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Lawlor MW, Schoser B, Margeta M, Sewry CA, Jones KA, Shieh PB, Kuntz NL, Smith BK, Dowling JJ, Müller-Felber W, Bönnemann CG, Seferian AM, Blaschek A, Neuhaus S, Foley AR, Saade DN, Tsuchiya E, Qasim UR, Beatka M, Prom MJ, Ott E, Danielson S, Krakau P, Kumar SN, Meng H, Vanden Avond M, Wells C, Gordish-Dressman H, Beggs AH, Christensen S, Conner E, James ES, Lee J, Sadhu C, Miller W, Sepulveda B, Varfaj F, Prasad S, Rico S. Effects of gene replacement therapy with resamirigene bilparvovec (AT132) on skeletal muscle pathology in X-linked myotubular myopathy: results from a substudy of the ASPIRO open-label clinical trial. EBioMedicine 2024; 99:104894. [PMID: 38086156 PMCID: PMC10758703 DOI: 10.1016/j.ebiom.2023.104894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 10/27/2023] [Accepted: 11/14/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND X-linked myotubular myopathy (XLMTM) is a rare, life-threatening congenital muscle disease caused by mutations in the MTM1 gene that result in profound muscle weakness, significant respiratory insufficiency, and high infant mortality. There is no approved disease-modifying therapy for XLMTM. Resamirigene bilparvovec (AT132; rAAV8-Des-hMTM1) is an investigational adeno-associated virus (AAV8)-mediated gene replacement therapy designed to deliver MTM1 to skeletal muscle cells and achieve long-term correction of XLMTM-related muscle pathology. The clinical trial ASPIRO (NCT03199469) investigating resamirigene bilparvovec in XLMTM is currently paused while the risk:benefit balance associated with this gene therapy is further investigated. METHODS Muscle biopsies were taken before treatment and 24 and 48 weeks after treatment from ten boys with XLMTM in a clinical trial of resamirigene bilparvovec (ASPIRO; NCT03199469). Comprehensive histopathological analysis was performed. FINDINGS Baseline biopsies uniformly showed findings characteristic of XLMTM, including small myofibres, increased internal or central nucleation, and central aggregates of organelles. Biopsies taken at 24 weeks post-treatment showed marked improvement of organelle localisation, without apparent increases in myofibre size in most participants. Biopsies taken at 48 weeks, however, did show statistically significant increases in myofibre size in all nine biopsies evaluated at this timepoint. Histopathological endpoints that did not demonstrate statistically significant changes with treatment included the degree of internal/central nucleation, numbers of triad structures, fibre type distributions, and numbers of satellite cells. Limited (predominantly mild) treatment-associated inflammatory changes were seen in biopsy specimens from five participants. INTERPRETATION Muscle biopsies from individuals with XLMTM treated with resamirigene bilparvovec display statistically significant improvement in organelle localisation and myofibre size during a period of substantial improvements in muscle strength and respiratory function. This study identifies valuable histological endpoints for tracking treatment-related gains with resamirigene bilparvovec, as well as endpoints that did not show strong correlation with clinical improvement in this human study. FUNDING Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.).
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Affiliation(s)
- Michael W Lawlor
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA.
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Department of Neurology, Ludwig Maximilian University of Munich, 80336, Germany
| | - Marta Margeta
- Department of Pathology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Caroline A Sewry
- Wolfson Centre of Inherited Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital for Children, 30 Guilford Street, London, WC1N 1EH, UK
| | - Karra A Jones
- Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Perry B Shieh
- Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, CA, 90095, USA
| | - Nancy L Kuntz
- Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, IL, 60611, USA
| | - Barbara K Smith
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32610-0154, USA
| | | | - Wolfgang Müller-Felber
- Dr. von Hauner Children's Hospital, Klinikum der Universität München, 80337, Munich, Germany
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, NIH, Bethesda, MD, 20892-1477, USA
| | | | - Astrid Blaschek
- Dr. von Hauner Children's Hospital, Klinikum der Universität München, 80337, Munich, Germany
| | - Sarah Neuhaus
- Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, NIH, Bethesda, MD, 20892-1477, USA
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, NIH, Bethesda, MD, 20892-1477, USA
| | - Dimah N Saade
- Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, NIH, Bethesda, MD, 20892-1477, USA
| | | | - Ummulwara R Qasim
- Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, CA, 90095, USA
| | - Margaret Beatka
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA
| | - Mariah J Prom
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA
| | - Emily Ott
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA
| | - Susan Danielson
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA
| | - Paul Krakau
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA
| | - Suresh N Kumar
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA
| | - Hui Meng
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA
| | - Mark Vanden Avond
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA
| | - Clive Wells
- Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA
| | - Heather Gordish-Dressman
- Children's National Hospital and George Washington University School of Medicine and Health Sciences Department of Pediatrics, Washington, DC, 20037, USA
| | - Alan H Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Sarah Christensen
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Edward Conner
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Emma S James
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Jun Lee
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Chanchal Sadhu
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Weston Miller
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Bryan Sepulveda
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Fatbardha Varfaj
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Suyash Prasad
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
| | - Salvador Rico
- Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA
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Sadhu C, Lyons C, Oh J, Jagadeeswaran I, Gray SJ, Sinnett SE. The Efficacy of a Human-Ready mini MECP2 Gene Therapy in a Pre-Clinical Model of Rett Syndrome. Genes (Basel) 2023; 15:31. [PMID: 38254921 PMCID: PMC10815157 DOI: 10.3390/genes15010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
Inactivating mutations and the duplication of methyl-CpG binding protein 2 (MeCP2), respectively, mediate Rett syndrome (RTT) and MECP2 duplication syndrome. These disorders underscore the conceptual dose-dependent risk posed by MECP2 gene therapy for mosaic RTT patients. Recently, a miRNA-Responsive Autoregulatory Element (miRARE) mitigated the dose-dependent toxicity posed by self-complementary adeno-associated viral vector serotype 9 (AAV9) miniMECP2 gene therapy (scAAV9/miniMECP2-myc) in mice. Here, we report an efficacy assessment for the human-ready version of this regulated gene therapy (TSHA-102) in male Mecp2-/y knockout (KO) mice after intracerebroventricular (ICV) administration at postnatal day 2 (P2) and after intrathecal (IT) administration at P7, P14 (±immunosuppression), and P28 (±immunosuppression). We also report qPCR studies on KO mice treated at P7-P35; protein analyses in KO mice treated at P38; and a survival safety study in female adult Mecp2-/+ mice. In KO mice, TSHA-102 improved respiration, weight, and survival across multiple doses and treatment ages. TSHA-102 significantly improved the front average stance and swing times relative to the front average stride time after P14 administration of the highest dose for that treatment age. Viral genomic DNA and miniMECP2 mRNA were present in the CNS. MiniMeCP2 protein expression was higher in the KO spinal cord compared to the brain. In female mice, TSHA-102 permitted survivals that were similar to those of vehicle-treated controls. In all, these pivotal data helped to support the regulatory approval to initiate a clinical trial for TSHA-102 in RTT patients (clinical trial identifier number NCT05606614).
