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题名: 金黄色葡萄球菌脂蛋白通过TLR2引发人角膜上皮细胞免疫反应
作者: 李琼
答辩日期: 2008-05-28
导师: 桂建芳 ; 余福新
授予单位: 中国科学院水生生物研究所
授予地点: 水生生物研究所
学位: 硕士
关键词: 人角膜上皮细胞 ; TLR ; 天然免疫 ; 炎症 ; 信号传导
其他题名: Staphylococcus aureus lipoproteins trigger human corneal epithelial innate response through toll-like receptor-2.
摘要: 在由于长期配戴隐形眼镜造成感染性角膜炎的人群中,大概有四分之一的病例是由金黄色葡萄球菌引起的,并且最近金黄色葡萄球菌角膜炎患者的数量在中国和美国都呈现出逐渐增加的趋势。尽管角膜长期暴露在大量病原微生物的攻击下,它在通常情况下有很强的抗感染能力,但在某些情况下角膜上皮细胞会因佩戴隐形眼镜而刮伤,这时外源病原体如金黄色葡萄球菌就有机会入侵导致感染,因此位于防御病原微生物第一线的上皮细胞必须能够对入侵的病原体进行识别并发生适宜的免疫反应。目前已经证实上皮细胞和其他哺乳动物细胞对入侵微生物的识别包括了Toll样受体(TLR)的活化, TLR识别一系列病原相关的分子模式,细菌脂蛋白是众多细菌细胞壁的一类组成成分,研究发现它也是病原相关的分子模式中的一种。 在本研究中,我们用曲拉通X-114提取了金黄色葡萄球菌的脂蛋白(saLP),然后研究端粒酶永生化的人角膜上皮细胞(HCEC)系HUCL对提取自金黄色葡萄球菌的脂蛋白的反应。结果显示,saLP引起了HUCL细胞中NF-κB、JNK和P38信号途径的活化。该萃取物在脂蛋白脂肪酶处理后不能刺激HUCL细胞中NF-κB活化,且在表达活性TLR4的Hela细胞或表达TLR9的人胚肾上皮细胞中也不能刺激NF-κB活化,这表明了该萃取物的脂蛋白本性。saLP诱导了炎症细胞因子和趋化因子(IL-6、IL-8、ICAM-1)、抗菌分子(hBD2、LL-37和iNOS)以及动态平衡基因(Mn-SOD)在mRNA水平和蛋白水平上的上调。在原代培养细胞中也观察到saLP产生的以IL-6生成为指数的炎性反应。此外,TLR2中和抗体阻止了HUCL细胞中saLP诱导的IL-6、IL-8和hBD2分泌。我们的发现提示saLP通过促炎细胞因子和防御分子的产生来活化TLR2并产生眼角膜细胞对金黄色葡萄球菌感染的天然免疫反应。
英文摘要: Staphylococcus (S). aureus is a leading cause of infectious keratitis associated with extended wear of contact lenses, accounting for approximately one-quarter of confirmed cases, with a gradual increase recently in the number of S. aureus keratitis in both the US and China. Under normal condition, the cornea is highly resistant to infection despite its constant exposure to a wide array of microorganisms. To cause infection, the opportunistic bacteria such as S.aureus are likely to first confront the epithelium with compromised barrier such as that caused by contact lens wearing. The epithelial cells that form the first line of defense against microbial pathogens, in turn must be able to recognize and respond appropriately to the invading pathogen. It is now well-established fact that recognition of invading microorganisms by epithelial as well as other mammalian cells includes the action of the Toll-like receptor (TLR) family. It plays a central role in early innate immunity by sensing the presence of microbial pathogens and initiating a response to eliminate them. These receptors recognize the highly conserved structural motifs called pathogen-associated molecular patterns (PAMPs), Bacterial lipoproteins (LP) are one of the PAMPs, they are a family of cell wall components found in a wide variety of bacteria. In this study, we used Triton X-114 extraction method prepared LP isolated from S. aureus. S. aureus LP(saLP), then used it to stimulate HUCL cell, a telomerase -immortalized human corneal epithelial cell (HCEC) line. Our result showed that S. aureus LP(saLP) prepared by Triton X-114 extraction stimulated the activation of NF-κB, JNK, and P38 signaling pathways in HUCL cells. In HUCL cells after lipoprotein lipase treatment, or in human embryonic kidney (HEK) cell lines expressing functional TLR9, or in Hela cells expressing functional TLR4, the extracts failed to stimulate NF-κB activation, indicating lipoprotein nature of the extracts. saLP induced the up-regulation of a variety of inflammatory cytokines and chemokines (IL-6, IL-8, ICAM-1) and antimicrobial molecules (hBD-2, LL-37, and iNOS), and homeostasis genes (Mn-SOD) at both the mRNA level and protein level. Similar inflammatory response to saLP was also observed in primarily cultured HCECs using the production of IL-6 as readout. Moreover, TLR2 neutralizing antibody blocked the saLP-induced secretion of IL-6, IL-8 and hBD2 in HUCL cells. Our findings suggest that saLP activates TLR2 and contributes to innate immune response in the cornea to S. aureus infection via production of proinflammatory cytokines and defense molecules.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.ihb.ac.cn/handle/342005/12074
Appears in Collections:中科院水生所知识产出(2009年前)_学位论文

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Recommended Citation:
金黄色葡萄球菌脂蛋白通过TLR2引发人角膜上皮细胞免疫反应.李琼[d].中国科学院水生生物研究所,2008.20-25
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