講演情報
[19a-A602-1][JSAP-Optica Joint Symposia 2023 Invited Talk] Label-free Raman imaging of saturated and unsaturated fatty acid uptake, storage, and return toward baseline levels in macrophages.
〇Alison Jane Hobro1, Takeshi Sugiyama1, Nicolas Pavillon1, Takayuki Umakoshi1, Prabhat Verma1, Nicholas Smith1 (1.Osaka Univ)
キーワード：
Raman Imaging
Lipids play many important roles in the body including cell signaling and energy storage. The presence of excessive lipids, or disruption of normal lipid metabolic processes in the cell, has been linked to lifestyle diseases such as atherosclerosis and obesity. Where the affected cells are part of the innate immune system such dysregulation of lipids has also been implicated in impaired immune responses to infection. Therefore, understanding how macrophages are affected by the presence of fatty acids in their local environment is an important step in understanding lifestyle disease development. Using Raman spectroscopic imaging we studied the uptake of several concentrations of palmitic, stearic, oleic and linoleic acid in live macrophage cells. Macrophages readily take up these lipids, which can be observed by Raman imaging at the edge of the cytoplasm close to the cell membrane, with the exact distribution dependent on the nature of the fatty acid (unsaturated/saturated) and the exposure concentration. At the highest concentrations, all fatty acids appear to be toxic to the macrophage cells after 24 hours of exposure. By comparing the Raman intensities of the pure fatty acids and ratiometric imaging of the intensities within the macrophage cells we were able to determine that the toxicity of a fatty acid is not due directly to the amount of fatty acid present in the macrophage, rather the nature of the fatty acid is important. This demonstrates the power of high-resolution ratiometric Raman imaging for bioanalysis. In addition, we monitored macrophage cells after removing fatty acids from the surrounding environment, observing a reduction in fatty acid content of the cells over the following 48 hours, showing that even heavily lipid-laden macrophages can process these excess lipids once fatty acids are removed from the environment.