Beta-Amyloid & Cell Death Mechanisms in Skeletal Muscle

β-淀粉样蛋白

• 批准号: 6711076
• 负责人: HENRY W QUERFURTH
• 金额: $ 27.68万
• 依托单位: STEWARD ST. ELIZABETH'S MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-15 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6711076
• 关键词: Alphaherpesvirinae; amyloid proteins; apoptosis; cell proliferation; cellular pathology; cytotoxicity; electron microscopy; enzyme activity; enzyme linked immunosorbent assay; genetically modified animals; human tissue; immunofluorescence technique; immunoprecipitation; inclusion body; laboratory mouse; mitochondria; myositis; myotubes; polymerase chain reaction; proteasome; protein kinase; striated muscles; terminal nick end labeling; tissue /cell culture; transfection /expression vector; western blottings

DESCRIPTION (Adapted from applicant's abstract): Inclusion Body Myositis (IBM) is the most common muscle disorder in patients over 50 years of age. IBM shares several features with another age-related degenerative disorder, Alzheimer's disease (AD): 1) there are both sporadic and autosomal inherited forms, 2) local inflammatory collections are characteristic but immunosuppressive therapies are only marginally effective, and 3) accumulations of AD-related proteins are a histopathological hallmark. Congo red- reactive deposits consisting of the beta-amyloid peptide (Abeta) are the most notable feature. In contrast with the extra-cellular amyloid plaques of AD, the amyloid deposits of IBM are intracellular. Several other proteins accumulate intracellularly in the vacuolated myofibers of IBM including other epitopes of beta-amyloid precursor protein, hyperphosphorylated filaments comprised of the microtubule-associated protein tau, ubiquitin, the cellular prion protein, and cyclin dependent kinase 5 (cdk5). The mechanism of muscle cell loss in IBM remains a mystery. Abeta is known to induce programmed cell death (apoptosis) of neurons in culture and in some transgenic mouse models for Alzheimer's disease. In Aim 1, the applicants hypothesize that intracellular accumulation of Abeta in cultured skeletal muscle myotubes will induce apoptosis. Abeta deposition is provoked using an inducible promoter, a heterologous viral gene transfer system, or by direct injection. They will examine the role of the proteasome and the parkin gene in the genesis of protein accumulations. In Aim 2, Abeta is established as a myotoxins by a thorough examination of human IBM biopsy specimens, for a correlation between Abeta accumulation and several markers of apoptosis. Mouse muscle is similarly analyzed after direct injection of an Abeta-encoding adenoviral gene construct. Their 2nd hypothesis is that deposition of intracellular Abeta adversely affects Akt kinase-dependent muscle cell survival pathways and in Aim 3 we will determine if Abeta inhibits Akt activity. Furthermore, the applicants will seek evidence that Abeta induces deleterious attempts by cells to re-enter the developmental or even the cell cycle, related to Akt, p21 Cip1/Wafl or cyclin D dysfunction. Evidence for tau hyperphosphorylation from unhindered GSK-3beta activity will be sought. In Aim 4 the functional significance of Akt inhibition by Abeta is examined by asking whether Akt activation will protect muscle cells forced to overexpress Abeta from cell death. While some of the findings may be relevant to neuronal systems, they will provide insight into a novel mechanism of Abeta injury and the complex regulation of cell survival, replication and apoptosis from a key survival signal control point.

描述（改编自申请人的摘要）：包容体肌炎（IBM） 是50岁以上患者中最常见的肌肉障碍。 IBM分享 阿尔茨海默氏症的几个功能患有另一种与年龄相关的退化障碍 疾病（AD）：1）既有零星和常染色体遗传形式，2） 局部炎症收集是特征但免疫抑制的 疗法仅略有效，3）与广告相关的积累 蛋白质是组织病理学的标志。刚果红反应性沉积物 由β-淀粉样蛋白肽（ABETA）组成的是最显着的特征。在 与AD的细胞外淀粉样板块形成鲜明对比， IBM是细胞内的。其他几种蛋白质在细胞内积累 IBM的肌化肌纤维，包括β-淀粉样蛋白前体的其他表位 由微管相关的蛋白质，高磷酸化丝 蛋白质tau，泛素，细胞prion蛋白和细胞周期蛋白依赖性激酶 5（CDK5）。 IBM中肌肉细胞损失的机制仍然是一个谜。 abeta众所周知 诱导培养和某些神经元神经元的程序性细胞死亡（凋亡） 阿尔茨海默氏病的转基因小鼠模型。在AIM 1中，申请人 假设Abeta在培养的骨骼中的细胞内积累 肌肉肌管会诱导凋亡。 Abeta的沉积是使用 诱导启动子，异源病毒基因转移系统或直接 注射。他们将检查蛋白酶体和帕金基因在 蛋白质积累的起源。在AIM 2中，Abeta被确定为 通过对人IBM活检标本进行彻底检查的肌毒素，用于 Abeta积累与凋亡的几个标志物之间的相关性。老鼠 直接注射Abeta编码后，类似地分析了肌肉 腺病毒基因构建体。他们的第二个假设是 细胞内ABETA不利影响Akt激酶依赖性肌肉细胞的存活 途径和目标3中，我们将确定ABETA是否抑制AKT活性。 此外，申请人将寻求证据表明Abeta引起有害的证据 细胞重新进入发育或什至细胞周期的尝试，相关 到AKT，P21 CIP1/WAFL或细胞周期蛋白D功能障碍。 Tau的证据 将寻求未阻碍的GSK-3BETA活性的热磷酸化。目标 4通过询问ABETA抑制AKT的功能意义 AKT激活是否会保护被迫过表达Abeta的肌肉细胞 从细胞死亡。虽然某些发现可能与神经元有关 系统，他们将洞悉Abeta伤害的新机制和 钥匙的细胞存活，复制和凋亡的复杂调节 生存信号控制点。