Somatostatin regulates intracellular signaling pathways in human coronary artery endothelial cells
Biochemical and Biophysical Research Communications, 319, 1222- 1227, July 2004
Allan D. Blake, Ph.D.
Department of Biological Sciences
A.C. Badway, F.M. West and S.M. Tente
Somatostatin (somatotropin release inhibitory factor; SRIF) is an endogenous peptide produced at sites of inflammation, making the SRIF a candidate in regulating vascular inflammation. We have used primary human coronary artery endothelial cells (hCAEC) as a model to study SRIF’s vascular actions. RT-PCR analysis of hCAEC total mRNA demonstrated the presence of the sst4 receptor subtype, providing a target for SRIF intracellular signaling. Western blotting with phospho-specific ERK1/2 antibodies showed that SRIF-14 acutely inhibited basal phosphorylation of the extracellular regulated kinases (ERK1/2) by 80%. In addition, SRIF-14 treated hCAEC cell lysates showed a 2.6-fold increase in phosphatase activity, which was inhibited by sodium vanadate. Furthermore, SRIF-14 appeared to be anti-inflammatory in hCAEC as IL-1b-induced adhesion molecule expression was reduced by 50%. Together, these results show that the coronary artery endothelium is a direct target of SRIF action.