Somatostatin Primes Endothelial Cells for Agonist-Induced Hyperpermeability and Angiogenesis In Vitro

• Published in: International journal of molecular sciences Vol. 23; no. 6; p. 3098
• Main Authors: Aslam, Muhammad, Idrees, Hafiza, Ferdinandy, Peter, Helyes, Zsuzsanna, Hamm, Christian, Schulz, Rainer
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.03.2022; MDPI
• Subjects: 1-Phosphatidylinositol 3-kinase; Akt; AKT protein; Angiogenesis; Cell proliferation; Cells, Cultured; Endothelial cells; endothelial permeability; Extracellular signal-regulated kinase; Growth factors; Hormones; Human Umbilical Vein Endothelial Cells - metabolism; Humans; Kinases; MAP kinase; MAPK; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase Kinases - metabolism; Neovascularization, Pathologic - metabolism; Neurotransmission; Permeability; Phosphorylation; Proteins; Proto-Oncogene Proteins c-akt - metabolism; RhoA/Rock; Signal transduction; Smooth muscle; Somatostatin; Somatostatin - metabolism; Somatostatin - pharmacology; somatostatin receptors; Thrombin; Thrombin - metabolism; Thrombin - pharmacology; Tumors; Umbilical vein; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - metabolism; Vascular system; angiogenesis; MYPT1; somatostatin receptors; Akt; MAPK; cAMP; RhoA/Rock; endothelial permeability
• DOI: 10.3390/ijms23063098
• ISSN: 1422-0067; 1661-6596

Somatostatin is an inhibitory peptide, which regulates the release of several hormones, and affects neurotransmission and cell proliferation via its five G protein-coupled receptors (SST ). Although its endocrine regulatory and anti-tumour effects have been thoroughly studied, little is known about its effect on the vascular system. The aim of the present study was to analyse the effects and potential mechanisms of somatostatin on endothelial barrier function. Cultured human umbilical vein endothelial cells (HUVECs) express mainly SST and SST receptors. Somatostatin did not affect the basal HUVEC permeability, but primed HUVEC monolayers for thrombin-induced hyperpermeability. Western blot data demonstrated that somatostatin activated the phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt) and p42/44 mitogen-activated protein kinase (MAPK) pathways by phosphorylation. The HUVEC barrier destabilizing effects were abrogated by pre-treating HUVECs with mitogen-activated protein kinase kinase/extracellular signal regulated kinase (MEK/ERK), but not the Akt inhibitor. Moreover, somatostatin pre-treatment amplified vascular endothelial growth factor (VEGF)-induced angiogenesis (3D spheroid formation) in HUVECs. In conclusion, the data demonstrate that HUVECs under quiescence conditions express SST and SST receptors. Moreover, somatostatin primes HUVECs for thrombin-induced hyperpermeability mainly via the activation of MEK/ERK signalling and promotes HUVEC proliferation and angiogenesis in vitro.