基质细胞衍生因子1在人炎症牙髓组织中表达的实验研究

目的:研究基质细胞衍生因子1(Stromal cell-derived factor-1,SDF-1)及其受体CXCR4在人炎性牙髓组织中的表达,探讨SDF-1/CXCR4轴在牙髓炎症发生发展中的可能作用。方法:采用免疫组织化学染色的方法检测SDF-1和CXCR4阳性细胞在健康、炎症牙髓组织中的分布情况。以实时荧光定量RT-PCR方法检测SDF-1mRNA在健康和炎症牙髓中的表达。结果:炎性牙髓中SDF-1、CXCR4主要分布于炎性细胞、成牙本质细胞和微血管内皮细胞。而正常组牙髓少见SDF-1、CXCR4阳性细胞。炎性牙髓中SDF-1mRNA的表达较健康牙髓显著增强。结论:与正常牙髓相比,炎性牙髓组织中SDF-1、CXCR4阳性细胞明显增多。炎性牙髓中SDF-1表达水平明显上调。SDF-1/CXCR4轴可能参与了牙髓炎症损伤和修复过程。     

Expression and significance of stromal cell-derived factor-1alpha and its receptor CXCR4 in human dental pulp cells

OBJECTIVE: To investigate the expression of CXCR4 in cultured human dental pulp cells (HDPC) in vitro and the corresponding ligand SDF-1alpha level of HDPC supenatants stimulated by lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha), and to explore the role of SDF-1alpha on the proliferation and the migration of HDPC. METHODS: The expression of CXCR4 in HDPC was detected by immunocytochemistry technique and indirect immunofluorescence technique. The culture supernatants of HDPC were collected after HDPC had been simulated by LPS and TNF-alpha of different concentrations for 48h and then the SDF-1alpha level was assayed by quantitative sandwich ELISA. Meanwhile, the effects of recombinant human SDF-1alpha (rhSDF-1alpha) on the proliferation and the migration of HDPC at different concentrations were observed by MTT and Boyden Chamber Assay. RESULTS: CXCR4 was expressed in cytomembrane of HDPC and SDF-1alpha was secreted into their normal cell supernatants with a concentration of (4513.55 +/- 962.92) ng/L. The secretion of SDF-1alpha was both significantly decreased by stimulation with LPS and TNF-alpha (P < 0.05). In addition, rhSDF-1alpha stimulated the HDPC proliferation at the concentrations of 50, 100, 200 microg/L (P < 0.01) and increased the chemotactic migration of HDPC significantly after 9h's incubation with the concentrations of 50, 100 microg/L (P < 0.05). CONCLUSIONS: SDF-1alpha accelerated the proliferation and the migration of HDPC which expressed CXCR4. SDF-1-CXCR4 axis may play a role in repair of pulp injury.     

基质细胞衍生因子-1及其受体CXCR4在成体干细胞迁移中的作用

基质细胞衍生因子-1是一种重要的造血与非造血系干细胞形态发生因子和趋化因子。基质细胞衍生因子-1与其受体CXCR4结合,所介导的成体干细胞迁移归巢在多种组织器官损伤后的再生修复中发挥重要作用。基质细胞衍生因子-1及其受体CXCR4组成的功能轴在成体干细胞尤其是骨髓源干细胞迁移方面的研究进展,为研究牙髓干细胞迁移提供了新的方向。     

Caries-related bacteria and cytokines induce CXCL10 in dental pulp

Marked infiltration of inflammatory cells, such as activated T-cells, is observed in the progression of pulpitis; however, little is known about the mechanism of their recruitment into pulpal lesions. It has been recently demonstrated that CXC chemokine ligand 10 (CXCL10) chemoattracts CXC chemokine receptor 3 (CXCR3)-positive activated T-cells. We therefore examined whether CXCL10 is involved in the pathogenesis of pulpitis. CXCL10 mRNA expression levels in clinically inflamed dental pulp were higher than those in healthy dental pulp. Immunostaining results revealed that CXCL10 was detected in macrophages, endothelial cells, and fibroblasts in inflamed dental pulp, and that CXCR3 expression was observed mainly on T-cells. Moreover, cultured dental pulp fibroblasts produced CXCL10 after stimulation with live caries-related bacteria, peptidoglycans, and pro-inflammatory cytokines. In contrast, heat-killed bacteria did not induce CXCL10 secretion. These findings suggest that CXCL10-CXCR3 may play an important role in the pulpal immune response to caries-related bacterial invasion. Abbreviations: CXCL10, CXC chemokine ligand 10; CXCR3, CXC chemokine receptor 3; IFN, interferon; FBS, fetal bovine serum; LTA, lipoteichoic acid; PGN, peptidoglycan; IL, interleukin; TNF, tumor necrosis factor; PBS, phosphate-buffered saline; ELISA, enzyme-linked immunosorbent assay; CCL, C-C chemokine ligand; TLR, Toll-like receptor; NOD, nucleotide oligomerization domain; HDPF, human dental pulp fibroblasts.     

基质细胞衍生因子1α及其受体CXCR4在人牙髓细胞中的表达

目的 研究体外培养人牙髓细胞(human dental pulp cells,HDPC)上CXCR4的表达情况,检测大肠杆菌脂多糖(lipopolysaccharide,LPS)和肿瘤坏死因子α(TNF-α)刺激后HDPC培养上清液中基质细胞衍生因子1α(stromal cell-derived factor-1α,SDF-1α)的表达水平,探讨人工重组SDF-1α(recombinant human SDF-1α,rhSDF-1α)对HDPC增殖及迁移的影响.方法 采用免疫细胞化学及间接免疫荧光技术检测HDPC上CXCR4的表达.用不同浓度LPS(0.1、1、10、100 mg/L)和TNF-α(1、10、100μg/L)刺激HDPC 48 h后,ELISA法检测HDPC培养上清液中SDF-1α含量的变化.同时甲基噻唑基四唑(MTT)法及体外趋化实验观察不同浓度rhSDF-1α对HDPC增殖及迁移的影响.结果 正常HDPC胞膜表达CXCR4且其培养上清液分泌SDF-1α,浓度约为(4513.55±962.92)ng/L.在用LPS和TNF-α刺激HDPC后,SDF-1α的表达水平均显著降低(P＜0.05).50、100和200μg/L的rhSDF-1α可促进HDPC的增殖(P＜0.05),50和100μg/L rhSDF-1α作用9 h可显著趋化HDPC的迁移(P＜0.01).结论 CXCR4在HDPC上表达且SDF-1α能促进HDPC的增殖及迁移;SDF-1-CXCR4轴可能在牙髓组织损伤修复中发挥重要作用.     

LPS promotes pre-osteoclast activity by up-regulating CXCR4 via TLR-4

Lipopolysaccharide (LPS) has been shown to be a prominent pathogenic factor in inflammatory bone loss. However, knowledge of the mechanisms involved is limited. The role of the SDF-1/CXCR4 (Stromal-derived factor-1 and its unique chemokine receptor) axis in LPS-induced bone loss has not been studied. The aim of this study was to investigate the role of the SDF-1/CXCR4 axis in LPS-stimulated inflammatory bone loss. The results show that LPS does not influence the expression of SDF-1/CXCR4 in osteoblasts, but up-regulates the expression of CXCR4 in pre-osteoclasts via Toll-like receptor 4, which subsequently enhances pre-osteoclast migration. Moreover, LPS promoted RANKL-induced osteoclast differentiation partially through CXCR4 up-regulation. In conclusion, the present study demonstrated, for the first time, that the up-regulated expression of CXCR4 in pre-osteoclasts by LPS stimulation is involved in LPS-induced bone resorption.     

Recruitment of exogenous mesenchymal stem cells in mandibular distraction osteogenesis by the stromal cell-derived factor-1/chemokine receptor-4 pathway in rats

Distraction osteogenesis is widely used in orthopaedic and craniofacial surgery. However, its exact mechanism is still poorly understood. The purpose of this study was to find out whether there is systemic recruitment of mesenchymal stem cells (MSC) to the neocallus in the distraction gap by the stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis during osteogenesis. We examined the migration of MSC towards a gradient of SDF-1 in vitro. We also transplanted MSC labelled with green fluorescent protein (GFP) intravenously, with or without treatment with CXCR4-blocking antibody, into rats that had had unilateral mandibular distraction osteogenesis, and investigated the distribution of cells labelled with GFP in the soft callus after 24 h. We found that SDF-1 facilitated the migration potency of MSC both in vitro and in vivo, and this migration could be inhibited by AMD3100, an antagonist of CXCR4, and promoted by local infusion of exogenous SDF-1 into the distraction gap. This study provides a new insight into the molecular basis of how new bone is regenerated during distraction osteogenesis.     

Expression of macrophage inflammatory protein 3alpha in human inflamed dental pulp tissue

Severe pulpitis resulting from dental caries is characterized by marked inflammatory infiltrate such as lymphocytes. Little is known about the recruitment of these cells into the dental pulp lesions of carious teeth. Macrophage inflammatory protein-3alpha (MIP-3alpha), a CC chemokine attracts CC chemokine receptor 6 (CCR6)-expressing T cells. We examined the distribution of MIP-3alpha-positive and/or CCR6-positive cells in human inflamed and normal dental pulp by immunohistochemistry. MIP-3alpha was observed in all inflamed pulp sections, and was mostly distributed in macrophages that had accumulated in the area adjacent to carious lesions. Furthermore, CCR6 expression was also observed in the infiltrating lymphocytes. In contrast, MIP-3alpha and CCR6 were rarely detected in normal pulp. These findings suggest that MIP-3alpha plays a role in the advancement of pulpal inflammation via the recruitment of CCR6-expressing lymphocytes.     

CXCR4受体在口腔鳞癌细胞系中的表达及对细胞增殖和迁徙的影响

目的:观察口腔鳞癌细胞系(OSCC)中趋化因子受体CXCR4的表达,检测SDF-1/CXCR4反应轴对OSCC增殖的作用,SDF-1对CXCR4阳性肿瘤细胞的趋化作用,探讨CXCR4受体在OSCC中的功能及活性。方法:细胞涂片免疫荧光法检测CXCR4蛋白在OSCC细胞系的表达,流式细胞仪直接免疫荧光法检测OSCC细胞系中CXCR4蛋白的表达量,MTT法检测细胞的增殖能力,体外迁徙实验检测SDF-1/CXCR4反应轴对OSCC细胞的趋化作用。采用SPSS10.0软件包进行ANOVA方差分析和t检验。结果:CXCR4蛋白在OSCC细胞系呈阳性表达,表达率为68.62%。OSCC细胞在SDF-l作用下,其增殖反应显著增强,CXCR4抗体可显著抑制肿瘤细胞的增殖,SDF-1可显著诱导OSCC细胞的移动。结论:CXCR4受体与OSCC细胞增殖、迁徙功能有一定关系。     

碱性成纤维细胞因子在人牙髓损伤修复过程中的表达

目的研究不同状态人牙髓组织中碱性成纤维细胞因子（b FGF）的表达特点,以及大肠杆菌脂多糖（LPS）刺激后人牙髓细胞（h DPC）中b FGF的表达水平,探讨b FGF在牙髓损伤修复过程中的可能作用。方法采用实时荧光定量聚合酶链反应（PCR）和免疫蛋白印迹方法（Western blot）分别检测正常、深龋及牙髓炎牙髓组织中b FGF m RNA和蛋白表达情况。实时荧光定量PCR测定1 mg/L LPS刺激h DPC 6、12、24、48 h后b FGF和热休克蛋白70（HSP70）表达水平的变化;Western blot和细胞免疫荧光染色检测LPS刺激h DPC后b FGF蛋白表达变化。结果实时荧光定量PCR和Western blot结果表明,深龋牙髓组织中b FGF水平显著上调,而正常和牙髓炎牙髓组织中b FGF表达无差异。实时荧光定量PCR检测到LPS刺激h DPC后,b FGF和HSP70 m RNA水平同步上调,在12 h达峰值;Western blot显示,LPS刺激h DPCs 12、24、48 h后b FGF蛋白表达水平均高于正常h DPC;细胞免疫荧光染色证实,LPS刺激12 h后h DPC中b FGF呈强阳性表达,而正常h DPC中b FGF呈弱阳性表达。结论 b FGF在深龋牙髓组织中高表达,且LPS刺激早期可上调h DPC内b FGF表达,推测b FGF可能参与牙髓组织防御修复反应,可能是细胞抗损伤的重要调节机制之一。     

