Siglec-9 enhances IL-10 production in macrophages via tyrosine-based motifs

Enhanced lentiviral vector production in 293FT cells expressing Siglec-9

“…We previously reported that Siglec-9 strongly stimulated the production of IL-10 by RAW264 cells, a mouse macrophage-like cell line, when these cells were stimulated with various TLR ligands (Ando et al 2008). Since this enhancement was also associated with higher expression of IL-10 mRNA, we applied the typical luciferase assay to examine the underlying mechanisms.…”

“…The construction of human Siglec-9-expressing plasmids and the establishment of RAW264 cell lines stably expressing Siglec-9 were described previously (Ando et al 2008). 293FT cells were purchased from Invitrogen and maintained in DMEM (Sigma-Aldrich Japan, Tokyo, Japan) supplemented with 10 % FCS, 1 mM sodium pyruvate (Wako Pure Chemical Industries), 1 % non-essential amino acids (Gibco Life Technologies, Grand Island, NY, USA), 0.03 % L-glutamine, 100 U/ml penicillin G, and 100 lg/ml streptomycin.…”

“…Members of CD33-related Siglecs have been shown to downregulate both innate and acquired immune responses, and this may occur via cytosolic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) residing in the cytoplasmic region of the protein (Avril et al 2005;Ikehara et al 2004;Lajaunias et al 2005;Nicoll et al 2003;Paul et al 2000;Ulyanova et al 1999;von Gunten et al 2005;Zhang et al 2007). We previously suggested that CD33-related Siglecs may antagonize Toll-like receptor (TLR)-mediated inflammatory responses, leading to a reduction in proinflammatory cytokines and increase in the production of an antiinflammatory cytokine (Ando et al 2008). Furthermore, a previous study reported that Siglec-5 and sialoadhesin (Siglec-1) mediated the uptake of Neisseria meningitides, one of the sialic acid-harboring pathogens, into macrophages (Jones et al 2003).…”

Effects of Siglec on the expression of IL-10 in the macrophage cell line RAW264

“…The macrophage cell line RAW264 and its derivative expressing Siglec-9 was described previously (Ando et al 2008). These cells were maintained in RPMI1640 (Nissui, Tokyo, Japan) containing 10 % heat-inactivated fetal calf serum (PAA Laboratories, Pasching, Austria), 0.03 % L-glutamine (Wako, Osaka, Japan), 5 9 10 -5 M 2-mercaptoethanol (Wako), 100 U/ml penicillin G (Wako), and 100 lg/ml streptomycin (Wako).…”

“…We previously reported that Siglec-9, a member of CD33-related Siglecs, inhibited the production of proinflammatory cytokines and enhanced that of anti-inflammatory cytokine interleukin-10 (IL-10), induced by various ligands for TLRs. The ITIMs of Siglec-9 were previously shown to play an indispensable role in modulating the expression of cytokines (Ando et al 2008). …”