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Affiliation(s)
- Chanchal Sadhu
- Formerly of Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Christopher Lyons
- Formerly of the Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Jiyoung Oh
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Indumathy Jagadeeswaran
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Steven J. Gray
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Sarah E. Sinnett
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
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Wong H, Hooper AW, Kang HR, Lee SJ, Zhao J, Sadhu C, Rawat S, Gray SJ, Hampson DR. CNS-dominant human FMRP isoform rescues seizures, fear, and sleep abnormalities in Fmr1-KO mice. JCI Insight 2023; 8:169650. [PMID: 37288657 PMCID: PMC10393223 DOI: 10.1172/jci.insight.169650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/18/2023] [Indexed: 06/09/2023] Open
Abstract
Fragile X syndrome is a neurodevelopmental disorder caused by the absence of the mRNA-binding protein fragile X messenger ribonucleoprotein (FMRP). Because FMRP is a highly pleiotropic protein controlling the expression of hundreds of genes, viral vector-mediated gene replacement therapy is viewed as a potential viable treatment to correct the fundamental underlying molecular pathology inherent in the disorder. Here, we studied the safety profile and therapeutic effects of a clinically relevant dose of a self-complementary adeno-associated viral (AAV) vector containing a major human brain isoform of FMRP after intrathecal injection into wild-type and fragile X-KO mice. Analysis of the cellular transduction in the brain indicated primarily neuronal transduction with relatively sparse glial expression, similar to endogenous FMRP expression in untreated wild-type mice. AAV vector-treated KO mice showed recovery from epileptic seizures, normalization of fear conditioning, reversal of slow-wave deficits as measured via electroencephalographic recordings, and restoration of abnormal circadian motor activity and sleep. Further assessment of vector efficacy by tracking and analyzing individual responses demonstrated correlations between the level and distribution of brain transduction and drug response. These preclinical findings further demonstrate the validity of AAV vector-mediated gene therapy for treating the most common genetic cause of cognitive impairment and autism in children.
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Affiliation(s)
- Hayes Wong
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Alexander Wm Hooper
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Hye Ri Kang
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Shiron J Lee
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Jiayi Zhao
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Steven J Gray
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - David R Hampson
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
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Chen X, Lim DA, Lawlor MW, Dimmock D, Vite CH, Lester T, Tavakkoli F, Sadhu C, Prasad S, Gray SJ. Biodistribution of Adeno-Associated Virus Gene Therapy Following Cerebrospinal Fluid-Directed Administration. Hum Gene Ther 2023; 34:94-111. [PMID: 36606687 DOI: 10.1089/hum.2022.163] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Adeno-associated virus (AAV)-based gene therapies, exemplified by the approved therapy for spinal muscular atrophy, have the potential to deliver disease-course-altering treatments for central nervous system (CNS) indications. However, several clinical trials have reported severe adverse events, including patient deaths following high-dose systemic administration for muscle-directed gene transfer, highlighting the need to explore approaches utilizing lower doses when targeting the CNS. Animal models of disease provide insight into the response to new AAV therapies. However, translation from small to larger animals and eventually to humans is hampered by anatomical and biological differences across the species and their impact on AAV delivery. We performed a literature review of preclinical studies of AAV gene therapy biodistribution following cerebrospinal fluid (CSF) delivery (intracerebroventricular, intra-cisterna magna, and intrathecal lumbar). The reviewed literature varies greatly in the reported biodistribution of AAV following administration into the CSF. Differences between studies, including animal model, vector serotype used, method used to assess biodistribution, and route of administration, among other variables, contribute to differing outcomes and difficulties in translating these preclinical results. For example, only half of the published AAV-based gene therapy studies report vector copy number, the most direct readout following administration of a vector; none of these studies reported details such as the empty:full capsid ratio and quality of encapsidated genome. Analysis of the last decade's literature focusing on AAV-based gene therapies targeting the CNS underscores limitations of the body of knowledge and room for continued research. In particular, there is a need to understand the biodistribution achieved by different CSF-directed routes of administration and determining if specific cell types/structures of interest will be transduced. Our findings point to a clear need for a more systematic approach across the field to align the assessments and elements reported in preclinical research to enable more reliable translation across animal models and into human studies.
