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Lee HHC, Latzer IT, Bertoldi M, Gao G, Pearl PL, Sahin M, Rotenberg A. Gene replacement therapies for inherited disorders of neurotransmission: Current progress in succinic semialdehyde dehydrogenase deficiency. J Inherit Metab Dis 2024; 47:476-493. [PMID: 38581234 PMCID: PMC11096052 DOI: 10.1002/jimd.12735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 03/06/2024] [Accepted: 03/20/2024] [Indexed: 04/08/2024]
Abstract
Neurodevelopment is a highly organized and complex process involving lasting and often irreversible changes in the central nervous system. Inherited disorders of neurotransmission (IDNT) are a group of genetic disorders where neurotransmission is primarily affected, resulting in abnormal brain development from early life, manifest as neurodevelopmental disorders and other chronic conditions. In principle, IDNT (particularly those of monogenic causes) are amenable to gene replacement therapy via precise genetic correction. However, practical challenges for gene replacement therapy remain major hurdles for its translation from bench to bedside. We discuss key considerations for the development of gene replacement therapies for IDNT. As an example, we describe our ongoing work on gene replacement therapy for succinic semialdehyde dehydrogenase deficiency, a GABA catabolic disorder.
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Affiliation(s)
- Henry HC Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Itay Tokatly Latzer
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA
- Tel-Aviv University Faculty of Medicine, Tel-Aviv, Israel
| | - Mariarita Bertoldi
- Dept. of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Guangping Gao
- The Horae Gene Therapy Center, UMass Medical School, MA 01605, USA
| | - Phillip L Pearl
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Alexander Rotenberg
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA
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2
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Li L, Vasan L, Kartono B, Clifford K, Attarpour A, Sharma R, Mandrozos M, Kim A, Zhao W, Belotserkovsky A, Verkuyl C, Schmitt-Ulms G. Advances in Recombinant Adeno-Associated Virus Vectors for Neurodegenerative Diseases. Biomedicines 2023; 11:2725. [PMID: 37893099 PMCID: PMC10603849 DOI: 10.3390/biomedicines11102725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors are gene therapy delivery tools that offer a promising platform for the treatment of neurodegenerative diseases. Keeping up with developments in this fast-moving area of research is a challenge. This review was thus written with the intention to introduce this field of study to those who are new to it and direct others who are struggling to stay abreast of the literature towards notable recent studies. In ten sections, we briefly highlight early milestones within this field and its first clinical success stories. We showcase current clinical trials, which focus on gene replacement, gene augmentation, or gene suppression strategies. Next, we discuss ongoing efforts to improve the tropism of rAAV vectors for brain applications and introduce pre-clinical research directed toward harnessing rAAV vectors for gene editing applications. Subsequently, we present common genetic elements coded by the single-stranded DNA of rAAV vectors, their so-called payloads. Our focus is on recent advances that are bound to increase treatment efficacies. As needed, we included studies outside the neurodegenerative disease field that showcased improved pre-clinical designs of all-in-one rAAV vectors for gene editing applications. Finally, we discuss risks associated with off-target effects and inadvertent immunogenicity that these technologies harbor as well as the mitigation strategies available to date to make their application safer.
