叉头转录因子-1与骨代谢关系的研究进展

叉头转录因子-1（FoxO1）可调控细胞增殖、葡萄糖异生、能量代谢和氧化应激等生物学过程,近年来研究表明,其在骨重塑过程中也发挥着重要的作用,影响机体骨量。其主要通过调控成骨细胞形成新骨,破骨细胞吸收矿化骨基质和前体细胞的分化增殖,影响骨代谢过程,调控机体骨量。本文通过对FoxO1在骨代谢中的研究进行回顾,对其在骨代谢中的作用途径和机制进行综述。     

Localization and function of the accessory protein Mfa3 in Porphyromonas gingivalis Mfa1 fimbriae

The fimbriae of Porphyromonas gingivalis, the causative agent of periodontitis, have been implicated in various aspects of pathogenicity, such as colonization, adhesion and aggregation. Porphyromonas gingivalis ATCC 33277 has two adhesins comprised of the FimA and Mfa1 fimbriae. We characterized the PGN0289 (Mfa3) protein, which is one of the three accessory proteins of Mfa1 fimbriae in P. gingivalis. The Mfa3 protein was present in two different sizes, 40 and 43 kDa, in the cell. The 43‐kDa and 40‐kDa Mfa3 were detected largely in the inner membrane and the outer membrane, respectively. Purified Mfa1 fimbriae contained the 40‐kDa Mfa3 alone. Furthermore, the 40‐kDa Mfa3 started with the Ala⁴⁴ residue of the deduced amino acid sequence, indicating that the N‐terminal region of the nascent protein expressed from the mfa3 gene is processed in the transport step from the inner membrane into fimbriae. Immuno‐electron microscopy revealed that Mfa3 localized at the tip of the fimbrial shaft. Interestingly, deletion of the mfa3 gene resulted in the absence of other accessory proteins, PGN0290 and PGN0291, in the purified Mfa1 fimbriae, suggesting that Mfa3 is required for integration of PGN0290 and PGN0291 into fimbriae. A double mutant of mfa3 and fimA genes (phenotype Mfa1 plus, FimA minus) showed increased auto‐aggregation and biofilm formation similar to a double mutant of mfa1 and fimA genes (phenotype Mfa1^–, FimA^–). These findings suggest that the tip protein Mfa3 of the Mfa1 fimbriae may function in the integration of accessory proteins and in the colonization of P. gingivalis.     

Green tea catechins potentiate the effect of antibiotics and modulate adherence and gene expression in Porphyromonas gingivalis

ObjectivesA number of studies have brought evidence that green tea catechins may contribute to periodontal health. The objective of this study was to investigate the ability of a green tea extract and its principal constituent epigallocatechin-3-gallate (EGCG) to potentiate the antibacterial effects of antibiotics (metronidazole, tetracycline) against Porphyromonas gingivalis, and to modulate the adherence to oral epithelial cells and expression of genes coding for virulence factors and the high temperature requirement A (HtrA) stress protein in P. gingivalis.MethodsA broth microdilution assay was used to determine the antibacterial activity of the green tea extract and EGCG. The synergistic effects of either compounds in association with metronidazole or tetracycline were evaluated using the checkerboard technique. A fluorescent assay was used to determine bacterial adherence to oral epithelial cells. The modulation of gene expression in P. gingivalis was evaluated by quantitative RT-PCR. The Vibrio harveyi bioassay was used for monitoring quorum sensing inhibitory activity.ResultsThe MIC values of the green tea extract on P. gingivalis ranged from 250 to 1000 μg/ml, while those of EGCG ranged from 125 to 500 μg/ml. A marked synergistic effect on P. gingivalis growth was observed for the green tea extract or EGCG in combination with metronidazole. Both the green tea extract and EGCG caused a dose-dependent inhibition of P. gingivalis adherence to oral epithelial cells. On the one hand, green tea extract and EGCG dose-dependently inhibited the expression of several P. gingivalis genes involved in host colonization (fimA, hagA, hagB), tissue destruction (rgpA, kgp), and heme acquisition (hem). On the other hand, both compounds increased the expression of the stress protein htrA gene. The ability of the green tea extract and EGCG to inhibit quorum sensing may contribute to the modulation of gene expression.ConclusionsThis study explored the preventive and therapeutic potential of green tea catechins against periodontal disease. In addition to inhibit growth and adherence of P. gingivalis, a green tea extract and its main constituent EGCG was found to decrease the expression of genes coding for the major virulence factors.     

