Lack of association between chronic periodontitis and the Toll-like receptor 4 gene polymorphisms in a Czech population

BACKGROUND AND OBJECTIVE: Periodontitis is a bacterially induced chronic inflammatory disease and a major cause of tooth loss among adults. Toll-like receptors are signal molecules essential for the cellular response to bacterial cell wall components. The aim of this study was to investigate relationships between chronic periodontitis and variations in the TLR4 gene. MATERIAL AND METHODS: A total of 171 patients with chronic periodontitis and 218 unrelated controls were genotyped for the Asp299Gly (896A>G) and Thr399Ile (1196C>T) polymorphisms of the TLR4 gene. RESULTS: Both variants were in nearly complete linkage disequilibrium. No homozygotes for the less common alleles, 299Gly and 399Thr, respectively, were found. The prevalence of the Asp299Gly and the Thr399Ile heterozygotes was 5.3% and 5.0% in controls, and 7.0% and 7.0% in periodontitis patients. CONCLUSION: In conclusion, TLR4 gene polymorphisms were not significantly associated with the susceptibility to, or severity of, chronic periodontitis in our population.     

年龄对小鼠腹腔巨噬细胞TLR2/4表达水平及功能的影响

目的：观察不同年龄组小鼠腹腔巨噬细胞Toll样受体2/4（TLR2/4）表达水平的差别,以及该细胞在脂多糖（LPS）刺激下,炎症因子TNF-α分泌水平的差别。方法：采用real-time PCR和流式细胞技术,检测低龄组和高龄组小鼠腹腔巨噬细胞TLR2/4 mRNA和蛋白表达水平的差异;同时检测1μg/mL大肠杆菌（E.coli）LPS或1mg/L牙龈卟啉单胞菌（P.gingivalis）LPS刺激后,两组细胞TLR2/4表达水平的变化;采用ELISA技术检测炎症因子TNF-α分泌水平的变化。结果：刺激前,两组细胞TLR2/4 mRNA和蛋白表达水平均无明显差别。E.co-li LPS或P.gingivalis LPS刺激后,低龄组细胞TLR2/4mRNA和蛋白表达水平均明显高于高龄组（P〈0.05）,其分泌的TNF-α水平也显著高于高龄组（P〈0.05）。结论：年龄对小鼠腹腔巨噬细胞TLR2/4表达水平没有显著影响,但增龄性变化可能导致TLR2/4功能的减退。     

Melatonin and cancer: current knowledge and its application to oral cavity tumours

J Oral Pathol Med (2011) 40 : 593–597 Background: Melatonin (MLT) is a molecule secreted by the pineal gland in cyclical periods. In mammals, MLT is involved in physiological processes, such as sleep/wake regulation in the circadian cycle. It has antioxidant and anti‐inflammatory properties, functions as an immunomodulator, and stimulates bone metabolism. MLT is also involved in tumour processes in breast, prostate, liver, and bone cancers, among others, and in oral cavity tumours like epidermoid carcinoma. We are gradually increasing our knowledge of the underlying mechanism of MLT action in the aforementioned tumour processes, in which MT1, MT2, MT3, and RZR receptors appear to play a highly important role. These receptors belong to a large family of G‐protein‐coupled transmembrane receptors, some of which have been linked to melatonin’s anticancer action, to tumour growth, and to prognosis. The objective of this article is to provide a clear review of research into the range of MLT functions, focusing specifically on MT receptors. We aim to contribute interesting, new approaches to research into oral cavity tumours. Methods: An extensive review of the research literature was conducted using PubMed, Science Direct, ISI Web of Knowledge, and the Cochrane base. Results: This study highlights the growing importance of MLT in the prognosis and treatment of certain tumours, including epidermoid carcinoma in the oral cavity. Moreover, it opens up a highly original, encouraging line of research in the field of tumours. Conclusions: MLT contributes to protecting the oral cavity from tissue damage caused by receptor action. Experimental evidence suggests that it may be useful in the treatment and prognosis of tumour processes in the oral cavity.     

