Role of PARP1 in the Osteoclast Lineage

PARP1 在破骨细胞谱系中的作用

• 批准号: 9172924
• 负责人: Gabriel Mbalaviele
• 金额: $ 33.09万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9172924
• 关键词: Ablation; Adenosine Diphosphate Ribose; Adverse effects; Apoptosis; B lymphocyte-induced maturation protein 1; Bone Marrow; Bone Resorption; Bone remodeling; Catalytic Domain; Cell Death; Cells; Cleaved cell; Complex; DNA Binding; Data; Development; Disease; Energy Metabolism; Exhibits; Genetic; Genetic Transcription; Goals; Homeostasis; In Vitro; Knock-in Mouse; Lead; Light; Macrophage Colony-Stimulating Factor; Mus; Mutant Strains Mice; Myeloid Cells; Names; Nicotinamide adenine dinucleotide; Osteoclasts; Osteogenesis; Osteopenia; Pharmaceutical Preparations; Phenotype; Physiological; Play; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerases; Polymers; Post-Translational Protein Processing; Post-Translational Regulation; Process; Proteins; Regulation; Research; Role; Signal Transduction; Structure-Activity Relationship; TNFSF11 gene; Tertiary Protein Structure; Testing; Work; bone; bone loss; bone mass; cancer therapy; clinical practice; epigenetic regulation; gain of function mutation; in vivo; inhibitor/antagonist; loss of function; macrophage; mutant; nuclear factors of activated T-cells; osteoclastogenesis; prevent; prospective; skeletal; stem; therapeutic development; transcription factor

Poly(ADP-ribose) polymerase 1 (PARP1) is a multi-domain protein containing a catalytic and other domains, some of which are involved in DNA binding and interaction with other molecules. It catalyzes the formation of poly-ADP-ribose (PAR) polymers by transferring multiple ADP-ribose units from NAD+ onto acceptor proteins, a post-translational modification termed PARylation. PARP1 is cleaved during apoptosis, but is not essential for cell death as mice expressing uncleavable PARP1 develop normally as do mice lacking this protein. We find that knock-in mice globally expressing a non-cleavable PARP1 mutant (constitutively active mutant) exhibit a high bone mass phenotype owing to decreased OC differentiation and bone resorption, while bone formation is unaffected. Conversely, germline ablation of Parp1 in mice causes osteopenia stemming from increased osteoclastogenesis, while osteogenesis is unaltered. Thus, PARP1 gain-of-function mutation hinders osteoclastogenesis whereas loss-of-function promotes this process. Mechanistically, we find that PARP1 is highly expressed by OC precursors and it is degraded during OC differentiation, and that the master OC transcription factor, NFATc1, is PARylated during osteoclastogenesis, implying post-translational regulation by PARP1. We also find that PARP1 inhibits the expression of the global repressor of OC suppressors, Blimp1. Intriguingly, while an inhibitor of PARP1 enzymatic activity enhances OC formation from mouse bone marrow macrophages cultured in the presence of M-CSF and RANKL, in vitro expression of a PARP1 mutant lacking the catalytic domain inhibits osteoclastogenesis. These observations suggest that PARP1 inhibits OC differentiation via both PARylation and other mechanisms not requiring its catalytic activity. However, the relative roles of PARP1 complex regulatory effects on osteoclastogenesis are unknown. The central hypothesis of this proposal is that PARP1 inhibits bone resorption via PARylation -dependent and - independent antagonism of osteoclastogenesis. We will test this hypothesis in the following two aims. Aim 1: Determine the skeletal actions of PARP1. Aim 2: Define the mechanisms of PARP1 regulation of osteoclastogenesis. The proposed work will determine PARP1 physiologic importance in modulating bone homeostasis, and its mechanism of action. Therefore, this proposal will break new ground on bone remodeling, focusing on a new player in OC regulation. Understanding PARP1 role in bone remodeling will clarify unrecognized, potential side effects of a new class of drugs and define a possible new avenue of research for therapeutic development with the purpose of inhibiting bone resorption.

聚（ADP-核糖）聚合酶1（PARP1）是一种多域蛋白，含有催化和其他 域，其中一些涉及DNA结合并与其他分子相互作用。它催化了 通过将多个ADP-核糖单元从NAD+转移到上 受体蛋白，一种翻译后的修饰称为pary蛋白。 PARP1在凋亡过程中裂解， 但是对于细胞死亡而言并不是必不可少的，因为表达不可释放的PARP1的小鼠正常发展 该蛋白质。我们发现全球表达不可裂解的PARP1突变体的敲击小鼠（组成型 活性突变体）由于OC分化和骨吸收减少而表现出高骨质量表型 而骨骼形成不受影响。相反，小鼠的生殖器消融parp1会导致骨质减少 造成破骨细胞生成的增加，而成骨的发生是没有改变的。因此，PARP1功能获得 突变阻碍破骨细胞生成，而功能丧失促进了这一过程。从机械上讲，我们发现 该PARP1由OC前体高度表达，并且在OC分化过程中会降解，并且 主OC转录因子NFATC1在破骨细胞生成期间被释放，这意味着翻译后 通过PARP1进行调节。我们还发现PARP1抑制了OC的全球阻遏物的表达 抑制器，Blimp1。有趣的是，尽管PARP1酶促活性的抑制剂可增强OC的形成 小鼠骨髓巨噬细胞在M-CSF和RANKL存在下培养 缺乏催化结构域的PARP1突变体抑制破骨细胞生成。这些观察表明 PARP1通过荷载和其他不需要其催化活性的机制抑制OC分化。 然而，PARP1复杂调节对破骨细胞发生的相对作用尚不清楚。这 该提议的中心假设是PARP1通过依赖性和 - 抑制骨吸收 破骨细胞生成的独立拮抗作用。我们将在以下两个目标中检验这一假设。目标1： 确定PARP1的骨骼作用。目标2：定义PARP1调节的机制 破骨细胞生成。拟议的工作将确定PARP1生理重要性在调节骨骼中 稳态及其作用机理。因此，该提案将在骨骼重塑上打破新的地面， 专注于OC法规中的新玩家。了解PARP1在骨骼重塑中的作用将澄清 一类新药物的未识别，潜在的副作用，并定义了可能的新研究途径 治疗性发育是为了抑制骨吸收。