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Affiliation(s)
- Xin Chen
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Daniel A Lim
- Department of Neurological Surgery, Eli and Edythe Broad Center for Regeneration Medicine, and the Weill Institute for Neurosciences, University of California San Francisco School of Medicine, San Francisco, California, USA
| | - Michael W Lawlor
- Medical College of Wisconsin and Diverge Translational Science Laboratory, Milwaukee, Wisconsin, USA
| | - David Dimmock
- Rady Children's Institute for Genomic Medicine, San Diego, California, USA
| | - Charles H Vite
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; and
| | | | | | | | | | - Steven J Gray
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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5
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Prasad S, Dimmock DP, Greenberg B, Walia JS, Sadhu C, Tavakkoli F, Lipshutz GS. Immune Responses and Immunosuppressive Strategies for Adeno-Associated Virus-Based Gene Therapy for Treatment of Central Nervous System Disorders: Current Knowledge and Approaches. Hum Gene Ther 2022; 33:1228-1245. [PMID: 35994385 PMCID: PMC9808800 DOI: 10.1089/hum.2022.138] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Adeno-associated viruses (AAVs) are being increasingly used as gene therapy vectors in clinical studies especially targeting central nervous system (CNS) disorders. Correspondingly, host immune responses to the AAV capsid or the transgene-encoded protein have been observed in various clinical and preclinical studies. Such immune responses may adversely impact patients' health, prevent viral transduction, prevent repeated dosing strategies, eliminate transduced cells, and pose a significant barrier to the potential effectiveness of AAV gene therapy. Consequently, multiple immunomodulatory strategies have been used in attempts to limit immune-mediated responses to the vector, enable readministration of AAV gene therapy, prevent end-organ toxicity, and increase the duration of transgene-encoded protein expression. Herein we review the innate and adaptive immune responses that may occur during CNS-targeted AAV gene therapy as well as host- and treatment-specific factors that could impact the immune response. We also summarize the available preclinical and clinical data on immune responses specifically to CNS-targeted AAV gene therapy and discuss potential strategies for incorporating prophylactic immunosuppression regimens to circumvent adverse immune responses.
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Affiliation(s)
| | - David P. Dimmock
- Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, California, USA
| | - Benjamin Greenberg
- Department of Neurology, O'Donnell Brain Institute, University of Texas Southwestern, Dallas, Texas, USA
| | - Jagdeep S. Walia
- Division of Medical Genetics, Department of Pediatrics, Queen's University, Kingston, Canada
| | | | | | - Gerald S. Lipshutz
- Departments of Molecular and Medical Pharmacology and Surgery, Intellectual and Developmental Disabilities Research Center at UCLA, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Correspondence: Prof. Gerald S. Lipshutz, Departments of Molecular and Medical Pharmacology and Surgery, Intellectual and Developmental Disabilities Research Center at UCLA, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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6
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Goodspeed K, Liu JS, Nye KL, Prasad S, Sadhu C, Tavakkoli F, Bilder DA, Minassian BA, Bailey RM. SLC13A5 Deficiency Disorder: From Genetics to Gene Therapy. Genes (Basel) 2022; 13:genes13091655. [PMID: 36140822 PMCID: PMC9498415 DOI: 10.3390/genes13091655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Epileptic encephalopathies may arise from single gene variants. In recent years, next-generation sequencing technologies have enabled an explosion of gene identification in monogenic epilepsies. One such example is the epileptic encephalopathy SLC13A5 deficiency disorder, which is caused by loss of function pathogenic variants to the gene SLC13A5 that results in deficiency of the sodium/citrate cotransporter. Patients typically experience seizure onset within the first week of life and have developmental delay and intellectual disability. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and non-epileptic features of SLC13A5 deficiency disorder. Gene therapy may offer hope to these patients and better clinical outcomes than current available treatments. Here, we discuss SLC13A5 genetics, natural history, available treatments, potential outcomes and assessments, and considerations for translational medical research for an AAV9-based gene replacement therapy.
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Affiliation(s)
- Kimberly Goodspeed
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Judy S. Liu
- Warren Alpert School of Medicine, Brown University, Providence, RI 02903, USA
| | | | - Suyash Prasad
- Department of Research & Development, Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Chanchal Sadhu
- Department of Research & Development, Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Fatemeh Tavakkoli
- Department of Research & Development, Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Deborah A. Bilder
- Division of Child & Adolescent Psychiatry, Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA
| | - Berge A. Minassian
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Rachel M. Bailey
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
- Center for Alzheimer’s and Neurodegenerative Diseases, University of Texas Southwestern, Dallas, TX 75390, USA
- Correspondence: ; Tel.: +1-214-648-8510
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Goodspeed K, Bailey RM, Prasad S, Sadhu C, Cardenas JA, Holmay M, Bilder DA, Minassian BA. Gene Therapy: Novel Approaches to Targeting Monogenic Epilepsies. Front Neurol 2022; 13:805007. [PMID: 35847198 PMCID: PMC9284605 DOI: 10.3389/fneur.2022.805007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 04/20/2022] [Indexed: 11/18/2022] Open
Abstract
Genetic epilepsies are a spectrum of disorders characterized by spontaneous and recurrent seizures that can arise from an array of inherited or de novo genetic variants and disrupt normal brain development or neuronal connectivity and function. Genetically determined epilepsies, many of which are due to monogenic pathogenic variants, can result in early mortality and may present in isolation or be accompanied by neurodevelopmental disability. Despite the availability of more than 20 antiseizure medications, many patients with epilepsy fail to achieve seizure control with current therapies. Patients with refractory epilepsy—particularly of childhood onset—experience increased risk for severe disability and premature death. Further, available medications inadequately address the comorbid developmental disability. The advent of next-generation gene sequencing has uncovered genetic etiologies and revolutionized diagnostic practices for many epilepsies. Advances in the field of gene therapy also present the opportunity to address the underlying mechanism of monogenic epilepsies, many of which have only recently been described due to advances in precision medicine and biology. To bring precision medicine and genetic therapies closer to clinical applications, experimental animal models are needed that replicate human disease and reflect the complexities of these disorders. Additionally, identifying and characterizing clinical phenotypes, natural disease course, and meaningful outcome measures from epileptic and neurodevelopmental perspectives are necessary to evaluate therapies in clinical studies. Here, we discuss the range of genetically determined epilepsies, the existing challenges to effective clinical management, and the potential role gene therapy may play in transforming treatment options available for these conditions.
