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Cell Microbiol. 2018 Mar;20(3). doi: 10.1111/cmi.12802. Epub 2017 Dec 22.

Aspergillus fumigatus adhesion factors in dormant conidia revealed through comparative phenotypic and transcriptomic analyses.

Author information

1
Medical Mycology Research Center, Chiba University, Chiba, Japan.

Abstract

Aspergillus fumigatus is an important fungal pathogen of humans. Inhaled conidia of A. fumigatus adhere to pulmonary epithelial cells, causing opportunistic infection. However, little is known about the molecular mechanism of the adherence of resting conidia. Fungal molecules adhesive to host cells are presumed to be displayed on the conidial surface during conidial formation as a result of changes in gene expression. Therefore, we exhaustively searched for adhesion molecules by comparing the phenotypes and the gene expression profiles of A. fumigatus strains that have conidia showing either high or low adherence to human pulmonary A549 cells. Morphological observation suggested that strains that produce conidia of reduced size, hydrophobicity, or number show decreased adherence to A549 cells. K-means cluster analyses of gene expression revealed 31 genes that were differentially expressed in the high-adherence strains during conidial formation. We knocked out three of these genes and showed that the conidia of AFUA_4G01030 (encoding a hypothetical protein) and AFUA_4G08805 (encoding a haemolysin-like protein) knockout strains had significantly reduced adherence to host cells. Furthermore, the conidia of these knockout strains had lower hydrophobicity and fewer surface spikes compared to the control strain. We suggest that the selectively expressed gene products, including those we identified experimentally, have composite synergistic roles in the adhesion of conidia to pulmonary epithelial cells.

KEYWORDS:

fungi (aspergillus); infection; microbial-cell interaction; molecular genetic; transcriptomics; virulence

PMID:
29113011
PMCID:
PMC5838799
DOI:
10.1111/cmi.12802
[Indexed for MEDLINE]
Free PMC Article

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