1
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Optogenetic restoration of high sensitivity vision with bReaChES, a red-shifted channelrhodopsin. Sci Rep 2022; 12:19312. [PMID: 36369267 PMCID: PMC9652428 DOI: 10.1038/s41598-022-23572-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022] Open
Abstract
The common final pathway to blindness in many forms of retinal degeneration is the death of the light-sensitive primary retinal neurons. However, the normally light-insensitive second- and third-order neurons persist optogenetic gene therapy aims to restore sight by rendering such neurons light-sensitive. Here, we investigate whether bReaChES, a newly described high sensitivity Type I opsin with peak sensitivity to long-wavelength visible light, can restore vision in a murine model of severe early-onset retinal degeneration. Intravitreal injection of an adeno-associated viral vector carrying the sequence for bReaChES downstream of the calcium calmodulin kinase IIα promoter resulted in sustained retinal expression of bReaChES. Retinal ganglion cells (RGCs) expressing bReaChES generated action potentials at light levels consistent with bright indoor lighting (from 13.6 log photons cm-2 s-1). They could also detect flicker at up to 50 Hz, which approaches the upper temporal limit of human photopic vision. Topological response maps of bReaChES-expressing RGCs suggest that optogenetically activated RGCs may demonstrate similar topographical responses to RGCs stimulated by photoreceptor activation. Furthermore, treated dystrophic mice displayed restored cortical neuronal activity in response to light and rescued behavioral responses to a looming stimulus that simulated an aerial predator. Finally, human surgical retinal explants exposed to the bReaChES treatment vector demonstrated transduction. Together, these findings suggest that intravitreal gene therapy to deliver bReaChES to the retina may restore vision in human retinal degeneration in vivo at ecologically relevant light levels with spectral and temporal response characteristics approaching those of normal human photopic vision.
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2
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Xi Z, Öztürk BE, Johnson ME, Turunç S, Stauffer WR, Byrne LC. Quantitative single-cell transcriptome-based ranking of engineered AAVs in human retinal explants. Mol Ther Methods Clin Dev 2022; 25:476-489. [PMID: 35615708 PMCID: PMC9118357 DOI: 10.1016/j.omtm.2022.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 04/26/2022] [Indexed: 11/07/2022]
Abstract
Gene therapy is a rapidly developing field, and adeno-associated viruses (AAVs) are a leading viral-vector candidate for therapeutic gene delivery. Newly engineered AAVs with improved abilities are now entering the clinic. It has proven challenging, however, to predict the translational potential of gene therapies developed in animal models due to cross-species differences. Human retinal explants are the only available model of fully developed human retinal tissue and are thus important for the validation of candidate AAV vectors. In this study, we evaluated 18 wild-type and engineered AAV capsids in human retinal explants using a recently developed single-cell RNA sequencing (RNA-seq) AAV engineering pipeline (scAAVengr). Human retinal explants retained the same major cell types as fresh retina, with similar expression of cell-specific markers except for a photoreceptor population with altered expression of photoreceptor-specific genes. The efficiency and tropism of AAVs in human explants were quantified with single-cell resolution. The top-performing serotypes, K91, K912, and 7m8, were further validated in non-human primate and human retinal explants. Together, this study provides detailed information about the transcriptome profiles of retinal explants and quantifies the infectivity of leading AAV serotypes in human retina, accelerating the translation of retinal gene therapies to the clinic.
