Huntington ́s disease (HD) is a progressive neurodegenerative disease with onset in adulthood that leads to a complete disability and death in approximately 20 years after onset of symptoms. HD is caused by an expansion of a CAG triplet in the gene for huntingtin. Although the disease causes most damage to striatal neurons, other parts of the nervous system and many peripheral tissues are also markedly affected. Besides huntingtin malfunction, mitochondrial impairment has been previously described as an important player in HD. This study focuses on mitochondrial structure and function in cultivated skin fibroblasts from 10 HD patients to demonstrate mitochondrial impairment in extra-neuronal tissue. Mitochondrial structure, mitochondrial fission, and cristae organization were significantly disrupted and signs of elevated apoptosis were found. In accordance with structural changes, we also found indicators of functional alteration of mitochondria. Mitochondrial disturbances presented in fibroblasts from HD patients confirm that the energy metabolism damage in HD is not localized only to the central nervous system, but also may play role in the pathogenesis of HD in peripheral tissues. Skin fibroblasts can thus serve as a suitable cellular model to make insight into HD pathobiochemical processes and for the identification of possible targets for new therapies.
Huntington's disease (HD), as well as Parkinson's disease and Alzheimer's disease, belong to a group of neurodegenerative diseases characterized by common features, such as the progressive loss of neurons and the presence of pathogenic forms of misfolded protein aggregates. A quality control system such as autophagy is crucial for the clearance of protein aggregates and dysfunctional organelles and thus essential for the maintenance of neuronal homeostasis. The constant high energy demand of neuronal tissue links neurodegeneration to mitochondria. Inefficient removal of damaged mitochondria is thought to contribute to the pathogenesis of neurodegenerative diseases such as HD. In addition, direct involvement of the huntingtin protein in the autophagic machinery has been described. In this review, we focus on mitophagy, a selective form of autophagy responsible for mitochondrial turnover. We also discuss the relevance of pharmacological regulation of mitophagy in the future therapeutic approach to neurodegenerations, including HD.
- MeSH
- biologické přípravky terapeutické užití MeSH
- Huntingtonova nemoc farmakoterapie genetika metabolismus patologie MeSH
- lidé MeSH
- mitochondrie genetika metabolismus patologie MeSH
- mitofagie fyziologie MeSH
- neurony metabolismus patologie MeSH
- neuroprotektivní látky terapeutické užití MeSH
- protein huntingtin genetika metabolismus MeSH
- proteinové agregáty fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Huntington's disease (HD) is a rare hereditary autosomal dominant neurodegenerative disorder, which is caused by expression of mutant huntingtin protein (mHTT) with an abnormal number of glutamine repeats in its N terminus, and characterized by intracellular mHTT aggregates (inclusions) in the brain. Exosomes are small extracellular vesicles that are secreted generally by all cell types and can be isolated from almost all body fluids such as blood, urine, saliva, and cerebrospinal fluid. Exosomes may participate in the spreading of toxic misfolded proteins across the central nervous system in neurodegenerative diseases. In HD, such propagation of mHTT was observed both in vitro and in vivo. On the other hand, exosomes might carry molecules with neuroprotective effects. In addition, due to their capability to cross blood-brain barrier, exosomes hold great potential as sources of biomarkers available from periphery or carriers of therapeutics into the central nervous system. In this review, we discuss the emerging roles of exosomes in HD pathogenesis, diagnosis, and therapy.
Skeletal muscle wasting and atrophy is one of the more severe clinical impairments resulting from the progression of Huntington's disease (HD). Mitochondrial dysfunction may play a significant role in the etiology of HD, but the specific condition of mitochondria in muscle has not been widely studied during the development of HD. To determine the role of mitochondria in skeletal muscle during the early stages of HD, we analyzed quadriceps femoris muscle from 24-, 36-, 48- and 66-month-old transgenic minipigs that expressed the N-terminal portion of mutated human huntingtin protein (TgHD) and age-matched wild-type (WT) siblings. We found altered ultrastructure of TgHD muscle tissue and mitochondria. There was also significant reduction of activity of citrate synthase and respiratory chain complexes (RCCs) I, II and IV, decreased quantity of oligomycin-sensitivity conferring protein (OSCP) and the E2 subunit of pyruvate dehydrogenase (PDHE2), and differential expression of optic atrophy 1 protein (OPA1) and dynamin-related protein 1 (DRP1) in the skeletal muscle of TgHD minipigs. Statistical analysis identified several parameters that were dependent only on HD status and could therefore be used as potential biomarkers of disease progression. In particular, the reduction of biomarker RCCII subunit SDH30 quantity suggests that similar pathogenic mechanisms underlie disease progression in TgHD minipigs and HD patients. The perturbed biochemical phenotype was detectable in TgHD minipigs prior to the development of ultrastructural changes and locomotor impairment, which become evident at the age of 48 months. Mitochondrial disturbances may contribute to energetic depression in skeletal muscle in HD, which is in concordance with the mobility problems observed in this model.This article has an associated First Person interview with the first author of the paper.
