CD68 on rat macrophages binds tightly to S100A8 and S100A9 and helps to regulate the cells' immune functions.
S100A8 and S100A9 (S100 proteins) are regulators of immune cells of myeloid origin. Whereas S100 proteins are found at high concentrations in such cells, their immunologic roles remain unclear. We focused on cluster of differentiation 68 (CD68). The aim of this study is to investigate whether CD68 binds to extracellular S100A8 and/or S100A9 and subsequently participates in the regulation of the cells' immune functions. ELISA and affinity chromatography showed that both recombinant rat S100A8 (r-S100A8) and r-S100A9 bound to r-CD68, but not to r-CD14. Flow cytometry clearly showed evidences supporting above the 2 results. As analyzed by flow cytometry, a less amount of r-S100A8 or r-S100A9 bound to the macrophages treated with some deglycosylation enzymes. In an in vitro assay, the expression levels of S100A8 and S100A9 were significantly suppressed after the macrophages had been treated with an anti-CD68 antibody (ED1). As stimulated macrophages with r-S100A9, the expression of IL-1β mRNA in macrophages, which were treated with anti-TLR4 or -RAGE antibodies, was significantly suppressed. r-S100A8 up-regulated IL-6 and IL-10 mRNAs, while r-S100A9 did TNF-α and IL-6 mRNAs, although these regulations were not statistically significant. Small interfering CD68 also significantly suppressed activation of macrophages through an autocrine pathway by r-S100A8 or r-S100A9. In macrophages stimulated with LPS, fluorescent immunologic staining showed that most CD68 colocalized with S100A8 or S100A9 and that the levels of all 3 molecules were markedly increased. In conclusion, CD68 on macrophages binds to S100A8 and S100A9 and thereby, plays a role in the regulation of the cells' immune functions.
Department of Clinical Laboratory Science, Faculty of Health Care, Tenri Health Care University, Nara, Japan.|Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Kohki
K
Okada
Research and Development Section, Diagnostic Department, Yamasa Corporation, Chiba, Japan.
Satoshi
S
Arai
Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Hiroshi
H
Itoh
Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Souichi
S
Adachi
Tenri Institute of Medical Research, Nara, Japan; and.
Masahiko
M
Hayashida
Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Hiroshi
H
Nakase
Department of Clinical Laboratory Science, Faculty of Health Care, Tenri Health Care University, Nara, Japan; mikepon1308@tenriyorozu-u.ac.jp.
Masaki
M
Ikemoto
D000818:Animals; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D015214:Antigens, Differentiation, Myelomonocytic / Q000276:immunology / Q000378:metabolism*; D019898:Autocrine Communication / Q000276:immunology; D040501:Calgranulin A / Q000276:immunology / Q000378:metabolism*; D040502:Calgranulin B / Q000276:immunology / Q000378:metabolism*; D002846:Chromatography, Affinity; D053339:Edar Receptor / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D053583:Interleukin-1beta / Q000096:biosynthesis / Q000235:genetics; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008297:Male; D011485:Protein Binding; D025941:Protein Interaction Mapping; D034622:RNA Interference; D034741:RNA, Small Interfering; D051381:Rats; D017208:Rats, Wistar; D000067759:Receptor for Advanced Glycation End Products / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D040501:Calgranulin A; D040502:Calgranulin B; D053339:Edar Receptor; D053583:Interleukin-1beta; D034741:RNA, Small Interfering; D000067759:Receptor for Advanced Glycation End Products; D011994:Recombinant Proteins; D051197:Toll-Like Receptor 4; C000593874:Ager protein, rat; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C000594089:IL1B protein, rat; C495347:Tlr4 protein, rat
autocrine; inflammation; receptor-like protein; ulcerative colitis