Orthopaedic Wear Debris, Vitamin D, and Innate Immunity

骨科磨损碎片、维生素 D 和先天免疫

• 批准号: 7904106
• 负责人: John S Adams
• 金额: $ 17.15万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7904106
• 关键词: Affect; Air; American; Animal Model; Appearance; Arthroplasty; Bone Marrow; Bone Resorption; Cell membrane; Cells; Clinical; Cobalt; Country; Culture Media; Enzyme-Linked Immunosorbent Assay; Evaluation; Event; Exposure to; Failure; Gene Proteins; Hip Prosthesis; Hip region structure; Human; Immune; Immune response; Implant; In Vitro; Individual; Inflammation; Inflammation Mediators; Inflammatory; Interleukin-6; Intervention; Joints; Mediating; Mixed Function Oxygenases; Modeling; Monitor; Monokines; Mus; Natural Immunity; Orthopedics; Osteolysis; Osteolytic; Outcome; Pattern recognition receptor; Physiological; Polyethylenes; Production; Prosthesis; Public Health; RNA Interference; Signal Pathway; Signal Transduction; System; TNFSF11 gene; Testing; Time; Toll-Like Receptor 1; Toll-like receptors; Total Hip Replacement; Transcription factor genes; Vitamin D; Vitamin D3 Receptor; adapter protein; aging population; base; cost; cytokine; design; improved; in vivo; loss of function; macrophage; microbial; particle; protein expression; public health relevance; receptor expression; response; simulation; subcutaneous; therapeutic target; vector

DESCRIPTION (provided by applicant): Clinical failure of total hip replacements involving polyethylene cups and cobalt-chrome femoral components will affect more than a million individuals in the coming 20-year period. Failure in most of these implants will result from the release of polyethylene (PE) wear debris, the appearance of PE particle-dependent inflammation and consequent, aseptic loosening of one or both of the components of the hip prosthesis. The overall aim of this proposal is 1] to ascertain the means by which the exfoliated PE particles engage cells of the host to initiate the innate immune response and 2] to identify opportunities for targeted therapeutic, and perhaps inexpensive, intervention in periprosthetic osteolytic events. As such, it is hypothesized that PE wear particles shed locally by the implant activate Toll-like receptors (TLRs), a subset of pattern recognition receptors embedded in the plasma membrane of macrophages, to direct the elaboration of inflammatory cytokines responsible for osteolysis (e.g. RANKL). This proposal is made possible by the recent discoveries that 1] one can now isolate, purify and characterize in high yield the full spectrum of PE particles generated during physiologic wear simulation and 2] innate immune signaling in primary isolates of human macrophages is mediated by TLRs and impaired by a vitamin D-insufficient status in the host. Two aims are proposed to test the above-stated hypothesis. Specific Aim 1 will seek to determine the TLR response to exposure to authentic, pure wear particles derived from hip simulator studies of conventional polyethylene acetabular cups against cobalt-chrome femoral balls in terms of monokine gene and protein expression. Here TLR-expressing mouse bone marrow-derived macrophages from wild-type and from TLR- and MyD88 (universal adapter protein for TLRs)-deficient mice will be employed to monitor by quantitative PCR and/or ELISA expression of the TLRs and monokines which are known to mediate bone resorption. Initial screens for involved TLRs and TLR-TLR cooperation will utilize TLR-targeted lentiviral shRNAmir expression for loss-of-function RNA interference. Specific Aim 2 will attempt to ascertain in vivo in the mouse subcutaneous air pouch model whether the vitamin D system influences TLR responsivity to wear particles in terms of 1] vitamin D metabolite response modifiers (e.g. the vitamin D-hydroxylases and vitamin D receptor [VDR]), 2] TLR expression and 3] cytokine responses to particle stimulation. These markers of bioresponse will be analyzed quantitatively in vivo under conditions of vitamin D sufficiency, insufficiency, rescue from insufficiency, and TLR and MyD88 deficiency. Considering that the aging population in this country, the majority of which are vitamin D- insufficient, encompasses those who i) already harbor a failing prosthesis or ii) are candidates to receive a hip implant, then reversal of the vitamin D-insufficient state may represent a simple, cost-efficient and effective means of improving outcomes with hip implants in particular and in joint arthroplasties in general. PUBLIC HEALTH RELEVANCE: Clinical failure of existing total hip replacements, estimated to occur in more than a million individuals in the coming 20-year period, results from the release of polyethylene (PE) wear debris from the implant, PE particle- dependent inflammation and consequent periprosthetic osteolysis and loosening of the components of the prosthesis. It is hypothesized that PE wear particles shed locally by the implant will activate the Toll-like receptor (TLR), vitamin D-dependent signaling pathway in macrophages to direct the elaboration of inflammatory cytokines responsible for osteolysis (e.g. RANKL). Considering that the aging population in this country, the majority of which are vitamin D-insufficient, encompasses those who i) already harbor a failing prosthesis or ii) are candidates to receive a hip implant, then reversal of the vitamin D-insufficient state may represent a simple, cost-efficient and effective means of improving outcomes with hip implants in particular and in joint arthroplasties in general.

描述（由申请人提供）：涉及聚乙烯杯和钴铬股骨部件的全髋关节置换术的临床失败将在未来 20 年影响超过一百万人。大多数植入物的失效将由聚乙烯 (PE) 磨损碎片的释放、PE 颗粒依赖性炎症的出现以及随之而来的髋关节假体的一个或两个组件的无菌松动造成。该提案的总体目标是 1] 确定脱落的 PE 颗粒与宿主细胞结合以启动先天免疫反应的方式，以及 2] 确定对假体周围溶骨事件进行靶向治疗且可能廉价干预的机会。因此，假设植入物局部脱落的 PE 磨损颗粒会激活 Toll 样受体 (TLR)（嵌入巨噬细胞质膜中的模式识别受体的一个子集），以指导负责骨溶解的炎症细胞因子的产生（例如 RANKL）。最近的发现使这一提议成为可能：1] 现在可以高产量地分离、纯化和表征在生理磨损模拟过程中产生的全谱 PE 颗粒；2] 人类巨噬细胞初级分离物中的先天免疫信号由 TLR 介导，并受到宿主维生素 D 不足状态的损害。提出了两个目标来检验上述假设。具体目标 1 将寻求确定 TLR 对暴露于真实、纯磨损颗粒的反应，这些颗粒源自传统聚乙烯髋臼杯与钴铬股骨球的髋关节模拟器研究，在单核因子基因和蛋白质表达方面。在这里，来自野生型和 TLR 和 MyD88（TLR 通用接头蛋白）缺陷型小鼠的表达 TLR 的小鼠骨髓来源的巨噬细胞将用于通过定量 PCR 和/或 ELISA 监测已知介导骨吸收的 TLR 和单核因子的表达。对相关 TLR 和 TLR-TLR 合作的初步筛选将利用 TLR 靶向慢病毒 shRNAmir 表达进行功能丧失性 RNA 干扰。具体目标 2 将尝试在小鼠皮下气囊模型中体内确定维生素 D 系统是否影响 TLR 对磨损颗粒的响应，具体体现在 1] 维生素 D 代谢物反应调节剂（例如维生素 D 羟化酶和维生素 D 受体 [VDR]）、2] TLR 表达和 3] 对颗粒刺激的细胞因子反应。这些生物反应标志物将在维生素 D 充足、不足、补救不足以及 TLR 和 MyD88 缺乏的条件下进行体内定量分析。考虑到这个国家的老龄化人口（其中大多数维生素 D 不足）包括 i) 已经出现故障的假体或 ii) 适合接受髋关节植入物的人群，那么逆转维生素 D 不足的状态可能是一种简单、经济高效且有效的方法，可以改善髋关节植入物（尤其是关节置换术）的结果。公共健康相关性：现有全髋关节置换术的临床失败估计在未来 20 年期间将有超过 100 万人发生，其原因是植入物中聚乙烯 (PE) 磨损碎片的释放、PE 颗粒依赖性炎症以及随之而来的假体周围骨溶解和假体部件松动。据推测，植入物局部脱落的 PE 磨损颗粒将激活巨噬细胞中的 Toll 样受体 (TLR)、维生素 D 依赖性信号通路，以指导负责骨溶解的炎症细胞因子的产生（例如 RANKL）。考虑到这个国家的老龄化人口（其中大多数维生素 D 不足）包括 i) 已经出现故障的假体或 ii) 适合接受髋关节植入物的人群，那么逆转维生素 D 不足的状态可能是一种简单、经济高效且有效的方法，可以改善髋关节植入物（尤其是关节置换术）的结果。