Dietary Fatty Acids Amplify Inflammatory Responses to Infection through p38 MAPK Signaling

Dietary Fatty Acids Amplify Inflammatory Responses to Infection through p38 MAPK Signaling.

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Item Type: Article
Status: Published
Official URL:
Journal or Publication Title: American Journal of Respiratory Cell and Molecular Biology
Volume: 60
Number: 5
Page Range: pp. 554-568
Date: 2019
Divisions: UTS Centre for Inflammation
Depositing User: General Admin
Identification Number: 10.1165/rcmb.2018-0215OC
ISSN: 1044-1549
Date Deposited: 21 Dec 2020 22:42

Obesity is an important risk factor for severe asthma exacerbations, which are mainly caused by respiratory infections. Dietary fatty acids, which are increased systemically in obese patients and are further increased after high-fat meals, affect the innate immune system and may contribute to dysfunctional immune responses to respiratory infection. In this study we investigated the effects of dietary fatty acids on immune responses to respiratory infection in pulmonary fibroblasts and a bronchial epithelial cell line (BEAS-2B). Cells were challenged with BSA-conjugated fatty acids (ω-6 polyunsaturated fatty acids [PUFAs], ω-3 PUFAs, or saturated fatty acids [SFAs]) +/- the viral mimic polyinosinic:polycytidylic acid (poly[I:C]) or bacterial compound lipoteichoic acid (LTA), and release of proinflammatory cytokines was measured. In both cell types, challenge with arachidonic acid (AA) (ω-6 PUFA) and poly(I:C) or LTA led to substantially greater IL-6 and CXCL8 release than either challenge alone, demonstrating synergy. In epithelial cells, palmitic acid (SFA) combined with poly(I:C) also led to greater IL-6 release. The underlying signaling pathways of AA and poly(I:C)- or LTA-induced cytokine release were examined using specific signaling inhibitors and IB. Cytokine production in pulmonary fibroblasts was prostaglandin dependent, and synergistic upregulation occurred via p38 mitogen-activated protein kinase signaling, whereas cytokine production in bronchial epithelial cell lines was mainly mediated through JNK and p38 mitogen-activated protein kinase signaling. We confirmed these findings using rhinovirus infection, demonstrating that AA enhances rhinovirus-induced cytokine release. This study suggests that during respiratory infection, increased levels of dietary ω-6 PUFAs and SFAs may lead to more severe airway inflammation and may contribute to and/or increase the severity of asthma exacerbations.

Keywords: asthma exacerbations; dietary fatty acids; obese asthma; primary lung fibroblasts; viral infection.

Rutting, Sandra
Zakarya, Razia
Bozier, Jack
Xenaki, Dia
Horvat, Jay C.
Wood, Lisa G.
Hansbro, Philip M.
Oliver, Brian G.
Last Modified: 21 Dec 2020 22:42

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