Vitamin D Inhibits Lipopolysaccharide (LPS)-Induced Inflammation in A549 Cells by Downregulating Inflammatory Cytokines

Abstract

BACKGROUND Studies have shown that lung inflammation affects lung function, with life-threatening results. Vitamin D may play an important role in inhibiting inflammatory cytokines. Vitamin D deficiency is related to several lung problems, including respiratory distress syndrome, alveolar inflammation, epithelial damage, and hypoxia. Few studies have evaluated the benefits of vitamin D in preventing inflammation in alveolar cells. MATERIAL AND METHODS We developed a cell inflammation model induced by lipopolysaccharide (LPS) treatment. The effects of vitamin D on LPS-induced inflammation in A549 cells were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the anti-inflammatory mechanism of vitamin D was evaluated using western blot analysis. RESULTS Our results indicated that vitamin D promoted A549 cell survival following LPS-induced inflammation by downregulating nuclear factor nuclear factor kappa light chain enhancer of activated B cells, tumor necrosis factor-alpha, interleukin (IL)-1ß, IL-6, and IL-12. CONCLUSIONS Our results indicated that vitamin D has the potential to manage lung inflammation, although further studies are needed.

Figure 1

Vitamin D inhibits LPS-induced cytotoxicity in A549 cells. The data are presented as the mean±SD error bars of the mean (n=3). * P<0.05 vs LPS. Vit D – vitamin D; LPS – lipopolysaccharide.

Figure 2

Vitamin D decreased lipopolysaccharide (LPS)-induced inflammatory cytokine expression. A549 cells were treated with 1 μM, 0.1 μM, and 0.01 μM of vitamin D with and without 30 μM of LPS for 6 h and 12 h. (A, B) Relative protein levels of NF-κB; (C, D) IL-1β; (E, F) IL-6; (G, H) IL-12; and (I, J) TNF-α. (K, L) Expression of all proteins as measured using western blot with an internal control (GAPDH). Data are shown as mean±SD and * P<0.05 indicates a significant difference relative to LPS treatment. Vit D – vitamin D; LPS – lipopolysaccharide; GADPH – glyceraldehyde-3-phosphate dehydrogenase; NF – nuclear factor kappa light chain enhancer of activated B cells; IL – interleukin; TNF – tumor necrosis factor.