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

Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 100
Author(s):  
Silvia Maglioni ◽  
Nayna Arsalan ◽  
Anna Hamacher ◽  
Shiwa Afshar ◽  
Alfonso Schiavi ◽  
...  

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.

Author(s):  
Sanjib Guha ◽  
Sarah Fischer ◽  
Gail VW Johnson ◽  
Keith Nehrke

ABSTRACTBackgroundA defining pathological hallmark of the progressive neurodegenerative disorder Alzheimer’s disease (AD) is the accumulation of misfolded tau with abnormal post-translational modifications (PTMs). These include phosphorylation at Threonine 231 (T231) and acetylation at Lysine 274 (K274) and at Lysine 281 (K281). Although tau is recognized to play a central role in pathogenesis of AD, the precise mechanisms by which these abnormal PTMs contribute to the neural toxicity of tau is unclear.MethodsHuman 0N4R tau (wild type) was expressed in touch receptor neurons of the genetic model organism C. elegans through single-copy gene insertion. Defined mutations were then introduced into the single-copy tau transgene through CRISPR-Cas9 genome editing. These mutations included T231E and T231A, to mimic phosphorylation and phospho-ablation of a commonly observed pathological epitope, respectively, and K274/281Q, to mimic disease-associated lysine acetylation. Stereotypical touch response assays were used to assess behavioral defects in the transgenic strains as a function of age, and genetically-encoded fluorescent biosensors were used to measure the morphological dynamics and turnover of touch neuron mitochondria.ResultsUnlike existing tau overexpression models, C. elegans single-copy expression of tau did not elicit overt pathological phenotypes at baseline. However, strains expressing disease associated PTM-mimetics (T231E and K274/281Q) exhibited reduced touch sensation and morphological abnormalities that increased with age. In addition, the PTM-mimetic mutants lacked the ability to engage mitophagy in response to mitochondrial stress.ConclusionsLimiting the expression of tau results in a genetic model where pathological modifications and age result in evolving phenotypes, which may more closely resemble the normal progression of AD. The finding that disease-associated PTMs suppress compensatory responses to mitochondrial stress provides a new perspective into the pathogenic mechanisms underlying AD.


2020 ◽  
Vol 55 (S1) ◽  
pp. 89-105

Cell volume is one of the most aggressively defended physiological set points in biology. Changes in intracellular ion and water concentrations, which are induced by changes in metabolism or environmental exposures, disrupt protein folding, enzymatic activity, and macromolecular assemblies. To counter these challenges, cells and organisms have evolved multifaceted, evolutionarily conserved molecular mechanisms to restore cell volume and repair stress induced damage. However, many unanswered questions remain regarding the nature of cell volume 'sensing' as well as the molecular signaling pathways involved in activating physiological response mechanisms. Unbiased genetic screening in the model organism C. elegans is providing new and unexpected insights into these questions, particularly questions relating to the hypertonic stress response (HTSR) pathway. One surprising characteristic of the HTSR pathway in C. elegans is that it is under strong negative regulation by proteins involved in protein homeostasis and the extracellular matrix (ECM). The role of the ECM in particular highlights the importance of studying the HTSR in the context of a live organism where native ECM-tissue associations are preserved. A second novel and recently discovered characteristic is that the HTSR is regulated at the post-transcriptional level. The goal of this review is to describe these discoveries, to provide context for their implications, and to raise outstanding questions to guide future research.


2010 ◽  
Vol 45 (7-8) ◽  
pp. 550-557 ◽  
Author(s):  
Alessandro Torgovnick ◽  
Alfonso Schiavi ◽  
Roberto Testi ◽  
Natascia Ventura

Biomolecules ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1188 ◽  
Author(s):  
Carl Alexander Sandhof ◽  
Simon Oliver Hoppe ◽  
Jessica Tittelmeier ◽  
Carmen Nussbaum-Krammer

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.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
H. B. Atakan ◽  
K. S. Hof ◽  
M. Cornaglia ◽  
J. Auwerx ◽  
M. A. M. Gijs

AbstractFluctuations and deterioration in environmental conditions potentially have a phenotypic impact that extends over generations. Transgenerational epigenetics is the defined term for such intergenerational transient inheritance without an alteration in the DNA sequence. The model organism Caenorhabditis elegans is exceptionally valuable to address transgenerational epigenetics due to its short lifespan, well-mapped genome and hermaphrodite behavior. While the majority of the transgenerational epigenetics on the nematodes focuses on generations-wide heritage, short-term and in-depth analysis of this phenomenon in a well-controlled manner has been lacking. Here, we present a novel microfluidic platform to observe mother-to-progeny heritable transmission in C. elegans at high imaging resolution, under significant automation, and enabling parallelized studies. After approximately 24 hours of culture of L4 larvae under various concentrations and application periods of doxycycline, we investigated if mitochondrial stress was transferred from the mother nematodes to the early progenies. Automated and custom phenotyping algorithms revealed that a minimum doxycycline concentration of 30 µg/mL and a drug exposure time of 15 hours applied to the mothers could induce mitochondrial stress in first embryo progenies indeed, while this inheritance was not clearly observed later in L1 progenies. We believe that our new device could find further usage in transgenerational epigenetic studies modeled on C. elegans.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Sanjib Guha ◽  
Sarah Fischer ◽  
Gail V. W. Johnson ◽  
Keith Nehrke

Abstract Background A defining pathological hallmark of the progressive neurodegenerative disorder Alzheimer’s disease (AD) is the accumulation of misfolded tau with abnormal post-translational modifications (PTMs). These include phosphorylation at Threonine 231 (T231) and acetylation at Lysine 274 (K274) and at Lysine 281 (K281). Although tau is recognized to play a central role in pathogenesis of AD, the precise mechanisms by which these abnormal PTMs contribute to the neural toxicity of tau is unclear. Methods Human 0N4R tau (wild type) was expressed in touch receptor neurons of the genetic model organism C. elegans through single-copy gene insertion. Defined mutations were then introduced into the single-copy tau transgene through CRISPR-Cas9 genome editing. These mutations included T231E, to mimic phosphorylation of a commonly observed pathological epitope, and K274/281Q, to mimic disease-associated lysine acetylation – collectively referred as “PTM-mimetics” – as well as a T231A phosphoablation mutant. Stereotypical touch response assays were used to assess behavioral defects in the transgenic strains as a function of age. Genetically-encoded fluorescent biosensors were expressed in touch neurons and used to measure neuronal morphology, mitochondrial morphology, mitophagy, and macro autophagy. Results Unlike existing tau overexpression models, C. elegans single-copy expression of tau did not elicit overt pathological phenotypes at baseline. However, strains expressing disease associated PTM-mimetics (T231E and K274/281Q) exhibited reduced touch sensation and neuronal morphological abnormalities that increased with age. In addition, the PTM-mimetic mutants lacked the ability to engage neuronal mitophagy in response to mitochondrial stress. Conclusions Limiting the expression of tau results in a genetic model where modifications that mimic pathologic tauopathy-associated PTMs contribute to cryptic, stress-inducible phenotypes that evolve with age. These findings and their relationship to mitochondrial stress provides a new perspective into the pathogenic mechanisms underlying AD.


2005 ◽  
Vol 9 (5) ◽  
pp. 605-615 ◽  
Author(s):  
Mohan Viswanathan ◽  
Stuart K. Kim ◽  
Ala Berdichevsky ◽  
Leonard Guarente

2017 ◽  
Author(s):  
Sarah M. Chang ◽  
Melanie R. McReynolds ◽  
Wendy Hanna-Rose

ABSTRACTMitochondrial sirtuins regulate biochemical pathways and are emerging drug targets for metabolic and age-related diseases such as cancer, diabetes, and neurodegeneration. Yet, their functions remain unclear. Here, we uncover a novel physiological role for the C. elegans mitochondrial sirtuins, sir-2.2 and sir-2.3, in lifespan regulation. Using a genetic approach, we demonstrate that sir-2.2 and sir-2.3 mutants live 28-30% longer than controls when fed the normal lab diet of E. coli OP50. Interestingly, this effect is diet specific and is not observed when animals are fed the strain HT115, which is typically used for RNAi experiments. While decreased consumption of food is a known mechanism for lifespan extension, this does not account for the increased lifespan in the mitochondrial sirtuin mutants. sir-2.2 and sir-2.3 mutants display altered expression of genes involved in oxidative stress response, including increased expression of the mitochondrial superoxide dismutase sod-3 and decreased levels of catalases ctl-1 and ctl-2. Like their extended lifespan phenotype, these alterations in oxidative stress gene expression are diet dependent. The mitochondrial sirtuin mutants are more resistant to the lifespan extending effects of low levels of superoxide, suggesting that their increased lifespan involves a hormetic response. Our data suggest that sir-2.2 and sir-2.3 are not completely redundant in function and may possess overlapping yet distinct mechanisms for regulating oxidative stress response and lifespan.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 121-122
Author(s):  
Marjana Sarker ◽  
Scott Leiser

Abstract Recent studies support the deterioration of the sense of smell as an important biomarker for cognitive impairment diseases, including Alzheimer’s disease. The model organism C. elegans has a well-studied olfactory system, which provides an ideal platform to measure loss of smell with aging. The goal of our project is to use the short lifespan and olfactory changes observed in nematodes to identify mechanisms to slow aging and treat age-related diseases. Our approach is to utilize worms at various times of their healthy adult lifespan and to test for their sensitivity to known attractants such as benzaldehyde. These odorants are largely detected by the main AWC olfactory neurons. It is well documented that the responsiveness of AWC decreases with age. Our paradigm is to briefly fast worms to increase motivation before testing their ability to discriminate odors. Our results show that younger worms actively move toward the attractant and show preference for specific attractants. However, older worms frequently do not respond to attractive odors and remain near the point of origin, regardless of motility. These results indicate a decreased odor response with age. Our current work focuses on identifying genes and compounds that positively affect this odor response in older animals. The resulting data can then be tested for their efficacy to improve other aspects of healthspan and potentially longevity.


2018 ◽  
Vol 24 (19) ◽  
pp. 2107-2120 ◽  
Author(s):  
Nikoletta Papaevgeniou ◽  
Niki Chondrogianni

Polyphenols constitute a group of compounds that have been highly investigated for their beneficial effects against various pathologic and non-pathologic conditions and diseases. Among their multi-faceted properties, their anti-oxidant potential nominates them as ideal protective candidates for conditions characterized by elevated levels of oxidative stress, including aging and age-related diseases. The nematode Caenorhabditis elegans is a multicellular model organism that is highly exploited in studies related to aging and age-associated pathologies. In this review, we will summarize studies where polyphenolic compounds have been tested for their anti-aging potential and their protective role against the progression of age-related diseases using C. elegans as their main model.


Sign in / Sign up

Export Citation Format

Share Document