人牙龈干细胞的分离鉴定及基质细胞衍生因子-1对其趋化效应的研究

目的 研究基质细胞衍生因子-1（SDF-1）受体CXCR4在人牙龈干细胞（GMSCs）上的表达及SDF-1对人GMSCs的趋化效应。方法 通过有限稀释法分离并培养人GMSCs,检测其表面干细胞标志物的表达情况,测试其克隆形成率及多向分化能力,利用免疫荧光染色法检测人GMSCs上SDF-1受体CXCR4的表达,用Transwell细胞培养室检测不同质量浓度SDF-1对人GMSCs的趋化反应,光镜下计数迁移至滤膜下侧面的不同视野的细胞数。结果 人GMSCs具有较高的自我更新能力,在体外呈克隆状生长,表达间充质干细胞表面标志物CD44、CD73、CD90、CD105和CD166,而造血干细胞表面标志物CD14、CD34和CD45的表达为阴性。体外诱导培养的人GMSCs能够向成骨细胞及成脂细胞分化,其克隆形成率为21.4%±2.8%。免疫荧光染色显示,人GMSCs表达SDF-1受体CXCR4。SDF-1的质量浓度为100、200 ng·mL^-1时,Transwell细胞培养室中迁移的细胞数目（每高倍视野分别为189.3±4.4和164.6±4.9）显著多于空白对照组（每高倍视野47.8±2.5）（P<0.01）;使用CXCR4中和抗体处理后,人GMSCs的迁移效应明显受到抑制（每高倍视野降低为29.0±2.4,P<0.01）。结论 人GMSCs表达趋化因子SDF-1受体CXCR4,SDF-1对人GMSCs有趋化效应,这种趋化效应可能是通过其特异性受体CXCR4介导的。     

基质细胞衍生因子-1刺激对周期性牵张力作用下ATDC5细胞的趋化因子受体4、白介素-6、胶原X表达的影响

目的 探讨诱导后ATDC5软骨细胞在20%形变的周期性牵张力及基质细胞衍生因子-1（SDF-1）刺激下,趋化因子受体4（CXCR4）、白介素（IL）-6及胶原X的表达变化,以期深入研究SDF-1/CXCR4信号轴在软骨细胞分化中的作用机制。方法 ATDC5细胞系经胰岛素铁硒传递蛋白（ITS）诱导3周后,分为加力和不加力两大组,每大组又分为对照组和SDF-1组。对加力组施以20%形变的拉伸力12 h。加力结束后,对各组细胞提取总蛋白,对CXCR4、IL-6及胶原X的蛋白表达进行Western blot检测。结果在不加力状态下,给予SDF-1刺激后,软骨细胞CXCR4、IL-6及胶原X的表达都出现了不同程度的增强;而在20%形变力和SDF-1的双重刺激下,此3种因子的表达出现进一步增强。结论 在异常应力作用下,SDF-1可通过上调其特异性受体CXCR4的表达进而增大与其结合的效率,最终促使SDF-1/CXCR4信号轴的激活,促进IL-6等炎症因子的表达增强,以及直接促进软骨细胞的肥大向分化,进而胶原X的表达量增高。     

基质细胞趋化因子-1对人牙周膜干细胞趋化因子受体——CXC亚家族受体4表达的影响研究

目的:证实人牙周膜干细胞(human periodontal ligament stem cells,hPDLSCs)表达趋化因子受体——CXC亚家族受体4(cysteine X cysteine receptor 4,CXCR4)及探究趋化因子基质细胞趋化因子-1(stromalcell-derived factor1,SDF-1)和阻断剂AMD3100(商品名:普乐沙福)对CXCR4表达的影响,从而为探究牙周膜干细胞生物学效应的影响提供理论基础。方法:采用消化组织块法联合有限稀释法分离纯化得到hPDLSCs,取第3代hPDLSCs随机分为3组:阴性对照组、SDF-1组(200μg/L SDF-1),SDF-1+AMD3100组(200μg/L SDF-1+10 mg/L AMD3100)。利用Western blot检测CXCR4在hPDLSCs上的表达及在SDF-1、AMD3100作用下CXCR4表达的变化。结果:1.筛选后的hPDLSCs可被诱导分化为成骨细胞和成脂细胞,证实其具有多向分化潜能;利用流式细胞仪检测其细胞表型鉴定其符合牙周膜干细胞的免疫表型。2.Western blot检测结果显示hPDLSCs上表达CXCR4,且应用SDF-1后上调CXCR4的表达,SDF-1+AMD3100组无明显变化。结论:1.hPDLSCs可从新鲜离体牙的牙周膜中培养获得,经有限稀释法纯化后鉴定为间充质来源。2.hPDLSCs上表达CXCR4,SDF-1通过上调hPDLSCs上CXCR4的表达,AMD3100可阻断SDF-1与其受体CXCR4结合。     

Leptin Receptor Is Up-regulated in Inflamed Human Dental Pulp

Introduction

After leptin receptor (LEPR) identification in hematopoietic, immune system, and other tissues, a role for leptin regulating inflammation and immune response has been accepted. This study aims to describe the possible expression of LEPR in healthy human dental pulp and to compare it with LEPR expression in inflamed human dental pulp.

