機(jī)體中的蛋白質(zhì)對(duì)于維持機(jī)體對(duì)細(xì)菌的免疫反應(yīng)至關(guān)重要,，而且部分蛋白質(zhì)可以保護(hù)機(jī)體免于自身的免疫效應(yīng)傷害,。近日來(lái)自耶魯大學(xué)的研究者研究了一種名為殼多糖酶3（Chi3l1）的一種蛋白質(zhì)，因?yàn)檫@種蛋白質(zhì)是存在于植物,、昆蟲(chóng)以及人類(lèi)機(jī)體中的一種古老家族的蛋白質(zhì),。進(jìn)化上的保守性使得科學(xué)家認(rèn)為Chi3l1在生物機(jī)體中扮演著重要的角色。然而目前對(duì)于Chi3l1的研究非常之少,。
研究小組研究發(fā)現(xiàn),，當(dāng)小鼠缺乏這種蛋白質(zhì)并且暴露于肺炎鏈球菌的環(huán)境中時(shí)，小鼠機(jī)體中的炎癥水平會(huì)大幅提高,，機(jī)體會(huì)出現(xiàn)大幅的炎癥損傷和出血情況,，而且相比含有正常Chi3l1的蛋白質(zhì)的小鼠來(lái)說(shuō)，其致死率更高,。研究者表示,，這種蛋白質(zhì)可以幫助巨噬細(xì)胞清理機(jī)體中的病原菌。相關(guān)研究成果刊登在了國(guó)際著名雜志Cell Host & Microbe上,。
研究者同時(shí)發(fā)現(xiàn)Chi3l1可以抑制先天性免疫效應(yīng),，并且可以降低其損傷宿主組織的能力。近些年來(lái),，科學(xué)家們對(duì)于經(jīng)典免疫系統(tǒng)應(yīng)答的領(lǐng)域越來(lái)越興趣,，研究者Charles表示，尤其是對(duì)于只清楚機(jī)體細(xì)菌而不殺傷機(jī)體的經(jīng)典免疫系統(tǒng)應(yīng)答領(lǐng)域,，科學(xué)家們更為關(guān)注,。他們發(fā)現(xiàn)的分子或許可以幫助機(jī)體達(dá)到這種免疫平衡效應(yīng)。
（生物谷Bioon.com）
編譯自：Scientists pinpoint key ingredient in fighting pneumonia
doi:10.1016/j.chom.2012.05.017
PMC:
PMID:
Chitinase 3-like-1 Promotes Streptococcus pneumoniae Killing and Augments Host Tolerance to Lung Antibacterial Responses
Charles S. Dela Cruz, Wei Liu, Chuan Hua He, Adam Jacoby, Alex Gornitzky, Bing Ma, Richard Flavell, Chun Geun Lee, Jack A. Elias
Host antibacterial responses include mechanisms that kill bacteria, but also those that protect or tolerize the host to potentially damaging antibacterial effects. We determined that Chitinase 3-like-1 (Chi3l1), a conserved prototypic chitinase-like protein, is induced by Streptococcus pneumoniae and plays central roles in promoting bacterial clearance and mediating host tolerance. S. pneumoniae-infected Chi3l1 null mice exhibit exaggerated lung injury, inflammation and hemorrhage, more frequent bacterial dissemination, decreased bacterial clearance, and enhanced mortality compared to controls. Chi3l1 augments macrophage bacterial killing by inhibiting caspase-1-dependent macrophage pyroptosis and augments host tolerance by controlling inflammasome activation, ATP accumulation, expression of ATP receptor P2X7R, and production of thymic stromal lymphopoietin and type 1, type 2, and type 17 cytokines. These data demonstrate that Chi3l1 is induced during infection, where it promotes bacterial clearance while simultaneously augmenting host tolerance, and that these roles likely contributed to the retention of Chi3l1 over species and evolutionary time.
