Involvement of secreted Aspergillus fumigatus proteases in disruption of the actin fiber cytoskeleton and loss of focal adhesion sites in infected A549 lung pneumocytes
Involvement of secreted Aspergillus fumigatus proteases in disruption of the actin fiber cytoskeleton and loss of focal adhesion sites in infected A549 lung pneumocytes
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DOI：
10.1086/420850
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发表时间：
2004-06-01
影响因子：
6.4
通讯作者：
Osherov, N
中科院分区：
文献类型：
--
作者：
Kogan, TV;Jadoun, J;Osherov, N
烟曲霉是一种主要感染呼吸系统的机会致病真菌。肺泡上皮细胞的穿透是感染过程中的关键步骤。肺泡上皮细胞的细胞骨架形成细胞与其周围环境之间形成物理屏障的细胞基础。本研究着重探讨了A.烟曲霉对A549肺细胞肌动蛋白细胞骨架的影响。3个主要类别的细胞骨架纤维-肌动蛋白微丝，微管，和中间体-只有肌动蛋白细胞骨架被发现进行重大的结构变化，在响应感染，包括肌动蛋白应力纤维的损失，形成肌动蛋白聚集体，破坏粘着斑网站，和细胞起泡。这些变化在野生型A.通过添加丝氨酸和半胱氨酸蛋白酶抑制剂antipain，对烟曲霉的诱导作用，而不受碱性丝氨酸蛋白酶缺陷型菌株的诱导。烟熏。抗疼痛药也减少了真菌诱导的A549细胞从平板上脱落和活力降低，减少幅度接近50%。我们的研究结果表明，A.烟曲霉通过分泌蛋白酶破坏肺泡上皮细胞屏障，所述蛋白酶一起作用以破坏肌动蛋白细胞骨架并通过破坏粘着斑破坏细胞与基质的附着。
Aspergillus fumigatus is an opportunistic pathogenic fungus that predominantly infects the respiratory system. Penetration of the lung alveolar epithelium is a key step in the infectious process. The cytoskeleton of alveolar epithelial cells forms the cellular basis for the formation of a physical barrier between the cells and their surroundings. This study focused on the distinct effects of A. fumigatus on the actin cytoskeleton of A549 lung pneumocytes. Of the 3 major classes of cytoskeletal fibers-actin microfilaments, microtubules, and intermediate filaments-only the actin cytoskeleton was found to undergo major structural changes in response to infection, including loss of actin stress fibers, formation of actin aggregates, disruption of focal adhesion sites, and cell blebbing. These changes could be specifically blocked in wild-type strains of A. fumigatus by the addition of antipain, a serine and cysteine protease inhibitor, and were not induced by an alkaline serine protease-deficient strain of A. fumigatus. Antipain also reduced, by similar to50%, fungal-induced A549 cell detachment from the plates and reduction in viability. Our findings suggest that A. fumigatus breaches the alveolar epithelial cell barrier by secreting proteases that act together to disorganize the actin cytoskeleton and destroy cell attachment to the substrate by disrupting focal adhesions.