Role of p38 mitogen-activated protein kinase pathway in Porphyromonas gingivalis lipopolysaccharide-induced VCAM-1 expression in human aortic endothelial cells

Background: Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) has been reported to induce the expression of vascular cell adhesion molecule‐1 (VCAM‐1) in vascular endothelial cells. This finding suggests the potential roles for Pg in the pathogenesis of atherosclerosis. However, the mechanism involved in Pg LPS‐induced VCAM‐1 production in endothelial cells remains unclear. Methods: Quantitative real‐time polymerase chain reaction and Western blotting were used, respectively, to investigate the mRNA expression and protein production of VCAM‐1 in human aortic endothelial cells (HAECs) induced by Pg LPS. The involvement of the p38 mitogen‐activated protein kinase (p38 MAPK) cell signaling pathway in VCAM‐1 expression was investigated by assays with specific inhibitors. Results: Pg LPS–induced expression in HAECs of VCAM‐1 occurred in a dose‐ and time‐dependent manner. In addition, the p38 MAPK inhibitor (SB 203580) significantly attenuated Pg LPS–induced VCAM‐1 expression. Conclusion: Activation of p38 MAPK is at least partially involved in Pg LPS–induced VCAM‐1 expression in HAECs, which may contribute to the acceleration of atherosclerosis.     

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目的 探讨牙龈卟啉单胞菌(Porphyromonas gingivalis,P.gingivalis)W83、ATCC33277刺激人牙周膜成纤维细胞(HPDLFs)分泌基质金属蛋白酶-1(MMP-1)、金属蛋白酶组织抑制剂-1(TIMP-1)的变化.方法 本研究于2010年9月至2011年6月在中国医科大学口腔医学院中心实验室进行.将P.gingivalis W83、ATCC33277作用于HPDLFs0、6、12、24、48h后,运用酶联免疫吸附法(ELISA)检测细胞上清液中MMP-1、TIMP-1质量浓度变化,并计算MMP-1/TIMP-1值.结果 P.gingivalis感染HPDLFs的MMP-1和TIMP-1表达均增强,并呈时间依赖性;且MMP-1/TIMP-1值明显高于未感染的对照组(P＜0.05).P.gingivalis W83感染后MMP-1/TIMP-1值明显高于P.gingivalis ATCC33277(P＜ 0.05).结论 P.gingivalis具有促进HPDLFs分泌MMP-1、TIMP-1的作用,且可造成牙周组织破坏;P.gingivalis W83降解细胞外基质的能力高于P.gingivalisATCC33277.     

高速泳动族蛋白盒1与正畸牙移动的相关性研究

正畸牙受矫治力作用后,其牙周组织将发生一系列的生物化学反应,多种细胞因子和激素参与了反应的整个过程。高速泳动族蛋白盒1(HMGB1)是一种重要的晚期炎症因子,参与骨组织改建并与成纤维细胞相互作用,据此推测其可能参与正畸牙移动过程中的牙周组织改建。本文就HMGB1与炎症反应、骨组织改建、成纤维细胞、牙周炎,正畸牙移动的生物学基础等研究现状作一综述。     

Identification of immunoreactive epitopes of the Porphyromonas gingivalis heat shock protein in periodontitis and atherosclerosis

Choi J, Lee S‐Y, Kim K, Choi B‐K. Identification of immunoreactive epitope of Porphyromonas gingivalis heat shock protein peptide in periodontitis and atherosclerosis. J Periodont Res 2011; 46: 240–245. © 2011 John Wiley & Sons A/S Background and Objective: Heat shock protein 60 (HSP60) of Porphyromonas gingivalis, a major periodontal pathogen, might be a trigger molecule linking infectious periodontitis and autoimmune atherosclerosis. The aim of this study was to identify the peptide specificity of anti‐P. gingivalis HSP60 monoclonal antibodies and their cross‐reactivity with bacterial and human HSPs. Their specific immunoreactivity to periodontal or atherosclerotic lesions was also investigated. Methods: Twenty patients with chronic periodontitis and 20 atherosclerosis patients who had undergone surgical intervention for atheromatous plaques with evidence of ongoing periodontal disease, were selected. Synthetic peptide 19 ((TLVVNRLRGSLKICAVKAPG)‐specific T‐cell lines were established from inflamed gingiva and atheromatous plaque and the phenotypes and cytokine profiles were characterized. Results: Thirty per cent of periodontitis patients and 100% of atherosclerosis patients reacted positively to cross‐reactive peptide 19 from both P. gingivalis and human HSP60. The peptide 19‐specific T‐cell lines demonstrated the phenotype characteristic of helper T cells (CD4⁺) but did not express CD25 or FOXP3. The interleukin‐10 levels were elevated significantly in the peptide 19 T‐cell line. Conclusion: Synthetic peptide 19 of P. gingivalis HSP60 is an immunoreactive epitope in the periodontitis–atherosclerosis axis.     

牙龈卟啉单胞菌对脐静脉血管内皮细胞表达IL-8和MCP-1 mRNA的影响

目的：在转录水平上观察牙龈卟啉单胞菌对脐静脉血管内皮细胞（human umbilical vein endothelial cells,HUVECs）表达白细胞介素-8（IL-8）和单核细胞趋化蛋白-1（MCP-1）的影响。方法：厌氧培养Pg，原代培养HUVECs，RNA抽提，逆转录-聚合酶链式反应（RT-PCR）和mRNA比色定量法检测IL-8和MCP-1基因表达。结果：HUVECs基础表达IL-8和MCP-1mRNA,Pg以剂量依赖的方式增强IL-8和MCP-1mRNA的表达，Pg感染后1hIL-8mRNA开始增高，3h达到高峰，并持续到5h。而MCP-1的mRNA从Pg感染后1h开始增高，3h达到高峰，5h出现下降趋势。结论：Pg在转录水平上增强UHUVECs表达IL-8和MCP-1，这种上调作用可能是牙周病早期基因水平调控炎症细胞募集的重要因素，可能是牙周疾病的炎症反应和免疫反应中主要调控机制之一。     

Effect of intermittent PTH administration in the periodontitis-associated bone loss in ovariectomized rats

OBJECTIVE: Parathyroid hormone intermittent administration has been considered to treat bone mass decrease in osteoporotic individuals. The present study evaluates whether PTH can affect alveolar bone loss in ovariectomized rats, since estrogen deficiency has been proposed as a risk factor for periodontal disease. DESIGN AND METHODS: Thirty female rats were set in groups: ovariectomized (Ovx) and Sham operated. Ovx were divided in two groups: Ovx-PTH (1-34) treated and Ovx, which received vehicle. After 1 week, cotton ligature was placed around one lower first molar of all animals to induce periodontal disease. Ovx treated received PTH doses of 40 microg/kg, three times a week for 30 days. After that, the animals were sacrificed, the mandibles extracted, X-rayed and samples prepared for histological evaluation. Histomorphometry was performed using image analyzer software. Scanning electron microscopy (SEM) of the tibias was also performed in all animals to evaluate possible changes in bone structure caused by the estrogen deficiency. Optical densities of the radiographs were measured by aluminum step-wedge equivalent thickness. RESULTS: Histomorphomery indicated the anabolic PTH effect in ovariectomized rats with significant inhibition of periodontitis manifestation (p<0.05) thus neutralizing the periodontitis inductor effects. The photo densitometry showed a lower mandibular optical density in the ovariectomized group that did not receive PTH (p<0.05). SEM image confirmed the early effect of estrogen deficiency in osseous tissue and PTH anabolic effect. CONCLUSION: PTH systemic intermittent administration was able to reduce alveolar bone loss in ovariectomized rats, despite the presence of a periodontal disease inductor and estrogen deficiency.     

牙龈卟啉单胞菌来源的脂多糖通过X盒结合蛋白1调控脂肪细胞胰岛素信号通路的机制研究

探讨内质网应激（ERS）关键信号分子X盒结合蛋白1（XBP1）在牙周炎致病菌牙龈卟啉单胞菌（P. gingivalis）来源的脂多糖（LPS）刺激下对脂肪细胞胰岛素信号通路的影响。     

多粘菌素B和热处理对牙龈卟啉单胞菌诱导ECHUV产生sICAM-1的影响

目的：观察多粘菌素B和热处理对牙龈卟啉菌诱导人类脐静脉血管内皮细胞（endothelial cells of human umbilical vein,ECHUV）产生可溶性细胞间粘附分子－1（soluble intercellular adhesion molecule-1,sICAM-1）的影响，以探讨P．gingivalis诱导ECHUV产生sICAM-1的有效部位。方法：采用酶联免疫吸附试验（enzyme-linked immunosorbent assay,ELISA）测定培养上清中sICAM-1的含量。结果：P.gingivalis、大肠杆菌脂多糖（LPS）和肿瘤坏死因子－α（TNF－α）强烈诱导ECHUV产生sICAM-1，多粘菌素B明显抑制大肠杆菌LPS的诱导作用，热处理完全废除了TNF－α的作用，而这两种方法都不能降低P.gingivalis对ECHUV产生sICAM-1的影响。另外，P.gingivalis毒力株W83的诱导强度明显高于非毒力株ATCC33277。结论：P.gingivalis可能通过LPS以外的耐热的有效位点诱导ECHUV产生sICAM-1，这一位点可能与P.gingivalis的有效毒力因子有关。     

Differential expression of interleukin-8 and intercellular adhesion molecule-1 by human gingival epithelial cells in response to Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis infection

Little is known regarding the molecules expressed by gingival epithelial cells that are involved in initiating and maintaining inflammation following the interaction with periodontal pathogens. Thus, we investigated the effect of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis infection on the expression of neutrophil chemoattractant interleukin 8 (IL-8) and the adhesion molecule intercellular adhesion molecule-1 by gingival epithelial cells. The data revealed that both IL-8 and intercellular adhesion molecule-1 expression increased after infection with A. actinomycetemcomitans (IL-8: 2- to 7-fold; intercellular adhesior molecule-1: 2.5- to 3.7-fold). IL-8 secretion reached a maximal level 6 h after the infection and the expression subsequently decreased to basal level. The increased cell surface intercellular adhesion molecule-1 expression started at 4 h after infection and reached a maximal level 14 h after the infection. In contrast, the expression of both molecules rapidly decreased 2 h after challenge with P. gingivalis. This opposite influence of A. actinomycetemcomitans and P. gingivalis infection on the expression of IL-8 and intercellular adhesion molecule-1 by gingival epithelial cells suggests that A. actinomycetemcomitans infection may initiate the recruitment of neutrophils, whereas the P. gingivalis infection may retard this process and therefore demonstrate a distinct perspective of virulence.     

