Porcine Model of Huntington\u27s Disease

At present, we are probably the only research facility to be breeding transgenic Huntington\u27s disease minipigs (TgHD). These minipigs express N‐terminal part of human mutated huntingtin including 124Q under the control of human huntingtin promoter. The founder animal, born in 2009, gave birth to four subsequent generations with an equal contribution of wild‐type (WT) and transgenic (TgHD) piglets in all litters. We take different approaches, some of which are unique for large animal models, to study the phenotype development comparing WT and TgHD siblings. In this chapter, we review these approaches and the phenotype progression in the minipigs. Additionally, we outline perspectives in generation of new models using novel methodology and the potential of pig models in preclinical HD studies

Stem Cells for Huntington's Disease (SC4HD): An International Consortium to Facilitate Stem Cell-Based Therapy for Huntington's Disease

Huntington's disease (HD) research is entering an exciting phase, with new approaches such as huntingtin lowering strategies and cell therapies on the horizon. Technological advances to direct the differentiation of stem cells to desired neural types have opened new strategies for restoring damaged neuronal circuits in HD. However, challenges remain in the implementation of cell therapy approaches for patients suffering from HD. Cell therapies, together with other invasive approaches including allele specific oligonucleotides (ASOs) and viral delivery of huntingtin-lowering agents, require direct delivery of the therapeutic agents locally into the brain or cerebrospinal fluid. Delivering substances directly into the brain is complex and presents multiple challenges, including those related to regulatory requirements, safety and efficacy, surgical instrumentation, trial design, patient profiles, and selection of suitable and sensitive primary and secondary outcomes. In addition, production of clinical grade cell-based medicinal products also requires adherence to regulatory standards with extensive quality control of the protocols and cell products across different laboratories and production centers. Currently, there is no consensus on how best to address these challenges. Here we describe the formation of Stem Cells For Huntington's Disease (SC4HD: https://www.sc4hd.org/), a network of researchers and clinicians working to develop guidance and greater standardization for the HD field for stem cell based transplantation therapy for HD with a mission to work to develop criteria and guidance for development of a neural intra-cerebral stem cell-based therapy for HD

Early disruption of photoreceptor cell architecture and loss of vision in a humanized pig model of usher syndromes

Usher syndrome (USH) is the most common form of monogenic deaf-blindness. Loss of vision is untreatable and there are no suitable animal models for testing therapeutic strategies of the ocular constituent of USH, so far. By introducing a human mutation into the harmonin-encoding USH1C gene in pigs, we generated the first translational animal model for USH type 1 with characteristic hearing defect, vestibular dysfunction, and visual impairment. Changes in photoreceptor architecture, quantitative motion analysis, and electroretinography were characteristics of the reduced retinal virtue in USH1C pigs. Fibroblasts from USH1C pigs or USH1C patients showed significantly elongated primary cilia, confirming USH as a true and general ciliopathy. Primary cells also proved their capacity for assessing the therapeutic potential of CRISPR/Cas-mediated gene repair or gene therapy in vitro. AAV-based delivery of harmonin into the eye of USH1C pigs indicated therapeutic efficacy in vivo

Age-Related Oxidative Changes in Primary Porcine Fibroblasts Expressing Mutated Huntingtin

