A protein found deep in the brain's hypothalamus may be a key driver of aging, and restoring it in old mice reversed several signs of physical and cognitive decline within 30 days, according to research that is drawing fresh attention this week after a new summary from the journal publisher PLOS. The underlying study is not brand new — it was first published in 2023 — but it is circulating widely again as researchers continue to probe the brain's role in whole-body aging.
The research, led by Lige Leng's team at Xiamen University and published in PLOS Biology, found that levels of the protein Menin decline with age specifically in neurons of the ventromedial hypothalamus, a brain region that helps regulate metabolism. When the researchers used gene-delivery techniques to lower Menin in young mice, the animals developed hypothalamic inflammation along with aging-like traits: thinner skin, reduced bone density, worse memory and learning performance, and shorter lifespans. Restoring Menin in 20-month-old mice — elderly by lab standards — reversed several of those changes within a month and extended survival in follow-up tracking.
The team traced part of the effect to a knock-on chemical shortage. Menin helps drive production of an enzyme that the brain uses to make D-serine, an amino acid involved in learning and memory. As Menin fell, D-serine dropped too. When the researchers gave aged mice D-serine in their drinking water for three weeks, the animals' memory and learning test scores improved — but their bones and skin did not get thicker, suggesting D-serine addresses only part of what Menin does.
An old finding, a new audience
The hypothalamus has drawn growing interest from aging researchers because it sits at the intersection of metabolism, inflammation and the nervous system — all processes known to shift with age. Other labs have reported related hypothalamic inflammation effects on lifespan in mice, though, as outside reviewers have noted, those studies don't fully confirm the Menin pathway on their own. The renewed coverage this month does not add new data to the original paper; it is, by the publisher's own framing, a recap aimed at a wider audience rather than a new result.
Human evidence remains thin. A small 2016 clinical trial gave D-serine to 50 healthy older adults and found improvement on only one of several cognitive measures tested. Researchers have also flagged that high doses of D-serine raised kidney safety concerns in animal experiments, underscoring that the compound is not an established treatment for brain aging.
No human trials of Menin-restoring gene therapy have been reported, and the Xiamen team itself has cautioned that much remains unknown about what causes Menin to decline in the first place. For now, the findings stand as a mouse-only proof of concept: a reminder that a single hypothalamic protein can ripple outward into bone, skin and memory, but not yet a pathway to a human anti-aging therapy.
