LEUKOCYTE GENE EXPRESSION IN OSTEOARTHRITIS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。骨关节炎是一种以生物力学、遗传易感性和激素影响为特征的疾病。疾病过程影响整个关节结构，包括软骨、滑膜、软骨下骨，这些都是生长因子、细胞因子、蛋白酶和炎症介质产生的活跃部位。在这种疾病中，可靠的生物标志物仍然难以捉摸。我们实验室最近的研究发现，在骨性关节炎患者外周血白细胞(PBMC)被激活，这是意想不到的新奇现象。利用基因表达阵列，发现OA-PBMC差异表达不同于正常对照的转录簇。在上调的转录本中有COX-2；在OA-PBMCs中，细胞因子诱导的PGE2的产生是正常的5倍。在OA-PBMC中也可以鉴定出对药物干预(COX-2特异性抑制剂)敏感的54个转录子簇。与正常软骨和RA软骨不同，人骨关节炎病变软骨表现出不同于正常软骨和RA软骨的(增殖/肿瘤)基因表达特征。本研究的目的是利用基因组技术识别一组由外周血白细胞(PBL)表达的新的生物标记物，这些标记物将在临床上用于识别胫股关节骨关节炎(OA)患者，并识别那些有疾病进展风险的患者。初步数据显示，部分骨性关节炎患者的PBL表现出“细胞因子激活谱”，提示在病变关节组织的灌流过程中，白细胞暴露于刺激物。为了追求这一发现，这项研究将有三个中心目标：特定目标1将确定PBL基因表达模式是否区分早期骨关节炎(OA-E，K-L 2级)、晚期骨关节炎(OA-A，K-L 3级)和健康对照组，如半屈曲、透视定位的膝关节X线片所定义的。对于这三个队列，将分析PBL基因表达谱的总体和配对比较，以确定区分以下特征的独特谱：1)OA与正常，以及2)早期与晚期OA。研究人员将与弗吉尼亚·克劳斯博士合作，在一个独立的人群--杜克膝关节骨性关节炎队列中验证膝骨性关节炎的PBL基因表达谱。特殊目的2将检查PBL基因表达谱与核磁共振和骨显像结果的相关性。研究人员将使用临床3.0T MRI系统对纽约大学HJD医院的180名患者进行MRI研究，这些患者将进入为期两年的纵向队列研究。研究人员将对关节软骨完整性、软骨下狭窄病变、滑膜炎/积液、边缘骨赘进行半定量分析，评估整体和个别骨间隔评分。在与克劳斯博士的合作中，他们还将研究PBL基因表达谱与早期和晚期半定量骨显像分别定义的膝关节信号“滑膜炎”和“全身骨关节炎负担”的相关性。他们将开发一个多变量的OA放射学分期模型，以确定PBL基因表达谱与其他危险因素的独立关联，包括BMI、COMP、骨显像和内翻/外翻畸形。具体目标3将是一项为期两年的纵向研究，以确定特定的PBL基因表达模式是否预测OA疾病的进展。研究人员将通过MRI和半定量膝关节X光检查来评估有进展和无进展的骨性关节炎患者。成像评估将在0个月和24个月进行。除MRI和X光检查外，每个受试者还将接受：1)临床评估，包括BMI测定；2)疼痛和功能评估(完整的WOMAC)；3)血清COMP。此外，还将收集血清、血浆和尿液，用于未来的生物标记物测定。研究人员预计，这些研究将加强我们对OA发病机制的理解，并提供一个组合生物标记物，可以预测OA疾病的进展。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Osteoarthritis (OA) is a disease characterized by altered biomechanics, genetic susceptibility and hormonal influences. The disease process affects the entire joint structure, including cartilage, synovial membrane, subchondral bone, which are active sites of growth factor, cytokine, protease and inflammatory mediator production. Reliable biomarkers remain elusive in this disease. Recent studies in our laboratory revealed the unexpected and novel observation that peripheral blood leukocytes (PBMCs) in OA are activated. Using gene expression array, OA-PBMCs were shown to differentially express clusters of transcripts that were distinct from normal controls. Among the upregulated transcripts was COX-2; cytokine-induced production of PGE2 was 5-fold higher in OA-PBMCs than in normal. A cluster of 54 transcripts sensitive to pharmacological intervention (COX-2 specific inhibitors) could also be identified in OA-PBMCs. Independently, human OA affected cartilage showed a specific (proliferation/neoplastic) gene expression signature in OA, which differed from normal and RA cartilage. The objective of this study is to use genomic technology to identify a novel cluster of biomarkers expressed by peripheral blood leukocytes (PBL) that will be clinically useful in the identification of patients with tibio-femoral knee osteoarthritis (OA), and to identify those patients at risk for disease progression. Preliminary data indicates that PBL derived from a subset of OA patients exhibits a "cytokine activation profile", suggesting leukocyte exposure to stimuli during the course of perfusion of diseased joint tissues. To pursue this finding, this study will have three central aims: Specific aim 1 will determine whether PBL gene expression patterns distinguish early OA (OA-E, K-L grade 2), advanced OA (OA-A, K-L grade 3) and healthy controls as defined by semi-flexed, fluoroscopically-positioned knee radiographs. For these three cohorts, overall and pair-wise comparisons of PBL gene expression profiles will be analyzed in order to identify a distinctive profile which discriminates the following: 1) OA versus normal, and 2) early versus advanced OA. The investigators will validate PBL gene expression profiles of knee OA in an independent population, the Duke Knee OA Cohort, in collaboration with Dr. Virginia Kraus. Specific aim 2 will examine the association of PBL gene expression profiles with findings on MRI and bone scintigraphy. The investigators will perform MRI studies using a clinical 3.0T MRI system on 180 patients at NYU-HJD, who will be entered into a two-year longitudinal cohort study. The investigators will perform semi-quantitative analysis of articular cartilage integrity, subchondral narrow lesions, synovitis/effusion, marginal osteophytes, assessing both global and individual compartment scores. In collaboration with Dr. Kraus they will also examine the association of PBL-gene expression profiles with signal knee "synovitis" and with "total body OA burden," as defined by early and late phase semi-quantitative bone scintigraphy, respectively. They will develop a multivariate model of OA radiographic stage to determine the independent associations of PBL-gene expression profiles with other risk factors including BMI, COMP, bone scintigraphy and varus/valgus deformities. Specific aim 3 will be a two-year longitudinal to determine whether specific PBL gene expression patterns predict OA disease progression. The investigators will assess OA patients with progression and without progression, as determined by both MRI and semi-quantitative knee radiography. Imaging evaluations will occur at 0 and 24 months. In addition to MRI and X-ray, each subject will undergo: 1) clinical evaluation including BMI determination, 2) pain and function assessment (complete WOMAC), 3) serum COMP. In addition, serum, plasma and urine will be collected for future biomarker determinations. The investigators anticipate that these studies will enhance our understanding of the pathogenesis of OA and provide a combinatorial biomarker that may predict OA disease progression.