PDF(Pubmed)
Abstract：
During the initiation of invasive aspergillosis, inhaled Aspergillus fumigatus conidia are deposited on the epithelial cells lining the bronchi, terminal bronchioles, and alveoli. While the interactions of A. fumigatus with bronchial and type II alveolar cell lines have been investigated in vitro, little is known about the interactions of this fungus with terminal bronchiolar epithelial cells. Using the HSAEC1-KT human small airway epithelial (HSAE) cell line, we developed an in vitro model to study the interaction of two strains of A. fumigatus with these cells. We then compared the interactions of A. fumigatus with the A549 type II alveolar epithelial cell line and the HSAE cell line. We found that A. fumigatus conidia were poorly endocytosed by A549 cells, but avidly endocytosed by HSAE cells. A. fumigatus germlings invaded both cell types by induced endocytosis, but not by active penetration. A549 cell endocytosis of A. fumigatus was independent of fungal viability, more dependent on host microfilaments than microtubules, and induced by A. fumigatus CalA interacting with host cell integrin α5β1. By contrast, HSAE cell endocytosis required fungal viability, was more dependent on microtubules than microfilaments, and did not require CalA or integrin α5β1. HSAE cells were more susceptible than A549 cells to damage caused by direct contact with killed A. fumigatus germlings and by secreted fungal products. In response to A. fumigatus infection, A549 cells secreted a broader profile of cytokines and chemokines than HSAE cells. Taken together, these results demonstrate that studies of HSAE cells provide complementary data to A549 cells and thus represent a useful model for probing the interactions of A. fumigatus with bronchiolar epithelial cells in vitro. Importance During the initiation of invasive aspergillosis, Aspergillus fumigatus interacts with the epithelial cells that line the airways and alveoli. Previous studies of A. fumigatus-epithelial cell interactions in vitro used either large airway epithelial cell lines or the A549 type II alveolar epithelial cell line; the interactions of fungi with terminal bronchiolar epithelial cells were not investigated. Using the TERT-immortalized human small airway epithelial HSAEC1-KT (HSAE) cell line, we developed an in vitro model of the interactions of A. fumigatus with bronchiolar epithelial cells. We discovered that A. fumigatus invades and damages A549 and HSAE cell lines by distinct mechanisms. Also, the proinflammatory responses of the cell lines to A. fumigatus are different. These results provide insight into how A. fumigatus interacts with different types of epithelial cells during invasive aspergillosis and demonstrate that HSAE cells are useful in vitro model for investigating the interactions of this fungus with bronchiolar epithelial cells.
摘要：
在侵袭性曲霉病开始时,吸入的烟曲霉分生孢子沉积在支气管衬里的上皮细胞上，终末细支气管，和肺泡.虽然已经在体外研究了烟曲霉与支气管和II型肺泡细胞系的相互作用，对这种真菌与终末细支气管上皮细胞的相互作用知之甚少。使用HSAEC1-KT人小气道上皮（HSAE）细胞系，我们建立了一个体外模型来研究两种烟曲霉与这些细胞的相互作用。然后我们比较了烟曲霉与A549II型肺泡上皮细胞系和HSAE细胞系的相互作用。我们发现烟曲霉分生孢子被A549细胞内吞不良，但被HSAE细胞强烈内吞。烟曲霉通过诱导内吞作用侵入两种细胞类型，但不是通过主动渗透。烟曲霉的A549细胞内吞作用与真菌活力无关，比微管更依赖宿主微丝，并由烟曲霉CalA与宿主细胞整合素α5β1相互作用诱导。相比之下,HSAE细胞内吞需要真菌活力，比微丝更依赖微管，并且不需要CalA或整合素α5β1。HSAE细胞比A549细胞更容易受到由直接接触杀死的烟曲霉幼苗和分泌的真菌产物引起的损伤。为了应对烟曲霉感染，A549细胞比HSAE细胞分泌更广泛的细胞因子和趋化因子。一起来看,这些结果表明，对HSAE细胞的研究提供了与A549细胞互补的数据，因此代表了在体外探测烟曲霉与细支气管上皮细胞相互作用的有用模型。重要性在侵袭性曲霉病开始期间，烟曲霉与气道和肺泡的上皮细胞相互作用。先前对烟曲霉与上皮细胞相互作用的体外研究使用了大型气道上皮细胞系或A549II型肺泡上皮细胞系；真菌与终末细支气管上皮细胞的相互作用没有研究。使用TERT永生化人小气道上皮HSAEC1-KT（HSAE）细胞系，我们建立了烟曲霉与细支气管上皮细胞相互作用的体外模型。我们发现烟曲霉通过不同的机制侵入和破坏A549和HSAE细胞系。此外，细胞系对烟曲霉的促炎反应是不同的。这些结果提供了关于烟曲霉在侵袭性曲霉病期间如何与不同类型的上皮细胞相互作用的见解，并证明HSAE细胞在体外模型中可用于研究这种真菌与细支气管上皮细胞的相互作用。
