure rate of synaptic transmission, in the coefficient of variation, and in the paired pulse ratio, indicating a presynaptic origin of the IPSC depression. Pairing the activation of the presynaptic neuron with a depolarization of the postsynaptic cell mimicked the decrease of unitary IPSCs, and this effect persisted when postsynaptic sodium action potentials were blocked with the local anesthetic QX314. The effects of ATPA, glutamate, and of the pairing protocol were almost totally blocked by CNQX. These data suggest that KA receptors located on presynaptic FS cell terminals decrease the release of GABA and can be activated by glutamate released from the somatodendritic compartment of the postsynaptic pyramidal cells.
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Affiliation(s)
- A B Ali
- Laboratoire de Neurobiologie et Diversité Cellulaire, Centre National de la Recherche Scientifique, Unité Mixte Recherche 7637, ESPCI, 75231, Paris, Cedex 5, France.
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29
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Wong TP, Marchese G, Casu MA, Ribeiro-da-Silva A, Cuello AC, De Koninck Y. Loss of presynaptic and postsynaptic structures is accompanied by compensatory increase in action potential-dependent synaptic input to layer V neocortical pyramidal neurons in aged rats. J Neurosci 2000; 20:8596-606. [PMID: 11069968 PMCID: PMC6773180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Reduction in both presynaptic and postsynaptic structures in the aging neocortex may significantly affect functional synaptic properties in this area. To directly address this issue, we combined whole-cell patch-clamp recording of spontaneously occurring postsynaptic currents (PSCs) with morphological analysis of layer V pyramidal neurons in the parietal cortex of young adult (1- to 2-month-old) and aged (28- to 37-month-old) BN x F344 F(1) hybrid rats. Analysis of spontaneous PSCs was used to contrast functional properties of basal synaptic input with structural alterations in the dendritic tree of pyramidal neurons and density of terminals in contact with these cells. We observed significant changes in a number of morphological parameters of pyramidal neurons in aged rats. These include smaller cell body size and fewer basal dendritic branches (but not of oblique dendrites and dendritic tufts) and spines. Ultrastructural analysis also revealed a lower density of presynaptic terminals per unit length of postsynaptic membrane of labeled pyramidal neurons in the aged brain. This reduction in both presynaptic and postsynaptic elements was paralleled by a significant decrease in frequency of tetrodotoxin-insensitive miniature (action potential-independent) PSCs (mPSCs). The frequency of excitatory and inhibitory mPSCs was reduced to the same extent. In contrast, no significant change was observed in the frequency of spontaneous PSCs recorded in absence of tetrodotoxin (sPSCs), indicating an increase in action potential-dependent (frequency(sPSCs) - frequency(mPSCs)) input to pyramidal neurons in the aged group. This functional compensation may explain the lack of drastic loss of spontaneous neuronal activity in normal aging.
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Affiliation(s)
- T P Wong
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada, H3G 1Y6
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30
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Nishikawa K, MacIver MB. Membrane and synaptic actions of halothane on rat hippocampal pyramidal neurons and inhibitory interneurons. J Neurosci 2000; 20:5915-23. [PMID: 10934238 PMCID: PMC6772580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
A relatively small number of inhibitory interneurons can control the excitability and synchronization of large numbers of pyramidal neurons in hippocampus and other cortical regions. Thus, anesthetic modulation of interneurons could play an important role during anesthesia. The aim of this study was to investigate effects of a general anesthetic, halothane, on membrane and synaptic properties of rat hippocampal interneurons. GABA receptor-mediated IPSCs were recorded with whole-cell patch-clamp techniques in visually identified CA1 pyramidal cells and interneurons located at the border of stratum lacunosum-moleculare and stratum radiatum. Halothane (0.35 mm congruent with 1.2 vol%) depressed evoked IPSC amplitudes recorded from both pyramidal cells and inhibitory interneurons. Also, halothane considerably prolonged the decay time constant of evoked IPSCs in pyramidal cells and interneurons. The frequencies of miniature IPSCs were increased by halothane (two- to threefold) in both types of neuron. On the other hand, halothane effects on resting membrane potentials were variable but minimal in both types of neurons. In current-clamp recordings, halothane depressed EPSP amplitudes and increased IPSP amplitudes recorded from both types of neurons. In addition, halothane increased the failure rate of synaptically evoked action potentials. Taken together, these data provide evidence that halothane increases GABA(A) receptor-mediated synaptic inhibition between synaptically connected interneurons and depresses excitatory transmission, similar to effects observed in pyramidal neurons.