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Affiliation(s)
- Zhouhuan Xi
- Department of Ophthalmology, University of Pittsburgh, PA, USA.,Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, Hunan, China
| | - Bilge E Öztürk
- Department of Ophthalmology, University of Pittsburgh, PA, USA
| | - Molly E Johnson
- Department of Ophthalmology, University of Pittsburgh, PA, USA
| | - Serhan Turunç
- Department of Ophthalmology, University of Pittsburgh, PA, USA
| | | | - Leah C Byrne
- Department of Ophthalmology, University of Pittsburgh, PA, USA.,Department of Neurobiology, University of Pittsburgh, PA, USA.,Department of Bioengineering, University of Pittsburgh, PA, USA
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3
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Wang JH, Lidgerwood GE, Daniszewski M, Hu ML, Roberts GE, Wong RCB, Hung SSC, McClements ME, Hewitt AW, Pébay A, Hickey DG, Edwards TL. AAV2-mediated gene therapy for Bietti crystalline dystrophy provides functional CYP4V2 in multiple relevant cell models. Sci Rep 2022; 12:9525. [PMID: 35680963 PMCID: PMC9184470 DOI: 10.1038/s41598-022-12210-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/06/2022] [Indexed: 12/23/2022] Open
Abstract
Bietti crystalline dystrophy (BCD) is an inherited retinal disease (IRD) caused by mutations in the CYP4V2 gene. It is a relatively common cause of IRD in east Asia. A number of features of this disease make it highly amenable to gene supplementation therapy. This study aims to validate a series of essential precursor in vitro experiments prior to developing a clinical gene therapy for BCD. We demonstrated that HEK293, ARPE19, and patient induced pluripotent stem cell (iPSC)-derived RPE cells transduced with AAV2 vectors encoding codon optimization of CYP4V2 (AAV2.coCYP4V2) resulted in elevated protein expression levels of CYP4V2 compared to those transduced with AAV2 vectors encoding wild type CYP4V2 (AAV2.wtCYP4V2), as assessed by immunocytochemistry and western blot. Similarly, we observed significantly increased CYP4V2 enzyme activity in cells transduced with AAV2.coCYP4V2 compared to those transduced with AAV2.wtCYP4V2. We also showed CYP4V2 expression in human RPE/choroid explants transduced with AAV2.coCYP4V2 compared to those transduced with AAV2.wtCYP4V2. These preclinical data support the further development of a gene supplementation therapy for a currently untreatable blinding condition—BCD. Codon-optimized CYP4V2 transgene was superior to wild type in terms of protein expression and enzyme activity. Ex vivo culture of human RPE cells provided an effective approach to test AAV-mediated transgene delivery.
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Affiliation(s)
- Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia
| | - Grace E Lidgerwood
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia.,Department of Anatomy and Physiology, The University of Melbourne, Parkville, Australia
| | - Maciej Daniszewski
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, Australia
| | - Monica L Hu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia
| | - Georgina E Roberts
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia
| | - Raymond C B Wong
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia.,Ophthalmology, Department of Surgery, The University of Melbourne, East Melbourne, VIC, Australia.,Shenzhen Eye Hospital, Shenzhen University School of Medicine, Shenzhen, China
| | - Sandy S C Hung
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia.,Ophthalmology, Department of Surgery, The University of Melbourne, East Melbourne, VIC, Australia
| | - Michelle E McClements
- Department of Clinical Neurosciences, Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - Alex W Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia.,Ophthalmology, Department of Surgery, The University of Melbourne, East Melbourne, VIC, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Alice Pébay
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, Australia.,Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Doron G Hickey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia
| | - Thomas L Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Level 7, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia. .,Ophthalmology, Department of Surgery, The University of Melbourne, East Melbourne, VIC, Australia.
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4
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McClements ME, Steward H, Atkin W, Goode EA, Gándara C, Chichagova V, MacLaren RE. Tropism of AAV Vectors in Photoreceptor-Like Cells of Human iPSC-Derived Retinal Organoids. Transl Vis Sci Technol 2022; 11:3. [PMID: 35377942 PMCID: PMC8994202 DOI: 10.1167/tvst.11.4.3] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 03/07/2022] [Indexed: 01/04/2023] Open
Abstract
Purpose To expand the use of human retinal organoids from induced pluripotent stem cells (iPSCs) as an in vitro model of the retina for assessing gene therapy treatments, it is essential to establish efficient transduction. To date, targeted transduction of the photoreceptor-like cells of retinal organoids with adeno-associated virus (AAV) vectors has had varied degrees of success, which we have looked to improve in this study. Methods Retinal organoids were differentiated from iPSCs of healthy donors and transduced with reporter AAV containing a CAG.GFP, CAG.RFP, GRK1.GFP, or EFS.GFP transgene. Capsid variants assessed were AAV5, AAV2 7m8, AAV2 quad mutant, AAV2 Y444F, and AAV8 Y733F. At 27 days post-transduction, retinal organoids were assessed for reporter expression and viability. Results The short intron-less elongation factor 1 alpha (EFS) promoter provided minimal reporter expression, whereas vectors containing the CAG promoter enabled transduction in 1% to 37% of cells depending on the AAV serotype; the AAV2 quad mutant (average 19.4%) and AAV2 7m8 (16.4%) outperformed AAV5 (12%) and AAV8 Y733F (2.1%). Reporter expression from rhodopsin kinase (GRK1) promoter transgenes occurred in ∼5% of cells regardless of the serotype. Positive co-localization with recoverin-expressing cells was achieved from all GRK1 vectors and the CAG AAV2 quad mutant variant. Treatment with the AAV vectors did not influence retinal organoid viability. Conclusions Reliable transduction of the photoreceptor-like cells of retinal organoids can be readily achieved. When using a CAG-driven transgene, transduction of a broad range of cell types is observed, and GRK1 transgenes provide a more restricted expression profile locating to the outer layer of photoreceptor-like cells of retinal organoids. Translational Relevance This study expands the AAV capsid and transgene options for preclinical testing of gene therapy in iPSC-derived human retinal organoids.
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Affiliation(s)
- Michelle E. McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, and Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford, UK
| | | | | | | | | | | | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, and Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford, UK
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5
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Bucher K, Rodriguez-Bocanegra E, Fischer MD. Benefits and Shortcomings of Laboratory Model Systems in the Development of Genetic Therapies. Klin Monbl Augenheilkd 2022; 239:263-269. [PMID: 35316853 DOI: 10.1055/a-1757-9879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Gene therapeutic approaches promise treatment or even a cure of diseases that were previously untreatable. Retinal gene therapies tested in clinical trials comprise a wide range of different strategies, including gene supplementation therapies, in vivo gene editing, modulation of splicing mechanisms, or the suppression of gene expression. To guarantee efficient transfer of genetic material into the respective target cells while avoiding major adverse effects, the development of genetic therapies requires appropriate in vitro model systems that allow tests of efficacy and safety of the gene therapeutic approach. In this review, we introduce various in vitro models of different levels of complexity used in the development of genetic therapies and discuss their respective benefits and shortcomings using the example of adeno-associated virus-based retinal gene therapy.
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Affiliation(s)
- Kirsten Bucher
- University Eye Hospital, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany.,Institute for Ophthalmic Research, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany
| | | | - M Dominik Fischer
- University Eye Hospital, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany.,Institute for Ophthalmic Research, University Hospital Tübingen Clinic of Ophthalmology, Tubingen, Germany.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom of Great Britain and Northern Ireland.,Department of Clinical Neurosciences, University of Oxford Nuffield Laboratory of Ophthalmology, Oxford, United Kingdom of Great Britain and Northern Ireland
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6
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Too LK, Shen W, Mammo Z, Osaadon P, Gillies MC, Simunovic MP. SURGICAL RETINAL EXPLANTS AS A SOURCE OF RETINAL PROGENITOR CELLS. Retina 2021; 41:1986-1993. [PMID: 33560780 PMCID: PMC8384250 DOI: 10.1097/iae.0000000000003137] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE To describe the novel observation of spontaneously migrating retinal cells from living donor surgical retinal explants that express progenitor cell markers in the absence of exogenous growth factors. METHODS Surgical retinal explants were harvested from 5 consecutive patients undergoing 23 G pars plana vitrectomy for the management of rhegmatogenous detachment. During surgery, equatorial flap tears were trimmed with the vitreous cutter and aspirated. Excised tissue was then regurgitated into a syringe containing balanced salt solution and immediately transferred to tissue culture. Migrating cells subsequently underwent immunohistochemical staining and their characteristics were compared with those of a spontaneously immortalized Müller stem cell line. RESULTS Spontaneously migrating cells were observed from samples taken from all 5 patients from Day 2 to 10 after transfer to culture. These cells were found to express embryonic cell markers, including paired box 6 (Pax6), sex-determining region Y-box 2 (Sox-2), nestin, cone-rod homeobox, and cyclin-dependent kinase inhibitor 1B (p27Kip1) as well as proteins consistent with early or retained differentiation down the Müller cell lineage, including glial fibrillary acidic protein and glutamine synthetase. CONCLUSION After injury, the human equatorial retina is capable of spontaneously producing cells that demonstrate migration and that express progenitor cell markers. In addition, these cells express proteins consistent with Müller cell lineage. These initial observations support the assertion that the human retina may possess the potential for regeneration and that surgical retinal explants could also act as a ready source of retinal progenitor cells.