Toll-like receptors 2 and 5 in human gingival epithelial cells co-operate with T-cell cytokine interleukin-17

Background/aim:  Periodontitis begins as the result of perturbation of the gingival epithelial cells caused by subgingival bacteria interacting with the epithelial cells via pattern recognition receptors. Toll-like receptors (TLRs) have been shown to play an important role in the recognition of periodontal pathogens so we have studied the interaction of TLR ligands with TLR2 and TLR5 for cytokine production in the cultures of gingival epithelial cells.
Methods:  Immunohistochemistry was used for the localization of TLR2 and TLR5 in tissue specimens. Enzyme-linked immunosorbent assays were performed to detect the levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), released from gingival epithelial cell cultures following stimulation with TLR ligand alone or in combination with IL-17.
Results:  Both TLR2 and TLR5 were increased in periodontitis (2128 ± 159 vs. 449 ± 59 and 2456 ± 297 vs. 679 ± 103, respectively, P  < 0.001) including gingival epithelial cells that stained strongly. Cultured gingival epithelial cells stimulated with their respective ligands (HKLM, a TLR2 ligand that is also found in Porphyromonas gingivalis , and flagellin, a TLR5 ligand that is also found in Treponema denticola ) produced both IL-1β and TNF-α. To mimic T-cell help, IL-17 was added. This further greatly enhanced TLR ligand-induced IL-1β ( P  < 0.001) and TNF-α ( P  < 0.01) production.
Conclusions:  These findings show how pathogen-associated molecular patterns, shared by many different periodontopathogenic bacteria, stimulate the resident gingival epithelial cells to inflammatory responses in a TLR-dependent manner. This stimulation may be particularly strong in periodontitis and when T helper type 17 cells provide T-cell help in intercellular cooperation.     

The expression of NMDA receptor 1 is associated with clinicopathological parameters and prognosis in the oral squamous cell carcinoma

BACKGROUND: Glutamate activates the N-methyl-d-aspartate (NMDA) receptors and this receptor is involved in the proliferation and migration of various tumour cells in vitro. However, the relationship between NMDA receptor expression and clinical parameters in cancer patients is unclear. Therefore, NMDA receptor 1 (NMDAR1) expression along with its clinical significance was examined in patients with oral squamous cell carcinoma (OSCC). METHODS: Eighty-one tumour specimens from OSCC patients were used to determine the NMDAR1 expression level by immunohistochemical staining. The control was obtained from a matched normal adjacent mucosa. The cases were considered to be positive if reactivity was displayed in >25% of the cells. RESULTS: The NMDAR1 reactivity was positive in 50 of 81 cases, while it was negative in the control. NMDAR1 expression was significantly associated with a lymph node metastasis (P = 0.008), the tumour size (P < 0.001), and the cancer stage (P = 0.034). The patients whose tumours expressed NMDAR1 had a significantly poorer survival than the patients who were NMDAR1-negative (log-rank = 6.45, d.f. = 1, P = 0.011). CONCLUSIONS: The NMDAR1 overexpression was significantly associated with the prognosis-related factors. Therefore, it might be one of the prognostic markers of OSCC.     

Expression and intracellular localization of progesterone receptors in cultured human gingival fibroblasts

OBJECTIVE: The aim of this immunocytochemical study was to characterize the expression and distribution of the progesterone receptor (PR) and estrogen receptor (ER) in gingival fibroblasts using culture cells derived from people at various ages. BACKGROUND: The reaction of female hormones is tissue or cell specific, and receptor availability in the cell is one of the major causes for the different reactions. Gingiva is a target tissue for female hormones; however, the characteristics of PR and ER in both the fibroblasts and the other component cells remain largely unknown. MATERIALS: Gingival tissue was obtained from six people at various ages and culture fibroblasts were established. At least three passages of each cell line were strained for PR and ER with monoclonal antibodies (Clone 1A6, Clone 1D5, respectively). RESULTS: PR positive cells were detected in all six cell lines through early passages to late ones, but ER were only observed in two of six samples with faint reactions. The staining intensity for PR was greater than for ER, but less than that shown in the MCF-7 breast cancer cells, positive control. In every positive control test, ER reactivity was equal to or higher than that of PR. During the interphase, significantly fewer positive fibroblasts occurred compared with negative fibroblasts, and positive nuclei were even fewer. Meanwhile, most of the mitotic cells were PR positive, showing intense localization around chromosomes and on microtubules. These findings suggest that gingival fibroblasts are fundamentally capable of expressing PR and transmit the signal to target genes. CONCLUSIONS: The present study may conclude that in either gender or at any age, gingival fibroblasts express PR rather low in level and do not necessarily localize PR in a nuclear dominant fashion, which is an essential feature for reproductive organ cells. The poor ER reactivity shown in the gingival fibroblasts was discussed in view of the receptor subtype.     

