Mechanism of ITAM Signal Regulation in Osteoclasts

破骨细胞ITAM信号调控机制

• 批准号: 7906881
• 负责人: Mary Beth Humphrey
• 金额: $ 25.46万
• 依托单位: UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-10 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7906881
• 关键词: Actins; Acute; Affect; Alveolar Bone Loss; Antibodies; Bacteria; Biological Assay; Bone Resorption; Bone remodeling; Cells; Chimeric Proteins; Chronic; DNA polymerase epsilon stimulatory factor 1; Data; Deposition; Development; Disease; Dose; Equilibrium; Exhibits; Goals; Human; ITAM; IgE Receptors; Immune; In Vitro; Inflammation; Inflammatory; Integrins; Lead; Life; Ligands; Lipids; Mediating; Mission; Mus; Myelogenous; Myeloid Cells; Osteoblasts; Osteoclasts; Osteopenia; Osteoporosis; Pathway interactions; Periodontal Diseases; Periodontitis; Phosphoric Monoester Hydrolases; Phosphotransferases; Porphyromonas gingivalis; Protein Tyrosine Kinase; Protein Tyrosine Phosphatase; Proteins; Regulation; Regulatory Pathway; Role; Signal Pathway; Signal Transduction; TNFSF11 gene; TYROBP gene; Therapeutic Intervention; adapter protein; base; bone; human disease; in vivo; inositol-1,4,5-trisphosphate 5-phosphatase; insight; macrophage; migration; myo-inositol-1 (or 4)-monophosphatase; novel; novel therapeutic intervention; osteoclastogenesis; receptor; response; src Homology Region 2 Domain; triggering receptor expressed on myeloid cells 2 protein, human

DESCRIPTION (provided by applicant): Bone integrity is maintained via the careful balance of bone deposition by osteoblasts and bone resorption by osteoclasts (OC). Bone remodeling occurs throughout life and imbalances in formation and resorption lead to human diseases including osteoporosis and periodontitis, a mission of the agency. We are studying the negative regulation of ITAM-adapter signals in osteoclasts. Specifically we are investigating the possibility that phosphatases may regulate ITAM-adapter, DAP12, signaling. We have found a novel association of activated DAP12 with SH2-containing inositol-5'-phosphatase 1 (SHIP1). Our central hypothesis is that SHIP1 regulates DAP12 signaling during OC development and function in vitro and in vivo. Specific Aim 1: Determine the mechanism by which SHIP1 inhibits DAP12 signaling. These studies aim to determine the functional domains of SHIP1 that are required for inhibition of DAP12 signaling, the role of proximal kinases, and the specific downstream signaling pathways negatively regulated by SHIP1. We will determine the role of SHIP1 in negatively regulating DAP12 downstream of MCSF, RANKL, and integrin stimulation. We will investigate the specific role of DAP12-associated receptors in mediating SHIP1- DAP12 association. Specific Aim 2: Determine how SHIP1 inhibition of DAP12 signaling affects the OC functions of resorption, actin ring formation and survival in vitro. We will determine the cellular localization of SHIP1 and DAP12 during DAP12 stimulation. Specific Aim 3: Determine the affect of SHIP1 on DAP12 signaling in vivo. We will determine whether SHIP1 regulates DAP12 signaling in vivo after direct activation of DAP12 with anti-TREM2 antibodies or blockade of DAP12 with TREM2-fusion protein. Specific Aim 4: Determine the role of SHIP1 and TREM2/DAP12 in response to Porphyromonas gingivalis (P. gingivalis) induced alveolar bone loss. Additionally we will investigate the roles of DAP12 and SHIP1 in inflammatory trabecular and alveolar bone loss induced by chronic low dose LPS treatment or acute stimulation with P. gingivalis LPS in vivo. These studies will not only elucidate how SHIP1 regulates DAP12 signaling in OC but will potentially give insights into how DAP12 can function as both an activating and inhibitory signal in macrophages and OC. This understanding might lead to novel therapeutic interventions in periodontal disease and osteoporosis. Project Narrative: The aim of proposed studies is to define a key regulatory pathway needed to inhibit activity of osteoclasts, cells that dissolve bone. This understanding might lead to novel therapeutic interventions in chronic periodontal disease and osteoporosis, diseases associated with excessive osteoclast activity.

描述（由申请人提供）：通过成骨细胞的骨沉积和破骨细胞（OC）的骨吸收的仔细平衡来维持骨完整性。骨骼重塑贯穿一生，形成和吸收的不平衡会导致骨质疏松症和牙周炎等人类疾病，这是该机构的使命。我们正在研究破骨细胞中 ITAM 适配器信号的负调节。具体来说，我们正在研究磷酸酶可能调节 ITAM 适配器、DAP12 信号传导的可能性。我们发现激活的 DAP12 与含有 SH2 的肌醇 5'-磷酸酶 1 (SHIP1) 存在新的关联。我们的中心假设是 SHIP1 在 OC 发育和体外和体内功能过程中调节 DAP12 信号传导。具体目标 1：确定 SHIP1 抑制 DAP12 信号传导的机制。这些研究旨在确定抑制 DAP12 信号传导所需的 SHIP1 功能域、近端激酶的作用以及 SHIP1 负向调节的特定下游信号传导途径。我们将确定 SHIP1 在负调节 MCSF、RANKL 和整合素刺激下游的 DAP12 中的作用。我们将研究 DAP12 相关受体在介导 SHIP1-DAP12 关联中的具体作用。具体目标 2：确定 SHIP1 对 DAP12 信号传导的抑制如何影响 OC 的吸收、肌动蛋白环形成和体外存活功能。我们将确定 DAP12 刺激期间 SHIP1 和 DAP12 的细胞定位。具体目标 3：确定 SHIP1 对体内 DAP12 信号传导的影响。我们将在用抗TREM2抗体直接激活DAP12或用TREM2融合蛋白阻断DAP12后确定SHIP1是否在体内调节DAP12信号传导。具体目标 4：确定 SHIP1 和 TREM2/DAP12 在应对牙龈卟啉单胞菌 (P. gingivalis) 诱导的牙槽骨丢失中的作用。此外，我们将研究 DAP12 和 SHIP1 在慢性低剂量 LPS 治疗或体内牙龈卟啉单胞菌 LPS 急性刺激诱导的炎症性小梁和牙槽骨丢失中的作用。这些研究不仅将阐明 SHIP1 如何调节 OC 中的 DAP12 信号传导，而且有可能深入了解 DAP12 如何在巨噬细胞和 OC 中发挥激活和抑制信号的作用。这种理解可能会导致牙周病和骨质疏松症的新治疗干预措施。项目叙述：拟议研究的目的是确定抑制破骨细胞（溶解骨骼的细胞）活性所需的关键调节途径。这种理解可能会导致针对慢性牙周病和骨质疏松症（与破骨细胞过度活性相关的疾病）的新治疗干预措施。