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Affiliation(s)
- Lay Khoon Too
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia; and
| | - Weiyong Shen
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia; and
| | - Zaid Mammo
- Sydney Eye Hospital, Sydney, New South Wales
| | | | - Mark C. Gillies
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia; and
- Sydney Eye Hospital, Sydney, New South Wales
| | - Matthew P. Simunovic
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia; and
- Sydney Eye Hospital, Sydney, New South Wales
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7
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Hu ML, Edwards TL, O'Hare F, Hickey DG, Wang JH, Liu Z, Ayton LN. Gene therapy for inherited retinal diseases: progress and possibilities. Clin Exp Optom 2021; 104:444-454. [PMID: 33689657 DOI: 10.1080/08164622.2021.1880863] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal diseases (IRDs) comprise a heterogeneous group of genetic disorders affecting the retina. Caused by mutations in over 300 genes, IRDs result in visual impairment due to dysfunction and degeneration of photoreceptors, retinal pigment epithelium, or the choroid. Important photoreceptor IRDs include retinitis pigmentosa and Leber congenital amaurosis. Macular dystrophies include Stargardt and Best disease. Currently, IRDs are largely incurable but the landscape of treatment options is rapidly changing for these diseases which, untreated, result in severe visual impairment and blindness.Advances in DNA delivery to the retina and improved genetic diagnosis of IRDs have led to a new era of research into gene therapy for these vision-threatening disorders. Gene therapy is a compelling approach due to the monogenic nature of most IRDs, with the retina being a favourable target for administering genetic vectors due to its immunoprivileged environment, direct visibility, and multiple methods to assess sensitivity and function. Generally, retinal gene therapy involves a subretinal or intravitreal injection of a viral vector, which infects target cells to deliver a therapeutic gene, or transgene. A gene augmentation strategy introduces a functioning copy of a gene to restore expression of a mutated gene, whereas a gene-editing strategy aims to directly edit and correct the mutation. Common delivery vectors include adeno-associated virus (AAV) and lentivirus.Voretigene neparvovec-rzyl (Luxturna) became the first FDA-approved direct gene therapy in December 2017, and the Australian TGA followed suit in August 2020. More are projected to follow, with clinical trials underway for many other IRDs.This review provides an overview of gene therapy for IRDs, including current progress and challenges. A companion article in this issue details target patient populations for IRD gene therapy, and how optometrists can assist in assessing individuals who may be eligible for current and future therapies.
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Affiliation(s)
- Monica L Hu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Thomas L Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia
| | - Fleur O'Hare
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia.,Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia
| | - Doron G Hickey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Zhengyang Liu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Lauren N Ayton
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia.,Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia
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8
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McClements ME, Staurenghi F, MacLaren RE, Cehajic-Kapetanovic J. Optogenetic Gene Therapy for the Degenerate Retina: Recent Advances. Front Neurosci 2020; 14:570909. [PMID: 33262683 PMCID: PMC7686539 DOI: 10.3389/fnins.2020.570909] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/23/2020] [Indexed: 12/18/2022] Open
Abstract
The degeneration of light-detecting rod and cone photoreceptors in the human retina leads to severe visual impairment and ultimately legal blindness in millions of people worldwide. Multiple therapeutic options at different stages of degeneration are being explored but the majority of ongoing clinical trials involve adeno-associated viral (AAV) vector-based gene supplementation strategies for select forms of inherited retinal disease. Over 300 genes are associated with inherited retinal degenerations and only a small proportion of these will be suitable for gene replacement therapy. However, while the origins of disease may vary, there are considerable similarities in the physiological changes that occur in the retina. When early therapeutic intervention is not possible and patients suffer loss of photoreceptor cells but maintain remaining layers of cells in the neural retina, there is an opportunity for a universal gene therapy approach that can be applied regardless of the genetic origin of disease. Optogenetic therapy offers such a strategy by aiming to restore vision though the provision of light-sensitive molecules to surviving cell types of the retina that enable light perception through the residual neurons. Here we review the recent progress in attempts to restore visual function to the degenerate retina using optogenetic therapy. We focus on multiple pre-clinical models used in optogenetic strategies, discuss their strengths and limitations, and highlight considerations including vector and transgene designs that have advanced the field into two ongoing clinical trials.
