Constitutive and regulated expression and secretion of interferon-γ- inducible protein 10 (IP-10/CXCL10) in human adipocytes

C. Herder, H. Hauner, K. Kempf, H. Kolb, T. Skurk

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Objective: Chemokine secretion by adipocytes has been postulated to initiate leukocyte infiltration in adipose tissue and might mediate an important step in the establishment of obesity-related chronic immune activation. The chemokine interferon (IFN)γ-inducible protein-10 (IP-10/CXCL10) is a chemoattractant for various leukocyte subsets and has been implicated in the pathogenesis of atherosclerosis. This study investigates whether IP-10 is expressed in human adipocytes and whether its release is regulated by body mass index (BMI) or immunological stimuli. Methods: In cultures of human mature adipocytes and in vitro differentiated adipocytes, IP-10 expression under basal conditions and in the presence of IFNγ, lipopolysaccharide (LPS) or interleukin (IL)-4 was characterized by reverse transcriptase-polymerase chain reaction, Luminex technology and immunofluorescence. Results: IP-10 was expressed and secreted constitutively in most cultures of mature adipocytes from omental and subcutaneous (s.c.) depots. The association between IP-10 release and donor BMI was not significant. In in vitro differentiated adipocytes from s.c. and mammary depots and in mature s.c. adipocytes, IP-10 secretion was strongly upregulated by IFNγ, whereas LPS or IL-4 did not affect IP-10 expression in s.c. mature adipocytes. Immunofluorescence confirmed IP-10 expression in adipocytes with abundant lipid droplets. Conclusion: Mature human adipocytes express and secrete the chemokine IP-10 and are thus identified as a novel cellular source of this disease-related immune mediator. IP-10 expression could be significantly induced by IFNγ, but not by LPS, which points to both similar reactivities and functional differences between adipocytes and innate immune cells.

Original languageEnglish
Pages (from-to)403-410
Number of pages8
JournalInternational Journal of Obesity
Volume31
Issue number3
DOIs
StatePublished - Mar 2007

Keywords

  • Adipocytes
  • CXCL10
  • Chronic inflammation
  • Human adipose tissue
  • IP-10

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