Xisto Mariana I D S, Bittencourt Vera C B, Liporagi-Lopes Livia Cristina, Haido Rosa M T, Mendonça Morena S A, Sassaki Guilherme, Figueiredo Rodrigo T, Romanos Maria Teresa V, Barreto-Bergter Eliana
Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
Departamento de Microbiologia e Parasitologia, Instituto Biomédico, UNIRIO, Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2015 Apr 14;10(4):e0123189. doi: 10.1371/journal.pone.0123189. eCollection 2015.
In this study, we analyze the importance of O-linked oligosaccharides present in peptidorhamnomannan (PRM) from the cell wall of the fungus Scedosporium prolificans for recognition and phagocytosis of conidia by macrophages. Adding PRM led to a dose-dependent inhibition of conidia phagocytosis, whereas de-O-glycosylated PRM did not show any effect. PRM induced the release of macrophage-derived antimicrobial compounds. However, O-linked oligosaccharides do not appear to be required for such induction. The effect of PRM on conidia-induced macrophage killing was examined using latex beads coated with PRM or de-O-glycosylated PRM. A decrease in macrophage viability similar to that caused by conidia was detected. However, macrophage killing was unaffected when beads coated with de-O-glycosylated PRM were used, indicating the toxic effect of O-linked oligosaccharides on macrophages. In addition, PRM triggered TNF-α release by macrophages. Chemical removal of O-linked oligosaccharides from PRM abolished cytokine induction, suggesting that the O-linked oligosaccharidic chains are important moieties involved in inflammatory responses through the induction of TNF-α secretion. In summary, we show that O-glycosylation plays a role in the recognition and uptake of S. prolificans by macrophages, killing of macrophages and production of pro- inflammatory cytokines.
在本研究中，我们分析了多育赛多孢菌细胞壁肽聚糖甘露聚糖（PRM）中存在的O-连接寡糖对巨噬细胞识别和吞噬分生孢子的重要性。添加PRM导致分生孢子吞噬呈剂量依赖性抑制，而去O-糖基化的PRM则未显示任何作用。PRM诱导巨噬细胞衍生的抗菌化合物释放。然而，O-连接寡糖似乎并非这种诱导所必需。使用包被有PRM或去O-糖基化PRM的乳胶珠检测PRM对分生孢子诱导的巨噬细胞杀伤作用。检测到巨噬细胞活力下降，与分生孢子引起的情况相似。然而，当使用包被去O-糖基化PRM的珠子时，巨噬细胞杀伤不受影响，表明O-连接寡糖对巨噬细胞有毒性作用。此外，PRM触发巨噬细胞释放TNF-α。从PRM中化学去除O-连接寡糖消除了细胞因子诱导，表明O-连接寡糖链是通过诱导TNF-α分泌参与炎症反应的重要部分。总之，我们表明O-糖基化在巨噬细胞对多育赛多孢菌的识别和摄取、巨噬细胞杀伤以及促炎细胞因子产生中起作用。
