Project 10 - The role of nanoformulated Cu/ZnSOD in reducing systemic hypertensi

虽然氧化应激是肥胖的一种普遍情况，但由超氧化物引发的氧化应激在肥胖中调节脂肪组织（AT）特异性炎症中的作用尚不清楚。此外，抗氧化剂在调节肥胖AT的炎症状态和随后的全身性高血压发展中的潜在作用尚不清楚。我们的初步数据表明，用纳米配方的铜/锌超氧化物歧化酶（nanoSOD）预处理人主动脉内皮细胞，而不是天然或PEG-SOD，可以减少亚油酸诱导的超氧化物的产生。我们的体内数据表明，纳米超氧化物歧化酶可以减少肥胖AT中超氧化物介导的氧化应激，这一点从AT间质血管部分中硝基酪氨酸含量的降低可以看出。由于氧化应激通常与炎症有关，而且AT特异性炎症介导肥胖的病理后果，我们假设使用纳米超氧化物歧化酶（nanoSOD）减少AT超氧化物会导致AT炎症减少，从而导致肥胖的全身性高血压降低。本申请中提出的研究将采用生理学、药理学和分子方法来研究在肥胖中使用纳米超氧化物歧化酶减少超氧化物如何影响全身性高血压的发展。由于内皮细胞氧化应激是与肥胖和高血压相关的潜在事件，我们将在Specific Aim 1中确定纳米超氧化物歧化酶在向内皮细胞输送活性超氧化物歧化酶和清除游离脂肪酸诱导的超氧化物中的作用。在特异性目标2中，我们将确定SOD作为纳米SOD在饮食性肥胖模型中的生物分布。野生型小鼠喂食高脂肪饮食（45%脂肪）12周，并注射1251标记的纳米sod。将进行SPECT成像以确定SOD在组织中的生物分布，包括内脏AT，肝脏和脾脏。在特异性目标3中，我们将确定纳米sod在饮食诱导肥胖模型中的毒性。我们还将研究纳米超氧化物歧化酶在清除AT超氧化物和降低肥胖患者全身性高血压方面的有效性。简单地说，在高脂肪饮食12周后，小鼠将接受2周的纳米酶。在14周结束时，我们将分析At超氧化物、At炎症和全身性高血压。这一发现将有助于确定纳米配方抗氧化酶治疗肥胖症慢性心血管危险因素的治疗潜力。

Although oxidative stress is a prevalent condition in obesity, the role of oxidative stress initiated by superoxide in modulating adipose tissue (AT)-specific inflammation in obesity remains unclear. Moreover, the potential role of antioxidants in modulating the inflammatory state of obese AT and subsequent development of systemic hypertension is unknown. Our preliminary data show that pretreatment of human aortic endothelial cells with nanoformulated copper/zinc superoxide dismutase (nanoSOD) but not native or PEG-SOD reduces linoleic acid-induced superoxide production. Our in vivo data show that nanoSOD reduces superoxide-mediated oxidative stress in obese AT as evident from decreased nitrotyrosine content in the AT stromal vascular fraction. Because oxidative stress is often associated with inflammation and because AT-specific inflammation mediates the pathological consequence of obesity, we hypothesize that reduction of AT superoxide using nanoSOD will lead to reduced AT-inflammation which, in turn, will lead to reduced systemic hypertension in obesity. The studies proposed in this application will take physiological, pharmacological, and molecular approaches to investigate how reduction of superoxide using nanoSOD in obesity will impact the development of systemic hypertension. Because endothelial cell oxidative stress is an underlying event linking obesity and hypertension, we will determine the role of nanoSOD in delivering active SOD to endothelial cells and in scavenging free fatty acid-induced superoxide in Specific Aim 1. In Specific Aim 2, we will determine the biodistribution of SOD delivered as nanoSOD in a model of diet induced obesity. Wild type mice will be fed a high fat diet (45% fat) for 12 wk and injected with 1251-labelled nanoSOD. SPECT imaging will be carried out to determine the biodistribution of SOD in tissues including visceral AT, liver, and spleen. In Specific Aim 3, we will determine the toxicity of nanoSOD in a model of diet-induced obesity. We will also study the effectiveness of nanoSOD in scavenging superoxide from AT and in reducing systemic hypertension in obesity. Briefly, after 12 wk on high fat diet, the mice will receive the nanozymes for 2 wk. At the end of 14 wk, we will analyze AT superoxide, AT-inflammation and systemic hypertension. The findings will be relevant to determining the therapeutic potential of nanoformulated antioxidant enzymes in treating chronic cardiovascular risk factors in obesity.