Role of mannose receptor in oligochitosan-mediated stimulation of macrophage function

In this paper, we aimed to study the role of mannose receptor (MR) in oligochitosan induced RAW264.7 (a murine macrophage cell line) activation. Oligochitosan, which has 3-10 saccharide (N-acetyl-glucosamine or glucosamine) residues, was prepared by enzymatic hydrolysis of chitosan using cellulase. Fluorophore 2-aminoacridone was conjugated to oligochitosan to observe cellular events of oligochitosan-RAW264.7 interaction under Confocal Laser Microscopy. RT-PCR was performed to assess the level of tumor necrosis factor-alpha (TNF-alpha) secretion. Free cytosolic Ca(2+) was measured using the fluorescent Ca(2+) indicator Fluo3/AM. We found that MR was the major receptor responsible for oligochitosan uptake. MR was also engaged in oligochitosan induced TNF-alpha enhancement and [Ca(2+)](in) flux and may serve as a signaling receptor in oligochitosan-induced activation of macrophage function.