Role of gasdermin D in bone resorption

Gasdermin D 在骨吸收中的作用

• 批准号: 10335233
• 负责人: Gabriel Mbalaviele
• 金额: $ 37.61万
• 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/10335233
• 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; Syndrome; Testing; Transplant Recipients; VDAC1 gene; antagonist; 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.

对罕见疾病的研究往往会揭示出更常见的病理学。我们对NLRP3进行了广泛的研究 炎性小体，在自身炎症性疾病中突变，如低温比林相关的周期性 综合征(CAPS)。这些情况的一个主要特征是IL-1β的过度产生，这也是高度 由放疗和化疗等程序诱导的，通常用于杀死恶性细胞或作为一种 骨髓移植(BMT)的调节方案。IL-1β可有效促进骨吸收 同时抑制骨形成，但IL-1阻滞剂治疗骨质疏松症疗效有限 症候群相关的骨骼病理。这表明炎性小体的其他作用超出了IL-1β 加工，有助于在疾病中对骨骼产生不利影响。炎性小体是导致 IL-1β和IL-18的成熟。最近的研究发现，GSDMD是一种额外的关键底物 炎症性小体。活化的GSDMD转移到质膜上，在那里形成孔，通过 分泌IL-1、β和IL-18。然而，过多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 上睑下垂是炎症性的。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，伴随而来的多种炎症的释放 上睑下垂时的各种因素会导致病理性骨丢失。因此，抑制GSDMD可以提供 不仅在CAPS的背景下，而且在放射和化疗方面，其疗效优于IL-1阻断。 最近的药物发现工作已经确定双硫兰是GSDMD-孔道形成活性的拮抗剂。 双硫兰是FDA批准的治疗酒精成瘾的药物。我们发现，政府对 双硫兰可抑制脂多糖刺激的IL-1β的产生。双硫兰还抑制IL-1β的分泌， 上睑下垂与破骨细胞(OC)体外分化。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-/-组的基线骨量更高。此外，旺盛的OC形成 在Gsdmd消融后，CAPS小鼠的脑电活动恢复正常。Gsdmd缺失的小鼠也对 辐射/骨髓移植所致的骨丢失。体外实验进一步证明GSDMD的表达上调。 在OC分化过程中受到调节，该蛋白的基因消融减少了OC的形成。这些结果 提示GSDMD在OC中起作用而不影响其生存，并调节骨吸收。 这一建议的中心假设是GSDMD在病理条件下调节骨吸收 通过其在炎性细胞和OC谱系中的作用机制。我们将在以下方面测试这一假设 目的1：确定病理条件下GSDMD在骨吸收中的作用。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。