Toll样受体4信号转导研究进展

Toll样受体4(TLR4)作为LPS信号转导受体,在与LPS反应时可形成一个由TLR4和MD 2构成的复合体,其在细胞内的信号转导依赖于不同的接头蛋白。在早期反应时,TLR4依赖MyD88和Mal可导致NF кB激活;而在后期反应中,通过TRIF和TRAM可引起NF кB和IRF3的迟发激活。由此诱导细胞因子、化学趋化因子和其他转录因子的表达。     

脂多糖对牙周膜干细胞生物学特性的影响

探讨脂多糖（LPS）对牙周膜干细胞（PDLSCs）生物学特性的影响.方法 分离、培养PDLSCs,并检测其间充质干细胞标志物STRO-1、CD146的表达情况.在含有LPS的培养基中培养PDLSCs,分别进行以下实验：（1）应用甲苯胺蓝染色法和Brdu掺入法分别检测PDLSCs的克隆形成率和细胞增殖率;（2）对PDLSCs进行骨向和脂肪向诱导,采用茜素红染色和油红O染色检测其骨向和脂肪向分化潜能;（3）应用ELISA法测定培养上清中IL-6的浓度;（4） Western blot检测PDLSCs磷酸化ERK1/2的表达情况.结果 PDLSCs表达STRO-1、CD146,阳性率分别为28.6％±2.3％、86.7％±3.9％.LPS对PDLSCs的克隆形成率和细胞增殖率没有影响.在含有LPS的矿化诱导液中,矿化面积明显增多,说明LPS能够促进PDLSCs骨向分化.脂肪向诱导实验发现,LPS组和无LPS组的油红染色阳性面积相近,两组无显著性差异.LPS促进IL-6的分泌和ERK1/2活化,并具有剂量依赖性.结论 LPS改变了PDLSCs的生物学特性,提示炎性状态可能影响PDLSCs介导的牙周组织再生.     

Toll样受体2和Toll样受体4在HBV感染后的免疫作用

Toll样受体（TLR）是启动固有免疫和调节适应性免疫的重要分子,参与肝脏对病毒及细菌的免疫TLR2、TLR4过程。在HBV的慢性化进程中,TLR2、TLR4与Thl和Th2的免疫平衡及调节性T细胞（Treg）的免疫抑制相关,HBV感染后,HBcAg刺激巨噬细胞产生TNF—α的作用需要TLR2参与,HBeAg的表达与否与TLR2的表达状态有关,而TLR4通过诱导iNOS的表达和激发HBV特异性免疫在体内抗HBV过程中起重要作用：     

Toll样受体4信号转导研究进展

Toll样受体（Toll-like-receptors,TLRs）是一个主要分布于炎症细胞的识别病源分子的受体超家族,其中TLR4主要识别革兰阴性细菌细胞壁成分脂多糖（lipopolysaccharide,LPS）。LPS与TLR4结合后活化髓样分化因子88 (myeloid differentiation factor 88, MyD88)依赖性和非依赖性两条信号途径;前者活化丝裂原激活的蛋白激酶（mitogen-activated protein kinase,MAPK）和核因子-κB（nuclear factor kappa B,NF-κB）信号通路,后者活化NF-κB和干扰素调节因子-3(IFN-regulated factor-3,IRF3)信号通路。通过这些信号途径TLR4诱导炎症细胞释放炎症因子介导炎症反应;同时TLR4通过活化树突状细胞促进抗原递呈,介导先天性免疫向获得性免疫的转化。此外,TLR4能诱导磷脂酰肌醇-3激酶-蛋白激酶B（PI3K-AKT）的信号转导,LPS介导的细胞存活和增殖与TLR4活化 PI3K-AKT途径有关。     

Toll样受体在免疫学方面的研究进展

天然免疫分子Ｔｏｌｌ样受体 (Ｔｏｌｌ ｌｉｋｅｒｅｃｅｐｔｏｒｓ,ＴＬＲ) ,是一个广泛存在于昆虫、脊椎动物和植物中序列高度保守而古老的家族。目前 ,已克隆的人类的ＴＬＲ成员有 10个 (即ＴＬＲ1～ 10 ) ,它们在天然免疫中可发挥重要的抗感染免疫功能 ,并与免疫耐受、特异性抗感染免疫 ,以及一些疾病具有相关性。本综述介绍了有关它们在配体的识别、信号传导、免疫学方面的研究进展。1　ＴＬＲ家族的成员、组织分布及结构特点1997年 ,第一个与果蝇Ｔｏｌｌ蛋白同源的人ＴＬＲ(ＴＬＲ4 )首次得到证实。迄今 ,在人类已发现 10种ＴＬＲ(…     