Background: Huntington’s disease (HD) is a devastating neurodegenerative disorder caused by CAG triplet expansions in the huntingtin gene. Oxidative stress is linked to HD pathology, although it is not clear whether this is an effect or a mediator of disease. The transgenic (TgHD) minipig expresses the N-terminal part of human-mutated huntingtin and represents a unique model to investigate therapeutic strategies towards HD. A more detailed characterization of this model is needed to fully utilize its potential. Methods: In this study, we focused on the molecular and cellular features of fibroblasts isolated from TgHD minipigs and the wild-type (WT) siblings at different ages, pre-symptomatic at the age of 24–36 months and with the onset of behavioural symptoms at the age of 48 months. We measured oxidative stress, the expression of oxidative stress-related genes, proliferation capacity along with the expression of cyclin B1 and D1 proteins, cellular permeability, and the integrity of the nuclear DNA (nDNA) and mitochondrial DNA in these cells. Results: TgHD fibroblasts isolated from 48-month-old animals showed increased oxidative stress, which correlated with the overexpression of SOD2 encoding mitochondrial superoxide dismutase 2, and the NEIL3 gene encoding DNA glycosylase involved in replication-associated repair of oxidized DNA. TgHD cells displayed an abnormal proliferation capacity and permeability. We further demonstrated increased nDNA damage in pre-symptomatic TgHD fibroblasts (isolated from animals aged 24–36 months). Conclusions: Our results unravel phenotypic alterations in primary fibroblasts isolated from the TgHD minipig model at the age of 48 months. Importantly, nDNA damage appears to precede these phenotypic alterations. Our results highlight the impact of fibroblasts from TgHD minipigs in studying the molecular mechanisms of HD pathophysiology that gradually occur with age

A transgenic minipig model of Huntington’s disease shows early signs of behavioral and molecular pathologies

Huntington's disease (HD) is a monogenic, progressive, neurodegenerative disorder with currently no available treatment. The Libechov transgenic minipig model for HD (TgHD) displays neuroanatomical similarities to humans and exhibits slow disease progression, and is therefore more powerful than available mouse models for the development of therapy. The phenotypic characterization of this model is still ongoing, and it is essential to validate biomarkers to monitor disease progression and intervention. In this study, the behavioral phenotype (cognitive, motor and behavior) of the TgHD model was assessed, along with biomarkers for mitochondrial capacity, oxidative stress, DNA integrity and DNA repair at different ages (24, 36 and 48 months), and compared with age-matched controls. The TgHD minipigs showed progressive accumulation of the mutant huntingtin (mHTT) fragment in brain tissue and exhibited locomotor functional decline at 48 months. Interestingly, this neuropathology progressed without any significant age-dependent changes in any of the other biomarkers assessed. Rather, we observed genotype-specific effects on mitochondrial DNA (mtDNA) damage, mtDNA copy number, 8-oxoguanine DNA glycosylase activity and global level of the epigenetic marker 5-methylcytosine that we believe is indicative of a metabolic alteration that manifests in progressive neuropathology. Peripheral blood mononuclear cells (PBMCs) were relatively spared in the TgHD minipig, probably due to the lack of detectable mHTT. Our data demonstrate that neuropathology in the TgHD model has an age of onset of 48 months, and that oxidative damage and electron transport chain impairment represent later states of the disease that are not optimal for assessing interventions

Stem Cells for Huntington’s Disease (SC4HD): An International Consortium to Facilitate Stem Cell-Based Therapy for Huntington’s Disease

International audienceHuntington’s disease (HD) research is entering an exciting phase, with new approaches such as huntingtin lowering strategies and cell therapies on the horizon. Technological advances to direct the differentiation of stem cells to desired neural types have opened new strategies for restoring damaged neuronal circuits in HD. However, challenges remain in the implementation of cell therapy approaches for patients suffering from HD. Cell therapies, together with other invasive approaches including allele specific oligonucleotides (ASOs) and viral delivery of huntingtin-lowering agents, require direct delivery of the therapeutic agents locally into the brain or cerebrospinal fluid. Delivering substances directly into the brain is complex and presents multiple challenges, including those related to regulatory requirements, safety and efficacy, surgical instrumentation, trial design, patient profiles, and selection of suitable and sensitive primary and secondary outcomes. In addition, production of clinical grade cell-based medicinal products also requires adherence to regulatory standards with extensive quality control of the protocols and cell products across different laboratories and production centers. Currently, there is no consensus on how best to address these challenges. Here we describe the formation of Stem Cells For Huntington’s Disease (SC4HD: https://www.sc4hd.org/), a network of researchers and clinicians working to develop guidance and greater standardization for the HD field for stem cell based transplantation therapy for HD with a mission to work to develop criteria and guidance for development of a neural intra-cerebral stem cell-based therapy for HD