(1) Background: Huntington's disease (HD) is rare incurable hereditary neurodegenerative disorder caused by CAG repeat expansion in the gene coding for the protein huntingtin (HTT). Mutated huntingtin (mHTT) undergoes fragmentation and accumulation, affecting cellular functions and leading to neuronal cell death. Porcine models of HD are used in preclinical testing of currently emerging disease modifying therapies. Such therapies are aimed at reducing mHTT expression, postpone the disease onset, slow down the progression, and point out the need of biomarkers to monitor disease development and therapy efficacy. Recently, extracellular vesicles (EVs), particularly exosomes, gained attention as possible carriers of disease biomarkers. We aimed to characterize HTT and mHTT forms/fragments in blood plasma derived EVs in transgenic (TgHD) and knock-in (KI-HD) porcine models, as well as in HD patients' plasma. (2) Methods: Small EVs were isolated by ultracentrifugation and HTT forms were visualized by western blotting. (3) Results: The full length 360 kDa HTT co-isolated with EVs from both the pig model and HD patient plasma. In addition, a ~70 kDa mutant HTT fragment was specific for TgHD pigs. Elevated total huntingtin levels in EVs from plasma of HD groups compared to controls were observed in both pig models and HD patients, however only in TgHD were they significant (p = 0.02). (4) Conclusions: Our study represents a valuable initial step towards the characterization of EV content in the search for HD biomarkers.

• Klíčová slova
• Huntington´s disease, KI-HD, TgHD, biomarker, exosome, extracellular vesicle, fragment, huntingtin, neurodegenerative disease, pig model,
• MeSH
• biologické markery MeSH
• extracelulární vezikuly * metabolismus   MeSH
• Huntingtonova nemoc * metabolismus   MeSH
• krevní plazma metabolismus   MeSH
• lidé MeSH
• prasata MeSH
• proteiny nervové tkáně genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické markery MeSH
• proteiny nervové tkáně MeSH

Huntington disease (HD) is the most frequent monogenetic neurodegenerative disease and can be unequivocally diagnosed even in the preclinical stage, at least in all individuals in whom the CAG expansion mutation in the huntingtin gene (HTT) is in the range of full penetrance. Therefore, important preconditions for an intervention early in the disease process are met, rendering modification of the course of the disease in a clinically meaningful way possible. In this respect, HD can be viewed as a model disorder for exploring neuroprotective treatment approaches. In the past emphasis was placed on the compensation of a suspected neurotransmitter deficit (GABA) analogous to Parkinson's disease and on classical neuroprotective strategies to influence hypothetical common pathways in neurodegenerative diseases (e.g., excitotoxicity, mitochondrial dysfunction, oxidative stress). With the discovery of the causative HTT mutation in 1993, therapeutic research increasingly focused on intervening as proximally as possible in the chain of pathophysiological events. Currently, an important point of intervention is the HTT mRNA with the aim of reducing the continued production of mutant huntingtin gene products and thus relieving the body of their detrimental actions. To this end, various treatment modalities (single-stranded DNA and RNA, divalent RNA and zinc finger repressor complexes, orally available splice modulators) were developed and are currently in clinical trials (phases I-III) or in late stages of preclinical development. In addition, there is the notion that it may be possible to modify the length of the somatically unstable CAG mutation, i.e. its increase in the brain during the lifetime, thereby slowing the progression of HD.

Die Huntington-Krankheit (HK) ist die häufigste monogenetische neurodegenerative Erkrankung und kann bereits im präklinischen Stadium zweifelsfrei diagnostiziert werden, zumindest in allen Fällen, bei denen die CAG-Expansionsmutation im Huntingtin-Gen (HTT) im Bereich der vollen Penetranz liegt. Wichtige Voraussetzungen für eine früh im Krankheitsprozess einsetzende und deshalb den weiteren Verlauf der Krankheit in klinisch relevanter Weise modifizierende Therapie sind damit gegeben und machen die HK zu einer Modellerkrankung für neuroprotektive Behandlungsansätze. In der Vergangenheit lag der Schwerpunkt auf dem Ausgleich vermuteter Neurotransmitterdefizite (GABA) analog zur Parkinson-Erkrankung und auf klassischen neuroprotektiven Strategien zur Beeinflussung hypothetischer gemeinsamer Endstrecken neurodegenerativer Erkrankungen (z. B. Exzitotoxizität, mitochondriale Dysfunktion, oxidativer Stress etc.). Mit der Entdeckung der krankheitsverursachenden HTT-Mutation im Jahr 1993 fokussierte sich die Therapieforschung zunehmend darauf, soweit proximal wie möglich in die pathophysiologische Ereigniskette einzugreifen. Ein wichtiger Ansatzpunkt ist hier die HTT-mRNA mit dem Ziel, die Nachproduktion mutierter Huntingtin-Genprodukte zu senken und damit den Körper von deren schädigenden Auswirkungen zu entlasten; zu diesem Zweck sind verschiedene Behandlungsmodalitäten (einzelsträngige DNA und RNA, divalente RNA und Zinkfinger-Repressorkomplexe, oral verfügbare Spleißmodulatoren) entwickelt worden, die sich in der klinischen Prüfung (Phase I–III) oder in späten Stadien der präklinischen Entwicklung befinden. Zudem zeichnet sich ab, dass es möglich sein könnte, die Länge der somatisch instabilen, d. h. über die Lebenszeit v. a. im Hirngewebe zunehmende CAG-Mutation selbst zu beeinflussen und die Progression der HK hierdurch zu bremsen.

• Klíčová slova
• Antisense oligonucleotide, Disease modification, Gene therapy, HTT mRNA, Neuroprotection,
• MeSH
• antisense oligonukleotidy MeSH
• Huntingtonova nemoc * diagnóza   farmakoterapie   genetika   MeSH
• lidé MeSH
• mozek MeSH
• mutace genetika   MeSH
• neurodegenerativní nemoci * MeSH
• protein huntingtin genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antisense oligonukleotidy MeSH
• protein huntingtin 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.

• Klíčová slova
• Huntington’s disease, biomarker, exosome, extracellular vesicle, huntingtin, neurodegeneration, polyQ, therapy,
• MeSH
• biologické modely MeSH
• exozómy metabolismus   MeSH
• Huntingtonova nemoc metabolismus   MeSH
• lékové transportní systémy MeSH
• lidé MeSH
• protein huntingtin metabolismus   MeSH
• sbalování proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• protein huntingtin MeSH

Genetically modified rodent models of Huntington's disease (HD) have been especially valuable to our understanding of HD pathology and the mechanisms by which the mutant HTT gene alters physiology. However, due to inherent differences in genetics, neuroanatomy, neurocircuitry and neurophysiology, animal models do not always faithfully or fully recapitulate human disease features or adequately predict a clinical response to treatment. Therefore, conducting translational studies of candidate HD therapeutics only in a single species (i.e. mouse disease models) may not be sufficient. Large animal models of HD have been shown to be valuable to the HD research community and the expectation is that the need for translational studies that span rodent and large animal models will grow. Here, we review the large animal models of HD that have been created to date, with specific commentary on differences between the models, the strengths and disadvantages of each, and how we can advance useful models to study disease pathophysiology, biomarker development and evaluation of promising therapeutics.

• Klíčová slova
• Minipigs, nonhuman primates, sheep, therapeutics,
• MeSH
• geneticky modifikovaná zvířata * MeSH
• Huntingtonova nemoc * genetika   patologie   patofyziologie   terapie   MeSH
• miniaturní prasata MeSH
• modely nemocí na zvířatech * MeSH
• ovce MeSH
• prasata MeSH
• primáti MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Sandwich ELISA-based methods use Abs that target the expanded polyglutamine (polyQ) tract to quantify mutant huntingtin (mHTT). Using Meso Scale Discovery (MSD) assay, the mHTT signal detected with MW1 Ab correlated with polyQ length and doubled with a difference of only 7 glutamine residues between equivalent amounts of purified mHTTexon1 proteins. Similar polyQ length-dependent effects on MSD signals were confirmed using endogenous full length mHTT from brains of Huntington's disease (HD) knock-in (KI) mice. We used this avidity bias to devise a method to assess average CAG repeat instability at the protein level in a mixed population of HTT proteins present in tissues. Signal detected for average polyQ length quantification at the protein level by our method exhibited a strong correlation with average CAG repeat length at the genomic DNA level determined by PCR method in striatal tissue homogenates from HdhQ140 KI mice and in human HD postmortem cortex. This work establishes that CAG repeat instability in mutant HTT is reflected at the protein level.

• MeSH
• DNA genetika   MeSH
• exony genetika   MeSH
• expanze trinukleotidových repetic genetika   MeSH
• lidé MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• peptidy genetika   MeSH
• protein huntingtin chemie   genetika   MeSH
• protilátky metabolismus   MeSH
• sekvence aminokyselin MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• peptidy MeSH
• polyglutamine MeSH Prohlížeč
• protein huntingtin MeSH
• protilátky MeSH