The interaction between disrupted lipid homeostasis and immune response is implicated in the pathogenesis of several diseases, but the molecular bridges between the major players are still a matter of controversy. Our systemic study of the inflammatory cytokine tumor necrosis factor-alpha (TNF-α) in the livers of mice exposed to 20-h cytokine/fasting for the first time shows that TNF-α interferes with adaptation to fasting and activates harmful proatherogenic pathways, partially through interaction with the insulin-Insig-sterol regulatory element binding protein (Srebp) signaling pathway. In addition to the increased expression of acute-phase inflammatory genes, the most prominent alterations represent modified lipid homeostasis observed on the gene expression and metabolite levels. These include reduction of HDL-cholesterol, increase of LDL-cholesterol, and elevated expression of cholesterogenic genes, accompanied by increase of potentially harmful precholesterol metabolites and suppression of cholesterol elimination through bile acids, likely by farnesoid X receptor-independent mechanisms. On the transcriptional level, a shift from fatty oxidation toward fatty acid synthesis is observed. The concept of the influence of TNF-α on the Srebp regulatory network, followed by downstream effects on sterol metabolism, is novel. Observed acute alterations in lipid metabolism are in agreement with chronic disturbances found in patients.
|Original language||English (US)|
|Number of pages||12|
|State||Published - Oct 22 2007|
- Acute response
ASJC Scopus subject areas