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Belair DG, Visconti RJ, Hong M, Marella M, Peters MF, Scott CW, Kolaja KL. Human ileal organoid model recapitulates clinical incidence of diarrhea associated with small molecule drugs. Toxicol In Vitro 2020; 68:104928. [PMID: 32622998 DOI: 10.1016/j.tiv.2020.104928] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/08/2020] [Accepted: 06/30/2020] [Indexed: 12/27/2022]
Abstract
Drug-induced gastrointestinal toxicity (GIT) is a common treatment-emergent adverse event that can negatively impact dosing, thereby limiting efficacy and treatment options for patients. An in vitro assay of GIT is needed to address patient variability, mimic the microphysiology of the gut, and accurately predict drug-induced GIT. Primary human ileal organoids (termed 'enteroids') have proven useful for stimulating intestinal stem cell proliferation and differentiation to multiple cell types present in the gut epithelium. Enteroids have enabled characterization of gut biology and the signaling involved in the pathogenesis of disease. Here, enteroids were differentiated from four healthy human donors and assessed for culture duration-dependent differentiation status by immunostaining for gut epithelial markers lysozyme, chromogranin A, mucin, and sucrase isomaltase. Differentiated enteroids were evaluated with a reference set of 31 drugs exhibiting varying degrees of clinical incidence of diarrhea, a common manifestation of GIT that can be caused by drug-induced thinning of the gut epithelium. An assay examining enteroid viability in response to drug treatment demonstrated 90% accuracy for recapitulating the incidence of drug-induced diarrhea. The human enteroid viability assay developed here presents a promising in vitro model for evaluating drug-induced diarrhea.
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Affiliation(s)
- David G Belair
- Investigative Toxicology, Nonclinical Development, Celgene Corporation, Summit, NJ, USA
| | - Richard J Visconti
- Investigative Toxicology, Nonclinical Development, Celgene Corporation, Summit, NJ, USA
| | - Miyoun Hong
- Investigative Toxicology, Nonclinical Development, Celgene Corporation, Summit, NJ, USA
| | - Mathieu Marella
- Histology and Pathology, Nonclinical Development, Celgene Corporation, Summit, NJ, USA
| | - Matthew F Peters
- Oncology Safety, BioPharmaceuticals R&D, AstraZeneca, Boston, MA, USA
| | - Clay W Scott
- Oncology Safety, BioPharmaceuticals R&D, AstraZeneca, Boston, MA, USA
| | - Kyle L Kolaja
- Investigative Toxicology, Nonclinical Development, Celgene Corporation, Summit, NJ, USA.
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2
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Peters MF, Choy AL, Pin C, Leishman DJ, Moisan A, Ewart L, Guzzie-Peck PJ, Sura R, Keller DA, Scott CW, Kolaja KL. Developing in vitro assays to transform gastrointestinal safety assessment: potential for microphysiological systems. Lab Chip 2020; 20:1177-1190. [PMID: 32129356 DOI: 10.1039/c9lc01107b] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Drug-induced gastrointestinal toxicities (DI-GITs) are among the most common adverse events in clinical trials. High prevalence of DI-GIT has persisted among new drugs due in part to the lack of robust experimental tools to allow early detection or to guide optimization of safer molecules. Developing in vitro assays for the leading GI toxicities (nausea, vomiting, diarrhoea, constipation, and abdominal pain) will likely involve recapitulating complex physiological properties that require contributions from diverse cell/tissue types including epithelial, immune, microbiome, nerve, and muscle. While this stipulation may be beyond traditional 2D monocultures of intestinal cell lines, emerging 3D GI microtissues capture interactions between diverse cell and tissue types. These interactions give rise to microphysiologies fundamental to gut biology. For GI microtissues, organoid technology was the breakthrough that introduced intestinal stem cells with the capability of differentiating into each of the epithelial cell types and that self-organize into a multi-cellular tissue proxy with villus- and crypt-like domains. Recently, GI microtissues generated using miniaturized devices with microfluidic flow and cyclic peristaltic strain were shown to induce Caco2 cells to spontaneously differentiate into each of the principle intestinal epithelial cell types. Second generation models comprised of epithelial organoids or microtissues co-cultured with non-epithelial cell types can successfully reproduce cross-'tissue' functional interactions broadening the potential of these models to accurately study drug-induced toxicities. A new paradigm in which in vitro assays become an early part of GI safety assessment could be realized if microphysiological systems (MPS) are developed in alignment with drug-discovery needs. Herein, approaches for assessing GI toxicity of pharmaceuticals are reviewed and gaps are compared with capabilities of emerging GI microtissues (e.g., organoids, organ-on-a-chip, transwell systems) in order to provide perspective on the assay features needed for MPS models to be adopted for DI-GIT assessment.
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Affiliation(s)
- Matthew F Peters
- Clinical Pharmacology and Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, Boston, USA.
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Peters MF, Landry T, Pin C, Maratea K, Dick C, Wagoner MP, Choy AL, Barthlow H, Snow D, Stevens Z, Armento A, Scott CW, Ayehunie S. Human 3D Gastrointestinal Microtissue Barrier Function As a Predictor of Drug-Induced Diarrhea. Toxicol Sci 2020; 168:3-17. [PMID: 30364994 PMCID: PMC6390652 DOI: 10.1093/toxsci/kfy268] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Drug-induced gastrointestinal toxicities (GITs) rank among the most common clinical side effects. Preclinical efforts to reduce incidence are limited by inadequate predictivity of in vitro assays. Recent breakthroughs in in vitro culture methods support intestinal stem cell maintenance and continual differentiation into the epithelial cell types resident in the intestine. These diverse cells self-assemble into microtissues with in vivo-like architecture. Here, we evaluate human GI microtissues grown in transwell plates that allow apical and/or basolateral drug treatment and 96-well throughput. Evaluation of assay utility focused on predictivity for diarrhea because this adverse effect correlates with intestinal barrier dysfunction which can be measured in GI microtissues using transepithelial electrical resistance (TEER). A validation set of widely prescribed drugs was assembled and tested for effects on TEER. When the resulting TEER inhibition potencies were adjusted for clinical exposure, a threshold was identified that distinguished drugs that induced clinical diarrhea from those that lack this liability. Microtissue TEER assay predictivity was further challenged with a smaller set of drugs whose clinical development was limited by diarrhea that was unexpected based on 1-month animal studies. Microtissue TEER accurately predicted diarrhea for each of these drugs. The label-free nature of TEER enabled repeated quantitation with sufficient precision to develop a mathematical model describing the temporal dynamics of barrier damage and recovery. This human 3D GI microtissue is the first in vitro assay with validated predictivity for diarrhea-inducing drugs. It should provide a platform for lead optimization and offers potential for dose schedule exploration.
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Affiliation(s)
- Matthew F Peters
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
| | - Tim Landry
- MatTek Corporation, Ashland, Massachusetts 01721
| | - Carmen Pin
- Mechanistic Safety and ADME Sciences, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Cambridge, CB4 0WG, UK
| | - Kim Maratea
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
| | - Cortni Dick
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
| | - Matthew P Wagoner
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
| | - Allison L Choy
- Science and Enabling Units IT, AstraZeneca, Waltham, MA 02451
| | - Herb Barthlow
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
| | - Deb Snow
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
| | | | - Alex Armento
- MatTek Corporation, Ashland, Massachusetts 01721
| | - Clay W Scott
- Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, MA 02451
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Lamore SD, Kohnken RA, Peters MF, Kolaja KL. Cardiovascular Toxicity Induced by Kinase Inhibitors: Mechanisms and Preclinical Approaches. Chem Res Toxicol 2019; 33:125-136. [DOI: 10.1021/acs.chemrestox.9b00387] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Sarah D. Lamore
- Preclinical Development, Wave Life Sciences, Lexington, Massachusetts 02421, United States
| | - Rebecca A. Kohnken
- Preclinical Safety, Abbvie, North Chicago, Illinois 60064, United States
| | - Matthew F. Peters
- Oncology Safety, Clinical Pharmacology and Safety Sciences, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, United States
| | - Kyle L. Kolaja
- Investigative Toxicology and Cell Therapy Safety, Nonclinical Development, Celgene Corporation, Summit, New Jersey 07901, United States
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Lamore SD, Ahlberg E, Boyer S, Lamb ML, Hortigon-Vinagre MP, Rodriguez V, Smith GL, Sagemark J, Carlsson L, Bates SM, Choy AL, Stålring J, Scott CW, Peters MF. Deconvoluting Kinase Inhibitor Induced Cardiotoxicity. Toxicol Sci 2018; 158:213-226. [PMID: 28453775 PMCID: PMC5837613 DOI: 10.1093/toxsci/kfx082] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many drugs designed to inhibit kinases have their clinical utility limited by cardiotoxicity-related label warnings or prescribing restrictions. While this liability is widely recognized, designing safer kinase inhibitors (KI) requires knowledge of the causative kinase(s). Efforts to unravel the kinases have encountered pharmacology with nearly prohibitive complexity. At therapeutically relevant concentrations, KIs show promiscuity distributed across the kinome. Here, to overcome this complexity, 65 KIs with known kinome-scale polypharmacology profiles were assessed for effects on cardiomyocyte (CM) beating. Changes in human iPSC-CM beat rate and amplitude were measured using label-free cellular impedance. Correlations between beat effects and kinase inhibition profiles were mined by computation analysis (Matthews Correlation Coefficient) to identify associated kinases. Thirty kinases met criteria of having (1) pharmacological inhibition correlated with CM beat changes, (2) expression in both human-induced pluripotent stem cell-derived cardiomyocytes and adult heart tissue, and (3) effects on CM beating following single gene knockdown. A subset of these 30 kinases were selected for mechanistic follow up. Examples of kinases regulating processes spanning the excitation–contraction cascade were identified, including calcium flux (RPS6KA3, IKBKE) and action potential duration (MAP4K2). Finally, a simple model was created to predict functional cardiotoxicity whereby inactivity at three sentinel kinases (RPS6KB1, FAK, STK35) showed exceptional accuracy in vitro and translated to clinical KI safety data. For drug discovery, identifying causative kinases and introducing a predictive model should transform the ability to design safer KI medicines. For cardiovascular biology, discovering kinases previously unrecognized as influencing cardiovascular biology should stimulate investigation of underappreciated signaling pathways.
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Affiliation(s)
- Sarah D Lamore
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451
| | - Ernst Ahlberg
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, 43153 Mölndal, Sweden
| | - Scott Boyer
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, 43153 Mölndal, Sweden
| | - Michelle L Lamb
- IMED Oncology, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451
| | | | - Victor Rodriguez
- Clyde Bioscience Limited BioCity Scotland, Lanarkshire ML1 5UH, United Kingdom
| | - Godfrey L Smith
- Clyde Bioscience Limited BioCity Scotland, Lanarkshire ML1 5UH, United Kingdom
| | - Johanna Sagemark
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, 43153 Mölndal, Sweden
| | - Lars Carlsson
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, 43153 Mölndal, Sweden
| | - Stephanie M Bates
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Cambridge Science Park, Cambridge, United Kingdom
| | - Allison L Choy
- Research & Development Information, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451
| | - Jonna Stålring
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, 43153 Mölndal, Sweden
| | - Clay W Scott
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451
| | - Matthew F Peters
- Department of Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451
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Scott CW, Zhang X, Abi-Gerges N, Lamore SD, Abassi YA, Peters MF. An impedance-based cellular assay using human iPSC-derived cardiomyocytes to quantify modulators of cardiac contractility. Toxicol Sci 2014; 142:331-8. [PMID: 25237062 DOI: 10.1093/toxsci/kfu186] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cardiovascular toxicity, a prominent reason for late-stage failures in drug development, has resulted in a demand for in vitro assays that can predict this liability in early drug discovery. Current in vitro cardiovascular safety testing primarily focuses on ion channel modulation and low throughput cardiomyocyte (CM) contractility measurements. We evaluated both human induced pluripotent stem cell-derived CMs (hiPSC-CMs) and rat neonatal CMs (rat CMs) on the xCELLigence Cardio system which uses impedance technology to quantify CM beating properties in a 96-well format. Forty-nine compounds were tested in concentration-response mode to determine potency for modulation of CM beating, a surrogate biomarker for contractility. These compounds had previously been tested in vivo and in a low throughput in vitro optical-based contractility assay that measures sarcomere shortening in electrically paced dog CMs. In comparison with in vivo contractility effects, hiPSC-CM impedance had assay sensitivity, specificity, and accuracy values of 90%, 74%, and 82%, respectively. These values compared favorably to values reported for the dog CM optical assay (83%, 84%, and 82%) and were slightly better than impedance using rat CMs (77%, 74%, and 74%). The potency values from the hiPSC-CM and rat CM assays spanned four orders of magnitude and correlated with values from the dog CM optical assay (r(2 )= 0.76 and 0.70, respectively). The Cardio system assay has >5× higher throughput than the optical assay. Thus, hiPSC-CM impedance testing can help detect the human cardiotoxic potential of novel therapeutics early in drug discovery, and if a hazard is identified, has sufficient throughput to support the design-make-test-analyze cycle to mitigate this liability.
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Affiliation(s)
- Clay W Scott
- *Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, ACEA Biosciences Inc., San Diego, California 92121 and Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Alderley Park, SK10 4TG, UK
| | - Xiaoyu Zhang
- *Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, ACEA Biosciences Inc., San Diego, California 92121 and Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Alderley Park, SK10 4TG, UK
| | - Najah Abi-Gerges
- *Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, ACEA Biosciences Inc., San Diego, California 92121 and Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Alderley Park, SK10 4TG, UK
| | - Sarah D Lamore
- *Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, ACEA Biosciences Inc., San Diego, California 92121 and Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Alderley Park, SK10 4TG, UK
| | - Yama A Abassi
- *Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, ACEA Biosciences Inc., San Diego, California 92121 and Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Alderley Park, SK10 4TG, UK
| | - Matthew F Peters
- *Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, ACEA Biosciences Inc., San Diego, California 92121 and Drug Safety and Metabolism, AstraZeneca Pharmaceuticals, Alderley Park, SK10 4TG, UK
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Lamore SD, Kamendi HW, Scott CW, Dragan YP, Peters MF. Cellular impedance assays for predictive preclinical drug screening of kinase inhibitor cardiovascular toxicity. Toxicol Sci 2013; 135:402-13. [PMID: 23897988 DOI: 10.1093/toxsci/kft167] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular (CV) toxicity is a leading contributor to drug attrition. Implementing earlier testing has successfully reduced human Ether-à-go-go-Related Gene-related arrhythmias. How- ever, analogous assays targeting functional CV effects remain elusive. Demand to address this gap is particularly acute for kinase inhibitors (KIs) that suffer frequent CV toxicity. The drug class also presents some particularly challenging requirements for assessing functional CV toxicity. Specifically, an assay must sense a downstream response that integrates diverse kinase signaling pathways. In addition, sufficient throughput is essential for handling inherent KI nonselectivity. A new opportunity has emerged with cellular impedance technology, which detects spontaneous beating cardiomyocytes. Impedance assays sense morphology changes downstream of cardiomyocyte contraction. To evaluate cardiomyocyte impedance assays for KI screening, we investigated two distinct KI classes where CV toxicity was discovered late and target risks remain unresolved. Microtubule-associated protein/microtubule affinity regulating kinase (MARK) inhibitors decrease blood pressure in dogs, whereas checkpoint kinase (Chk) inhibitors (AZD7762, SCH900776) exhibit dose-limiting CV toxicities in clinical trials. These in vivo effects manifested in vitro as cardiomyocyte beat cessation. MARK effects were deemed mechanism associated because beat inhibition potencies correlated with kinase inhibition, and gene knockdown and microtubule-targeting agents suppressed beating. MARK inhibitor impedance and kinase potencies aligned with rat blood pressure effects. Chk inhibitor effects were judged off-target because Chk and beat inhibition potencies did not correlate and knockdowns did not alter beating. Taken together, the data demonstrate that cardiomyocyte impedance assays can address three unmet needs-detecting KI functional cardiotoxicity in vitro, determining mechanism of action, and supporting safety structure-activity relationships.
