新孢子蟲(chóng)激活宿主EGFR信號(hào)轉(zhuǎn)導(dǎo)調(diào)控細(xì)胞凋亡的分子機(jī)制
發(fā)布時(shí)間：2019-03-17 13:54
【摘要】：犬新孢子蟲(chóng)(Neospora caninum)屬于頂復(fù)門(mén),是一種專門(mén)寄生于哺乳宿主細(xì)胞內(nèi)的致病性原蟲(chóng)。它能感染大多數(shù)哺乳類動(dòng)物,其中對(duì)牛的危害最為嚴(yán)重。肉牛或奶牛感染N.caninum主要引起流產(chǎn),給全世界養(yǎng)牛業(yè)帶來(lái)巨大的經(jīng)濟(jì)損失。然而,N.caninum的細(xì)胞感染機(jī)制還沒(méi)有被完全闡明,尤其N.caninum對(duì)宿主信號(hào)轉(zhuǎn)導(dǎo)和細(xì)胞生存或死亡的調(diào)控機(jī)制報(bào)道甚少。EGFR(epidermal growth factor receptor)通路是參與細(xì)胞存活調(diào)控的重要信號(hào)通路。已經(jīng)有報(bào)道弓形蟲(chóng)能夠抑制感染細(xì)胞的凋亡;弓形蟲(chóng)感染激活EGFR-AKT信號(hào)通路,抑制自噬蛋白對(duì)蟲(chóng)體的靶標(biāo)和殺傷作用。但在新孢子蟲(chóng),是否其感染能夠調(diào)控EGFR信號(hào)報(bào)道較少,能否通過(guò)EGFR信號(hào)轉(zhuǎn)導(dǎo)控制宿主細(xì)胞的凋亡仍未知。因此,在本文中我們將針對(duì)N.caninum對(duì)宿主EGFR信號(hào)轉(zhuǎn)導(dǎo)通路及細(xì)胞凋亡調(diào)控的分子機(jī)制作詳細(xì)的研究,論文包括以下幾個(gè)部分:1.通過(guò)對(duì)新孢子蟲(chóng)刺激后宿主EGFR通路信號(hào)蛋白和凋亡相關(guān)蛋白的表達(dá)檢測(cè),結(jié)果表明N.caninum感染能迅速激活宿主EGFR、EGFR-AKT和EGFR-MAPK信號(hào)通路,進(jìn)而調(diào)控凋亡相關(guān)蛋白的表達(dá);2.通過(guò)對(duì)細(xì)胞凋亡相關(guān)指標(biāo)的檢測(cè),評(píng)估新孢子蟲(chóng)感染對(duì)宿主細(xì)胞活力和細(xì)胞凋亡的影響。結(jié)果發(fā)現(xiàn),N.caninum感染早期能夠抑制細(xì)胞凋亡,且其對(duì)凋亡的抑制主要通過(guò)EGFR-AKT通路的活化介導(dǎo);3.對(duì)新孢子蟲(chóng)激活EGFR信號(hào)轉(zhuǎn)導(dǎo)和抑制細(xì)胞凋亡的分子機(jī)制進(jìn)行了探討,結(jié)果發(fā)現(xiàn)N.caninum通過(guò)EGF-MIC和宿主細(xì)胞表面EGF受體的互作,激活宿主EGFR信號(hào)轉(zhuǎn)導(dǎo),進(jìn)而抑制細(xì)胞凋亡;4.使用特異性抑制劑、siRNA阻斷和干預(yù)宿主EGFR通路后,對(duì)新孢子蟲(chóng)細(xì)胞感染的影響進(jìn)行了檢測(cè),結(jié)果表明抑制EGFR信號(hào)通路的活化或沉默EGFR、AKT后,新孢子蟲(chóng)的細(xì)胞感染被顯著抑制;總之,本研究對(duì)新孢子蟲(chóng)調(diào)控細(xì)胞凋亡的分子機(jī)制進(jìn)行了探討,結(jié)果發(fā)現(xiàn):N.caninum感染能夠抑制宿主細(xì)胞凋亡,并且其對(duì)凋亡的抑制是通過(guò)含EGF樣結(jié)構(gòu)域的微線蛋白(EGF-MIC)來(lái)發(fā)揮作用的,N.caninum MIC-EGF通過(guò)與宿主EGFR的互作,介導(dǎo)EGFR-AKT信號(hào)通路的活化,并進(jìn)一步調(diào)控凋亡相關(guān)蛋白的表達(dá),結(jié)果發(fā)揮抑制細(xì)胞凋亡的效應(yīng)。這些新的信息將有助于我們更深入地認(rèn)識(shí)EGFR信號(hào)轉(zhuǎn)導(dǎo)在蟲(chóng)體感染過(guò)程中的功能及新孢子蟲(chóng)的細(xì)胞感染和生存機(jī)制;為新孢子蟲(chóng)參與宿主功能的調(diào)控提供了理論依據(jù),對(duì)今后尋找和設(shè)計(jì)用于化學(xué)干預(yù)新孢子蟲(chóng)病的有效藥物具有重要意義。
[Abstract]:Neosporidium canis (Neospora caninum) is a kind of pathogenic protozoa that parasitize the host cells of lactation. It can infect most mammals, among which the most serious harm to cattle. Beef cattle or cows infected with N.caninum mainly cause abortion and bring huge economic losses to cattle industry all over the world. However, the mechanism of N.caninum cell infection has not been fully clarified. In particular, there are few reports on the regulation of host signal transduction and cell survival or death by N.caninum. EGFR (epidermal growth factor receptor) pathway is an important signal pathway involved in the regulation of cell survival. It has been reported that Toxoplasma gondii can inhibit the apoptosis of infected cells and that Toxoplasma gondii infection activates EGFR-AKT signaling pathway and inhibits the target and killing effect of autophagy protein on infected cells. However, in Neosporidium, whether the infection can regulate the EGFR signal is less reported, whether the EGFR signal transduction can control the apoptosis of host cells is still unknown. Therefore, in this paper, we will make a detailed study of the molecular mechanism of N.caninum on the host EGFR signal transduction pathway and apoptosis regulation. The thesis includes the following parts: 1. After stimulation with neosporidium, the expression of EGFR signaling protein and apoptosis-related protein in host was detected. The results showed that N.caninum infection could activate the EGFR,EGFR-AKT and EGFR-MAPK signaling pathway of host rapidly, and then regulate the expression of apoptosis-related protein. 2. The effect of Neosporidium infection on cell viability and apoptosis was evaluated by detecting apoptosis-related indexes. The results showed that N.caninum infection could inhibit apoptosis in early stage, and its inhibition was mainly mediated by activation of EGFR-AKT pathway. The molecular mechanism of neosporidium activating EGFR signal transduction and inhibiting cell apoptosis was discussed. The results showed that N.caninum could activate host EGFR signal transduction through interaction between EGF-MIC and host cell surface EGF receptor, and then inhibit cell apoptosis; 4. The effects of siRNA on Neosporidium cell infection were detected after blocking and interfering the host EGFR pathway with specific inhibitors. The results showed that after inhibiting the activation of EGFR signaling pathway or silencing EGFR,AKT, the cell infection of Neosporidium was significantly inhibited. In conclusion, this study discussed the molecular mechanism of neosporidium