Effects of Dietary Conjugated Linoleic Acid on Monocytes Differentiation
Ahmeed, Al Maamari Rahima Ali
Cardiff Metropolitan University
MetadataShow full item record
Conjugated linoleic acid (CLA) is a dietary polyunsaturated fatty acid. It is a mixture of positional and geometrical (cis/tran) isomers of octadecadienoic fatty acids derived from linoleic acid. CLA is naturally occurring in foods derived mainly from ruminant animals. CLA is a naturally occurring PPAR-γ ligand. PPAR-γ is the key controller of adipocyte differentiation and acts as a determinant of insulin sensitivity. PPAR-γ activation promotes differentiation of monocytes into beneficial M2 macrophages and thus, it can be hypothesized that CLA since it is PPAR-γ ligand can promote differentiation of monocytes into M2 macrophages through PPAR-γ dependent mechanisms. In this study, PMA-treated THP-1 cells were treated with 100 µM CLA alongside with 1 µM rosiglitazone (PPAR-γ agonist) and 20 ng/ml IL-13 (Th2 cytokine), which are known to promote differentiation of monocytes into M2 macrophages via PPAR-γ dependent mechanisms, and then expression of CD206 and CD163, which are M2 macrophage surface markers; were analysed using flow cytometry. It was found that CLA polarizes monocytes into M2 macrophages by inducing a significant increase of 2.3-fold in the surface expression of CD206 and 1.6-fold in the surface expression of CD163. This increase was abolished by the pre-treatment with the PPAR-γ antagonist; GW9662 which enhance the hypothesis that dietary CLA promotes polarization of monocytes into M2 macrophages via PPAR-γ activation. Moreover, CLA shows additive effect when combined with IL-13 which indicates that CLA and IL-13 act alongside to increase the polarization of moncytes into M2 macrophages and this was clearly seen by the significant increase in the surface expression of CD206 (2.8-fold) compared to CLA alone (2.3-fold) or with IL-13 alone (2.3-fold). However, this additive effect of CLA and IL-13 shows significantly lower expression of CD163 (1.4-fold) compared to when these cells were treated with CLA alone (1.6-fold) or IL-13 alone (1.6-fold) although the additive effect of CLA with IL-13shows significantly higher expression of CD163 compared to cells only. In fact, this could be due to the fact that IL-13 down regulates CD163 surface expression. Further work is required to confirm the action of CLA on PPAR-γ down to the expression of mRNA for PPAR-γ. PPAR-δ is also involved in monocytes polarization, therefore, further work is required to see its action on M2 macrophages and to use appropriate antagonist.
Showing items related by title, author, subject and abstract.
The role of conjugated linoleic acid in regulating the inflammatory response in human monocytic cells Lin, Thet Thet (Cardiff Metropolitan University, 2005)Type 2 Diabetes (T2D) is an important disorder that represents one of the most serious healthcare challenges facing the world. An estimated 293 million people worldwide are expected to have the condition by the year 2020. ...
Yakeu, Gertrude (University of WalesCardiff School of Health Sciences, 2010)Pharmacological activation of the nuclear receptor PPARγ enhances differentiation of circulating monocytes towards an alternative anti-inflammatory M2 phenotype, linked to atherosclerosis and its cardiovascular complications. ...
Yakeu, Gertrude (Cardiff Metropolitan University, 2010)Pharmacological activation of the nuclear receptor PPARγ enhances differentiation of circulating monocytes towards an alternative anti-inflammatory M2 phenotype, linked to atherosclerosis and its cardiovascular complications. ...