Preclinical efficacy and safety of adeno-associated virus 5 alpha-galactosidase: A gene therapy for Fabry disease.

We developed a novel adeno-associated virus 5 gene therapy (AAV5-GLA) expressing human alpha-galactosidase A (GLA) under the control of a novel, small and strong, liver-restricted promoter. We assessed the preclinical potential of AAV5-GLA for treating Fabry disease, an X-linked hereditary metabolic disorder resulting from mutations in the gene encoding GLA that lead to accumulation of the substrates globotriaosylceramide and globotriaosylsphingosine, causing heart, kidney, and central nervous system dysfunction. Effects of intravenously administered AAV5-GLA were evaluated in (1) GLA-knockout mice aged 7-8 weeks (early in disease) and 20 weeks (nociception phenotype manifestation) and (2) cynomolgus macaques during an 8-week period.

Exon 1-targeting miRNA reduces the pathogenic exon 1 HTT protein in Huntington's disease models.

Huntington's disease (HD) is a fatal neurodegenerative disease caused by a trinucleotide repeat expansion in exon 1 of the huntingtin gene (HTT) that results in toxic gain of function and cell death. Despite its monogenic cause, the pathogenesis of HD is highly complex, and increasing evidence indicates that, in addition to the full-length (FL) mutant HTT protein, the expanded exon 1 HTT (HTTexon1) protein that is translated from the HTT1a transcript generated by aberrant splicing is prone to aggregate and might contribute to HD pathology. This finding suggests that reducing the expression of HTT1a might achieve a greater therapeutic benefit than targeting only FL mutant HTT.

AAV5-miHTT-mediated huntingtin lowering improves brain health in a Huntington's disease mouse model.

Huntingtin (HTT)-lowering therapies show great promise in treating Huntington's disease. We have developed a microRNA targeting human HTT that is delivered in an adeno-associated serotype 5 viral vector (AAV5-miHTT), and here use animal behaviour, MRI, non-invasive proton magnetic resonance spectroscopy and striatal RNA sequencing as outcome measures in preclinical mouse studies of AAV5-miHTT. The effects of AAV5-miHTT treatment were evaluated in homozygous Q175FDN mice, a mouse model of Huntington's disease with severe neuropathological and behavioural phenotypes.

Emerging Therapies for Huntington's Disease - Focus on N-Terminal Huntingtin and Huntingtin Exon 1.

Huntington's disease is a devastating heritable neurodegenerative disorder that is caused by the presence of a trinucleotide CAG repeat expansion in the gene, leading to a polyglutamine tract in the protein. Various mechanisms lead to the production of N-terminal Huntingtin protein fragments, which are reportedly more toxic than the full-length protein. In this review, we summarize the current knowledge on the production and toxicity of N-terminal Huntingtin protein fragments.

Enterovirus D68 Infection in Human Primary Airway and Brain Organoids: No Additional Role for Heparan Sulfate Binding for Neurotropism.

Enterovirus D68 (EV-D68) is an RNA virus that can cause outbreaks of acute flaccid paralysis (AFP), a polio-like disease. Before 2010, EV-D68 was a rare pathogen associated with mild respiratory symptoms, but the recent EV-D68 related increase in severe respiratory illness and outbreaks of AFP is not yet understood. An explanation for the rise in severe disease is that it may be due to changes in the viral genome resulting in neurotropism.

miRNA-Mediated Knockdown of ATXN3 Alleviates Molecular Disease Hallmarks in a Mouse Model for Spinocerebellar Ataxia Type 3.

Spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disorder caused by the expansion of a CAG repeat in the gene. This mutation leads to a toxic gain of function of the ataxin-3 protein, resulting in neuronal dysfunction and atrophy of specific brain regions over time. As ataxin-3 is a dispensable protein in rodents, ataxin-3 knockdown by gene therapy may be a powerful approach for the treatment of SCA3.

Secreted therapeutics: monitoring durability of microRNA-based gene therapies in the central nervous system.

The preclinical development of microRNA-based gene therapies for inherited neurodegenerative diseases is accompanied by translational challenges. Due to the inaccessibility of the brain to periodically evaluate therapy effects, accessible and reliable biomarkers indicative of dosing, durability and therapeutic efficacy in the central nervous system are very much needed. This is particularly important for viral vector-based gene therapies, in which a one-time administration results in long-term expression of active therapeutic molecules in the brain.