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Affiliation(s)
- Kimberly Goodspeed
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
| | - Rachel M. Bailey
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
- Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern, Dallas, TX, United States
| | - Suyash Prasad
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Chanchal Sadhu
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Jessica A. Cardenas
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Mary Holmay
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Deborah A. Bilder
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, United States
| | - Berge A. Minassian
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
- *Correspondence: Berge A. Minassian
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8
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Eggers M, Vannoy CH, Huang J, Purushothaman P, Brassard J, Fonck C, Meng H, Prom MJ, Lawlor MW, Cunningham J, Sadhu C, Mavilio F. Muscle-directed gene therapy corrects Pompe disease and uncovers species-specific GAA immunogenicity. EMBO Mol Med 2022; 14:e13968. [PMID: 34850579 PMCID: PMC8749482 DOI: 10.15252/emmm.202113968] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [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: 01/14/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 11/21/2022] Open
Abstract
Pompe disease is a severe disorder caused by loss of acid α-glucosidase (GAA), leading to glycogen accumulation in tissues and neuromuscular and cardiac dysfunction. Enzyme replacement therapy is the only available treatment. AT845 is an adeno-associated viral vector designed to express human GAA specifically in skeletal muscle and heart. Systemic administration of AT845 in Gaa-/- mice led to a dose-dependent increase in GAA activity, glycogen clearance in muscles and heart, and functional improvement. AT845 was tolerated in cynomolgus macaques at low doses, while high doses caused anti-GAA immune response, inflammation, and cardiac abnormalities resulting in unscheduled euthanasia of two animals. Conversely, a vector expressing the macaque GAA caused no detectable pathology, indicating that the toxicity observed with AT845 was an anti-GAA xenogeneic immune response. Western blot analysis showed abnormal processing of human GAA in cynomolgus muscle, adding to the species-specific effects of enzyme expression. Overall, these studies show that AAV-mediated GAA delivery to muscle is efficacious in Gaa-/- mice and highlight limitations in predicting the toxicity of AAV vectors encoding human proteins in non-human species.
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Affiliation(s)
- Michelle Eggers
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
| | - Charles H Vannoy
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
| | - Jianyong Huang
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
| | | | | | - Carlos Fonck
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
| | - Hui Meng
- Department of Pathology and Neuroscience Research CenterMedical College of WisconsinMilwaukeeWIUSA
| | - Mariah J Prom
- Department of Pathology and Neuroscience Research CenterMedical College of WisconsinMilwaukeeWIUSA
| | - Michael W Lawlor
- Department of Pathology and Neuroscience Research CenterMedical College of WisconsinMilwaukeeWIUSA
| | - Justine Cunningham
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
- Present address:
Sana BiotechnologySouth San FranciscoCAUSA
| | - Chanchal Sadhu
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
| | - Fulvio Mavilio
- Nonclinical, Pharmacology/ToxicologyAudentes TherapeuticsSan FranciscoCAUSA
- Department of Life SciencesUniversity of Modena and Reggio EmiliaModenaItaly
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9
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Pradhap D, Gandhi KS, Magesh NS, Peter TS, Sadhu C, Silva JD, Godson PS, Krishnakumar S, Saravanan P. Trace element concentrations and their potential ecological risk in the reef sediments of coral islands, Vembar group of islands, Gulf of Mannar, India. Mar Pollut Bull 2020; 160:111607. [PMID: 32898740 DOI: 10.1016/j.marpolbul.2020.111607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
The present work was undertaken to assess the impact of trace element concentration and the status of potential ecological risk in the reef sediments of the Vembar group of islands, Gulf of Mannar Marine National Park, India. Totally, 114 reef sediments (surface) were collected from the Vembar group of islands (Nallathanni Island - 36 samples; Upputhanni Island - 48 samples; Puluvinichalli Island-30 samples). The reef sediments are enriched with sand-sized calcareous particles. The calcium carbonate percentage (CaCO3) was primarily controlled by the distribution of coral colonies and available lithogenic grains. The pollution load index (PLI) reveals that the majority of the sediments fall under the unpolluted category. Moreover, the potential ecological risk (PERI) and sediment pollution index (SPI) reveals that the Vembar group of islands fall under the low ecological risk category.