Toll样受体2和4在细胞成骨向分化中的作用

Toll样受体（TLR）4是人类发现的第一个TLR相关蛋白质,主要介导格兰阴性细菌的免疫过程。TLR2具有相对广泛的配体特异性,可识别多种病原体相关分子模式,协助TLR4参与人体内对脂多糖的反应。研究显示, TLR2和TLR4参与多种细胞成骨向分化的调控。譬如TLR2和TLR4即可通过促进主动脉瓣间质细胞的成骨向分化参与主动脉瓣钙化过程,也可通过上调冠状动脉内皮细胞中骨形态发生蛋白2的表达参与冠状动脉粥样硬化,还可参与骨髓间质干细胞的成骨向分化。在牙髓组织中,有TLR4表达的成牙本质细胞样细胞可向成牙本质细胞受损处迁移并形成修复性牙本质;而TLR2和TLR4作为参与牙髓防御反应的成员,在牙髓组织受损时,不仅可调节炎症因子的表达,还参与牙髓细胞成牙本质向分化的调控。由此可见,TLR2和TLR4在细胞成骨向分化中的作用机制值得进一步的探讨。     

Evidence for association between a Toll-like receptor 4 gene polymorphism and moderate/severe periodontitis in the Japanese population

BACKGROUND AND OBJECTIVE: Chronic periodontitis is an inflammatory disease caused by bacteria in subgingival pockets. Because Toll-like receptor 2 and Toll-like receptor 4 have been shown to play an important role in the recognition of periodontal pathogens, we investigated the relevance of genetic variations in TLR2 and TLR4 to susceptibility to periodontitis. MATERIAL AND METHODS: A total of 97 patients with chronic periodontitis and 100 control subjects were examined for mutations in TLR2 and TLR4. Case-control analysis was performed using individual single nucleotide polymorphisms detected during the mutation search. RESULTS: The missense mutations reported previously in TLR2 (677 Arg>Trp and 753 Arg>Gln) and in TLR4 (299 Asp>Gly and 399 Thr>Ile) were not detected in 97 of the Japanese patients with chronic periodontitis or in 100 of the Japanese control subjects. Nine single nucleotide polymorphisms were identified in exons of TLR2 and TLR4. The case-control analysis revealed that the frequency of the C/C genotype at base-pair position +3725 in TLR4 was significantly higher in both the moderate and the severe periodontitis patient group than in the control group. CONCLUSION: A genetic variation of TLR4 might be associated with moderate and severe periodontitis in the Japanese population.     

模式识别受体和病原体相关分子模式及其在牙周病防御中的作用

模式识别受体(PRR)是宿主抵抗病原微生物的感应器,可识别一种或多种病原体相关分子模式(PAMP),可及时向下游通路转导信号,引发先天性免疫反应.PAMP包括脂多糖(LPS)、脂磷壁酸、肽聚糖和甘露糖等.不同的PAMP可被不同的Toll样受体(TLR)识别或组合识别,然后通过一系列蛋白质级联反应激活细胞因子,从而有效地活化天然免疫系统.PAMP作用于TLR后,可促进炎性细胞因子的合成与释放;诱导一氧化氮依赖性杀菌活性和呼吸爆发;介导由细菌脂蛋白引起的人单核细胞系和表达TLR2的上皮细胞系程序性细胞死亡;LPS通过作用于TLR4促进树突细胞成熟,诱导TLR2的合成与表达,进而分泌白细胞介素-6等细胞因子.对TLR的研究将有助于认识慢性牙周病并为其治疗提供新的方法,故本文就牙龈上皮表面的PRR和牙周致病菌表面的PAMP及其在牙周病中的防御作用等研究进展作一综述.     

Neurokinin-1受体介导P物质对破骨细胞骨吸收功能的影响

目的 　了解P物质对体外培养大鼠破骨细胞骨吸收功能的影响和作用机制,探讨P物质在正畸牙槽骨改建中的调控机制。方法　 通过机械分离新生大鼠四肢长骨方法体外培养破骨细胞,细胞免疫组织化学染色观察NK1受体在大鼠破骨细胞内的表达情况;加入含不同浓度P物质（10-7-10-4 mol/L）和10-5 mol/L P物质受体拮抗剂（NK1受体拮抗剂）的培养液,观察P物质和NK1受体拮抗剂对破骨细胞骨吸收功能的影响。结果 免疫组化染色发现,大
鼠破骨细胞内NK1受体呈强阳性表达,着色位于细胞浆,胞核呈阴性;P物质明显增加破骨细胞的骨吸收陷窝面积（P<0.05）,但未见骨吸收陷窝数目明显增加（P>0.05）。NK1受体拮抗剂抑制了P物质对破骨细胞骨吸收功能的刺激
效应。结论 NK1受体可能介导P物质增强破骨细胞骨吸收功能,从而在正畸牙槽骨改建中发挥局部调节作用。     

