scholarly journals Emerging Concepts in Vector Development for Glial Gene Therapy: Implications for Leukodystrophies

2021 ◽  
Vol 15 ◽  
Author(s):  
Georg von Jonquieres ◽  
Caroline D. Rae ◽  
Gary D. Housley
Keyword(s):  
Gene Therapy ◽  
Ex Vivo ◽  
Treatment Options ◽  
Neurological Dysfunction ◽  
Specific Expression ◽  
Hematopoietic Stem ◽  
Gene Therapies ◽  
Neurometabolic Disorders ◽  
Specific Expression Pattern

Central Nervous System (CNS) homeostasis and function rely on intercellular synchronization of metabolic pathways. Developmental and neurochemical imbalances arising from mutations are frequently associated with devastating and often intractable neurological dysfunction. In the absence of pharmacological treatment options, but with knowledge of the genetic cause underlying the pathophysiology, gene therapy holds promise for disease control. Consideration of leukodystrophies provide a case in point; we review cell type – specific expression pattern of the disease – causing genes and reflect on genetic and cellular treatment approaches including ex vivo hematopoietic stem cell gene therapies and in vivo approaches using adeno-associated virus (AAV) vectors. We link recent advances in vectorology to glial targeting directed towards gene therapies for specific leukodystrophies and related developmental or neurometabolic disorders affecting the CNS white matter and frame strategies for therapy development in future.

scholarly journals Gene therapy of hemoglobinopathies: progress and future challenges

2019 ◽  
Vol 28 (R1) ◽  
pp. R24-R30 ◽  
Author(s):  
Yasuhiro Ikawa ◽  
Annarita Miccio ◽  
Elisa Magrin ◽  
Janet L Kwiatkowski ◽  
Stefano Rivella ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Clinical Trials ◽  
Ex Vivo ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Specific Expression ◽  
Widespread Application ◽  
Hematopoietic Stem ◽  
Transfusion Requirements ◽  
Future Challenges

Abstract Recently, gene therapy clinical trials have been successfully applied to hemoglobinopathies, such as sickle cell disease (SCD) and β-thalassemia. Among the great discoveries that led to the design of genetic approaches to cure these disorders is the discovery of the β-globin locus control region and several associated transcription factors, which determine hemoglobin switching as well as high-level, erythroid-specific expression of genes at the ß-globin locus. Moreover, increasing evidence shows that lentiviral vectors are efficient tools to insert large DNA elements into nondividing hematopoietic stem cells, showing reassuring safe integration profiles. Alternatively, genome editing could restore expression of fetal hemoglobin or target specific mutations to restore expression of the wild-type β-globin gene. The most recent clinical trials for β-thalassemia and SCD are showing promising outcomes: patients were able to discontinue transfusions or had reduced transfusion requirements. However, toxic myeloablation and the high cost of current ex vivo hematopoietic stem cell gene therapy platforms represent a barrier to a widespread application of these approaches. In this review, we summarize these gene therapy strategies and ongoing clinical trials. Finally, we discuss possible strategies to improve outcomes, reduce myeloablative regimens and future challenges to reduce the cost of gene therapy platform.

Development of Megakaryocyte-Specific Lentiviral Vectors for Gene Therapy of Platelet Disorders.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 5143-5143
Author(s):  
Liesbeth De Waele ◽  
Kathleen Freson ◽  
Chantal Thys ◽  
Christel Van Geet ◽  
Désiré Collen ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Transgene Expression ◽  
Ex Vivo ◽  
Phosphoglycerate Kinase ◽  
Lentiviral Vectors ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Platelet Disorders