Toll样受体1对间充质干细胞免疫调节Th17细胞的作用

背景：课题组前期研究表明间充质干细胞具有免疫调节Th17细胞的作用,但内在的调节机制尚待阐明,为此,针对Toll样受体1在其中的作用进行探讨,为今后潜在的细胞治疗策略提供可能的实验依据。目的：探讨Toll样受体1对间充质干细胞免疫调节Th17细胞的作用。方法：贴壁法分离人胚胎骨髓来源间充质干细胞,免疫磁珠法分离正常人CD4⁺ T细胞。CD4⁺ T细胞单独培养或与间充质干细胞共培养4 d。实时定量聚合酶链反应测定白细胞介素17、Toll样受体1相关基因的表达水平;流式细胞仪检测Th17细胞的数量。结果与结论：CD4⁺ T细胞及间充质干细胞均表达Toll样受体1。相对于CD4⁺单独培养组,间充质干细胞共培养组(间充质干细胞+CD4)白细胞介素17明显升高(3.59±0.11,1.14±0.08,P < 0.01);进一步发现Toll样受体1 mRNA表达水平亦相应升高(6.07±1.79,1.53±0.63,P < 0.01)。流式细胞仪检测发现,共培养组(间充质干细胞+CD4)Th17细胞数量明显高于CD4⁺ T细胞组[(4.53±1.27)%,(2.39±0.80)%,P < 0.01)。研究结果表明Toll样受体1可能参与间充质干细胞免疫调节人Th17细胞的作用。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Toll样受体2和Toll样受体4在免疫应答衣原体感染中的作用

衣原体是重要的人类病原体,其能够导致多种疾病的发生.由衣原体引起的许多人类疾病被认为是免疫病理学介导的.已经证明Toll样受体(TLRs)是多种病原体感染的主要模式识别受体( PRRs),在起始固有免疫应答,建立适应性免疫应答中发挥着重要作用.在TLR家族中,TLR2和TLR4与衣原体感染的相关性研究备受关注,在识别衣原体感染、调节宿主的早期免疫应答、炎症反应和病理形成中执行着关键性的作用.研究TLR2和TLR4在免疫应答衣原体感染中的作用可以更好地理解TLRs介导的分子免疫机制,可能有助于研发免疫治疗的分子靶标,最终有效预防、控制衣原体感染引起的疾病.     

Toll样受体研究进展

Toll最早在果蝇中被发现。Toll受体蛋白 (d Toll)不仅参与果蝇胚胎发育时背腹的形成 ,而且参与成蝇对病原体侵袭的先天性免疫应答 ,是微生物诱导成年果蝇产生抗菌肽的信号转导通道的门户。 Toll样受体是先天性模式识别受体 ,在细胞活化信号的转导中起重要作用。它作为联系先天性与获得性免疫系统的桥梁 ,备受人们关注     

Toll样受体与造血

Toll样受体（TLR）是近年来发现的一类天然免疫受体,在天然免疫及获得性免疫过程中均发挥非常重要的作用。对TLR的深入研究表明,TLRs在造血相关细胞（造血干／祖细胞、间充质干细胞、血管内皮细胞等）上均有不同程度的表达,并且发挥一定生物学效应。     

Toll 样受体及其信号转导

天然免疫系统作为宿主第一道防线 ,主要在获得性免疫系统被活化前发挥抗感染作用 ,它依赖胚系基因编码的识别系统对病原微生物起反应。其主要作用方式是通过产生抗菌肽或蛋白以及吞噬作用直接破坏入侵的病原体 ,并判定病原体入侵部位和强度 ,调控获得性免疫反应。新近实验资料显示天然免疫识别微生物机制可能主要归功于Ｔｏｌｌ样受体 (Ｔｏｌｌ ｌｉｋｅｒｅｃｅｐｔｏｒ ,简称ＴＬＲ家族 )。本文对ＴＬＲ家族在机体防御机制中的作用和各种ＴＬＲ对微生物的识别及其信号转导机制的进展作一概述。1　ＴＬＲ家族Ｔｏｌｌ基因最初是在研究果蝇…     

