Non‐genomic mechanisms in the estrogen regulation of glycolytic protein levels in endothelial cells

Abstract

Few studies have explored the mechanisms coupling estrogen signals to metabolic demand in endothelial cells. We recently showed that 17β‐estradiol (E2) triggers angiogenesis via the membrane G‐protein coupled estrogen receptor (GPER) and the key glycolytic protein PFKFB3 as a downstream effector. We herein investigated whether estrogenic agents regulate the stability and/or degradation of glycolytic proteins in human umbilical vein endothelial cells (HUVECs). Similarly to E2, the GPER selective agonist G1 rapidly increased PFKFB3 protein amounts, without affecting mRNA levels. In the presence of cycloheximide, E2 and G1 treatment counteracted PFKFB3 degradation over time, whereas E2‐induced PFKFB3 stabilization was abolished by the GPER antagonist G15. Inhibitors of selective SCF E3 ubiquitin ligase (SMER‐3) and proteasome (MG132) rapidly increased PFKFB3 protein levels. Accordingly, ubiquitin‐bound PFKFB3 was lower in E2‐ or G1‐treated HUVECs. Both agents increased deubiquitinase USP19 levels through GPER signaling. Notably, USP 19 siRNA decreased PFKFB3 levels and abolished E2‐ and G1‐mediated HUVEC tubularization. Finally, E2 and G1 treatments rapidly enhanced glucose transporter GLUT1 levels via GPER independent of transcriptional activation. These findings provide new evidence on mechanisms coupling estrogen signals with the glycolytic program in endothelium and unravel the role of USP19 as a target of the pro‐angiogenic effect of estrogenic agents.

Estrogens and the regulation of glucose metabolism

“…E2 lowers liver glucose output with no changes in glycogen during mild exercise[ 268 ], a difference due in part to a modulable maintenance/ inhibition of gluconeogenesis[ 269 ]. E2 also regulates glycolysis in endothelial cells by non-genomic pathways[ 270 ], partly by increasing insulin signaling[ 271 ]. Glucose catabolism is affected by estrogens, which stimulate glycolysis via phosphofructokinase[ 272 ], and the pentose phosphate pathway via Akt[ 273 ].…”

Estrogen Receptor Functions and Pathways at the Vascular Immune Interface

“…This involves a novel mechanism of estrogenic regulation of PFKFB3 mediated by GPER. E2 and G1 also increase endothelial GLUT1 protein expression via GPER through different mechanisms [45,46]. These findings suggest that ERs represent potential targets to afford selective modulation of endothelial function and angiogenesis.…”

“…Similarly, endothelial cells are essential in regulating HSCs in the perivascular niche [94], but the possible effects of E2 on bone marrow endothelial cells are still unknown. Indeed, E2 can modulate endothelial cell metabolism through GPER [45,46] and this effect could be exploited to modulate the endothelial cell-HSC cross-talk [107], restrain myelopoiesis and ultimately improve cardiovascular health.…”

Nuclear and Membrane Receptors for Sex Steroids Are Involved in the Regulation of Delta/Serrate/LAG-2 Proteins in Rodent Sertoli Cells

“…Of note, GPER silencing in TM4 cells produced significant change in DLL4 expression only at the protein level, which suggests that activity of nonclassical estrogen signaling may be involved in the post-translational regulation of DLL4. Recently, the role of GPER independent of transcriptional activation was reported in the regulation of endothelial glucose transporter 1 [63].…”