Abstract The prevalence of congenital platelet disorders has not been established but for some life-threatening bleeding disorders the current therapies are not adequate, justifying the development of alternative strategies as gene therapy. In the case of platelet dysfunction and thrombocytopenia as described for GATA1 deficiency, potentially lethal internal bleedings can occur. The objective of the study is to develop improved lentiviral vectors for megakaryocyte(MK)-specific long term gene expression by ex vivo transduction of hematopoietic stem cells (HSC) to ultimately use for congenital thrombopathies as GATA1 deficiency. Self-inactivating lentiviral vectors were constructed expressing GFP driven by the murine (m) or human (h) GPIIb promoter. These promoters contain multiple Ets and GATA binding sites directing MK-specificity. To evaluate the cell lineage-specificity and transgene expression potential of the vectors, murine Sca1+ and human CD34+ HSC were transduced in vitro with Lenti-hGPIIb-GFP and Lenti-mGPIIb-GFP vectors. After transduction the HSC were induced to differentiate in vitro along the MK and non-MK lineages. The mGPIIb and hGPIIb promoters drove GFP expression at overall higher levels (20% in murine cells and 25% in human cells) than the ubiquitous CMV (cytomegalovirus) or PGK (phosphoglycerate kinase) promoters, and this exclusively in the MK lineage. Interestingly, in both human and murine HSC the hGPIIb promoter with an extra RUNX and GATA binding site, was more potent in the MK lineage compared to the mGPIIb promoter. Since FLI1 and GATA1 are the main transcription factors regulating GPIIb expression, we tested the Lenti-hGPIIb-GFP construct in GATA1 deficient HSC and obtained comparable transduction efficiencies as for wild-type HSC. To assess the MK-specificity of the lentiviral vectors in vivo, we transplanted irradiated wild-type C57Bl/6 mice with Sca1+ HSC transduced with the Lenti-hGPIIb-GFP constructs. Six months after transplantation we could detect 6% GFP positive platelets without a GFP signal in other cell lineages. Conclusion: In vitro and in vivo MK-specific transgene expression driven by the hGPIIb and mGPIIb promoters could be obtained after ex vivo genetic engineering of HSC by improved lentiviral vectors. Studies are ongoing to study whether this approach can induce phenotypic correction of GATA1 deficient mice by transplantation of ex vivo Lenti-hGPIIb-GATA1 transduced HSC.

Gene therapy comes of age

Science ◽  
2018 ◽  
Vol 359 (6372) ◽  
pp. eaan4672 ◽  
Author(s):  
Cynthia E. Dunbar ◽  
Katherine A. High ◽  
J. Keith Joung ◽  
Donald B. Kohn ◽  
Keiya Ozawa ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Viral Vectors ◽  
The United States ◽  
Genetically Engineered ◽  
Drug Status ◽  
Hematopoietic Stem ◽  
Gene Therapies ◽  
Engineered T Cells ◽  
Near Future

After almost 30 years of promise tempered by setbacks, gene therapies are rapidly becoming a critical component of the therapeutic armamentarium for a variety of inherited and acquired human diseases. Gene therapies for inherited immune disorders, hemophilia, eye and neurodegenerative disorders, and lymphoid cancers recently progressed to approved drug status in the United States and Europe, or are anticipated to receive approval in the near future. In this Review, we discuss milestones in the development of gene therapies, focusing on direct in vivo administration of viral vectors and adoptive transfer of genetically engineered T cells or hematopoietic stem cells. We also discuss emerging genome editing technologies that should further advance the scope and efficacy of gene therapy approaches.

scholarly journals Thalassemia Gene Therapy By In Vivo Transduction of Mobilized Hematopoietic Stem Cells (HSCs) with an Integrating Hybrid Adenovirus Vector System

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2193-2193
Author(s):  
Afrodite Georgakopoulou ◽  
Hongjie Wang ◽  
Chrysi Kapsali ◽  
Nikoleta Psatha ◽  
Angeliki Koufali ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Hematological Parameters ◽  
Sleeping Beauty ◽  
Vector System ◽  
Good Tolerability ◽  
Hematopoietic Stem

