Abstracts

#59 Αlpha-Linolenic acid alters the production of oxylipins and pro-inflammatory cytokines in classically activated THP-1 macrophages


Lisa Rodway, University of Manitoba, Canadian Centre for Agri-Food Research in Health and Medicine; Samantha Pauls, University of Manitoba, Canadian Centre for Agri-Food Research in Health and Medicine; Harold Aukema, University of Manitoba, Canadian Centre for Agri-Food Research in Health and Medicine; Peter Zahradka, University of Manitoba, Canadian Centre for Agri-Food Research in Health and Medicine; Carla Taylor, University of Manitoba, Canadian Centre for Agri-Food Research in Health and Medicine


Introduction

The prevalence of type 2 diabetes (T2D) in children and adolescents is increasing in Canada, which comes with great personal and societal cost. T2D is recognized as a chronic pro-inflammatory disease, as dysregulated immune cells such as macrophages are directly implicated in its pathogenesis. Bioactive dietary omega-3 fats such as alpha-linolenic acid (ALA) have anti-inflammatory properties and therefore might be employed as part of a dietary strategy for prevention and/or management of T2D. However, the mechanism(s) by which ALA carries out these effects is not yet clear. ALA and other polyunsaturated fatty acids (PUFAs) are converted to a series of oxygenated metabolites, known as oxylipins. Some oxylipins, especially those derived from the omega-3 PUFA docosahexaenoic acid (DHA), possess direct anti-inflammatory properties, while others, especially those derived from the omega-6 PUFA arachidonic acid (AA), are pro-inflammatory. We hypothesize that treatment of macrophages with ALA will increase secretion of oxylipins derived from ALA and decrease secretion of oxylipins derived from AA.


Methods

In this study, classically activated (M1-like) macrophages derived from the THP-1 human cell line were treated with ALA during their activation period and then stimulated with lipopolysaccharide (LPS). Cell supernatants were harvested for solid phase extraction of oxylipins followed by quantification using HPLC-MS/MS.


Results

Compared to oleic acid or vehicle treated controls, ALA treatment led to increases in several ALA oxylipins (9-HOTrE, 13-HOTrE, 9-oxoOTrE) and decreases in multiple AA oxylipins (e.g.12-HETE, LTB4), either in resting or LPS-stimulated cells. Additionally, a potently anti-inflammatory DHA oxylipin (16,17-EpDPE) was increased. Consistent with previous studies, ALA treatment also led to a decrease in pro-inflammatory cytokine production.


Conclusion

Future work will focus on directly linking oxylipin production to the cytokine-lowering effect of ALA. A better understanding of how lipid mediators modulate the inflammatory process may help determine the key factors underlying the progression of diabetes and its complications.