Multiple obstacles to gene therapy in the brain

AbstractNeuwelt et al. have proposed gene-transfer experiments utilizing an animal model that offers many important advantages for investigating the feasibility of gene therapy in the human brain. A variety of tissues concerning the viral vector and mode of delivery of the corrective genes need to be resolved, however, before such therapy is scientifically supportable.

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Efficient and Selective Gene Transfer into Primary Human Brain Tumors by Using Single-Chain Antibody-Targeted Adenoviral Vectors with Native Tropism Abolished

Journal of Virology ◽

10.1128/jvi.76.6.2753-2762.2002 ◽

2002 ◽

Vol 76 (6) ◽

pp. 2753-2762 ◽

Cited By ~ 56

Author(s):

Victor W. van Beusechem ◽

Jacques Grill ◽

D. C. Jeroen Mastenbroek ◽

Thomas J. Wickham ◽

Peter W. Roelvink ◽

...

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Brain Tumors ◽

Human Brain ◽

Cancer Gene Therapy ◽

Adenoviral Vectors ◽

Receptor Expression ◽

Normal Brain ◽

Cancer Gene ◽

Single Chain

ABSTRACT The application of adenoviral vectors in cancer gene therapy is hampered by low receptor expression on tumor cells and high receptor expression on normal epithelial cells. Targeting adenoviral vectors toward tumor cells may improve cancer gene therapy procedures by providing augmented tumor transduction and decreased toxicity to normal tissues. Targeting requires both the complete abolition of native tropism and the addition of a new specific binding ligand onto the viral capsid. Here we accomplished this by using doubly ablated adenoviral vectors, lacking coxsackievirus-adenovirus receptor and αv integrin binding capacities, together with bispecific single-chain antibodies targeted toward human epidermal growth factor receptor (EGFR) or the epithelial cell adhesion molecule. These vectors efficiently and selectively targeted both alternative receptors on the surface of human cancer cells. Targeted doubly ablated adenoviral vectors were also very efficient and specific with primary human tumor specimens. With primary glioma cell cultures, EGFR targeting augmented the median gene transfer efficiency of doubly ablated adenoviral vectors 123-fold. Moreover, EGFR-targeted doubly ablated vectors were selective for human brain tumors versus the surrounding normal brain tissue. They transduced organotypic glioma and meningioma spheroids with efficiencies similar to those of native adenoviral vectors, while exhibiting greater-than-10-fold-reduced background levels on normal brain explants from the same patients. As a result, EGFR-targeted doubly ablated adenoviral vectors had a 5- to 38-fold-improved tumor-to-normal brain targeting index compared to native vectors. Hence, single-chain targeted doubly ablated adenoviral vectors are promising tools for cancer gene therapy. They should provide an improved therapeutic index with efficient tumor transduction and effective protection of normal tissue.

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Whole brain delivery of an instability-proneMecp2transgene improves behavioral and molecular pathological defects in mouse models of Rett syndrome

10.1101/798793 ◽

2019 ◽

Author(s):

Mirko Luoni ◽

Serena Giannelli ◽

Marzia Indrigo ◽

Antonio Niro ◽

Luca Massimino ◽

...

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Rett Syndrome ◽

Protein Translation ◽

Mutant Mice ◽

Severe Toxicity ◽

Male And Female ◽

Protein Levels ◽

Mecp2 Protein ◽

The Brain

AbstractRett syndrome (RTT) is an incurable neurodevelopmental disorder caused by mutations in the gene encoding for methyl-CpG binding-protein 2 (MeCP2). Gene therapy for this disease presents inherent hurdles sinceMECP2is expressed throughout the brain and its duplication leads to severe neurological conditions as well. However, the recent introduction of AAV-PHP.eB, an engineered capsid with an unprecedented efficiency in crossing the blood-brain barrier upon intravenous injection, has provided an invaluable vehicle for gene transfer in the mouse nervous system. Herein, we use AAV-PHP.eB to deliver an instability-proneMecp2(iMecp2) transgene cassette which, increasing RNA destabilization and inefficient protein translation of the viralMecp2transgene, limits supraphysiological Mecp2 protein levels in transduced neural tissues. Intravenous injections of the PHP.eB-iMecp2virus in symptomatic male and femaleMecp2mutant mice significantly ameliorated the disease progression with improved locomotor activity, coordination, lifespan and normalization of altered gene expression and mTOR signaling. Remarkably, PHP.eB-iMecp2administration did not result in severe toxicity effects either in femaleMecp2mutant or in wild-type animals. In contrast, we observed a strong immune response to the transgene in treated maleMecp2mutant mice that was overcome by immunosuppression. Overall, PHP.eB-mediated delivery of theiMecp2cassette provided widespread and efficient gene transfer maintaining physiological Mecp2 protein levels in the brain. This combination defines a novel viral system with significant therapeutic efficacy and increased safety which can contribute to overcome the hurdles that are delaying clinical applications of gene therapy for RTT.One Sentence SummaryGlobal brain transduction of the instability-proneMecp2transgene by systemic AAV-PHP.eB administration is both safe and effective in protecting male and femaleMecp2mutant mice from the RTT disease phenotype.

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Nonviral Gene Therapy for Cancer: A Review

Diseases ◽

10.3390/diseases6030057 ◽

2018 ◽

Vol 6 (3) ◽

pp. 57 ◽

Cited By ~ 16

Author(s):

Chiaki Hidai ◽

Hisataka Kitano

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Viral Vectors ◽

Viral Vector ◽

Transfer Efficiency ◽

Nonviral Vectors ◽

Apparent Lack ◽

Gene Transfer Efficiency ◽

Relative Safety

Although the development of effective viral vectors put gene therapy on the road to commercialization, nonviral vectors show promise for practical use because of their relative safety and lower cost. A significant barrier to the use of nonviral vectors, however, is that they have not yet proven effective. This apparent lack of interest can be attributed to the problem of the low gene transfer efficiency associated with nonviral vectors. The efficiency of gene transfer via nonviral vectors has been reported to be 1/10th to 1/1000th that of viral vectors. Despite the fact that new gene transfer methods and nonviral vectors have been developed, no significant improvements in gene transfer efficiency have been achieved. Nevertheless, some notable progress has been made. In this review, we discuss studies that report good results using nonviral vectors in vivo in animal models, with a particular focus on studies aimed at in vivo gene therapy to treat cancer, as this disease has attracted the interest of researchers developing nonviral vectors. We describe the conditions in which nonviral vectors work more efficiently for gene therapy and discuss how the goals might differ for nonviral versus viral vector development and use.

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Immune Modulation by IL-10 Gene Transfer via Viral Vector and Plasmid DNA: Implication for Gene Therapy

Cellular Immunology ◽

10.1006/cimm.1999.1500 ◽

1999 ◽

Vol 194 (2) ◽

pp. 194-204 ◽

Cited By ~ 20

Author(s):

Sangjun Chun ◽

Massoud Daheshia ◽

Sujin Lee ◽

Barry T. Rouse

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Plasmid Dna ◽

Immune Modulation ◽

Viral Vector

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Immunology of viral-vector-mediated gene transfer into the brain: an evolutionary and developmental perspective

Trends in Immunology ◽

10.1016/s1471-4906(01)02063-4 ◽

2002 ◽

Vol 23 (1) ◽

pp. 23-30 ◽

Cited By ~ 82

Author(s):

Pedro R. Lowenstein

Keyword(s):

Gene Transfer ◽

Viral Vector ◽

Developmental Perspective ◽

The Brain

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Gene Therapy Applications of Non-Human Lentiviral Vectors

Viruses ◽

10.3390/v12101106 ◽

2020 ◽

Vol 12 (10) ◽

pp. 1106

Author(s):

Altar M. Munis

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Transgene Expression ◽

Viral Vector ◽

Lentiviral Vector ◽

Cell Therapies ◽

Dividing Cells ◽

Cell Genome ◽

Hiv 1

Recent commercialization of lentiviral vector (LV)-based cell therapies and successful reports of clinical studies have demonstrated the untapped potential of LVs to treat diseases and benefit patients. LVs hold notable and inherent advantages over other gene transfer agents based on their ability to transduce non-dividing cells, permanently transform target cell genome, and allow stable, long-term transgene expression. LV systems based on non-human lentiviruses are attractive alternatives to conventional HIV-1-based LVs due to their lack of pathogenicity in humans. This article reviews non-human lentiviruses and highlights their unique characteristics regarding virology and molecular biology. The LV systems developed based on these lentiviruses, as well as their successes and shortcomings, are also discussed. As the field of gene therapy is advancing rapidly, the use of LVs uncovers further challenges and possibilities. Advances in virology and an improved understanding of lentiviral biology will aid in the creation of recombinant viral vector variants suitable for translational applications from a variety of lentiviruses.

