The role of SerpinB2 in insulin resistance and inflammation

SerpinB2 在胰岛素抵抗和炎症中的作用

• 批准号: 10615780
• 负责人: Partha Dutta
• 金额: $ 46.38万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10615780
• 关键词: Adipose tissue; Age; Alteplase; Anti-Inflammatory Agents; Apoptosis; Apoptotic; Binding; Body mass index; Caspase; Cells; Data; Diabetes Mellitus; Disease; Exhibits; Frequencies; GKLF protein; Genetic Transcription; Glucose Clamp; Hematopoietic; Human; Hyperinsulinism; In Vitro; Individual; Inflammation; Inflammatory; Insulin Resistance; Interferon Gamma Receptor Complex; Interferon Type II; Interleukin-1 beta; Interleukin-13; Interleukin-4; Knowledge; MAPK3 gene; Macrophage; Malignant Neoplasms; Measures; Mediating; Metabolic syndrome; Mitogen-Activated Protein Kinases; Molecular; Mus; Nematode infections; Obese Mice; Obesity; Pathogenesis; Pathologic; Patients; Plasminogen Activator Inhibitor 1; Plasminogen Activator Inhibitor 2; Play; Prevention; Process; Production; Proteins; Role; Serine Proteinase Inhibitors; Small Interfering RNA; Source; T-Lymphocyte; TNF gene; Testing; Thinness; Tissues; Urokinase; Visceral; Wild Type Mouse; cytokine; diabetic patient; drug development; experimental study; extracellular signal-regulated kinase 4; glucose tolerance; impaired glucose tolerance; improved; in vivo; inhibitor; insulin sensitivity; insulin tolerance; monocyte; nanoparticle; non-diabetic; overexpression; promoter; receptor; transcription factor; transcriptome; transglutaminase 2

Project Summary/ Abstract: Plasminogen activator inhibitor type 1 (PAI-1) and type 2 (PAI-2) are serine protease inhibitors of tissue plasminogen activator and urokinase. PAI-2, which is encoded by SerpinB2, has been shown to be critical to the pathogenesis of different diseases including cancer and nematode infection. However, its role in obesity- associated insulin resistance is not known. Our preliminary experiments revealed that diabetic patients harbored significantly reduced number of SerpinB2+ cells in omental adipose tissue compared to non-diabetic individuals. Moreover, we observed an inverse correlation between the frequency of SerpinB2+ cells and body mass index in patients, suggesting a protective role of SerpinB2 in diabetes. Consistently, SerpinB2-deficient mice exhibited impaired glucose tolerance. Among all hematopoietic cells in visceral adipose tissue (VAT), only resident macrophages expressed detectable and high amount of SerpinB2. This macrophage subset had significantly reduced SerpinB2 expression in obese humans and mice compared to lean control. Furthermore, VAT of obese humans and mice contained diminished number of resident macrophages due to their high apoptosis, which is in line with the well-known anti-apoptotic role of SerpinB2. Additionally, we found that SerpinB2 is essential for the production of anti-inflammatory cytokines, such as IL-4 and IL-13, by VAT resident macrophages. These cytokines are crucial for maintaining insulin sensitivity. Based on these observations, we hypothesize that reduced SerpinB2 expression in obesity triggers VAT resident macrophage apoptosis, increases inflammation and promotes insulin resistance. We will test this hypothesis in two specific aims. Aim. 1. To determine the role of SerpinB2 in insulin resistance, we will use 3-fold approaches: a) SerpinB2-/- mice, b) macrophage-specific SerpinB2-deficient mice (LysMcre/+ SerpinB2fl/fl) and c) SerpinB2 silencing in VAT macrophages in vivo in wild type mice using siRNA formulated in lipidoid nanoparticles. Furthermore, we will determine if T cell-derived IFN-γ in obesity decreases SerpinB2 expression. We will also test if SerpinB2- mediated production of anti-inflammatory cytokines depends on Kruppel-like factor 4 (Klf4) and mitogen activated protein kinase (MAPK) activators ERK1/2. Aim. 2. We will investigate the molecular mechanisms of the prevention of apoptosis by SerpinB2. Our preliminary data demonstrated that SerpinB2-deficient macrophages contained diminished levels of transglutaminase 2 (TG2), a known modulator of caspase. Additionally, we observed that SerpinB2 directly binds to TG2. To determine if anti-apoptotic effect of SerpinB2 is TG2-mediated, we will overexpress SerpinB2 in TG2-deficient macrophages and use specific TG2 inhibitors.

项目概要/摘要： 纤溶酶原激活物抑制剂1型（派-1）和2型（派-2）是组织的丝氨酸蛋白酶抑制剂， 纤溶酶原激活剂和尿激酶。由SerpinB 2编码的派-2已被证明对 不同疾病的发病机制，包括癌症和线虫感染。然而，它在肥胖中的作用- 相关的胰岛素抗性是未知的。我们的初步实验显示糖尿病患者 与非糖尿病患者相比， 个体此外，我们观察到SerpinB 2+细胞的频率与身体 患者的体重指数，表明SerpinB 2在糖尿病中的保护作用。一致，SerpinB 2缺陷 小鼠表现出葡萄糖耐量受损。在内脏脂肪组织（VAT）的所有造血细胞中， 驻留巨噬细胞表达可检测的和高量的SerpinB 2。这个巨噬细胞亚群 与瘦对照相比，肥胖的人和小鼠中SerpinB 2的表达显著降低。此外，委员会认为， 肥胖的人类和小鼠的VAT含有减少的驻留巨噬细胞数量，这是由于它们的高 细胞凋亡，这与SerpinB 2众所周知的抗细胞凋亡作用一致。此外，我们发现， SerpinB 2是VAT居民产生抗炎细胞因子如IL-4和IL-13所必需的 巨噬细胞这些细胞因子对于维持胰岛素敏感性至关重要。根据这些观察，我们 假设肥胖症中SerpinB 2表达减少触发VAT驻留巨噬细胞凋亡， 增加炎症和促进胰岛素抵抗。我们将在两个具体目标中检验这一假设。瞄准 1.为了确定SerpinB 2在胰岛素抵抗中的作用，我们将使用3种方法：a）SerpinB 2-/-小鼠，B） 巨噬细胞特异性SerpinB 2缺陷小鼠（LysMcre/+ SerpinB 2fl/fl）和c）VAT中的SerpinB 2沉默 使用配制在类胡萝卜素纳米颗粒中的siRNA在野生型小鼠中体内对巨噬细胞进行的细胞毒性试验。此外，我们将 确定肥胖中T细胞来源的IFN-γ是否降低SerpinB 2表达。我们还将测试SerpinB 2是否- 抗炎细胞因子的介导产生依赖于Kruppel样因子4（Klf 4）和有丝分裂原 活化的蛋白激酶（MAPK）激活剂ERK 1/2。瞄准2.我们将研究 SerpinB 2对细胞凋亡的抑制作用。我们的初步数据表明，SerpinB 2缺陷 巨噬细胞含有降低水平的转氨酶2（TG 2），一种已知的半胱天冬酶调节剂。 此外，我们观察到SerpinB 2直接结合TG 2。确定SerpinB 2的抗凋亡作用是否 是TG 2介导的，我们将在TG 2缺陷的巨噬细胞中过表达SerpinB 2并使用特异性TG 2抑制剂。