Effects of Aging on Proteome Dynamics in Mice Brain Microvessels: ROS Scavengers, mRNA/Protein Stability, Glycolytic Enzymes, Mitochondrial Complexes, and Basement Membrane Components.

R1918 --> 710.1 --> Background: Aging is an unavoidable stress with ever‐increasing detrimental effects on the brain microvasculature, which affects neuronal health/function and adds vulnerability to strokes and neurological diseases. In this study, we performed an extensive examination of proteins involved in the structure and function of mouse brain cortical microvessels (MVs) using a discovery‐based quantitative proteomic approach. Methods: Cortical MVs were isolated from age‐matched, male and female, young (4–6 months), middle‐aged (12–14 months), and old (20–21 months) mice obtained from Jackson Laboratory [Tg(Thy1‐EGFP)MJrs/J] (Jax No. 007788) and bred in a C57B16J background. The presence of end‐arterioles, capillaries, and venules in MVs was confirmed by light microscopy and by alkaline phosphate staining. Proteomics analysis was performed using liquid chromatography/mass spectrometry. Results: Most differentially expressed (DE) proteins (> 90%) showed no significant disparities between the sexes; however, some significant DE proteins showing sexual differences in MVs decreased from percentage in young (8.3%), to middle‐aged (3.7%), to old (0.5%) mice. Therefore, we combined male and female data for age‐dependent comparisons but noted sex differences for examination. Key proteins involved in the oxidative stress response, mRNA or protein stability, basement membrane (BM) composition, aerobic glycolysis, and mitochondrial function were significantly altered with aging. Relative abundance of superoxide dismutase‐1/‐2, catalase, and thioredoxin were reduced with aging. Proteins participating in either mRNA degradation or pre‐mRNA splicing were significantly increased in old mice MVs, whereas protein stabilizing proteins decreased. Glycolytic proteins were not affected in middle age, but the relative abundance decreased in MVs of old mice. Although most of the 41 examined proteins composing mitochondrial Complexes I‐V were reduced in old mice, six of these proteins showed a significant reduction in middle‐aged mice, but the relative abundance increased in fourteen proteins. Nidogen, collagen, and laminin family members as well as perlecan showed differing patterns during aging, indicating BM reorganization starting in middle age. Conclusions: We suggest that increased oxidative stress during aging leads to adverse protein profile changes of brain cortical MVs that affect mRNA/protein stability, BM integrity, and ATP synthesis capacity. [ABSTRACT FROM AUTHOR]