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Affiliation(s)
- Sarah D Lamore
- Molecular Toxicology,Global Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, USA
| | - Harriet W Kamendi
- Molecular Toxicology and Safety Pharmacology, Global Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, USA
| | - Clay W Scott
- Molecular Toxicology, Global Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, USA
| | - Yvonne P Dragan
- Molecular Toxicology, Global Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, USA
| | - Matthew F Peters
- Molecular Toxicology, Global Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts 02451, USA
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Peters MF, Scott CW, Ochalski R, Dragan YP. Evaluation of Cellular Impedance Measures of Cardiomyocyte Cultures for Drug Screening Applications. Assay Drug Dev Technol 2012; 10:525-32. [DOI: 10.1089/adt.2011.442] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Matthew F. Peters
- Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts
| | - Clay W Scott
- Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts
| | - Rafal Ochalski
- Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts
| | - Yvonne P. Dragan
- Safety Assessment, AstraZeneca Pharmaceuticals, Waltham, Massachusetts
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Peters MF, Zacco A, Gordon J, Maciag CM, Litwin LC, Thompson C, Schroeder P, Sygowski LA, Piser TM, Brugel TA. Identification of short-acting κ-opioid receptor antagonists with anxiolytic-like activity. Eur J Pharmacol 2011; 661:27-34. [PMID: 21539838 DOI: 10.1016/j.ejphar.2011.04.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 03/16/2011] [Accepted: 04/06/2011] [Indexed: 10/18/2022]
Abstract
The κ-opioid receptor plays a central role in mediating the response to stressful life events. Inhibiting κ-opioid receptor signaling is proposed as a mechanism for treating stress-related conditions such as depression and anxiety. Preclinical testing consistently confirms that disruption of κ-opioid signaling is efficacious in animal models of mood disorders. However, concerns about the feasibility of developing antagonists into drugs stem from an unusual pharmacodynamic property of prototypic κ-opioid receptor-selective antagonists; they inhibit receptor signaling for weeks to months after a single dose. Several fundamental questions include - is it possible to identify short-acting antagonists; is long-lasting inhibition necessary for efficacy; and is it safe to develop long-acting antagonists in the clinic. Here, we test representative compounds (AZ-ECPC, AZ-MTAB, and LY-DMPF) from three new chemical series of κ-opioid receptor ligands for long-lasting inhibition. Each compound dose-dependently reversed κ-opioid agonist-induced diuresis. However, unlike the prototypic antagonist, nBNI, which fully inhibited evoked diuresis for at least four weeks, the new compounds showed no inhibition after one week. The two compounds with greater potency and selectivity were tested in prenatally-stressed rats on the elevated plus maze, an exploration-based model of anxiety. Spontaneous exploration of open arms in the elevated plus maze was suppressed by prenatal stress and restored with both compounds. These findings indicate that persistent inhibition is not an inherent property of κ-opioid-selective antagonists and that post-stress dosing with transient inhibitors can be effective in a mood disorder model. This further supports κ-opioid receptor as a promising target for developing novel psychiatric medications.
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Affiliation(s)
- Matthew F Peters
- AstraZeneca Pharmaceuticals, Wilmington, DE 19850, United States.
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Brugel TA, Smith RW, Balestra M, Becker C, Daniels T, Koether GM, Throner SR, Panko LM, Brown DG, Liu R, Gordon J, Peters MF. SAR development of a series of 8-azabicyclo[3.2.1]octan-3-yloxy-benzamides as kappa opioid receptor antagonists. Part 2. Bioorg Med Chem Lett 2010; 20:5405-10. [DOI: 10.1016/j.bmcl.2010.07.112] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 07/21/2010] [Accepted: 07/26/2010] [Indexed: 11/25/2022]
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Scott CW, Peters MF. Label-free whole-cell assays: expanding the scope of GPCR screening. Drug Discov Today 2010; 15:704-16. [DOI: 10.1016/j.drudis.2010.06.008] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 05/25/2010] [Accepted: 06/16/2010] [Indexed: 11/16/2022]
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Brugel TA, Smith RW, Balestra M, Becker C, Daniels T, Hoerter TN, Koether GM, Throner SR, Panko LM, Folmer JJ, Cacciola J, Hunter AM, Liu R, Edwards PD, Brown DG, Gordon J, Ledonne NC, Pietras M, Schroeder P, Sygowski LA, Hirata LT, Zacco A, Peters MF. Discovery of 8-azabicyclo[3.2.1]octan-3-yloxy-benzamides as selective antagonists of the kappa opioid receptor. Part 1. Bioorg Med Chem Lett 2010; 20:5847-52. [PMID: 20727752 DOI: 10.1016/j.bmcl.2010.07.113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 07/21/2010] [Accepted: 07/26/2010] [Indexed: 11/30/2022]
Abstract
Initial high throughput screening efforts identified highly potent and selective kappa opioid receptor antagonist 3 (κ IC(50)=77 nM; μ:κ and δ:κ IC(50) ratios>400) which lacked CNS exposure in vivo. Modification of this scaffold resulted in development of a series of 8-azabicyclo[3.2.1]octan-3-yloxy-benzamides showing potent and selectivity κ antagonism as well as good brain exposure. Analog 6c (κ IC(50)=20 nM; μ:κ=36, δ:κ=415) was also shown to reverse κ-agonist induced rat diuresis in vivo.
