Role of gasdermin D in bone resorption

Gasdermin D 在骨吸收中的作用

• 批准号: 10094198
• 负责人: Gabriel Mbalaviele
• 金额: $ 37.48万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-15 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10094198
• 关键词: Ablation; Adverse effects; Alcohol dependence; Biochemical; Bone Marrow Transplantation; Bone Resorption; Bone remodeling; Cell Death; Cell membrane; Cells; Chemotherapy and/or radiation; Chronic; Clinical; Data; Development; Disease; Disulfiram; Dose; Environment; FDA approved; Fracture; Functional disorder; Genetic; Hematologic Neoplasms; Immune; Immune response; In Vitro; Inflammasome; Inflammation; Inflammatory; Interleukin-1; Interleukin-1 beta; Interleukin-18; Knockout Mice; Lipopolysaccharides; Membrane; Mus; Mutate; Osteoclasts; Osteogenesis; Osteolysis; Participant; Pathologic; Pathology; Periodicity; Pharmacology; Pharmacotherapy; Play; Procedures; Process; Production; Proteins; Radiation; Radiation therapy; Rare Diseases; Regimen; Research; Role; Rupture; Septic Shock; Signal Transduction; Structure; Syndrome; Testing; Transplant Recipients; VDAC1 gene; autoinflammatory; bone; bone loss; bone mass; bone turnover; cancer cell; chemotherapy; conditioning; cytokine; drug discovery; extracellular; inflammatory bone loss; loss of function; mouse model; prevent; radioresistant; recruit; response; skeletal; tissue repair

The study of rare diseases often informs more common pathologies. We have extensively studied the NLRP3 inflammasome, which is mutated in autoinflammatory disorders such as cryopyrin-associated periodic syndromes (CAPS). A major feature of these conditions is excessive production of IL-1β, which is also highly induced by procedures such as radiotherapy and chemotherapy, commonly used to kill malignant cells or as a conditioning regimen for bone marrow transplantation (BMT). IL-1β potently promotes bone resorption while simultaneously inhibiting bone formation, but IL-1 blocking agents have limited efficacy in the treatment of syndrome-associated bone pathologies. This suggests that other actions of the inflammasomes beyond IL-1β processing, contribute to adverse skeletal effects in diseases. The inflammasomes are responsible for the maturation of IL-1β and IL-18. Recent studies have identified GSDMD as an additional critical substrate of the inflammasomes. Activated GSDMD translocates to the plasma membrane where it forms pores through which IL-1β and IL-18 are secreted. However, excessive pore formation compromises membrane integrity, releasing pro-inflammatory cytoplasmic contents into the extracellular environment. This form of cell death, termed pyroptosis is inflammatory. Thus, while GSDMD is a normal participant in immune responses and tissue repair, its chronic activation promotes inflammation. We surmise that the concomitant release of multiple inflammatory factors during pyroptosis causes pathological bone loss. Therefore, inhibition of GSDMD could provide superior efficacy over IL-1 blockade, not only in the context of CAPS, but also radiation and chemotherapy. Recent drug discovery efforts have identified disulfiram as an antagonist of GSDMD-pore forming activity. Disulfiram is an FDA-approved drug for the treatment of alcohol addiction. We found that administration of disulfiram to mice inhibited LPS-stimulated IL-1β production. Disulfiram also inhibited IL-1β secretion, pyroptosis and osteoclast (OC) differentiation in vitro. To further study the role of GSDMD in bone resorption, we determined skeletal impact of GSDMD loss-of-function in mouse models. Preliminary results indicate that baseline bone mass was higher in Gsdmd-/- compared to WT mice. Moreover, the exuberant OC formation that occurred in CAPS mice was normalized upon Gsdmd ablation. Gsdmd null mice were also resistant to radiation/BMT-induced bone loss. In vitro data further demonstrated that expression of GSDMD was up- regulated during OC differentiation, and genetic ablation of this protein decreased OC formation. These results suggest that GSDMD is functional in OC without compromising their survival, and regulates bone resorption. The central hypothesis of this proposal is that GSDMD regulates bone resorption in pathological conditions through mechanisms involving its actions in inflammatory cells and OC lineage. We will test this hypothesis in two Aims: Aim 1: Determine the role of GSDMD in bone resorption in pathological conditions. Aim 2: Define the role of GSDMD in the OC lineage and elucidate the mechanisms of its activation in these cells.

对罕见疾病的研究通常可以揭示更常见的病理情况。我们广泛研究了 NLRP3 炎症小体，在自身炎症性疾病中发生突变，例如冷吡蛋白相关周期性 综合症（CAPS）。这些病症的一个主要特征是 IL-1β 的过度产生，这也是高度 由放疗和化疗等程序引起，通常用于杀死恶性细胞或作为 骨髓移植（BMT）的预处理方案。 IL-1β 有效促进骨吸收，同时 同时抑制骨形成，但 IL-1 阻断剂在治疗骨形成方面效果有限 综合征相关的骨病理。这表明炎症小体除了 IL-1β 之外还具有其他作用 加工，会导致疾病中对骨骼的不利影响。炎症小体负责 IL-1β 和 IL-18 的成熟。最近的研究已确定 GSDMD 是一个额外的关键底物 炎症小体。激活的 GSDMD 转移到质膜，在那里形成孔，通过这些孔 分泌 IL-1β 和 IL-18。然而，过度的孔形成会损害膜的完整性，释放 促炎细胞质内容物进入细胞外环境。这种形式的细胞死亡，称为 焦亡是炎症性的。因此，虽然 GSDMD 是免疫反应和组织修复的正常参与者， 它的慢性激活会促进炎症。我们推测多种炎症的同时释放 焦亡过程中的因素会导致病理性骨质流失。因此，抑制 GSDMD 可以提供 不仅在 CAPS 方面，而且在放疗和化疗方面，其疗效均优于 IL-1 阻断。 最近的药物发现工作已确定双硫仑是 GSDMD 孔形成活性的拮抗剂。 双硫仑是 FDA 批准的用于治疗酒精成瘾的药物。我们发现，管理 双硫仑对小鼠抑制 LPS 刺激的 IL-1β 产生。双硫仑还抑制 IL-1β 分泌， 体外焦亡和破骨细胞（OC）分化。为了进一步研究GSDMD在骨吸收中的作用， 我们在小鼠模型中确定了 GSDMD 功能丧失对骨骼的影响。初步结果表明 与 WT 小鼠相比，Gsdmd-/- 的基线骨量更高。此外，旺盛的 OC 形成 CAPS 小鼠中发生的情况在 Gsdmd 消融后正常化。 Gsdmd 缺失小鼠也对 辐射/BMT 引起的骨质流失。体外数据进一步表明 GSDMD 的表达上调 在 OC 分化过程中受到调节，并且该蛋白的基因消除减少了 OC 的形成。这些结果 表明 GSDMD 在 OC 中发挥作用而不影响其生存，并调节骨吸收。 该提案的中心假设是 GSDMD 在病理条件下调节骨吸收 通过涉及其在炎症细胞和 OC 谱系中的作用的机制。我们将在 两个目标： 目标 1：确定 GSDMD 在病理条件下骨吸收中的作用。目标 2：定义 GSDMD 在 OC 谱系中的作用并阐明其在这些细胞中的激活机制。