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（PARP 1）是一种多结构域蛋白，其含有催化和其它功能。 结构域，其中一些涉及DNA结合和与其他分子的相互作用。进行催化 通过将多个ADP-核糖单元从NAD+转移到 受体蛋白，翻译后修饰称为PAR化。PARP 1在凋亡过程中被切割， 但对于细胞死亡不是必需的，因为表达不可切割PARP 1的小鼠与缺乏PARP 1的小鼠一样正常发育。 这种蛋白质。我们发现，敲入小鼠整体表达不可切割的PARP 1突变体（组成型 活性突变体）由于降低的OC分化和骨吸收而表现出高骨量表型， 而骨形成不受影响。相反，小鼠中Parp 1的生殖细胞消融导致骨质减少 源于破骨细胞生成增加，而骨生成未改变。因此，PARP 1功能获得性 突变阻碍破骨细胞生成，而功能丧失促进这一过程。从机制上讲，我们发现 PARP 1在OC前体中高度表达，并在OC分化过程中降解， 主OC转录因子NFATc 1在破骨细胞生成期间被PARylated，意味着翻译后 PARP 1的规则。我们还发现PARP 1抑制OC的全局阻遏物的表达， 抑制器Blimp 1有趣的是，虽然PARP 1酶活性的抑制剂增强了OC的形成， 在M-CSF和RANKL存在下培养的小鼠骨髓巨噬细胞，在体外表达 缺乏催化结构域的PARP 1突变体抑制破骨细胞生成。这些观察提示 PARP 1通过PAR化和其他不需要其催化活性的机制抑制OC分化。 然而，PARP 1复合物对破骨细胞生成的调节作用的相对作用尚不清楚。的 这一建议的中心假设是PARP 1通过PAR化依赖性抑制骨吸收， 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PARP 1的骨骼作用。目的2：明确PARP 1调控的机制， 破骨细胞生成这项工作将确定PARP 1在调节骨的生理重要性。 内稳态及其作用机制。因此，这项提议将在骨重建方面开辟新天地， 专注于OC监管的新玩家。了解PARP 1在骨重建中的作用将有助于阐明 未被认识到的，一类新药的潜在副作用，并确定一个可能的新的研究途径， 以抑制骨吸收为目的的治疗开发。