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Affiliation(s)
- K Nishikawa
- Neuropharmacology Laboratory, Department of Anesthesia, Stanford University School of Medicine, Stanford, California 94305-5117, USA.
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31
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Hugel S, Schlichter R. Presynaptic P2X receptors facilitate inhibitory GABAergic transmission between cultured rat spinal cord dorsal horn neurons. J Neurosci 2000; 20:2121-30. [PMID: 10704486 PMCID: PMC6772506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The superficial layers of the spinal cord dorsal horn (DH) express P2X2, P2X4, and P2X6 subunits entering into the formation of ionotropic (P2X) receptors for ATP. Using a culture system of laminae I-III from neonatal rat DH, we show that ATP induced a fast nonselective cation current in 38% of the neurons (postsynaptic effect). ATP also increased the frequency of miniature IPSCs (mIPSCs) mediated by GABA(A) receptors or by glycine receptors in 22 and 9%, respectively, of the neurons tested (presynaptic effect) but had no effect on glutamatergic transmission. The presynaptic effect of ATP on GABAergic transmission was not significantly affected by thapsigargin (1 microM) but was completely dependent on Ca(2+) influx. Presynaptic and postsynaptic effects were inhibited by suramin, pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid, and reactive blue and were not reproduced by uridine 5'-triphosphate (UTP) or adenosine 5'-O-(2-thiodiphosphate) (ADP-beta-S), suggesting the implication of ionotropic P2X rather than of metabotropic P2Y receptors. alphabeta-methylene-ATP (100 microM) did not reproduce the effects of ATP. ATP reversibly increased the amplitude of electrically evoked GABAergic IPSCs and reduced paired-pulse inhibition or facilitation without affecting IPSC kinetics. This effect was preferentially, but not exclusively, observed in neurons coreleasing ATP and GABA. We conclude that in cultured DH neurons, the effects of ATP are mediated by P2X receptors having a pharmacological profile dominated by the P2X2 subunit. The presynaptic receptors might underlie a modulatory action of ATP on a subset of GABAergic interneurons involved in the spinal processing of nociceptive information.
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Affiliation(s)
- S Hugel
- Laboratoire de Neurophysiologie Cellulaire et Intégrée, Unité Mixte de Recherche 7519-Centre National de la Recherche Scientifique, Université Louis Pasteur, 67084 Strasbourg Cedex, France
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32
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Chergui K, Bouron A, Normand E, Mulle C. Functional GluR6 kainate receptors in the striatum: indirect downregulation of synaptic transmission. J Neurosci 2000; 20:2175-82. [PMID: 10704492 PMCID: PMC6772511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/1999] [Revised: 12/30/1999] [Accepted: 01/05/2000] [Indexed: 02/15/2023] Open
Abstract
Kainate receptors (KARs) are abundantly expressed in the basal ganglia, but their function in synaptic transmission has not been established. In the present study, we show that the GluR6 subunit of KARs is expressed in both substance P- and enkephalin-containing GABAergic projection neurons of the mouse striatum. Using whole-cell voltage-clamp recordings in brain slices, we demonstrate the presence of functional KARs in the dorsal striatum activated by low concentrations of the AMPA/KAR agonist domoate in wild-type but not GluR6-deficient mice. Despite the abundance of KARs, we found no evidence for synaptic activation of these receptors after single or repetitive stimulation of glutamatergic afferents. Domoate induces a transient increase in the frequency of spontaneous IPSCs of small amplitude and a sustained depression of large IPSCs evoked by minimal electrical stimulation within the striatum in wild-type mice but not in GluR6-deficient mice. This depressant effect is inhibited in presence of adenosine A(2A) receptor antagonists, ZM-241385 and SCH-58261. These data strongly suggest that, in striatal neurons, KARs depress GABAergic synaptic transmission indirectly via release of adenosine acting on A(2A) receptors.
