Endothelial handling of chromogranin A.

Abstract

ConclusionThe present study is the first to address the question of interaction between CGA and endothelial cells. It is evident that neither intact CGA nor N-terminal peptides activate endothelial cells by affecting the membrane potential. Nevertheless, bovine aorta endothelial cells (BAEC) bind and intemalise intact CGA in a temperature-dependent manner, and the binding occurs by low affinity and high capacity. BAEC do not express specific, high affinity membrane-associated binding sites for CGA. Cell surface charge appears, on the other hand, to be important for the low affinity binding, seemingly followed by non-specific adsorptive endocytosis involving plasmalemma1 vesicles. The different kinetics for CGA and inulin migration across the BAEC monolayer indicate that CGA is slowly transported by a transcellular route, consistent with transcytosis involving shuttle of vesicles between the luminal and abluminal side of the endothelial cell. Intemalised CGA may account for a pool of trapped CGA in equilibrium with circulating CGA.Taking into account the regional differences in endothelial properties and functions, the present approach to analyse CGA exchange in the macrovascular model should also be applied to endothelial cells derived from the microvasculature.