Abstract 132: Proteomic Profiles Of Human Arterioles Isolated From Fresh Adipose Tissue Or Following Overnight Storage

Abstract

Resistance arteries, or arterioles, are key determinants of the total peripheral vascular resistance, which, in turn, is a key determinant of arterial blood pressure (BP). However, the amount of protein available from one isolated human arteriole may be less than 5 μg, making proteomic analysis challenging. In addition, obtaining human arterioles requires manual dissection of unfrozen clinical specimens. This limits its feasibility, especially for powerful multi-center clinical studies in which clinical specimens need to be shipped overnight to a research lab for arteriole isolation. We performed a study to address low input, test overnight tissue storage, and develop a reference human arteriolar proteomic profile. We found that, in tandem mass tag proteomic analysis, the use of a booster channel consisting of endothelial and vascular smooth muscle cells (1:5 ratio) increased the number of proteins detected in a human arteriole segment with FDR < 0.01 from 1,051 to more than 3,000. We collected adipose tissues from three human subjects and isolated two arterioles from each fresh aliquot of the tissue or after 24h of cold storage of unfrozen aliquots in MACS tissue solution. The correlation coefficient of proteomic profile was similar (p=0.6) between replicate arterioles isolated freshly, following the cold storage, or before and after the cold storage. We built a human arteriolar proteomic profile consisting of 3,836 proteins based on the analysis of 12 arteriole samples from the three subjects. The average arteriolar protein had a mean copy number of 2.76х10 6 per cell using the histone proteomic ruler, which is based on the fact that the mass of DNA per cell is approximately equal to the protein mass of histones. Transgelin was the most abundant protein detected. We curated a set of BP-relevant human genes, which encode 1,945 proteins. Of these BP-relevant proteins, 476 (12.5%) were detected in the arteriolar proteome, which was a significant overrepresentation (p<0.05, Chi squared test). These findings demonstrate that proteomic analysis is feasible with arterioles isolated from human adipose tissue following cold overnight storage and provide a reference human arteriolar proteome profile highly valuable for studies of arteriole-related traits.