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Differential growth state‐dependent activation of p38MAPK by treatment of endothelial cells with docosahexaenoic acid (DHA)
Author(s) -
Du Youjia,
Taylor Carla G,
Aukema Harold M,
Zahradka Peter
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.946.2
Subject(s) - docosahexaenoic acid , microbiology and biotechnology , protein kinase a , endothelial stem cell , matrigel , cell growth , endothelium , biology , cell culture , kinase , cell , biochemistry , fatty acid , endocrinology , in vitro , polyunsaturated fatty acid , genetics
Endothelial cells line the luminal surface of blood vessels and play an essential role in regulating vascular function. Endothelial cells quiescence is a primary property of the healthy endothelium, whereas cell proliferation is feature of vessel repair and progression of atherosclerosis. Docosahexaenoic acid (DHA), an omega‐3 fatty acid present in fish oil, is thought to exert an array of beneficial effects on vascular health by modulating endothelial function. However, a comparison of the effects of DHA on growing and confluent endothelial cells, which represent repairing and healthy states, respectively, has never been reported. Objective To investigate the effects of DHA on viability and proliferation of subconfluent (growing) and confluent (quiescent) human endothelial cells (EA.hy926) in relation to p38 mitogen‐activated protein kinase (MAPK) activation. Methods EA.hy926 endothelial cells were seeded on Matrigel‐coated plates and grown up to 10 days. Cells were treated with DHA (1–150 μM) for 24 h when they were either subconfluent (4 d after seeding) or confluent (8 d after seeding). Viability and proliferation were assessed. Phosphorylation of p38MAPK and mitogen‐activated protein kinase kinase (MKK3/MKK6) was assessed after treating subconfluent and confluent cells with 125 μM DHA over 8 h. Results Maximum cell number and DNA synthesis rate were reached on day 8, and the cells subsequently became quiescent. DHA >125 μM reduced viability of both growing and confluent cells after 24 h, while 40 μM slowed proliferation of both subconfluent and confluent cells. In subconfluent cells, 125 μM DHA activated p38MAPK and MKK3/MKK6 (a known upstream kinase), producing peaks at both 10 min and 4 h. In contrast, phospho‐p38MAPK and phospho‐MKK3/MKK6 peaks were only observed at 10 min in confluent cells. Conclusions Our study is the first to show a dose‐dependent effect of DHA on both proliferating and confluent endothelial cells with regards to viability and proliferation, as well as a growth state‐dependent activation of p38MAPK. This is highly relevant to how blood vessels respond to a dietary constituent such as DHA in various disease states. Since activation of stress‐stimulated protein p38MAPK, which is closely linked to pathological vascular remodeling, was observed in different growth conditions of cells, further studies to delineate the physiological effects of DHA on p38MAPK signal transduction in endothelial cells are warranted.