Complement C3a, CpG oligos, and DNA/C3a complex stimulate IFN-α production in a receptor for advanced glycation end product-dependent manner.
The receptor for advanced glycation end products (RAGE) is a multiligand transmembrane receptor implicated in a number of diseases including autoimmune diseases. To further understand the pathogenic mechanism of RAGE in these diseases, we searched for additional ligands. We discovered that C3a bound to RAGE with an EC(50) of 1.9 nM in an ELISA, and the binding was increased both in magnitude (by >2-fold) and in affinity (EC(50) 70 pM) in the presence of human stimulatory unmethylated cytosine-guanine-rich DNA A (hCpGAs). Surface plasmon resonance and fluorescence anisotropy analyses demonstrated that hCpGAs could bind directly to RAGE and C3a and form a ternary complex. In human PBMCs, C3a increased IFN-α production in response to low levels of hCpGAs, and this synergy was blocked by soluble RAGE or by an Ab directed against RAGE. IFN-α production was reduced in response to mouse CpGAs and C3a in RAGE(-/-) mouse bone marrow cells compared wild-type mice. Taken together, these data demonstrate that RAGE is a receptor for C3a and CpGA. Through direct interaction, C3a and CpGA synergize to increase IFN-α production in a RAGE-dependent manner and stimulate an innate immune response. These findings indicate a potential role of RAGE in autoimmune diseases that show accumulation of immunostimulatory DNA and C3a.
Ruan
Benfang Helen
BH
Inflammation and Immunology, Pfizer Biotherapeutics Research and Development, Cambridge, MA 02140, USA.
Li
Xin
X
Winkler
Aaron R
AR
Cunningham
Kristina M
KM
Kuai
Jun
J
Greco
Rita M
RM
Nocka
Karl H
KH
Fitz
Lori J
LJ
Wright
Jill F
JF
Pittman
Debra D
DD
Tan
Xiang-Yang
XY
Paulsen
Janet E
JE
Lin
Lih Ling
LL
Winkler
David G
DG
D000818:Animals; D015926:Complement C3a / Q000276:immunology / Q000378:metabolism*; D004247:DNA / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009841:Oligonucleotides / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D000067759:Receptor for Advanced Glycation End Products / Q000276:immunology / Q000378:metabolism*; D020349:Surface Plasmon Resonance
D009841:Oligonucleotides; D000067759:Receptor for Advanced Glycation End Products; D015926:Complement C3a; D007371:Interferon-gamma; D004247:DNA