Abstract To overcome the cost and complexity of current thalassemia ex vivogene therapy protocols, we developed a minimally invasive and readily translatable approach for in vivo HSC gene delivery which abrogates the need for HSC leukapheresis, CD34+ cell selection, ex vivo HSC culture, myeloablation and ultimately, transplantation. Our approach involves HSC mobilization with G-CSF/AMD3100 andintravenous injections of a hybrid vector system consisting ofa CD46-targeting, helper-dependent adenoviral vector and the hyperactive Sleeping Beauty transposase (SB100x) that mediates integration of thevector-encoded γ-globin and mgmtP140K genes. Pretreatment with glucocorticoids before virus injectionsis used to blockthe release of pro-inflammatory cytokines andimmunosuppression is applied in order to avoid responses against human g-globin- and MGMT protein-expressing cells. We tested our approach in a mouse model recapitulating the phenotypeof human β-thalassemia intermedia (Hbbth-3/hCD46++ mice). At week 8 post transduction, hCD46+/+/Hbbth-3 mice expressed HbF in 31.2±2.7% of circulating erythrocytes. Due to a significant drop in HbF expression by week 16 (11.9±3.0%), a 4-dose O6BG/BCNU treatment was administeredin order to in vivo select forgene corrected hematopoietic progenitors, thus recovering the HbF expression in76.0±5.7% of the circulating erythrocytes, by week 29 post in vivo transduction. With an average vector copy number of 1.4/cell, the human γ-globin to mouse α-globin expression was ~10% by HPLC and the human γ-globin to mouse β-globin mRNA ratio ~10%, by qRT-PCR. Hematological parameters (RBCs, Ht, Hb, MCV, RDW, Reticulocytes) at week 29 post in vivo transduction, were significantly improved over baseline or were indistinguishable from normal values, suggesting near to complete phenotypic correction. Treated mice showed significant reduction of spleen size, extramedullary erythropoiesis and parenchymal hemosiderosis. After secondary transplantation and without in vivo selection, more than 90% of donor-derived erythrocytes (CD46+) were g-globin-positive, up to 20 weeks post-transplant. Safety was demonstrated by the good tolerability of treatment, the absence of alterations in hematopoiesis, the normal colony-forming potential of bone marrow cells and the random integration pattern of our vector system. Overall, we present a simplified platform for gene therapy of thalassemia, which can serve as a cost-efficient and "portable" approach to make gene therapy accessible even to resource-poor regions where thalassemia major is endemic but only minimally complex strategies could be adopted. Disclosures No relevant conflicts of interest to declare.

scholarly journals Reactivation of γ-globin in adult β-YAC mice after ex vivo and in vivo hematopoietic stem cell genome editing

Blood ◽  
2018 ◽  
Vol 131 (26) ◽  
pp. 2915-2928 ◽  
Author(s):  
Chang Li ◽  
Nikoletta Psatha ◽  
Pavel Sova ◽  
Sucheol Gil ◽  
Hongjie Wang ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Stem Cell ◽  
Binding Site ◽  
Genome Editing ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Key Points ◽  
Cell Genome ◽  
Hsc Transplantation

Key Points CRISPR/Cas9-mediated disruption of a BCL11A binding site in HSCs of β-YAC mice results in the reactivation of γ-globin in erythrocytes. Our approach for in vivo HSC genome editing that does not require HSC transplantation and myeloablation should simplify HSC gene therapy.

scholarly journals Modeling human lymphoid precursor cell gene therapy in the SCID-hu mouse

Blood ◽  
1994 ◽  
Vol 84 (5) ◽  
pp. 1393-1398 ◽  
Author(s):  
RK Akkina ◽  
JD Rosenblatt ◽  
AG Campbell ◽  
IS Chen ◽  
JA Zack
Keyword(s):  
Gene Therapy ◽  
In Vivo Model ◽  
Hematopoietic Stem ◽  
Gene Therapies ◽  
Human Cd34 ◽  
Human T Lymphocyte ◽  
Thymocyte Differentiation ◽  
Immunodeficiency Syndrome

