Limits...
Trehalose-mediated autophagy impairs the anti-viral function of human primary airway epithelial cells.

Wu Q, Jiang D, Huang C, van Dyk LF, Li L, Chu HW - PLoS ONE (2015)

Bottom Line: We found that trehalose-induced autophagy significantly impaired IFN-λ1 expression and increased HRV-16 load.Inhibition of autophagy via knockdown of autophagy-related gene 5 (ATG5) effectively rescued the impaired IFN-λ1 expression by trehalose and subsequently reduced HRV-16 load.Intervention of excessive autophagy in chronic lung diseases may provide a novel approach to attenuate viral infections and associated disease exacerbations.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, National Jewish Health, Denver, Colorado, United States of America.

ABSTRACT
Human rhinovirus (HRV) is the most common cause of acute exacerbations of chronic lung diseases including asthma. Impaired anti-viral IFN-λ1 production and increased HRV replication in human asthmatic airway epithelial cells may be one of the underlying mechanisms leading to asthma exacerbations. Increased autophagy has been shown in asthmatic airway epithelium, but the role of autophagy in anti-HRV response remains uncertain. Trehalose, a natural glucose disaccharide, has been recognized as an effective autophagy inducer in mammalian cells. In the current study, we used trehalose to induce autophagy in normal human primary airway epithelial cells in order to determine if autophagy directly regulates the anti-viral response against HRV. We found that trehalose-induced autophagy significantly impaired IFN-λ1 expression and increased HRV-16 load. Inhibition of autophagy via knockdown of autophagy-related gene 5 (ATG5) effectively rescued the impaired IFN-λ1 expression by trehalose and subsequently reduced HRV-16 load. Mechanistically, ATG5 protein interacted with retinoic acid-inducible gene I (RIG-I) and IFN-β promoter stimulator 1 (IPS-1), two critical molecules involved in the expression of anti-viral interferons. Our results suggest that induction of autophagy in human primary airway epithelial cells inhibits the anti-viral IFN-λ1 expression and facilitates HRV infection. Intervention of excessive autophagy in chronic lung diseases may provide a novel approach to attenuate viral infections and associated disease exacerbations.

No MeSH data available.


Related in: MedlinePlus

Knockdown of autophagy-related gene 5 (ATG5) inhibits trehalose-induced autophagy in normal human primary airway epithelial cells.Normal human tracheobronchial epithelial cells were transfected with Naito1 chimera RNAi (control siRNA) or ATG5 chimera siRNA (ATG5 siRNA). Twenty-four hours after siRNA transfection, cells were treated with medium or trehalose (TRE, 100 mM) for 48 h. ATG5 protein (A) and LC3 I and LC3 II proteins (B) were examined by Western blot analysis with GAPDH protein used as loading control. The representative Western blot picture was shown from 2 independent experiments with each being performed in triplicate wells.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4400043&req=5

pone.0124524.g004: Knockdown of autophagy-related gene 5 (ATG5) inhibits trehalose-induced autophagy in normal human primary airway epithelial cells.Normal human tracheobronchial epithelial cells were transfected with Naito1 chimera RNAi (control siRNA) or ATG5 chimera siRNA (ATG5 siRNA). Twenty-four hours after siRNA transfection, cells were treated with medium or trehalose (TRE, 100 mM) for 48 h. ATG5 protein (A) and LC3 I and LC3 II proteins (B) were examined by Western blot analysis with GAPDH protein used as loading control. The representative Western blot picture was shown from 2 independent experiments with each being performed in triplicate wells.

Mentions: To determine whether trehalose-induced autophagy contributes to the down-regulation of IFN-λ1 upon HRV-16 infection, ATG5 was knocked down by using target-specific chimera RNA interference [33–35]. Control siRNA- or ATG5 siRNA-transfected NHTE cells were infected with HRV-16 or PBS for 6 h to examine whether ATG5 knockdown alters IFN-λ1 expression and viral load. Western blot analysis confirmed ATG5 protein reduction by ATG5 siRNA in both medium- and trehalose-treated cells (Fig 4A). Intriguingly, ATG5 siRNA was shown to increase both LC3 I and LC3 II basal protein levels although an expected reduction in the ratio of LC3 II/LC3 I protein was observed compared with control siRNA (Fig 4B). Similar results were recently reported in fibroblasts transfected with conventional siRNAs against ATG5 [36]. Trehalose treatment in control siRNA-treated cells markedly increased (4-fold) the ratio of LC3 II/LC3 I protein compared with medium control. However, the conversion of LC3 I into LC3 II after trehalose treatment was decreased by 50% following ATG5 knockdown.