- MeSH
- DNA metabolismus MeSH
- energetický metabolismus * MeSH
- geneticky modifikovaná zvířata MeSH
- Huntingtonova nemoc metabolismus patologie MeSH
- kosterní svaly metabolismus ultrastruktura MeSH
- lidé MeSH
- miniaturní prasata MeSH
- mitochondriální proteiny metabolismus MeSH
- modely nemocí na zvířatech * MeSH
- mutace MeSH
- oxidativní fosforylace MeSH
- prasata MeSH
- progrese nemoci MeSH
- protein huntingtin genetika MeSH
- svalové mitochondrie metabolismus ultrastruktura MeSH
- tělesná hmotnost MeSH
- transport elektronů MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Alterations in mitochondrial parameters are an important hallmark of Huntington's disease (HD). The ubiquitous expression of mutant huntingtin raises the prospect that mitochondrial disturbances can also be detected and monitored through buccal epithelial cells. In a group of 34 patients with Huntington's disease and a group of 22 age-related healthy volunteers, respiratory complex I and IV protein quantities in buccal epithelial cells were measured using the dipstick immunocapture assay. The protein quantity of respiratory complex I correlates with age (r = 0.427, P = 0.026, FWE-P = 0.156) in the patient group, but not in the group of healthy subjects. Our non-invasive approach allows us to obtain valuable information for the studies of mitochondrial biochemical parameters in patients with neurodegenerative diseases and could also be useful in epidemiological studies.
- MeSH
- Huntingtonova nemoc metabolismus MeSH
- kachexie metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- respirační komplex I metabolismus MeSH
- respirační komplex IV metabolismus MeSH
- studie případů a kontrol MeSH
- ústní sliznice metabolismus MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
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.This article has an associated First Person interview with the first author of the paper.
- MeSH
- chování zvířat * MeSH
- degenerace nervu patologie MeSH
- deoxyguanosin analogy a deriváty metabolismus MeSH
- energetický metabolismus MeSH
- geneticky modifikovaná zvířata MeSH
- genom MeSH
- Huntingtonova nemoc metabolismus patologie MeSH
- lidé MeSH
- miniaturní prasata MeSH
- mitochondrie metabolismus MeSH
- modely nemocí na zvířatech MeSH
- oprava DNA MeSH
- orgánová specificita MeSH
- poškození DNA MeSH
- prasata MeSH
- protein huntingtin metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
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. This is particularly relevant for gene therapy approaches, where distribution achieved upon local administration into the parenchyma is likely dependent on brain size and structure. Here, we aimed to demonstrate the translation of huntingtin-lowering gene therapy to a large-animal brain. We investigated the feasibility, efficacy, and tolerability of one-time intracranial administration of AAV5-miHTT in the transgenic HD (tgHD) minipig model. We detected widespread dose-dependent distribution of AAV5-miHTT throughout the tgHD minipig brain that correlated with the engineered microRNA expression. Both human mutant huntingtin mRNA and protein were significantly reduced in all brain regions transduced by AAV5-miHTT. The combination of widespread vector distribution and extensive huntingtin lowering observed with AAV5-miHTT supports the translation of a huntingtin-lowering gene therapy for HD from preclinical studies into the clinic.
- MeSH
- Dependovirus genetika MeSH
- expanze trinukleotidových repetic genetika MeSH
- genetická terapie metody MeSH
- genetické vektory genetika MeSH
- geneticky modifikovaná zvířata MeSH
- Huntingtonova nemoc genetika metabolismus terapie MeSH
- lidé MeSH
- mikro RNA genetika metabolismus MeSH
- miniaturní prasata MeSH
- modely nemocí na zvířatech MeSH
- prasata MeSH
- protein huntingtin genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Huntington's disease (HD) is an autosomal-dominant, progressive neurodegenerative disorder with motor, cognitive, behavioral and metabolic symptoms. HD patients exhibit an altered response to stress which is reflected in changes of cortisol levels. Large animal models of HD such as the Libechov minipig are currently explored in preclinical studies to improve translational reliability and assessing behavior is of interest. OBJECTIVE: This study aimed to investigate whether cortisol metabolism and response to stress are changed in minipigs transgenic for the Huntington gene (tgHD) compared to wildtype (wt) animals suggesting that cortisol may be used as a marker for stress in minipigs. METHODS: Thirty-two Libechov minipigs (14 tgHD and 18 wt) were tested before, during and after a stressor, i.e., a hoof trimming procedure, was applied at baseline and after one year. A total of six saliva samples were collected at each assessment and cortisol was measured. In addition, body temperature and respiratory rate were assessed at three pre-determined points during each hoof trimming procedure. RESULTS: All minipigs showed a rise of cortisol in response to the hoof trimming stressor similarly to cortisol changes induced by stress observed in humans. No relevant differences were detected between tgHD and wt minipigs. CONCLUSION: Cortisol testing for the assessment of stress compensation, e.g., during hoof trimming, is feasible and well tolerated in wt and tgHD minipigs. To elucidate the time profile of cortisol responses to stressors further studies with assessments at multiple time points and exploration of the diurnal profiles of cortisol in minipigs are recommended.