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Affiliation(s)
- Todd A Brugel
- CNS Discovery Research, AstraZeneca Pharmaceuticals, 1800 Concord Pike, Wilmington, DE 19850, USA
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Peters MF, Vaillancourt F, Heroux M, Valiquette M, Scott CW. Comparing Label-Free Biosensors for Pharmacological Screening With Cell-Based Functional Assays. Assay Drug Dev Technol 2010; 8:219-27. [DOI: 10.1089/adt.2009.0232] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Matthew F. Peters
- Lead Generation Department, AstraZeneca Pharmaceuticals LP, Wilmington, Delaware
| | | | - Madeleine Heroux
- In Vitro Biology & DMPK, AstraZeneca, R&D Montreal, Montreal, Quebec, Canada
| | - Manon Valiquette
- In Vitro Biology & DMPK, AstraZeneca, R&D Montreal, Montreal, Quebec, Canada
| | - Clay W. Scott
- Lead Generation Department, AstraZeneca Pharmaceuticals LP, Wilmington, Delaware
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Abstract
G-protein—coupled receptors can couple to different signal transduction pathways in different cell types (termed cell-specific signaling) and can activate different signaling pathways depending on the receptor conformation(s) stabilized by the activating ligand (functional selectivity). These concepts offer potential for developing pathway-specific drugs that increase efficacy and reduce side effects. Despite significant interest, functional selectivity has been difficult to exploit in drug discovery, in part due to the burden of multiple assays. Cellular impedance assays use an emerging technology that can qualitatively distinguish Gs, Gi/o, and Gq signaling in a single assay and is thereby suited for studying these pharmacological concepts. Cellular impedance confirmed cell-specific Gs and Gq coupling for the melanocortin-4 receptor and dual Gi and Gs signaling with the cannabinoid-1 (CB1) receptor. The balance of Gi versus Gs signaling depended on the cell line. In CB1-HEKs, Giand Gs-like responses combined to yield a novel impedance profile demonstrating the dynamic nature of these traces. Cellspecific signaling was observed with endogenous D1 receptor in U-2 cells and SK-N-MC cells, yet the pharmacological profile of partial and full agonists was similar in both cell lines. We conclude that the dynamic impedance profile encodes valuable relative signaling information and is sufficiently robust to help evaluate cell-specific signaling and functional selectivity. ( Journal of Biomolecular Screening 2009:246-255)
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Affiliation(s)
- Matthew F. Peters
- Lead Generation Department, AstraZeneca Pharmaceuticals LP, Wilmington, Delaware,
| | - Clay W. Scott
- Lead Generation Department, AstraZeneca Pharmaceuticals LP, Wilmington, Delaware
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Peters MF, Knappenberger KS, Wilkins D, Sygowski LA, Lazor LA, Liu J, Scott CW. Evaluation of cellular dielectric spectroscopy, a whole-cell, label-free technology for drug discovery on Gi-coupled GPCRs. ACTA ACUST UNITED AC 2007; 12:312-9. [PMID: 17307886 DOI: 10.1177/1087057106298637] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cellular dielectric spectroscopy (CDS) is an emerging technology capable of detecting a range of whole-cell responses in a label-free manner. A new CDS-based instrument, CellKey, has been developed that is optimized for G-protein coupled receptor (GPCR) detection and has automated liquid handling in microplate format, thereby making CDS accessible to lead generation/optimization drug discovery. In addition to having sufficient throughput, new assay technologies must pass rigorous standards for assay development, signal window, dynamic range, and reproducibility to effectively support drug discovery SAR studies. Here, the authors evaluated CellKey with 3 different G(i)-coupled GPCRs for suitability in supporting SAR studies. Optimized assay conditions compatible with the precision, reproducibility, and throughput required for routine screening were quickly achieved for each target. Across a 1000-fold range in compound potencies, CellKey results correlated with agonist and antagonist data obtained using classical methods ([(35)S]GTPgammaS binding and cAMP production). For partial agonists, relative efficacy measurements also correlated with GTPgammaS data. CellKey detection of positive allosteric modulators appeared superior to GTPgammaS methodology. Agonist and antagonist activity could be accurately quantified under conditions of low receptor expression. CellKey is a new technology platform that uses label-free detection in a homogeneous assay that is unaffected by color quenching and is easily integrated into existing microtiter-based compound testing and data analysis procedures for drug discovery.
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Corradi JP, Ravyn V, Robbins AK, Hagan KW, Peters MF, Bostwick R, Buono RJ, Berrettini WH, Furlong ST. Alternative transcripts and evidence of imprinting of GNAL on 18p11.2. Mol Psychiatry 2005; 10:1017-25. [PMID: 16044173 DOI: 10.1038/sj.mp.4001713] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genetic studies implicating the region of human chromosome 18p11.2 in susceptibility to bipolar disorder and schizophrenia have observed parent-of-origin effects that may be explained by genomic imprinting. We have identified a transcriptional variant of the GNAL gene in this region, employing an alternative first exon that is 5' to the originally identified start site. This alternative GNAL transcript encodes a longer functional variant of the stimulatory G-protein alpha subunit, Golf. The isoforms of Golf display different expression patterns in the CNS and functionally couple to the dopamine D1 receptor when heterologously expressed in Sf9 cells. In addition, there are CpG islands in the vicinity of both first exons that are differentially methylated, a hallmark of genomic imprinting. These results suggest that GNAL, and possibly other genes in the region, is subject to epigenetic regulation and strengthen the case for a susceptibility gene in this region.
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Affiliation(s)
- J P Corradi
- Department of Target Biology, AstraZeneca Pharmaceuticals, Wilmington, DE, USA
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17
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Puwarawuttipanit W, Bragg AD, Frydenlund DS, Mylonakou MN, Nagelhus EA, Peters MF, Kotchabhakdi N, Adams ME, Froehner SC, Haug FM, Ottersen OP, Amiry-Moghaddam M. Differential effect of alpha-syntrophin knockout on aquaporin-4 and Kir4.1 expression in retinal macroglial cells in mice. Neuroscience 2005; 137:165-75. [PMID: 16257493 DOI: 10.1016/j.neuroscience.2005.08.051] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Revised: 07/04/2005] [Accepted: 08/07/2005] [Indexed: 11/20/2022]
Abstract
Aquaporin-4 water channels and the inwardly rectifying potassium channels Kir4.1 are coexpressed in a highly polarized manner at the perivascular and subvitreal endfeet of retinal Müller cells and astrocytes. The present study was aimed at resolving the anchoring mechanisms responsible for the coexpression of these molecules. Both aquaporin-4 and Kir4.1 contain PDZ-domain binding motifs at their C-termini and it was recently shown that mice with targeted disruption of the dystrophin gene display altered distribution of aquaporin-4 and Kir4.1 in the retina. To test our hypothesis that alpha-syntrophin (a PDZ-domain containing protein of the dystrophin associated protein complex) is involved in aquaporin-4 and Kir4.1 anchoring in retinal cells, we studied the expression pattern of these molecules in alpha-syntrophin null mice. Judged by quantitative immunogold cytochemistry, deletion of the alpha-syntrophin gene causes a partial loss (by 70%) of aquaporin-4 labeling at astrocyte and Müller cell endfeet but no decrease in Kir4.1 labeling at these sites. These findings suggest that alpha-syntrophin is not involved in the anchoring of Kir4.1 and only partly responsible for the anchoring of aquaporin-4 in retinal endfeet membranes. Furthermore we show that wild type and alpha-syntrophin null mice exhibit strong beta1 syntrophin labeling at perivascular and subvitreal Müller cell endfeet, raising the possibility that beta1 syntrophin might be involved in the anchoring of Kir4.1 and the alpha-syntrophin independent pool of aquaporin-4.