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Affiliation(s)
- D Pradhap
- Department of Geology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
| | - K Sanjai Gandhi
- Department of Geology, PG Extension Centre, Periyar University, Dharmapuri 636701, Tamil Nadu, India
| | - N S Magesh
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Headland Sada, Vasco-da-Gama, Goa 403 804, India.
| | - T Simon Peter
- Centre for Geotechnology, Manonmaniam Sundaranar University, Tirunelveli 62701, Tamil Nadu, India
| | - C Sadhu
- Department of Geology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
| | - Judith D Silva
- Department of Energy, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
| | - Prince S Godson
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram 695581, Tamil Nadu, India
| | - S Krishnakumar
- Department of Geology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India.
| | - P Saravanan
- Department of Geology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
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Sadhu C, Hendrickson L, Dick KO, Potter TG, Staunton DE. Novel tools for functional analysis of CD11c: activation-specific, activation-independent, and activating antibodies. J Immunoassay Immunochem 2008; 29:42-57. [PMID: 18080879 DOI: 10.1080/15321810701735062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Functions and binding properties of four CD11c-specific mAbs are described here. The mAb 496B stimulated, while 496K inhibited ligand binding of CD11c. The stimulatory mAb, 496B, as well as the inhibitory mAbs BU15 and 496 K appear to act allosterically, as they do not bind the CD11c I domain. The mAb 3.9 bound preferentially to activated forms of CD11c and the binding was divalent cation dependent. CD11c binding to 3.9 recapitulates many of the integrin-ligand interactions. Our data suggest that 3.9 is a competitive antagonist, BU15 and 496K are allosteric antagonists, and 496B is an allosteric agonist of CD11c. These mAbs provide a set of tools to study the functions of the dendritic cell marker, CD11c.
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Sadhu C, Harris EAS, Staunton DE. Enhancement of Natural Killer cell cytotoxicity by a CD18 integrin-activating antibody. Biochem Biophys Res Commun 2007; 358:938-41. [PMID: 17512497 DOI: 10.1016/j.bbrc.2007.05.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [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: 04/29/2007] [Accepted: 05/06/2007] [Indexed: 11/30/2022]
Abstract
Natural Killer (NK) cells kill certain tumor cells and virus infected cells in an antigen-independent manner. Members of CD18 integrins such as CD11a, CD11b, and CD11c are expressed in all NK cells. CD18-blocking mAbs inhibit the killing activity of NK cells implying an essential role of these integrins in NK cell cytotoxicity. In this report we show that the pan CD18-activating mAb, 240Q, augments cytotoxicity of resting NK cells. Since activation of either CD11a or CD11c alone fails to augment the NK cell activity, we postulate that a functional synergy of the individual CD18 integrins is responsible for the observed stimulatory effect of pan CD18 activation on NK cell cytotoxicity.
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Affiliation(s)
- Chanchal Sadhu
- ICOS Corporation, 22021 20th Avenue SE, Bothell, WA 98021, USA.
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12
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Sadhu C, Ting HJ, Lipsky B, Hensley K, Garcia-Martinez LF, Simon SI, Staunton DE. CD11c/CD18: novel ligands and a role in delayed-type hypersensitivity. J Leukoc Biol 2007; 81:1395-403. [PMID: 17389580 DOI: 10.1189/jlb.1106680] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CD11c, a member of the leukointegrin family, is expressed prominently on tissue macrophages and dendritic cells and binds to complement fragment (iC3b), provisional matrix molecules (fibrinogen), and the Ig superfamily cell adhesion molecule, ICAM-1. CD11c has been proposed to function in phagocytosis, cell migration, and cytokine production by monocytes/macrophages as well as induction of T cell proliferation by Langerhans cells. Using assays to quantify CD11c-mediated cell adhesion, we demonstrate that CD11c recognizes ICAM-2 and VCAM-1. The CD11c-binding site on VCAM-1 appears to be different from that used by the integrin alpha4. CD11c and alpha4beta1 contributed to monocyte capture and transmigration on inflamed human aortic endothelial cells. We discovered that the anti-mouse CD11c mAb N418 blocks CD11c binding to iC3b, ICAM-1, and VCAM-1. Treatment of mice with N418 reduced SRBC-induced delayed-type hypersensitivity significantly. CD11c appeared to contribute predominantly to the sensitization phase and somewhat less to the response to SRBC challenge. This suggests a novel role for CD11c during leukocyte recruitment, antigen uptake, and the survival of APC.
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Affiliation(s)
- Chanchal Sadhu
- ICOS Corporation, 22021 20th Ave., S.E., Bothell, WA 98021, USA.
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13
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Abstract
Although members of the class I phosphoinositide 3-kinases (PI3Ks) have been implicated in neutrophil inflammatory responses, the contribution of the individual PI3K isoforms in neutrophil activation has not been tractable with the non-selective inhibitors, LY294002 and wortmannin. We have developed a novel series of PI3K inhibitors that is selective for PI3K delta, an isoform expressed predominantly in hematopoietic cells. In addition to being selective between members of class I PI3Ks, representatives of these inhibitors such as IC980033 and IC87114 did not inhibit any protein kinases tested. Utilizing these inhibitors we report here a novel role for PI3K delta in neutrophil activation. Inhibition of PI3K delta with IC980033 and IC87114 blocked both fMLP- and TNF1 alpha-induced neutrophil superoxide generation and elastase exocytosis. The PI3K delta inhibitor IC87114 also blocked TNF1 alpha-stimulated elastase exocytosis from neutrophils in a mouse model of inflammation. To our knowledge, this is the first in vivo efficacy demonstration of a PI3K delta inhibitor in an animal model. Inhibition of PI3K delta, however, had no effect on in vitro neutrophil bactericidal activity and Fc gamma R-stimulated superoxide generation. Thus, PI3K delta plays an essential role in certain signaling pathways of neutrophil activation and appears to be an attractive target for the development of an anti-inflammatory therapeutic.
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Affiliation(s)
- Chanchal Sadhu
- ICOS Corporation, 22021 20th Avenue SE, Bothell, WA 98021, USA.
