Cold Extends Worm Lifespan via Muscle-Produced BH2 Metabolite, Study Finds

Key points

• A study in Nature reveals that mild cold (15°C) extends the lifespan of C. elegans worms by activating an active biological pathway, not just slowing metabolism.
• Cold temperatures increase the production of the enzyme CAT-4 in worm muscle tissue, which stimulates the synthesis and release of the metabolite dihydrobiopterin (BH2).
• BH2 travels to other tissues where it is converted into BH4, enabling the enzyme PAH-1 to produce the amino acid tyrosine, which supports protein homeostasis.
• Disrupting this pathway reduces the lifespan benefits of cold, while genetically boosting CAT-4 or supplementing with BH2/tyrosine extends lifespan even at 20°C or 25°C.
• In human cell models, BH2 and tyrosine supplementation reduced the accumulation of harmful proteins associated with Huntington’s disease and amyotrophic lateral sclerosis (ALS).
• The findings suggest that targeting muscle tissue could provide organism-wide protection against age-related protein damage, opening avenues for therapeutic approaches that do not require lowering body temperature.

Background

Scientists have known for over a century that moderate cold extends the lifespan of various animals, including worms, flies, and rodents. Previous hypotheses suggested this was a passive thermodynamic effect, but recent research indicates it is an actively regulated biological process. Earlier studies by the same team found that cold activates proteasomes to remove harmful protein clumps in C. elegans. This new study identifies the systemic metabolic signals, specifically the BH2 pathway, that coordinate these protective responses across tissues.

How outlets are covering it

All four sources agree on the core findings: cold triggers BH2 production in muscle, which extends lifespan and improves proteostasis in C. elegans, and that this can be mimicked without cold. ScienceAlert and ZME Science emphasize the potential for future therapies that mimic cold benefits without temperature changes, highlighting the surprise of the researchers. BioTechniques provides more technical detail, noting that an untargeted metabolomics analysis identified 64 metabolites increased at 15°C, with BH2 being the most strongly induced, and that tissue-specific knockdown experiments confirmed muscle as the key source. UA.NEWS provides a concise summary of the pathway and its implications for neurodegenerative diseases. ZME Science adds context on the limitations, noting that humans are warm-blooded and that the worm results do not automatically translate to humans, and that tyrosine supplements are not recommended based on this study. No significant disagreements were found among the sources.

Why it matters

This study provides a concrete mechanism for the long-observed link between cold and longevity, moving beyond passive thermodynamic explanations. It identifies a specific metabolic pathway (BH2) that can be targeted to extend lifespan and protect against age-related protein damage, even without cold exposure. This could lead to new therapeutic approaches for aging and neurodegenerative diseases like Huntington’s and ALS, potentially by targeting muscle tissue or supplementing with BH2 or tyrosine, although significant research is needed before human applications.

What to watch

Further research is needed to determine if these findings can be safely translated to humans. The team will likely investigate the translational potential of BH2 and tyrosine supplementation in more complex models, considering additional cell processes and signals that may interfere with the pathway in humans. They may also explore the specific mechanisms by which BH2 and tyrosine reduce protein aggregation and programmed cell death in human motor neurons with ALS-associated mutations.