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Pennington ER, Virk R, Bridges MD, Bathon BE, Beatty N, Gray RS, Kelley P, Wassall SR, Manke J, Armstrong M, Reisdorph N, Vanduinen R, Fenton JI, Gowdy KM, Shaikh SR. Docosahexaenoic Acid Controls Pulmonary Macrophage Lipid Raft Size and Inflammation. J Nutr 2024:S0022-3166(24)00174-3. [PMID: 38582385 DOI: 10.1016/j.tjnut.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/27/2024] [Accepted: 04/02/2024] [Indexed: 04/08/2024] Open
Abstract
BACKGROUND Docosahexaenoic acid (DHA) controls the biophysical organization of plasma membrane sphingolipid/cholesterol-enriched lipid rafts to exert anti-inflammatory effects, particularly in lymphocytes. However, the impact of DHA on the spatial arrangement of alveolar macrophage lipid rafts and inflammation is unknown. OBJECTIVES The primary objective was to determine how DHA controls lipid raft organization and function of alveolar macrophages. As proof-of-concept, we also investigated DHA's anti-inflammatory effects on select pulmonary inflammatory markers with a murine influenza model. METHODS MH-S cells, an alveolar macrophage line, were treated with 50 μM DHA or vehicle control and were used to study plasma membrane molecular organization with fluorescence-based methods. Biomimetic membranes and coarse grain molecular dynamic (MD) simulations were employed to investigate how DHA mechanistically controls lipid raft size. qRT-PCR, mass spectrometry, and ELISAs were used to quantify downstream inflammatory signaling transcripts, oxylipins, and cytokines, respectively. Lungs from DHA-fed influenza-infected mice were analyzed for specific inflammatory markers. RESULTS DHA increased the size of lipid rafts while decreasing the molecular packing of the MH-S plasma membrane. Adding a DHA-containing phospholipid to a biomimetic lipid raft-containing membrane led to condensing, which was reversed with the removal of cholesterol. MD simulations revealed DHA nucleated lipid rafts by driving cholesterol and sphingomyelin into rafts. Downstream of the plasma membrane, DHA lowered the concentration of select inflammatory transcripts, oxylipins, and IL-6 secretion. DHA lowered pulmonary Il6 and Tnf-α mRNA expression and increased anti-inflammatory oxylipins of influenza-infected mice. CONCLUSIONS The data suggest a model in which the localization of DHA acyl chains to nonrafts is driving sphingomyelin and cholesterol molecules into larger lipid rafts, which may serve as a trigger to impede signaling and lower inflammation. These findings also identify alveolar macrophages as a target of DHA and underscore the anti-inflammatory properties of DHA for lung inflammation.
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Affiliation(s)
- Edward Ross Pennington
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Rafia Virk
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Meagan D Bridges
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Brooke E Bathon
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Nari Beatty
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Rosemary S Gray
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Patrick Kelley
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Stephen R Wassall
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Jonathan Manke
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Michael Armstrong
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Nichole Reisdorph
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Rachel Vanduinen
- Department of Food Science and Human Nutrition, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, United States
| | - Jenifer I Fenton
- Department of Food Science and Human Nutrition, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, United States
| | - Kymberly M Gowdy
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, the Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Saame Raza Shaikh
- Department of Nutrition, Gillings School of Global Public Health & School of Medicine, University of North Carolina at Chapel Hill, NC, United States.
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