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Affiliation(s)
- K Chergui
- Centre National de la Recherche Scientifique, Unite Mixte Recherche 5091, Université Victor Segalen-Bordeaux II, 33076 Bordeaux Cedex, France
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33
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Okada M, Onodera K, Van Renterghem C, Sieghart W, Takahashi T. Functional correlation of GABA(A) receptor alpha subunits expression with the properties of IPSCs in the developing thalamus. J Neurosci 2000; 20:2202-8. [PMID: 10704495 PMCID: PMC6772493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
GABA(A) receptor alpha1 and alpha2 subunits are expressed differentially with ontogenic period in the brain, but their functional roles are not known. We have recorded GABA(A) receptor-mediated IPSCs from laterodorsal (LD) thalamic relay neurons in slices of rat brain at various postnatal ages and found that decay times of evoked IPSCs and spontaneous miniature IPSCs undergo progressive shortening during the first postnatal month. With a similar time course, expression of transcripts and proteins of GABA(A) receptor alpha2 subunit in LD thalamic region declined, being replaced by those of alpha1 subunit. To further address the causal relationship between alpha subunits and IPSC decay time kinetics, we have overexpressed GABA(A) receptor alpha1 subunit together with green fluorescent protein in LD thalamic neurons in organotypic culture using recombinant Sindbis virus vectors. Miniature IPSCs recorded from the LD thalamic neurons overexpressed with alpha1 subunit had significantly faster decay time compared with control expressed with beta-galactosidase. We conclude that the alpha2-to-alpha1 subunit switch underlies the developmental speeding in the decay time of GABAergic IPSCs.
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Affiliation(s)
- M Okada
- Department of Neurophysiology, University of Tokyo Faculty of Medicine, Tokyo 113-0033, Japan
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Varela JA, Song S, Turrigiano GG, Nelson SB. Differential depression at excitatory and inhibitory synapses in visual cortex. J Neurosci 1999; 19:4293-304. [PMID: 10341233 PMCID: PMC6782599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The function of cortical circuits depends critically on the balance between excitation and inhibition. This balance reflects not only the relative numbers of excitatory and inhibitory synapses but also their relative strengths. Recent studies of excitatory synapses in visual and somatosensory cortices have emphasized that synaptic strength is not a fixed quantity but is a dynamic variable that reflects recent presynaptic activity. Here, we compare the dynamics of synaptic transmission at excitatory and inhibitory synapses onto visual cortical pyramidal neurons. We find that inhibitory synapses show less overall depression than excitatory synapses and that the kinetics of recovery from depression also differ between the two classes of synapse. When excitatory and inhibitory synapses are stimulated concurrently, this differential depression produces a time- and frequency-dependent shift in the reversal potential of the composite postsynaptic current. These results indicate that the balance between excitation and inhibition can change dynamically as a function of activity.