Trehalose-mediated autophagy impairs the anti-viral function of human primary airway epithelial cells.

Wu Q, Jiang D, Huang C, van Dyk LF, Li L, Chu HW - PLoS ONE (2015)

Knockdown of autophagy-related gene 5 (ATG5) inhibits trehalose-induced autophagy in normal human primary airway epithelial cells.Normal human tracheobronchial epithelial cells were transfected with Naito1 chimera RNAi (control siRNA) or ATG5 chimera siRNA (ATG5 siRNA). Twenty-four hours after siRNA transfection, cells were treated with medium or trehalose (TRE, 100 mM) for 48 h. ATG5 protein (A) and LC3 I and LC3 II proteins (B) were examined by Western blot analysis with GAPDH protein used as loading control. The representative Western blot picture was shown from 2 independent experiments with each being performed in triplicate wells.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400043&req=5

pone.0124524.g004: Knockdown of autophagy-related gene 5 (ATG5) inhibits trehalose-induced autophagy in normal human primary airway epithelial cells.Normal human tracheobronchial epithelial cells were transfected with Naito1 chimera RNAi (control siRNA) or ATG5 chimera siRNA (ATG5 siRNA). Twenty-four hours after siRNA transfection, cells were treated with medium or trehalose (TRE, 100 mM) for 48 h. ATG5 protein (A) and LC3 I and LC3 II proteins (B) were examined by Western blot analysis with GAPDH protein used as loading control. The representative Western blot picture was shown from 2 independent experiments with each being performed in triplicate wells.
Mentions: To determine whether trehalose-induced autophagy contributes to the down-regulation of IFN-λ1 upon HRV-16 infection, ATG5 was knocked down by using target-specific chimera RNA interference [33–35]. Control siRNA- or ATG5 siRNA-transfected NHTE cells were infected with HRV-16 or PBS for 6 h to examine whether ATG5 knockdown alters IFN-λ1 expression and viral load. Western blot analysis confirmed ATG5 protein reduction by ATG5 siRNA in both medium- and trehalose-treated cells (Fig 4A). Intriguingly, ATG5 siRNA was shown to increase both LC3 I and LC3 II basal protein levels although an expected reduction in the ratio of LC3 II/LC3 I protein was observed compared with control siRNA (Fig 4B). Similar results were recently reported in fibroblasts transfected with conventional siRNAs against ATG5 [36]. Trehalose treatment in control siRNA-treated cells markedly increased (4-fold) the ratio of LC3 II/LC3 I protein compared with medium control. However, the conversion of LC3 I into LC3 II after trehalose treatment was decreased by 50% following ATG5 knockdown.

Bottom Line: We found that trehalose-induced autophagy significantly impaired IFN-λ1 expression and increased HRV-16 load.Inhibition of autophagy via knockdown of autophagy-related gene 5 (ATG5) effectively rescued the impaired IFN-λ1 expression by trehalose and subsequently reduced HRV-16 load.Intervention of excessive autophagy in chronic lung diseases may provide a novel approach to attenuate viral infections and associated disease exacerbations.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, National Jewish Health, Denver, Colorado, United States of America.

ABSTRACT
Human rhinovirus (HRV) is the most common cause of acute exacerbations of chronic lung diseases including asthma. Impaired anti-viral IFN-λ1 production and increased HRV replication in human asthmatic airway epithelial cells may be one of the underlying mechanisms leading to asthma exacerbations. Increased autophagy has been shown in asthmatic airway epithelium, but the role of autophagy in anti-HRV response remains uncertain. Trehalose, a natural glucose disaccharide, has been recognized as an effective autophagy inducer in mammalian cells. In the current study, we used trehalose to induce autophagy in normal human primary airway epithelial cells in order to determine if autophagy directly regulates the anti-viral response against HRV. We found that trehalose-induced autophagy significantly impaired IFN-λ1 expression and increased HRV-16 load. Inhibition of autophagy via knockdown of autophagy-related gene 5 (ATG5) effectively rescued the impaired IFN-λ1 expression by trehalose and subsequently reduced HRV-16 load. Mechanistically, ATG5 protein interacted with retinoic acid-inducible gene I (RIG-I) and IFN-β promoter stimulator 1 (IPS-1), two critical molecules involved in the expression of anti-viral interferons. Our results suggest that induction of autophagy in human primary airway epithelial cells inhibits the anti-viral IFN-λ1 expression and facilitates HRV infection. Intervention of excessive autophagy in chronic lung diseases may provide a novel approach to attenuate viral infections and associated disease exacerbations.

No MeSH data available.


Related in: MedlinePlus