Abstract
Aspergillus fumigatus causes most of aspergillosis in clinic and comprehensive function analysis of its key protein would promote anti-aspergillosis. In a previous study, we speculated actin depolymerizing factor cofilin might be essential for A. fumigatus viability and found its overexpression upregulated oxidative response and cell wall polysaccharide synthesis of this pathogen. Here, we constructed a conditional cofilin mutant to determine the essential role of cofilin. And the role of cofilin downregulation and phosphorylation in A. fumigatus was further analyzed. Cofilin was required for the polarized growth and heat sensitivity of A. fumigatus. Downregulation of cofilin caused hyphal cytoplasmic leakage, increased the sensitivity of A. fumigatus to sodium dodecyl sulfonate but not to calcofluor white and Congo Red and farnesol, and enhanced the basal phosphorylation level of MpkA, suggesting that cofilin affected the cell wall integrity (CWI) signaling. Downregulation of cofilin also increased the sensitivity of A. fumigatus to alkaline pH and H2O2. Repressing cofilin expression in A. fumigatus lead to attenuated virulence, which manifested as lower adherence and internalization rates, weaker host inflammatory response and shorter survival rate in a Galleria mellonella model. Expression of non-phosphorylated cofilin with a mutation of S5A had little impacts on A. fumigatus, whereas expression of a mimic-phosphorylated cofilin with a mutation of S5E resulted in inhibited growth, increased phospho-MpkA level, and decreased pathogenicity. In conclusion, cofilin is crucial to modulating the polarized growth, stress response, CWI and virulence of A. fumigatus.
Highlights
Aspergillus fumigatus is an important pathogenic fungus and causes 90% of aspergillosis
When cofilinteton was cultured in solid Aspergillus minimal medium (AMM) containing lower concentration of doxycycline (10 μg ml−1), its hyphal tips were irregular and hyperbranched compared to WT, which indicated downregulation of cofilin impaired the polarized growth of A. fumigatus at different temperatures, 28, 37, 48◦C (Figure 2A)
Cofilin Is Essential for the Viability of Aspergillus fumigatus
Summary
Aspergillus fumigatus is an important pathogenic fungus and causes 90% of aspergillosis. The actin-cytoskeleton regulatory proteins of fungi play a role in spore production, hyphal growth, stress response, cell wall integrity (CWI). Renshaw et al (2016) have recently showed that deletion of myosin B and myosin E of A. fumigatus displays abnormal septation, reduced growth, increased sensitivity to cell wall stressors and hypovirulence. We have constructed a cofilin overexpressing strain (cofilin OE) and found that overexpression of cofilin in A. fumigatus could increase the resistance to oxidative stress, and change the cell wall components and host inflammatory response. To further explore the function of cofilin in A. fumigatus, we first established a strain conditionally expressing the cofilin under the control of doxycycline-controlled tet-on promoter in this study. Downregulation of cofilin in A. fumigatus resulted in impaired polarized growth and CWI, increased sensitivity to alkaline pH and oxidative stresses, and hypovirulence. Cofilin phosphorylation plays a critical role on the growth and MpkA activation of A. fumigatus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