牙周膜干细胞诱导骨髓间充质干细胞的牙向分化

目的 探讨牙周膜干细胞(PDLSC)诱导骨髓间充质干细胞(BMMSC)牙向分化的机制,为联合应用PDLSC和BMMSC再生牙周复合体提供实验依据.方法应用Transwell(R)小室法间接联合培养小型猪PDLSC和BMMSC,根据二者混合比例随机分为3组.A组:P∶M=10∶1共培养组;B组:P∶M=1∶1共培养;C组:P:M=1:10共培养,单独PDLSC和BMMSC培养组分别为阳性和阴性对照组.培养14 d,应用免疫荧光染色和实时定量PCR(qRT-PCR)分别检测scleraxis、osteocalcin(OCN)、osterix(OSX)、细胞外基质磷酸糖蛋白(MEPE)蛋白和mRNA表达情况,以判定PDLSC诱导BMMSC成牙的最佳配比比例.结果 免疫荧光染色和qRT-PCR结果均显示scleraxis、OCN和OSX相对mRNA表达水平在A、B、C组间没有统计学差异(P>0.05),但相对MEPE mRNA表达水平在A组却明显高于B组和C组(P＜0.01).结论 联合培养可促进BMMSC获得不同程度的PDLSC特性,且少量的PDLSC同样可以促进BMMSC获得牙源性干细胞特性.     

人牙周膜干细胞与牙周膜细胞生物学特性的比较

背景：牙周膜干细胞生物作用是目前牙周病治疗研究的热点,牙周膜成纤维细胞是其分化的终末功能细胞之一,也是其主要的支持细胞,两者生物学特性的差异研究鲜有报道。 目的：比较牙周膜干细胞与牙周膜细胞生物学特性的差异。 方法：用组织块法体外对牙周膜细胞以及单细胞克隆分离纯化后的人牙周膜干细胞两种细胞分别进行显微镜下形态观察,CCK8法检测并绘制2种细胞的生长曲线。流式细胞分析比较2种细胞的细胞周期以及细胞表面标记物的表达、实时PCR对2种细胞碱性磷酸酶、增殖细胞核抗原和Scleraxis基因进行检测。 结果与结论：牙周膜干细胞与牙周膜成纤维细胞外观差别明显,人牙周膜干细胞的生长曲线培养前5 d要低于牙周膜细胞,但在5 d后明显高于牙周膜细胞。人牙周膜干细胞与牙周膜细胞的细胞周期分别为41.1%和23.9%。表面标记物检测结果显示2种细胞虽有相似的表达,但在表达率差异有有显著性意义。实时荧光定量PCR结果显示,人牙周膜干细胞在碱性磷酸酶、增殖细胞核抗原以及Scleraxis基因的表达检测均高于牙周膜细胞。表明牙周膜干细胞在成骨增殖等生物学功能上比牙周膜细胞具有更强的潜能。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

地塞米松诱导牙周膜干细胞的定向成骨分化及凋亡

背景：牙周膜干细胞是一类起源于牙组织的成体干细胞,具有良好的成骨分化能力,有望在骨组织工程中得到应用。 目的：观察成骨诱导液对牙周膜干细胞成骨分化能力及细胞早期凋亡的影响。 方法：从原代牙周膜组织中分离得到牙周膜干细胞,以1×10⁴/cm²浓度铺板后开始诱导。利用1,10,100 nmol/L地塞米松、β-磷酸甘油钠、维生素C为成骨诱导剂,以碱性磷酸酶活性检测、茜素红矿化结节染色、荧光定量PCR等方法对细胞成骨情况进行鉴定,采用AnnexinV/PI双染法检测细胞凋亡情况。 结果与结论：地塞米松可有效诱导牙周膜干细胞成骨分化,可显著提高碱性磷酸酶活性,促进茜素红矿化结节形成,提高成骨相关基因骨粘连蛋白及Ⅰ型胶原表达。根据碱性磷酸酶活性和矿化结节实验结果,地塞米松的成骨诱导具有浓度梯度效应,其中100 nmol/L 地塞米松具有最佳成骨诱导能力。细胞凋亡结果提示,地塞米松诱导的成骨分化具有一定促凋亡作用,可诱导牙周膜细胞的早期凋亡。     

Up-regulated osteogenic transcription factors during early response of human periodontal ligament stem cells to cyclic tensile strain

Introduction

As one group of periodontal ligament (PDL) cells, human periodontal ligament stem cells (hPDLSCs) have been isolated and identified as mesenchymal adult stem cells (MSCs) since 2004. It has been well accepted that PDL sensitively mediates the transmission of stress stimuli to the alveolar bone for periodontal tissue remolding. Besides, the direction of MSCs differentiation has been verified regulated by mechanical signals. Therefore, we hypothesized that tensile strain might act on hPDLSCs differentiation, and the early response to mechanical stress should be investigated.

Material and methods

The hPDLSCs were cultured in vitro and isolated via a magnetic activated CD146 cell sorting system. After investigation of surface markers and other experiments for identification, hPDLSCs were subjected to cyclic tensile strain at 3,000 µstrain for 3 h, 6 h, 12 h, and 24 h, without addition of osteogenic supplements. In the control groups, the cells were cultured in similar conditions without mechanical stimulation. Then osteogenic related genes and proteins were analyzed by RT-PCR and western blot.

Results

Cyclic tensile strain at 3,000 µstrain of 6 h, 12 h, and 24 h durations significantly increased mRNA and protein expressions of Satb2, Runx2, and Osx, which were not affected in unloaded hPDLSCs.

Conclusions

We indicate that hPDLSCs might be sensitive to cyclic tensile strain. The significant increase of Runx2, Osx and Satb2 expressions may suggest an early response toward osteogenic orientation of hPDLSCs.     

In vitro neural/glial differentiation potential of periodontal ligament stem cells

Introduction

It is known that periodontal ligament stem cells (PDLSCs) can differentiate into cementoblast-like cells, adipocytes and collagen-forming cells. However, whether PDLSCs are able to differentiate into Schwann cells and which method is best for their neural induction remain unknown. We attempted to determine whether PDLSCs possessed the potential for neural differentiation in vitro.

Materials and methods

We isolated and multiplied PDLSCs from periodontal ligaments obtained from the teeth (n = 24) of 8-month-old beagle dogs. Four protocols with different chemicals and growth factors were adopted to induce the PDLSCs to differentiate into Schwann cells. Immunochemistry, RT-PCR and qRT-PCR were performed to investigate the in vitro neural differentiation potential of PDLSCs.

Results

We compared the 4 different protocols and showed that all 4 protocols could successfully induce PDLSCs to express nestin, GFAP and S100, markers for Schwann cells. Further, qRT-PCR revealed relative differences in the expression levels of these 3 genes in differentiated PDLSCs obtained by different protocols.

Conclusions

We conclude that PDLSCs have neural/glial differentiation potential in vitro and that neural/glial differentiation can be induced in PDLSCs if suitable protocols are followed. We also found that supplementing the growth medium with suitable growth factors is more effective than applying chemicals alone. While nerve growth factor is more effective than platelet-derived growth factor for inducing neural/glial differentiation in PDLSCs, pre-induction of PDLSCs with dimethyl sulphoxide yields better results than those obtained with all-trans-retinoic acid.     

Influence of different intensities of vibration on proliferation and differentiation of human periodontal ligament stem cells

Introduction

To understand the effects of low-magnitude, high-frequency (LMHF) mechanical vibration at different intensities on human periodontal ligament stem cell (hPDLSC) proliferation and osteogenic differentiation.

Material and methods

The effect of vibration on hPDLSC proliferation, osteogenic differentiation, tenogenic differentiation and cytoskeleton was assessed at the cellular, genetic and protein level.

Results

The PDLSC proliferation was decreased after different magnitudes of mechanical vibration; however, there were no obvious senescent cells in the experimental and the static control group. Expression of osteogenesis markers was increased. The expression of alkaline phosphatase (ALP) and osteocalcin (OCN) mRNA was up-regulated at 0.1 g, 0.3 g, 0.6 g and 0.9 g magnitude, with the peak at 0.3 g. The type I collagen (Col-I) level was increased after vibration exposure at 0.1 g, 0.3 g, and 0.6 g, peaking at 0.3 g. The expression levels of both mRNA and protein of Runx2 and osterix (OSX) significantly increased at a magnitude of 0.1 g to 0.9 g, reached a peak at 0.3 g and then decreased slowly. The scleraxis, tenogenic markers, and mRNA expression decreased at 0.05 g, 0.1 g, and 0.3 g, and significantly increased at 0.6 g and 0.9 g. Compared with the static group, the F-actin stress fibers of hPDLSCs became thicker and clearer following vibration.