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Sadhu C, Masinovsky B, Dick K, Sowell CG, Staunton DE. Essential role of phosphoinositide 3-kinase delta in neutrophil directional movement. J Immunol 2003; 170:2647-54. [PMID: 12594293 DOI: 10.4049/jimmunol.170.5.2647] [Citation(s) in RCA: 301] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Neutrophil chemotaxis is a critical component of the innate immune response. Neutrophils can sense an extremely shallow gradient of chemoattractants and produce relatively robust chemotactic behavior. This directional migration requires cell polarization with actin polymerization occurring predominantly in the leading edge. Synthesis of phosphatidylinositol (3,4,5) trisphosphate (PIP3) by phosphoinositide 3-kinase (PI3K) contributes to asymmetric F-actin synthesis and cell polarization during neutrophil chemotaxis. To determine the contribution of the hemopoietic cell-restricted PI3K delta in neutrophil chemotaxis, we have developed a potent and selective PI3K delta inhibitor, IC87114. IC87114 inhibited polarized morphology of neutrophils, fMLP-stimulated PIP3 production and chemotaxis. Tracking analysis of IC87114-treated neutrophils indicated that PI3K delta activity was required for the directional component of chemotaxis, but not for random movement. Inhibition of PI3K delta, however, did not block F-actin synthesis or neutrophil adhesion. These results demonstrate that PI3K delta can play a selective role in the amplification of PIP3 levels that lead to neutrophil polarization and directional migration.
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Sadhu C, Masinovsky B, Staunton DE. Differential regulation of chemoattractant-stimulated beta 2, beta 3, and beta 7 integrin activity. J Immunol 1998; 160:5622-8. [PMID: 9605168] [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] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Leukocyte adhesion to endothelium and extravasation are dynamic processes that require activation of integrins. Chemoattractants such as IL-8 and FMLP are potent activators of leukocyte integrins. To compare the chemoattractant-stimulated activation of three integrins, alpha 4 beta 7, alpha L beta 2, and alpha V beta 3, in the same cellular context, we expressed an IL-8 receptor (IL-8RA) and FMLP receptor (FPR) in the lymphoid cell line JY. Chemoattractants induced a rapid increase in alpha L beta 2- and alpha V beta 3-dependent JY adhesion within 5 min, and it was sustained for 30 min. In contrast, stimulation of alpha 4 beta 7-dependent adhesion was transient, returning to basal levels by 30 min. The activation profiles of the integrins were similar regardless of whether IL-8 or FMLP was used for induction. We also demonstrate that alpha 4 beta 7-dependent adhesion was uniquely responsive to the F actin-disrupting agent cytochalasin D and the protein kinase C (PKC) inhibitor chelerythrin. While alpha V beta 3- and alpha L beta 2-mediated cell adhesion was significantly reduced by cytochalasin D, alpha 4 beta 7-mediated adhesion was enhanced. Chelerythrin inhibited both the IL-8 and PMA activation of alpha L beta 2 and alpha V beta 3. In contrast, inducible alpha 4 beta 7 activity was unaffected, and basal activity was increased. These findings demonstrate that the mechanism of alpha 4 beta 7 regulation by chemoattractants is different from that of alpha L beta 2 and alpha V beta 3 and that it appears to involve distinct cytoskeletal and PKC dependencies. In addition, PKC activity may be a positive or negative regulator of integrin-dependent adhesion.
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MESH Headings
- Antigens, CD/biosynthesis
- B-Lymphocytes
- Cell Adhesion/drug effects
- Cell Line, Transformed
- Cytochalasin D/pharmacology
- Humans
- Integrins/drug effects
- Integrins/metabolism
- Integrins/physiology
- Interleukin-8/metabolism
- Interleukin-8/pharmacology
- Lymphocyte Function-Associated Antigen-1/drug effects
- Lymphocyte Function-Associated Antigen-1/metabolism
- Lymphocyte Function-Associated Antigen-1/physiology
- N-Formylmethionine Leucyl-Phenylalanine/metabolism
- N-Formylmethionine Leucyl-Phenylalanine/pharmacology
- Protein Kinase C/physiology
- Receptors, Formyl Peptide
- Receptors, Immunologic/biosynthesis
- Receptors, Interleukin/biosynthesis
- Receptors, Interleukin-8A
- Receptors, Peptide/biosynthesis
- Receptors, Vitronectin/drug effects
- Receptors, Vitronectin/metabolism
- Receptors, Vitronectin/physiology
- Transfection/immunology
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Affiliation(s)
- C Sadhu
- ICOS Corporation, Bothell, WA 98021, USA
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16
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Sadhu C, Masinovsky B, Staunton DE. Differential Regulation of Chemoattractant-Stimulated β2, β3, and β7 Integrin Activity. The Journal of Immunology 1998. [DOI: 10.4049/jimmunol.160.11.5622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Leukocyte adhesion to endothelium and extravasation are dynamic processes that require activation of integrins. Chemoattractants such as IL-8 and FMLP are potent activators of leukocyte integrins. To compare the chemoattractant-stimulated activation of three integrins, α4β7, αLβ2, and αVβ3, in the same cellular context, we expressed an IL-8 receptor (IL-8RA) and FMLP receptor (FPR) in the lymphoid cell line JY. Chemoattractants induced a rapid increase in αLβ2- and αVβ3-dependent JY adhesion within 5 min, and it was sustained for 30 min. In contrast, stimulation of α4β7-dependent adhesion was transient, returning to basal levels by 30 min. The activation profiles of the integrins were similar regardless of whether IL-8 or FMLP was used for induction. We also demonstrate that α4β7-dependent adhesion was uniquely responsive to the F actin-disrupting agent cytochalasin D and the protein kinase C (PKC) inhibitor chelerythrin. While αVβ3- and αLβ2-mediated cell adhesion was significantly reduced by cytochalasin D, α4β7-mediated adhesion was enhanced. Chelerythrin inhibited both the IL-8 and PMA activation of αLβ2 and αVβ3. In contrast, inducible α4β7 activity was unaffected, and basal activity was increased. These findings demonstrate that the mechanism of α4β7 regulation by chemoattractants is different from that of αLβ2 and αVβ3 and that it appears to involve distinct cytoskeletal and PKC dependencies. In addition, PKC activity may be a positive or negative regulator of integrin-dependent adhesion.
