C. elegans Models to Study the Propagation of Prions and Prion-Like Proteins

A hallmark common to many age-related neurodegenerative diseases, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), is that patients develop proteinaceous deposits in their central nervous system (CNS). The progressive spreading of these inclusions from initially affected sites to interconnected brain areas is reminiscent of the behavior of bona fide prions in transmissible spongiform encephalopathies (TSEs), hence the term prion-like proteins has been coined. Despite intensive research, the exact mechanisms that facilitate the spreading of protein aggregation between cells, and the associated loss of neurons, remain poorly understood. As population demographics in many countries continue to shift to higher life expectancy, the incidence of neurodegenerative diseases is also rising. This represents a major challenge for healthcare systems and patients’ families, since patients require extensive support over several years and there is still no therapy to cure or stop these diseases. The model organism Caenorhabditis elegans offers unique opportunities to accelerate research and drug development due to its genetic amenability, its transparency, and the high degree of conservation of molecular pathways. Here, we will review how recent studies that utilize this soil dwelling nematode have proceeded to investigate the propagation and intercellular transmission of prions and prion-like proteins and discuss their relevance by comparing their findings to observations in other model systems and patients.

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Crosstalk between Different DNA Repair Pathways Contributes to Neurodegenerative Diseases

Biology ◽

10.3390/biology10020163 ◽

2021 ◽

Vol 10 (2) ◽

pp. 163

Author(s):

Swapnil Gupta ◽

Panpan You ◽

Tanima SenGupta ◽

Hilde Nilsen ◽

Kulbhushan Sharma

Keyword(s):

Dna Repair ◽

Neurodegenerative Diseases ◽

3D Models ◽

Model Systems ◽

Spinocerebellar Ataxias ◽

C Elegans ◽

Cellular Processes ◽

Age Related ◽

Damage Response ◽

Lateral Sclerosis

Genomic integrity is maintained by DNA repair and the DNA damage response (DDR). Defects in certain DNA repair genes give rise to many rare progressive neurodegenerative diseases (NDDs), such as ocular motor ataxia, Huntington disease (HD), and spinocerebellar ataxias (SCA). Dysregulation or dysfunction of DDR is also proposed to contribute to more common NDDs, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), and Amyotrophic Lateral Sclerosis (ALS). Here, we present mechanisms that link DDR with neurodegeneration in rare NDDs caused by defects in the DDR and discuss the relevance for more common age-related neurodegenerative diseases. Moreover, we highlight recent insight into the crosstalk between the DDR and other cellular processes known to be disturbed during NDDs. We compare the strengths and limitations of established model systems to model human NDDs, ranging from C. elegans and mouse models towards advanced stem cell-based 3D models.

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Sporadic Creutzfeldt-Jakob Disease and Other Proteinopathies in Comorbidity

Frontiers in Neurology ◽

10.3389/fneur.2020.596108 ◽

2020 ◽

Vol 11 ◽

Author(s):

Eva Parobkova ◽

Julie van der Zee ◽

Lubina Dillen ◽

Christine Van Broeckhoven ◽

Robert Rusina ◽

...

Keyword(s):

