Trending With Impact: Worms Reveal Early Event in Neurodegeneration

Researchers examined roundworms to determine the role of mitochondrial dysfunction in progressive neurodegenerative disorders, such as Alzheimer’s disease.

From Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae. (truncated)
From Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae. (truncated)

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Many aging-associated neurodegenerative disorders, including Alzheimer’s disease, involve the aggregation of abnormal tau in nerve cells (neurons). Normally, tau proteins function to stabilize microtubules in the brain. Tauopathy occurs when tau proteins become misfolded and misshapen (which turns tau into toxic tau). They then continue to proliferate and bind to each other, forming tau oligomers. These tau oligomers are more toxic and have a greater potential to spread tau pathology. Before the tau pathology snowballs into neurodegenerative disorders, the events that lead up to abnormal tau have remained elusive to researchers. 

“While the association between tau levels and energy metabolism is established, it is not clear whether mitochondrial dysfunction is an early pathological feature of high levels of tau or a consequence of its excessive formation of protein aggregates.”

Previous studies have demonstrated an association between tau levels and mitochondrial metabolism, however, determining which one proceeds the other has yet to be fully illuminated. Shedding light on this subject, researchers—from the University of CopenhagenNational and Kapodistrian University of Athens and the National Institutes of Health’s National Institute on Aging—used a Caenorhabditis elegans (C. elegans; roundworm/nematode) model of tau to examine mitochondrial changes over time. Their paper was chosen as the cover of Aging (Aging-US) Volume 13, Issue 21, published in November of 2021 and entitled, “Alteration of mitochondrial homeostasis is an early event in a C. elegans model of human tauopathy”.  

The Study

“Here, we utilized transgenic nematodes expressing the full length of wild type tau in neuronal cells and monitored mitochondrial morphology alterations over time.”

To investigate the impact of tau on mitochondrial activity, neuronal function and organismal physiology, the researchers selected and cultured an already characterized nematode strain that expresses the full length of wild type human tau protein. They compared wild type nematodes with tau-expressing nematodes (at various ages) over time using a thrashing assay, mitochondrial imaging, worm tracking software, and western blot analysis. Calcium deregulation was also examined to determine whether or not it is implicated in the impairment of mitochondrial activity in the tau-expressing nematodes. They found that chelating calcium led to restored mitochondrial activity and suggested a link between mitochondrial damage, calcium homeostasis and neuronal impairment in this nematode model.

Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae.
Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae.

Conclusion

“Our findings suggest that defective mitochondrial function is an early pathogenic event of tauopathies, taking place before tau aggregation and undermining neuronal homeostasis and organismal fitness.”

The researchers were forthcoming about limitations in their study, given the differences between human and nematode biology and pathology. Nevertheless, they found evidence that, in this nematode tauopathy model, neurotoxicity depends on protein alterations and mitochondrial dysfunction. Mitochondrial dysfunction takes place before high levels of tau are detected. Tau mutations may also modulate calcium homeostasis by influencing the main cellular storage sites—the endoplasmic reticulum and mitochondria.

“Investigating the tight interplay between tau oligomers and energy metabolism will enlighten new avenues for therapeutic strategies to slow or halt the progression of dementia-related diseases such as AD [Alzheimer’s disease].”

Click here to read the full priority research paper published by Aging (Aging-US).

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Aging (Aging-US) is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Trending With Impact: Retired Sled Dogs in Aging Research

Researchers adopted 103 retired sled dogs for a longitudinal study on canine aging that may one day be used to increase human healthspan and longevity.

sled dogs

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Whether they are sprinters or distance runners, sled dogs are known for their competitive nature and athletic prowess. With age, however, these athletes eventually run out of steam—just as humans inevitably do. Canines of all breeds are affected by aging, including a loss of resilience, accumulation of molecular damage and age-related diseases. These relatively short-lived, large mammals are one of the few to share environments with humans, and even have access to advanced medical care. Many believe the canine aging process resembles human aging the closest compared to any other animal. 

A team of scientists—from Cornell UniversityNorth Carolina State UniversityTauber Bioinformatic Research Center, and Roswell Park Comprehensive Cancer Center—saw the opportunities and advantages of studying canine aging in a controlled environment. Co-founders Andrei Gudkov, PhD, Dr Sci, Katerina Andrianova, PhD, and Daria Fleyshman, PhD, established a non-profit organization called Vaika Inc. In 2018, Vaika allowed these researchers to begin collaborating in a longitudinal study on the mechanisms of aging among 103 retired sled dogs. The researchers authored a trending research perspective about the details of their long-term study. In September 2021, their paper was published on the cover of Aging (Aging-US)’s Volume 13, Issue 18, and entitled, “Development of infrastructure for a systemic multidisciplinary approach to study aging in retired sled dogs.”

THE STUDY

The researchers chose to adopt retired sled dogs for this study in particular for a variety of reasons: 1) Based on the type of events they partake in, sled dogs usually have a record of health and performance that can be used for reference as they age. 2) Sled dogs are selected for performance, but are not limited to a particular breed and can be crossbred. This provides a somewhat homogeneous population to study while being less prone to breed-specific biases. 3) Sled dogs are used to working with many handlers, therefore, the transition into the kennel/research facility may be easier for them to adjust to. 4) Over their career, these dogs have been exposed to environmental pathogens in frequent group interactions. This provides the researchers a sufficient immune system model to study. 5) Sled dogs are used to living in packs, but forming short-term bonds—making them adaptable to living with a variety of handlers in a population of 103 other dogs. 

“Thus, it is essential to establish a reference set of ‘healthy aging’ parameters specifically for each dog model, and we see this as one of the main goals of our sled dog study.”

The optics of caring for 103 retired sled dogs between the ages of eight and 11 (when the study began) may initially sound problematic, but all indications suggest that these dogs are living better than many humans. Their 8,254-square foot kennel is located on the Baker Institute campus of the College of Veterinary Medicine at Cornell University. The researchers designed the study so that the dogs are thoroughly examined, observed, fed, socialized, exercised, vaccinated and anything else they may need. The dogs’ personalities and special needs are taken into consideration when cohabitating with other dogs, in their separate rooms and during playtime outside. They have in-house veterinarians and researchers to monitor their health. Importantly, the researchers are monitoring not only the dogs’ health but also parameters of their individual aging experience.

“Our goal is not just to assess the state of health of a given dog but rather to dissect the aging process into its two key components: (i) declining resilience and (ii) acquisition of aging-related diseases.”

In order to observe declining resilience and aging-related diseases, the dogs participate in regular physical fitness (treadmill and pull tests) and cognitive tests (handler questionnaires, β-amyloid plaques, brain atrophy, neuron loss, and etc.). Their performance and scores are measured and compared to their previous scores. The researchers also regularly collect blood samples to assess the dogs for somatic cell genome modifications (accumulation of DNA damage) and immune system status (immunosenescence).

“In general, the canine immune system undergoes similar age-related changes to that of humans [85]. However, since completed canine studies are generally less comprehensive and predominantly cross-sectional, the reliability and relative significance of various immune parameters in aging have yet to be characterized.”

CONCLUSION

This research is still ongoing, and the researchers believe the infrastructure they established in this sled dog study is an important advancement in aging research. In the future, this animal model may be used to test anti-aging therapies and translate into advancing human healthspan and lifespan.

“We expect that these analyses will allow us to (i) characterize the mechanism(s) and regulation of canine aging, (ii) identify parameters and biomarkers suitable for assessment of biological age, and (iii) define factors that may act as aging accelerators or decelerators.”

Click here to read the full research perspective, published by Aging (Aging-US).

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Aging (Aging-US) is an open-access journal that publishes research papers twice a month—in all fields of aging research and other biomedical topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Aging Testimonial: Dr. Kara Fitzgerald

Below is a transcript of the testimonial by Dr. Kara Fitzgerald, from the Institute for Functional Medicine in Federal Way, Washington, about her experience publishing the paper, “Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial,” with Aging.

Researchers explain their studies that were published in Aging
Researchers explain their studies that were published in Aging
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Dr. Kara Fitzgerald:

I am thrilled with our study being accepted into the journal Aging. I think it’s the perfect home for it.

The process of submitting and our peer review journey was actually, it was actually a lot of fun! I found our peer reviewers, they really move our study forward and help us to articulate our findings and inquisitive, appreciative of what we’ve done. And so that whole piece of it was good.

Dr. David Sinclair actually suggested that Aging would be the right home for us and I couldn’t agree more.

What else? It’s open access. I think open access is essential. Having our study behind a paywall and inaccessible to other scientists and just the community who might be interested in the longevity research that’s happening, particularly this, which is a diet and lifestyle program so, it’s something that people could actually do if they wanted to. We want that available. So I’m all for open access.

I enjoyed working with Aging. I thought that they were good across the board. And I just appreciate David’s recommendation that we go here.

Click here to read the full study published by Aging.

Click the links below for more information on corresponding author, Dr. Kara Fitzgerald:
Biological Aging Summary | Instagram | Facebook | Twitter | General Site | Younger You Program

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Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

Trending With Impact: New Drug Combinations Inhibit Stress Proteins

Researchers tested antiviral, anticancer, and immunosuppressive drug combinations that may aid in treating neurodegenerative disorders, including Alzheimer’s disease.

Figure 5. Neratinib and AR12 combine to reduce the expression of HSP90, HSP70, GRP78 and HSP27 via autophagy.
Figure 5. Neratinib and AR12 combine to reduce the expression of HSP90, HSP70, GRP78 and HSP27 via autophagy.

The Trending with Impact series highlights Aging publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Heat shock proteins (HSPs), also known today as stress proteins, were first observed in fruit flies in the 1960s. After Dr. Ferruccio Ritossa inadvertently subjected a preparation of fruit fly salivary glands to a non-lethal increase in temperature, he discovered a new pattern of chromosomal “puffing.” In 1974, researchers identified the proteins that were encoded by the “puffs” recorded by Dr. Ritossa, and named them heat shock proteins. 

These newfound proteins appeared to only become detectable when the cells were heated. Researchers later learned that HSPs can also be induced by oxidants, toxins, heavy metals, free radicals, viruses, and other stressors. Since its discovery, variations of this genetic system have been found in all bacteria, plants, and animals—including humans. HSPs have been well-studied since this revelation, and researchers now believe these molecular chaperones play important roles in protein refolding, aging-related diseases, and overall longevity. 

“Toxic misfolded proteins are key drivers of AD [Alzheimer’s disease], ALS [Amyotrophic lateral sclerosis], HC [Huntington’s Chorea] and other neurodegenerative diseases.”

Researchers from Virginia Commonwealth UniversityTranslational Genomics Research Institute, and the Banner Alzheimer’s Institute took part in a research study experimenting with combinations of therapeutic agents that may improve neurodegenerative diseases. In 2021, their paper was published in Aging’s Volume 13, Issue 13, and entitled, “Inhibition of heat shock proteins increases autophagosome formation, and reduces the expression of APP, Tau, SOD1 G93A and TDP-43.”

“In this paper we examined using isogenic colon cancer cells [with] several existing drugs that function by increasing autophagy and degrading misfolded proteins.”

THE STUDY

“Aberrant expression of chaperone proteins is found in many human pathologies including cancer, in virology and in AD, ALS and HC.”

In this study, researchers tested drugs that have been used preclinically and clinically in several anticancer studies. The drugs used were: AR12, an antiviral chaperone ATPase inhibitor; Neratinib, a tyrosine kinase inhibitor; a combination of AR12 and Neratinib; Fingolimod, an immunosuppressive sphingosine l-phosphate receptor modulator; MMF, monomethyl fumarate; and a combination of Fingolimod and MMF.

The cells they tested these drug combinations on in vitro included Vero cells (African Green Monkey kidney cells), isogenic HCT116 colon cancer cells (genetically manipulated colon cancer cells), and GB6 cells (glioblastoma cancer stem cells). They also used plasmids, antibodies, and siRNAs. Researchers acknowledged that the use of non-neuronal cells may be a limitation of this study.

“Our present studies were performed in non-neuronal cells and as a caveat, it is possible that our data in HCT116 and Vero cells will not be reflective of the same processes in neuronal cells.”

Despite this caveat, results from their research were promising. Some combinations of these drugs were capable of knocking down many disease specific proteins that form toxic aggregates inside cells and in extracellular environments via autophagy. 

CONCLUSION

“As the mechanism of drug-action became clearer it was apparent that these agents should also be tested in neurodegenerative diseases. The entire neurodegenerative field needs rapid translational methods that target the underlying cause of disease, toxic misfolded protein. The findings from this work warrant further testing with a focus on clinical utility.”

Click here to read the full research paper, published by Aging.

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Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.


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Behind the Study: Cdkn1a Transcript and Aging

Dr. Judith Campisi discusses her priority research paper published in 2021 by Aging, entitled, “Cdkn1a transcript variant 2 is a marker of aging and cellular senescence.”

Researchers explain their studies that were published in Aging

Behind the Study is a series of transcribed videos from researchers elaborating on their recent oncology-focused studies published by Aging. A new Behind the Study is released each Monday. Visit the Aging YouTube channel for more insights from outstanding authors.

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Hello, my name is Judy Campisi. I am a Professor at the Buck Institute for Research on Aging and also a Senior Scientist at the Lawrence Berkeley National Lab. And my laboratory, which is a pretty international laboratory with people from Asia and Europe, published a paper in aging, “Cdkn1a transcript variant 2 is a marker of aging and cellular senescence.”

So why do we care about this?

Well, most of my lab works on a process called cellular senescence, which is a cellular response to stresses and damage, many of which increase with age. And it’s now clear from mouse models that if you eliminate senescent cells, which increase with age, you can increase the health span of a mouse – not necessarily the lifespan, but the health span. So it becomes kind of important to have ways of identifying senescent cells in detail, and we have not been able to do that so far with absolute certainty because there frankly are no senescent-specific markers. So there are markers that are commonly expressed by senescent cells, but none of them are absolutely specific.

Figure 1. The Cdkn1a variant 2 transcript is preferentially induced during aging.
Figure 1. The Cdkn1a variant 2 transcript is preferentially induced during aging.

And so what we have done is we have looked at one of those markers, which is a gene called Cdkn1a and it codes for approaching, called P21. So everyone knows that P21 is one of those common biomarkers of aging, but it also is not necessarily strictly limited to aging. And what we’ve found is that there are two mRNAs that are made from that gene, that had been known before. We looked at these two mRNAs separately and found that one of them, which is called the variant 2, is a better marker of senescence and aging than the other mRNA. And that gives us a little bit of a edge in trying to unambiguously identify senescent cells in vivo and even in culture.

So the importance of this work is that it helps refine our ways of identifying these cells. We now know that these cells are important in aging, certainly in mice, probably in humans as well. So with this group of mine, many of which come from Spain or France or Russia, many of them contributed to refining this marker and allowing us to be able to have a better way of having some confidence that a senescent cell is indeed senescence.

And I can stop here.

Click here to read the full study published by Aging.

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Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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