Isoflurane Protects Against Human Endothelial Cell Apoptosis by Inducing Sphingosine Kinase-1 via ERK MAPK

Adnan M. Bakar,Mihwa Kim,H. Thomas Lee,Sang Won Park

doi:10.3390/ijms13010977

Adnan M. Bakar, Mihwa Kim + Show 2 more

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https://doi.org/10.3390/ijms13010977

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Abstract

Endothelial dysfunction is a major clinical problem affecting virtually every patient requiring critical care. Volatile anesthetics are frequently used during the perioperative period and protect the heart and kidney against ischemia and reperfusion injury. We aimed to determine whether isoflurane, the most commonly used volatile anesthetic in the USA, protects against endothelial apoptosis and necrosis and the mechanisms involved in this protection. Human endothelial EA.hy926 cells were pretreated with isoflurane or carrier gas (95% room air + 5% CO2) then subjected to apoptosis with tumor necrosis factor-α or to necrosis with hydrogen peroxide. DNA laddering and in situ Terminal Deoxynucleotidyl Transferase Biotin-dUTP Nick-End Labeling (TUNEL) staining determined EA.hy926 cell apoptosis and percent LDH released determined necrosis. We also determined whether isoflurane modulates the expression and activity of sphingosine kinase-1 (SK1) and induces the phosphorylation of extracellular signal regulated kinase (ERK MAPK) as both enzymes are known to protect against cell death. Isoflurane pretreatment significantly decreased apoptosis in EA.hy926 cells as evidenced by reduced TUNEL staining and DNA laddering without affecting necrosis. Mechanistically, isoflurane induces the phosphorylation of ERK MAPK and increased SK1 expression and activity in EA.hy926 cells. Finally, selective blockade of SK1 (with SKI-II) or S1P1 receptor (with W146) abolished the anti-apoptotic effects of isoflurane. Taken together, we demonstrate that isoflurane, in addition to its potent analgesic and anesthetic properties, protects against endothelial apoptosis most likely via SK1 and ERK MAPK activation. Our findings have significant clinical implication for protection of endothelial cells during the perioperative period and patients requiring critical care.

Highlights

The integrity and viability of the vascular endothelium are essential for homeostasis of all vital organs
Isoflurane Pretreatment Reduces Apoptosis in EA.hy926 Cells Exposed to Tumor Necrosis Factor-α (TNF-α)
Human endothelial EA.hy926 cells exposed to carrier gas for 16 hours did not display any appreciable Transferase Biotin-dUTP Nick-End Labeling (TUNEL) staining (Figure 1A and 1E)

Summary

Introduction

The integrity and viability of the vascular endothelium are essential for homeostasis of all vital organs. Endothelial cells produce several critically important compounds including nitric oxide, sphingosine 1-phosphate (S1P) and prostaglandins, which regulate blood supply and produce cytoprotection in many disease states including systemic inflammatory response syndrome and ischemia and reperfusion [1,2]. Endothelial cell dysfunction plays a major role in many acute and chronic human diseases including ischemia and reperfusion injury, coronary artery disease, diabetes mellitus and systemic inflammatory response syndrome [1,3]. Volatile anesthetics are administered to virtually all patients subjected to general anesthesia and are an integral part of the perioperative period. We previously reported that volatile anesthetics protected against renal ischemia reperfusion injury in vivo and had direct anti-inflammatory and anti-necrotic effects in cultured human kidney proximal tubule (HK-2) cells in vitro [5]. The initial anti-inflammatory mechanisms involve plasma membrane phosphatidylserine externalization with subsequent release of a potent anti-inflammatory cytokine

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