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Sigma‐1 receptor agonists elicit arteriolar dilation via Akt/eNOS activation, and also have endothelial barrier protective properties
Author(s) -
Motawe Zeinab Y.,
Katnik Christopher P.,
Trujillo Andrea N.,
Cuevas Javier,
Breslin Jerome W.
Publication year - 2019
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.2019.33.1_supplement.683.2
Subject(s) - enos , agonist , chemistry , protein kinase b , phosphorylation , medicine , endocrinology , umbilical vein , endothelium , receptor , endothelial dysfunction , pharmacology , microbiology and biotechnology , biology , biochemistry , nitric oxide synthase , nitric oxide , in vitro
Sigma‐1 receptors (σ1) have previously gained considerable attention pertaining to neuroprotection through its actions on calcium homeostasis, and the mitochondria‐associated ER membrane domain. Our laboratory recently showed that the σ1 agonist afobazole causes an endothelial NO‐dependent decrease in contraction amplitude. However, little is known about the mechanisms and functions of σ1 receptor in endothelial cells. In the current study, we investigated how σ1 agonists impact brain arteriolar tone and the Akt/eNOS pathway. Parenchymal arterioles were isolated from brains of Sprague‐Dawley rats and mounted onto glass micropipettes in a 37 °C bath containing albumin‐physiological salt solution. The nonselective σ agonist afobazole was applied to the bath at concentrations of 50, 100, 150, 200, and 250 μM in the presence or absence of the σ1 antagonist BD1047. The selective σ1 agonist, PRE‐084 was used to stimulate human umbilical vein endothelial cells (HUVEC), in which phosphorylation of endothelial NO synthase (eNOS) or Akt phosphorylation on their activation sites (S1177 and S473, respectively) were evaluated by western blotting. NO production was measured by fluorescence microscopy in cells loaded with the indicator dye DAF‐FM. Trans‐endothelial electrical resistance (TER) was used to determine the ability of PRE‐084 to attenuate disruption of endothelial barrier function caused by the the mitochondrial function inhibitors CCCP and antimycin‐A, or the inflammatory cytokine IL‐1β. The results show that afobazole significantly dilated rat brain arterioles, which was inhibited by the σ1 antagonist BD‐1047. Selective activation of σ1 with PRE‐084 significantly increased eNOS phosphorylation on S1177 and this was diminished in the presence of BD‐1047. Akt phosphorylation on S473 following PRE‐084 treatment was also enhanced. In addition, afobazole and PRE‐084 enhanced NO production in endothelial cells. PRE‐084 significantly attenuated decreases in TER caused by IL‐1β or CCCP, but not antimycin‐A, suggesting a potential barrier‐protective role for σ1 receptor, with some limitations that may be related to the source of mitochondrial dysfunction during inflammation. Collectively, our results suggest that σ1 receptor activation can cause vasodilation via the Akt/eNOS pathway in endothelial cells, and that σ1 may enhance endothelial barrier function under inflammatory conditions. Support or Funding Information Supported by NIH grant R01GM120774. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .