Research Centre for Experimental Orthopaedics, Orthopaedic University Hospital Heidelberg, Heidelberg, Germany.
Department of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR, United States.
Osteoarthritis Cartilage. 2019 Aug;27(8):1208-1218. doi: 10.1016/j.joca.2019.04.010. Epub 2019 Apr 19.
Elucidation of whether miRs are involved in mechanotransduction pathways by which cartilage is maintained or disturbed has a particular importance in our understanding of osteoarthritis (OA) pathophysiology. The aim was to investigate whether mechanical loading influences global miR-expression in human chondrocytes and to identify mechanosensitive miRs responding to beneficial and non-beneficial loading regimes as potential to obtain valuable diagnostic or therapeutic targets to advance OA-treatment.
Mature tissue-engineered human cartilage was subjected to two distinct loading regimes either stimulating or suppressing proteoglycan-synthesis, before global miR microarray analysis. Promising candidate miRs were selected, re-evaluated by qRT-PCR and tested for expression in human healthy vs OA cartilage samples.
After anabolic loading, miR microarray profiling revealed minor changes in miR-expression while catabolic stimulation produced a significant regulation of 80 miRs with a clear separation of control and compressed samples by hierarchical clustering. Cross-testing of selected miRs revealed that miR-221, miR-6872-3p, miR-6723-5p were upregulated by both loading conditions while others (miR-199b-5p, miR-1229-5p, miR-1275, miR-4459, miR-6891-5p, miR-7150) responded specifically after catabolic loading. Mechanosensitivity of miR-221 correlated with pERK1/2-activation induced by both loading conditions. The miR-response to loading was transient and a constitutive deregulation of mechano-miRs in OA vs healthy articular cartilage was not observed.
MiRs with broader vs narrower mechanosensitivity were discovered and the first group of mechanosensitive miRs characteristic for non-beneficial loading was defined that may shape the proteome differentially when cartilage tissue is disturbed. The findings prompt future investigations into miR-relevance for mechano-responsive pathways and the corresponding miR-target molecules.
阐明 miR 是否参与软骨维持或破坏的力学转导途径，这对于我们理解骨关节炎（OA）病理生理学具有特殊意义。本研究旨在探讨机械负荷是否影响人软骨细胞的整体 miR 表达，并确定对有益和无益负荷反应的机械敏感 miR，以作为获得有价值的诊断或治疗靶点，推进 OA 治疗的可能性。
成熟的组织工程化人软骨在受到两种不同的负荷刺激，分别刺激或抑制蛋白聚糖合成后，进行整体 miR 微阵列分析。选择有前途的候选 miR，通过 qRT-PCR 重新评估，并在健康对照和 OA 软骨样本中测试其表达。
在合成代谢负荷后，miR 微阵列分析显示 miR 表达的微小变化，而分解代谢刺激则导致 80 个 miR 的显著调节，通过层次聚类清楚地分离了对照和压缩样本。对选定 miR 的交叉测试表明，miR-221、miR-6872-3p、miR-6723-5p 被两种负荷条件上调，而其他 miR（miR-199b-5p、miR-1229-5p、miR-1275、miR-4459、miR-6891-5p、miR-7150）则仅在分解代谢负荷后特异性应答。miR-221 的力学敏感性与两种负荷条件诱导的 pERK1/2 激活相关。miR 对负荷的反应是短暂的，OA 与健康关节软骨之间并未观察到机械 miR 的持续失调。
发现了具有更广泛或更狭窄力学敏感性的 miR，并且定义了第一组对无益负荷有特征性的机械敏感 miR，这些 miR 可能在软骨组织受到干扰时对蛋白质组产生不同的影响。这些发现促使进一步研究 miR 在机械反应途径中的相关性及其相应的 miR 靶分子。