Conclusions

The LMHF mechanical vibration promotes PDLSC osteogenic differentiation and implies the existence of a magnitude-dependent effect of vibration on determining PDLSC commitment to the osteoblast lineage. Changes in the cytoskeleton of hPDLSCs after vibration may be one of the mechanisms of the biological effects.     

人生长激素对人牙周膜干细胞增殖及成骨分化的影响

背景:生长激素已被证明对于非牙源性间充质干细胞的增殖和骨向分化有促进作用,但对于人牙周膜干细胞的生物学效应还不明确.目的:探讨人生长激素对人牙周膜干细胞增殖以及成骨分化的影响.方法:用含0(对照组),10,100,200μg/L人生长激素的α-MEM完全培养基干预第3代人牙周膜干细胞,分别在第1,3,5,7天采用CCK...     

肥大细胞Toll样受体4在人慢性牙周炎牙龈组织中的表达

 目的：观察人慢性牙周炎牙龈组织中肥大细胞Toll样受体4（Toll-like receptor 4, TLR4）的表达,并探讨其在牙周炎发病中的可能作用。方法: 将68例自愿接受本研究的牙周炎患者按照牙周炎的病变程度分成3组：轻度牙周炎组（23例）、重度牙周炎组（25例）和正常对照组（20例）。取牙龈组织标本,4%中性甲醛液固定48 h以上。制作牙龈组织的连续切片,HE染色,光学显微镜下观察各实验组牙龈组织的组织学改变;免疫组化法染色观察各实验组牙龈组织TLR4的表达;免疫荧光双染色法观察TLR4在肥大细胞中的表达。结果： (1)与正常对照组相比,各慢性牙周炎组牙龈组织中TLR4的表达及TLR4在肥大细胞中的表达均显著升高（P<005）;(2)重度牙周炎组牙龈组织中TLR4表达的数量及TLR4在肥大细胞中的表达明显高于轻度牙周炎组（P<005）。结论：TLR4在牙龈组织中的表达及在肥大细胞中的表达量随着牙周炎的炎症程度加重而增加,提示TLR4,特别是肥大细胞TLR4可能在慢性牙周炎的发病和疾病进程中起着重要的作用。     

Periostin promotes migration,proliferation, and differentiation of human periodontal ligament mesenchymal stem cells

Overview: Periostin (POSTN) is critical to bone and dental tissue morphogenesis, postnatal development, and maintenance; however, its roles in tissue repair and regeneration mediated by human periodontal ligament mesenchymal stem cells (PDLSCs) remain unclear. The present study was designed to evaluate the effects of POSTN on hPDLSCs in vitro. Materials and Methods: hPDLSCs were isolated and characterized by their expression of the cell surface markers CD44, CD90, CD105, CD34, and CD45. Next, 100 ng/mL recombinant human POSTN protein (rhPOSTN) was used to stimulate the hPDLSCs. Lentiviral POSTN shRNA was used to knockdown POSTN. The cell counting kit-8 (CCK8) and scratch assay were used to analyze cell proliferation and migration, respectively. Osteogenic differentiation was investigated using an alkaline phosphatase (ALP) activity assay, alizarin staining, and quantitative calcium analysis and related genes/protein expression assays. Results: Isolated hPDLSCs were positive for CD44, CD90, and CD105 and negative for CD34 and CD45. In addition, 100 ng/mL rhPOSTN significantly accelerated scratch closure, and POSTN-knockdown cells presented slower closure at 24 h and 48 h. Furthermore, the integrin inhibitor Cilengitide depressed the scratch closure that was enhanced by POSTN at 24 h. The CCK8 assay showed that 100 ng/mL rhPOSTN promoted hPDLSC proliferation. Moreover, 100 ng/mL rhPOSTN increased the expression of RUNX2, OSX, OPN, OCN, and VEGF and enhanced ALP activity and mineralization. POSTN silencing decreased the expression of RUNX2, OSX, OPN, OCN, and VEGF and inhibited ALP activity and mineralization. Conclusions: POSTN accelerated the migration, proliferation, and osteogenic differentiation of hPDLSCs.