Social reprogramming in ants induces longevity-associated glia remodeling

Area of Science:

• Neuroscience
• Insect Biology
• Genetics

Background:

• Social insects exhibit distinct castes (workers, queens) from identical genomes, differing in behavior and lifespan.
• In *Harpegnathos saltator* ants, workers can transition to a queen-like gamergate state, altering social behavior and extending lifespan.

Purpose of the Study:

• To investigate the neuronal and glial population changes associated with the worker-to-gamergate transition in *Harpegnathos saltator*.
• To understand the role of glia in brain aging and injury response in relation to social status and lifespan.

Main Methods:

• Single-cell RNA sequencing to compare neuronal and glial populations before and after the social transition.
• Brain injury assays to assess the damage response gene *Mmp1* activation in workers and gamergates of different ages.
• Comparative analysis of ensheathing glia in *Drosophila* to identify conserved age-related changes.

Main Results:

• The worker-to-gamergate transition led to an expansion of neuroprotective ensheathing glia.
• Older workers showed weaker *Mmp1* gene activation upon brain injury and a decline in ensheathing glia.
• Long-lived gamergates maintained a higher proportion of ensheathing glia and a robust *Mmp1* response to injury into old age.
• Evidence of age-associated decline in ensheathing glia was also observed in *Drosophila*.

Conclusions:

• Ensheathing glia play a crucial role in maintaining brain health and injury response, particularly in long-lived individuals.
• The expansion and maintenance of ensheathing glia are key factors in the lifespan extension and enhanced resilience observed in gamergates.
• These findings suggest conserved mechanisms of glial function and aging across different insect species.