The Effects of Leptin on Dendritic Cells

瘦素是一种多效性细胞因子/激素，已被证明主要在食物摄入中起关键作用。 和能量消耗，但也是免疫系统功能的参与者，包括抗原的功能 递呈细胞(APC)。在构成APC的三个细胞群体中，只有一个是树突状细胞(DC) 有能力启动幼稚的T细胞反应。我们的目标是评估瘦素在DC中的潜在作用 功能，特别是当通过瘦素受体的信号受损时，例如在患有 患有肥胖症或II型糖尿病。我们发现，分析从瘦素缺乏症患者的脾中分离和浓缩的DC 小鼠(Lepob)，与脾DC相比，部分但不是全部DC功能受到影响 对照组C57BI/6小鼠。初步数据显示树突状细胞确实表达瘦素受体的长亚型。 因此可以对瘦素产生反应。瘦素缺乏不会改变DC表型，DC通过 炎性刺激或抗原加工；然而，瘦素缺乏确实影响DC获得 并有效地激活T细胞。我们还发现，外源性瘦素添加到骨骼中 骨髓来源的DC改变了DC的形态，促进了更多和更长的延伸，还 提高DC存活率。我们假设瘦素缺陷小鼠DC中的瘦素信号减少是由于 瘦素受体密度降低，正常情况下，瘦素可增强DC存活和树突状细胞 形成，从而增强APC-T细胞的相互作用，从而实现最佳的T细胞激活。我们建议 用三个具体的目标来解释我们的假设。目标1将确定该基因的相对表达水平 用标准Western印迹分析和Q-PCR检测DC上瘦素受体的异构体。目标2将 通过评估DC的诱导来确定瘦素在与T细胞共培养时是否提高DC的存活率 通过大量显微镜观察来确定瘦素是否能促进DC-T细胞的结合形成 技巧。最后，Aim 3将评估瘦素对DC信号事件的诱导作用。更确切地说， 促生存信号通路的诱导将通过生化方法和肌动蛋白重组的诱导进行评估。 将通过显微镜和生化分析进行评估。考虑到 Eeptin在DC成熟和功能中的作用(根据我们的初步数据)，抵抗瘦素信号 TAT发生在肥胖和2型糖尿病患者中，可能损害DC功能，从而损害T细胞介导的功能 免疫强调了了解瘦素在免疫中的作用的临床意义。

Leptin is a pleiotropic cytokine/hormone that has been shown to primarily play a critical role on food intake and energy expenditure but is also a participant in functions of the immune system, including that of antigen presenting cells (APCs). Of the three cell populations that constitute APCs, only one, dendritic cells (DC) have the ability to initiate naive T cell responses. Our goal is to assess the potential role of leptin on DC function particularly when signaling through the leptin receptor is compromised, such as in patients afflicted with obesity or Type II Diabetes. We have found, analyzing DC isolated and enriched from spleens of leptindeficient mice (Lepob), that some, but not all, of DC functions are affected when compared to splenic DC from control C57BI/6 mice. Preliminary data has shown that DC do express the long isoform of the leptin receptor and therefore can be responsive to leptin. Leptin-deficiency does not alter DC phenotype, DC activation by inflammatory stimuli, or processing of antigen; however, leptin-deficiency does affect DC ability to acquire antigen and to effectively activate T cells. We have also found that the addition of exogenous leptin to bone marrow-derived DC alters the morphology of the DC, promoting more and longer extensions and also enhances DC survival. We hypothesize that leptin signaling is reduced in DC from leptin-deficient mice due to a reduction in leptin receptor density and that normally, leptin enhances DC survival and dendrite formation thereby enhancing APC - T cell interactions leading to optimal T cell activation. We propose to address our hypothesis with three specific aims. Aim 1 will determine the relative expression levels of the ong isoform of the leptin receptor on DC using standard Western blot analysis and Q-PCR. Aim 2 will ascertain if leptin enhances DC survival when in co-culture with T cells by assessing the induction of DC apoptosis and will ascertain if leptin enhances DC - T cell conjugate formation by a number of microscopy techniques. Lastly, Aim 3 will evaluate the induction of signaling events in DC by leptin. More specifically, the induction of pro-survival signaling pathways will be evaluated biochemically and the induction of actin reorganization will be assessed via microscopy and biochemical assays. Considering the potential influence of eptin on DC maturation and function (as suggested by our preliminary data), resistance to leptin signaling tiat occurs in the obese and in type 2 diabetes may compromise DC function and thus T cell-mediated mmunity underscoring the clinical significance of understanding the role of leptin in immunity.