双歧杆菌胞壁蛋白诱导人肠腺上皮细胞β-防御素-2基因表达及其信号转导机制

发布时间：2018-01-01 00:33

本文关键词：双歧杆菌胞壁蛋白诱导人肠腺上皮细胞β-防御素-2基因表达及其信号转导机制　出处：《四川大学》2005年博士论文　论文类型：学位论文

【摘要】：消化道中定植有大量菌群,消化道上皮细胞与这些菌群直接接触,是肠道粘膜免疫的第一道防线,其分泌的抗菌肽分子在维持肠道微生态平衡、抵抗病原菌感染中占有重要地位。人β-防御素-2(hBD-2)是一重要的抗菌肽分子,广泛表达于皮肤、呼吸道、消化道、泌尿生殖道等粘膜上皮细胞中,具有重要的抗感染功能。hBD-2具有诱导表达的特点,通常情况下肠道上皮细胞不表达hBD-2,但在受到致病因子刺激时,hBD-2的表达量迅速提高,进而发挥粘膜保护功能。以往的研究显示病原菌如肠炎性沙门氏菌,侵袭性大肠杆菌等能够诱导人肠道上皮细胞hBD-2表达,但是益生菌与抗菌肽之间的关系还没有相关研究,而且hBD-2诱导表达的调控及其信号转导机制十分复杂,目前尚不完全清楚。双歧杆菌作为人体主要益生菌之一,参与了宿主的消化、营养、代谢、吸收、免疫及抗感染过程。因此通过探讨双歧杆菌与hBD-2表达之间的关系,寻找诱导hBD-2基因表达的有效刺激因子,不仅能够通过提高粘膜局部hBD-2浓度而达到杀灭病原菌的目的,而且有助于在分子水平上揭示机体抗感染免疫防御机制。本项研究目的是检测双歧杆菌对人肠腺上皮细胞hBD-2基因的激活作用并分离其活性组分,进一步探讨其受体及其胞内信号传导通路。首先,我们研究了双歧杆菌对人肠腺上皮细胞hBD-2基因的激活作用并分离其活性组分。厌氧培养长双歧杆菌,采用超声破碎细胞、超速离心、蛋白萃取方法获得双歧杆菌胞壁蛋白质成份,分别利用活菌,热灭活全菌,全
[Abstract]:There are a lot of colonization in the digestive tract microflora, digestive tract epithelial cells and these bacteria in direct contact, is the first line of defense of intestinal mucosal immunity, the secretion of antimicrobial peptides on intestinal micro ecological balance, resistance plays an important role in pathogen infection. Human beta defensin -2 (hBD-2) is one of the most important antibacterial peptide, is widely expressed in skin, respiratory, gastrointestinal, urogenital tract and other mucosal epithelial cells, has an important function of.HBD-2 has the characteristics of anti infection induced the expression of intestinal epithelial cells normally do not express hBD-2, but by the pathogenic factors of stimulation, the expression of hBD-2 increased rapidly, and then play the mucosa the protection function.
Previous studies have shown that the pathogens such as Salmonella enteritis, to invasive Escherichia coli hBD-2 induced by human intestinal epithelial cell expression, but the relationship between probiotics and antimicrobial peptides has not been studied, and the regulation of hBD-2 induced expression and signal transduction mechanism of ten complex, is not totally clear. As one of Bifidobacterium the main body involved in host probiotics, digestion, nutrition, metabolism, absorption, immunity and anti infection. Therefore, through discussing the relationship between the expression of hBD-2 and Bacillus bifidus, find effective stimulation factor induced hBD-2 gene expression, not only can to kill pathogens by improving mucosal hBD-2 concentration, but also help to reveal the body at the molecular level of anti infection immune defense mechanism.
The purpose of this study is to detect the activation of Bifidobacterium on hBD-2 gene of human intestinal epithelial cells and isolate their active components, and further explore their receptors and intracellular signaling pathways.
First, we studied the activation effect of Bifidobacterium on human intestinal epithelial cells hBD-2 gene and separation of active components. Anaerobic culture of Bifidobacterium longum, using ultrasonic cell, ultracentrifugation, protein extraction method of bifidobacterium cell wall protein content respectively by using heat inactivated bacteria, total bacteria, total

【学位授予单位】：四川大学
【学位级别】：博士
【学位授予年份】：2005
【分类号】：R37

【引证文献】