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Affiliation(s)
- W Puwarawuttipanit
- Centre for Molecular Biology and Neuroscience, and Nordic Centre for Water Imbalance Related Disorders, University of Oslo, P.O. Box 1105 Blindern, N-0317 Oslo, Norway
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18
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Jones KJ, Compton AG, Yang N, Mills MA, Peters MF, Mowat D, Kunkel LM, Froehner SC, North KN. Deficiency of the syntrophins and alpha-dystrobrevin in patients with inherited myopathy. Neuromuscul Disord 2003; 13:456-67. [PMID: 12899872 DOI: 10.1016/s0960-8966(03)00066-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The syntrophins and dystrobrevins are members of the dystrophin-associated protein complex, and are thought to function as modular adaptors for signalling proteins recruited to the sarcolemmal membrane. We have characterised the expression of the syntrophins (alpha-, beta1-, and beta2-) and alpha-dystrobrevin by immunohistochemistry in normal human muscle and in biopsies from 162 patients with myopathies of unknown aetiology (with normal staining for dystrophin and other dystrophin-associated proteins). Unlike mice, beta2-syntrophin is expressed at the sarcolemma in post-natal human skeletal muscle. Deficiency of alpha-dystrobrevin +/- beta2-syntrophin was present in 16/162 (10%) patients, compared to age-matched controls. All patients presented with congenital-onset hypotonia and weakness, although there was variability in clinical severity. Two major clinical patterns emerged: patients with deficiency of beta2-syntrophin and alpha-dystrobrevin presented with severe congenital weakness and died in the first year of life, and two patients with deficiency of alpha-dystrobrevin had congenital muscular dystrophy with complete external ophthalmoplegia. We have sequenced the coding regions of alpha-dystrobrevin and beta2-syntrophin in these patients, and identified a new isoform of dystrobrevin, but have not identified any mutations. This suggests that disease causing mutations occur outside the coding region of these genes, in gene(s) encoding other components of the syntrophin-dystrobrevin subcomplex, or in gene(s) responsible for their post-translational modification and normal localisation.
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Affiliation(s)
- K J Jones
- Institute for Neuromuscular Research, The Children's Hospital at Westmead, Locked Bag 4001, NSW 2145, Westmead, Australia
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19
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Igarashi S, Morita H, Bennett KM, Tanaka Y, Engelender S, Peters MF, Cooper JK, Wood JD, Sawa A, Ross CA. Inducible PC12 cell model of Huntington's disease shows toxicity and decreased histone acetylation. Neuroreport 2003; 14:565-8. [PMID: 12657886 DOI: 10.1097/00001756-200303240-00007] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by the abnormal expansion of a polyglutamine tract in the huntingtin protein. We have developed PC12 cell lines in which the expression of an N-terminal truncation of huntingtin (N63) with either wild type (23Q) or expanded polyglutamine (148Q) can be induced by the removal of doxycycline. Differentiated PC12 cells induced to express N63-148Q showed cellular toxicity reaching up to 50% at 6 days post-induction. Histone acetyltransferase (HAT) activity and global histone acetylation was significantly decreased in cells expressing truncated huntingtin with mutant but not normal huntingtin. These data suggest that altered chromatin modification via reduction in coactivator activity may cause neuronal transcriptional dysregulation and contribute to cellular toxicity.
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Affiliation(s)
- Shuichi Igarashi
- Department of Neuroscience, Brain Research Institute, Niigata University, I Asahimachi, Niigata 951-8585, Japan
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20
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Nucifora FC, Sasaki M, Peters MF, Huang H, Cooper JK, Yamada M, Takahashi H, Tsuji S, Troncoso J, Dawson VL, Dawson TM, Ross CA. Interference by huntingtin and atrophin-1 with cbp-mediated transcription leading to cellular toxicity. Science 2001; 291:2423-8. [PMID: 11264541 DOI: 10.1126/science.1056784] [Citation(s) in RCA: 775] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Expanded polyglutamine repeats have been proposed to cause neuronal degeneration in Huntington's disease (HD) and related disorders, through abnormal interactions with other proteins containing short polyglutamine tracts such as the transcriptional coactivator CREB binding protein, CBP. We found that CBP was depleted from its normal nuclear location and was present in polyglutamine aggregates in HD cell culture models, HD transgenic mice, and human HD postmortem brain. Expanded polyglutamine repeats specifically interfere with CBP-activated gene transcription, and overexpression of CBP rescued polyglutamine-induced neuronal toxicity. Thus, polyglutamine-mediated interference with CBP-regulated gene transcription may constitute a genetic gain of function, underlying the pathogenesis of polyglutamine disorders.
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Affiliation(s)
- F C Nucifora
- Division of Neurobiology, Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196, USA
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21
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Abstract
Huntington's disease is caused by an expanded CAG trinucleotide repeat coding for a polyglutamine stretch within the huntingtin protein. Currently, the function of normal huntingtin and the mechanism by which expanded huntingtin causes selective neurotoxicity remain unknown. Clues may come from the identification of huntingtin-associated proteins (HAPs). Here, we show that huntingtin copurifies with a single novel 40-kDa protein termed HAP40. HAP40 is encoded by the open reading frame factor VIII-associated gene A (F8A) located within intron 22 of the factor VIII gene. In transfected cell extracts, HAP40 coimmunoprecipitates with full-length huntingtin but not with an N-terminal huntingtin fragment. Recombinant HAP40 is cytoplasmic in the presence of huntingtin but is actively targeted to the nucleus in the absence of huntingtin. These data indicate that HAP40 is likely to contribute to the function of normal huntingtin and is a candidate for involvement in the aberrant nuclear localization of mutant huntingtin found in degenerating neurons in Huntington's disease.
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Affiliation(s)
- M F Peters
- Division of Neurobiology, Department of Psychiatry, Department of Neuroscience, and The Program in Cellular and Molecular Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA.
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22
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Rocco P, Vainzof M, Froehner SC, Peters MF, Marie SK, Passos-Bueno MR, Zatz M. Brazilian family with pure autosomal dominant spastic paraplegia maps to 8q: analysis of muscle beta 1 syntrophin. Am J Med Genet 2000; 92:122-7. [PMID: 10797436 DOI: 10.1002/(sici)1096-8628(20000515)92:2<122::aid-ajmg8>3.0.co;2-b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The autosomal dominant hereditary spastic paraplegias (AD-HSP) are a heterogeneous group of degenerative disorders of the central motor system, characterized by progressive spasticity of the lower limbs. Five loci for pure AD-HSP have been identified to date: SPG3 at 14q, SPG4 at 2p, SPG6 at 15q, SPG8 at 8q, and more recently SPG10 at 12q. We have analyzed a Brazilian family with 16 affected individuals by pure AD-HSP who developed progressive gait disturbance with onset at age 18-26 years. Linkage analysis performed with 13 relatives (6 affected and 7 normal) excluded SPG3, SPG4, and SPG6 as candidate regions. However, positive LOD scores were obtained with markers flanking the candidate region for the SPG8 locus [maximum two point Lod score (Zmax) = 3.3 at theta = 0 for D8S1804]. In this region lies the syntrophin beta 1 gene (SNT2B1), a widely expressed dystrophin-associated protein and therefore a good positional and functional candidate for this disease. Immunohistochemical and Western Blot (WB) studies showed that the distribution, expression, and apparent molecular weight of the beta 1 syntrophin protein were comparable to those of normal control individuals. Therefore, it is unlikely that defects in this protein are related to SPG8, at least in the present family.
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Affiliation(s)
- P Rocco
- Centro de Estudos do Genoma Humano, Department of Biology, University of Sao Paulo, São Paulo, Brazil
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23
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Abstract
At least eight neurodegenerative diseases result from expansions of polyglutamine tracts encoded by CAG trinucleotide repeats. Although polyglutamine diseases typically have onset after age 50 in humans, these diseases can be modeled in animals and in cell culture by using highly expanded repeats to accelerate the pathogenesis. Unfortunately, current methods for preparing recombinant constructs with large glutamine tracts either alter the coding region adjacent to the repeat or yield highly unstable pure CAG repeats. We have developed a technique for expanding repeats that results in a more stable mix of CAG and CAA glutamine codons. We expect this technique to allow rapid preparation of highly expand repeats suitable for stable animal and cell culture models for any of the polyglutamine repeat diseases.