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17
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Sadhu C, Lipsky B, Erickson HP, Hayflick J, Dick KO, Gallatin WM, Staunton DE. LFA-1 binding site in ICAM-3 contains a conserved motif and non-contiguous amino acids. Cell Adhes Commun 1994; 2:429-40. [PMID: 7531103 DOI: 10.3109/15419069409004453] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The intercellular adhesion molecule-3 (ICAM-3) is a counter receptor for the integrin LFA-1 that supports cell-cell adhesion dependent functions. ICAM-3 is a member of the immunoglobulin superfamily possessing five immunoglobulin-like domains. Here, we characterize the overall shape of ICAM-3 and the amino acid residues involved in binding LFA-1 and monoclonal antibodies (Mab). Electron microscopic observations show that ICAM-3 is predominantly a straight rod of 15 nm in length, suggesting a head to tail arrangement of the immunoglobulin-like domains. Six out of nine ICAM-3 Mab described blocked the interaction with LFA-1 to varying degrees. Domain assignment of blocking Mab epitopes and characterization of LFA-1-dependent cell adhesion to ICAM-3 mutants demonstrate that the amino-terminal domain of ICAM-3 interacts with LFA-1. A conserved amino acid motif including residues E37 and T38 form an integrin binding site (IBS) in ICAM-3. This motif has also been shown to function as an IBS in ICAM-3 and VCAM-1 and hence many form a common site of contact in all CAMs of this type. Other ICAM-3 residues critical to adhesive interactions, such as Q75, conserved in ICAM-1 and ICAM-2, but not VCAM-1, may confer specificity to LFA-1 binding. This residue, Q75, is predicted to locate in a model of ICAM-3 to the same site as RGD in the immunoglobulin-like domain of fibronectin that binds several integrins. This suggest an evolutionary relationship between ICAMs and fibronectin interactions with integrins.
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Affiliation(s)
- C Sadhu
- ICOS Corporation, Bothell, WA 98021
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18
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Sadhu C, Hoekstra D, McEachern MJ, Reed SI, Hicks JB. A G-protein alpha subunit from asexual Candida albicans functions in the mating signal transduction pathway of Saccharomyces cerevisiae and is regulated by the a1-alpha 2 repressor. Mol Cell Biol 1992; 12:1977-85. [PMID: 1569935 PMCID: PMC364368 DOI: 10.1128/mcb.12.5.1977-1985.1992] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We have isolated a gene, designated CAG1, from Candida albicans by using the G-protein alpha-subunit clone SCG1 of Saccharomyces cerevisiae as a probe. Amino acid sequence comparison revealed that CAG1 is more homologous to SCG1 than to any other G protein reported so far. Homology between CAG1 and SCG1 not only includes the conserved guanine nucleotide binding domains but also spans the normally variable regions which are thought to be involved in interaction with the components of the specific signal transduction pathway. Furthermore, CAG1 contains a central domain, previously found only in SCG1. cag1 null mutants of C. albicans created by gene disruption produced no readily detectable phenotype. The C. albicans CAG1 gene complemented both the growth and mating defects of S. cerevisiae scg1 null mutants when carried on either a low- or high-copy-number plasmid. In diploid C. albicans, the CAG1 transcript was readily detectable in mycelial and yeast cells of both the white and opaque forms. However, the CAG1-specific transcript in S. cerevisiae transformants containing the C. albicans CAG1 gene was observed only in haploid cells. This transcription pattern matches that of SCG1 in S. cerevisiae and is caused by a1-alpha 2 mediated repression in diploid cells. That is, CAG1 behaves as a haploid-specific gene in S. cerevisiae, subject to control by the a1-alpha 2 mating-type regulation pathway. We infer from these results that C. albicans may have a signal transduction system analogous to that controlling mating type in S. cerevisiae or possibly even a sexual pathway that has so far remained undetected.
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Affiliation(s)
- C Sadhu
- Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, California 92037
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19
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Abstract
During the initial 4 h of treatment, copper and zinc similarly activated the rates of transcription and mRNA accumulation from the two human metallothionein (MT) genes, viz., MTI-G and MTII-A, in the hepatoblastoma cell line HepG2. The levels of copper-induced MT mRNAs remained at a plateau for up to 15 h. In contrast, the levels of zinc-induced MT mRNAs gradually declined after about 4 h, despite substantial transcription. The decrease in the zinc-induced MT mRNA half-life is probably due to a posttranscriptional event(s).
