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。     

Toll-like receptor 2 (TLR2) and TLR4 differentially activate human mast cells

In the present report we have analyzed whether human normal cord blood-derived mast cells (CBMC) could interact with bacterial products, especially lipopolysaccharide (LPS) from Escherichia coli and peptidoglycan (PGN) from Staphylococcus aureus, known as Toll-like receptor (TLR) 4 and TLR2 agonists, respectively. We found that both LPS and PGN induced significant release of not only tumor necrosis factor-alpha (TNF-alpha), but also IL-5, IL-10 and IL-13 by human mast cells (MC). We also established that the stimulation of CBMC with LPS or with PGN is mediated through interactions with TLR4 or with TLR2, respectively. Thus, our data indicate that activation of either TLR2 or TLR4 pathway may lead to a pro-Th2 immune response. However, the release of TNF-alpha induced by LPS, conversely to PGN, required the priming of CBMC by IL-4 and the presence of serum components, in particular soluble CD14. Of interest, stimulation by PGN, but not by LPS, induced release of histamine by human MC. Altogether, these findings provide the first evidence that human MC differentially respond towards bacterial components, and that their responses depend on TLR pathways and reveal human specificities in the pattern of cytokine production.     

Caspase-dependent and -independent apoptosis of mast cells induced by withdrawal of IL-3 is prevented by Toll-like receptor 4-mediated lipopolysaccharide stimulation

IL-3-dependent mucosal-like mast cells undergo apoptosis upon withdrawal of IL-3. Generally, the apoptosis is mediated by the activation of caspases and inhibited by addition of the pan-caspase inhibitors z-VAD-FMK or BOC-D-FMK. However, DNA fragmentation, a typical characteristic of apoptosis, is not inhibited by z-VAD-FMK or BOC-D-FMK in mast cell apoptosis. In this study, we demonstrate that the apoptosis of mast cells is mediated by both caspase-dependent and -independent mechanisms. The caspase-independent apoptosis is mediated by the translocation of endonuclease G from mitochondria into nuclei. Withdrawal of IL-3 caused down-regulation of Bcl-xL, resulting in a drop in mitochondrial membrane transition potential followed by the release of cytochrome c and endonuclease G from mitochondria. However, stimulation of mast cells through Toll-like receptor 4 (TLR4) by lipopolysaccharide prevented mast cell apoptosis by inducing expression of Bcl-xL. Moreover, the activation of mast cells by LPS is enhanced in the presence of IFN-gamma, which up-regulates the expression of cell surface TLR4. Taken together, these observations provide evidence that mast cells play important roles not only in allergic reactions but also in innate immunity recognizing enterobacteria through TLR4, and are regulated differently from allergic inflammation by Th1 cytokines.     

High-affinity IgE receptor-beta chain expression in human mast cells

The high-affinity IgE receptor (FcepsilonRI)-beta gene is one of the atopy-associated genes, but its biological significance is largely unknown. In this study, we generated the anti-FcepsilonRI-beta chain antibody to clarify beta-chain protein expression in human mast cells. The FcepsilonRI-beta antibody showed specific binding to a 27 kDa protein with Western blotting and membrane bound immunostaining using cultured mast cells. Monomeric IgE sensitization increased beta-chain expression as well as mature alpha-chain expression in mast cells. Upregulation of beta-chain expression with monomeric IgE treatment suggests possible roles of FcepsilonRI-beta protein as an atopy-related molecule.     

