Dysregulation of adipose ILC2 underlies thermogenic failure in aging

Aging impairs the integrated immunometabolic responses which have evolved to maintain core body temperature in homeotherms to survive cold-stress, infections, and dietary restriction. Adipose tissue inflammation regulates the thermogenic stress response but how adipose tissue-resident cells instigate thermogenic failure in aged are unknown. Here, we define alterations in the adipose-resident immune system and identify that type 2 innate lymphoid cells (ILC2) are lost in aging. Restoration of ILC2 numbers in aged mice to levels seen in adults through IL-33 supplementation failed to rescue old mice from metabolic impairment and cold-induced lethality. Transcriptomic analyses revealed intrinsic defects in aged ILC2, and adoptive transfer of adult ILC2 are sufficient to protect old mice against cold. Thus, the functional defects in adipose ILC2 during aging drive thermogenic failure. One Sentence Summary Age-related changes in adipose tissue drive reprogramming of ILC2 that leads to impaired cold tolerance ### Competing Interest Statement The authors have declared no competing interest.