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Affiliation(s)
- Leyao Li
- Department of Biochemistry, University of Toronto, Medical Sciences Building, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
| | - Lakshmy Vasan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Bryan Kartono
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Kevan Clifford
- Institute of Medical Science, University of Toronto, Medical Sciences Building, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
- Centre for Addiction and Mental Health (CAMH), 250 College St., Toronto, ON M5T 1R8, Canada
| | - Ahmadreza Attarpour
- Department of Medical Biophysics, University of Toronto, 101 College St., Toronto, ON M5G 1L7, Canada
| | - Raghav Sharma
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Matthew Mandrozos
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Ain Kim
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Wenda Zhao
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Ari Belotserkovsky
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Claire Verkuyl
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, 6th Floor, 60 Leonard Avenue, Toronto, ON M5T 0S8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Medical Sciences Building, 6th Floor, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
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Wood EH, Kreymerman A, Kowal T, Buickians D, Sun Y, Muscat S, Mercola M, Moshfeghi DM, Goldberg JL. Cellular and subcellular optogenetic approaches towards neuroprotection and vision restoration. Prog Retin Eye Res 2023; 96:101153. [PMID: 36503723 PMCID: PMC10247900 DOI: 10.1016/j.preteyeres.2022.101153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 11/27/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
Optogenetics is defined as the combination of genetic and optical methods to induce or inhibit well-defined events in isolated cells, tissues, or animals. While optogenetics within ophthalmology has been primarily applied towards treating inherited retinal disease, there are a myriad of other applications that hold great promise for a variety of eye diseases including cellular regeneration, modulation of mitochondria and metabolism, regulation of intraocular pressure, and pain control. Supported by primary data from the authors' work with in vitro and in vivo applications, we introduce a novel approach to metabolic regulation, Opsins to Restore Cellular ATP (ORCA). We review the fundamental constructs for ophthalmic optogenetics, present current therapeutic approaches and clinical trials, and discuss the future of subcellular and signaling pathway applications for neuroprotection and vision restoration.
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Affiliation(s)
- Edward H Wood
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Alexander Kreymerman
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Tia Kowal
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - David Buickians
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Sun
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Stephanie Muscat
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Mark Mercola
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Darius M Moshfeghi
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA.
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Ghauri MS, Ou L. AAV Engineering for Improving Tropism to the Central Nervous System. BIOLOGY 2023; 12:biology12020186. [PMID: 36829465 PMCID: PMC9953251 DOI: 10.3390/biology12020186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023]
Abstract
Adeno-associated virus (AAV) is a non-pathogenic virus that mainly infects primates with the help of adenoviruses. AAV is being widely used as a delivery vector for in vivo gene therapy, as evidenced by five currently approved drugs and more than 255 clinical trials across the world. Due to its relatively low immunogenicity and toxicity, sustained efficacy, and broad tropism, AAV holds great promise for treating many indications, including central nervous system (CNS), ocular, muscular, and liver diseases. However, low delivery efficiency, especially for the CNS due to the blood-brain barrier (BBB), remains a significant challenge for more clinical application of AAV gene therapy. Thus, there is an urgent need for utilizing AAV engineering to discover next-generation capsids with improved properties, e.g., enhanced BBB penetrance, lower immunogenicity, and higher packaging efficiency. AAV engineering methods, including directed evolution, rational design, and in silico design, have been developed, resulting in the discovery of novel capsids (e.g., PhP.B, B10, PAL1A/B/C). In this review, we discuss key studies that identified engineered CNS capsids and/or established methodological improvements. Further, we also discussed important issues that need to be addressed, including cross-species translatability, cell specificity, and modular engineering to improve multiple properties simultaneously.
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Affiliation(s)
- Muhammad S. Ghauri
- School of Medicine, California University of Science and Medicine, Colton, CA 92324, USA
| | - Li Ou
- Genemagic Biosciences, Media, PA 19086, USA
- Department of Pediatrics, University of Minnesota, Minneapolis, MN 55454, USA
- Correspondence:
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5
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Dreismann AK, Hallam TM, Tam LC, Nguyen CV, Hughes JP, Ellis S, Harris CL. Gene targeting as a therapeutic avenue in diseases mediated by the complement alternative pathway. Immunol Rev 2023; 313:402-419. [PMID: 36369963 PMCID: PMC10099504 DOI: 10.1111/imr.13149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The complement alternative pathway (AP) is implicated in numerous diseases affecting many organs, ranging from the rare hematological disease paroxysmal nocturnal hemoglobinuria (PNH), to the common blinding disease age-related macular degeneration (AMD). Critically, the AP amplifies any activating trigger driving a downstream inflammatory response; thus, components of the pathway have become targets for drugs of varying modality. Recent validation from clinical trials using drug modalities such as inhibitory antibodies has paved the path for gene targeting of the AP or downstream effectors. Gene targeting in the complement field currently focuses on supplementation or suppression of complement regulators in AMD and PNH, largely because the eye and liver are highly amenable to drug delivery through local (eye) or systemic (liver) routes. Targeting the liver could facilitate treatment of numerous diseases as this organ generates most of the systemic complement pool. This review explains key concepts of RNA and DNA targeting and discusses assets in clinical development for the treatment of diseases driven by the alternative pathway, including the RNA-targeting therapeutics ALN-CC5, ARO-C3, and IONIS-FB-LRX, and the gene therapies GT005 and HMR59. These therapies are but the spearhead of potential drug candidates that might revolutionize the field in coming years.