Intracellular localisation of Mycobacterium marinum in mast cells

AIM: To study the bacteriocidal or bacteriostatic role of mast cells during infection with Mycobacterium. METHODS: Mycobacterium marinum (M. marinum) (BAA-535/M strain) was investigated for its ability to grow at a temperature relevant to the mammalian host. Primary mast cells were differentiated from bone marrows of mice, a human mast cell line (HMC-1) and a human monocytic cell line (MonoMac6) were maintained in culture. Mice were stimulated by intraperitoneal injection of heat-killed M. marinum to study cytochemically the degranulation of peritoneal mast cells. HMC-1 cells were stimulated with M. marinum to analyse mRNA expression for inflammatory reactant genes, while HMC-1 and primary mouse mast cells were infected with M. marinum to establish in parallel cell viability (lactate dehydrogenase release and cell counts) and viable mycobacterial counts. Flow cytometry was used to assess intracellular presence of fluorescein isothiocyanate labelled M. marinum after trypan blue quenching and to measure the extent of infection-induced apoptosis or necrosis in HMC-1. A GFP expressing recombinant M. marinum strain was used to assess intracellular location by fluorescence microscopy. Light microscopy of osmium tetroxide and Gram Twort stained sections of 0.5 μm and transmission electron microscopy were undertaken as sensitive methods. RESULTS: Since its isolation, M. marinum has adapted to grow at 37 °C. This study found that M. marinum infects HMC-1 cells and primary murine mast cells, where they survive, replicate, and cause dose dependent cell damage over the analysis period of up to 120 h. Amikacin was an effective aminoglycoside antibiotic to eliminate extracellular or membrane attached M. marinum in order to adequately quantify the intracellular bacterial loads. In vivo, intraperitoneal injection of heat-killed M. marinum led to the release of mast cell granules in mice. HMC-1 cells stimulated with M. marinum showed a biphasic pattern of increased mRNA expression for LL-37 and COX-2/TNF-α during 24 h of stimulation. In HMC-1, M. marinum localised to the cytoplasm whereas in primary mast cells, M. marinum were found in vacuoles. CONCLUSION: The effector role of mast cells in infection with M. marinum can be studied in vitro and in vivo.     

Lipoteichoic acid downregulates FcepsilonRI expression on human mast cells through Toll-like receptor 2

BACKGROUND: FcepsilonRI on the surface of mast cells (MCs) plays a central role in allergic responses. Recent evidence shows that exposure to microbial components corresponds with a significant reduction in the risk for allergic diseases. Although many reports suggest that this is due to changes in T-cell functions, how MC functions are altered by bacterial infection remains unknown. OBJECTIVE: We sought to elucidate the effect of bacterial infection on MC function and expression of Fc receptors, such as FcepsilonRI. METHODS: Isolated human pulmonary MCs and a human MC line (LAD2) were stimulated with bacterial components, and the function and surface expression of Fc receptors were measured. RESULTS: Lipoteichoic acid (LTA) and peptidoglycan, but not LPS, flagellin, or 3CpG-oligodeoxynucleotide, reduced the expression of FcepsilonRI on LAD2 cells. An antibody to Toll-like receptor (TLR) 2 partially blocked the effect of LTA but not peptidoglycan. Both LTA and peptidoglycan reduced MC degranulation caused by an antigen-specific IgE. Furthermore, exposure of pulmonary MCs to LTA reduced both FcepsilonRI expression and IgE-induced degranulation. None of the bacterial components affected the expression of other Fc receptors, such as Fcgamma receptors or Fcalpha receptor I. CONCLUSIONS: Our results indicate that LTA reduces the surface expression of FcepsilonRI through TLR2 and suggests that TLR2 ligands could be used as a novel therapy for controlling allergic disorders. CLINICAL IMPLICATIONS: By knowing how bacterial components modulate MC function, we can expand our possibilities for therapeutic interventions of allergic diseases.     