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Affiliation(s)
- M F Peters
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196, USA
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24
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Peters MF, Nucifora FC, Kushi J, Seaman HC, Cooper JK, Herring WJ, Dawson VL, Dawson TM, Ross CA. Nuclear targeting of mutant Huntingtin increases toxicity. Mol Cell Neurosci 1999; 14:121-8. [PMID: 10479410 DOI: 10.1006/mcne.1999.0773] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Huntington's disease is a neurodegenerative disorder resulting from expansion of the polyglutamine region in huntingtin. Although huntingtin is normally cytoplasmic, in affected brain regions proteolytic fragments of mutant huntingtin containing the polyglutamine repeat form intranuclear inclusions. Here, we examine the contribution of nuclear localization to toxicity by transiently transfecting neuro-2a cells with an N-terminal huntingtin fragment similar in size to that believed to be present in patients. The huntingtin fragment, HD-N63, was targeted either to the cytoplasm with a nuclear export signal (NES) or to the nucleus with a nuclear localization signal (NLS). The NES decreased the number of cells with aggregates in the nucleus while an NLS had the opposite effect. By cotransfecting HD-N63 with GFP as a marker, we observed direct cell loss with constructs containing expanded polyglutamine repeats. Compared to unmodified HD-N63-75Q, adding an NES reduced cell loss by 57% while an NLS increased cell loss by 111%. These results indicate that nuclear localization of mutant huntingtin fragments plays an important role in cell toxicity.
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Affiliation(s)
- M F Peters
- Division of Neurobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205-2196, USA
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25
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Ross CA, Wood JD, Schilling G, Peters MF, Nucifora FC, Cooper JK, Sharp AH, Margolis RL, Borchelt DR. Polyglutamine pathogenesis. Philos Trans R Soc Lond B Biol Sci 1999; 354:1005-11. [PMID: 10434299 PMCID: PMC1692617 DOI: 10.1098/rstb.1999.0452] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An increasing number of neurodegenerative disorders have been found to be caused by expanding CAG triplet repeats that code for polyglutamine. Huntington's disease (HD) is the most common of these disorders and dentatorubral-pallidoluysian atrophy (DRPLA) is very similar to HD, but is caused by mutation in a different gene, making them good models to study. In this review, we will concentrate on the roles of protein aggregation, nuclear localization and proteolytic processing in disease pathogenesis. In cell model studies of HD, we have found that truncated N-terminal portions of huntingtin (the HD gene product) with expanded repeats form more aggregates than longer or full length huntingtin polypeptides. These shorter fragments are also more prone to aggregate in the nucleus and cause more cell toxicity. Further experiments with huntingtin constructs harbouring exogenous nuclear import and nuclear export signals have implicated the nucleus in direct cell toxicity. We have made mouse models of HD and DRPLA using an N-terminal truncation of huntingtin (N171) and full-length atrophin-1 (the DRPLA gene product), respectively. In both models, diffuse neuronal nuclear staining and nuclear inclusion bodies are observed in animals expressing the expanded glutamine repeat protein, further implicating the nucleus as a primary site of neuronal dysfunction. Neuritic pathology is also observed in the HD mice. In the DRPLA mouse model, we have found that truncated fragments of atrophin-1 containing the glutamine repeat accumulate in the nucleus, suggesting that proteolysis may be critical for disease progression. Taken together, these data lead towards a model whereby proteolytic processing, nuclear localization and protein aggregation all contribute to pathogenesis.
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Affiliation(s)
- C A Ross
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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26
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Peters MF, Sadoulet-Puccio HM, Grady MR, Kramarcy NR, Kunkel LM, Sanes JR, Sealock R, Froehner SC. Differential membrane localization and intermolecular associations of alpha-dystrobrevin isoforms in skeletal muscle. J Cell Biol 1998; 142:1269-78. [PMID: 9732287 PMCID: PMC2149339 DOI: 10.1083/jcb.142.5.1269] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [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: 05/18/1998] [Revised: 07/08/1998] [Indexed: 11/22/2022] Open
Abstract
alpha-Dystrobrevin is both a dystrophin homologue and a component of the dystrophin protein complex. Alternative splicing yields five forms, of which two predominate in skeletal muscle: full-length alpha-dystrobrevin-1 (84 kD), and COOH-terminal truncated alpha-dystrobrevin-2 (65 kD). Using isoform-specific antibodies, we find that alpha-dystrobrevin-2 is localized on the sarcolemma and at the neuromuscular synapse, where, like dystrophin, it is most concentrated in the depths of the postjunctional folds. alpha-Dystrobrevin-2 preferentially copurifies with dystrophin from muscle extracts. In contrast, alpha-dystrobrevin-1 is more highly restricted to the synapse, like the dystrophin homologue utrophin, and preferentially copurifies with utrophin. In yeast two-hybrid experiments and coimmunoprecipitation of in vitro-translated proteins, alpha-dystrobrevin-2 binds dystrophin, whereas alpha-dystrobrevin-1 binds both dystrophin and utrophin. alpha-Dystrobrevin-2 was lost from the nonsynaptic sarcolemma of dystrophin-deficient mdx mice, but was retained on the perisynaptic sarcolemma even in mice lacking both utrophin and dystrophin. In contrast, alpha-dystrobrevin-1 remained synaptically localized in mdx and utrophin-negative muscle, but was absent in double mutants. Thus, the distinct distributions of alpha-dystrobrevin-1 and -2 can be partly explained by specific associations with utrophin and dystrophin, but other factors are also involved. These results show that alternative splicing confers distinct properties of association on the alpha-dystrobrevins.
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Affiliation(s)
- M F Peters
- Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7545, USA
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27
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Cooper JK, Schilling G, Peters MF, Herring WJ, Sharp AH, Kaminsky Z, Masone J, Khan FA, Delanoy M, Borchelt DR, Dawson VL, Dawson TM, Ross CA. Truncated N-terminal fragments of huntingtin with expanded glutamine repeats form nuclear and cytoplasmic aggregates in cell culture. Hum Mol Genet 1998; 7:783-90. [PMID: 9536081 DOI: 10.1093/hmg/7.5.783] [Citation(s) in RCA: 258] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Huntington's disease (HD) is a progressive neurodegenerative disorder caused by an expanding CAG repeat coding for polyglutamine in the huntingtin protein. Recent data have suggested the possibility that an N-terminal fragment of huntingtin may aggregate in neurons of patients with HD, both in the cytoplasm, forming dystrophic neurites, and in the nucleus, forming intranuclear neuronal inclusion bodies. An animal model of HD using the short N-terminal fragment of huntingtin has also been found to have intranuclear inclusions and this same fragment can aggregate in vitro . We have now developed a cell culture model demonstrating that N-terminal fragments of huntingtin with expanded glutamine repeats aggregate both in the cytoplasm and in the nucleus. Neuroblastoma cells transiently transfected with full-length huntingtin constructs with either a normal or expanded repeat had diffuse cytoplasmic localization of the protein. In contrast, cells transfected with truncated N-terminal fragments showed aggregation only if the glutamine repeat was expanded. The aggregates were often ubiquitinated. The shorter truncated product appeared to form more aggregates in the nucleus. Cells transfected with the expanded repeat construct but not the normal repeat construct showed enhanced toxicity to the apoptosis-inducing agent staurosporine. These data indicate that N-terminal truncated fragments of huntingtin with expanded glutamine repeats can aggregate in cells in culture and that this aggregation can be toxic to cells. This model will be useful for future experiments to test mechanisms of aggregation and toxicity and potentially for testing experimental therapeutic interventions.
