Rapamycin Mitigates A Sex-Biased Convergent Aging Trajectory
Research Summary
A single-nucleus atlas of the whole fruit fly asking which cells respond to rapamycin during aging. The authors report that aging cells from many tissues drift toward a shared, rapamycin-sensitive state marked by Fkbp12 – the protein rapamycin needs to inhibit mTORC1 – and mTORC1-linked metabolism, and that this state is reduced more strongly in females, the sex with the larger lifespan extension.
Who Or What Was Studied?
Adult fruit flies (Drosophila melanogaster) of both sexes, kept on food with or without 20 µM rapamycin starting at day 10 of life. The Rapamycin Fly Cell Atlas (Rapa-FCA) contains 505,731 high-quality single nuclei from heads and bodies sampled at days 7, 30, 50 and 70, annotated into 18 broad cell classes and 181 cell types. Lifespan was measured in parallel in several hundred flies per sex and group.
What Did The Research Show?
- Rapamycin extended median lifespan in both sexes: females from 68.9 to 77.7 days (about 12%) and males from 67.5 to 71.9 days (about 7%).
- Responses were highly cell-type specific: reproductive, digestive and neuromuscular tissues showed the strongest transcriptional changes, while most neuronal and glial populations changed only modestly.
- Aging nuclei from different tissues – female germline, male accessory gland and ventral nerve cord – converged on a shared transcriptomic state defined by 469 genes, the Convergent Aging Trajectory (CAT), enriched for glycolysis, lipid synthesis and Fkbp12.
- CAT-high nuclei accumulated with age and were reduced by rapamycin, more in females than males; in the female germline the aged lineage was about 35% smaller at day 50, and rapamycin-treated females produced more offspring (p = 0.0019).
- Rapamycin preserved female neuromuscular aging markers: more neuromuscular junction boutons, preserved muscle nuclei and better climbing in aged females, with transcriptomic aging clocks predicting younger cell ages in female tissues; many male cell types showed benefits only later in life.
Limitations And Interpretation
- Fruit fly data at a single dose (20 µM): the study does not show that rapamycin slows human aging and supports no dosing recommendation.
- This is a bioRxiv preprint posted in July 2026 and, in this version, has not been peer reviewed.
- Whether CAT-high nuclei drive aging or are a by-product of it is not established, and rapamycin levels in individual tissues such as the brain were not measured directly.
- Some male cell types showed neutral or potentially unfavorable shifts at day 30, so the atlas also maps where rapamycin did not help.
Summary prepared from the published paper (abstract and full text where accessible). This is not medical advice — always consult the original publication.