regulating cell apoptosis. The results showed that N.caninum infection could inhibit the apoptosis of host cells. The inhibition of apoptosis is mediated by the EGF-like domain EGF-MIC, which mediates the activation of the EGFR-AKT signaling pathway by interacting with the host EGFR. And further regulate the expression of apoptosis-related proteins, resulting in the inhibition of cell apoptosis effect. These new information will help us to further understand the function of EGFR signal transduction in the process of parasite infection and the cell infection and survival mechanism of Neosporidium. It provides a theoretical basis for neosporidium to participate in the regulation of host function, and it is of great significance to find and design effective drugs for chemical intervention of neosporidiosis in the future.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：S852.7
本文編號(hào)：2442363
[Abstract]:Neosporidium canis (Neospora caninum) is a kind of pathogenic protozoa that parasitize the host cells of lactation. It can infect most mammals, among which the most serious harm to cattle. Beef cattle or cows infected with N.caninum mainly cause abortion and bring huge economic losses to cattle industry all over the world. However, the mechanism of N.caninum cell infection has not been fully clarified. In particular, there are few reports on the regulation of host signal transduction and cell survival or death by N.caninum. EGFR (epidermal growth factor receptor) pathway is an important signal pathway involved in the regulation of cell survival. It has been reported that Toxoplasma gondii can inhibit the apoptosis of infected cells and that Toxoplasma gondii infection activates EGFR-AKT signaling pathway and inhibits the target and killing effect of autophagy protein on infected cells. However, in Neosporidium, whether the infection can regulate the EGFR signal is less reported, whether the EGFR signal transduction can control the apoptosis of host cells is still unknown. Therefore, in this paper, we will make a detailed study of the molecular mechanism of N.caninum on the host EGFR signal transduction pathway and apoptosis regulation. The thesis includes the following parts: 1. After stimulation with neosporidium, the expression of EGFR signaling protein and apoptosis-related protein in host was detected. The results showed that N.caninum infection could activate the EGFR,EGFR-AKT and EGFR-MAPK signaling pathway of host rapidly, and then regulate the expression of apoptosis-related protein. 2. The effect of Neosporidium infection on cell viability and apoptosis was evaluated by detecting apoptosis-related indexes. The results showed that N.caninum infection could inhibit apoptosis in early stage, and its inhibition was mainly mediated by activation of EGFR-AKT pathway. The molecular mechanism of neosporidium activating EGFR signal transduction and inhibiting cell apoptosis was discussed. The results showed that N.caninum could activate host EGFR signal transduction through interaction between EGF-MIC and host cell surface EGF receptor, and then inhibit cell apoptosis; 4. The effects of siRNA on Neosporidium cell infection were detected after blocking and interfering the host EGFR pathway with specific inhibitors. The results showed that after inhibiting the activation of EGFR signaling pathway or silencing EGFR,AKT, the cell infection of Neosporidium was significantly inhibited. In conclusion, this study discussed the molecular mechanism of neosporidium regulating cell apoptosis. The results showed that N.caninum infection could inhibit the apoptosis of host cells. The inhibition of apoptosis is mediated by the EGF-like domain EGF-MIC, which mediates the activation of the EGFR-AKT signaling pathway by interacting with the host EGFR. And further regulate the expression of apoptosis-related proteins, resulting in the inhibition of cell apoptosis effect. These new information will help us to further understand the function of EGFR signal transduction in the process of parasite infection and the cell infection and survival mechanism of Neosporidium. It provides a theoretical basis for neosporidium to participate in the regulation of host function, and it is of great significance to find and design effective drugs for chemical intervention of neosporidiosis in the future.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：S852.7
【相似文獻(xiàn)】
相關(guān)博士學(xué)位論文 前1條
1 靳小霞;新孢子蟲(chóng)激活宿主EGFR信號(hào)轉(zhuǎn)導(dǎo)調(diào)控細(xì)胞凋亡的分子機(jī)制[D];吉林大學(xué);2017年
，本文編號(hào)：2442363
本文鏈接：http://sikaile.net/shoufeilunwen/nykjbs/2442363.html
最近更新
教材專著