Neurodegenerative Diseases ◽

Prion Diseases ◽

Missense Variant ◽

Transmissible Spongiform Encephalopathies ◽

Disease Genes ◽

Systematic Analysis ◽

Spongiform Encephalopathies ◽

Variant Of Uncertain Significance ◽

Age Related ◽

Jakob Disease

Background: Sporadic Creutzfeldt–Jakob disease (sCJD) is the most common type of a group of transmissible spongiform encephalopathies (prion diseases). The etiology of the sporadic form of CJD is still unclear. sCJD can occur in combination with other neurodegenerative diseases, which further complicates the diagnosis. Alzheimer's disease (AD), e.g., is often seen in conjunction with sCJD.Method: In this study, we performed a systematic analysis of 15 genes related to the most important neurodegenerative diseases - AD, frontotemporal dementia, amyotrophic lateral sclerosis, prion disease, and Parkinson's disease - in a cohort of sCJD and sCJD in comorbidity with AD and primary age-related proteinopathy (PART). A total of 30 neuropathologically verified cases of sCJD with and without additional proteinopathies were included in the study. In addition, we compared microtubule-associated protein tau (MAPT) haplotypes between sCJD patients and patients with sCJD and PART or sCJD and AD. Then we studied the interaction between the Apolipoprotein E gene (APOE) and PRNP in sCJD patients.Results: We did not find any causal mutations in the neurodegenerative disease genes. We did detect a p.E318G missense variant of uncertain significance (VUS) in PSEN1 in three patients. In PRNP, we also found a previously described non-pathogenic insertion (p.P84_Q91Q).Conclusion: Our pilot study failed to find any critical differences between pure sCJD and sCJD in conjunction with other comorbid neurodegenerative diseases. Further investigations are needed to better understand this phenomenon.

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Graptopetalum paraguayense Extract Ameliorates Proteotoxicity in Aging and Age-Related Diseases in Model Systems

Nutrients ◽

10.3390/nu13124317 ◽

2021 ◽

Vol 13 (12) ◽

pp. 4317

Author(s):

Yan-Xi Chen ◽

Phuong Thu Nguyen Le ◽

Tsai-Teng Tzeng ◽

Thu-Ha Tran ◽

Anh Thuc Nguyen ◽

...

Keyword(s):

Model Systems ◽

Wild Type ◽

Nematode Caenorhabditis Elegans ◽

Cancer Cell Growth ◽

C Elegans ◽

Age Related ◽

Ampk Activity ◽

Β Amyloid ◽

Amp Activated Protein Kinase ◽

U87 Cells

Declines in physiological functions are the predominant risk factors for age-related diseases, such as cancers and neurodegenerative diseases. Therefore, delaying the aging process is believed to be beneficial in preventing the onset of age-related diseases. Previous studies have demonstrated that Graptopetalum paraguayense (GP) extract inhibits liver cancer cell growth and reduces the pathological phenotypes of Alzheimer’s disease (AD) in patient IPS-derived neurons. Here, we show that GP extract suppresses β-amyloid pathology in SH-SYS5Y-APP695 cells and APP/PS1 mice. Moreover, AMP-activated protein kinase (AMPK) activity is enhanced by GP extract in U87 cells and APP/PS1 mice. Intriguingly, GP extract enhances autophagy in SH-SYS5Y-APP695 cells, U87 cells, and the nematode Caenorhabditis elegans, suggesting a conserved molecular mechanism by which GP extract might regulate autophagy. In agreement with its role as an autophagy activator, GP extract markedly diminishes mobility decline in polyglutamine Q35 mutants and aged wild-type N2 animals in C. elegans. Furthermore, GP extract significantly extends lifespan in C. elegans.

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ESPO/ BIOLOGICAL SCIENCES SECTION SYMPOSIUM: EMERGING INSIGHTS IN INTERACTIONS AND NETWORKS IN THE BIOLOGY OF AGING DEVELOPING C. ELEGANS TO STUDY AGE-RELATED EXTRACELLULAR VESICLE SIGNALS

Innovation in Aging ◽

10.1093/geroni/igz038.1583 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

pp. S424-S424

Author(s):

Joshua Russell ◽

Matt Kaeberlein

Keyword(s):

Biological Sciences ◽

Mammalian Cell Culture ◽

Extracellular Vesicle ◽

Model Systems ◽

C Elegans ◽

Physiological Processes ◽

Age Related ◽

Powerful Approach ◽

Invertebrate Model ◽

Biology Of Aging

Abstract All cells release vesicles into their extracellular environment. These extracellular vesicles (EVs) contain multiple classes of molecules, including nucleic acids, proteins, and lipids. EV-signaling has been shown to be impacted by many age-related physiological processes such as inflammation, mitochondrial stress, and autophagy as well as directly mediate critical functions in cellular senescence and aging. The isolation and analysis of EV cargos from mammalian cell culture and liquid biopsy samples has become a powerful approach for uncovering the messages that are packaged into these organelles. Caenorhabditis elegans is a premier model for dissecting the genetics of aging however, EV analysis has not been tenable in invertebrate model systems due to lack of methods for obtaining sufficient amounts of pure EVs. We developed a method for isolating pure EVs from C. elegans with yields sufficient for mass spectrometry and RNAseq. Here we present the analysis of the genetic and protein cargos of EVs collected from wild type and long-lived mutants collected at different time points across their lifespans. As the first investigation of age-related EV signals in an invertebrate model system we believe these results will provide insights into cell non-autonomous mechanisms of aging.