类糜蛋白酶抑制剂对人大肠肥大细胞类胰蛋白酶释放的影响

目的：研究类糜蛋白酶抑制剂对人大肠肥大细胞释放类胰蛋白酶的影响。方法：人大肠组织经酶消化后，细胞成份有全HBSS重新悬浮。激发过程在LP4试管中、37℃条件下完成。类胰蛋白酶水平用酶联免疫吸附试验（ELISA）方法测定。结果：促分泌剂抗IgE抗体和CI在培养15分钟和35分钟时可明显刺激人大肠肥大细胞类胰蛋白酶的释放，在相同实验体系中，类糜蛋白酶抑制剂ZIGPFM、TPCK和α1-抗胰蛋白酶无明显刺激人大肠肥大细胞释放类胰蛋白酶的作用。类糜蛋白酶抑制剂均可以剂量依赖性的方式抑制抗IgE抗体诱导的类胰蛋白酶的释放，最大浓度的ZIGPFM（1 μmol／ml）、TPCK（80 μmol／ml）和α1-抗胰蛋白酶（30 μmol／ml）可分别抑制37％、40％和36．6％的类胰蛋白酶释放。在37℃条件下同大肠细胞预培养20分钟与无预培养相比，ZIGPFM和TPCK对抗IgE抗体诱导的类胰蛋白酶释放的抑制作用略增强。Amastatin对抗IgE抗体诱导的类胰蛋白酶的释放无作用。类糜蛋白酶抑制剂均可以剂量依赖性的方式抑制CI诱导的类胰蛋白酶的释放，抑制范围在23％-35．3％。在37℃条件下同大肠细胞预培养20分钟与无预培养相比，ZIGPFM对CI诱导的类胰蛋白酶释放的抑制作用有增强，TPCK则无此特点。结论：类糜蛋白酶抑制剂可抑制人大肠肥大细胞IgE依赖性和非依赖性类胰蛋白酶的释放，提示类糜蛋白酶抑制剂可望成为炎症性肠病或其它肥大细胞相关疾病的一个新的治疗途径。     

亮肽素、TLCK和乳铁蛋白对人结肠肥大细胞类胰蛋白酶释放的影响

目的：探讨亮肽素、N-甲苯磺酰-L-赖氨酸氯甲基化酮（TLCK）和乳铁蛋白对人结肠肥大细胞释放类胰蛋白酶的影响。 方法： 人结肠组织经酶消化后，细胞成份用全HBSS重新悬浮。激发过程在LP4试管中、37 ℃ 条件下完成。类胰蛋白酶水平用酶联免疫吸附试验（ELISA）方法测定。 结果： 亮肽素、TLCK和乳铁蛋白无明显刺激人结肠肥大细胞释放类胰蛋白酶的作用。但可以剂量依赖性的方式抑制抗IgE抗体诱导的类胰蛋白酶释放，抑制范围在36.6%-47.6%。在37 ℃条件下同结肠细胞预培养20 min与无预培养相比，亮肽素和TLCK对抗IgE抗体诱导的类胰蛋白酶释放的抑制作用无明显改变。亮肽素、TLCK和乳铁蛋白均可以抑制CI诱导的类胰蛋白酶释放，抑制范围在27.1%-44.1%。在37 ℃条件下同结肠细胞预培养20 min与无预培养相比，亮肽素对CI诱导的类胰蛋白酶释放的抑制作用明显增强，TLCK则无此特点。 结论： 我们首次发现类胰蛋白酶抑制剂可抑制人结肠肥大细胞IgE依赖性和非依赖性类胰蛋白酶释放，提示类胰蛋白酶抑制剂可治疗炎症性肠病或其它肥大细胞相关疾病。     

TLR2和TLR4在人慢性根尖周病组织肥大细胞上的表达

 目的: 观察人不同类型慢性根尖周病组织中肥大细胞(mast cells,MCs)上Toll样受体2(Toll-like receptor 2,TLR2)和TLR4的表达情况,探讨TLR2-类胰蛋白酶(tryptase)和TLR4-tryptase双阳性MCs在慢性根尖周疾病发病机制中的作用。方法: 将60例自愿参与本研究的受试者按根尖周病分类标准分为3组:(1)正常对照组;(2)根尖周肉芽肿组;(3)根尖周囊肿组。将根尖周组织标本置于4%甲醛固定液中浸泡48 h以上,制作连续组织切片。HE染色,光学显微镜下观察各组根尖周标本的组织学变化;免疫荧光双染色后于荧光显微镜下观察TLR2-tryptase和TLR4-tryptase双阳性MCs在根尖周组织中的分布情况。结果: 根尖周病变组TLR2-tryptase和TLR4-tryptase双阳性MCs比正常牙周膜组明显增多(P<0.01);与根尖肉芽肿组相比,根尖囊肿组TLR2-tryptase及TLR4-tryptase双阳性MCs数目明显增高(P<0.01)。结论: TLR2及TLR4在慢性根尖周疾病组织中MCs上表达增加,提示TLR2-tryptase及TLR4-tryptase双阳性MCs可能参与慢性根尖周病发病过程的免疫调节。     

