Oleacein and Foam Cell Formation in Human Monocyte-Derived Macrophages: A Potential Strategy Against Early and Advanced Atherosclerotic Lesions

Agnieszka Filipek; Tomasz P Mikołajczyk; Tomasz J Guzik; Marek Naruszewicz

doi:10.3390/ph13040064

Oleacein and Foam Cell Formation in Human Monocyte-Derived Macrophages: A Potential Strategy Against Early and Advanced Atherosclerotic Lesions

Pharmaceuticals (Basel). 2020 Apr 9;13(4):64. doi: 10.3390/ph13040064.

Authors

Agnieszka Filipek¹, Tomasz P Mikołajczyk^{2

3}, Tomasz J Guzik^{3

4}, Marek Naruszewicz¹

Affiliations

¹ Department of Pharmacognosy and Molecular Basis of Phytotherapy, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland.
² Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building 120 University Place, Glasgow G12 8TA, UK.
³ Department of Internal and Agricultural Medicine, Jagiellonian University Medical College, 31-007 Krakow, Poland.
⁴ Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF Centre for Excellence, 120 University Place, Glasgow G12 8TA, UK.

Abstract

Background: Oleacein is a secoiridoid group polyphenol found mostly in Olea europea L. and Ligustrum vulgare L. (Oleaceae). The aim of the present study was to investigate a potential role of oleacein in prevention of the foam cell formation.

Materials and methods: Oleacein was isolated from Ligustrum vulgare leaves. Human monocyte-derived macrophages were obtained from monocytes cultured with Granulocyte-macrophage colony-stimulating factor (GM-CSF)Then, cells were incubated with 20 M or 50 M of oleacein and with oxidized low-density lipoprotein (oxLDL) (50 g/mL). Visualization of lipid deposition within macrophages was carried out using Oil-Red-O. Expression of CD36, Scavenger receptor A1 (SRA1) and Lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) was determined by Reverse transcription polymerase chain reaction (RT-PCR) and by flow cytometry. Apoptosis was determined by flow cytometry using Annexin V assay. STAT3 and Acyl-coenzyme A:cholesterol acyltransferase type 1 (ACAT1)levels were determined by ELISA. P-STAT3, P-JAK1, P-JAK2 expressions were determined by Western blot (WB).

Results: Oleacein in dose-dependent manner significantly reduced lipid deposits in macrophages as well as their expression of selected scavenger receptors. The highest decrease of expression was found for CD36 and SRA1 receptors, from above 20% to more than 75% compared to oxLDL and the lowest for LOX-1 receptor, from approx. 8% to approx. 25% compared to oxLDL-stimulated macrophages. Oleacein significantly reduced (2.5-fold) early apoptosis of oxLDL-stimulated macrophages. Moreover, oleacein significantly increased the protein expression of JAK/STAT3 pathway and had no effect on ACAT1 level.

Conclusions: Our study demonstrates, for the first time, that oleacein inhibits foam cell formation in human monocyte-derived macrophages and thus can be a valuable tool in the prevention of early and advanced atherosclerotic lesions.

Keywords: JAK/STAT3 pathway; atherosclerosis; foam cell formation; human monocyte-derived macrophages (hMDMs); oleacein; scavenger receptors (SR).