scholarly journals Development of a Bispecific Antibody-Based Platform for Retargeting of Capsid Modified AAV Vectors

2021 ◽  
Vol 22 (15) ◽  
pp. 8355
Author(s):  
Juliane Kuklik ◽  
Stefan Michelfelder ◽  
Felix Schiele ◽  
Sebastian Kreuz ◽  
Thorsten Lamla ◽  
...  
Keyword(s):  
Bispecific Antibody ◽  
Tumor Stroma ◽  
Cell Types ◽  
Limiting Factor ◽  
Adeno Associated Virus ◽  
Gene Therapies ◽  
Programmed Death ◽  
Distinct Disease ◽  
Activated Fibroblasts ◽  
Surface Loops

A major limiting factor for systemically delivered gene therapies is the lack of novel tissue specific AAV (Adeno-associated virus) derived vectors. Bispecific antibodies can be used to redirect AAVs to specific target receptors. Here, we demonstrate that the insertion of a short linear epitope “2E3” derived from human proprotein-convertase subtilisin/kexin type 9 (PCSK9) into different surface loops of the VP capsid proteins can be used for AAV de-targeting from its natural receptor(s), combined with a bispecific antibody-mediated retargeting. We chose to target a set of distinct disease relevant membrane proteins—fibroblast activation protein (FAP), which is upregulated on activated fibroblasts within the tumor stroma and in fibrotic tissues, as well as programmed death-ligand 1 (PD-L1), which is strongly upregulated in many cancers. Upon incubation with a bispecific antibody recognizing the 2E3 epitope and FAP or PD-L1, the bispecific antibody/rAAV complex was able to selectively transduce receptor positive cells. In summary, we developed a novel, rationally designed vector retargeting platform that can target AAVs to a new set of cellular receptors in a modular fashion. This versatile platform may serve as a valuable tool to investigate the role of disease relevant cell types and basis for novel gene therapy approaches.

scholarly journals Quantitative single-cell transcriptome-based ranking of engineered AAVs in human retinal explants

2021 ◽  
Author(s):  
Zhouhuan Xi ◽  
Bilge E. Ozturk ◽  
Molly E. Johnson ◽  
Leah C. Byrne
Keyword(s):  
Single Cell ◽  
Viral Vector ◽  
Cell Types ◽  
Adeno Associated Virus ◽  
Altered Expression ◽  
Gene Therapies ◽  
Retinal Tissue ◽  
Retinal Explants ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

Gene therapy is a rapidly developing field, and adeno-associated virus (AAV) is 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 wildtype and engineered AAV capsids in human retinal explants using a recently developed single-cell 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 cone population with altered expression of cone-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.

scholarly journals Adenine Base Editing in vivo with a Single Adeno-Associated Virus Vector

2021 ◽  
Author(s):  
Han Zhang ◽  
Nathan Bamidele ◽  
Pengpeng Liu ◽  
Ogooluwa Ojelabi ◽  
Xin D. Gao ◽  
...  
Keyword(s):  
Genetic Diseases ◽  
Cell Types ◽  
Vector System ◽  
Adeno Associated Virus ◽  
Base Editing ◽  
Guide Rna ◽  
Gene Therapies ◽  
Compact Size ◽  
Adenine Base

Base editors (BEs) have opened new avenues for the treatment of genetic diseases. However, advances in delivery approaches are needed to enable disease targeting of a broad range of tissues and cell types. Adeno-associated virus (AAV) vectors remain one of the most promising delivery vehicles for gene therapies. Currently, most BE/guide combinations and their promoters exceed the packaging limit (~5 kb) of AAVs. Dual-AAV delivery strategies often require high viral doses that impose safety concerns. In this study, we engineered an adenine base editor using a compact Cas9 from Neisseria meningitidis (Nme2Cas9). Compared to the well-characterized Streptococcus pyogenes Cas9-containing ABEs, Nme2-ABE possesses a distinct PAM (N4CC) and editing window, exhibits fewer off-target effects, and can efficiently install therapeutically relevant mutations in both human and mouse genomes. Importantly, we showed that in vivo delivery of Nme2-ABE and its guide RNA by a single-AAV vector can revert the disease mutation and phenotype in an adult mouse model of tyrosinemia. We anticipate that Nme2-ABE, by virtue of its compact size and broad targeting range, will enable a range of therapeutic applications with improved safety and efficacy due in part to packaging in a single-vector system.