Post-translational suppression of the high affinity IgE receptor expression on mast cells by an intestinal bacterium

Mast cells, which express the high-affinity IgE receptor (FcεRI) on their surface, play a crucial role in inducing allergic inflammation. Since mast cells are activated by crosslinking of FcεRI with IgE and allergens, the cell surface expression level of FcεRI is an important factor in determining the sensitivity to allergens. Recently, the involvement of gut microbiota in the prevalence and regulation of allergy has attracted attention but the precise underlying mechanisms are not fully understood. In this study, the effect of intestinal bacteria on cell surface expression of FcεRI was examined. Bacteroides acidifaciens type A 43 specifically suppressed cell surface expression of FcεRI on mouse bone marrow-derived mast cells (BMMCs) without reduction in FcεRI α and β-chain mRNA and total protein expression. The suppressive effect required sustained exposure to this bacterium, with a corresponding reduction in Erk activation. Inhibition of Erk decreased cell surface distribution of FcεRI in BMMCs, at least in part, through facilitated endocytosis of FcεRI. These results indicate that B. acidifaciens type A 43 suppresses cell surface expression of FcεRI on mast cells in a post-translational manner via inhibition of Erk. The suppression of FcεRI expression on mast cells by specific bacteria might be the underlying mechanism involved in the regulation of allergy by gut microbiota.     

肥大细胞在支气管哮喘中的研究进展

支气管哮喘(哮喘)是呼吸系统的常见病和多发病,肥大细胞是其主要的反应细胞,目前关于肥大细胞在哮喘中作用的研究取得了新的进展,特别是肥大细胞蛋白酶及其抑制剂的深入研究和哮喘患者气道平滑肌束中肥大细胞数量明显增加并呈脱颗粒状态的发现,引起学者们极大的关注,本文将就肥大细胞在哮喘中的研究进展进行综述。     

Toll-like receptor agonists differentially regulate cysteinyl-leukotriene receptor 1 expression and function in human dendritic cells

BACKGROUND: Dendritic cells (DCs) acquire, during their maturation, the expression of the chemokine receptor CCR7 and the ability to migrate to lymph nodes in response to CC chemokine ligand 19 (CCL19). This migration is impaired in mice lacking the leukotriene (LT) C4 transporter and restored by addition of exogenous LTC4. OBJECTIVE: To define the role of LT in human DC function, we studied the expression and function of the cysteinyl-leukotriene (CysLT) receptors during DC differentiation from monocytes and subsequent maturation. METHODS: Receptor expression was measured by flow cytometry and real-time PCR. Responsiveness to LTD4 stimulation was assessed by calcium flux and chemotaxis. RESULTS: Maturation of DC with LPS, a classic Toll-like receptor 4 agonist, reduced CysLT receptor 1 (CysLT1) expression by 50%, whereas CysLT receptor 2 expression was increased. In contrast, the Toll-like receptor 3 agonist poly inosinic and cytidylic acid (polyI:C) had no effect on receptor expression. Downregulation of CysLT1 expression by LPS could not be mimicked by TNF-alpha alone or in combination with IL-1beta or IL-6. It was, however, prevented by inhibitors of COX and could be reproduced by a combination of TNF-alpha and prostaglandin E2. Immature DCs and DCs matured with polyI:C, but not with LPS, responded to LTD4 with a robust cytosolic calcium flux, which was prevented by the CysLT1 antagonist montelukast. LTD4 induced DC chemotaxis and enhanced DC migration in response to CCL19 in DCs matured with polyI:C, but only weakly in DCs matured with LPS. CONCLUSION: Our data suggest that human DCs may differentially respond to leukotriene, depending on their maturational stimuli. CLINICAL IMPLICATIONS: Our study demonstrates that some microbial agents can reduce the migration of dendritic cells in response to leukotrienes, with potential for differential involvement of these cells in allergic inflammation.     

