Arginine vasopressin increases aquaporin-1 expression and hydraulic conductivity in bovine aortic endothelial cell monolayers

The pressure inside large arteries is typically ~100 mmHg higher than outside of them. This difference, ¿P, drives a flow of plasma, mainly water and advected/swept-along solutes, that would otherwise only transport by (much slower) diffusion [1], across the porous vessel wall. It is natural to ask whether this flow enters the wall across the endothelium solely through inter-endothelial cell (EC) junctions or whether a portion of the water traverses the ECs via membrane proteins from the ubiquitous aquaporin (AQP) family [2]. Belkacemi et al. [3] showed a 5 fold protein expressional change of AQP1 in trophoblast cells after treatment with arginine vasopressin (AVP). We have found conditions under which AVP upregulates the hydraulic conductivity (Lp) of cultured bovine aortic ECs and upregulates their AQP1 expression in vitro. Our next step is to apply this procedure to whole rat aortas ex vivo. Specific Aim 1: Study the differences in water filtration properties of BAEC mono-layers under effects of AVP treatment to upregulate AQP1 expression. (A) Measure and compare the Lp of both treated and untreated monolayers (B) Quantify protein expression change induced by AVP treatment using immunohis-tochemistry, Western Blot and/or with Quantitative Real Time Polymerase Chain Reaction (Q-RT-PCR) (for mRNA analysis). (C) Perform solute drag experiment to investigate paracellular transport in treated vs. control BAEC monolayers.