Abstract Gene therapy of human T-lymphocyte disorders, including acquired immunodeficiency syndrome (AIDS), would be greatly facilitated by the development of an in vivo system in which transduced human hematopoietic stem cells can be used to reconstitute the T-lymphoid compartment. Here we use the SCID-hu mouse as a recipient for human CD34+ hematopoietic progenitor cells transduced in vitro with a retroviral vector carrying the neomycin resistance gene (neoR). The transduced cells engraft and reconstitute the lymphoid compartments of the human thymus implant with as few as 5 x 10(4) CD34+ cells. The neoR gene was expressed at low levels in human thymocytes and there was no apparent effect on thymocyte differentiation as a result of vector transduction. Thus, this SCID-hu mouse system is the first in vivo model showing human thymopoiesis after transduction of exogenous vectors, and should allow preclinical testing of gene therapeutic reagents designed to function in human cells of the T-lymphoid lineage. Because human immunodeficiency virus type 1 infection induces depletion of human thymocytes in SCID-hu mice, this system may be particularly valuable in evaluating efficacy of gene therapies to combat AIDS.

scholarly journals Evolving AAV-delivered therapeutics towards ultimate cures

2021 ◽  
Author(s):  
Xiangjun He ◽  
Brian Anugerah Urip ◽  
Zhenjie Zhang ◽  
Chun Christopher Ngan ◽  
Bo Feng
Keyword(s):  
Gene Therapy ◽  
Gene Editing ◽  
Treatment Options ◽  
Genetic Diseases ◽  
The United States ◽  
European Medicines Agency ◽  
Gene Therapies ◽  
Therapeutic Modalities ◽  
United States Food

AbstractGene therapy has entered a new era after decades-long efforts, where the recombinant adeno-associated virus (AAV) has stood out as the most potent vector for in vivo gene transfer and demonstrated excellent efficacy and safety profiles in numerous preclinical and clinical studies. Since the first AAV-derived therapeutics Glybera was approved by the European Medicines Agency (EMA) in 2012, there is an increasing number of AAV-based gene augmentation therapies that have been developed and tested for treating incurable genetic diseases. In the subsequent years, the United States Food and Drug Administration (FDA) approved two additional AAV gene therapy products, Luxturna and Zolgensma, to be launched into the market. Recent breakthroughs in genome editing tools and the combined use with AAV vectors have introduced new therapeutic modalities using somatic gene editing strategies. The promising outcomes from preclinical studies have prompted the continuous evolution of AAV-delivered therapeutics and broadened the scope of treatment options for untreatable diseases. Here, we describe the clinical updates of AAV gene therapies and the latest development using AAV to deliver the CRISPR components as gene editing therapeutics. We also discuss the major challenges and safety concerns associated with AAV delivery and CRISPR therapeutics, and highlight the recent achievement and toxicity issues reported from clinical applications.

scholarly journals Clinical Trials for Gene Therapy in Lysosomal Diseases With CNS Involvement

2021 ◽  
Vol 8 ◽  
Author(s):  
Caroline Sevin ◽  
Kumaran Deiva
Keyword(s):  
Gene Therapy ◽  
Central Nervous System ◽  
Clinical Trials ◽  
Nervous System ◽  
Ex Vivo ◽  
Central Nervous System Involvement ◽  
Large Animal ◽  
Hematopoietic Stem ◽  
The Brain

