Lysine-specific gingipain promotes lipopolysaccharide- and active-vitamin D3-induced osteoclast differentiation by degrading osteoprotegerin.
Lysine-specific gingipain promotes lipopolysaccharide- and active-vitamin D3-induced osteoclast differentiation by degrading osteoprotegerin.
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DOI：
10.1042/bj20081469
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发表时间：
2009-04-01
期刊：
影响因子：
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通讯作者：
Kamijo R
中科院分区：
文献类型：
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作者：
Yasuhara R;Miyamoto Y;Takami M;Imamura T;Potempa J;Yoshimura K;Kamijo R
牙龈卟啉单胞菌是牙周炎的主要病原体之一，牙周炎是一种以破骨细胞过度吸收牙槽骨为特征的疾病。该细菌产生称为牙龈菌蛋白酶的半胱氨酸蛋白酶，其根据其切割位点特异性分为赖氨酸特异性（Kgp）和精氨酸特异性牙龈菌蛋白酶（Rgps）。在这项研究中，我们研究了牙龈卟啉酶对破骨细胞分化的影响。在小鼠骨髓细胞和成骨细胞的共培养中，Kgp可促进1α，25-二羟维生素D3 [1α，25（OH）2D 3]诱导的多核破骨细胞的形成，而RgpB则不能。生理浓度（0.1 nM）的1α，25（OH）2D 3在100 nM Kgp存在下诱导破骨细胞形成的程度与10 nM 1α，25（OH）2D 3诱导的程度相当。Kgp还增强了由各种微生物成分包括脂多糖诱导的破骨细胞生成。Kgp与1α，25（OH）2D 3或脂多糖联合应用也能增加牙本质切片上形成的吸收陷窝的数量，表明Kgp存在下形成的破骨细胞具有骨吸收活性。增强破骨细胞生成的Kgp与消耗的护骨素在共培养基和蛋白水解活性依赖，因为苄氧羰基-苯丙氨酰-赖氨酰-acycloxyketone，Kgp的抑制剂，完全废除破骨细胞诱导的Kgp。Kgp消化骨保护素，因为其重组蛋白在血清存在下易被Kgp降解。因此，Kgp并没有增加破骨细胞在骨保护素缺乏的成骨细胞和骨髓细胞的共培养。此外，过量的重组骨保护素可消除Kgp增强的破骨细胞生成。这些结果表明，骨保护素的降解是Kgp促进破骨细胞生成的机制之一。
Porphyromonas gingivalis is one of the major pathogens of periodontitis, a condition characterized by excessive alveolar bone resorption by osteoclasts. The bacterium produces cysteine proteases called gingipains, which are classified according to their cleavage-site specificity into lysine-specific (Kgp) and arginine-specific gingipains (Rgps). In this study, we examined the effects of gingipains on osteoclast differentiation. In co-cultures of mouse bone marrow cells and osteoblasts, formation of multinucleated osteoclasts induced by 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] was augmented by Kgp but not by RgpB. A physiological concentration (0.1 nM) of 1α,25(OH)2D3 induced the osteoclast formation in the presence of 100 nM Kgp to the extent comparable to that induced by 10 nM 1α,25(OH)2D3. Kgp also enhanced osteoclastogenesis induced by various microbial components including lipopolysaccharide. Combined use of Kgp and 1α,25(OH)2D3 or lipopolysaccharide also increased the number of resorption pits developed on dentin slices, indicating the osteoclasts formed in the presence of Kgp possess bone-resorbing activity. The enhanced osteoclastogenesis by Kgp was correlated with a depletion of osteoprotegerin in co-culture media and proteolytic activity-dependent, since benzyloxycarbonyl-phenylalanyl-lysyl-acycloxyketone, an inhibitor of Kgp, completely abolished osteoclastogenesis induced by Kgp. Kgp digested osteoprotegerin, since its recombinant protein was susceptible to degradation by Kgp in the presence of serum. As a result, Kgp did not augment osteoclastogenesis in co-cultures of osteoprotegerin-deficient osteoblasts and bone marrow cells. In addition, enhanced osteoclastogenesis by Kgp was abolished by excess amount of recombinant osteoprotegerin. These findings suggest that degradation of osteoprotegerin is one of the mechanisms underlying promotion of osteoclastogenesis by Kgp.