一种新的脂肪细胞特异性核酸适体的功能研究及靶标确定

Adipose tissue is one of the most important target tissue for the treatment of obesity, but currently there are no drugs that can target specifically to this tissue. Previously, we have selected a set of nucleic acid aptamers, among which Adipo 8 not only shows high binding ability and affinity, but also have the function of reducing fatty droplet and cell number in 3T3-L1 cell lines. Thus, we propose the hypothesis that Adipo 8 modulate its downstream signal pathways through binding with a specific receptor on cell membrane, resulting in reduction of fatty droplet and adipocyte number, and finally prevent the accumulation of fatty acid within adipose tissue. To elucidate the underlying mechanisms account for above-mentioned functions of aptamer Adipo 8, this project was designed to investigating the effects of adipogenesis inhibition, lipolysis promotion and apoptosis induction of Adipo 8 by using classical adipocyte and mouse model; employing the Adipo 8 as a molecular probe to separate and enrich its target on adipocyte membrane, identifying its target candidates through mass spectrometry, and then reconfirming by flow cytometry & molecular imaging technologies.The study is expected to provide new ideas and theoretical basis for the development of new anti-obesity drugs, and a new molecular tool for targeted delivery of drugs specific to adipose tissue as well.

脂肪组织是肥胖治疗最重要的靶组织之一，但目前尚无特异性作用于该组织的药物。我们首次运用Cell-SELEX技术从白色脂肪组织脂肪细胞筛选了一条核酸适体Adipo 8，其不仅与脂肪细胞高亲和力高特异性结合，还能使脂肪细胞脂滴及数量明显减少。由此我们提出Adipo 8通过结合脂肪细胞上某特异的膜蛋白，调控其下游信号通路减少脂肪细胞脂肪含量及数量的作用而抑制白色脂肪组织积聚的科学假说。本项目拟从细胞和动物水平探索Adipo 8产生上述功能的机制：研究Adipo 8对脂肪细胞成脂及分化的抑制、脂解的促进及凋亡的诱导作用；运用Adipo 8作为分子探针，实现其结合的脂肪细胞膜靶标的分离与富集，并利用质谱技术进行相关靶标的鉴定，再利用基于核酸适体Adipo 8的分子成像技术与流式细胞技术进行靶标的确定。本研究可望为防治肥胖新药物的开发提供理论依据和新思路，为肥胖靶向治疗提供一种全新的分子工具。

脂肪组织是肥胖治疗最重要的靶组织之一，但目前尚无特异性作用于该组织的药物。前期我们运用Cell-SELEX技术从白色脂肪组织脂肪细胞筛选了一条核酸适体Adipo 8，其不仅与脂肪细胞高亲和力高特异性结合，还能使脂肪细胞脂滴及数量明显减少。我们提出Adipo 8通过结合脂肪细胞上某特异的膜蛋白，并通过膜蛋白下游信号通路调控脂肪细胞代谢并减少脂肪细胞脂肪含量及数量，抑制白色脂肪组织积聚的科说。验证这一科学假说将为脂肪细胞代谢调控机理的阐明及防治肥胖药物及载体的开发提供新的证据。我们从细胞和动物水平两个层次探索 Adipo 8减少脂肪细胞脂肪含量及数量的功能及机制；研究 Adipo 8对脂肪细胞抑制成脂分化、促进脂解及诱导凋亡的作用，并阐明其调控机理；运用 Adipo 8作为分子工具，实现其结合的脂肪细胞膜靶标的发现、鉴定和确定。发现了Adipo 8与分化成熟后的3T3-L1脂肪细胞的结合靶标。另外，我们构建了核酸适体Adipo8-金纳米粒子复合物，发现修饰了核酸适体Adipo8和载药DNA的金纳米粒子能选择性地进入到靶细胞内，并释放Dox对3T3-L1细胞进行杀伤。证实Adipo8对靶细胞的稳定结合能力，以及借助纳米粒子，存在靶向载药的可能性。本研究可望为防治肥胖新药物的开发提供理论依据和新思路，为肥胖靶向治疗提供全新有效的分子工具。