Adipocyte-macrophage interaction may mediate LPS-induced low-grade inflammation: Potential link with metabolic complications

Hideo Nakarai, Akiko Yamashita, Shintaro Nagayasu, Misaki Iwashita, Sonoko Kumamoto, Hideki Ohyama, Masaki Hata, Yoshihiko Soga, Akifumi Kushiyama, Tomoichiro Asano, Yoshimitsu Abiko, Fusanori Nishimura

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38 Citations (Scopus)

Abstract

Chronic low-grade infection has been suggested to be associated with metabolic disorder such as diabetes. However, the molecular mechanism underlying this important association is largely unknown. The only clue established so far is that many subjects exhibit elevated levels of C-reactive protein as measured by highly sensitive assay. Here, we hypothesized that adipocyte-macrophage interaction plays a key role in amplifying such low grade infection to the level of influencing metabolic disorders. The presence of macrophages in abdominal adipose tissues was investigated by immunohistochemistry. To see whether molecules associated with acute phase protein, LPS signaling, and persistent recruitment of monocytes, are produced at higher amounts in adipocytes co-cultured with macrophages stimulated with low concentration of LPS (1 ng/ml), we measured serum amyloid A (SAA), LPS binding protein (LBP), soluble CD14 (sCD14), and RANTES levels in culture supernatant of co-cultures. Lastly, we investigated in vivo effect of low-grade LPS infusion on the production of these molecules using obese model mice. The macrophages were certainly identified in abdominal adipose tissues. Investigated molecules, especially LBP, SAA, and RANTES were produced at higher amounts in co-cultures stimulated with LPS compared with the cells without LPS. The ob/ob, and high-fat diet-induced obesity mice produced higher amounts of LBP, SAA, and RANTES one day after LPS infusion (1 ng/ml/g body weight) compared with ob/- and normal-fat fed control mice. Thus, adipocytes and infiltrated macrophages, and their interaction with low endotoxin stimulation appear to play an important role in amplifying and maintaining LPS-induced low-grade inflammation.

Original languageEnglish
Pages (from-to)164-170
Number of pages7
JournalInnate Immunity
Volume18
Issue number1
DOIs
Publication statusPublished - Feb 1 2012

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Keywords

  • Endotoxemia
  • LPS binding protein
  • adipocyte-macrophage interaction
  • low-grade inflammation
  • metabolic diseases

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Molecular Biology
  • Cell Biology
  • Infectious Diseases

Cite this

Nakarai, H., Yamashita, A., Nagayasu, S., Iwashita, M., Kumamoto, S., Ohyama, H., Hata, M., Soga, Y., Kushiyama, A., Asano, T., Abiko, Y., & Nishimura, F. (2012). Adipocyte-macrophage interaction may mediate LPS-induced low-grade inflammation: Potential link with metabolic complications. Innate Immunity, 18(1), 164-170. https://doi.org/10.1177/1753425910393370