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6
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Ewaisha R, Anderson KS. Immunogenicity of CRISPR therapeutics-Critical considerations for clinical translation. Front Bioeng Biotechnol 2023; 11:1138596. [PMID: 36873375 PMCID: PMC9978118 DOI: 10.3389/fbioe.2023.1138596] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/06/2023] [Indexed: 02/18/2023] Open
Abstract
CRISPR offers new hope for many patients and promises to transform the way we think of future therapies. Ensuring safety of CRISPR therapeutics is a top priority for clinical translation and specific recommendations have been recently released by the FDA. Rapid progress in the preclinical and clinical development of CRISPR therapeutics leverages years of experience with gene therapy successes and failures. Adverse events due to immunogenicity have been a major setback that has impacted the field of gene therapy. As several in vivo CRISPR clinical trials make progress, the challenge of immunogenicity remains a significant roadblock to the clinical availability and utility of CRISPR therapeutics. In this review, we examine what is currently known about the immunogenicity of CRISPR therapeutics and discuss several considerations to mitigate immunogenicity for the design of safe and clinically translatable CRISPR therapeutics.
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Affiliation(s)
- Radwa Ewaisha
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.,Department of Microbiology and Immunology, School of Pharmacy, Newgiza University, Newgiza, Egypt
| | - Karen S Anderson
- Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, AZ, United States
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7
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Rybarikova M, Almacellas Barbanoj A, Schorge S, Déglon N. CNS gene therapy: present developments and emerging trends accelerating industry-academia pathways. Hum Gene Ther 2022; 33:913-922. [PMID: 36070435 DOI: 10.1089/hum.2022.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The recent success of first central nervous system gene therapies has reinvigorated the growing community of gene therapy researchers and strengthened the field's market position. We are witnessing an increase of clinical trials with long-term efficiency mainly for neurometabolic, neurodegenerative and neurodevelopmental diseases caused by loss-of-function mutations. The ever-expanding knowledge and accessibility to the most advanced tools allow enrichment of applications to more complex diseases. This gradually contributes towards sealing the gap between top diseases impacting current global health and those towards which gene therapy development is currently aimed. Here, we highlight innovative therapeutic approaches that have reached the clinics and outline the latest improvements of vector design and targeting. Finally, we address the pressing challenges faced by clinical trials and the direction they are heading.
