Mixed exposure to bacterial lipopolysaccharide and seafood proteases augments inflammatory signalling in an airway epithelial cell model (A549).

Seafood industry workers exhibit increased prevalence of respiratory symptoms due to exposure to bioaerosols containing a mixture of bioactive agents. In this study, a human pulmonary epithelial cell model (A549) was exposed to mixtures of bacterial lipopolysaccharide (LPS) and protease-activated receptor-2 (PAR-2) agonists H-Ser-Leu-Ile-Gly-Lys-Val-NH2 (SLIGKV-NH2), purified salmon ( Salmo salar) trypsin or purified king crab ( Paralithodes camtschaticus) trypsin. The inflammatory response was measured based on nuclear factor-kappa B (NF-κB) activation of transcription in a luciferase reporter gene assay and interleukin 8 (IL-8) secretion in an enzyme-linked immunosorbent assay. We observed that mixtures of SLIGKV-NH2 or trypsins with LPS augmented the activation of NF-κB and secretion of IL-8. The effect on IL-8 secretion was synergistic when both trypsins and LPS were used in the lower concentration range. The results demonstrate that exposure to mixtures of agents that are relevant to seafood industry workplaces may lead to increased inflammatory signalling compared with exposure to the individual agents alone. Furthermore, the results indicate that synergism may occur with the combined exposure to seafood trypsins and LPS and is most likely to occur when exposure to either agent is low.

Salmon and king crab trypsin stimulate interleukin-8 and matrix metalloproteinases via protease-activated receptor-2 in the skin keratinocytic HaCaT cell line.

Occupational skin symptoms are prevalent among the workers of the seafood processing industry. In this study we investigate the role of salmon (Salmo salar) and king crab trypsin (Paralithodes camtschaticus) as inducers of inflammation in skin via secretion of inflammatory mediators. Human skin keratinocytes (HaCaT cells) were exposed to purified salmon and king crab trypsin. We observed that salmon trypsin enhanced the secretion of IL-8 and MMP-2 and crab trypsin enhanced the secretion of IL-8, MMP-2 and MMP-9 in a dose dependent manner. As protease activated receptors (PAR)-2 in skin are known to play an important role in physiology and pathology, we explored the involvement of these receptors in mediating the release of interleukin (IL)-8 and matrix metalloproteinase (MMP)-2 and -9 subsequent to exposure of skin keratinocytes to salmon and crab trypsin. In addition we observed that salmon and crab trypsin exhibit individual differences in stimulating the release of these inflammatory mediators. Finally, using specific small interfering RNA (siRNA) against PAR-2, we confirmed that the increase in secretion of IL-8, MMP-2 and MMP-9 in skin keratinocytes following exposure to salmon and crab trypsin was mediated via activation of PAR-2. These results suggest that exposure to proteases from the seafood may lead to inflammatory reactions in skin.