Unsaturated lipid bodies as a hallmark of inflammation studied by Raman 2D and 3D microscopy

• Published in: Scientific reports 2017-01, Vol.7 (1), p.40889-40889, Article 40889
• Main Authors: Czamara, K., Majzner, K., Selmi, A., Baranska, M., Ozaki, Y., Kaczor, A.
• Format: Article
• Language: English
• Subjects: 14/19; 140/133; 639/638/11/942; 639/638/45/287; Cytoplasm; Esters; Humanities and Social Sciences; Inflammation; Lecithin; Lipid bodies; Lipids; multidisciplinary; Phosphatidylcholine; Science; Science (multidisciplinary); Statistical analysis; Tumor necrosis factor
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep40889

Endothelial HMEC-1 cells incubated with pro-inflammatory cytokine TNF-α for 6 and 24 hours were studied as a model of inflammation using Raman imaging. Striking changes in distribution, composition and concentration of cellular lipids were observed after exposure to TNF-α compared to the control. In particular, 3D Raman imaging revealed a significant increase in the amount of lipid entities formed under inflammation. Lipid bodies were randomly distributed in the cytoplasm and two types of droplets were assembled: more saturated one, in spectral characteristics resembling phosphatidylcholine and saturated cholesteryl esters, observed also in the control, and highly unsaturated one, containing also cholesterols, being a hallmark of inflamed cells. The statistical analysis showed that the number of lipid bodies was significantly dependent on the exposure time to TNF-α. Overall, observed formation of unsaturated lipid droplets can be directly correlated with the increase in production of prostacyclins - endogenous inflammation mediators.