Widespread and sustained target engagement in Huntington's disease minipigs upon intrastriatal microRNA-based gene therapy.

Huntingtin (HTT)-lowering therapies hold promise to slow down neurodegeneration in Huntington's disease (HD). Here, we assessed the translatability and long-term durability of recombinant adeno-associated viral vector serotype 5 expressing a microRNA targeting human (rAAV5-miHTT) administered by magnetic resonance imaging-guided convention-enhanced delivery in transgenic HD minipigs. rAAV5-miHTT (1.

Intrastriatal Administration of AAV5-miHTT in Non-Human Primates and Rats Is Well Tolerated and Results in miHTT Transgene Expression in Key Areas of Huntington Disease Pathology.

Huntington disease (HD) is a fatal, neurodegenerative genetic disorder with aggregation of mutant Huntingtin protein (mutHTT) in the brain as a key pathological mechanism. There are currently no disease modifying therapies for HD; however, -lowering therapies hold promise. Recombinant adeno-associated virus serotype 5 expressing a microRNA that targets mRNA (AAV5-miHTT) is in development for the treatment of HD with promising results in rodent and minipig HD models.

A Perspective on Organoids for Virology Research.

Animal models and cell lines are invaluable for virology research and host-pathogen interaction studies. However, it is increasingly evident that these models are not sufficient to fully understand human viral diseases. With the advent of three-dimensional organotypic cultures, it is now possible to study viral infections in the human context.

Cerebral Organoids: A Human Model for AAV Capsid Selection and Therapeutic Transgene Efficacy in the Brain.

The development of gene therapies for central nervous system disorders is challenging because it is difficult to translate preclinical data from current and models to the clinic. Therefore, we developed induced pluripotent stem cell (iPSC)-derived cerebral organoids as a model for recombinant adeno-associated virus (rAAV) capsid selection and for testing efficacy of AAV-based gene therapy in a human context. Cerebral organoids are physiological 3D structures that better recapitulate the human brain compared with 2D cell lines.

Development of an AAV-Based MicroRNA Gene Therapy to Treat Machado-Joseph Disease.

Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is a progressive neurodegenerative disorder caused by a CAG expansion in the gene. The expanded CAG repeat is translated into a prolonged polyglutamine repeat in the ataxin-3 protein and accumulates within inclusions, acquiring toxic properties, which results in degeneration of the cerebellum and brain stem. In the current study, a non-allele-specific silencing approach was investigated using artificial microRNAs engineered to target various regions of the gene (miATXN3).

Potent and sustained huntingtin lowering via AAV5 encoding miRNA preserves striatal volume and cognitive function in a humanized mouse model of Huntington disease.

Huntington disease (HD) is a fatal neurodegenerative disease caused by a pathogenic expansion of a CAG repeat in the huntingtin (HTT) gene. There are no disease-modifying therapies for HD. Artificial microRNAs targeting HTT transcripts for degradation have shown preclinical promise and will soon enter human clinical trials.

AAV5-miHTT Lowers Huntingtin mRNA and Protein without Off-Target Effects in Patient-Derived Neuronal Cultures and Astrocytes.

Huntington disease (HD) is a fatal neurodegenerative genetic disorder, thought to reflect a toxic gain of function in huntingtin (Htt) protein. Adeno-associated viral vector serotype 5 (AAV5)- microRNA targeting huntingtin (miHTT) is a HD gene-therapy candidate that efficiently lowers using RNAi. This study analyzed the efficacy and potential for off-target effects with AAV5-miHTT in neuronal and astrocyte cell cultures differentiated from induced pluripotent stem cells (iPSCs) from two individuals with HD (HD71 and HD180).

Rescue of spinal muscular atrophy mouse models with AAV9-Exon-specific U1 snRNA.

Spinal Muscular Atrophy results from loss-of-function mutations in SMN1 but correcting aberrant splicing of SMN2 offers hope of a cure. However, current splice therapy requires repeated infusions and is expensive. We previously rescued SMA mice by promoting the inclusion of a defective exon in SMN2 with germline expression of Exon-Specific U1 snRNAs (ExspeU1).