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Affiliation(s)
- Michelle E. McClements
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Federica Staurenghi
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Robert E. MacLaren
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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9
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Wang D, Tai PWL, Gao G. Adeno-associated virus vector as a platform for gene therapy delivery. Nat Rev Drug Discov 2019; 18:358-378. [PMID: 30710128 DOI: 10.1038/s41573-019-0012-9] [Citation(s) in RCA: 1222] [Impact Index Per Article: 244.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adeno-associated virus (AAV) vectors are the leading platform for gene delivery for the treatment of a variety of human diseases. Recent advances in developing clinically desirable AAV capsids, optimizing genome designs and harnessing revolutionary biotechnologies have contributed substantially to the growth of the gene therapy field. Preclinical and clinical successes in AAV-mediated gene replacement, gene silencing and gene editing have helped AAV gain popularity as the ideal therapeutic vector, with two AAV-based therapeutics gaining regulatory approval in Europe or the United States. Continued study of AAV biology and increased understanding of the associated therapeutic challenges and limitations will build the foundation for future clinical success.
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Affiliation(s)
- Dan Wang
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.,Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA.,Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Phillip W L Tai
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.,Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA.,Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA. .,Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA. .,Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
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10
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Murali A, Ramlogan-Steel CA, Steel JC, Layton CJ. Characterisation and validation of the 8-fold quadrant dissected human retinal explant culture model for pre-clinical toxicology investigation. Toxicol In Vitro 2019; 63:104716. [PMID: 31706033 DOI: 10.1016/j.tiv.2019.104716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/13/2019] [Accepted: 11/04/2019] [Indexed: 11/30/2022]
Abstract
One of the major challenges in studying ocular toxicology is a lack of clinically-relevant retinal experimental models. In this study we describe the use of an in vitro human retinal explant strategy to generate a reproducible experimental model with utility in neuro-toxicity retinal studies. A retinal dissection strategy, referred to as the 8 fold quadrant dissection, was developed by dissecting human donor retinas into 4 fragments through the fovea in order to obtain 8 experimentally reproducible retinal explants from a single donor. This quadrant dissection gave rise to equivalent proportions of CD73+ photoreceptors and CD90+ ganglion cells in 8 fragments from a single donor and this remained stable for up to 3 days in culture. Major retinal cell types continued to be observed after 8 weeks in culture, despite breakdown of the retinal layers, suggesting the potential to use this model in long-term studies where observation of individual cell types is possible. The utility of this system was examined in a proof of principle neuro-toxicology study. We showed reproducible induction of toxicity in photoreceptors and retinal ganglion cells by glutamate, cobalt chloride and hydrogen peroxide insults, and observed the therapeutic positive effects of the administration of memantine, formononetin and trolox. The quadrant dissected human retinal explants have the potential to be used in toxicology studies in human ocular diseases.
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Affiliation(s)
- Aparna Murali
- LVF Ophthalmology Research Centre, Translational Research Institute, Woolloongabba, QLD, Australia; Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Australia
| | - Charmaine A Ramlogan-Steel
- LVF Ophthalmology Research Centre, Translational Research Institute, Woolloongabba, QLD, Australia; Central Queensland University, School of Health, Medical and Applied Science, Rockhampton, QLD, Australia
| | - Jason C Steel
- Central Queensland University, School of Health, Medical and Applied Science, Rockhampton, QLD, Australia.
| | - Christopher J Layton
- LVF Ophthalmology Research Centre, Translational Research Institute, Woolloongabba, QLD, Australia; Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Australia.
