Lamin A in Adipocyte Differentation and Survival

描述（由申请人提供）：已证明编码核纤层蛋白A和C的LMNA基因突变可引起Dunnigan型部分脂肪营养不良，这是一种常染色体显性遗传疾病，特征为局部脂肪丢失和胰岛素抵抗。这一发现暗示核纤层蛋白A和C，核被膜的中间丝蛋白，作为一个新的途径参与控制体脂分布的一部分。我们的假设是，核纤层蛋白A和C中的显性作用突变干扰了调节脂肪细胞分化或存活的这一途径。这项探索性研究项目的目标是确定Dunnigan型部分脂肪营养不良患者的突变核纤层蛋白A是否在体外和体外阻断脂肪细胞分化或降低脂肪细胞存活。 在具体目标1中，我们将研究3 T3-L1前脂肪细胞细胞系，其表达在Dunnigan型部分脂肪营养不良患者中发现的具有错义突变的野生型核纤层蛋白A。我们将检查这些细胞，并确定突变核纤层蛋白A是否阻止它们在体外分化为脂肪细胞或降低它们的存活率。在特定目标2中，我们将创建在Ap 2脂肪细胞活性启动子控制下表达野生型和突变体核纤层蛋白A的转基因小鼠品系。将在转基因小鼠中评估脂肪细胞分布，无论是在年轻时还是在老年时，因为在人类中，Dunnigan型部分脂肪营养不良中的脂肪损失发生在青春期开始后。探索性项目的工作将证明或反驳核纤层蛋白A在脂肪细胞发育或存活中起作用的假设。这一假设的证实将对确定治疗人类肥胖和糖尿病的新细胞靶点产生影响。

DESCRIPTION (provided by applicant): Mutations in the LMNA gene that encodes nuclear lamins A and C have been shown to cause Dunnigan-type partial lipodystrophy, an autosomal dominant inherited disease characterized by regional fat loss and insulin resistance. This finding implicates lamins A and C, intermediate filament proteins of the nuclear envelope, as part of a novel pathway involved in the control of body fat distribution. Our hypothesis is that dominantly acting mutations in lamins A and C interfere with this pathway that regulates fat cell differentiation or survival. The goal of this exploratory research project is to determine if mutant lamin A from patients with Dunnigan-type partial lipodystrophy blocks adipocyte differentiation or decreases adipocyte survival in vitro and in vitro. In Specific Aim 1, we will study 3T3-L1 pre-adipocyte cell lines that express wild-type lamin A with missense mutations found in patients with Dunnigan-type partial lipodystrophy. We will examine these cells and determine if the mutant lamin A blocks their in vitro differentiation into adipocytes or decreases their survival. In Specific Aim 2, we will create transgenic mouse lines that express wild-type and mutant lamin A under control of an Ap2 adipocyte-active promoter. Adipocyte cell distribution will be assessed in the transgenic mice, both at young and older ages as, in humans, fat loss in Dunnigan-type partial lipodystrophy occurs after the onset of puberty. The work in the exploratory project will prove or disprove the hypothesis that nuclear lamin A functions in fat cell development or survival. Confirmation of this hypothesis will have implications for the identification of new cellular targets to treat human obesity and diabetes mellitus.