scholarly journals scAAVengr: Single-cell transcriptome-based quantification of engineered AAVs in non-human primate retina

2020 ◽  
Author(s):  
Bilge E. Öztürk ◽  
Molly E. Johnson ◽  
Michael Kleyman ◽  
Serhan Turunç ◽  
Jing He ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Cell Types ◽  
Adeno Associated Virus ◽  
Gene Therapies ◽  
Naturally Occurring ◽  
Cell Transcriptome ◽  
Large Animals ◽  
Single Cell Transcriptome ◽  
Human Primate

AbstractAdeno-associated virus (AAV)-mediated gene therapies are rapidly advancing to the clinic, and AAV engineering has resulted in vectors with increased ability to deliver therapeutic genes. Although the choice of vector is critical, quantitative comparison of AAVs, especially in large animals, remains challenging. Here, we developed an efficient single-cell AAV engineering pipeline (scAAVengr) to quantify efficiency of AAV-mediated gene expression across all cell types. scAAVengr allows for definitive, head-to-head comparison of vectors in the same animal. To demonstrate proof-of-concept for the scAAVengr workflow, we quantified – with cell-type resolution – the abilities of naturally occurring and newly engineered AAVs to mediate gene expression in primate retina following intravitreal injection. A top performing variant, K912, was used to deliver SaCas9 and edit the rhodopsin gene in macaque retina, resulting in editing efficiency similar to infection rates detected by the scAAVengr workflow. These results validate scAAVengr as a powerful method for development of AAV vectors.

scholarly journals scAAVengr, a transcriptome-based pipeline for quantitative ranking of engineered AAVs with single-cell resolution

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Bilge E Öztürk ◽  
Molly E Johnson ◽  
Michael Kleyman ◽  
Serhan Turunç ◽  
Jing He ◽  
...  
Keyword(s):  
Single Cell ◽  
Genetic Research ◽  
Cell Types ◽  
Infection Rates ◽  
Adeno Associated Virus ◽  
Systemic Injection ◽  
Gene Therapies ◽  
Naturally Occurring ◽  
Large Animals ◽  
Therapy Center

Background:Adeno-associated virus (AAV)-mediated gene therapies are rapidly advancing to the clinic, and AAV engineering has resulted in vectors with increased ability to deliver therapeutic genes. Although the choice of vector is critical, quantitative comparison of AAVs, especially in large animals, remains challenging. Methods:Here, we developed an efficient single-cell AAV engineering pipeline (scAAVengr) to simultaneously quantify and rank efficiency of competing AAV vectors across all cell types in the same animal. Results:To demonstrate proof-of-concept for the scAAVengr workflow, we quantified - with cell-type resolution - the abilities of naturally occurring and newly engineered AAVs to mediate gene expression in primate retina following intravitreal injection. A top performing variant identified using this pipeline, K912, was used to deliver SaCas9 and edit the rhodopsin gene in macaque retina, resulting in editing efficiency similar to infection rates detected by the scAAVengr workflow. scAAVengr was then used to identify top-performing AAV variants in mouse brain, heart and liver following systemic injection. Conclusions:These results validate scAAVengr as a powerful method for development of AAV vectors. Funding:This work was supported by funding from the Ford Foundation, NEI/NIH, Research to Prevent Blindness, Foundation Fighting Blindness, UPMC Immune Transplant and Therapy Center, and the Van Sloun fund for canine genetic research.

scholarly journals Transduction of gluconeogenic enzymes prolongs cone photoreceptor survival and function in models of retinitis pigmentosa

2019 ◽  
Author(s):  
Yashodhan Chinchore ◽  
Tedi Begaj ◽  
Christelle Guillermeir ◽  
Matthew L. Steinhauser ◽  
Claudio Punzo ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Genetic Defect ◽  
Metabolic Stress ◽  
Cell Types ◽  
Adeno Associated Virus ◽  
Gene Therapies ◽  
Degenerative Disorders ◽  
Medical Need ◽  
Hereditary Nature ◽  
And Function

