SHIP1 REGULATION OF DAP12 IN OSTEOCLAST DEVELOPMENT AND FUNCTION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 破骨细胞在自身免疫性疾病状态下被不适当地激活，如类风湿性关节炎。虽然破骨细胞分化需要通过RANKL和MCSF的信号，但其他受体的调节作用还不是很清楚。我们关注的是TREM2，破骨细胞中发现的一种免疫受体。TREM2与DAP12结合，DAP12是一种含有信号转接子蛋白的免疫受体酪氨酸激活基序。TREM2/DAP12信号通路是破骨细胞成熟所必需的，并在体外激活破骨细胞的融合和迁移。细胞内磷酸酶负向调节造血细胞中的许多ITAM接头蛋白。因此，我们研究了磷酸酶抑制破骨细胞中TREM2/DAP12信号的作用。我们的数据表明，破骨细胞裂解物中含有SH2结构域的5‘-肌醇磷酸酶(SHIP1)和DAP12是相关的。在破骨细胞形成过程中，SHIP1缺失的破骨前细胞对TREM2/DAP12信号反应强烈，表明SHIP1在抑制这一途径中具有功能作用。这些数据表明SHIP1磷酸酶调节破骨细胞中的DAP12信号。利用C57BL6和SHIP1-/-小鼠的原代破骨细胞培养的体外破骨细胞生成实验，我们正在确定SHIP1在调节DAP12信号中的作用。我们正在绘制DAP12和SHIP1之间的蛋白质-蛋白质相互作用图谱。我们正在确定SHIP1是否在包括M-CSF和骨桥蛋白在内的其他刺激下调节DAP12的激活。这些研究将揭示SHIP1调控DAP12信号的功能性质以及破骨细胞中这一调控所需的重要蛋白结构域，并可能导致抑制破骨细胞分化或激活的新策略。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Osteoclasts are inappropriately activated in autoimmune disease states such as rheumatoid arthritis. While signals through RANKL and MCSF are required for osteoclast differentiation, regulation by other receptors is less well defined. We have focused on TREM2, an immune receptor found in osteoclasts. TREM2 associates with DAP12, an ITAM (immunoreceptor tyrosine-based activation motif) containing signaling adapter protein. TREM2/DAP12 signaling is required for osteoclast maturation and activates osteoclast fusion and migration in vitro. Intracellular phosphatases negatively regulate many ITAM adapter proteins in hematopoietic cells. As such, we investigated the role of phosphatases inhibiting TREM2/DAP12 signals in osteoclasts. Our data shows that SH2 domain-containing 5' inositol phosphatase (SHIP1) and DAP12 are associated in osteoclast cell lysates. SHIP1 null preosteoclasts are hyper-responsive to TREM2/DAP12 signaling during osteoclastogenesis indicating that SHIP1 has a functional role in inhibiting this pathway. These data suggest that SHIP1 phosphatase regulates DAP12 signaling in osteoclasts. Using in vitro osteoclastogenesis assays from primary murine osteoclast cultures from C57Bl6 and SHIP1-/- mice we are determining the role of SHIP1 in regulating DAP12 signals. We are mapping the protein-protein interactions between DAP12 and SHIP1. We are determining whether SHIP1 regulates DAP12 activation in response to other stimuli including M-CSF and osteopontin. These studies will reveal the functional nature of SHIP1 regulation of DAP12 signaling as well as the important protein domains required for this regulation in osteoclasts and might lead to novel strategies to inhibit osteoclast differentiation or activation.