Masaka T, Hayashi J, Ishikawa I
Department of Periodontology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
J Periodontol. 1999 Jul;70(7):772-8. doi: 10.1902/jop.1999.70.7.772.
Intercellular adhesion molecule-1 (ICAM-1) is involved in the accumulation and activation of leukocytes in inflammatory sites through binding to beta2 integrins expressed on leukocytes. We investigated whether or not lipopolysaccharide (LPS) derived from the periodontopathic bacterium Porphyromonas gingiualis affects ICAM-1 expression on human gingival fibroblasts (HGF). CD14 is a receptor for LPS on monocytes and macrophages and is also present in serum as a soluble protein. We further examined the effects of serum and soluble CD14 (sCD14) on ICAM-1 expression in HGF stimulated with P. gingivalis LPS.
HGF were prepared from explants of human gingival tissues and incubated in 96-well culture plates before LPS stimulation. LPS derived from Escherichia coli O55:B5 and P. gingivalis ATCC 33277 LPS were employed. sCD14 was purified from normal human serum (NHS) by affinity chromatography using an anti-CD14 monoclonal antibody. ICAM-1 expression on HGF was measured by a cell enzyme-linked immunosorbent assay.
P. gingivalis LPS induced ICAM-1 on HGF in a dose-dependent manner in the presence of either 10% fetal calf serum or 2% NHS. The ability of P. gingivalis LPS to induce ICAM-1 was comparable to that of LPS from E. coli at high LPS concentrations. In the absence of NHS, ICAM-1 induction was negligible in HGF stimulated with P. gingivalis LPS, reaching a maximum at 2% NHS. The ICAM-1 expression induced by P. gingivalis LPS was inhibited by a monoclonal antibody to CD14. Supplementation of serum-free medium with sCD14 alone restored the capacity of HGF to respond to P. gingivalis LPS.
These results indicate that P. gingivalis LPS induces ICAM-1 expression in HGF in an sCD14-dependent manner. The overexpression of ICAM-1 on fibroblasts in gingiva induced by P. gingivalis LPS seems to be involved in the retention of inflammatory cells in periodontitis lesions.
细胞间黏附分子-1（ICAM-1）通过与白细胞表面表达的β2整合素结合，参与炎症部位白细胞的聚集和激活。我们研究了源自牙周病原菌牙龈卟啉单胞菌的脂多糖（LPS）是否会影响人牙龈成纤维细胞（HGF）上ICAM-1的表达。CD14是单核细胞和巨噬细胞上LPS的受体，在血清中也以可溶性蛋白形式存在。我们进一步研究了血清和可溶性CD14（sCD14）对牙龈卟啉单胞菌LPS刺激的HGF中ICAM-1表达的影响。
从人牙龈组织外植体中制备HGF，并在LPS刺激前在96孔培养板中培养。使用源自大肠杆菌O55:B5的LPS和牙龈卟啉单胞菌ATCC 33277 LPS。通过使用抗CD14单克隆抗体的亲和色谱法从正常人血清（NHS）中纯化sCD14。通过细胞酶联免疫吸附测定法测量HGF上ICAM-1的表达。
在存在10%胎牛血清或2%NHS的情况下，牙龈卟啉单胞菌LPS以剂量依赖性方式诱导HGF上的ICAM-1。在高LPS浓度下，牙龈卟啉单胞菌LPS诱导ICAM-1的能力与大肠杆菌LPS相当。在没有NHS的情况下，牙龈卟啉单胞菌LPS刺激的HGF中ICAM-1的诱导作用可忽略不计，在2%NHS时达到最大值。牙龈卟啉单胞菌LPS诱导产生的ICAM-1表达被抗CD14单克隆抗体抑制。仅用sCD14补充无血清培养基可恢复HGF对牙龈卟啉单胞菌LPS作出反应的能力。
这些结果表明，牙龈卟啉单胞菌LPS以sCD14依赖性方式诱导HGF中ICAM-1的表达。牙龈卟啉单胞菌LPS诱导牙龈成纤维细胞上ICAM-1的过表达似乎与牙周炎病变中炎症细胞的滞留有关。