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Affiliation(s)
- C Sadhu
- Department of Biological Sciences, University of Calgary, Alberta, Canada
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20
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Choi HT, Revuelta JL, Sadhu C, Jayaram M. Structural organization of the TRP1 gene of Phycomyces blakesleeanus: implications for evolutionary gene fusion in fungi. Gene 1988; 71:85-95. [PMID: 3215529 DOI: 10.1016/0378-1119(88)90080-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The complete nucleotide (nt) sequence of the cloned TRP1 gene from Phycomyces blakesleeanus is reported. The gene encodes a trifunctional polypeptide that represents a sequential fusion of glutamine amidotransferase (TrpG), indoleglycerolphosphate synthetase (TrpC), and phosphoribosylanthranilate isomerase (TrpF) activities from the amino- to the carboxy terminus. This genetic organization is characteristic of filamentous fungi in general. The transcription start sites and the polyadenylation sites of the gene have been mapped. The two predominant TRP1 transcripts have a short leader of 13 and 18 nt, while minor species with significantly longer leaders are also detectable. Approximately 50 bp and 70 bp upstream from the major transcription start points, sequences that match the canonical eukaryotic TATA and CAAT boxes, respectively, are found. Two major polyadenylation signals are located approximately 50 and 70 nt downstream from the translational stop. Three closely clustered minor polyadenylation sites map to roughly 120-150 bp 3' to the termination codon. The TRP1 gene is the first and only Phycomyces gene that has been cloned and sequenced. The information regarding the promoter and terminator of a Phycomyces gene derived from these studies should benefit strategies aimed at gene manipulations in this organism.
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Affiliation(s)
- H T Choi
- Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037
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21
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Sadhu C, Gedamu L. Regulation of human metallothionein (MT) genes. Differential expression of MTI-F, MTI-G, and MTII-A genes in the hepatoblastoma cell line (HepG2). J Biol Chem 1988; 263:2679-84. [PMID: 2830259] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have analyzed the pattern of expression of three human metallothionein (MT) genes (MTI-F, MTI-G, and MTII-A) in the hepatoblastoma cell line, HepG2, in response to the metal ion inducers cadmium, copper, and zinc. The absolute number of transcripts of each of the three genes were measured, and the data clearly suggest differential regulation of these members of the MT gene family by the different inducers both in terms of the rate and the extent of transcript accumulation. The lowest levels of transcript accumulation was observed for MTI-F gene (maximum 4,000 molecules of mRNA per cell) and copper was shown to be its poorest inducer (up to 2,000 molecules per cell). Cadmium is the poorest inducer of MTI-G gene even though transcripts of this gene accumulated at comparatively higher levels than those of MTI-F. Copper- and zinc-induced MTI-G transcript accumulation was up to 12,000 molecules per cell whereas the corresponding value for cadmium was only 4,500. MTII-A was the only gene expressed in the absence of any externally added inducer. Also, in contrast to the MTI genes, the MTII-A gene was equally responsive to all the metal ions tested and the induced levels of accumulation were much higher (up to 75,000 molecules of MTII-A mRNA per cell).
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Affiliation(s)
- C Sadhu
- Department of Biological Sciences, University of Calgary, Alberta, Canada
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22
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Sadhu C, Gedamu L. Regulation of human metallothionein (MT) genes. Differential expression of MTI-F, MTI-G, and MTII-A genes in the hepatoblastoma cell line (HepG2). J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)69121-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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23
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Sadhu C, Gedamu L. A procedure for the preparation of RNA-free plasmid DNA. Biotechniques 1988; 6:20-1. [PMID: 2483654] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- C Sadhu
- Dept. of Biological Sciences, University of Calgary, Alberta, Canada
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25
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Sadhu C, Gedamu L. In vitro synthesis of double stranded RNA and measurement of thermal stability: effect of base composition, formamide and ionic strength. Biochem Int 1987; 14:1015-22. [PMID: 2839182] [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] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Double stranded RNA was prepared by transcription of complementary strands followed by annealing. RNA duplexes prepared in this way showed cooperative thermal transition. Thermal denaturation of RNA duplexes of 33%-70% G+C content shows that Tm increases more sharply [0.93 degrees C/(%G+C)] with increase in G+C than that of DNA. Formamide (up to 80%) reduces Tm of RNA duplex linearly, and the rate of reduction is much less than that of DNA. The relation between salt concentration and Tm of double stranded RNA was also determined. The following relationship has been derived based on the above observations: Tm (ds RNA) = 14.88 logM + 0.93 (%G+C) + 67.62 - 0.4 (%Formamide).
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Affiliation(s)
- C Sadhu
- Department of Biology, University of Calgary, Alberta, Canada
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Sadhu C, Dutta S, Gopinathan KP. Presence of mycobacteriophage I3-like DNA sequences in the genome of its host Mycobacterium smegmatis. Arch Microbiol 1986; 146:166-9. [PMID: 3800555 DOI: 10.1007/bf00402345] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The genomes of phage I3 and its host Mycobacterium smegmatis have been compared. From thermal melting studies the GC contents of DNA from mycobacteriophage I3 and its host M. smegmatis were found to be 66%. A new method, based only on the initial rates of reassociation, has been developed for calculating the DNA homology. Analysis of DNA reassociation kinetics suggested the presence of one equivalent of the phage I3 genome within the M. smegmatis genome. Southern analysis revealed the presence of almost all of the phage I3 specific sequences within the host genome.
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27
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Sadhu C, Gope ML, Sadhu K, Gopinathan KP. Isolation, characterization and mapping of temperature-sensitive mutants of mycobacteriophage I3. J Biosci 1985. [DOI: 10.1007/bf02716765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
The optimal parameters in the use of nuclease S1 in DNA reassociation kinetics in the presence of formamide have been determined. The conditions are especially suitable for the study of DNA rich in mole percent GC. A 10-fold dilution of the reassociation samples leading to a decrease in both NaCl and formamide concentrations, consequently resulting in a lowering of Tm by only 1.5 degree C, and the S1 digestion at temperatures identical to the reassociation assay in order to retain the stability of the duplex, are two important aspects of this system. Under these conditions, the kinetics of reassociation followed the theoretically predicted pattern, while the earlier reported methods have shown lower values.
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