There are over 70 known lysosomal storage disorders (LSDs), most caused by mutations in genes encoding lysosomal hydrolases. Central nervous system involvement is a hallmark of the majority of LSDs and, if present, generally determines the prognosis of the disease. Nonetheless, brain disease is currently poorly targeted by available therapies, including systemic enzyme replacement therapy, mostly (but not only) due to the presence of the blood–brain barrier that restricts the access of orally or parenterally administered large molecules into the brain. Thus, one of the greatest and most exciting challenges over coming years will be to succeed in developing effective therapies for the treatment of central nervous system manifestations in LSDs. Over recent years, gene therapy (GT) has emerged as a promising therapeutic strategy for a variety of inherited neurodegenerative diseases. In LSDs, the ability of genetically corrected cells to cross-correct adjacent lysosomal enzyme-deficient cells in the brain after gene transfer might enhance the diffusion of the recombinant enzyme, making this group of diseases a strong candidate for such an approach. Both in vivo (using the administration of recombinant adeno-associated viral vectors) and ex vivo (auto-transplantation of lentiviral vector-modified hematopoietic stem cells-HSCs) strategies are feasible. Promising results have been obtained in an ever-increasing number of preclinical studies in rodents and large animal models of LSDs, and these give great hope of GT successfully correcting neurological defects, once translated to clinical practice. We are now at the stage of treating patients, and various clinical trials are underway, to assess the safety and efficacy of in vivo and ex vivo GT in several neuropathic LSDs. In this review, we summarize different approaches being developed and review the current clinical trials related to neuropathic LSDs, their results (if any), and their limitations. We will also discuss the pitfalls and the remaining challenges.

Next-generation sequencing is now utilized to identify genetic abnormalities and develop gene therapy

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Gene Therapy ◽  
Gene Editing ◽  
Somatic Mutations ◽  
Ex Vivo ◽  
Nuclear Genome ◽  
Gene Therapies ◽  
Genetic Abnormalities ◽  
Targeted Gene Editing ◽  
Nuclear Genomes

The genomic size, complexity, heritability, and diversity of human primary genetic compartments vary. Although the nuclear genome's huge size ensures that hundreds of reported monogenic diseases appear in a range of conditions, germline abnormalities in the mitochondrial and nuclear genomes often generate developmental issues. Accumulation of somatic mutations in the nuclear genome causes cancer, and somatic mutations in mitochondria may contribute to aging. More broadly, the microbial metagenome develops largely after birth, and is marked throughout their lifetimes by much more diversity and diversity among individuals. Mitochondrial sequencing, clinical exome and full-genome sequencing, and 16S and unbiased microbiological sequencing have all become more widely available because of developments in DNA sequencing next-generation.These technologies discover genetic defects that can be addressed with gene therapy. Modern aided techniques of reproduction, such as mitochondrial replacement therapy and preimplantation diagnosis, may address complete genomic compartments in bulk, such as mitochondrial and nuclear genomes. Additive somatic cell gene therapies started with the invention of viral vectors to infect human somatic cells that could be cultured ex vivo, such as T cells, and rapidly advanced to in vivo applications employing viral pseudotypes with specific tissue tropisms. CRISPR/Cas9 and other targeted gene editing approaches that fix the specific causative mutation or gene at its endogenous locus have recently expanded the possibility for more refined ex vivo and in vivo gene therapies.DNA sequencing costs have decreased during the past two decades, hurrying to identify genetic diseases. Targeted gene editing progress has now enabled the synthesis and testing of specific therapeutic reagents to address direct and accessible genetic abnormalities, repeating these diagnostic accomplishments. Generalized methods for delivering customizable gene editing reagents to the cell type and genomic compartment of interest in the specific genetic disease of a patient are one of the major outstanding challenges to wide-spread gene therapy. Aside from direct genetic disease repair, recent methods for rapidly identifying synthetic genetic circuits capable of improving cellular function in diseases such as cancer and autoimmune hold the promise of future gene therapy in modified somatic cells.Genetic diseases are becoming more readily diagnosed in all human genetic compartments, and the next generation of gene therapy platforms targeting each compartment are preparing to give flexible, tailored curative medicines. The Mitochondrial genome, nuclear genome, and microbial metagenome are the three genetic compartments present in humans. Gene therapies for each of these compartments come into three categories: whole genome replacement or selection, non-focused insertion of new genetic information to compensate for genetic errors, and direct gene editing to correct causative genetic disorders. The mitochondrial and nuclear genomes are determined at conception, save for somatic mutations and the adaptive immune receptor repertoire, and remain stable throughout life.

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