Toll样受体在人乳头瘤病毒感染致宫颈癌中的作用

高危型人乳头瘤病毒(high-risk human papillomavirus,HR-HPV)持续感染是宫颈癌发生的明确病因,但并非所有HR-HPV感染都会导致宫颈癌,说明多种因素参与调节HR-HPV的致病性。Toll样受体(Toll-like receptors,TLRs)是一类模式识别受体,能特异性识别病原体相关...     

Functional characterization of histamine H4 receptor on human mast cells

Among the four different types of histamine receptors (H1-H4), H4R is predominantly expressed in immune cells and involved in immunomodulatory response. Here, in this study we determined the expression of H4R in human mast cells (HMC-1, LAD-2 and primary cord blood derived CD34+ human mast cells) and characterized its functional properties. Interestingly, we found that human mast cells responded to both histamine (natural ligand) and 4-methylhistamine (selective H4R agonist) for sustained intracellular calcium mobilization, degranulation and cytokine production. However, only histamine induced the release of cAMP, but 4-methylhistamine down regulates cAMP indicating that H4R mediates its effect through Gαi/o protein and H1R via Gαq protein. Furthermore, both histamine and 4-methylhistamine induced the production of cysteinyl leukotrienes and LTB4. Using human inflammation antibody array membrane, we found that H4R induced the expression of various inflammatory proteins, involving pro-inflammatory cytokines and chemokines and these are TGF-β1, TNF-α, TNF-β, PDGF-BB, TIMP-2, M-CSF, IP-10, IL-16, IL-6, IL-3, IL-10, MIP-1α, IL-1α, ICAM-1, Eotaxin-2, RANTES, IL-8, MCP-1, and IL-6sR. We also quantified the level of various inflammatory cytokines produced by human mast cells through H4R. It was observed that, the production level of Th2 cytokines IL-4(401.34 pg/ml), IL-5 (64.21 pg/ml) and IL-13 (1044 pg/ml) and classical proinflammatory cytokines IL-6 (221.27 pg/ml) and IL-1β (34.24 pg/ml) and chemokines MCP-1(106 pg/ml) and IL-8 (818.32 pg/ml). Furthermore, activation of H4R caused the phosphorylation of ERK and PI3 K in a time dependent manner. Taken together these data demonstrate that, the activation of H4R in human mast cells produced not only inflammatory mediators that are associated with allergic reactions but also other inflammatory conditions.     

Toll-like receptor 4-mediated activation of murine mast cells.

Toll-like receptors (TLRs) are a family of pattern recognition receptors that are critical for cellular responses to a variety of bacterial, viral, and fungal products. Mast cells are important to host survival in a number of models of bacterial infection and might act as sentinel cells in host defense. We therefore examined the expression of TLRs and associated molecules by murine bone marrow-derived mast cells (BMMCs). BMMCs and the murine mast cell line MC/9 expressed mRNA for TLR2, TLR4, and TLR6 but not TLR5 and for both adapter molecule MD-2 and signaling molecule MyD88 but lacked surface CD14. After activation with the TLR2- and TLR4-dependent stimuli Staphylococcus aureus-derived peptidoglycan and Escherichia coli-derived lipopolysaccharide (LPS), respectively, mast cells produced significant levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha). To determine whether mast cells require TLR4 for cellular responses to LPS, mast cells were derived from the bone marrow cells of C3H/HeJ and C57Bl/10ScNCr mice containing a point mutation and a null mutation, respectively, in TLR4. Using these models, we demonstrated that the BMMC IL-6 and TNF-alpha responses to LPS were completely dependent on functional TLR4 with no significant LPS response observed in its absence. These findings have important implications for the mechanism of mast cell responses to pathogens and their products and suggest that different TLR4-expressing cells might have different thresholds for activation with LPS.     

Quantification of mast cells in the uterine cervix of women infected with human immunodeficiency virus

The objective of the study was to identify mastocytosis in the chorionic epithelium of the uterine cervix in HIV-infected and non–HIV-infected women in autopsy specimens using histochemistry and immunohistochemistry techniques. Sixteen cervical tissue specimens were collected, of which 10 (62.50%) were from HIV-infected women. Histochemical and immunohistochemical techniques were used to evaluate mast cell density using Giemsa stain and anti-mast cell tryptase and anti-mast cell chymase antibodies, respectively. The study of the sheets and counting of mast cells with blue (Giemsa) or brown staining (anti-mast cell tryptase or chymase antibodies) were performed by 3 examiners, and 10 consecutive fields were examined under a light microscope at 400× magnification. A significant difference was found in mast cell density in the chorionic epithelium of the cervix in HIV-infected compared with non–HIV-infected women. The present study may contribute to the characterization of genital mucosa abnormalities and help better understand the potential role of mast cells in HIV-infected women.     

白细胞介素1β和白细胞介素17在根尖周病组织肥大细胞上的表达

 目的：观察不同类型慢性根尖周病组织中肥大细胞（mast cells, MCs）的分布情况,并分析白细胞介素1β（interleukin-1β,IL-1β）和白细胞介素17（interleukin-17,IL-17）在MCs上的表达情况,探讨MCs IL-1β和IL-17在根尖周病发病机制中的作用。方法：本实验共收集102例样本,分为3组：（1）根尖肉芽肿组32例;（2）根尖囊肿组35例;（3）正常对照组35例。组织标本经4%中性甲醛缓冲液固定48 h以上;石蜡包埋,组织连续切片,HE染色,在光学显微镜下观察其组织学改变;采用免疫荧光双染色法,在荧光显微镜下观察各组标本组织表达IL-1β和IL-17的MCs数目。结果：两组慢性根尖周病的炎症反应程度明显高于正常对照组（P<0.01）;根尖囊肿组与根尖肉芽肿组之间炎症反应程度无显著差异（P>0.05）。与正常对照组相比,两组慢性根尖周病组织中IL-1β和IL-17阳性MCs数目均显著增多（P<0.01）;根尖囊肿组与根尖肉芽肿组IL-1β和IL-17阳性MCs密度无显著性差异（P>0.05）。经Pearson相关分析,3组标本组织中IL-1β和IL-17阳性MCs密度与组织炎症反应程度存在直线的正相关关系（P<0.01）。结论：慢性根尖周病组织中MCs数目明显增多,同时IL-1β和IL-17阳性的MCs密度显著增高。IL-1β和IL-17阳性MCs密度与根尖周病的炎症程度趋势相一致。这提示IL-1β和IL-17阳性MCs可能在慢性根尖周病的致病机制中发挥重要作用。     

肝素通过TLR4减少脂多糖刺激的人内皮细胞IL-8表达

目的:观察肝素对脂多糖(lipopolysaccharide, LPS)刺激的人内皮细胞白细胞介素8(interleukin-8,IL-8)水平的影响,并探讨Toll样受体4(Toll-like receptor 4,TLR 4)在其中的可能影响。方法:用LPS(10 mg/L)刺激人肺微血管内皮细胞诱导损伤,肝素治疗组提前15 min分别加入100 U/L及10³ U/L普通肝素,正常对照组加入等量磷酸盐缓冲液。分别在刺激2、6、12 h收集细胞上清,采用酶联免疫吸附法测定上清中IL-8的浓度。在刺激2、6、12 h收集细胞提取RNA,应用实时荧光定量聚合酶链反应检测各组细胞中IL-8、CD14及TLR4 mRNA水平变化。结果:与正常对照组比较,LPS刺激组IL-8 mRNA水平增高,6 h达到高峰,其蛋白水平于12 h达到高峰。LPS刺激下TLR4 mRNA水平增高,6 h达到高峰,肝素降低其水平,差异有统计学意义(P＜0.05)。未检测到CD14 mRNA的表达。结论:LPS刺激下人肺微血管内皮细胞IL-8表达增加。肝素可能通过调节TLR4降低IL-8的水平,从而发挥保护作用。