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Affiliation(s)
- J A Varela
- Department of Biology and Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02254, USA
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Hill MW, Reddy PA, Covey DF, Rothman SM. Contribution of subsaturating GABA concentrations to IPSCs in cultured hippocampal neurons. J Neurosci 1998; 18:5103-11. [PMID: 9651194 PMCID: PMC6793480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/1998] [Revised: 04/08/1998] [Accepted: 04/24/1998] [Indexed: 02/08/2023] Open
Abstract
The time course of EPSCs and IPSCs is at least partly determined by the concentration profile of neurotransmitter acting on postsynaptic receptors. Several recent reports have suggested that the peak synaptic cleft concentration of the inhibitory neurotransmitter GABA likely reaches at least 500 microM, a level that saturates the GABAA receptor. In the course of investigating the experimental anticonvulsant 3,3-diethyl-2-pyrrolidinone (diethyl-lactam), we have observed an important contribution to IPSC decay by subsaturating concentrations of GABA. Diethyl-lactam augments currents elicited by the exogenous application of subsaturating concentrations of GABA in voltage-clamped, cultured hippocampal neurons and significantly prolongs the decay of autaptic IPSCs and miniature IPSCs in our cultures. In addition, diethyl-lactam potentiates currents in excised outside-out membrane patches elicited by the prolonged application of low concentrations of GABA. However, when patches are exposed to 1-2 msec pulses of 1 mM GABA, diethyl-lactam does not alter current decay. Tiagabine, which blocks GABA reuptake, does not prolong IPSCs, so it is unlikely that uptake inhibition accounts for the enhancement of IPSCs. EPSCs and miniature IPSC frequency are unaffected by diethyl-lactam, again consistent with a postsynaptic site of action. We propose that during an IPSC, a substantial number of postsynaptic receptors must be exposed to subsaturating concentrations of GABA. A simplified model of GABAA receptor kinetics can account for the effects of diethyl-lactam on exogenous GABA and IPSCs if diethyl-lactam has its main effect on the monoliganded states of the GABAA receptor.
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Affiliation(s)
- M W Hill
- Departments of Neurology and Neurosurgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Banks MI, Li TB, Pearce RA. The synaptic basis of GABAA,slow. J Neurosci 1998; 18:1305-17. [PMID: 9454840 PMCID: PMC6792721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although two kinetically distinct evoked GABAA responses (GABAA,fast and GABAA,slow) have been observed in CA1 pyramidal neurons, studies of spontaneous IPSCs (sIPSCs) in these neurons have reported only a single population of events that resemble GABAA,fast in their rise and decay kinetics. The absence of slow sIPSCs calls into question the synaptic basis of GABAA,slow. We present evidence here that both evoked responses are synaptic in origin, because two classes of minimally evoked, spontaneous and miniature IPSCs exist that correspond to GABAA,fast and GABAA,slow. Slow sIPSCs occur infrequently, suggesting that the cells underlying these events have a low spontaneous firing rate, unlike the cells giving rise to fast sIPSCs. Like evoked GABAA,fast and GABAA,slow, fast and slow sIPSCs are modulated differentially by furosemide, a subtype-specific GABAA antagonist. Furosemide blocks fast IPSCs by acting directly on the postsynaptic receptors, because it reduces the amplitude of both miniature IPSCs and the responses of excised patches to applied GABA. Thus, in the hippocampus, parallel inhibitory circuits are composed of separate populations of interneurons that contact anatomically segregated and pharmacologically distinct postsynaptic receptors.
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Affiliation(s)
- M I Banks
- Anesthesiology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Zhu WJ, Vicini S. Neurosteroid prolongs GABAA channel deactivation by altering kinetics of desensitized states. J Neurosci 1997; 17:4022-31. [PMID: 9151718 PMCID: PMC6573570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Fast applications of GABA (1 mM) to nucleated and outside-out patches excised from granule neurons in cerebellar slices from developing rats evoked currents with a double exponential time course reminiscent of that of IPSCs. A neurosteroid 3alpha, 21dihydroxy-5alpha-pregnan-20-one (THDOC) remarkably increased the slow deactivation time constant and slowed down recovery from desensitization, as estimated by paired-pulse GABA applications. THDOC also reduced the amplitude of GABA currents, whereas it failed to affect the fast deactivation component and its relative contribution to peak amplitude. The effects of THDOC on slow deactivation were greater in rats younger than postnatal day 13 (P13) as compared with rats at P30-P35. THDOC failed to alter deactivation of short responses induced by a less-potent agonist taurine at saturating doses. These responses had deactivation kinetics described by a fast single exponential decay, little desensitization, and quick recovery. However, THDOC slowed deactivation if taurine responses were long enough to allow consistent desensitization, suggesting that desensitized states are required for the neurosteroid to modulate GABA responses. In outside-out patches, just as desensitized states prolonged GABA responses by producing reopening of channels activated by brief GABA pulses, THDOC increased the channel open probability by further increasing the number of late channel openings, resulting in a prolongation of the slow deactivation. Our data suggest that neurosteroid potentiates the inhibitory postsynaptic transmission via the prolongation of the slow deactivation and that the alteration of kinetics of entry and exit from desensitized states underlies the allosteric modification of GABAA receptors by neurosteroids.
