The innate immune system of insects is divided into humoral defenses that include the production of soluble effector molecules and cellular defenses like phagocytosis and encapsulation that are mediated by hemocytes. ...The innate immune system of insects is divided into humoral defenses that include the production of soluble effector molecules and cellular defenses like phagocytosis and encapsulation that are mediated by hemocytes. This review summarizes current understand- ing of the cellular immune response. Insects produce several terminally differentiated types of hemocytes that are distinguished by morphology, molecular and antigenic markers, and function. The differentiated hemocytes that circulate in larval or nymphal stage insects arise from two sources： progenitor cells produced during embryogenesis and mesodermally derived hematopoietic organs. Regulation of hematopoiesis and hemocyte differentiation also involves several different signaling pathways. Phagocytosis and encapsulation require that hemocytes first recognize a given target as foreign followed by activation of downstream signaling and effector responses. A number of humoral and cellular receptors have been identified that recognize different microbes and multicellular parasites. In turn, activation of these receptors stimulates a number of signaling pathways that regulate different hemocyte functions. Recent studies also identify hemocytes as important sources Of a number of humoral effector molecules required for killing different foreign invaders.展开更多
背景:抗菌肽作为一种可从自然来源提取并用于对抗抗生素耐药细菌的潜在候选物,引起了科学家们的广泛关注,熟悉抗菌肽的抗菌机制有利于将抗菌肽的临床应用。目的:综述近年来对抗菌肽抗菌机制的研究进展。方法:由第一作者应用计算机检索Pu...背景:抗菌肽作为一种可从自然来源提取并用于对抗抗生素耐药细菌的潜在候选物,引起了科学家们的广泛关注,熟悉抗菌肽的抗菌机制有利于将抗菌肽的临床应用。目的:综述近年来对抗菌肽抗菌机制的研究进展。方法:由第一作者应用计算机检索PubMed、Springerlink、Web of Science、ScienceDirect等数据库2013年1月至2019年3月发表的文献,选择与抗菌肽抗菌机制及其研究进展相关的文献。结果与结论:抗菌肽是一类特殊的分子,为具有广谱抗菌性的宿主防御多肽,在一些生物体中其被认为是先天免疫系统的重要组成部分。抗菌肽的抗菌机制从作用模式上可以分为直接致死和免疫调节2类主要的模式,直接致死作用机制可进一步分为膜靶向和非膜靶向。与此同时基于抗菌肽的广泛应用,预计在葡萄球菌、口腔细菌(包括链球菌)和肠道细菌(包括沙门氏菌)等微生物环境中已发展出许多抵抗策略,主要分为被动抵抗和诱导或适应性抵抗机制。在未来的研究和应用中,阳离子肽是解决多重耐药性日益增多的一个有效选择,除了应设计新的方法来对抗细菌对抗菌肽的耐药性外,也应该预防由常规抗生素产生的耐药性。展开更多
Inflammasomes are important for maintaining intestinal homeostasis, and dysbiosis contributes to the pathology of inflammatory bowel disease （IBD） and increases the risk for colorectal cancer, Inflammasome defects c...Inflammasomes are important for maintaining intestinal homeostasis, and dysbiosis contributes to the pathology of inflammatory bowel disease （IBD） and increases the risk for colorectal cancer, Inflammasome defects contribute to chronic intestinal inflammation and increase the susceptibility to colitis in mice, However, the inflammasome sensor absent in melanoma 2 （AIM2） protects against coiorectal cancer in an inflammasome-independent manner through DNA-dependent protein kinase and Akt pathways, Yet, the roles of the AIM2 inflammasome in IBD and the early phases of colorectal cancer remain ill-defined, Here we show that the AIM2 inflammasome has a protective role in the intestine, During steady state, Aim2 deletion results in the loss of IL-18 secretion, suppression of the IL-22 binding protein （IL-22BP） in intestinal epithelial cells and consequent loss of the STAT3-dependent antimicrobial peptides （AMPs） Reg3β and Reg3γ, which promotes dysbiosis-linked colitis, During dextran sulfate sodium-induced colitis, a dysfunctional IL-18/IL-22BP pathway in Aim2^-/- mice promotes excessive IL-22 production and elevated STAT3 activation, Aim2^-/- mice further exhibit sustained STAT3 and Akt activation during the resolution of colitis fueled by enhanced Reg3b and Reg3g expression, This self-perpetuating mechanism promotes proliferation of intestinal crypt cells and likely contributes to the recently described increase in susceptibility of Aim2^-/- mice to colorectal cancer, Collectively, our results demonstrate a central role for the AIM2 inflammasome in preventing dysbiosis and intestinal inflammation through regulation of the IL-18/IL-22BP/IL-22 and STAT3 pathway and expression of select AMPs.展开更多