- MeSH
- dechová frekvence MeSH
- geneticky modifikovaná zvířata MeSH
- Huntingtonova nemoc metabolismus MeSH
- hydrokortison metabolismus MeSH
- miniaturní prasata MeSH
- modely nemocí na zvířatech MeSH
- ověření koncepční studie MeSH
- prasata MeSH
- psychický stres metabolismus MeSH
- referenční hodnoty MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Diffusion-weighted magnetic resonance (DW-MR) is an important diagnostic tool in Huntington disease (HD), a fatal hereditary neurodegenerative disorder. To clarify the nature of diffusivity changes in HD, we compared the apparent diffusion coefficient of water (ADCW) acquired by DW-MR with extracellular space volume fraction α and tortuosity λ, measured by the iontophoretic method in the R6/2 mouse model of HD and in wild-type controls (WT). In anisotropic globus pallidus (GP), diffusion measurements were performed in the mediolateral (x), rostrocaudal (y), and ventrodorsal (z) axes. In HD animals, we detected an increase in ADCWin all axes and larger α than in WT mice. No significant difference between WT and HD mice was found in the values of tortuosity (λx, λy, λz). Despite structural changes in GP, diffusion anisotropy was unaffected in HD mice. Immunohistochemical analysis revealed in HD mice weaker expression of extracellular matrix and a decrease in neuron numbers compared with WT mice. Glial fibrillary acidic protein staining detected astrogliosis-like changes in the morphology of astrocytic processes in HD GP. In the somatosensory cortex, no significant differences in the studied parameters were found. We conclude that in the R6/2 model of HD, a decrease in the number of neurons in the GP results in increased ADCWand α values. Values of λ were not significantly changed as the increase of diffusion obstacles formed by reactive astrocytes was compensated for by the extracellular matrix reduction. © 2016 Wiley Periodicals, Inc.
- MeSH
- difuzní magnetická rezonance metody MeSH
- Huntingtonova nemoc diagnostické zobrazování genetika metabolismus MeSH
- lidé MeSH
- modely nemocí na zvířatech * MeSH
- mozek diagnostické zobrazování metabolismus MeSH
- myši inbrední C57BL MeSH
- myši inbrední CBA MeSH
- myši transgenní MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: As novel treatment approaches for Huntington's disease (HD) evolve, the use of transgenic (tg) large animal models has been considered for preclinical safety and efficacy assessments. It is hoped that large animal models may provide higher reliability in translating preclinical findings to humans, e.g., by using similar endpoints and biomarkers. NEW METHOD: We here investigated the feasibility to conduct MRI assessments in a recently developed tgHD model in the Libechov minipig. The model is characterized by high genetic homology to humans and a similar body mass and compartments. The minipig brain provides anatomical features that are attractive for imaging studies and could be used as endpoints for disease modifying preclinical studies similar to human HD. RESULTS: We demonstrate that complex MRI protocols can be successfully acquired with tgHD and wild type (wt) Libechov minipigs. We show that acquisition of anatomical images applicable for volumetric assessments is feasible and outline the development of a segmented MRI brain atlas. Similarly diffusion-weighted imaging (DWI) including fiber tractography is presented. We also demonstrate the feasibility to conduct in vivo metabolic assessments using MR spectroscopy. COMPARISON WITH EXISTING METHODS: In human HD, these MRI methods are already validated and used as reliable biomarker of disease progression even before the onset of a clinical motor phenotype. CONCLUSIONS: The results show that the minipig brain is well suited for MRI assessments in preclinical studies. We conclude that further characterization of phenotypical differences between tg and wt animals in sufficiently powered cross-sectional and longitudinal studies is warranted.
- MeSH
- geneticky modifikovaná zvířata MeSH
- Huntingtonova nemoc diagnostické zobrazování metabolismus MeSH
- magnetická rezonanční tomografie * přístrojové vybavení metody MeSH
- miniaturní prasata * MeSH
- modely nemocí na zvířatech * MeSH
- mozek diagnostické zobrazování metabolismus MeSH
- neurozobrazování přístrojové vybavení metody MeSH
- prasata MeSH
- protonová magnetická rezonanční spektroskopie * přístrojové vybavení metody MeSH
- velikost orgánu MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