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Affiliation(s)
- W J Zhu
- Department of Physiology and Biophysics, Georgetown University School of Medicine, Washington, DC 20007, USA
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Morishita W, Kirov SA, Pitler TA, Martin LA, Lenz RA, Alger BE. N-ethylmaleimide blocks depolarization-induced suppression of inhibition and enhances GABA release in the rat hippocampal slice in vitro. J Neurosci 1997; 17:941-50. [PMID: 8994049 PMCID: PMC6573169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Regulation of synaptic, GABAA receptor-mediated inhibition is a process of critical importance to normal brain function. Recently, we have described a phenomenon in hippocampus of a transient, yet marked, decrease in spontaneous, GABAA receptor-mediated IPSCs after depolarization activated Ca2+ influx into a pyramidal cell. This process, depolarization-induced suppression of inhibition (DSI), is absent in hippocampal cells that previously had been exposed to pertussis toxin in vivo, implicating a G-protein in the DSI process. To circumvent the problem that a single cell cannot be studied before and after G-protein block using the pertussis toxin pretreatment method, we have used the sulfhydryl alkylating agent N-ethylmaleimide (NEM), which blocks pertussis toxin-sensitive G-proteins, to determine whether acute inhibition of G-proteins can eliminate DSI of spontaneous IPSCs (sIPSCs). In whole-cell recordings from CA1 pyramidal cells that were first determined to express DSI, we have found that NEM does block DSI of sIPSCs. We also report that DSI of monosynaptic, evoked IPSCs is blocked by NEM, suggesting that a similar mechanism underlies both forms of DSI. It was of interest that DSI was abolished at a time when NEM had increased, not decreased, GABA transmission. Indeed, NEM greatly increased quantal GABA release by a Ca(2+)-independent mechanism, an observation with potentially important implications for understanding synaptic GABA release.
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Affiliation(s)
- W Morishita
- Department of Physiology, University of Maryland School of Medicine, Baltimore 21201, USA
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Warren CR, Cowan CA. [Leukocyte count of puerperal sows]. Berl Munch Tierarztl Wochenschr 1996; 109:330-5. [PMID: 9054332 PMCID: PMC5828525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
147 blood samples of postparturient sows of a secluded housing were taken. The samples were conserved with ACD-solution. The influence of the number and week of the lactation and the health of the sow, determined by puerperal diseases was studied. Hematological values of healthy postparturient sows are: leucocytes 12.6 +/- 2.2 G/l; basophile granulocytes 0.1 +/- 0.1 G/l, eosinophile granulocytes 0.5 +/- 0.4 G/l; banded neutrophile granulocytes 1.3 +/- 0.6 G/l, segmented neutrophile granulocytes 5.2 +/- 1.4 G/l; lymphocytes 5.5 +/- 1.4 G/l, monocytes 0.3 +/- 0.3 G/l. The leucocyte number is lower in the investigated herd compared with quotations in the literature. This is based on the good health conditions in the herd. Changes due to the number and week of the lactation have no clinical relevance. Health status, here described by puerperal diseases is the significant influencing factor of the leucocyte number. The severity of puerperal diseases is significant. Due to puerperal diseases the leucocyte number rises quickly after a short drop about 2 G/l. The number of the neutrophile granulocytes increases, but the lymphocyte number is reduced at the beginning of the illness. The application of ACD-solution for stabilizing of great amounts of blood samples under practical conditions is demonstrated. It is possible to stabilize pigs blood well.
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Affiliation(s)
- Curtis R. Warren
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Chad A. Cowan
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
- Broad Institute, Cambridge, Massachusetts 02142, USA
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