Gene silencing in adipose tissue macrophages regulates whole-body metabolism in obese mice

Proc Natl Acad Sci U S A. 2013 May 14;110(20):8278-83. doi: 10.1073/pnas.1300492110. Epub 2013 Apr 29.


Adipose tissue (AT) inflammation and infiltration by macrophages is associated with insulin resistance and type 2 diabetes in obese humans, offering a potential target for therapeutics. However, whether AT macrophages (ATMs) directly contribute to systemic glucose intolerance has not been determined. The reason is the lack of methods to ablate inflammatory genes expressed in macrophages specifically localized within AT depots, leaving macrophages in other tissues unaffected. Here we report that i.p. administration of siRNA encapsulated by glucan shells in obese mice selectively silences genes in epididymal ATMs, whereas macrophages within lung, spleen, kidney, heart, skeletal muscle, subcutaneous (SubQ) adipose, and liver are not targeted. Such administration of GeRPs to silence the inflammatory cytokines TNF-α or osteopontin in epididymal ATMs of obese mice caused significant improvement in glucose tolerance. These data are consistent with the hypothesis that cytokines produced by ATMs can exacerbate whole-body glucose intolerance.

Keywords: RNAi; immune cells; obesity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / cytology*
  • Animals
  • Cytokines / metabolism
  • Epididymis / cytology
  • Epididymis / metabolism
  • Gene Silencing*
  • Glucose Intolerance / genetics
  • Glucose Intolerance / metabolism*
  • Inflammation
  • Macrophages / cytology
  • Macrophages / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Obese
  • Microscopy, Fluorescence
  • Obesity / physiopathology*
  • Osteopontin / metabolism
  • Phagocytosis
  • RNA Interference
  • RNA, Small Interfering
  • Tumor Necrosis Factor-alpha / metabolism


  • Cytokines
  • RNA, Small Interfering
  • Tumor Necrosis Factor-alpha
  • Osteopontin