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11
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Alarautalahti V, Ragauskas S, Hakkarainen JJ, Uusitalo-Järvinen H, Uusitalo H, Hyttinen J, Kalesnykas G, Nymark S. Viability of Mouse Retinal Explant Cultures Assessed by Preservation of Functionality and Morphology. Invest Ophthalmol Vis Sci 2019; 60:1914-1927. [PMID: 31042799 DOI: 10.1167/iovs.18-25156] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Retinal explant cultures provide simplified systems where the functions of the retina and the effects of ocular therapies can be studied in an isolated environment. The purpose of this study was to provide insight into long-term preservation of retinal tissue in culture conditions, enable a deeper understanding of the interdependence of retinal morphology and function, and ensure the reliability of the explant technique for prolonged experiments. Methods Retinal explants from adult mice were cultured as organotypic culture at the air-medium interface for 14 days in vitro (DIV). Retinal functionality was assessed by multielectrode array technique and morphology by immunohistochemical methods at several time points during culture. Results Retinal explants retained viability for 14 DIV, although with diminishing neuronal activity, progressing neuronal loss, and increasing reactive gliosis. We recorded spontaneous retinal ganglion cell (RGC) activity up to 14 DIV with temporally changing distribution of RGC firing rates. Light responsiveness was measurable from RGCs for 7 DIV and from photoreceptors for 2 DIV. Apoptotic cells were detected beginning at 3 DIV with their density peaking at 7 DIV. The number of RGCs gradually decreased by 70% during 14 DIV. The change was accompanied by the loss of RGC functionality, resulting in 84% loss of electrically active RGCs. Conclusions Retinal explants provide a valuable tool for studies of retinal functions and development of ocular therapies. However, critical for long-term use, retinal functionality was lost before structural loss, emphasizing a need for both functional and morphologic readouts to determine the overall state of the cultured retina.
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Affiliation(s)
- Virpi Alarautalahti
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | | | | | - Hannele Uusitalo-Järvinen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Tays Eye Centre, Tampere University Hospital, Tampere, Finland
| | - Hannu Uusitalo
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Tays Eye Centre, Tampere University Hospital, Tampere, Finland
| | - Jari Hyttinen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | | | - Soile Nymark
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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12
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Devoldere J, Peynshaert K, Dewitte H, Vanhove C, De Groef L, Moons L, Özcan SY, Dalkara D, De Smedt SC, Remaut K. Non-viral delivery of chemically modified mRNA to the retina: Subretinal versus intravitreal administration. J Control Release 2019; 307:315-330. [PMID: 31265881 DOI: 10.1016/j.jconrel.2019.06.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/20/2019] [Accepted: 06/29/2019] [Indexed: 12/20/2022]
Abstract
mRNA therapeutics have recently experienced a new wave of interest, mainly due to the discovery that chemical modifications to mRNA's molecular structure could drastically reduce its inherent immunogenicity and perceived instability. On this basis, we aimed to explore the potential of chemically stabilized mRNA for ocular applications. More specifically, we investigated the behavior of mRNA-loaded lipid-based carriers in human retinal cells (in vitro), in bovine retinal explants (ex vivo) and in mouse retinas (in vivo). We demonstrate a clear superiority of mRNA over pDNA to induce protein expression in different retinal cell types, which was further enhanced by chemical modification of the mRNA, providing up to ~1800-fold higher reporter gene expression compared to pDNA. Moreover, transgene expression could be detected for at least 20 days after a single administration of chemically modified mRNA in vitro. We furthermore determined the localization and extent of mRNA expression depending on the administration route. After subretinal (SR) administration, mRNA expression was observed in vivo and ex vivo. By contrast, intravitreal (IVT) administration resulted in limited expression in vivo. Using ex vivo bovine explants with an intact vitreoretinal (VR) interface we could attribute this to the inner limiting membrane (ILM), which presents a large barrier for non-viral delivery of mRNA, trapping mRNA complexes at the vitreal side. When the vitreous was removed, which compromises the ILM, mRNA expression was apparent and seemed to colocalize with Müller cells or photoreceptors after respectively IVT or SR administration. Taken together, this study represents a first step towards mRNA-mediated therapy for retinal diseases.
