Rac2 Functions in Both Neutrophils and Macrophages To Mediate Motility and Host Defense in Larval Zebrafish.
Rac2 Functions in Both Neutrophils and Macrophages To Mediate Motility and Host Defense in Larval Zebrafish.
复制标题
DOI：
10.4049/jimmunol.1600928
复制
发表时间：
2016-12-15
期刊：
影响因子：
--
通讯作者：
Huttenlocher A
中科院分区：
文献类型：
--
作者：
Rosowski EE;Deng Q;Keller NP;Huttenlocher A
白细胞运动是宿主防御反应所必需的。Rac家族Rho GTP酶与白细胞功能有关，然而不同Rac同种型在体内宿主防御中的不同作用仍不清楚。在这里，我们使用TALEN产生Rac 2缺陷的斑马鱼，以直接比较Rac 2在中性粒细胞和巨噬细胞中的运动性和对感染的反应中的体内作用。这种斑马鱼幼虫模型非常适合白细胞行为的实时成像，我们报告说，在rac 2 −/−幼虫中，中性粒细胞和巨噬细胞的基本运动能力都有缺陷，导致对局部伤口或感染的反应受损。rac 2 −/−幼虫对铜绿假单胞菌的感染高度敏感，这几乎可以通过特异性地在中性粒细胞中异位表达Rac 2或Rac 1来完全拯救，这表明这些同种型在体内具有部分重叠的功能。拯救Rac 2表达，特别是在巨噬细胞也赋予耐假单胞菌感染，突出了Rac 2在这个白细胞群体中的重要作用。令人惊讶的是，与表达Rac 2显性抑制性人类疾病突变的中性粒细胞相反，rac 2 −/−中性粒细胞没有改变极性或从造血组织动员，这表明不同的Rac同种型，如Rac 1，也有助于体内这些表型。
Leukocyte motility is required for host defense responses. Rac-family Rho GTPases are implicated in leukocyte function, however the distinct roles of different Rac isoforms in host defense in vivo have remained unclear. Here, we generated Rac2-deficient zebrafish using TALENs in order to directly compare the role of Rac2 in vivo in neutrophils and macrophages in motility and the response to infection. This zebrafish larval model is highly amenable to live imaging of leukocyte behavior and we report that in rac2−/− larvae both neutrophils and macrophages are defective in basic motility, leading to impaired responses to localized wounds or infections. rac2−/− larvae are highly susceptible to infection with Pseudomonas aeruginosa which can be almost fully rescued by ectopic expression of either Rac2 or Rac1 specifically in neutrophils, indicating that these isoforms have partially overlapping functions in vivo. Rescue of Rac2 expression specifically in macrophages also confers resistance to Pseudomonas infection, highlighting an important role for Rac2 in this leukocyte population as well. Surprisingly, in contrast to neutrophils expressing a Rac2 dominant inhibitory human disease mutation, rac2−/− neutrophils do not have altered polarity or mobilization from hematopoietic tissue, suggesting that a different Rac isoform, such as Rac1, also contributes to these phenotypes in vivo.