The Role of PTEN in B-cell regeneration through epithelial-mesenchymal transition

描述(申请人提供)：I型糖尿病的特征是细胞丢失。为了开发治疗方法，我们需要了解这些细胞是如何再生的。这项提议的目标是了解细胞再生是如何被调控的。我们将重点放在PTEN(10号染色体上缺失的磷酸酶和张力蛋白同源物)上，并表明Pten的缺失会导致胰岛质量增加。我们假设PTEN缺乏通过调节细胞动力学和可塑性来增加胰岛质量。为了检验这一假设，我们设定了两个具体目标。在Aim1中，我们将确定PTEN对胰岛质量的影响是否是细胞自主的。将使用两种方法来测试PTEN在细胞再生方面的自主性质。使用PtenloxP/loxP；RosalacZ；Rip-Cre+小鼠进行谱系追踪，研究PTEN在细胞增殖中的作用将是第一种方法。以前，我们已经观察到PTEN缺乏导致胰岛质量增加，同时胰岛附近的增殖增加。在这项研究中，我们将确定这些增殖的胰岛周细胞是否起源于细胞，以及它们是否有助于胰岛再生。为了进一步测试PTEN的作用是否对细胞自主，我们将确定PTEN对细胞再生的影响是否依赖于它在发育中的作用。为此，我们将使用我们建立的PtenloxP/loxP；RosalacZ；Rip-Creer+模型在成熟细胞中诱导Pten缺失。在AIM2中，我们将研究PTEN诱导细胞再生的机制。我们观察到Pten突变胰腺中间充质细胞的形成增加。由于小鼠的间充质细胞最有可能是自我再生的，所以这些间充质细胞很可能是处于去分化过程中的细胞，因为它们不表达胰岛素。为了阐明PTEN如何调节细胞的可塑性，我们将研究PTEN在上皮间充质转化(EMT)中的作用。EMT被认为是细胞再生的一种机制。我们将使用PtenloxP/loxP；RosalacZ；Rip-Cre+小鼠的谱系追踪来确定这些间充质细胞是否真的是经历EMT的细胞，以及它们是否有助于细胞再生。综上所述，这一应用主要集中在细胞再生的机制上。这项研究的结果将为靶向PI3K/AKT信号通路治疗I型糖尿病的可行性提供机制分析。这项拟议的研究侧重于了解胰腺细胞再生的机制。刺激细胞再生是开发针对I型糖尿病的药物治疗的重要目标。这项拟议的研究对PTEN在细胞再生中的作用进行了机制分析，PTEN是一个关键的生长调节因子。如果这一假说得到证实，这项研究将为靶向PTEN调节的PI3K/AKT通路以刺激细胞再生的药物提供分子基础。

DESCRIPTION (provided by applicant): The hallmark of type I diabetes is the loss of ¿-cells. In order to develop therapies, we need to understand how these cells can be regenerated. The goal of this proposal is to understand how ¿-cell regeneration is regulated. We have focused on PTEN (phosphatase and tensin homologue deleted on chromosome 10) and shown that deletion of Pten leads to increased islet mass. We hypothesize that PTEN deficiency increases islet mass by regulating ¿-cell dynamics and plasticity. To test this hypothesis, we have set two specific aims. In Aim1, we will determine whether the effect of PTEN on islet mass is cell autonomous to ¿-cells. Two approaches will be used to test the autonomous nature of PTEN on ¿-cell regeneration. Lineage tracing using PtenloxP/loxP; RosalacZ; Rip-Cre+ mouse to investigate the role of PTEN in ¿-cell proliferation will be the first approach. Previously, we have observed that PTEN deficiency leads to increased islet mass in conjunction with an increased proliferation near the islets. In this study, we will determine whether these proliferating peri-islet cells originate from ¿-cells and whether they contribute to islet regeneration. To further test if the effect of PTEN is cell autonomous to ¿-cells, we will determine whether the effect of PTEN on ¿-cell regeneration is dependent on its role in development. To do this, we will use the PtenloxP/loxP; RosalacZ; Rip-CreER+ model that we have generated to induce Pten deletion in mature ¿-cells. In Aim2, we will investigate the mechanism for PTEN induced ¿-cell regeneration. We have observed increased mesenchymal cell formation in the Pten mutant pancreas. Since mouse ¿-cells are most likely self regenerating, it is likely that these mesenchymal cells are ¿-cells in the process of dedifferentiation as they do not express insulin. To address how PTEN regulates ¿-cell plasticity, we will investigate the role of PTEN on epithelial mesenchymal transition (EMT) in ¿-cell regeneration. EMT has been suggested to be one mechanism that ¿-cells may use to regenerate. We will use lineage tracing with the PtenloxP/loxP; RosalacZ; Rip-Cre+ mouse to determine if these mesenchymal cells are indeed ¿-cells going through EMT and whether they contribute to ¿-cell regeneration. In summary, this application is focused on the mechanism of ¿-cell regeneration. The result of this study will provide a mechanistic analysis of the feasibility of targeting the PI3K/AKT signal pathway in order to treat type I diabetes. The proposed study is focused on understanding the mechanism for pancreatic ¿-cell regeneration. Stimulating ¿-cell regeneration is an important goal for developing drug treatments targeted at type I diabetes. The proposed study provides a mechanistic analysis of the role of PTEN, a key growth regulator, in ¿-cell regeneration. If the hypothesis is proven, this study will provide a molecular basis for drugs designed to target the PTEN regulated PI3K/AKT pathway in order to stimulate ¿-cell regeneration.