How does protein homeostasis relate to aging?

As organisms age, proteins tend to lose their proper three-dimensional shape and become insoluble or misfolded. This process affects hundreds of proteins, some of which are critical for lifespan, suggesting a direct link between protein instability and aging.

What is hormetic stress and how can it benefit aging?

Hormetic stress involves exposing organisms to mild, transient challenges (like heat shock or fasting) that activate protective cellular pathways. These pathways, including those that help maintain protein structure, increase antioxidant capacity, and enhance autophagy, can help the body better cope with the stresses of aging.

What are the health benefits of sauna use related to aging?

Regular sauna use has been linked to lower all-cause mortality and a reduced risk of Alzheimer's disease. The heat exposure likely activates heat shock proteins and other stress response mechanisms, similar to observed benefits in model organisms.

How does excess dietary iron affect aging?

Excess iron can accelerate aging by damaging mitochondria and promoting the accumulation of insoluble proteins. Conversely, using iron chelators can extend lifespan and protect against protein aggregation in aging worms.

What is the link between Vitamin D deficiency and accelerated aging?

Vitamin D deficiency is associated with an increased risk of various chronic diseases, including cancers and neurological disorders. Research suggests Vitamin D may play a role in preventing protein insolubility and activating endogenous defense systems, potentially acting as a key regulator of the aging process.

How are new longevity compounds discovered using worms?

Researchers use the speed and genetic diversity of C. elegans to test numerous compounds for their ability to extend lifespan. Promising candidates found in worms are then considered for more expensive studies in mice, aiming to accelerate the discovery of effective longevity interventions.

Should I supplement with Vitamin D?

While Vitamin D can be beneficial, it's recommended to get your levels measured by a physician before starting supplementation. This helps determine an appropriate dosage and avoid potential risks associated with excessive intake or mineralization.

Gordon Lithgow, Ph.D. on Protein Aggregation, Iron Overload & the Search for Longevity Compounds

FoundMyFitness

Education4 min read44 min video

Apr 5, 2017|74,546 views|1,329|128

Rhonda Patrick Protein Aggregation iron overload longevity compounds amyloid beta plaques heat stress hormesis vitamin d receptor Buck Institute for Aging c. elegans lifespan extension heat shock proteins

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Key Moments

TL;DR

Dr. Gordon Lithgow discusses using worms to study aging, focusing on protein aggregation, heat shock, and vitamin D's role in longevity.

Key Insights

C. elegans worms are a valuable model for aging research due to their short lifespan and transparency, allowing for rapid and cost-effective compound screening.

Protein misfolding and aggregation are key contributors to the aging process, linking normal aging to age-related diseases like Alzheimer's and Parkinson's.

Hormetic stressors, such as heat shock and fasting, activate cellular defense mechanisms (like heat shock proteins and autophagy) that can extend lifespan.

Sauna use in humans is associated with reduced all-cause mortality and a significantly lower risk of developing Alzheimer's disease.

Elevated iron levels can accelerate aging and protein aggregation, while iron chelation can extend lifespan and protect against these processes.

Vitamin D plays a crucial role in preventing protein insolubility and appears to activate endogenous defense systems, potentially slowing aging and reducing the risk of various diseases, including neurological disorders.

USING C. ELEGANS AS A MODEL ORGANISM FOR AGING RESEARCH

Dr. Gordon Lithgow utilizes the transparent, millimeter-sized nematode worm, C. elegans, as a powerful model system for aging research. Its short lifespan (15-20 days) and the ability to observe tissues in real-time make it ideal for economically screening numerous compounds for longevity-promoting effects. This contrasts with mice, which have much longer lifespans, making aging studies significantly more expensive and time-consuming. The worms exhibit observable aging processes, including behavioral changes and functional decline, making interventions that slow or reverse these changes readily apparent.

THE ROLE OF PROTEIN HOMEOSTASIS AND AGGREGATION IN AGING

A central focus of Dr. Lithgow's work is proteostasis, or protein homeostasis, and its decline with age. Proteins lose their correct three-dimensional shape, leading to misfolding and aggregation, which can be toxic. This phenomenon is well-known in neurodegenerative diseases like Alzheimer's and Parkinson's, but Dr. Lithgow's research, corroborated by other labs, reveals that hundreds, if not thousands, of proteins undergo conformational changes and become insoluble during normal aging. These proteins are enriched for those that influence lifespan, directly linking protein aggregation to the aging process itself.