AbstractThe hereditary nature of many retinal degenerative disorders makes them potentially amenable to corrective gene therapies. Numerous clinical trials are ongoing with the goal to rectify the genetic defect in the afflicted cell types. However, the personalized nature of these approaches excludes many patients for whom the underlying mutation is not mapped, or the number of affected individuals is too few to develop a commercially viable therapy (vide infra). Thus, a therapy that can delay visual impairment irrespective of the underlying genetic etiology can satisfy this unmet medical need. Here, we demonstrate the utility of such an approach in retinitis pigmentosa (RP) by promoting survival of cone photoreceptors by targeting metabolic stress. These cells are not primarily affected by the inherited mutation, but their non-autonomous demise leads to a decline in daylight vision, greatly reducing the quality of life. We designed adeno-associated virus (AAV) vectors that promote gluconeogenesis- a pathway found in the liver which produces glucose in response to hypoglycemia. Retinal transduction with these vectors resulted in improved cone survival and delayed a decline in visual acuity in three different RP mouse models. Because this approach extended visual function independent of the primary mutation, therapies emanating from this approach could be used as a treatment option for a genetically heterogenous cohort of patients.

scholarly journals Implications of hematopoietic stem cells heterogeneity for gene therapies

Gene Therapy ◽  
2021 ◽  
Author(s):  
Jeremy Epah ◽  
Richard Schäfer
Keyword(s):  
Immune Cell ◽  
Ex Vivo ◽  
Bone Marrow Failure ◽  
Cell Types ◽  
Blood Disorders ◽  
Hematopoietic Stem ◽  
Therapeutic Concept ◽  
Gene Therapies ◽  
Bone Marrow Failure Syndromes ◽  
Immunodeficiency Syndrome

AbstractHematopoietic stem cell transplantation (HSCT) is the therapeutic concept to cure the blood/immune system of patients suffering from malignancies, immunodeficiencies, red blood cell disorders, and inherited bone marrow failure syndromes. Yet, allogeneic HSCT bear considerable risks for the patient such as non-engraftment, or graft-versus host disease. Transplanting gene modified autologous HSCs is a promising approach not only for inherited blood/immune cell diseases, but also for the acquired immunodeficiency syndrome. However, there is emerging evidence for substantial heterogeneity of HSCs in situ as well as ex vivo that is also observed after HSCT. Thus, HSC gene modification concepts are suggested to consider that different blood disorders affect specific hematopoietic cell types. We will discuss the relevance of HSC heterogeneity for the development and manufacture of gene therapies and in exemplary diseases with a specific emphasis on the key target HSC types myeloid-biased, lymphoid-biased, and balanced HSCs.

scholarly journals Virus-Mediated Transduction of Murine Retina with Adeno-Associated Virus: Effects of Viral Capsid and Genome Size

2002 ◽  
Vol 76 (15) ◽  
pp. 7651-7660 ◽  
Author(s):  
Grace S. Yang ◽  
Michael Schmidt ◽  
Ziying Yan ◽  
Jonathan D. Lindbloom ◽  
Thomas C. Harding ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Photoreceptor Cells ◽  
Cell Types ◽  
Full Length ◽  
Specific Cell ◽  
Adeno Associated Virus ◽  
Gene Therapy Vectors ◽  
Retinal Degenerative Diseases ◽  
Or Gene ◽  
Half Length