AAV5-miHTT Gene Therapy Demonstrates Sustained Huntingtin Lowering and Functional Improvement in Huntington Disease Mouse Models.

Huntington disease (HD) is a fatal neurodegenerative disorder caused by an autosomal dominant CAG repeat expansion in the () gene. The translated expanded polyglutamine repeat in the HTT protein is known to cause toxic gain of function. We showed previously that strong HTT lowering prevented neuronal dysfunction in HD rodents and minipigs after single intracranial injection of adeno-associated viral vector serotype 5 expressing a microRNA targeting human (AAV5-miHTT).

Targeting RNA-Mediated Toxicity in C9orf72 ALS and/or FTD by RNAi-Based Gene Therapy.

A hexanucleotide GGGGCC expansion in intron 1 of chromosome 9 open reading frame 72 (C9orf72) gene is the most frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The corresponding repeat-containing sense and antisense transcripts cause a gain of toxicity through the accumulation of RNA foci in the nucleus and deposition of dipeptide-repeat (DPR) proteins in the cytoplasm of the affected cells. We have previously reported on the potential of engineered artificial anti-C9orf72-targeting miRNAs (miC) targeting C9orf72 to reduce the gain of toxicity caused by the repeat-containing transcripts.

Artificial MicroRNAs Targeting C9orf72 Can Reduce Accumulation of Intra-nuclear Transcripts in ALS and FTD Patients.

The most common pathogenic mutation in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is an intronic GGGGCC (GC) repeat in the chromosome 9 open reading frame 72 (C9orf72) gene. Cellular toxicity due to RNA foci and dipeptide repeat (DPR) proteins produced by the sense and antisense repeat-containing transcripts is thought to underlie the pathogenesis of both diseases. RNA sequencing (RNA-seq) data of C9orf72-ALS patients and controls were analyzed to better understand the sequence conservation of C9orf72 in patients.

AAV5-miHTT Gene Therapy Demonstrates Broad Distribution and Strong Human Mutant Huntingtin Lowering in a Huntington's Disease Minipig Model.

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin gene. Previously, we showed strong huntingtin reduction and prevention of neuronal dysfunction in HD rodents using an engineered microRNA targeting human huntingtin, delivered via adeno-associated virus (AAV) serotype 5 vector with a transgene encoding an engineered miRNA against HTT mRNA (AAV5-miHTT). One of the challenges of rodents as a model of neurodegenerative diseases is their relatively small brain, making successful translation to the HD patient difficult.

Transcriptional profiling and biomarker identification reveal tissue specific effects of expanded ataxin-3 in a spinocerebellar ataxia type 3 mouse model.

Background: Spinocerebellar ataxia type 3 (SCA3) is a progressive neurodegenerative disorder caused by expansion of the polyglutamine repeat in the ataxin-3 protein. Expression of mutant ataxin-3 is known to result in transcriptional dysregulation, which can contribute to the cellular toxicity and neurodegeneration. Since the exact causative mechanisms underlying this process have not been fully elucidated, gene expression analyses in brains of transgenic SCA3 mouse models may provide useful insights.

Translation of MicroRNA-Based Huntingtin-Lowering Therapies from Preclinical Studies to the Clinic.

The single mutation underlying the fatal neuropathology of Huntington's disease (HD) is a CAG triplet expansion in exon 1 of the huntingtin (HTT) gene, which gives rise to a toxic mutant HTT protein. There have been a number of not yet successful therapeutic advances in the treatment of HD. The current excitement in the HD field is due to the recent development of therapies targeting the culprit of HD either at the DNA or RNA level to reduce the overall mutant HTT protein.

In vivo proof-of-concept of removal of the huntingtin caspase cleavage motif-encoding exon 12 approach in the YAC128 mouse model of Huntington's disease.

Huntington's disease (HD) is a progressive autosomal dominant disease, caused by a CAG repeat expansion in the HTT gene, resulting in an expanded polyglutamine stretch at the N-terminal of the huntingtin protein. An important event in HD pathogenesis appears to be the proteolysis of the mutant protein, which forms N-terminal huntingtin fragments. These fragments form insoluble aggregates and are found in nuclei and cytoplasm of affected neurons where they interfere with normal cell functioning.