The study of an effect of Porphyromonas gingivalis heat shock protein on bone resorption

牙龈卟啉单胞菌（牙龈卟啉单胞菌）是一种革兰氏阴性细菌，与成人牙周炎的病理有关，涉及牙槽骨的破坏。伴侣蛋白（cpns）是细胞内的寡聚蛋白复合物，以催化的方式折叠和再折叠蛋白质。Cpns也是感染性疾病的主要免疫原，因为有证据表明大肠杆菌GroEL和分枝杆菌cpn60s可以诱导细胞因子合成，并刺激细胞因子依赖性骨吸收。我们利用14日龄小鼠胚胎颅骨骨细胞培养系统，研究了牙龈假单胞菌脂多糖或纤布蛋白等成分对骨吸收的作用机制。然而，关于牙龈卟啉菌伴侣蛋白（Pcpn） 60 （GroEL）在骨吸收中的作用却知之甚少。在本研究中，我们发现P. gingivalis GroEL在γδT细胞存在下刺激骨吸收被骨保护素（osteoprotegerin， OPG）抑制。通过M-CSF （10ng/ml）和次优剂量RANKL处理的前体细胞（Mac-1（+）、c-Fms（+）、RANK(+)）与γδT细胞（αβT细胞）共培养，观察牙龈假单胞菌GroEL刺激下破骨细胞的形成。这些数据表明，如果从牙龈假单胞菌中释放GroEL，并在牙槽骨或牙周组织中增加γδT细胞，则可以诱导破骨细胞的形成。

Porphyromonas gingivalis (P. gingivalis) is a Gram-negative bacterium implicated in the pathology of adult periodontitis, an involving destruction of alveolar bone. Chaperonins (cpns) are intracellular oligomeric protein complexes that fold and refold proteins in a catalytic manner. Cpns are also major immunogen in infectious diseases, because of some evidences that Escherichia coli GroEL and Mycobacterial cpn 60s can induce cytokine synthesis, and stimulate cytokine-dependent bone resorption. We have shown mechanisms of bone resorption by components of P. gingivalis such as lipopolysaccharide or fimbrillin by using 14-day-old mouse embryonic calvarial bone cell culture system. However, little is known concerning P. gingivalis chaperonin (Pcpn) 60 (GroEL) on bone resorption. In the present study, we show that P. gingivalis GroEL stimulates bone resorption in the presence of γδT cells was inhibited by osteoprotegerin (OPG). The osteoclast formation by stimulation of P. gingivalis GroEL was observed by coculture between precursor cells (Mac-1(+), c-Fms(+), RANK(+)) treated with both M-CSF (10ng/ml) and suboptimal dose of RANKL, and γδT cells, but not αβT cells. These data suggest that if GroEL was released from P. gingivalis and γδT cells was increased in alveolar bone or periodontal tissue, it could induce osteoclast formation.