Abstract

Airway epithelium plays an important role as a physical barrier to infection and may also contribute to immunity by secreting cytokines. In this study we demonstrate the ability of Paracoccidioides brasiliensis to induce mRNA expression and secretion of inflammatory cytokines in human lung epithelial cells (A549). A549 cells were incubated with formaldehyde-fixed (FY) or live (LY) yeasts of P. brasiliensis for different periods of time (5-96h). Expression of IL-6, IL-8, TNF-α and IL-1β mRNA was analyzed by semiquantitative RT-PCR. For IL-1β and IL-8, it was observed a slight increase of mRNA levels in A549 cells incubated with FY and LY P. brasiliensis. On the other hand, it was verified that FY and LY P. brasiliensis were able to increase IL-6 mRNA expression by at least 2-fold over basal levels. Interestingly, only FY P. brasiliensis greatly increased TNF-α mRNA expression in A549 cells by at least 3-fold over basal levels. In order to verify if protein synthesis and secretion of cytokines matched with obtained results by RT-PCR, the supernatants of A549 cells incubated with FY and LY P. brasiliensis were analyzed using Quantikine kits. As expected, it was verified that P. brasiliensis was able to increase IL-6 and IL-8 secretion by A549 cells at least 5,9 and 1,3-fold over basal levels, respectively. Surprisingly, TNF-α and IL-1β secretion by A549 cells incubated with P. brasiliensis was not observed. Taking together, these results indicate that P. brasiliensis is able to induce mRNA expression and secretion of inflammatory cytokines in A549 cells, suggesting that pulmonary epithelial cells may participate in early host immune response in this fungal infection. Cell signaling pathways involved in this process are under investigation in our laboratory.਀匀甀瀀瀀漀爀琀攀搀 戀礀 䘀䄀倀䔀匀倀⸀ 㰀⼀昀漀渀琀㸀㰀⼀瀀㸀㰀戀爀㸀㰀戀㸀䬀攀礀眀漀爀搀㨀 㰀⼀戀㸀☀渀戀猀瀀㬀昀甀渀最甀猀ⴀ栀漀猀琀 椀渀琀攀爀愀挀琀椀漀渀Ⰰ 椀渀昀氀愀洀洀愀琀漀爀礀 挀礀琀漀欀椀渀攀猀Ⰰ 氀甀渀最 攀瀀椀琀栀攀氀椀愀氀 挀攀氀氀猀Ⰰ 倀愀爀愀挀漀挀挀椀搀椀漀椀搀攀猀 戀爀愀猀椀氀椀攀渀猀椀猀㰀⼀琀搀㸀㰀⼀琀爀㸀㰀⼀琀愀戀氀攀㸀㰀⼀琀爀㸀㰀⼀琀搀㸀㰀⼀琀愀戀氀攀㸀㰀⼀戀漀搀礀㸀㰀⼀栀琀洀氀㸀