Methods

Twenty-one pulp samples were obtained from freshly extracted caries-free and restoration-free human third molars. In 7 third molars (inflamed pulp group), inflammation was experimentally induced before extraction. Pulp samples were processed, and LEPR expression was determined by quantitative real-time polymerase chain reaction, and the amount of LEPR protein was analyzed by immunoblot.

Results

All healthy and inflamed dental pulp samples expressed LEPR. Western blot analysis of human dental pulp revealed the presence of a protein with an apparent molecular weight of approximately 120 kDa, which corresponds to the estimated molecular weight of LEPR. The expression of LEPR mRNA was confirmed by quantitative real-time polymerase chain reaction analysis, and the size of the amplified fragment (338 base pairs for LEPR and 194 base pairs for cyclophilin) was assessed by agarose gel electrophoresis. The relative amount of LEPR in inflamed pulps was approximately 50% higher than in healthy pulps (P < .05).

Conclusions

The presence of LEPR in human dental pulp tissues has been demonstrated for the first time. The up-regulation of LEPR expression in inflamed pulp samples suggests that leptin can play a role in inflammatory and local immune responses in human dental pulp.     

rhPDGF-BB对糖尿病大鼠骨髓基质干细胞迁移的促进作用

目的: 体外评价不同浓度人重组血小板衍生生长因子BB（recombinant human platelet derived growth factor-BB, rhPDGF-BB）对糖尿病大鼠骨髓基质干细胞（BMSCs）迁移的影响,以及基质细胞衍生因子（stromal cell-derived factor 1,SDF-1）和其G 蛋白偶联受体CXCR4调控作用的相关机制,为rhPDGF-BB应用于临床糖尿病患者相关骨修复再生治疗提供理论基础。方法: 建立链脲佐菌素诱导的糖尿病大鼠动物模型。体外培养糖尿病大鼠BMSCs,作为对照组。采用Transwell小室趋化模型,以浓度0、10、50、100 ng/mL rhPDGF-BB作用BMSCs,检测其体外趋化作用;定时定量RCR检测BMSCs SDF-1、CXCR4 mRNA的表达变化,筛选出药物最佳作用浓度;应用PI3K/Akt抑制剂,反向证实rhPDGF-BB对BMSCs的SDF-1、CXCR4表达的调节作用。采用SPSS 17.0软件包对数据进行统计学分析。结果: 链脲佐菌素诱导的糖尿病大鼠,1周后选取大鼠尾静脉血糖浓度高于16.7 mmol/L者为建模成功大鼠。与糖尿病大鼠的BMSCs相比,rhPDGF-BB促进糖尿病大鼠BMSCs的迁移,50 ng/mL rhPDGF-BB为促进糖尿病大鼠BMSCs迁移的最佳作用浓度,PI3K/Akt抑制剂明显抑制糖尿病大鼠BMSCs的迁移。结论: rhPDGF-BB促进糖尿病大鼠BMSCs的迁移,并通过SDF-1/CXCR4轴,调节糖尿病大鼠BMSCs的迁移。     

脂多糖信号受体CD14、TLR4在人牙髓组织和牙髓成纤维细胞中的表达

目的研究人牙髓组织和牙髓成纤维细胞中脂多糖（LPS）信号受体CD14、TLR4的表达特点,探讨牙髓炎症组织中LPS的信号转导途径.方法采用免疫组化染色法观察健康和炎症牙髓组织中CD14、TLR4的表达情况;应用直接免疫荧光标记法,采用流式细胞术检测体外培养人牙髓成纤维细胞在LPS刺激前后的CD14、TLR4阳性细胞率和细胞表面平均荧光强度.结果正常牙髓组织中未见CD14、TLR4阳性细胞;炎症牙髓组织中可见大量CD14、TLR4阳性细胞,CD14、TLR4阳性细胞率差异无统计学意义（P＞0.05）.牙髓成纤维细胞经LPS刺激后,TLR4平均荧光表达强度和TLR4阳性细胞率均显著增高（P＜0.05）,而CD14在LPS刺激前、后均无表达.结论炎症牙髓组织中CD14、TLR4的阳性表达,提示LPS可能通过CD14、TLR4信号受体在牙髓炎症组织中发挥作用,而牙髓成纤维细胞在LPS刺激后仅表达TLR4,表明LPS可能通过TLR4对牙髓成纤维细胞发挥作用.