The role of caspase-2 in osteoblast-osteoclast interactions

Caspase-2 在成骨细胞-破骨细胞相互作用中的作用

基本信息

批准号：
8645567
负责人：
Danielle Arden Callaway
金额：
$ 4.77万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-04-01 至 2015-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8645567
关键词：
Affect Age Aging Aging-Related Process Alkaline Phosphatase Antioxidants Apoptosis Apoptotic BMP6 gene Body fat Bone Marrow Bone Marrow Cells Bone Resorption Cell Culture Techniques Cell Death Cells Cessation of life Clinical Clinical Markers Coculture Techniques Communication Conditioned Culture Media Cysteine Protease Data Dentin Development Disease Dose Elderly Glutathione Goals Growth Hair Hepatocyte Homeostasis Human Knock-out Knockout Mice Kyphosis deformity of spine Lead Link Literature Liver Longevity Macrophage Colony-Stimulating Factor Measures Mediating Mesenchymal Stem Cells Mitochondria Modeling Molecular Molecular Target Mus NADP Organism Osteoblasts Osteoclasts Osteogenesis Osteoporosis Oxidative Stress Peptide Hydrolases Play Premature aging syndrome Production Proteins Relative (related person)Respiration Role Signal Transduction Slice Small Interfering RNA Stress System TNFSF11 gene Tumor necrosis factor receptor 11b Urine Wild Type Mouse age related bone bone loss bone morphogenetic protein 6 bone turnover caspase-2 copper zinc superoxide dismutase deoxypyridinoline macrophage male mineralization mouse model osteoclastogenesis oxidation platelet-derived growth factor BB precursor cell prevent public health relevance release factor research study substantia spongiosa trait urinary

项目摘要

DESCRIPTION (provided by applicant): The overall goal of this study is to elucidate the role of the apoptosis-related protease, caspase-2, in male age-dependent osteoporosis. Our lab has demonstrated that mice deficient in caspase-2 not only have decreased maximum life span, but also show features of premature aging compared to age-matched wild-type mice. Examples of aging-related traits seen in caspase-2 deficient mice include impaired hair regrowth ability, decreased body fat content, increased levels of protein oxidation in the liver, and importantly, severe bone loss. Specifically, we found decreased trabecular bone volume, an increased level of the clinical osteoporosis marker, deoxypyridinoline (DPD), in urine, and increased numbers of osteoclasts, cells responsible for bone resorption. These results suggest that caspase-2 deficiency may prevent osteoclast spontaneous apoptosis, which is induced by oxidative stress. Additionally, we did not observe any compensatory increase in bone formation or osteoblast number, an issue also observed in human osteoporosis. Because of these findings, we hypothesize that caspase-2 plays a critical role in osteoclast apoptosis induced by oxidative stress. Furthermore, because the aging process has been linked to increased oxidative stress levels in cells, we hypothesize that capase-2 is critical in mediating apoptosis of aging osteoclasts, leading to inhibition of excess bone resorption. Our first specific aim will determine if caspase-2 normally induces oxidative stress-dependent apoptosis in osteoclasts as the organism ages. We will determine the levels of oxidative stress markers such as reactive oxidative species (ROS), glutathione (GSH), and NADPH in young and old caspase-2 knockout mice and compare them to levels seen in osteoclasts from age-matched wild-type mice. Additionally, we will investigate the role of oxidative stress in inducing spontaneous apoptosis of aging osteoclasts isolated from caspase-2 knockout and wild-type mice. Our second aim involves determining the role of caspase-2 and aging in osteoblast-osteoclast interactions. This will be accomplished by measuring the expression level of different factors that have been shown to affect osteoblastogenesis (Wnt10b, BMP6, and PDGF BB) or osteoclastogenesis (RANKL, OPG, and M-CSF). These factors will be measured from bone marrow cultures, containing osteoblasts and osteoclasts, generated from bone in young and old caspase-2 knockout and wild- type mice. Furthermore, the factor-rich media from the co-culture will be used as a conditioned media to study osteoblastogenesis and osteoclastogenesis in precursor cells. Understanding the function of caspase-2 in age-dependent osteoporosis, on one hand, and showing how changes in osteoblast-osteoclast interactions can lead to severe bone resorption, on the other, will lead to putative identification of molecular targets that may develop into new and valuable anti-osteoporosis therapies. PUBLIC HEALTH RELEVANCE: Osteoporosis is a debilitating disease that causes severe bone loss in the elderly. This study will help elucidate molecular mechanisms underlying cell death of osteoclasts that are involved in bone resorption. Identification of molecular targets regulating cell death of osteoclasts will help facilitate the creation of new strategies to treat osteoporosis.

描述（由申请人提供）：这项研究的总体目标是阐明与凋亡相关的蛋白酶Caspase-2在男性依赖性骨质疏松症中的作用。我们的实验室已经证明，缺乏caspase-2的小鼠不仅降低了最大寿命，而且还显示出与年龄匹配的野生型小鼠相比的过早衰老的特征。在caspase-2缺乏小鼠中看到的与衰老相关的特征的例子包括头发再生能力受损，体内脂肪含量降低，肝脏中蛋白质氧化的水平增加，重要的是严重的骨质流失。具体而言，我们发现小梁骨体积减少，尿液中的临床骨质疏松标志物，脱氧吡啶氨酸（DPD）的水平升高，尿液数量增加，骨细胞数量增加，负责骨吸收的细胞。这些结果表明，caspase-2缺乏症可以预防破骨细胞的自发凋亡，这是由氧化应激诱导的。此外，我们没有观察到骨形成或成骨细胞数的任何补偿性增加，这在人骨质疏松症中也观察到了。由于这些发现，我们假设caspase-2在氧化应激引起的破骨细胞凋亡中起关键作用。此外，由于衰老过程与细胞中氧化应激水平的升高有关，因此我们假设Capase-2对于介导衰老破骨细胞的凋亡至关重要，从而抑制过量的骨骼吸收。我们的第一个具体目的将确定caspase-2是否通常诱导破骨细胞的氧化应激依赖性凋亡，因为有机体年龄。我们将确定氧化应激标志物的水平，例如反应性氧化物种（ROS），谷胱甘肽（GSH）和NADPH，在年轻和老式的caspase-2敲除小鼠中，并将它们与年龄匹配的野生型小鼠的破骨细胞中看到的水平进行比较。此外，我们将研究氧化应激在诱导从caspase-2敲除和野生型小鼠中分离出的破骨细胞的自发凋亡中的作用。我们的第二个目的涉及确定caspase-2和衰老在成骨细胞 - 骨细胞相互作用中的作用。这将通过测量已显示出影响成骨细胞生成的不同因素的表达水平来实现。这些因素将由骨髓培养物（包含成骨细胞和破骨细胞）中的骨髓培养物测量，这些因素是由年轻和老式caspase-2敲除和野生型小鼠产生的。此外，来自共培养的富含因子的培养基将用作条件培养基，以研究前体细胞中的成骨细胞生成和破骨细胞发生。一方面了解caspase-2在年龄依赖性骨质疏松症中的功能，并显示成骨细胞 - 骨细胞相互作用的变化如何导致严重的骨吸收，另一方面，将导致推定的分子靶标，这些分子靶标可能会发展为新的和有价值的抗肌病治疗。公共卫生相关性：骨质疏松症是一种使人衰弱的疾病，会导致老年人严重骨质流失。这项研究将有助于阐明与骨吸收相关的破骨细胞的细胞死亡的分子机制。鉴定调节破骨细胞细胞死亡的分子靶标将有助于促进创建新策略以治疗骨质疏松症。