Neutrophils preserve energy storage in sympathetically activated adipocytes.

Abstract

Adipose tissue maintains energy homeostasis by storing lipids during nutrient surplus and releasing them through lipolysis in times of energy demand^1,2. While lipolysis is essential for short-term metabolic adaptation, prolonged metabolic stress requires adaptive changes that preserve energy reserves^2,3. Here we report that β₃-adrenergic activation of adipocytes induces a transient and depot-specific infiltration of neutrophils into white adipose tissue (WAT), particularly in lipid-rich visceral WAT. Neutrophil recruitment requires the stimulation of both lipolysis and p38 MAPK in adipocytes, and is mediated by the secretion of leukotriene B4. Recruited neutrophils undergo activation in situ, and locally secrete IL-1β, which suppresses lipolysis and limits excessive energy loss. Neutrophil depletion or blockade of IL-1β production increases lipolysis, leading to reduced WAT mass after repeated β₃-adrenergic stimulation. Together, these findings reveal a role of neutrophil-derived IL-1β in preserving lipid stores during metabolic stress, highlighting a physiological function of innate immune cells in limiting lipid loss and maintaining energy homeostasis.