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Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

Biomolecules ◽

10.3390/biom10030469 ◽

2020 ◽

Vol 10 (3) ◽

pp. 469

Author(s):

Hasier Eraña ◽

Jorge M. Charco ◽

Ezequiel González-Miranda ◽

Sandra García-Martínez ◽

Rafael López-Moreno ◽

...

Keyword(s):

Neurodegenerative Diseases ◽

Protein Misfolding ◽

Prion Diseases ◽

Immunohistochemical Analysis ◽

Body Fluids ◽

Detection Methods ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathies ◽

Prion Propagation

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrPSc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrPSc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrPSc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.

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Caenorhabditis elegans as a Model Organism to Evaluate the Antioxidant Effects of Phytochemicals

Molecules ◽

10.3390/molecules25143194 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3194

Author(s):

Begoña Ayuda-Durán ◽

Susana González-Manzano ◽

Ana M. González-Paramás ◽

Celestino Santos-Buelga

Keyword(s):

Oxidative Stress ◽

Caenorhabditis Elegans ◽

Model Organism ◽

Lipid Peroxides ◽

Biological Research ◽

Loss Of Function ◽

Fluorescent Reporters ◽

C Elegans ◽

High Degree

The nematode Caenorhabditis elegans was introduced as a model organism in biological research by Sydney Brenner in the 1970s. Since then, it has been increasingly used for investigating processes such as ageing, oxidative stress, neurodegeneration, or inflammation, for which there is a high degree of homology between C. elegans and human pathways, so that the worm offers promising possibilities to study mechanisms of action and effects of phytochemicals of foods and plants. In this paper, the genes and pathways regulating oxidative stress in C. elegans are discussed, as well as the methodological approaches used for their evaluation in the worm. In particular, the following aspects are reviewed: the use of stress assays, determination of chemical and biochemical markers (e.g., ROS, carbonylated proteins, lipid peroxides or altered DNA), influence on gene expression and the employment of mutant worm strains, either carrying loss-of-function mutations or fluorescent reporters, such as the GFP.

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Prion protein interconversions†

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2000.0765 ◽

2001 ◽

Vol 356 (1406) ◽

pp. 197-202 ◽

Cited By ~ 17

Author(s):

Byron Caughey

Keyword(s):

Neurodegenerative Diseases ◽

Prion Protein ◽

Prion Diseases ◽

Transmissible Spongiform Encephalopathies ◽

Biological Parameters ◽

Spongiform Encephalopathies ◽

Lead Compounds ◽

Resistant Form

The transmissible spongiform encephalopathies (TSEs), or prion diseases, remain mysterious neurodegenerative diseases that involve perturbations in prion protein (PrP) structure. This article summarizes our use of in vitro models to describe how PrP is converted to the disease–associated, protease–resistant form. These models reflect many important biological parameters of TSE diseases and have been used to identify inhibitors of the PrP conversion as lead compounds in the development of anti–TSE drugs.

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TSE Diagnostics: Recent Advances in Immunoassaying Prions

Clinical and Developmental Immunology ◽

10.1155/2013/360604 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

Anja Lukan ◽

Tanja Vranac ◽

Vladka Čurin Šerbec

Keyword(s):

Cerebrospinal Fluid ◽

Neurodegenerative Diseases ◽

Brain Tissue ◽

Prion Diseases ◽

Cellular Prion Protein ◽

Transmissible Spongiform Encephalopathies ◽

Post Mortem ◽

Definite Diagnosis ◽

Spongiform Encephalopathies ◽

Recent Advances

Transmissible spongiform encephalopathies (TSEs) or prion diseases are a group of rare fatal neurodegenerative diseases, affecting humans and animals. They are believed to be the consequence of the conversion of the cellular prion protein to its aggregation-prone,β-sheet-rich isoform, named prion. Definite diagnosis of TSEs is determinedpost mortem. For this purpose, immunoassays for analyzing brain tissue have been developed. However, the ultimate goal of TSE diagnostics is anante mortemtest, which would be sensitive enough to detect prions in body fluids, that is, in blood, cerebrospinal fluid, or urine. Such a test would be of paramount importance also for screening of asymptomatic carriers of the disease with the aim of increasing food, drugs, and blood-derived products safety. In the present paper, we have reviewed recent advances in the development of immunoassays for the detection of prions.