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Affiliation(s)
- Margareta Rybarikova
- Lausanne University Hospital, Department of Clinical Neurosciences, Lausanne, Vaud, Switzerland.,Lausanne University Hospital, Neuroscience Research Center , Lausanne, Vaud, Switzerland;
| | - Amanda Almacellas Barbanoj
- University College London, Institute of Neurology (IoN), Department of Clinical and Experimental Epilepsy (DCEE), London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Stephanie Schorge
- University College London, Institute of Neurology (IoN), Department of Clinical and Experimental Epilepsy (DCEE), London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Nicole Déglon
- Lausanne University Hospital, Department of Clinical Neurosciences, Lausanne, Vaud, Switzerland.,Lausanne University Hospital, Neuroscience Research Center, Lausanne, Vaud, Switzerland;
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Zhao Z, Kim J, Suja VC, Kapate N, Gao Y, Guo J, Muzykantov VR, Mitragotri S. Red Blood Cell Anchoring Enables Targeted Transduction and Re-Administration of AAV-Mediated Gene Therapy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201293. [PMID: 35780495 PMCID: PMC9404386 DOI: 10.1002/advs.202201293] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/14/2022] [Indexed: 05/09/2023]
Abstract
Adeno-associated virus (AAV)-mediated gene therapy is a promising therapeutic modality for curing many diseases including monogenic diseases. However, limited tissue-targeting and restricted re-administration due to the vector immunogenicity largely restrict its therapeutic potential. Here, using a red blood cell (RBC) as the carrier vehicle for AAV is demonstrated to improve its tissue-targeted transduction and enable its re-administration. Anchoring AAV to the RBC surface minimally affected its infectability toward endothelial cells. Meanwhile, AAV anchored onto RBCs is predominantly delivered to and shows efficient transduction in the lungs by virtue of the biophysical features of RBCs. RBC-anchored AAVs lead to a four- to five-fold enhancement in target gene expression in the lungsas compared to free AAVs following a single- or dual-dosing regimen. While RBC anchoring does not prevent the induction of adaptive immune responses against AAV, it results in successful transgene expression upon re-administration following prior AAV exposure. The ability to re-administer is partially attributed to the delayed and reduced AAV neutralization by neutralizing antibodies, resulting from the combination of limited exposure of physically confined AAVs and the short time required to reach the lungs. This study's findings suggest that the RBC-mediated approach is a promising strategy for repetitive, targeted AAV gene therapy.
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Affiliation(s)
- Zongmin Zhao
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
- Present address:
Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Illinois ChicagoChicagoIL60612USA
| | - Jayoung Kim
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
| | - Vinny Chandran Suja
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
| | - Neha Kapate
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
- Harvard‐MIT Division of Health Sciences and TechnologyMassachusetts Institute of TechnologyCambridgeMA02139USA
| | - Yongsheng Gao
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
| | - Junling Guo
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
| | - Vladimir R. Muzykantov
- Department of Systems Pharmacology and Translational Therapeutics and Center for Translational Targeted Therapeutics and NanomedicinePerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPA19104USA
| | - Samir Mitragotri
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMA02138USA
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonMA02115USA
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Becker J, Fakhiri J, Grimm D. Fantastic AAV Gene Therapy Vectors and How to Find Them—Random Diversification, Rational Design and Machine Learning. Pathogens 2022; 11:pathogens11070756. [PMID: 35890005 PMCID: PMC9318892 DOI: 10.3390/pathogens11070756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
Parvoviruses are a diverse family of small, non-enveloped DNA viruses that infect a wide variety of species, tissues and cell types. For over half a century, their intriguing biology and pathophysiology has fueled intensive research aimed at dissecting the underlying viral and cellular mechanisms. Concurrently, their broad host specificity (tropism) has motivated efforts to develop parvoviruses as gene delivery vectors for human cancer or gene therapy applications. While the sum of preclinical and clinical data consistently demonstrates the great potential of these vectors, these findings also illustrate the importance of enhancing and restricting in vivo transgene expression in desired cell types. To this end, major progress has been made especially with vectors based on Adeno-associated virus (AAV), whose capsid is highly amenable to bioengineering, repurposing and expansion of its natural tropism. Here, we provide an overview of the state-of-the-art approaches to create new AAV variants with higher specificity and efficiency of gene transfer in on-target cells. We first review traditional and novel directed evolution approaches, including high-throughput screening of AAV capsid libraries. Next, we discuss programmable receptor-mediated targeting with a focus on two recent technologies that utilize high-affinity binders. Finally, we highlight one of the latest stratagems for rational AAV vector characterization and optimization, namely, machine learning, which promises to facilitate and accelerate the identification of next-generation, safe and precise gene delivery vehicles.
