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: 10445110
• 负责人: Partha Dutta
• 金额: $ 43.27万
• 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/10445110
• 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; In Vitro; Individual; Inflammation; Inflammatory; Insulin Resistance; Interferon Gamma Receptor Complex; Interferon Type II; Interleukin-1 beta; Interleukin-13; Interleukin-4; Knowledge; MAPK3 gene; 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; base; cytokine; diabetic patient; drug development; experimental study; glucose tolerance; impaired glucose tolerance; improved; in vivo; inhibitor; insulin sensitivity; insulin tolerance; macrophage; 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.

项目摘要/摘要： 纤溶酶原激活剂抑制剂 1 型 (PAI-1) 和 2 型 (PAI-2) 是组织的丝氨酸蛋白酶抑制剂 纤溶酶原激活剂和由 SerpinB2 编码的尿激酶 PAI-2 已被证明对于 包括癌症和线虫感染在内的不同疾病的发病机制，但其在肥胖中的作用。 相关的胰岛素抵抗尚不清楚，我们的初步实验表明糖尿病患者。 与非糖尿病患者相比，网膜脂肪组织中 SerpinB2+ 细胞的数量显着减少 此外，我们观察到 SerpinB2+ 细胞的频率与身体呈负相关。 患者体重指数，表明 SerpinB2 在糖尿病中具有一致的保护作用。 小鼠的内脏脂肪组织（VAT）中的所有造血细胞表现出葡萄糖耐量受损。 常驻巨噬细胞表达可检测到的大量 SerpinB2。 与瘦对照相比，肥胖人和小鼠的 SerpinB2 表达显着降低。 肥胖人和小鼠的 VAT 中常驻巨噬细胞数量减少，因为它们的高 细胞凋亡，这与 SerpinB2 众所周知的抗细胞凋亡作用一致。 SerpinB2 对于增值税居民产生抗炎细胞因子（例如 IL-4 和 IL-13）至关重要 根据这些观察，这些细胞因子对于维持胰岛素敏感性至关重要。 肥胖中 SerpinB2 表达减少会引发 VAT 驻留巨噬细胞凋亡， 增加炎症并促进胰岛素抵抗，我们将在两个具体目标上检验这一假设。 1. 为了确定 SerpinB2 在胰岛素抵抗中的作用，我们将使用 3 重方法：a) SerpinB2-/- 小鼠，b) 巨噬细胞特异性 SerpinB2 缺陷小鼠 (LysMcre/+ SerpinB2fl/fl) 和 c) VAT 中 SerpinB2 沉默 使用脂质纳米粒子配制的 siRNA 在野生型小鼠体内进行巨噬细胞实验。 确定肥胖中 T 细胞衍生的 IFN-γ 是否会降低 SerpinB2 表达。我们还将测试 SerpinB2- 是否。 介导抗炎细胞因子的产生取决于 Kruppel 样因子 4 (Klf4) 和丝裂原 活化蛋白激酶（MAPK）激活剂ERK1/2。我们将研究其分子机制。 SerpinB2 预防细胞凋亡。我们的初步数据表明 SerpinB2 缺陷。 巨噬细胞中转谷氨酰胺酶 2 (TG2)（一种已知的半胱天冬酶调节剂）水平降低。 此外，我们观察到SerpinB2直接与TG2结合以确定SerpinB2是否具有抗凋亡作用。 如果是 TG2 介导的，我们将在 TG2 缺陷的巨噬细胞中过度表达 SerpinB2，并使用特定的 TG2 抑制剂。