BACKGROUND & AIMS:
:In cutaneous leishmaniasis, Leishmania amazonensis activates macrophage double-stranded, RNA-activated protein kinase R (PKR) to promote parasite growth. In our study, Leishmania major grew normally in RAW cells, RAW-expressing dominant-negative PKR (PKR-DN) cells, and macrophages of PKR-knockout mice, revealing that PKR is dispensable for L. major growth in macrophages. PKR activation in infected macrophages with poly I:C resulted in parasite death. Fifty percent of L. major-knockout lines for the ecotin-like serine peptidase inhibitor (ISP2; Δisp2/isp3), an inhibitor of neutrophil elastase (NE), died in RAW cells or macrophages from 129Sv mice, as a result of PKR activation. Inhibition of PKR or NE or neutralization of Toll-like receptor 4 or 2(TLR4 or TLR2) prevented the death of Δisp2/isp3. Δisp2/isp3 grew normally in RAW-PKR-DN cells or macrophages from 129Sv pkr(-/-), tlr2(-/-), trif(-/-), and myd88(-/-) mice, associating NE activity, PKR, and TLR responses with parasite death. Δisp2/isp3 increased the expression of mRNA for TNF-α by 2-fold and of interferon β (IFNβ) in a PKR-dependent manner. Antibodies to TNF-α reversed the 95% killing by Δisp2/isp3, whereas they grew normally in macrophages from IFN receptor-knockout mice. We propose that ISP2 prevents the activation of PKR via an NE-TLR4-TLR2 axis to control innate responses that contribute to the killing of L. major.-Faria, M. S., Calegari-Silva, T. C., de Carvalho Vivarini, A., Mottram, J. C., Lopes, U. G., Lima, A. P. C. A. Role of protein kinase R in the killing of Leishmania major by macrophages in response to neutrophil elastase and TLR4 via TNFα and IFNβ.
背景与目标:
: 在皮肤利什曼病中,亚马逊利什曼原虫激活巨噬细胞双链RNA激活的蛋白激酶R (PKR) 以促进寄生虫的生长。在我们的研究中,利什曼原虫major在原始细胞,原始表达的显性负PKR (PKR-DN) 细胞和巨噬细胞中正常生长PKR-敲除小鼠,表明PKR对于巨噬细胞的L. major生长是必不可少的。poly I:C感染的巨噬细胞中的PKR激活导致寄生虫死亡。作为PKR激活的结果,50% 的ecotin样丝氨酸肽酶抑制剂 (ISP2; Δisp2/isp3) (一种中性粒细胞弹性蛋白酶 (NE) 的抑制剂) 的L. major敲除品系死于129Sv小鼠的原始细胞或巨噬细胞。抑制PKR或NE或中和Toll样受体4或2(TLR4或TLR2) 可防止 Δisp2/isp3死亡。Δisp2/isp3在来自129Sv PKR (-/-),tlr2(-/-),trif(-/-) 和myd88(-/-) 小鼠的RAW-pkr-DN细胞或巨噬细胞中正常生长,使NE活性,PKR和TLR反应与寄生虫死亡。Δ isp2/isp3以PKR依赖性方式使TNF-α 的mRNA表达增加2倍,干扰素 β (ifn β) 的mRNA表达增加2倍。TNF-α 抗体逆转了 Δ isp2/isp3对95% 的杀伤,而它们在来自IFN受体敲除小鼠的巨噬细胞中正常生长。我们建议ISP2通过NE-TLR4-TLR2轴阻止PKR的激活,以控制有助于杀死L的先天反应。少校。-法里亚,男S、,卡莱加里-席尔瓦,T。C.,德卡瓦略·维瓦里尼,A.,莫特拉姆,JC.,洛佩斯,美国。G.,利马,A。P。C.A。蛋白激酶R在巨噬细胞通过tnf α 和ifn β 响应中性粒细胞弹性蛋白酶和TLR4杀死利什曼原虫中的作用。