Ogura N, Nagura H, Abiko Y
Department of Oral Surgery, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
J Periodontol. 1999 Apr;70(4):402-8. doi: 10.1902/jop.1999.70.4.402.
Urokinase-type plasminogen activator receptor (uPAR) presenting on the cell surface with glycosylphosphatidylinositol (GPI) anchor is a key component in the plasminogen activator (PA)-plasmin system and plays a critical role in extracellular matrix degradation. It is believed that uPAR serves to localize and accelerate this generation system. In this study, we examined the levels of both uPA and uPAR in human gingival fibroblasts treated with Porphyromonas gingivalis lipopolysaccharide (LPS).
Human gingival fibroblasts from the seventh to tenth doubling passages were plated at 5x10(4) cells per well in 24-well plates. The confluent-stage cells were cultured for 24 hours in alpha-MEM medium containing 2% fetal calf serum, after which they were incubated with P. gingivalis LPS. PA activity was measured using plasminogen and plasmin substrate S2251.
PA activity in the cell lysate was increased by LPS and reached maximum at 1 microg/ml LPS after being incubated for 8 hours. PA activity released by phosphatidylinositol-specific phospholipase C, which detaches the GPI anchor, was also increased by LPS. The activity was inhibited by amiloride, which is a specific inhibitor for uPA. LPS increased the protein and mRNA levels of both uPA and uPAR in gingival fibroblasts.
These findings suggest that increase of the uPAR level by LPS may play an important role in the progression of periodontal diseases through pericellular proteolysis.
尿激酶型纤溶酶原激活物受体（uPAR）通过糖基磷脂酰肌醇（GPI）锚定在细胞表面，是纤溶酶原激活物（PA）-纤溶酶系统的关键组成部分，在细胞外基质降解中起关键作用。据信uPAR有助于定位和加速这一生成系统。在本研究中，我们检测了用牙龈卟啉单胞菌脂多糖（LPS）处理的人牙龈成纤维细胞中uPA和uPAR的水平。
将处于第7至10代倍增期的人牙龈成纤维细胞以每孔5×10⁴个细胞接种于24孔板中。汇合期细胞在含2%胎牛血清的α-MEM培养基中培养24小时，之后与牙龈卟啉单胞菌LPS孵育。使用纤溶酶原和纤溶酶底物S2251测量PA活性。
LPS使细胞裂解物中的PA活性增加，孵育8小时后，在1μg/ml LPS时达到最大值。可使GPI锚定脱离的磷脂酰肌醇特异性磷脂酶C释放的PA活性也因LPS而增加。该活性被阿米洛利抑制，阿米洛利是uPA的特异性抑制剂。LPS增加了牙龈成纤维细胞中uPA和uPAR的蛋白质及mRNA水平。
这些发现表明，LPS使uPAR水平升高可能通过细胞周围蛋白水解在牙周疾病进展中起重要作用。