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Affiliation(s)
- J K Cooper
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196, USA
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28
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Peters MF, O'Brien KF, Sadoulet-Puccio HM, Kunkel LM, Adams ME, Froehner SC. beta-dystrobrevin, a new member of the dystrophin family. Identification, cloning, and protein associations. J Biol Chem 1997; 272:31561-9. [PMID: 9395493 DOI: 10.1074/jbc.272.50.31561] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Dystrophin, the protein disrupted in Duchenne muscular dystrophy, is one of several related proteins that are key components of the submembrane cytoskeleton. Three dystrophin-related proteins (utrophin, dystrophin-related protein-2 (DRP2), and dystrobrevin) have been described. Here, we identify a human gene on chromosome 2p22-23 that encodes a novel protein, beta-dystrobrevin, with significant homology to the other known dystrobrevin (now termed alpha-dystrobrevin). Sequence alignments including this second dystrobrevin strongly support the concept that two distinct subfamilies exist within the dystrophin family, one composed of dystrophin, utrophin, and DRP2 and the other composed of alpha- and beta-dystrobrevin. The possibility that members of each subfamily form distinct protein complexes was examined by immunopurifying dystrobrevins and dystrophin. A beta-dystrobrevin antibody recognized a protein of the predicted size (71 kDa) that copurified with the dystrophin short form, Dp71. Thus, like alpha-dystrobrevin, beta-dystrobrevin is likely to associate directly with dystrophin. alpha- and beta-dystrobrevins failed to copurify with each other, however. These results suggest that members of the dystrobrevin subfamily form heterotypic associations with dystrophin and raise the possibility that pairing of a particular dystrobrevin with dystrophin may be regulated, thereby providing a mechanism for assembly of distinct submembrane protein complexes.
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Affiliation(s)
- M F Peters
- Department of Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7545, USA
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29
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Abstract
The syntrophins are a multigene family of intracellular dystrophin-associated proteins comprising three isoforms, alpha1, beta1, and beta2. Based on their domain organization and association with neuronal nitric oxide synthase, syntrophins are thought to function as modular adapters that recruit signaling proteins to the membrane via association with the dystrophin complex. Using sequences derived from a new mouse beta1-syntrophin cDNA, and previously isolated cDNAs for alpha1- and beta2-syntrophins, we prepared isoform-specific antibodies to study the expression, skeletal muscle localization, and dystrophin family association of all three syntrophins. Most tissues express multiple syntrophin isoforms. In mouse gastrocnemius skeletal muscle, alpha1- and beta1-syntrophin are concentrated at the neuromuscular junction but are also present on the extrasynaptic sarcolemma. beta1-syntrophin is restricted to fast-twitch muscle fibers, the first fibers to degenerate in Duchenne muscular dystrophy. beta2-syntrophin is largely restricted to the neuromuscular junction. The sarcolemmal distribution of alpha1- and beta1-syntrophins suggests association with dystrophin and dystrobrevin, whereas all three syntrophins could potentially associate with utrophin at the neuromuscular junction. Utrophin complexes immunoisolated from skeletal muscle are highly enriched in beta1- and beta2-syntrophins, while dystrophin complexes contain mostly alpha1- and beta1-syntrophins. Dystrobrevin complexes contain dystrophin and alpha1- and beta1-syntrophins. From these results, we propose a model in which a dystrophin-dystrobrevin complex is associated with two syntrophins. Since individual syntrophins do not have intrinsic binding specificity for dystrophin, dystrobrevin, or utrophin, the observed preferential pairing of syntrophins must depend on extrinsic regulatory mechanisms.
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Affiliation(s)
- M F Peters
- Department of Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7545, USA
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30
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Abstract
Guanylin, a peptide purified from rat jejunum, is thought to regulate water and electrolyte balance in the intestine. We show here, using a combination of Northern blots, Western blots, and functional assays, that guanylin and its receptor (GCC) are not distributed in parallel within the rat intestine. To investigate the possibility that there might be a second intestinal peptide that serves as a ligand for GCC, we assayed tissue extracts for the ability to stimulate cyclic GMP synthesis in a GCC-expression cell line. Duodenal extracts display a peak of biological activity that is not present in colon and that does not comigrate with guanylin or proguanylin. The activity co-purifies with a novel peptide (TIATDECELCINVACTGC) that has high homology with uroguanylin, a peptide initially purified from human and opossum urine. A rat uroguanylin cDNA clone was found to encode a propeptide whose C-terminus corresponds to our purified peptide. Northern blots with probes generated from this clone reveal that prouroguanylin mRNA is strongly expressed in proximal small intestine, but virtually absent from colon, corroborating our biochemical measurements. Taken together, these studies demonstrate an intestinal origin for uroguanylin, and show that within the intestine its distribution is complementary to that of guanylin.
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Affiliation(s)
- Z Li
- Department of Physiology, University of North Carolina, Chapel Hill 27599, USA.
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Froehner SC, Adams ME, Peters MF, Gee SH. Syntrophins: modular adapter proteins at the neuromuscular junction and the sarcolemma. Soc Gen Physiol Ser 1997; 52:197-207. [PMID: 9210230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- S C Froehner
- Department of Physiology, University of North Carolina, Chapel Hill 27599-7545, USA
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Chao DS, Gorospe JR, Brenman JE, Rafael JA, Peters MF, Froehner SC, Hoffman EP, Chamberlain JS, Bredt DS. Selective loss of sarcolemmal nitric oxide synthase in Becker muscular dystrophy. J Exp Med 1996; 184:609-18. [PMID: 8760814 PMCID: PMC2192729 DOI: 10.1084/jem.184.2.609] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Becker muscular dystrophy is an X-linked disease due to mutations of the dystrophin gene. We now show that neuronal-type nitric oxide synthase (nNOS), an identified enzyme in the dystrophin complex, is uniquely absent from skeletal muscle plasma membrane in many human Becker patients and in mouse models of dystrophinopathy. An NH2-terminal domain of nNOS directly interacts with alpha 1-syntrophin but not with other proteins in the dystrophin complex analyzed. However, nNOS does not associate with alpha 1-syntrophin on the sarcolemma in transgenic mdx mice expressing truncated dystrophin proteins. This suggests a ternary interaction of nNOS, alpha 1-syntrophin, and the central domain of dystrophin in vivo, a conclusion supported by developmental studies in muscle. These data indicate that proper assembly of the dystrophin complex is dependent upon the structure of the central rodlike domain and have implications for the design of dystrophin-containing vectors for gene therapy.
