Pattern recognition receptors in liver sinusoidal endothelial cells : Roles in the innate immune system and scavenger functions

Abstract

Effective removal of unwanted self and non-self molecules from blood is essential to keep the organism healthy. Liver sinusoidal endothelial cells (LSECs) have been shown to effectively clear such macromolecules via receptor-mediated endocytosis. The cells express several high affinity endocytosis receptors, including the mannose receptor (MR), and several scavenger receptors (SRs), which are known also for their role as pattern recognition receptors (PRRs) in host defence. The present study shows that LSEC endocytosis 1) is involved in regulation of liver immune responses by delivering ligands to Toll-like receptor 9 (an intracellular PRR) 2) is necessary to maintain the very effective lysosomal degradation of endocytosed material that characterizes the physiological function of LSECs 3) appears to be negatively affected at old age.