Periodontal conditions and prevalence of putative periodontopathogens and Candida spp. in insulin-dependent type 2 diabetic and non-diabetic patients with chronic periodontitis--a pilot study

Objectives

The aims of this study were to evaluate periodontal conditions and identify the presence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia, and four different species of Candida (C. albicans, C. dubliniensis, C. glabrata and C. tropicalis) in periodontal pockets and furcation sites of insulin-dependent type 2 diabetic and non-diabetic patients with generalised chronic periodontitis.

Design

Clinical parameters, including oral status assessed using plaque index, gingival index, probing depth, gingival recession and clinical attachment level and systemic conditions with fasting glucose level or glycosylated haemoglobin were measured in diabetic and non-diabetic patients with chronic periodontitis. Samples of subgingival biofilm were obtained from the periodontal pockets and furcation sites and submitted to phenol-chloroform DNA extraction and PCR analysis using specific primers.

Results

Clinical conditions of diabetic and non-diabetic patients were similar, without statistical differences in both periodontal indexes and glucose levels (p > 0.05). Diabetics had a higher prevalence of Candida spp., mainly C. albicans and C. dubliniensis, and a lower frequency of T. forsythia, when compared to non-diabetic patients, for both periodontal sites. C. glabrata and C. tropicalis were not found in periodontal pockets and furcation sites of non-diabetic patients.

Conclusion

The results demonstrated a strong colonisation of Candida spp. in the periodontal sites of diabetic patients that have generalised chronic periodontitis with a higher prevalence of C. dubliniensis followed by C. albicans.     

DMP1、Runx2在小鼠下颌第一磨牙萌出过程中的免疫学定位

目的 研究小鼠下颌第一磨牙萌出过程中牙本质基质蛋白1（DMP1）和Runt相关转录因子2（RUNX2）的表达, 并探索其表达与牙萌出之间的关系。 方法 分离出生后1 d至14 d小鼠的下颌骨,连续切片,偶氮卡红苯胺蓝染色显示磨牙萌出过程骨胶原形成情况,切片原位杂交法分析DMP1及RUNX2 mRNA在牙齿及周围组织的表达与分布,免疫组化法显示DMP1和RUNX2蛋白的表达与分布。结果 冠方骨组织中骨胶原形成在P5 d出现高峰,以后呈逐渐减少的趋势;根方骨胶原形成在整个萌出过程中一直呈活跃状态,在P9 d出现高峰。DMP1表达越丰富,骨胶原形成越多,成骨活动越活跃。结论 下颌第一磨牙萌出过程中,根方成骨活动一直很活跃,DMP1的表达与根方成骨活动参与了小鼠第一磨牙的萌出过程。     

Effect of lipopolysaccharide from Porphyromonas gingivalis on prostaglandin E2 and interleukin-1β release from rat periosteal and human gingival fibroblasts in vitro

Lipopolysaccharide (LPS) was extracted from Porphyromonas gingivalis (W83) by the Westphal procedure, nuclease-digested and ultracentrifuged. Fibroblasts were obtained from human gingival tissue and rat periosteum, grown to confluence then stimulated in serum-free medium with 0.1, 1.0 and 10.0μg/ml LPS. The levels of prostaglandin E₂ (PGE₂) and interleukin-1β (IL-1β) released were measured after 2, 4 and 6 d by specific radioimmunoassays. Unstimulated gingival fibroblasts produced low levels of PGE₂ (24.5 ± 1.5 (SD) ng/ml) and IL-1β (0.34 ± 0.29 ng/ml). LPS stimulated statistically significant dose-related increases hi PGE₂ and IL-1β at the concentrations of LPS tested. At 10.0μg/ml, LPS-stimulated fibroblasts produced 363.5 ± 40.3 ng/ml PGE, and 1.81±0.1 ng/ml IL-1β in 6 d. These results demonstrate that LPS from P. gingivalis is capable of stimulating PGE, and IL-1β release from fibroblasts. This would appear to be an additional mechanism by which LPS can induce tissue breakdown in periodontal disease.