MicroRNAs (miRNAs) are small non-coding single-stranded RNAs of about 22 nucleotides in length that act as post-transcriptional regulators of gene expression. Depending on the complementarity between miRNA and target mRNA, cleavage, destabilization, or translational suppression of mRNA occurs within the RISC (RNA-induced silencing complex). As gene expression regulators, miRNAs are involved in a variety of biological functions. Dysregulation of miRNAs and their target genes contribute to the pathophysiology of many diseases, including autoimmune and inflammatory disorders. MiRNAs are also present extracellularly in their stable form in body fluids. Their incorporation into membrane vesicles or protein complexes with Ago2, HDL, or nucleophosmin 1 protects them against RNases. Cell-free miRNAs can be delivered to another cell in vitro and maintain their functional potential. Therefore, miRNAs can be considered mediators of intercellular communication. The remarkable stability of cell-free miRNAs and their accessibility in body fluid makes them potential diagnostic or prognostic biomarkers and potential therapeutic targets. Here we provide an overview of the potential role of circulating miRNAs as biomarkers of disease activity, therapeutic response, or diagnosis in rheumatic diseases. Many circulating miRNAs reflect their involvement in the pathogenesis, while for plenty, their pathogenetic mechanisms remain to be explored. Several miRNAs described as biomarkers were also shown to be of therapeutic potential, and some miRNAs are already tested in clinical trials.

MicroRNA (miRNA) 是长度约为 22 个核苷酸的小型非编码单链 RNA，充当基因表达的转录后调节因子。根据 miRNA 和目标 mRNA 之间的互补性，RISC（RNA 诱导沉默复合物）内会发生 mRNA 的切割、不稳定或翻译抑制。作为基因表达调节因子，miRNA 参与多种生物学功能。miRNA 及其靶基因的失调导致许多疾病的病理生理学，包括自身免疫性疾病和炎症性疾病。miRNA 也以稳定的形式存在于细胞外的体液中。它们与 Ago2、HDL 或核磷蛋白 1 结合到膜囊泡或蛋白质复合物中，可保护它们免受 RNase 的侵害。游离 miRNA 可以被传递到另一个细胞体外并保持其功能潜力。因此，miRNA可以被认为是细胞间通讯的介质。无细胞 miRNA 的卓越稳定性及其在体液中的可接近性使它们成为潜在的诊断或预后生物标志物和潜在的治疗靶点。在这里，我们概述了循环 miRNA 作为风湿病疾病活动、治疗反应或诊断的生物标志物的潜在作用。许多循环的 miRNA 反映了它们参与发病机制，而对于很多，它们的发病机制仍有待探索。一些被描述为生物标志物的 miRNA 也被证明具有治疗潜力，并且一些 miRNA 已经在临床试验中进行了测试。