Hayashi J, Masaka T, Saito I, Ishikawa I
Department of Periodontology, Faculty of Dentistry, Tokyo Medical and Dental University, Bunkyo-ku, Japan.
Infect Immun. 1996 Dec;64(12):4946-51. doi: 10.1128/iai.64.12.4946-4951.1996.
Intercellular adhesion molecule 1 (ICAM-1) is involved in the accumulation and activation of leukocytes in inflammatory diseases such as periodontitis. As reported previously, ICAM-1 is up-regulated on cultured human gingival fibroblasts (HGF) by exposure to lipopolysaccharide (LPS), suggesting a specific LPS recognition mechanism. We therefore investigated the role of CD14, an LPS receptor, in stimulation of HGF by LPS. Cell surface CD14 antigen was not observed on HGF by flow cytometric analysis. In addition, expression of CD14 mRNA in HGF was not detected by reverse transcription-PCR analysis. Since HGF did not express endogenous CD14, we investigated the role of human serum-derived soluble CD14 (sCD14) in ICAM-1 induction on HGF by LPS. The serum-dependent ICAM-1 induction by LPS was observed in HGF. In medium containing human serum, anti-CD14 antibody inhibited ICAM-1 induction on HGF by LPS. Depletion of sCD14 from human serum markedly reduced ICAM-1 expression on HGF in response to LPS. Supplementation of the serum-free medium with sCD14 alone restored the capacity of HGF to respond to LPS. These results show that induction of ICAM-1 in HGF by LPS does not involve binding to cell surface CD14 but is mediated by serum-derived sCD14.
细胞间黏附分子1（ICAM-1）参与诸如牙周炎等炎症性疾病中白细胞的聚集和激活。如先前报道，人牙龈成纤维细胞（HGF）在体外培养时，经脂多糖（LPS）刺激后ICAM-1表达上调，提示存在特定的LPS识别机制。因此，我们研究了LPS受体CD14在LPS刺激HGF过程中的作用。通过流式细胞术分析未在HGF上观察到细胞表面CD14抗原。此外，逆转录-聚合酶链反应（RT-PCR）分析未检测到HGF中CD14 mRNA的表达。由于HGF不表达内源性CD14，我们研究了人血清来源的可溶性CD14（sCD14）在LPS诱导HGF产生ICAM-1中的作用。在HGF中观察到LPS诱导的血清依赖性ICAM-1产生。在含人血清的培养基中，抗CD14抗体抑制LPS诱导HGF产生ICAM-1。从人血清中去除sCD14可显著降低HGF对LPS反应时ICAM-1的表达。仅向无血清培养基中添加sCD14可恢复HGF对LPS的反应能力。这些结果表明，LPS诱导HGF产生ICAM-1不涉及与细胞表面CD14的结合，而是由血清来源的sCD14介导。
