การใช้ C. elegans เป็นโมเดลเพื่อศึกษาโรคอัลไซเมอร์ Using C. elegans as A Model for the Study of Alzheimer’s Disease

บทคัดย่อCaenorhabditis elegans (C. elegans) ซึ

Neuroprotective effects and mechanism of cognitive-enhancing choline analogs JWB 1-84-1 and JAY 2-22-33 in neuronal culture and Caenorhabditis elegans

<p>Abstract</p> <p>Background</p> <p>Our previous work indicated that novel analogs of choline have cytoprotective effects <it>in vitro </it>that might be useful in neurodegenerative conditions such as Alzheimer's disease (AD). Furthermore, two lead compounds (JWB1-84-1 and JAY2-22-33) from a library of more than 50 improved cognitive performances in a transgenic mouse model of AD. The purpose of these experiments was to more specifically investigate the neuroprotective capabilities of these lead compounds both <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p>We used N2a cells which express a Swedish mutation in the amyloid precursor protein and presenilin 1 genes to investigate the effect of JWB1-84-1 and JAY2-22-33 on β-amyloid (Aβ) levels and found that both compounds significantly reduced Aβ levels. JWB1-84-1 and JAY2-22-33 also protected rat primary cortical neurons from Aβ toxicity. Subsequently, we utilized the nematode <it>Caenorhabditis elegans </it>(<it>C. elegans</it>) as an <it>in vivo </it>model organism to identify potential molecular targets of these compounds. In the <it>C. elegans </it>model of Aβ toxicity, human Aβ is expressed intracellularly in the body wall muscle. The expression and subsequent aggregation of Aβ in the muscle leads to progressive paralysis.</p> <p>Conclusion</p> <p>We found that JAY2-22-33 (but not JWB1-84-1) significantly reduced Aβ toxicity by delaying paralysis and this protective effect required both the insulin signaling pathway and nicotinic acetylcholine receptors (nAChRs).</p

The ethics of elective psychopharmacology

Pharmacological cognitive enhancers (PCEs) are used to improve cognitive functions, such as attention, learning, memory and planning in patients with impairments in cognition resulting from traumatic brain injury (TBI) or from neuropsychiatric disorders such as Alzheimer's disease (AD), mild cognitive impairment, schizophrenia, and attention deficit hyperactivity disorder (ADHD). Moreover, PCEs have been shown to improve cognition in healthy volunteers with no psychiatric disorders. This article describes the rationale behind the need for their use in neuropsychiatric patients and illustrates how PCEs can ameliorate cognitive impairments, improve quality of life and wellbeing, and therefore reduce the economic burden associated with these disorders. We also describe evidence that PCEs are being used as cognitive enhancers by healthy people. Crucially, as the lifestyle use of these drugs becomes very popular in the healthy population, a final aim is to present an overview of the current and future neuroethical considerations of enhancing the healthy brain. As information regarding their actual use, benefits and harms in various healthy populations is currently lacking, we propose research that aims to obtain relevant empirical data, monitor the short- and long-term effectiveness and side-effects, and initiate accurate surveys to determine current patterns and quantity of usage of PCE drugs by healthy people. Furthermore, in order to instigate a dialogue between neuroethics and neuropsychopharmacology, we urge scientists to explore and communicate the social and ethical implications of their research to the public. Finally, we discuss and highlight other means of enhancing cognition in both patients and healthy adults, including education and physical exercise

Monascus-Fermented Dioscorea Enhances Oxidative Stress Resistance via DAF-16/FOXO in Caenorhabditis elegans

BACKGROUND: Monascus-fermented products are mentioned in an ancient Chinese pharmacopoeia of medicinal food and herbs. Monascus-fermented products offer valuable therapeutic benefits and have been extensively used in East Asia for several centuries. Several biological activities of Monascus-fermented products were recently described, and the extract of Monascus-fermented products showed strong antioxidant activity of scavenging DPPH radicals. To evaluate whether Monascus-fermented dioscorea products have potential as nutritional supplements, Monascus-fermented dioscorea's modulation of oxidative-stress resistance and associated regulatory mechanisms in Caenorhabditis elegans were investigated. PRINCIPAL FINDINGS: We examined oxidative stress resistance of the ethanol extract of red mold dioscorea (RMDE) in C. elegans, and found that RMDE-treated wild-type C. elegans showed an increased survival during juglone-induced oxidative stress compared to untreated controls, whereas the antioxidant phenotype was absent from a daf-16 mutant. In addition, the RMDE reduced the level of intracellular reactive oxygen species in C. elegans. Finally, the RMDE affected the subcellular distribution of the FOXO transcription factor, DAF-16, in C. elegans and induced the expression of the sod-3 antioxidative gene. CONCLUSIONS: These findings suggest that the RMDE acts as an antioxidative stress agent and thus may have potential as a nutritional supplement. Further studies in C. elegans suggest that the antioxidant effect of RMDE is mediated via regulation of the DAF-16/FOXO-dependent pathway

Using C. elegans to discover therapeutic compounds for ageing-associated neurodegenerative diseases

Age-associated neurodegenerative disorders such as Alzheimer’s disease are a major public health challenge, due to the demographic increase in the proportion of older individuals in society. However, the relatively few currently approved drugs for these conditions provide only symptomatic relief. A major goal of neurodegeneration research is therefore to identify potential new therapeutic compounds that can slow or even reverse disease progression, either by impacting directly on the neurodegenerative process or by activating endogenous physiological neuroprotective mechanisms that decline with ageing. This requires model systems that can recapitulate key features of human neurodegenerative diseases that are also amenable to compound screening approaches. Mammalian models are very powerful, but are prohibitively expensive for high-throughput drug screens. Given the highly conserved neurological pathways between mammals and invertebrates, Caenorhabditis elegans has emerged as a powerful tool for neuroprotective compound screening. Here we describe how C. elegans has been used to model various human ageing-associated neurodegenerative diseases and provide an extensive list of compounds that have therapeutic activity in these worm models and so may have translational potential