Kreiner Frederik Flindt, Borup Rehannah, Nielsen Finn Cilius, Schjerling Peter, Galbo Henrik
Institute for Inflammation Research, Department of Rheumatology Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Center for Genomic Medicine Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
BMC Musculoskelet Disord. 2017 Aug 7;18(1):341. doi: 10.1186/s12891-017-1705-z.
The pathophysiology, including the impact of gene expression, of polymyalgia rheumatica (PMR) remains elusive. We profiled the gene expression in muscle tissue in PMR patients before and after glucocorticoid treatment.
Gene expression was measured using Affymetrix Human Genome U133 Plus 2.0 arrays in muscle biopsies from 8 glucocorticoid-naive patients with PMR and 10 controls before and after prednisolone-treatment for 14 days. For 14 genes, quantitative real-time PCR (qRT-PCR, n = 9 in both groups) was used to validate the microarray findings and to further investigate the expression of genes of particular interest.
Prednisolone normalized erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in PMR patients. A total of 165 putatively clinically relevant, differentially expressed genes were identified (cut-off: fold difference > ±1.2, difference of mean > 30, and p < 0.05); of these, 78 genes differed between patients and controls before treatment, 131 genes responded to treatment in a given direction only in patients, and 44 fulfilled both these criteria. In 43 of the 44 genes, treatment counteracted the initial difference. Functional clustering identified themes of biological function, including regulation of protein biosynthesis, and regulation of transcription and of extracellular matrix processes. Overall, qRT-PCR confirmed the microarray findings: Microarray-detected group differences were confirmed for 9 genes in 17 of 18 comparisons (same magnitude and direction of change); lack of group differences in microarray testing was confirmed for 5 genes in 8 of 10 comparisons. Before treatment, using qRT-PCR, expression of interleukin 6 (IL-6) was found to be 4-fold higher in patients (p < 0.05).
This study identifies genes in muscle, the expression of which may impact the pathophysiology of PMR. Moreover, the study adds further evidence of the importance of IL-6 in the disease. Follow-up studies are needed to establish the exact pathophysiological relevance of the identified genes. The study was retrospectively listed on the ISRCTN registry with study ID ISRCTN69503018 and date of registration the 26th of July 2017.
风湿性多肌痛（PMR）的病理生理学，包括基因表达的影响，仍不清楚。我们分析了PMR患者在糖皮质激素治疗前后肌肉组织中的基因表达情况。
使用Affymetrix人类基因组U133 Plus 2.0芯片，对8例初治的PMR患者和10例对照者的肌肉活检样本在泼尼松龙治疗14天前后进行基因表达检测。对于14个基因，采用定量实时PCR（qRT-PCR，两组各n = 9）来验证芯片结果，并进一步研究特定感兴趣基因的表达情况。
泼尼松龙使PMR患者的红细胞沉降率（ESR）和C反应蛋白（CRP）恢复正常。共鉴定出165个可能具有临床相关性的差异表达基因（阈值：倍数差异>±1.2，平均差异>30，p < 0.05）；其中，78个基因在治疗前患者与对照之间存在差异，131个基因仅在患者中对治疗有特定方向的反应，44个基因满足这两个标准。在这44个基因中的43个中，治疗抵消了初始差异。功能聚类确定了生物学功能主题，包括蛋白质生物合成的调节、转录调节和细胞外基质过程调节。总体而言，qRT-PCR证实了芯片结果：在18次比较中的17次中，9个基因的芯片检测到的组间差异得到证实（变化幅度和方向相同）；在10次比较中的8次中，5个基因的芯片检测缺乏组间差异得到证实。治疗前，使用qRT-PCR发现患者白细胞介素6（IL-6）的表达高4倍（p < 0.05）。
本研究鉴定了肌肉中的基因，其表达可能影响PMR的病理生理学。此外，该研究进一步证明了IL-6在该疾病中的重要性。需要进行后续研究以确定所鉴定基因的确切病理生理相关性。该研究已追溯登记在ISRCTN注册中心，研究编号为ISRCTN69503018，注册日期为2017年7月26日。