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Interaction of Neuromelanin with Xenobiotics and Consequences for Neurodegeneration; Promising Experimental Models

Antioxidants ◽

10.3390/antiox10060824 ◽

2021 ◽

Vol 10 (6) ◽

pp. 824

Author(s):

Andrea Capucciati ◽

Fabio A. Zucca ◽

Enrico Monzani ◽

Luigi Zecca ◽

Luigi Casella ◽

...

Keyword(s):

Animal Models ◽

Neurodegenerative Diseases ◽

Brain Aging ◽

Experimental Models ◽

Test Tube ◽

Age Related ◽

And Function ◽

Endogenous Metabolites ◽

High Degree

Neuromelanin (NM) accumulates in catecholamine long-lived brain neurons that are lost in neurodegenerative diseases. NM is a complex substance made of melanic, peptide and lipid components. NM formation is a natural protective process since toxic endogenous metabolites are removed during its formation and as it binds excess metals and xenobiotics. However, disturbances of NM synthesis and function could be toxic. Here, we review recent knowledge on NM formation, toxic mechanisms involving NM, go over NM binding substances and suggest experimental models that can help identifying xenobiotic modulators of NM formation or function. Given the high likelihood of a central NM role in age-related human neurodegenerative diseases such as Parkinson’s and Alzheimer’s, resembling such diseases using animal models that do not form NM to a high degree, e.g., mice or rats, may not be optimal. Rather, use of animal models (i.e., sheep and goats) that better resemble human brain aging in terms of NM formation, as well as using human NM forming stem cellbased in vitro (e.g., mid-brain organoids) models can be more suitable. Toxicants could also be identified during chemical synthesis of NM in the test tube.

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High-Content C. elegans Screen Identifies Natural Compounds Impacting Mitochondria-Lipid Homeostasis and Promoting Healthspan

Cells ◽

10.3390/cells11010100 ◽

2021 ◽

Vol 11 (1) ◽

pp. 100

Author(s):

Silvia Maglioni ◽

Nayna Arsalan ◽

Anna Hamacher ◽

Shiwa Afshar ◽

Alfonso Schiavi ◽

...

Keyword(s):

Stress Response ◽

Lipid Content ◽

Model Organism ◽

Natural Compounds ◽

Extrinsic Factors ◽

Mitochondrial Stress ◽

C Elegans ◽

Stress Response Genes ◽

Age Related ◽

Kahalalide F

The aging process is concurrently shaped by genetic and extrinsic factors. In this work, we screened a small library of natural compounds, many of marine origin, to identify novel possible anti-aging interventions in Caenorhabditis elegans, a powerful model organism for aging studies. To this aim, we exploited a high-content microscopy platform to search for interventions able to induce phenotypes associated with mild mitochondrial stress, which is known to promote animal’s health- and lifespan. Worms were initially exposed to three different concentrations of the drugs in liquid culture, in search of those affecting animal size and expression of mitochondrial stress response genes. This was followed by a validation step with nine compounds on solid media to refine compounds concentration, which led to the identification of four compounds (namely isobavachalcone, manzamine A, kahalalide F and lutein) consistently affecting development, fertility, size and lipid content of the nematodes. Treatment of Drosophila cells with the four hits confirmed their effects on mitochondria activity and lipid content. Out of these four, two were specifically chosen for analysis of age-related parameters, kahalalide F and lutein, which conferred increased resistance to heat and oxidative stress and extended animals’ healthspan. We also found that, out of different mitochondrial stress response genes, only the C. elegans ortholog of the synaptic regulatory proteins neuroligins, nlg-1, was consistently induced by the two compounds and mediated lutein healthspan effects.

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