Molecular Regulation of Vascular Calcification in Diabetes

血管钙化和僵硬是糖尿病血管疾病的标志，糖尿病血管疾病是一种常见的心血管疾病。 导致退伍军人群体发病率和死亡率增加的并发症。退伍军人事务 糖尿病试验已经证明，血管钙化在退伍军人中升高，但降脂 他汀类药物未能抑制疾病进展。生物钟紊乱是军队中常见的问题 这对我们的许多退伍军人都有影响。异常的昼夜节律与 糖尿病心血管疾病加重。然而，昼夜节律异常在加速 糖尿病血管病变的发病机制尚不清楚。因此，本申请旨在了解 正常昼夜节律的破坏如何影响糖尿病患者的血管钙化和僵硬， 将填补尚未填补的科学空白。糖尿病常伴有高血糖和氧化应激， 已知其促进蛋白质O-GlcNAc化，这是一种关键的翻译后蛋白质修饰， 许多细胞过程。我们已经证明，在血管平滑肌细胞（VSMC）中， GlcNAc酰化/AKT/FOXO信号转导诱导主钙化因子Runx 2的表达， 促进VSMC钙化。在初步研究中，我们发现Runx 2的时间振荡 在体内小鼠动脉瘤和体外VSMC中，与BMAL 1（关键的昼夜节律调节因子）一起沿着表达。在 糖尿病小鼠动脉，O-GlcNAc化升高和BMAL 1表达增加， 与Runx 2的上调有关。此外，使用BMAL 1缺陷的VSMC，我们确定了一个 BMAL 1依赖性信号对VSMC中O-GlcNAc化的因果调节。因此，我们假设 “异常昼夜节律通过O-GlcNAc酰化促进糖尿病血管钙化- 调节FOXO/Runx 2信号轴。”利用我们新产生的诱导型SMC特异性OGT和BMAL 1 删除小鼠模型，该提案将揭示血管生物钟和O- GlcNAc酰化在糖尿病血管钙化调节中的作用及其分子机制 机制等从拟议的研究结果将推进我们的知识在理解的基本 糖尿病血管钙化的发病机制，这将提供重要的 在开发血管疾病的成功治疗中对临床意义的分子见解， 生物钟异常和O-GlcNAc化增加。

Vascular calcification and stiffness are hallmarks of diabetic vascular disorder, a prevalent cardiovascular complication that leads to increased morbidity and mortality in the Veteran's population. The Veterans Affairs Diabetes Trial has documented that vascular calcification was elevated in the Veterans, but the lipid-lowering statins failed to inhibit the disease progression. Disrupted circadian clock is a common issue in military personnel, which affects many of our Veterans. Abnormal circadian rhythm has been associated with exacerbated diabetic cardiovascular disease. However, the role of abnormal circadian rhythm in accelerating pathogenesis of diabetic vascular disease is not clear. Therefore, the current application aims to understand how disruption of normal circadian rhythms may affect vascular calcification and stiffness in diabetes, which would fill the unmet scientific gaps. Diabetes is often featured with both hyperglycemia and oxidative stress, which are known to promote protein O-GlcNAcylation, a key posttranslational protein modification that regulates numerous cellular processes. We have shown that in vascular smooth muscle cells (VSMC), elevated O- GlcNAcylation/AKT/FOXO signaling induces the expression of the master calcification factor, Runx2, thus promoting VSMC calcification. In preliminary studies, we uncovered a time-of-day oscillation of Runx2 expression along with BMAL1, the key circadian regulator, in mouse aortas in vivo and in VSMC in vitro. In diabetic mouse arteries, elevation of O-GlcNAcylation and increased expression of BMAL1 were identified, which was associated with upregulation of Runx2. Furthermore, using BMAL1 deficient VSMC, we determined a causative regulation of O-GlcNAcylation in VSMC by BMAL1-dependent signals. Therefore, we hypothesize that “Abnormal circadian rhythm promotes vascular calcification in diabetes through O-GlcNAcylation- regulated FOXO/Runx2 signaling axis.” With our newly generated inducible SMC-specific OGT and BMAL1 deletion mouse models, the proposal will uncover a novel causative role of vascular circadian clock and O- GlcNAcylation in regulating vascular calcification in diabetes; and delineate the underlying molecular mechanisms. Outcomes from the proposed studies will advance our knowledge in understanding of the basic mechanisms underlying pathogenesis of vascular calcification in diabetes, which should provide important molecular insights into clinical implications in the developing successful therapy for vascular disease featuring abnormal circadian clock and increased O-GlcNAcylation.