文摘The innate immune system of insects is divided into humoral defenses that include the production of soluble effector molecules and cellular defenses like phagocytosis and encapsulation that are mediated by hemocytes. This review summarizes current understand- ing of the cellular immune response. Insects produce several terminally differentiated types of hemocytes that are distinguished by morphology, molecular and antigenic markers, and function. The differentiated hemocytes that circulate in larval or nymphal stage insects arise from two sources： progenitor cells produced during embryogenesis and mesodermally derived hematopoietic organs. Regulation of hematopoiesis and hemocyte differentiation also involves several different signaling pathways. Phagocytosis and encapsulation require that hemocytes first recognize a given target as foreign followed by activation of downstream signaling and effector responses. A number of humoral and cellular receptors have been identified that recognize different microbes and multicellular parasites. In turn, activation of these receptors stimulates a number of signaling pathways that regulate different hemocyte functions. Recent studies also identify hemocytes as important sources Of a number of humoral effector molecules required for killing different foreign invaders.
文摘背景:抗菌肽作为一种可从自然来源提取并用于对抗抗生素耐药细菌的潜在候选物,引起了科学家们的广泛关注,熟悉抗菌肽的抗菌机制有利于将抗菌肽的临床应用。目的:综述近年来对抗菌肽抗菌机制的研究进展。方法:由第一作者应用计算机检索PubMed、Springerlink、Web of Science、ScienceDirect等数据库2013年1月至2019年3月发表的文献,选择与抗菌肽抗菌机制及其研究进展相关的文献。结果与结论:抗菌肽是一类特殊的分子,为具有广谱抗菌性的宿主防御多肽,在一些生物体中其被认为是先天免疫系统的重要组成部分。抗菌肽的抗菌机制从作用模式上可以分为直接致死和免疫调节2类主要的模式,直接致死作用机制可进一步分为膜靶向和非膜靶向。与此同时基于抗菌肽的广泛应用,预计在葡萄球菌、口腔细菌(包括链球菌)和肠道细菌(包括沙门氏菌)等微生物环境中已发展出许多抵抗策略,主要分为被动抵抗和诱导或适应性抵抗机制。在未来的研究和应用中,阳离子肽是解决多重耐药性日益增多的一个有效选择,除了应设计新的方法来对抗细菌对抗菌肽的耐药性外,也应该预防由常规抗生素产生的耐药性。
文摘Inflammasomes are important for maintaining intestinal homeostasis, and dysbiosis contributes to the pathology of inflammatory bowel disease （IBD） and increases the risk for colorectal cancer, Inflammasome defects contribute to chronic intestinal inflammation and increase the susceptibility to colitis in mice, However, the inflammasome sensor absent in melanoma 2 （AIM2） protects against coiorectal cancer in an inflammasome-independent manner through DNA-dependent protein kinase and Akt pathways, Yet, the roles of the AIM2 inflammasome in IBD and the early phases of colorectal cancer remain ill-defined, Here we show that the AIM2 inflammasome has a protective role in the intestine, During steady state, Aim2 deletion results in the loss of IL-18 secretion, suppression of the IL-22 binding protein （IL-22BP） in intestinal epithelial cells and consequent loss of the STAT3-dependent antimicrobial peptides （AMPs） Reg3β and Reg3γ, which promotes dysbiosis-linked colitis, During dextran sulfate sodium-induced colitis, a dysfunctional IL-18/IL-22BP pathway in Aim2^-/- mice promotes excessive IL-22 production and elevated STAT3 activation, Aim2^-/- mice further exhibit sustained STAT3 and Akt activation during the resolution of colitis fueled by enhanced Reg3b and Reg3g expression, This self-perpetuating mechanism promotes proliferation of intestinal crypt cells and likely contributes to the recently described increase in susceptibility of Aim2^-/- mice to colorectal cancer, Collectively, our results demonstrate a central role for the AIM2 inflammasome in preventing dysbiosis and intestinal inflammation through regulation of the IL-18/IL-22BP/IL-22 and STAT3 pathway and expression of select AMPs.