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Affiliation(s)
- Jonas Becker
- Department of Infectious Diseases/Virology, Medical Faculty, University of Heidelberg, Center for Integrative Infectious Diseases Research (CIID), BioQuant, 69120 Heidelberg, Germany;
- Faculty of Biosciences, University of Heidelberg, 69120 Heidelberg, Germany
| | - Julia Fakhiri
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Munich, Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg, Germany
- Correspondence: (J.F.); (D.G.); Tel.: +49-174-3486203 (J.F.); +49-6221-5451331 (D.G.)
| | - Dirk Grimm
- Department of Infectious Diseases/Virology, Medical Faculty, University of Heidelberg, Center for Integrative Infectious Diseases Research (CIID), BioQuant, 69120 Heidelberg, Germany;
- German Center for Infection Research (DZIF), Partner Site Heidelberg, 69120 Heidelberg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg, 69120 Heidelberg, Germany
- Correspondence: (J.F.); (D.G.); Tel.: +49-174-3486203 (J.F.); +49-6221-5451331 (D.G.)
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10
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Sandbrink JB, Alley EC, Watson MC, Koblentz GD, Esvelt KM. Insidious Insights: Implications of viral vector engineering for pathogen enhancement. Gene Ther 2022; 30:407-410. [PMID: 35264741 DOI: 10.1038/s41434-021-00312-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/02/2021] [Accepted: 12/07/2021] [Indexed: 11/09/2022]
Abstract
Optimizing viral vectors and their properties will be important for improving the effectiveness and safety of clinical gene therapy. However, such research may generate dual-use insights relevant to the enhancement of pandemic pathogens. In particular, reliable and generalizable methods of immune evasion could increase viral fitness sufficient to cause a new pandemic. High potential for misuse is associated with (1) the development of universal genetic elements for immune modulation, (2) specific insights on capsid engineering for antibody evasion applicable to viruses with pandemic potential, and (3) the development of computational methods to inform capsid engineering. These risks may be mitigated by prioritizing non-viral delivery systems, pharmacological immune modulation methods, non-genetic vector surface modifications, and engineering methods specific to AAV and other viruses incapable of unassisted human-to-human transmission. We recommend that computational vector engineering and the publication of associated code and data be limited to AAV until a technical solution for preventing malicious access to viral engineering tools has been established.
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Affiliation(s)
- Jonas B Sandbrink
- Nuffield Department of Medicine, University of Oxford, Oxford, UK. .,Future of Humanity Institute, University of Oxford, Oxford, UK.
| | - Ethan C Alley
- Media Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Matthew C Watson
- Center for Health Security, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Gregory D Koblentz
- Schar School of Policy and Government, George Mason University, Fairfax, VA, USA
| | - Kevin M Esvelt
- Media Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
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11
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Fischell JM, Fishman PS. A Multifaceted Approach to Optimizing AAV Delivery to the Brain for the Treatment of Neurodegenerative Diseases. Front Neurosci 2021; 15:747726. [PMID: 34630029 PMCID: PMC8497810 DOI: 10.3389/fnins.2021.747726] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/31/2021] [Indexed: 12/12/2022] Open
Abstract
Despite major advancements in gene therapy technologies, there are no approved gene therapies for diseases which predominantly effect the brain. Adeno-associated virus (AAV) vectors have emerged as the most effective delivery vector for gene therapy owing to their simplicity, wide spread transduction and low immunogenicity. Unfortunately, the blood-brain barrier (BBB) makes IV delivery of AAVs, to the brain highly inefficient. At IV doses capable of widespread expression in the brain, there is a significant risk of severe immune-mediated toxicity. Direct intracerebral injection of vectors is being attempted. However, this method is invasive, and only provides localized delivery for diseases known to afflict the brain globally. More advanced methods for AAV delivery will likely be required for safe and effective gene therapy to the brain. Each step in AAV delivery, including delivery route, BBB transduction, cellular tropism and transgene expression provide opportunities for innovative solutions to optimize delivery efficiency. Intra-arterial delivery with mannitol, focused ultrasound, optimized AAV capsid evolution with machine learning algorithms, synthetic promotors are all examples of advanced strategies which have been developed in pre-clinical models, yet none are being investigated in clinical trials. This manuscript seeks to review these technological advancements, and others, to improve AAV delivery to the brain, and to propose novel strategies to build upon this research. Ultimately, it is hoped that the optimization of AAV delivery will allow for the human translation of many gene therapies for neurodegenerative and other neurologic diseases.
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Affiliation(s)
- Jonathan M Fischell
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Paul S Fishman
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
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