Regulation of osteoclast biology by anion exchanger SLC4A2 in mouse and human sys

阴离子交换剂 SLC4A2 在小鼠和人类系统中对破骨细胞生物学的调节

• 批准号: 8183325
• 负责人: ANTONIOS O ALIPRANTIS
• 金额: $ 12.63万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2012-06-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8183325
• 关键词: Acids; Actins; Adult; Affect; Age; Albers-Schonberg disease; Alkalinization; American; Anions; Apoptosis; Area; Bicarbonates; Biology; Bone Diseases; Bone Marrow; Bone Resorption; Bone Surface; Bone remodeling; Boston; Calcified; Cattle; Cells; Cellular biology; Chloride Ion; Chlorides; Collaborations; Complex; Cytokine Receptors; Cytoplasm; Cytoplasmic Tail; Cytoskeleton; Data; Defect; Development; Disease; Drug Kinetics; Environment; Enzymes; Family; Genes; Giant Cells; Grant; Health; Health Care Costs; Human; Hydrochloric Acid; Inequality; Inflammatory; Ions; Knockout Mice; Ligands; Medical; Metastatic Neoplasm to the Bone; Minerals; Mus; Mutation; Myelogenous; N-terminal; Osteitis; Osteoblasts; Osteoclasts; Osteolysis; Osteoporosis; Pathogenesis; Pathologic; Peptide Hydrolases; Pharmaceutical Preparations; Phase; Phenotype; Physiology; Play; Population; Process; Publications; Publishing; RNA Interference; Regulation; Relative (related person); Reporting; Research Personnel; Rheumatoid Arthritis; Role; Signal Transduction; Skeleton; Staging; Stress; Structure; TNFSF11 gene; Tissues; Transmembrane Domain; Work; apical membrane; base; basolateral membrane; bone; bone health; bone loss; bone mass; burden of illness; cell type; gene function; in vivo; member; mouse model; novel; osteoporosis with pathological fracture; postnatal; prevent; seal; skeletal; skeletal abnormality; skeletal disorder; solute; therapeutic target

DESCRIPTION (provided by applicant): Bone is a dynamic tissue that remodels to grow, adapt to stress and maintain integrity. Two cell types control this process, the osteoblast (OB) and the osteoclast (OC), which synthesize and degrade bone, respectively. Pathologic inequality in bone remodeling favoring resorption over formation leads to diseases such as osteoporosis, rheumatoid arthritis and metastatic bone cancer. Currently, over 30 million Americans have low bone mass and nearly 1% of our population suffers from rheumatoid arthritis. The yearly health care cost burden of these diseases is immense. Currently approved therapeutics targeting OCs are inadequate, necessitating the discovery of new targets. To resorb bone, osteoclasts secrete hydrochloric acid. To prevent a reciprocal build up of cytoplasmic base, electroneutral exchange of bicarbonate for chloride occurs through an anion exchanger. The identity of this exchanger eluded identification until our recent report showing Solute carrier family 4, anion exchanger, member 2 (Slc4a2, Ae2) is absolutely required for osteoclast activity during development. In its absence, mice develop profound osteopetrosis. A recent publication has identified a nearly identical phenotype in cattle that lack SLC4A2. To date, only a handful of mutations have been identified that so dramatically curtail the ability of osteoclasts to resorb calcified tissue. Our preliminary data suggest that SCL4A2 plays an unexpected complex role in OC physiology. We have found that SLC4A2 deficiency not only prevents OCs from properly secreting acid and performing anion exchange, but also profoundly affects the organization of their cytoskeleton. Many important questions remain regarding the biology of SLC4A2 in the OC. We do not know whether SLC4A2 is important in bone remodeling beyond the developmental period or in the pathogenesis of inflammatory skeletal disease. The relative contribution of the cytoplasmic and transmembrane domains of SLC4A2 to the regulation of osteoclast biology is unknown. Moreover, whether human osteoclasts utilize SLC4A2 is undefined. Four specific aims are proposed to answer these questions: 1) Establish the OC-intrinsic role of SLC4A2 and resolve the contribution of osteopetrosis to the lethal phenotype of Slc4a2-/- mice; 2) Establish the requirement of SLC4A2 in a mouse model of inflammatory arthritis; 3) Perform a structure-function analysis of SLC4A2 in OCs and 4) Confirm a role for SLC4A2 in human OCs. I will take advantage of the unique environment in Boston to facilitate these studies. Collaborations have been established with local experts in anion exchange physiology, OC cell biology, mouse models of RA and RNA interference. By analyzing the function of a gene that so profoundly affects OC biology, this grant will advance basic understanding of skeletal remodeling, make important contributions to general cell biology and signal transduction and, most importantly, define a new target to suppress pathologic bone loss. PUBLIC HEALTH RELEVANCE: Dynamic remodeling of bone allows our skeleton to grow and adapt to stress, but makes it susceptible to diseases such as osteoporosis and rheumatoid arthritis. The only cell capable of destroying bone is the osteoclast, a multinucleated giant cell that secretes hydrochloric acid and proteolytic enzymes. This grant aims to better understand how osteoclasts work by probing the function of an ion exchanger (SLC4A2) that osteoclasts require to perform this remarkable, but often pathologic, feat.