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Viral vectors for gene delivery and gene therapy within the endocrine system

Journal of Endocrinology ◽

10.1677/joe.0.1640103 ◽

2000 ◽

Vol 164 (2) ◽

pp. 103-118 ◽

Cited By ~ 52

Author(s):

D Stone ◽

A David ◽

F Bolognani ◽

PR Lowenstein ◽

MG Castro

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Gene Delivery ◽

Viral Vector ◽

Genetic Material ◽

Endocrine System ◽

Endocrine Disorders ◽

Advantages And Disadvantages ◽

Vector Systems

The transfer of genetic material into endocrine cells and tissues, both in vitro and in vivo, has been identified as critical for the study of endocrine mechanisms and the future treatment of endocrine disorders. Classical methods of gene transfer, such as transfection, are inefficient and limited mainly to delivery into actively proliferating cells in vitro. The development of viral vector gene delivery systems is beginning to circumvent these initial setbacks. Several kinds of viruses, including retrovirus, adenovirus, adeno-associated virus, and herpes simplex virus, have been manipulated for use in gene transfer and gene therapy applications. As different viral vector systems have their own unique advantages and disadvantages, they each have applications for which they are best suited. This review will discuss viral vector systems that have been used for gene transfer into the endocrine system, and recent developments in viral vector technology that may improve their use for endocrine applications - chimeric vectors, viral vector targeting and transcriptional regulation of transgene expression.

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Abstract 5423: rAAV-Mediated Gene Therapy with Inducible Nitric Oxide Synthase (iNOS) Affords Permanent Cardioprotection (1 Year) without Adverse Functional Consequences

Circulation ◽

10.1161/circ.118.suppl_18.s_547-d ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Qianhong Li ◽

Yiru Guo ◽

Wen-Jian Wu ◽

Qinghui Ou ◽

Santosh K Sanganalmath ◽

...

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Viral Vector ◽

Long Term Effects ◽

Inos Gene ◽

Inos Protein Expression ◽

Functional Consequences ◽

And Function ◽

Oxide Synthase

The ultimate goal of prophylactic gene therapy is to confer permanent protection against ischemia. Although gene therapy with iNOS is known to protect against myocardial infarction at 3 days and up to 2 months, the long-term effects of iNOS gene therapy on myocardial ischemic injury and function are unknown. To address this issue, we created a recombinant adeno-associated viral vector carrying the iNOS gene (rAAV/iNOS) which enables long-lasting transgene expression. Mice received injections in anterior LV wall of rAAV/LacZ or rAAV/iNOS; 1 year later, they underwent a 30-min coronary occlusion (O) and 4 h of reperfusion (R). iNOS gene transfer resulted in elevated iNOS protein expression (+ 2.9-fold vs. LacZ group, n=6, P<0.05; Fig ) and iNOS activity (+ 3.3-fold vs. LacZ group, n=4, P<0.05) 1 year later. Infarct size (% of risk region) was dramatically reduced at 1 year after iNOS gene transfer (13.5+/−2.2%, n=12, vs. 42.9+/−2.6%, n=12, in LacZ group; Fig ). The infarct-sparing effects of iNOS gene therapy at 1 year were as powerful as those observed 24 h after ischemic PC (six 4-min O/4-min R cycles) (16.3+/−2.3%, n=8; Fig ). Importantly, compared with the LacZ group (n=11), iNOS gene transfer (n=10) had no effect on LV dimensions or function for up to 1 year (at 1 year: LVEDD 4.4+/−0.1 vs. 4.2+/−0.2 mm; LVESD 2.9+/−0.1 vs. 2.9+/−0.2 mm; FS 34+/−1.8 vs. 32+/−2.6%; EF 56+/−2.3 vs. 60+/−2.9%) (echocardiography). These data demonstrate, for the first time, that rAAV-mediated iNOS gene transfer affords long-term, probably permanent (1 year) cardioprotection without adverse functional consequences, providing a strong rationale for further preclinical testing of prophylactic gene therapy.

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