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Investigation of Sphingosine‐1‐Phosphate‐induced Vasodilation in the Human Microvasculature
Author(s) -
Katunaric Boran,
Schulz Mary,
Freed Julie
Publication year - 2021
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.2021.35.s1.03061
Subject(s) - nitric oxide , s1pr1 , vasodilation , chemistry , nadph oxidase , antagonist , nitric oxide synthase , apocynin , superoxide , pharmacology , endocrinology , biochemistry , medicine , receptor , reactive oxygen species , biology , enzyme , organic chemistry , vascular endothelial growth factor a , vascular endothelial growth factor , vegf receptors
The sphingolipid sphingosine‐1‐phosphate (S1P) has emerged as a regulator of microvascular tone in animals, however its role in the human microcirculation remains unknown. Pre‐clinical studies suggest that S1P‐induced activation of two endothelial‐specific receptors, S1PR 1 and S1PR 3 ,elicits nitric‐oxide (NO)‐mediated vasodilation. As opposed to S1PR 1 , the S1PR 3 pathway also activates NADPH oxidase (NOX) to produce reactive oxygen species (ROS). We therefore hypothesized that S1P induces vasodilation in the human microvasculature through activation of S1PR 1 and S1PR 3 in both a ROS‐independent and ROS‐dependent manner, respectively. Human microvessels (100‐200µm in diameter) were prepared for videomicroscopy. Following equilibration, arterioles were pre‐constricted with endothelin‐1 to 30‐70% of their passive diameters. Luminal diameter was measured and recorded in regular intervals (1 min) in response to increasing concentrations of S1P (10 ‐12 to 10 ‐6 M) in the presence or absence of the S1PR 1 receptor antagonist W146 (10 ‐5 M), S1PR 3 antagonist CAY10444 (10 ‐5 M), nitric oxide synthase inhibitor N ω ‐nitro‐ʟ‐arginine (L‐NAME, 10 ‐4 M), NO scavenger 2‐4‐carboxyphenyl‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide (c‐PTIO, 10 ‐4 M), polyethylene glycol‐catalase (peg‐Cat, 500U/ml), NADPH oxidase inhibitor apocynin (3x10 ‐4 M), NOX‐2 inhibitor GSK2795039 (10 ‐6 M) or the NOX‐4 inhibitor GKT137831 (10 −6 M). S1P induced vasodilation in a dose‐responsive manner with a maximum dilation of 56.5%±4.9, n=12 (mean±SEM). Dilation was abolished during inhibition of S1PR 1 (1.5%±5.2, n=4) and was reduced during inhibition of S1PR 3 (19.7%±8.7, n=6). Both L‐NAME and c‐PTIO inhibited S1P‐induced dilation (13.0%±7.5, n=4 and 11.2%±3.3, n=4, respectively). Interestingly, dilation was nearly completely inhibited by peg‐Cat (11%±6.6, n=4), apocynin (12.5%±4.4, n=3) and the NOX‐4 inhibitor (7.2%±3.1, n=4). Dilation was also partly reduced during inhibition of NOX‐2 (25.6%±7.8, n=4). These data suggest that S1P‐induced dilation occurs through activation of S1PR 1 and S1PR 3 through formation of NO and NOX‐4‐generated H 2 O 2 . These translational studies highlight the inter‐species variation observed in vascular signaling and provide insight into the mechanism by which S1P regulates microvascular resistance in humans.