描述（由申请人提供）：骨骼是一种动态组织，可以通过重塑来生长、适应压力并保持完整性。有两种细胞类型控制这一过程，即成骨细胞 (OB) 和破骨细胞 (OC)，它们分别合成和降解骨。骨重塑的病理不平等有利于吸收而不是形成，导致骨质疏松症、类风湿性关节炎和转移性骨癌等疾病。目前，超过 3000 万美国人骨质疏松，近 1% 的美国人患有类风湿性关节炎。这些疾病每年造成的医疗费用负担是巨大的。目前批准的针对 OC 的治疗方法还不够，需要发现新的靶点。为了吸收骨质，破骨细胞分泌盐酸。为了防止细胞质碱基的相互积累，通过阴离子交换剂发生碳酸氢盐与氯离子的电中性交换。这种交换剂的身份一直未能被识别，直到我们最近的报告显示溶质载体家族 4，阴离子交换剂，成员 2（Slc4a2，Ae2）对于破骨细胞发育过程中的活性绝对是必需的。如果没有它，小鼠就会出现严重的石骨症。最近的一篇文章在缺乏 SLC4A2 的牛身上发现了几乎相同的表型。迄今为止，仅发现了少数突变，这些突变极大地削弱了破骨细胞吸收钙化组织的能力。我们的初步数据表明 SCL4A2 在 OC 生理学中发挥着意想不到的复杂作用。我们发现，SLC4A2 缺陷不仅会阻止 OC 正常分泌酸和进行阴离子交换，还会深刻影响其细胞骨架的组织。关于 OC 中 SLC4A2 的生物学特性，仍然存在许多重要问题。我们不知道 SLC4A2 在发育期之后的骨重塑或炎症性骨骼疾病的发病机制中是否重要。 SLC4A2 的细胞质和跨膜结构域对破骨细胞生物学调节的相对贡献尚不清楚。此外，人类破骨细胞是否利用SLC4A2尚不清楚。提出了四个具体目标来回答这些问题：1）建立SLC4A2的OC内在作用并解决骨硬化对Slc4a2-/-小鼠致死表型的影响； 2) 建立炎症性关节炎小鼠模型中SLC4A2的需求； 3) 对 OC 中的 SLC4A2 进行结构功能分析，4) 确认 SLC4A2 在人类 OC 中的作用。我将利用波士顿独特的环境来促进这些研究。我们与阴离子交换生理学、OC 细胞生物学、RA 小鼠模型和 RNA 干扰方面的当地专家建立了合作。通过分析对 OC 生物学产生如此深远影响的基因的功能，这笔资助将增进对骨骼重塑的基本了解，为一般细胞生物学和信号转导做出重要贡献，最重要的是，确定抑制病理性骨质流失的新靶点。 公共健康相关性：骨骼的动态重塑使我们的骨骼能够生长并适应压力，但也使其容易患骨质疏松症和类风湿性关节炎等疾病。唯一能够破坏骨骼的细胞是破骨细胞，这是一种分泌盐酸和蛋白水解酶的多核巨细胞。这项资助旨在通过探测破骨细胞执行这一非凡但通常是病理性的壮举所需的离子交换剂 (SLC4A2) 的功能，更好地了解破骨细胞的工作原理。