TNF-ALPHA AND BMP2-WNT SIGNALING IN DIABETIC VASCULAR DISEASE

描述(申请人提供)：西方化社会正在经历II型糖尿病(T2 DM)的流行，这与生活方式、肥胖和长寿有关。T2 DM是一种全身性血管疾病；广泛分布的低度动脉炎症、升高的肿瘤坏死因子-α水平和氧化应激破坏了大血管(如心脏、主动脉)和微血管(如视网膜、肾小球)的功能。T2 DM的一个高度特征是内侧动脉钙化(MAC)。MAC的主-股顺应性降低的负面后果已经显现；MAC扰乱了正常的Windkesel生理，导致收缩和舒张期功能障碍，增加了死亡率和截肢风险。预防或治疗MAC的能力代表着一种未得到满足的临床需求。更好地了解糖尿病和肾脏疾病(CKD)是如何促进MAC的，将为设计新的策略以减少血管钙负荷、保持主动脉顺应性和改善血管功能提供有益的见解。最近的数据表明糖尿病患者的主动脉BMP2-MSX2-Wnt信号被激活，均被英夫利昔单抗抑制。该项目的主要目标是评估靶向这些信号如何改善主动脉钙化、结构和顺应性。目的1：“检测用肿瘤坏死因子-α拮抗剂英夫利昔单抗或水杨酸盐抑制动脉BMP2-WNT诱导是否能改善糖尿病血管病变患者的主动脉顺应性。”通过使用体外视频体积描记术评估主动脉压-直径关系，我们将在一个相关的T2 DM模型--TOPGAL；LDLR-/-小鼠中建立肿瘤坏死因子-α与主动脉钙蓄积、Wnt信号和僵硬度之间的关系。将与RANKL抑制剂OPG的反应进行比较。目的2：研究肿瘤坏死因子-α通过NADPH氧化酶促进血管外膜成纤维细胞MSX2基因转录的机制。NAPDH氧化酶抑制剂载脂蛋白抑制肿瘤坏死因子-α(转录介导的)诱导的MSX2。通过识别传递MSX2诱导的信号级联反应对肿瘤坏死因子-α的反应，可以设计新的策略来抑制血管钙化。目的3：以p47Phox-/-、TOPGAL、LDLR-/-小鼠为模型，研究2型糖尿病大鼠主动脉BMP2-MSX-2-Wnt级联反应是否需要NADPH氧化酶信号转导。通过对p47Phox-/-；TOPGAL；LDLR-/-和p47Phox/-；TOPGAL；LDLR-/-对照进行表型分析，我们评估了这种由肿瘤坏死因子调节的氧化还原途径是否参与了HFD对BMP2-MSX2-Wnt的激活。

DESCRIPTION (provided by applicant): Westernized societies are experiencing an epidemic of type II diabetes (T2DM), related to life-style, obesity, and longevity. T2DM is a systemic vascular disorder; wide-spread low grade arterial inflammation, elevated TNF-alpha levels, & oxidative stresses disrupt macrovascular (e.g., heart, aorta) & microvascular (e.g. retina, renal glomerulus) functions. A highly characteristic feature of T2DM is medial artery calcification (MAC). The negative consequences of reduced aortofemoral compliance of MAC have emerged; MAC perturbs normal Windkessel physiology, causing systolic & diastolic dysfunction that increases mortality & amputation risk. The ability to prevent or treat MAC represents an unmet clinical need. A better understanding of how diabetes and kidney disease (CKD) promote MAC will provide insights useful for devising new strategies to reduce vascular calcium load, preserve aortic compliance, & improve vascular function. Recent data have identified activated aortic BMP2-Msx2-Wnt signaling in diabetic MAC--all inhibited by infliximab. The chief goal of this project is to assess how targeting these signals can improve aortic calcification, structure, & compliance. Aim 1: "To test whether inhibition of arterial BMP2- Wnt induction with theTNF-alpha antagonist infliximab or salicylate improves aortic compliance in diabetic vascular disease." By assessing aortic pressure- diameter relationships using ex vivo video plethysmography, we will establish the relationships between TNF-alpha & aortic calcium accumulation, Wnt signaling, and stiffness in a relevant T2DM model--the TOPGAL+; LDLR-/- mouse fed diabetogenic high fat diets (HFD). Comparison will be made with responses to the RANKL inhibitor, OPG. Aim 2: "To characterize the mechanisms whereby TNF- alpha signaling via NADPH oxidase promotes Msx2 gene transcription in aortic adventitial myofibroblasts." The NAPDH oxidase inhibitor, apocynin, inhibits Msx2 induction by TNF-alpha (transcriptionally mediated). By identifying the signaling cascades conveying Msx2 induction in response to TNF-alpha, novel strategies can be devised to inhibit vascular calcification. Aim 3: "To identify if NADPH oxidase signaling is required for induction of aortic BMP2-Msx-2-Wnt cascades in T2DM, using p47phox- /-; TOPGAL+; LDLR-/- mice as a model." By phenotyping p47phox-/-; TOPGAL+; LDLR-/- and p47phox+/-;TOPGAL+; LDLR-/- controls, we assess whether this TNF- regulated redox pathway contributes to aortic BMP2-Msx2-Wnt activation by HFD.