Abstract：
Diabetes mediates endothelial dysfunction and increases the risk of Alzheimer\'s disease and related dementias. Diabetes also dysregulates the ET system. ET-1-mediated constriction of brain microvascular pericytes (BMVPCs) has been shown to contribute to brain hypoperfusion. Cellular senescence, a process that arrests the proliferation of harmful cells and instigates phenotypical changes and proinflammatory responses in endothelial cells that impact their survival and function. Thus, we hypothesized that ET-1 mediates BMVPC senescence and phenotypical changes in diabetes-like conditions. Human BMVPCs were incubated in diabetes-like conditions with or without ET-1 (1 µmol/L) for 3 and 7 days. Hydrogen peroxide (100 µmol/L H2O2) was used as a positive control for senescence and to mimic ischemic conditions. Cells were stained for senescence-associated β-galactosidase or processed for immunoblotting and quantitative real-time PCR analyses. In additional experiments, cells were stimulated with ET-1 in the presence or absence of ETA receptor antagonist BQ-123 (20 μmol/L) or ETB receptor antagonist BQ-788 (20 μmol/L). ET-1 stimulation increased β-galactosidase accumulation which was prevented by BQ-123. ET-1 also increased traditional senescence marker p16 protein and pericyte-specific senescence markers, TGFB1i1, PP1CA, and IGFBP7. Furthermore, ET-1 stimulated contractile protein α-SMA and microglial marker ostepontin in high glucose suggesting a shift toward an ensheathing or microglia-like phenotype. In conclusion, ET-1 triggers senescence, alters ETA and ETB receptors, and causes phenotypical changes in BMVPCs under diabetes-like conditions. These in vitro findings need to be further studied in vivo to establish the role of ETA receptors in the progression of pericyte senescence and phenotypical changes in VCID.
摘要：
糖尿病介导内皮功能障碍并增加阿尔茨海默病和相关痴呆的风险。糖尿病也失调ET系统。ET-1介导的脑微血管周细胞（BMVPC）的收缩已被证明有助于脑灌注不足。细胞衰老,阻止有害细胞增殖的过程，刺激内皮细胞的表型变化和促炎反应，影响其生存和功能。因此，我们假设ET-1介导糖尿病样疾病中BMVPC衰老和表型改变.将人BMVPC在有或没有ET-1（1μmol/L）的糖尿病样条件下孵育3天和7天。过氧化氢（100μmol/LH2O2）用作衰老和模拟缺血条件的阳性对照。对细胞进行衰老相关的β-半乳糖苷酶染色或处理用于免疫印迹和定量实时PCR分析。在额外的实验中，在存在或不存在ETA受体拮抗剂BQ-123（20μmol/L）或ETB受体拮抗剂BQ-788（20μmol/L）的情况下，用ET-1刺激细胞。ET-1刺激增加了β-半乳糖苷酶的积累，这被BQ-123阻止。ET-1还增加了传统的衰老标记p16蛋白和周细胞特异性衰老标记，TGFB1i1,PP1CA,IGFBP7此外，ET-1在高糖条件下刺激收缩蛋白α-SMA和小胶质细胞标记骨桥蛋白，表明向鞘膜或小胶质细胞样表型转变。总之,ET-1引发衰老,改变ETA和ETB受体，并导致糖尿病样条件下BMVPCs的表型变化。这些体外发现需要在体内进一步研究，以确定ETA受体在周细胞衰老进程和VCID表型变化中的作用。