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Affiliation(s)
- Joke Devoldere
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Karen Peynshaert
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Heleen Dewitte
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Laboratory for Molecular and Cellular Therapy, Department of Biomedical Sciences, Medical School of the Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1050 Jette, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Christian Vanhove
- Department of Respiratory Medicine, Ghent University, 9000 Ghent, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Sinem Yilmaz Özcan
- Neurological Sciences and Psychiatry Institute; Hacettepe University, Ankara, Turkey
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France
| | - Stefaan C De Smedt
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Katrien Remaut
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
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13
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Chandler LC, Barnard AR, Caddy SL, Patrício MI, McClements ME, Fu H, Rada C, MacLaren RE, Xue K. Enhancement of Adeno-Associated Virus-Mediated Gene Therapy Using Hydroxychloroquine in Murine and Human Tissues. Mol Ther Methods Clin Dev 2019; 14:77-89. [PMID: 31309129 PMCID: PMC6606965 DOI: 10.1016/j.omtm.2019.05.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/20/2019] [Indexed: 12/20/2022]
Abstract
The therapeutic effects of gene therapy using adeno-associated virus (AAV) vectors are dependent on the efficacy of viral transduction. Currently, we have reached the safe limits of AAV vector dose, beyond which damaging inflammatory responses are seen. To improve the efficacy of AAV transduction, we treated mouse embryonic fibroblasts, primate retinal pigment epithelial cells, and human retinal explants with hydroxychloroquine (HCQ) 1 h prior to transduction with an AAV2 vector encoding GFP driven by a ubiquitous CAG promoter. This led to a consistent increase in GFP expression, up to 3-fold, compared with vector alone. Comparing subretinal injections of AAV2.CAG.GFP vector alone versus co-injection with 18.75 μM HCQ in paired eyes in mice, mean GFP expression was 4.6-fold higher in retinae co-treated with HCQ without retinal toxicity. A comparative 5.9-fold effect was seen with an AAV8(Y733F).GRK1.GFP vector containing the photoreceptor-specific rhodopsin kinase promoter. While the mechanism of action remains to be fully elucidated, our data suggest that a single pulse of adjunctive HCQ could safely improve AAV transduction in vivo, thus providing a novel strategy for enhancing the clinical effects of gene therapy.
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Affiliation(s)
- Laurel C. Chandler
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford OX3 9DU, UK
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford OX3 9DU, UK
| | - Sarah L. Caddy
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Maria I. Patrício
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford OX3 9DU, UK
| | - Michelle E. McClements
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Howell Fu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Cristina Rada
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford OX3 9DU, UK
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, NIHR Biomedical Research Centre, Oxford OX3 9DU, UK
- Corresponding author: Kanmin Xue, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK.
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14
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Murali A, Ramlogan-Steel CA, Andrzejewski S, Steel JC, Layton CJ. Retinal explant culture: A platform to investigate human neuro-retina. Clin Exp Ophthalmol 2018; 47:274-285. [PMID: 30378239 DOI: 10.1111/ceo.13434] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/01/2018] [Accepted: 10/22/2018] [Indexed: 01/09/2023]
Abstract
The retina is the tissue responsible for light detection, in which retinal neurons convert light energy into electrical signals to be transported towards the visual cortex. Damage of retinal neurons leads to neuronal cell death and retinal pathologies, compromising visual acuity and eventually leading to irreversible blindness. Models of retinal neurodegeneration include 2D systems like cell lines, disassociated cultures and co-cultures, and 3D models like organoids, organotypic retinal cultures and animal models. Of these, ex vivo human retinal cultures are arguably the most suitable models for translational research as they retain complex inter-cellular interactions of the retina and precisely mimic in-situ responses. In this review, we summarize the distinguishing features of the human retina which are important to preserve in experimental culture, the historical development of human retinal culture systems, the factors affecting ex vivo human retinal culture and the applications and challenges associated with current methods of human retinal explant culture.
