Apoptosis pathways underlying adipogenesis

脂肪生成的细胞凋亡途径

• 批准号: 8774174
• 负责人: Niketa A. Patel
• 金额: --
• 依托单位: JAMES A. HALEY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8774174
• 关键词: Accounting; Adipocytes; Adipose tissue; Adult; Affect; Alternative Splicing; Apoptosis; Apoptotic; Behavioral; Cardiovascular Diseases; Cause of Death; Cell Survival; Complement; Curcumin; Data; Development; Diet; Disease; Epidemic; Event; Exhibits; Expenditure; Fatty acid glycerol esters; Future; Gene Expression; General Population; Genes; Genetic; Genomics; Goals; Health; Health Care Costs; Healthcare; High Prevalence; Intervention; Knowledge; Link; Measures; Mediating; Mediator of activation protein; Medical; Mesenchymal; Metabolic syndrome; Molecular; Morbidity - disease rate; Non-Insulin-Dependent Diabetes Mellitus; Obese Mice; Obesity; Outcome; Overweight; Pathway interactions; Phenotype; Phosphotransferases; Physiological; Population; Prevalence; Prevalence Study; Preventive; Protein-Serine-Threonine Kinases; Public Health; RNA Splicing; Research; Resveratrol; Risk Factors; Role; Services; Signal Transduction; Socioeconomic Factors; Spliced Genes; Therapeutic; Therapeutic Intervention; Tissues; Transcriptional Regulation; Variant; Veterans; Weight; Weight Gain; adipocyte differentiation; base; cancer type; caspase-9; combat; design; feeding; inhibitor/antagonist; innovation; lipid biosynthesis; mouse model; obesity treatment; overexpression; precursor cell; prevent; programs; research study; therapeutic evaluation; upstream kinase

DESCRIPTION (provided by applicant): Obesity continues to escalate as a significant public health problem and as the leading preventable cause of death. Genetic, environmental, behavioral, and socioeconomic factors cause excess weight gain and obesity. Increased proliferation and differentiation of pre-adipocytes to mature adipocytes (adipogenesis) within the fat tissues are central to obesity. Previous studies focused extensively on the transcriptional controls which maintain the adipocyte phenotype. However, the underlying molecular mechanisms that promote determination of primitive mesenchymal precursor cells to the adipose phenotype are still unknown. Our long-term goal is to elucidate the cellular and molecular mechanisms underlying adipogenesis. In pursuit of this goal, our objective is to determine how alternative splicing of apoptotic genes govern the differentiation and maturation of pre-adipocytes. It is well documented that pre-adipocytes undergo apoptosis while mature adipocytes fail to do so. Based on preliminary data, our central hypothesis is that there is a distinct shift in the expression of genes involved in apoptosis from a pro-apoptotic to a pro-survival pathway via alternative splicing controlling terminal adipocyte differentiation which ultimately increases the adipose number and mass leading to obesity. The significance of the proposed research is that once we establish the molecular mechanisms of adipogenesis which result in increased survival of adipocytes, we can manipulate targets of the apoptosis pathway to devise new and innovative approaches to prevent or reverse weight gain and obesity. We propose three specific aims. In Aim 1, we will elucidate whether terminal adipocyte differentiation is accompanied by alternative expression of apoptosis genes. Pre-adipocytes undergo apoptosis unlike mature adipocytes. Our data demonstrate that during adipocyte differentiation between days 4-6, expression of Bcl2 and Bcl-x, caspase 9 and PKC4 alternatively spliced variants change to its pro-survival variants. Using overexpression and knockdown experiments, we will elucidate the link between these genes, adipogenesis and apoptosis. Aim 2 is designed to determine the role of the signaling kinase PKC4II as an anti-adipogenic mediator. PKC4II, a serine/threonine protein kinase promotes cell survival. Natural compounds such as resveratrol and curcumin exhibit anti-adipogenic activities and promote apoptosis in adipocytes. Our data shows that they inhibit PKC4II expression. Our data further points to PKC4II as the signaling kinase upstream of Bcl2-mediated survival pathway. We propose to identify the intracellular target which is central to pro-survival pathways in adipocytes that may be modulated to induce anti-adipogenic effects. In Aim 3 the physiological relevance of this hypothesis will be assessed determining the expression levels of these apoptosis genes in diet-induced obese mouse model (C57BL/6) fed a high-fat diet complemented with the natural compounds or a PKC4II-specific inhibitor. By showing that alternative splicing of apoptotic genes modulate differentiation and maturation of pre-adipocytes, the proposed studies will establish a new paradigm for adipogenesis and reveal new targets for treatment of obesity.

描述（由申请人提供）： 肥胖症继续升级为重大的公共卫生问题，也是可预防的死亡原因。遗传，环境，行为和社会经济因素会导致体重增加和肥胖。脂肪组织中脂肪细胞前脂肪细胞对成熟脂肪细胞（脂肪生成）的增殖增加和分化是肥胖症的核心。先前的研究广泛关注维持脂肪细胞表型的转录对照。但是，促进原始间充质前体细胞对脂肪表型的确定的基本分子机制仍然未知。我们的长期目标是阐明脂肪生成的基础机制和分子机制。为了实现这一目标，我们的目标是确定凋亡基因的替代剪接如何控制前脂肪细胞的分化和成熟。有充分的文献证明，脂肪细胞会发生凋亡，而成熟的脂肪细胞无法做到。基于初步数据，我们的中心假设是，通过控制终末脂肪细胞分化的替代剪接，凋亡与凋亡相关的基因表达发生了明显的转变，最终增加了脂肪的数量和质量。拟议的研究的重要性是，一旦我们建立了脂肪生成的分子机制，从而增加了脂肪细胞的存活率，我们就可以操纵凋亡途径的靶标，以设计新的创新方法，以预防或反向体重增加和肥胖。 我们提出了三个具体目标。在AIM 1中，我们将阐明末端脂肪细胞分化是否伴随着凋亡基因的替代表达。与成熟的脂肪细胞不同，脂肪细胞会经历凋亡。我们的数据表明，在第4-6天之间的脂肪细胞分化过程中，BCL2和BCL-X的表达，caspase 9和PKC4替代剪接变体变为其亲生型变体。使用过表达和敲低实验，我们将阐明这些基因，脂肪形成和凋亡之间的联系。 AIM 2旨在确定信号激酶PKC4II作为抗辅助介质的作用。 PKC4II，一种丝氨酸/苏氨酸蛋白激酶可促进细胞存活。天然化合物（例如白藜芦醇和姜黄素）表现出抗辅助活性，并促进脂肪细胞中的凋亡。我们的数据表明它们抑制了PKC4II的表达。我们的数据进一步指出PKC4II是Bcl2介导的生存途径上游的信号激酶。我们建议鉴定细胞内靶标，该靶标对于脂肪细胞中的临床途径至关重要，脂肪细胞可能会调节以诱导抗源源异构作用。在AIM 3中，将评估该假设的生理相关性，以确定饮食诱导的肥胖小鼠模型（C57BL/6）中这些凋亡基因的表达水平，喂养了具有天然化合物或PKC4II特异性抑制剂的高脂饮食。 通过显示凋亡基因的替代剪接调节脂肪细胞的分化和成熟，拟议的研究将建立一个新的脂肪形成范式，并揭示用于治疗肥胖症的新靶标。