Abstract
Background: Reactive aldehydes such as acetaldehyde and malondialdehyde generated as a result of alcohol metabolism and cigarette smoke exposure lead to the formation of malondialdehyde–acetaldehyde-adducted proteins (MAA adducts). These aldehydes can adduct to different proteins such as bovine serum albumin and surfactant protein A or surfactant protein D (SPD). Macrophages play an important role in innate immunity, but the effect of MAA adducts on macrophage function has not yet been examined. Because macrophage scavenger receptor A (SRA; CD204) mediates the uptake of modified proteins, we hypothesized that the effects of MAA-modified proteins on macrophage function are primarily mediated through SRA. Methods: We tested this hypothesis by exposing SPD-MAA to macrophages and measuring functions. SPD-MAA treatment significantly stimulated pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) release in the macrophage cell line, RAW 264.7. Results: A significant reduction in phagocytosis of zymosan particles was also observed. SPD-MAA stimulated a significant dose-dependent increase in TNF-α and interleukin (IL)-6 release from peritoneal macrophages (PMs) of wild-type (WT) mice. But significantly less TNF-α and IL-6 were released from PMs of SRA−/− mice. We observed a significant reduction in phagocytosis of zymosan particles in PMs from WT mice treated with SPD-MAA. No further SPD-MAA-induced reduction was seen in PMs from SRA−/− mice. SPD-MAA treatment significantly increased SRA mRNA expression, but had no effect on surface receptor protein expression. Protein kinase C alpha inhibitor and NF-κB inhibitor significantly reduced pro-inflammatory cytokine release in response to SPD-MAA. Conclusions: In conclusion, our data demonstrate that SRA is important for MAA-adducted protein-mediated effect on macrophage functions.
Original language | English (US) |
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Pages (from-to) | 2563-2572 |
Number of pages | 10 |
Journal | Alcoholism: Clinical and Experimental Research |
Volume | 40 |
Issue number | 12 |
DOIs | |
State | Published - Dec 1 2016 |
Keywords
- Adduct
- Alcohol
- Cigarette Smoke
- Macrophage
- Scavenger Receptor A
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Toxicology
- Psychiatry and Mental health