Abstract
Macrophage infiltration into adipose tissue increases with obesity, a condition associated with low-grade inflammation and insulin resistance. We investigated the direct effects of macrophage-secreted factors on adipocyte inflammation and insulin resistance. 3T3-L1 adipocytes incubated with media conditioned by RAW264.7 macrophages (RAW-CM) showed dramatically increased transcription of several inflammation-related genes, greater nuclear factor kappa B (NF-κB) activity, and enhanced binding of U937 monocytes. All of these effects were prevented by co-incubation with pyrrolidinedithiocarbamate, an NF-κB inhibitor. Adipocytes incubated with RAW-CM also released more non-esterified fatty acids and this increased lipolysis was not suppressed by insulin. In addition, RAW-CM treatment decreased insulin-stimulated glucose uptake in adipocytes. Taken together, these results indicate that macrophage-secreted factors induce inflammatory responses and reduce insulin responsiveness in adipocytes. These effects of macrophage-secreted factors on adipocytes may contribute significantly to the systemic inflammation and insulin resistance associated with obesity.
Original language | English (US) |
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Pages (from-to) | 507-514 |
Number of pages | 8 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 341 |
Issue number | 2 |
DOIs | |
State | Published - Mar 10 2006 |
Externally published | Yes |
Keywords
- Adipocyte
- Inflammation
- Insulin resistance
- Macrophage
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology