title: Raman imaging of macrophages incubated with triglyceride-enriched oxLDL visualizes translocation of lipids between endocytic vesicles and lipid droplets.
abstract: Raman spectroscopic imaging was used to investigate the uptake of oxidized LDLs (oxLDLs) by human macrophages. To better understand the endocytic pathway and the intracellular fate of modified lipoproteins is of foremost interest with regard to the development of atherosclerotic plaques. To obtain information on the storage process of lipids caused by oxLDL uptake, Raman spectroscopic imaging was used because of its unique chemical specificity, especially for lipids. For the present study, a protocol was established to incorporate deuterated tripalmitate into oxLDL. Subsequently, human THP-1 macrophages were incubated for different time points and their chemical composition was analyzed using Raman spectroscopic imaging. β-Carotene was found to be a reliable marker molecule for the uptake of lipoproteins into macrophages. In addition, lipoprotein administration led to small endocytic vesicles with different concentrations of deuterated lipids within the cells. For the first time, the translocation of deuterated lipids from endocytic vesicles into lipid droplets over time is reported in mature human THP-1 macrophages.
authors.affiliation: Leibniz Institute of Photonic Technology (IPHT), 07745 Jena, Germany.|Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.
authors.forename: Clara
authors.initials: C
authors.lastname: Stiebing
authors.affiliation: Institute of Nutrition and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.|Competence Cluster of Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Friedrich Schiller University Jena, 07743 Jena, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Schmölz
authors.affiliation: Institute of Nutrition and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.|Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
authors.forename: Maria
authors.initials: M
authors.lastname: Wallert
authors.affiliation: Leibniz Institute of Photonic Technology (IPHT), 07745 Jena, Germany.|Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Matthäus
authors.affiliation: Institute of Nutrition and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.|Competence Cluster of Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Friedrich Schiller University Jena, 07743 Jena, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Lorkowski
authors.affiliation: Leibniz Institute of Photonic Technology (IPHT), 07745 Jena, Germany juergen.popp@leibniz-ipht.de.|Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Popp
mesh_terms: D001692:Biological Transport; D002460:Cell Line; D006801:Humans; D066292:Lipid Droplets / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism; D057054:Molecular Imaging; D013059:Spectrum Analysis, Raman; D022161:Transport Vesicles / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D008077:Lipoproteins, LDL; D014280:Triglycerides; C099252:oxidized low density lipoprotein
keywords: Raman spectroscopy; atherosclerosis; endocytosis; oxidized low density lipoprotein; tripalmitate; β-carotene