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Imperative Role of Macrophage in Maintaining Systemic Energy Homeostasis
Author(s) -
Lee Bonggi,
Qiao Liping,
Kinney Brice,
Shao Jianhua
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.570.5
Subject(s) - energy homeostasis , endocrinology , macrophage , medicine , inflammation , homeostasis , systemic inflammation , adipose tissue , immune system , insulin resistance , biology , white adipose tissue , immunology , insulin , obesity , in vitro , biochemistry
Macrophages are residential immune cells and present in almost all tissues. Increased macrophage infiltration in white adipose tissues (WAT) has been recognized as a pro‐inflammatory factor causing insulin resistance in obesity. However, the functions of macrophage in systemic energy metabolism, particularly under non‐obese conditions, are largely unknown. By conditional expressing of diphtheria toxin (DT) receptor and DT administration, we depleted macrophages in mice and studied the effects on energy metabolism. DT injection efficiently depleted macrophages. We observed robustly reduced body weight with a significant decrease in body fat and food intake in DT‐injected mice. Those phenotypes were recovered when we stop injecting DT. Interestingly, macrophage depletion even reduced energy expenditure during dark cycle, suggesting that decrease of body fat is mainly due to reduced food intake. As a potential factor related to altered energy balance, strikingly high levels of inflammatory cytokines were detected in circulation as well as their expression in multiple tissues including hypothalamus, WAT, and liver of macrophage‐depleted mice. Paradoxically, insulin sensitivity was not altered despite increased systemic inflammation. Together, our results indicate that macrophage play an essential role in regulating energy homeostasis under non‐obese conditions.