Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect

Introduction. Cigarette smoke (CS) exposure is the leading risk factor for COPD-emphysema pathogenesis. A common characteristic of COPD is impaired phagocytosis that causes frequent exacerbations in patients leading to increased morbidity. However, the underlying mechanism is unclear. Hence, we inve...

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Main Authors: Garrett Pehote, Manish Bodas, Kathryn Brucia, Neeraj Vij
Format: Article
Language:English
Published: Wiley 2017-01-01
Series:Mediators of Inflammation
Online Access:http://dx.doi.org/10.1155/2017/3028082
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author Garrett Pehote
Manish Bodas
Kathryn Brucia
Neeraj Vij
author_facet Garrett Pehote
Manish Bodas
Kathryn Brucia
Neeraj Vij
author_sort Garrett Pehote
collection DOAJ
description Introduction. Cigarette smoke (CS) exposure is the leading risk factor for COPD-emphysema pathogenesis. A common characteristic of COPD is impaired phagocytosis that causes frequent exacerbations in patients leading to increased morbidity. However, the underlying mechanism is unclear. Hence, we investigated if CS exposure causes autophagy impairment as a mechanism for diminished bacterial clearance via phagocytosis by utilizing murine macrophages (RAW264.7 cells) and Pseudomonas aeruginosa (PA01-GFP) as an experimental model. Methods. Briefly, RAW cells were treated with cigarette smoke extract (CSE), chloroquine (autophagy inhibitor), TFEB-shRNA, CFTR(inh)-172, and/or fisetin prior to bacterial infection for functional analysis. Results. Bacterial clearance of PA01-GFP was significantly impaired while its survival was promoted by CSE (p<0.01), autophagy inhibition (p<0.05; p<0.01), TFEB knockdown (p<0.01; p<0.001), and inhibition of CFTR function (p<0.001; p<0.01) in comparison to the control group(s) that was significantly recovered by autophagy-inducing antioxidant drug, fisetin, treatment (p<0.05; p<0.01; and p<0.001). Moreover, investigations into other pharmacological properties of fisetin show that it has significant mucolytic and bactericidal activities (p<0.01; p<0.001), which warrants further investigation. Conclusions. Our data suggests that CS-mediated autophagy impairment as a critical mechanism involved in the resulting phagocytic defect, as well as the therapeutic potential of autophagy-inducing drugs in restoring is CS-impaired phagocytosis.
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spelling doaj-art-e6efedb78a9c4a56b818a3a28055d5762025-08-20T03:26:11ZengWileyMediators of Inflammation0962-93511466-18612017-01-01201710.1155/2017/30280823028082Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis DefectGarrett Pehote0Manish Bodas1Kathryn Brucia2Neeraj Vij3College of Medicine, Central Michigan University, Mount Pleasant, MI, USACollege of Medicine, Central Michigan University, Mount Pleasant, MI, USACollege of Medicine, Central Michigan University, Mount Pleasant, MI, USACollege of Medicine, Central Michigan University, Mount Pleasant, MI, USAIntroduction. Cigarette smoke (CS) exposure is the leading risk factor for COPD-emphysema pathogenesis. A common characteristic of COPD is impaired phagocytosis that causes frequent exacerbations in patients leading to increased morbidity. However, the underlying mechanism is unclear. Hence, we investigated if CS exposure causes autophagy impairment as a mechanism for diminished bacterial clearance via phagocytosis by utilizing murine macrophages (RAW264.7 cells) and Pseudomonas aeruginosa (PA01-GFP) as an experimental model. Methods. Briefly, RAW cells were treated with cigarette smoke extract (CSE), chloroquine (autophagy inhibitor), TFEB-shRNA, CFTR(inh)-172, and/or fisetin prior to bacterial infection for functional analysis. Results. Bacterial clearance of PA01-GFP was significantly impaired while its survival was promoted by CSE (p<0.01), autophagy inhibition (p<0.05; p<0.01), TFEB knockdown (p<0.01; p<0.001), and inhibition of CFTR function (p<0.001; p<0.01) in comparison to the control group(s) that was significantly recovered by autophagy-inducing antioxidant drug, fisetin, treatment (p<0.05; p<0.01; and p<0.001). Moreover, investigations into other pharmacological properties of fisetin show that it has significant mucolytic and bactericidal activities (p<0.01; p<0.001), which warrants further investigation. Conclusions. Our data suggests that CS-mediated autophagy impairment as a critical mechanism involved in the resulting phagocytic defect, as well as the therapeutic potential of autophagy-inducing drugs in restoring is CS-impaired phagocytosis.http://dx.doi.org/10.1155/2017/3028082
spellingShingle Garrett Pehote
Manish Bodas
Kathryn Brucia
Neeraj Vij
Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect
Mediators of Inflammation
title Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect
title_full Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect
title_fullStr Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect
title_full_unstemmed Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect
title_short Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect
title_sort cigarette smoke exposure inhibits bacterial killing via tfeb mediated autophagy impairment and resulting phagocytosis defect
url http://dx.doi.org/10.1155/2017/3028082
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