Liver from CSF1-Fc- or PBS-treated neonatal rats and rat bone marrow derived macrophages

Signalling via the colony stimulating factor 1 receptor (CSF1R) controls the survival, differentiation and proliferation of macrophages which are a source of the somatic growth factor insulin growth factor 1 (IGF1). Treatment of newborn mice with CSF1 has previously been shown to produce an increase in somatic growth rate and we hypothesised that treatment of neonatal low birth weight (LBW) rats with CSF1 would do the same. Growth rates were not affected, yet CSF1 treatment caused an unexpectedly large, but reversible increase in liver size and hepatic fat deposition in both normal and LBW rats. By transcriptional profiling, we have highlighted numerous CSF1-regulated genes known to be involved in lipid droplet formation in the liver and novel candidate genes for further investigation. In contrast to mice and weaner pigs, CSF1 treatment did not increase hepatocyte proliferation in neonatal rats, rather the data were consistent with increased macrophage proliferation instead. This suggests that Kupffer cells promote lipid accumulation in neonates and treatment to ablate CSF1R signalling may reverse lipid accumulation in the liver.

9

Pridans C, Sauter KA, Irvine KM, Davis GM, Lefevre L, Raper A, Rojo R, Nirmal AJ, Beard P, Cheeseman M, Hume DA