In the last two decades, a school of thought emerged that perceives male reproductive health, testicular function, and sperm output as a sentry for general, somatic health. Large-scale epidemiologic studies have already linked the reduced sperm count to increased risk of chronic somatic disease (e.g., cancer, cardiovascular, neurological and bone diseases), yet most of these studies have not taken full advantage of advanced andrological analysis. Altered proteostasis, i.e., the disbalance between protein synthesis and turnover, is a common denominator of many diseases, including but not limited to cancer and neurodegenerative diseases. This chapter introduces the concept of cellular proteostasis as a measure of sperm structural and functional integrity and an endpoint of varied impacts on spermiogenesis and sperm maturation, including heritability, general health, lifestyle, and occupational and environmental reprotoxic exposure. Special consideration is given to small molecule protein modifiers, sperm-binding seminal plasma proteins, zinc-interacting proteins, and redox proteins responsible for the maintenance of protein structure and the protection of spermatozoa from oxidative damage. While the main focus is on human male infertility, serious consideration is given to relevant animal models, and in particular to male food animals with extensive records of fertility from artificial insemination services. Altogether, the proteostatic biomarker discovery and validation studies set the stage for the integration of proteomics of sperm proteostasis with genomic and high throughput phenomic approaches to benefit both human and animal reproductive medicine.

• Keywords
• Biomarker, Infertility, Omics, Proteasome, Proteostasis, Seminal plasma, Sperm, Thioredoxin, Ubiquitin,
• MeSH
• Fertility * physiology   MeSH
• Proteostasis * physiology   MeSH
• Humans MeSH
• Infertility, Male * metabolism   genetics   pathology   physiopathology   MeSH
• Spermatogenesis * MeSH
• Spermatozoa * metabolism   pathology   physiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

(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.

• Keywords
• Huntington´s disease, KI-HD, TgHD, biomarker, exosome, extracellular vesicle, fragment, huntingtin, neurodegenerative disease, pig model,
• MeSH
• Biomarkers MeSH
• Extracellular Vesicles * metabolism   MeSH
• Huntington Disease * metabolism   MeSH
• Plasma metabolism   MeSH
• Humans MeSH
• Swine MeSH
• Nerve Tissue Proteins genetics   metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biomarkers MeSH
• Nerve Tissue Proteins 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.

• Keywords
• Minipigs, nonhuman primates, sheep, therapeutics,
• MeSH
• Animals, Genetically Modified * MeSH
• Huntington Disease * genetics   pathology   physiopathology   therapy   MeSH
• Swine, Miniature MeSH
• Disease Models, Animal * MeSH
• Sheep MeSH
• Swine MeSH
• Primates MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Huntington's disease (HD) is an inherited devastating neurodegenerative disease with no known cure to date. Several therapeutic treatments for HD are in development, but their safety, tolerability and efficacy need to be tested before translation to bedside. The monogenetic nature of this disorder has enabled the generation of transgenic animal models carrying a mutant huntingtin (mHTT) gene causing HD. A large animal model reflecting disease progression in humans would be beneficial for testing the potential therapeutic approaches. Progression of the motor, cognitive and behavioral phenotype was monitored in transgenic Huntington's disease minipigs (TgHD) expressing the N-terminal part of human mHTT. New tests were established to investigate physical activity by telemetry, and to explore the stress-induced behavioral and cognitive changes in minipigs. The longitudinal study revealed significant differences between 6- to 8-year-old TgHD animals and their wild-type (WT) controls in a majority of the tests. The telemetric study showed increased physical activity of 4.6- to 6.5-year-old TgHD boars compared to their WT counterparts during the lunch period as well as in the afternoon. Our phenotypic study indicates progression in adult TgHD minipigs and therefore this model could be suitable for longstanding preclinical studies of HD.This article has an associated First Person interview with the first author of the paper.

• Keywords
• Cognitive and behavioral studies, Huntington's disease, Large animal model, Motor, Phenotyping,
• MeSH
• Behavior, Animal physiology   MeSH
• Animals, Genetically Modified MeSH
• Huntington Disease complications   physiopathology   MeSH
• Tongue MeSH
• Cognition physiology   MeSH
• Physical Conditioning, Animal MeSH
• Longitudinal Studies MeSH
• Swine, Miniature MeSH
• Disease Models, Animal MeSH
• Motor Activity * MeSH
• Swine MeSH
• Stress, Psychological complications   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Recently developed therapeutic approaches for the treatment of Huntington's disease (HD) require preclinical testing in large animal models. The minipig is a suitable experimental animal because of its large gyrencephalic brain, body weight of 70-100 kg, long lifespan, and anatomical, physiological and metabolic resemblance to humans. The Libechov transgenic minipig model for HD (TgHD) has proven useful for proof of concept of developing new therapies. However, to evaluate the efficacy of different therapies on disease progression, a broader phenotypic characterization of the TgHD minipig is needed. In this study, we analyzed the brain tissues of TgHD minipigs at the age of 48 and 60-70 months, and compared them to wild-type animals. We were able to demonstrate not only an accumulation of different forms of mutant huntingtin (mHTT) in TgHD brain, but also pathological changes associated with cellular damage caused by mHTT. At 48 months, we detected pathological changes that included the demyelination of brain white matter, loss of function of striatal neurons in the putamen and activation of microglia. At 60-70 months, we found a clear marker of neurodegeneration: significant cell loss detected in the caudate nucleus, putamen and cortex. This was accompanied by clusters of structures accumulating in the neurites of some neurons, a sign of their degeneration that is also seen in Alzheimer's disease, and a significant activation of astrocytes. In summary, our data demonstrate age-dependent neuropathology with later onset of neurodegeneration in TgHD minipigs.

• Keywords
• Brain, Huntingtin, Large animal model, Neuropathology, TgHD,
• MeSH
• White Matter pathology   ultrastructure   MeSH
• Biomarkers metabolism   MeSH
• Nerve Degeneration pathology   MeSH
• Animals, Genetically Modified MeSH
• Genotype MeSH
• Weight Loss MeSH
• Huntington Disease pathology   MeSH
• Body Mass Index MeSH
• Humans MeSH
• Swine, Miniature MeSH
• Disease Models, Animal MeSH
• Motor Cortex pathology   ultrastructure   MeSH
• Myelin Sheath metabolism   MeSH
• Caudate Nucleus pathology   ultrastructure   MeSH
• Swine MeSH
• Huntingtin Protein metabolism   MeSH
• Protein Aggregates MeSH
• Aging pathology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biomarkers MeSH
• Htt protein, mouse MeSH Browser
• Huntingtin Protein MeSH
• Protein Aggregates MeSH

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.

• Keywords
• Biomarkers, Disease development, HD large animal model, Huntington's disease, Mitochondrial function, Skeletal muscle, Ultrastructure,
• MeSH
• DNA metabolism   MeSH
• Energy Metabolism * MeSH
• Animals, Genetically Modified MeSH
• Huntington Disease metabolism   pathology   MeSH
• Muscle, Skeletal metabolism   ultrastructure   MeSH
• Humans MeSH
• Swine, Miniature MeSH
• Mitochondrial Proteins metabolism   MeSH
• Disease Models, Animal * MeSH
• Mutation MeSH
• Oxidative Phosphorylation MeSH
• Swine MeSH
• Disease Progression MeSH
• Huntingtin Protein genetics   MeSH
• Mitochondria, Muscle metabolism   ultrastructure   MeSH
• Body Weight MeSH
• Electron Transport MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA MeSH
• HTT protein, human MeSH Browser
• Mitochondrial Proteins MeSH
• Huntingtin Protein MeSH