神经肽Y剂量依赖性调节脂滴形成参与肥胖及脂代谢的机制与应用

Obesity and related metabolic complications were closely associated with hyperphagia. As a critical orexigenic factor,neuropeptide Y(NPY) plays bidirectional effects on numerous physiological processes. Recent studies had shown that NPY could play its peripheral effect on adipose tissue growth which leading to obesity without metabolic disorders. Changing the expression levels of lipid droplet associated proteins may cause lipid droplets size shrink and reduce neutral lipid storage capacity which resulted in the release of free fatty acid, which were one of the reasons of leading to metabolic disorders. We previously found that high-dose NPY increased the lipid droplets size significantly. Here we hypothesis that high-dose NPY increase lipid droplets size through acting on the lipid droplets associated proteins, which thereby enhance neutral lipid storage capacity and suppress the release of harmful lipid such as free fatty acid (FFA) .To verify the above mentioned hypothesis, we will confirm the exact approach of promoting effect of high-dose NPY on lipid droplets by utilizing live cell imaging through confocal microscopy as well as using a novel mathematical computational algorithms to calculating the total volume of lipid droplets; Then lipid droplets will be isolated and purified, differential proteomics analysis will be used to screen out the lipid droplets associated proteins which relative with the role of NPY on lipid droplets. Finally, we will further validate the mechanism of effect of peripheral NPY on obesity and lipid metabolism through lipid droplet associated proteins directly, which would provide a new therapeutic targets for various type of metabolic disorder individuals.

肥胖及相关代谢并发症与饮食过度密切相关，神经肽Y（NPY）作为一种重要的促食欲因子，对机体既有益又有害。最新发现，其外周促脂肪生长作用所致的肥胖个体不会发生代谢并发症；而代谢并发症发生的原因之一在于脂滴表面蛋白表达变化导致脂滴体积缩小、存储中性脂肪能力下降，游离脂肪酸增多而损害靶组织。我们前期研究发现高剂量的NPY能明显促进脂滴体积增大。因此我们假设高剂量NPY能直接作用于脂滴表面相关蛋白，促进脂滴体积变大，增加中性脂质储存容量，抑制有害游离脂肪酸释放。为此我们将运用共聚焦活体细胞成像、模拟数学公式计算来确定高浓度NPY促进脂滴体积变大的具体途径；分离纯化脂滴，差异蛋白组学筛选出NPY直接作用的脂滴蛋白，通过体内外试验验证外周NPY通过脂滴蛋白影响肥胖及脂代谢的机制，为不同类型体型人群代谢异常的干预提供靶点。

神经肽Y作为目前最强的一种促食欲肽，在肥胖及相关的能量代谢过程中发挥重要作用。我们通过体外实验发现脂肪细胞在外界营养受限（无血清培养）的情况下，脂源性NPY的表达明显升高，并进一步明确外源性高浓度NPY通过抑制脂解及促进脂质合成来参与脂肪代谢过程。我们进一步通过构建成年小鼠禁食-再喂养模型，研究了外界饮食限制对不同脂肪组织中NPY的mRNA水平的具体影响，发现NPY在不同脂肪组织中的表达变化具有组织特异性且在肠系膜脂肪组织表达显著升高；进一步通过HE染色、电镜分析及分子生物学实验明确了禁食对不同脂肪组织的可塑性差异，证实发现肠系膜内脏脂肪组织在禁食后最先受到影响，而再喂养后恢复更慢。该脂肪可塑性差异在不同年龄小鼠体内进一步得到体现，即15月龄小鼠相比于1月龄及3月龄其可塑性更差，在遭受禁食刺激后脂肪组织恢复更为缓慢。我们进一步通过高通量表达谱芯片研究成年小鼠肠系膜内脏脂肪组织 lncRNAs 在禁食再喂养后的表达谱特征，筛选了一批营养代谢敏感的 lncRNAs，并进一步发现了脂源性lnc-FR332443可以通过调节三羧酸循环中IDH3α的表达水平参与脂肪组织能量代谢。最后我们分析了不同肥胖表型人群中血清神经肽Y水平，证实代谢异常型肥胖人群的血清NPY水平高于代谢健康型肥胖人群，且探明NPY是代谢异常性肥胖表型重要的独立危险因素，两者间存在非线性关系及阈值效应，高浓度的NPY与MUO表型存在显著的正相关。因此，本项目进一步对NPY参与脂质代谢的作用进行了较为全面的探讨，并从非编码RNA水平对饮食限制调节脂肪组织能量代谢的过程进行了深入探讨，为肥胖及其相关代谢性疾病的防控提供更多的理论依据。