人脂肪细胞内源性多肽PDBSN用于肥胖治疗的应用基础研究

PDBSN is an endogenous peptide identified by peptidomics techniques. Its expression showed significant difference after human adipocyte differentiation without any function report. The concentration of PDBSN was significantly decreased in visceral adipose tissue from obese and high-fat diet induced mouse. Further study revealed that PDBSN could attenuate adipocyte differentiation and promote cellular energy consumption. Administration of PDBSN in C57BL6 mice fed a high-fat diet reduced body weight gain and improved insulin sensitivity, suggesting a potential treatment of obesity. We found C/EBPβ could combine with PDBSN by pull-down assay, which regulates adipocyte differentiation and energy metabolism. These demonstrated that PDBSN may exert its biological function through regulating C/EBPβ. To evaluate the role of PDBSN in anti-obesity, we verify its effect in various adipocytes and animal models. To elucidate the molecular mechanism of regulation of C/EBPβ, physical methods, rescue experiments and dual luciferase reporting system are carried out. To assess the feasibility of PDBSN in obesity treatment, we explore its toxicity and side effects, pharmacokinetics, tissue distribution and function after chemical modification. These studies may provide a new opportunity for the treatment of obesity.

PDBSN是我们借助多肽组学发现的、人脂肪细胞分化前后差异显著、功能未知的内源性多肽。前期发现，PDBSN存在于人与小鼠脂肪组织中，肥胖者及高脂喂养肥胖小鼠内脏脂肪组织中含量显著降低，具有抑制脂肪细胞分化、促进细胞能量代谢功能，给高脂喂养小鼠腹腔注射有显著的减重降糖效果，提示PDBSN具有潜在的肥胖治疗作用；Pull down实验发现，C/EBPβ为其可能结合靶标，而C/EBPβ是脂肪细胞分化早期调控因子且与细胞能量代谢有关，提示PDBSN可能通过调控C/EBPβ而发挥生物学作用。研究拟评估PDBSN在多种脂肪细胞、多种肥胖动物模型的功能一致性，论证其作为肥胖治疗手段的可能性；借助物理学方法、挽救实验策略、双荧光素酶报告系统，阐明其调控C/EBPβ的分子机制；通过揭示其毒副作用、药代动力学、组织分布特征、化学修饰后的功能，评估PDBSN作为肥胖治疗手段的可行性。研究可为肥胖治疗提供新契机。

肥胖是一种慢性营养障碍性疾病，是2型糖尿病、心脑血管疾病等重要危险因素，现已成为全球性的严重公共卫生问题。目前，肥胖防治策略十分缺乏，开发安全有效的干预手段已十分迫切。我们借助多肽组学，发现了一条在人脂肪细胞分化前后差异显著、功能未知的内源性多肽PDBSN。在人及小鼠脂肪组织样本进行检测发现，肥胖样品的脂肪组织中PDBSN水平低于正常的脂肪组织，且随脂肪细胞分化PDBSN水平逐渐降低，表明PDBSN水平与肥胖负相关。体外研究表明，PDBSN可抑制人、小鼠脂肪细胞分化，且不影响细胞增殖、细胞周期和凋亡。体内研究显示，PDBSN可降低高脂饮食诱导（HFD）的肥胖小鼠体重增长，改善葡萄糖耐受和胰岛素敏感性。进一步通过脂质体包裹PDBSN和内脏脂肪靶向肽配体修饰，提升PDBSN稳定性和靶向性。在体实验证明，修饰后的PDBSN可有效富集于内脏脂肪，且显著减缓HFD肥胖小鼠的体重增长和改善葡萄糖代谢水平。最后，通过转录组学和挽救实验对PDBSN的分子机制进行探索，发现AMPK信号通路是介导PDBSN生物学功能的关键作用机制。本研究系统阐明了PDBSN在脂肪组织中的含量及在脂肪细胞分化过程中的变化规律，以及体外与体内的功能，并对机制进行了初步的探索，研究成果不仅丰富了肥胖研究的理论基础，也为肥胖干预药物的研发提供新线索，有望为肥胖的防治提供新的手段，具有潜在的经济和社会价值。