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Affiliation(s)
- D S Chao
- Department of Physiology, University of California at San Francisco School of Medicine 94143-0444, USA
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Abstract
Dystrophin-related and -associated proteins are important in the formation and maintenance of the mammalian neuromuscular junction. We have characterized mouse cDNA clones encoding isoforms of the dystrophin-homologous 87-kDa postsynaptic protein, dystrobrevin. In Torpedo, the 87-kDa protein is multiply phosphorylated and closely associated with proteins in the postsynaptic cytoskeleton, including the acetylcholine receptor. In contrast to Torpedo, where only a single transcript is seen, the mouse expresses several mRNAs encoding different isoforms. A 6.0-kilobase transcript in brain encodes a 78-kDa protein (dystrobrevin-2) that has a different C terminus, lacking the putative tyrosine kinase substrate domain. In skeletal and cardiac muscle, transcripts of 1.7 and 3.3/3.5 kilobases predominate and encode additional isoforms. Alternative splicing within the coding region and differential usage of untranslated regions produce additional variation. Multiple dystrobrevin-immunoreactive proteins copurify with syntrophin from mouse tissues. In skeletal muscle, dystrobrevin immunoreactivity is restricted to the neuromuscular junction and sarcolemma. The occurrence of many dystrobrevin isoforms is significant because alternative splicing and phosphorylation often have profound effects upon the biological activity of synaptic proteins.
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Affiliation(s)
- D J Blake
- Molecular Genetics Group, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
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Brenman JE, Chao DS, Gee SH, McGee AW, Craven SE, Santillano DR, Wu Z, Huang F, Xia H, Peters MF, Froehner SC, Bredt DS. Interaction of nitric oxide synthase with the postsynaptic density protein PSD-95 and alpha1-syntrophin mediated by PDZ domains. Cell 1996; 84:757-67. [PMID: 8625413 DOI: 10.1016/s0092-8674(00)81053-3] [Citation(s) in RCA: 1259] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neuronal nitric oxide synthase (nNOS) is concentrated at synaptic junctions in brain and motor endplates in skeletal muscle. Here, we show that the N-terminus of nNOS, which contains a PDZ protein motif, interacts with similar motifs in postsynaptic density-95 protein (PSD-95) and a related novel protein, PSD-93.nNOS and PSD-95 are coexpressed in numerous neuronal populations, and a PSD-95/nNOS complex occurs in cerebellum. PDZ domain interactions also mediate binding of nNOS to skeletal muscle syntrophin, a dystrophin-associated protein. nNOS isoforms lacking a PDZ domain, identified in nNOSdelta/delta mutant mice, do not associate with PSD-95 in brain or with skeletal muscle sarcolemma. Interaction of PDZ-containing domains therefore mediates synaptic association of nNOS and may play a more general role in formation of macromolecular signaling complexes.
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Affiliation(s)
- J E Brenman
- Department of Physiology, School of Medicine, University of California at San Fancisco, California 94143, USA
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Peters MF, Kramarcy NR, Sealock R, Froehner SC. beta 2-Syntrophin: localization at the neuromuscular junction in skeletal muscle. Neuroreport 1994; 5:1577-80. [PMID: 7819523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The syntrophins are a multigene family of proteins which bind C-terminal domains of dystrophin, utrophin and homologs thereof. We report here that antibodies specific for one isoform, beta 2-syntrophin, labeled only the neuromuscular junction (NMJ) in rat skeletal muscle. Anti-alpha 1-syntrophin antibodies gave strong labeling of the sarcolemma and NMJ in normal rat and mouse muscle, and similar but much weaker labeling in dystrophin-minus mdx muscle. beta 2-Syntrophin therefore appears to be specific to the NMJ in normal muscle, as is utrophin, and may be involved in acetylcholine receptor clustering. alpha 1-Syntrophin appears to be associated mainly with dystrophin, as expected, but a small portion must be associated with another protein, possibly homologs of the electric tissue 87K protein.
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Affiliation(s)
- M F Peters
- Department of Physiology, University of North Carolina, Chapel Hill 27599-7545
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Adams ME, Butler MH, Dwyer TM, Peters MF, Murnane AA, Froehner SC. Two forms of mouse syntrophin, a 58 kd dystrophin-associated protein, differ in primary structure and tissue distribution. Neuron 1993; 11:531-40. [PMID: 7691103 DOI: 10.1016/0896-6273(93)90157-m] [Citation(s) in RCA: 177] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Syntrophin, a 58 kd extrinsic membrane protein, is concentrated at postsynaptic sites at the neuromuscular junction and may be involved in clustering acetylcholine receptors. In muscle and nonmuscle tissues, syntrophin is associated with dystrophin, utrophin, and two homologs of the dystrophin carboxy-terminal region. We have isolated three cDNAs encoding Torpedo and mouse syntrophins. The Torpedo cDNA encodes a full-length protein, and on Northern blots recognizes a 3.5 kb mRNA. The two mouse syntrophin cDNAs are products of separate genes but encode proteins that share 50% identity. Syntrophin-1 mRNA (2.2 kb) is expressed at highest levels in skeletal muscle. Syntrophin-2 mRNAs (2.2, 5.0, and 10 kb) are expressed in all mouse tissues examined. These patterns of expression suggest that syntrophin-1 and syntrophin-2 may associate with different members of the dystrophin family.
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Affiliation(s)
- M E Adams
- Department of Physiology, University of North Carolina, Chapel Hill 27599
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Collier AC, Peters MF, Cohn MU. Schedule-induced drinking by rats in the runway on DNC schedules of reinforcement. Physiol Behav 1981; 27:1015-8. [PMID: 7335802 DOI: 10.1016/0031-9384(81)90363-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Wagemaker G, Peters MF, Bol SJ. Induction of erythropoietin responsiveness in vitro by a distinct population of bone marrow cells. Cell Tissue Kinet 1979; 12:521-37. [PMID: 316359 DOI: 10.1111/j.1365-2184.1979.tb00174.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bone marrow contains a small population of primitive erythroid progenitor cells which can be detected by their capacity to form large numbers of erythroid progeny in viscous cultures containing erythropoietin (EP). These cells have been termed erythroid 'burst-forming units' (BFUe). The present study demonstrates that expression of the erythroid differentiation potential of BFUe requires the presence of an activity additional to EP. This activity has been designated as BFA (burst feeder activity). It is shown that the number of BFUe detected and their apparent sensitivity to EP are directly related to the BFA concentration of the cultures. BFA was found to be associated with a population of bone marrow cells of high buoyant density and small volume, which are sensitive to irradiation. The radiation dose-effect curve provided strong evidence that bone marrow BFA is independent of cell proliferation; this was supported by showing that BFA is unaffected by in vivo treatment with hydroxyurea. The findings are compatible with a two-step regulation model for erythroid differentiation in which BFA-induced progeny of BFUe acquire sensitivity to EP.
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Wagemaker G, Peters MF. Effects of human leukocyte conditioned medium on mouse haemopoietic progenitor cells. Cell Tissue Kinet 1978; 11:45-56. [PMID: 304764 DOI: 10.1111/j.1365-2184.1978.tb00874.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Medium conditioned by human peripheral blood leukocytes (HLCM) was studied for its in vitro effects on haemopoietic progenitor cells (CFU-s and CFU-c) present in mouse bone marrow. HLCM has poor colony stimulating activity in semi-solid cultures of mouse bone marrow cells, but invariably increases the number of colonies obtained in the presence of plateau levels of semi-purified colony stimulating factor (CSF). In liquid cultures, HLCM appears to contain a potent initiator of DNA synthesis in CFU-s, an activity which coincides with an increased CFU-s maintenance and causes a three- to four-fold increase in CFU-c number. It is apparent from this study that HLCM, in addition to stimulating colony formation in cultures of human bone marrow cells, has a profound in vitro effect on primitive haemopoietic progenitor cells of the mouse, which cannot be attributed to CSF.
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