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Affiliation(s)
- Aparna Murali
- LVF Ophthalmology Research Centre, Translational Research Institute, Woolloongabba, Queensland, Australia.,Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Charmaine A Ramlogan-Steel
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia.,School of Health, Medical and Applied Sciences, CQUniversity, North Rockhampton, Queensland, Australia
| | - Slawomir Andrzejewski
- LVF Ophthalmology Research Centre, Translational Research Institute, Woolloongabba, Queensland, Australia.,Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Jason C Steel
- School of Health, Medical and Applied Sciences, CQUniversity, North Rockhampton, Queensland, Australia
| | - Christopher J Layton
- LVF Ophthalmology Research Centre, Translational Research Institute, Woolloongabba, Queensland, Australia.,Faculty of Medicine, The University of Queensland, Greenslopes Hospital, Brisbane, Queensland, Australia
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15
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Haderspeck JC, Chuchuy J, Kustermann S, Liebau S, Loskill P. Organ-on-a-chip technologies that can transform ophthalmic drug discovery and disease modeling. Expert Opin Drug Discov 2018; 14:47-57. [DOI: 10.1080/17460441.2019.1551873] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jasmin C. Haderspeck
- Institute of Neuroanatomy & Developmental Biology (INDB), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Johanna Chuchuy
- Department of Women’s Health, Research Institute for Women’s Health, Eberhard Karls University Tübingen, Tübingen, Germany
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
| | - Stefan Kustermann
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Stefan Liebau
- Institute of Neuroanatomy & Developmental Biology (INDB), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Peter Loskill
- Department of Women’s Health, Research Institute for Women’s Health, Eberhard Karls University Tübingen, Tübingen, Germany
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
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16
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Gonzalez-Cordero A, Goh D, Kruczek K, Naeem A, Fernando M, Kleine Holthaus SM, Takaaki M, Blackford SJI, Kloc M, Agundez L, Sampson RD, Borooah S, Ovando-Roche P, Mehat MS, West EL, Smith AJ, Pearson RA, Ali RR. Assessment of AAV Vector Tropisms for Mouse and Human Pluripotent Stem Cell-Derived RPE and Photoreceptor Cells. Hum Gene Ther 2018; 29:1124-1139. [PMID: 29580100 DOI: 10.1089/hum.2018.027] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Adeno-associated viral vectors are showing great promise as gene therapy vectors for a wide range of retinal disorders. To date, evaluation of therapeutic approaches has depended almost exclusively on the use of animal models. With recent advances in human stem cell technology, stem cell-derived retina now offers the possibility to assess efficacy in human organoids in vitro. Here we test six adeno-associated virus (AAV) serotypes [AAV2/2, AAV2/9, AAV2/8, AAV2/8T(Y733F), AAV2/5, and ShH10] to determine their efficiency in transducing mouse and human pluripotent stem cell-derived retinal pigment epithelium (RPE) and photoreceptor cells in vitro. All the serotypes tested were capable of transducing RPE and photoreceptor cells in vitro. AAV ShH10 and AAV2/5 are the most efficient vectors at transducing both mouse and human RPE, while AAV2/8 and ShH10 achieved similarly robust transduction of human embryonic stem cell-derived cone photoreceptors. Furthermore, we show that human embryonic stem cell-derived photoreceptors can be used to establish promoter specificity in human cells in vitro. The results of this study will aid capsid selection and vector design for preclinical evaluation of gene therapy approaches, such as gene editing, that require the use of human cells and tissues.
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Affiliation(s)
- Anai Gonzalez-Cordero
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Debbie Goh
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Kamil Kruczek
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Arifa Naeem
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Milan Fernando
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Sophia-Martha Kleine Holthaus
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom .,2 MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom, United Kingdom
| | - Matsuki Takaaki
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Samuel J I Blackford
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Magdalena Kloc
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Leticia Agundez
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Robert D Sampson
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Shyamanga Borooah
- 3 Centre for Clinical Brain Sciences, University of Edinburgh , Edinburgh, United Kingdom
| | - Patrick Ovando-Roche
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Manjit S Mehat
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Emma L West
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Alexander J Smith
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Rachael A Pearson
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
| | - Robin R Ali
- 1 Department of Genetics, Institute of Ophthalmology, University College London, London, United Kingdom, United Kingdom
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