HORMETIC STRESSORS AND THEIR LONGEVITY BENEFITS

Hormetic stressors, such as heat shock and fasting, can paradoxically extend lifespan by activating cellular defense mechanisms. A single heat shock exposure in worms can increase lifespan by activating heat shock proteins (HSPs), which are molecular chaperones that help proteins refold correctly. Multiple heat shocks yield even greater effects. These stress responses also ramp up autophagy, the process of clearing out damaged proteins and cellular components. This concept is highly relevant to humans, as evidenced by studies showing pre-stressing organs before surgery can improve recovery and by the widespread use of saunas for health benefits.

THE POTENTIAL OF VITAMIN D IN LONGEVITY AND DISEASE PREVENTION

Research has revealed that Vitamin D plays a significant role in protein homeostasis and aging. Studies in C. elegans engineered to express human beta-amyloid showed that Vitamin D suppressed paralysis by preventing protein insolubility across hundreds of proteins. This effect appears to be mediated by activating endogenous defense systems, including the NRF2 pathway, which regulates oxidative stress responses. Epidemiological data in humans also links Vitamin D deficiency to an increased risk of various chronic diseases, including cancers and neurological disorders, suggesting Vitamin D deficiency might act as an accelerator of aging.

IRON METABOLISM AND ITS IMPACT ON AGING AND NEURODEGENERATION

The role of iron in aging and disease is another key area of investigation. Dr. Lithgow's lab found that elevated dietary iron in worms accelerated aging and the accumulation of insoluble proteins. Conversely, feeding worms an iron chelator extended their lifespan and protected against protein aggregation. This aligns with observations in human neurological diseases like Parkinson's and Alzheimer's, where iron dysregulation is implicated. Genetic predispositions, such as in hemochromatosis, can lead to excessive iron absorption, potentially influencing aging trajectories and disease risk.

TRANSLATING WORM AGING RESEARCH TO HUMAN HEALTH

Dr. Lithgow's research, while conducted in model organisms like C. elegans, has significant implications for human health. The discovery of compounds that extend lifespan and improve healthspan in worms, coupled with findings on heat shock, Vitamin D, and iron metabolism, highlights conserved aging mechanisms. Furthermore, Dr. Lithgow is involved in a collaborative effort to test compounds for longevity effects across different worm genetic backgrounds, aiming to identify robust candidates for further study. This work underscores the potential for translating basic aging research into practical interventions for human health and disease prevention.

Mentioned in This Episode

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Common Questions

C. elegans worms are transparent, allowing researchers to see tissues aging in real-time. They also have a short lifespan of 15-20 days, which enables rapid and economical experiments to test compounds for longevity effects.

Topics

Proteostasis C. Elegans Iron Metabolism Compound Screening

Mentioned in this video

personTom Johnson

Along with Mike Class, adopted C. elegans in the late 1980s to study longevity.

conceptproteasome

A cellular machine responsible for degrading damaged proteins, whose activity can be increased by heat stress.

studyAlzheimer's disease risk and sauna use

A study showing that men using the sauna 4-7 times a week had a 60% reduction in Alzheimer's disease risk.

softwaretransferrin

A gene involved in binding free iron. Certain polymorphisms in transferrin and hemochromatosis genes increase Alzheimer's risk.

studyVitamin D receptor knockout mice

Mice lacking the Vitamin D receptor exhibit a progeria-like phenotype with accelerated aging signs, suggesting a role for Vitamin D in regulating the aging process.

personMonica Driscoll

Co-investigator in the consortium for testing longevity compounds in worms.

conceptinflammatory cytokines

Signaling molecules that can contribute to inflammation and damage DNA and proteins, implicated in aging.

organizationBuck Institute for Aging

An institute where Dr. Gordon Lithgow works, focused on aging research.

personSydney Brenner

Suggested C. elegans as a genetic system for studying neurobiology and neuronal development in the 1960s.

personJulie Anderson

Dr. Lithgow's wife, whose work on Parkinson's disease and iron's role in mitochondrial damage inspired his research.

personPatrick Phillips

Co-investigator in the consortium for testing longevity compounds in worms.

supplementthiovitidin tea

A compound that binds amyloid and promotes protein homeostasis, found to be robust and reproducible in extending lifespan in C. elegans and other species.

softwareFoundMyFitness.com/crowdsponsor

A page on the Found My Fitness website where listeners can support the podcast.

softwareHSF-1

A transcription factor involved in the heat shock response, discussed in relation to human heat shock protein activation.

personChris Link

Developed a C. elegans strain engineered to express human A beta, used to screen for compounds that suppress paralysis related to protein aggregation.

supplementreactive oxygen species

conceptMyrosinase

toolNRF2