Intralipid Increases Nitric Oxide Release from Human Endothelial Cells During Oxidative Stress. JPEN J Parenter Enteral Nutr 2021 Feb;45(2):295-302
Date
04/16/2020Pubmed ID
32291784Pubmed Central ID
PMC8480443DOI
10.1002/jpen.1834Scopus ID
2-s2.0-85083448695 (requires institutional sign-in at Scopus site) 3 CitationsAbstract
BACKGROUND: Intralipid (ILP), a lipid emulsion, protects organs against ischemia/reperfusion (IR) injury. We hypothesized that ILP activates endothelial nitric oxide synthase (eNOS) and increases NO release from endothelial cells (ECs) through a fatty-acid translocase cluster of differentiation (CD36) mediated endocytotic mechanism, acting as a potentially protective paracrine signal during oxidative stress.
METHODS: Human umbilical-vein ECs were exposed to 1% ILP for 2 hours followed by oxidative stress with 0.2-mM hydrogen peroxide for 2 hours. Western blots were conducted with anti-CD36, dynamin-2, src-kinase-1, eNOS, and phospho-eNOS; equal protein loading was confirmed with β-actin. CD36 immunoprecipitation was probed for caveolin-1 to determine if CD36 and caveolin-1 were complexed on the cell membrane. NO was measured by fluorescence of ECs.
RESULTS: ILP caused a 227% increase in CD36 expression vs controls. Immunoprecipitation indicated a CD36/caveolin-1 complex on ECs' membrane with exposure to ILP. Dynamin-2 increased 52% and src-kinase-1 340% after ILP treatment vs control cells. eNOS phosphorylation was confirmed by a 63% increase in the phospho-eNOS/eNOS ratio in ILP-treated cells, and NO fluorescence increased 102%.
CONCLUSION: ILP enters ECs via endocytosis by a CD36/caveolin-1 cell membrane receptor complex, which in turn is pulled into the cell by dynamin-2 activity. Upregulation of src-kinase-1 and eNOS phosphorylation suggest downstream mediators. Subsequent NO release from ECs serve as a paracrine signal to neighboring cells for protection against IR injury. Student t-test was utilized for single comparisons and analysis of variance with Bonferroni-Dunn post hoc modification for multiple comparisons; P < .05 was considered statistically significant.
Author List
Weihrauch D, Shumpert SD, Larson ME, McVey N, Krolikowski JG, Bamkole O, Riess MLAuthor
Dorothee Weihrauch DVM, PhD Research Scientist II in the Anesthesiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Cells, CulturedEmulsions
Endothelial Cells
Humans
Nitric Oxide
Nitric Oxide Synthase Type III
Oxidative Stress
Phospholipids
Phosphorylation
Soybean Oil