ABSTRACT Gene therapy vectors based on adeno-associated viruses (AAVs) show promise for the treatment of retinal degenerative diseases. In prior work, subretinal injections of AAV2, AAV5, and AAV2 pseudotyped with AAV5 capsids (AAV2/5) showed variable retinal pigmented epithelium (RPE) and photoreceptor cell transduction, while AAV2/1 predominantly transduced the RPE. To more thoroughly compare the efficiencies of gene transfer of AAV2, AAV3, AAV5, and AAV6, we quantified, using stereological methods, the kinetics and efficiency of AAV transduction to mouse photoreceptor cells. We observed persistent photoreceptor and RPE transduction by AAV5 and AAV2 up to 31 weeks and found that AAV5 transduced a greater volume than AAV2. AAV5 containing full-length or half-length genomes and AAV2/5 transduced comparable numbers of photoreceptor cells with similar rates of onset of expression. Compared to AAV2, AAV5 transduced significantly greater numbers of photoreceptor cells at 5 and 15 weeks after surgery (greater than 1,000 times and up to 400 times more, respectively). Also, there were 30 times more genome copies in eyes injected with AAV2/5 than in eyes injected with AAV2. Comparing AAVs with half-length genomes, AAV5 transduced only four times more photoreceptor cells than AAV2 at 5 weeks and nearly equivalent numbers at 15 weeks. The enhancement of transduction was seen at the DNA level, with 50 times more viral genome copies in retinas injected with AAV having short genomes than in retinas injected with AAV containing full-length ones. Subretinal injection of AAV2/6 showed only RPE transduction at 5 and 15 weeks, while AAV2/3 did not transduce retinal cells. We conclude that varying genome length and AAV capsids may allow for improved expression and/or gene transfer to specific cell types in the retina.

scholarly journals Planet of the AAVs: The Spinal Cord Injury Episode

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 613
Author(s):  
Katerina Stepankova ◽  
Pavla Jendelova ◽  
Lucia Machova Urdzikova
Keyword(s):  
Spinal Cord ◽  
Gene Therapy ◽  
Spinal Cord Injury ◽  
Cell Types ◽  
Specific Cell ◽  
Adeno Associated Virus ◽  
Adequate Treatment ◽  
Cord Injury ◽  
The Central Nervous System ◽  
Transgene Delivery

The spinal cord injury (SCI) is a medical and life-disrupting condition with devastating consequences for the physical, social, and professional welfare of patients, and there is no adequate treatment for it. At the same time, gene therapy has been studied as a promising approach for the treatment of neurological and neurodegenerative disorders by delivering remedial genes to the central nervous system (CNS), of which the spinal cord is a part. For gene therapy, multiple vectors have been introduced, including integrating lentiviral vectors and non-integrating adeno-associated virus (AAV) vectors. AAV vectors are a promising system for transgene delivery into the CNS due to their safety profile as well as long-term gene expression. Gene therapy mediated by AAV vectors shows potential for treating SCI by delivering certain genetic information to specific cell types. This review has focused on a potential treatment of SCI by gene therapy using AAV vectors.

scholarly journals Evading the AAV Immune Response in Mucopolysaccharidoses

2020 ◽  
Vol 21 (10) ◽  
pp. 3433
Author(s):  
Matthew Piechnik ◽  
Kazuki Sawamoto ◽  
Hidenori Ohnishi ◽  
Norio Kawamoto ◽  
Yasuhiko Ago ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Immune Response ◽  
Humoral Immune Response ◽  
Transgene Expression ◽  
Evidence Based ◽  
Adeno Associated Virus ◽  
Gene Therapies ◽  
Humoral Immune ◽  
Significant Challenge ◽  
Racial Background

The humoral immune response elicited by adeno-associated virus (AAV)-mediated gene therapy for the treatment of mucopolysaccharidoses (MPS) poses a significant challenge to achieving therapeutic levels of transgene expression. Antibodies targeting the AAV capsid as well as the transgene product diminish the production of glycosaminoglycan (GAG)-degrading enzymes essential for the treatment of MPS. Patients who have antibodies against AAV capsid increase in number with age, serotype, and racial background and are excluded from the clinical trials at present. In addition, patients who have undergone AAV gene therapy are often excluded from the additional AAV gene therapy with the same serotype, since their acquired immune response (antibody) against AAV will limit further efficacy of treatment. Several methods are being developed to overcome this immune response, such as novel serotype design, antibody reduction by plasmapheresis and immunosuppression, and antibody evasion using empty capsids and enveloped AAV vectors. In this review, we examine the mechanisms of the anti-AAV humoral immune response and evaluate the strengths and weaknesses of current evasion strategies in order to provide an evidence-based recommendation on evading the immune response for future AAV-mediated gene therapies for MPS.

Sign in / Sign up

Export Citation Format

Share Document