Abstract
Macrophages have been recognized as key players in non-alcoholic fatty liver disease (NAFLD). Our aim was to assess whether pharmacological attenuation of macrophages can be achieved by imatinib, an anti-leukemia drug with known anti-inflammatory and anti-diabetic properties, and how this impacts on NAFLD. We analyzed the pro- and anti-inflammatory gene expression of murine macrophages and human monocytes in vitro in the presence or absence of imatinib. In a time-resolved study, we characterized metabolic disease manifestations such as hepatic steatosis, systemic and adipose tissue inflammation as well as lipid and glucose metabolism in obese mice at one and three months of imatinib treatment. Our results showed that imatinib lowered pro-inflammatory markers in murine macrophages and human monocytes in vitro. In obese mice, imatinib reduced TNFα-gene expression in peritoneal and liver macrophages and systemic lipid levels at one month. This was followed by decreased hepatic steatosis, systemic and adipose tissue inflammation and increased insulin sensitivity after three months. As the transcription factor sterol regulatory element-binding protein (SREBP) links lipid metabolism to the innate immune response, we assessed the gene expression of SREBPs and their target genes, which was indeed downregulated in the liver and partially in peritoneal macrophages. In conclusion, targeting both inflammatory and lipogenic pathways in macrophages and liver as shown by imatinib could represent an attractive novel therapeutic strategy for patients with NAFLD.