IGF-1 and insulin receptor expression in the minor salivary gland tissues of Sjögren's syndrome and mucoceles--immunohistochemical study

OBJECTIVE: To investigate the expression of IGF‐1 receptors and insulin receptors on the minor salivary gland (MSG) tissues of patients diagnosed with Sjögren's syndrome (SS) and normal salivary gland tissue surrounding mucoceles. SUBJECTS AND METHODS: Five MSG tissue sections from SS and seven from mucocele patients were stained immunohistochemically using antibody to IGF‐1 receptor and insulin receptor in a horse radish peroxidase and DAB system. RESULTS: The expression of the insulin receptor was increased in the SS sections compared with controls, while the insulin‐like growth factor‐1 receptor was more intensely expressed in the controls. CONCLUSION: The presence of differential expression of receptors for IGF and insulin might suggest a possible role of these growth factors in the pathogenesis of SS.     

Nociceptin/orphanin FQ up‐regulates P2X3 receptors in primary cultures of neonatal rat trigeminal ganglion neurons

Recent evidence indicates a nociceptive role of the nociceptin/orphanin FQ–opioid receptor‐like receptor (N/OFQ‐ORL1) system in craniofacial pain; however, the mechanisms of such an effect remain unclear. We investigated whether the action of N/OFQ involves the modulation of P2X₃, a pain‐transducing ionotropic receptor. Double‐labeled immunohistochemical staining was used to determine the co‐localization of ORL1 and P2X₃ receptors in the trigeminal ganglia (TG) of neonatal Sprague‐Dawley rats. The effect of N/OFQ (at a concentration ranging from 1 pM to 10 nM) on the expression of P2X₃ receptors was detected by RT‐PCR, western blotting, and immunocytochemical staining. We found that ORL1 receptors were co‐localized with P2X₃ receptors and that the application of N/OFQ could up‐regulate, in a concentration‐dependent manner, the expression of P2X₃ receptor mRNA and P2X₃ receptor protein in TG neurons. Immunocytochemical staining also revealed enhanced P2X₃ immunoreactivity beneath the neuronal membrane and an increased percentage of P2X₃‐positive neurons after treatment with N/OFQ. Those effects were completely blocked by a specific ORL1 antagonist, UFP‐101. Our results suggest that the activation of ORL1 receptors by N/OFQ can potentiate P2X₃ receptors in primary cultures of neonatal trigeminal neurons, which may be a mechanism for the nociceptive role of N/OFQ in the modulation of craniofacial pain. Our findings may also have implications in treating craniofacial pain.     

Genetic polymorphism studies in periodontitis and Fcγ receptors

Periodontitis is a complex chronic subgingival plaque-induced inflammatory disease influenced by multiple factors, including genetics, behavior and the environment. Many genetic association studies have been conducted in periodontology. One of the most extensively investigated gene families is the Fcγ receptor gene family, which plays a key role in regulating host immune responses to bacteria. Unlike other genetic polymorphisms reported in periodontology, most Fcγ receptor polymorphisms reported not only have established biological functions but are reported to associate with other autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. There are, however, few recent reviews summarizing the association of this gene family with periodontitis. This article critically reviews the current understanding of genetic polymorphism studies in periodontitis, then summarizes the research status of Fcγ receptor polymorphisms and periodontitis and also of other genes involved in the regulatory network of Fcγ receptors, with special reference to their anticipated biological roles. Moreover, some possible future research directions in the related area are discussed.     

P2Y受体与三叉神经痛之间的关系

腺苷三磷酸(ATP)作为一种重要的神经递质具有广泛的生物学效应。多种伤害性刺激均可引起三叉神经节(TG)神经元释放ATP,ATP激活P2受体可引起疼痛。P2受体又分为P2X和P2Y两类。在受损的TG神经元上,P2Y受体的表达明显增多。本文就ATP与P2Y受体表达间的相关性、P2Y受体在TG中的信号转导机制、P2Y受体对神经损伤性痛觉信号的转导作用等研究进展作一综述。