Osteoarthritis (OA) is a degenerative joint disease, and inflammation within an arthritic joint plays a critical role in disease progression. Pro‐inflammatory cytokines, specifically IL‐1 and TNF‐α, induce aberrant expression of catabolic and degradative enzymes and inflammatory cytokines in OA and result in a challenging environment for cartilage repair and regeneration. MicroRNAs (miRNAS) are small noncoding RNAs and are important regulatory molecules that act by binding to target messenger RNAs (mRNAs) to reduce protein synthesis and have been implicated in many diseases, including OA. The goal of this study was to understand the mechanisms of miRNA regulation of the transcriptome of tissue‐engineered cartilage in response to IL‐1β and TNF‐α using an in vitro murine induced pluripotent stem cell (miPSC) model system. We performed miRNA and mRNA sequencing to determine the temporal and dynamic responses of genes to specific inflammatory cytokines as well as miRNAs that are differentially expressed (DE) in response to both cytokines or exclusively to IL‐1β or TNF‐α. Through integration of mRNA and miRNA sequencing data, we created networks of miRNA‐mRNA interactions which may be controlling the response to inflammatory cytokines. Within the networks, hub miRNAs, miR‐29b‐3p, miR‐17‐5p, and miR‐20a‐5p, were identified. As validation of these findings, we found that delivery of miR‐17‐5p and miR‐20a‐5p mimics significantly decreased degradative enzyme activity levels while also decreasing expression of inflammation‐related genes in cytokine‐treated cells. This study utilized an integrative approach to determine the miRNA interactome controlling the response to inflammatory cytokines and novel mediators of inflammation‐driven degradation in tissue‐engineered cartilage.

中文翻译：

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小鼠诱导的多能干细胞衍生软骨细胞对炎症细胞因子的 miRNA-mRNA 相互作用组

骨关节炎 (OA) 是一种退行性关节疾病，关节炎关节内的炎症在疾病进展中起着关键作用。促炎细胞因子，特别是 IL-1 和 TNF-α，在 OA 中诱导分解代谢和降解酶以及炎性细胞因子的异常表达，并导致软骨修复和再生的挑战环境。MicroRNA (miRNA) 是小的非编码 RNA，是重要的调节分子，通过与目标信使 RNA (mRNA) 结合来减少蛋白质合成，并与许多疾病有关，包括 OA。本研究的目的是使用体外鼠诱导多能干细胞 (miPSC) 模型系统了解 miRNA 对 IL-1β 和 TNF-α 响应的组织工程软骨转录组的调控机制。我们进行了 miRNA 和 mRNA 测序，以确定基因对特定炎性细胞因子以及对两种细胞因子或仅对 IL-1β 或 TNF-α 差异表达 (DE) 的 miRNA 的时间和动态反应。通过整合 mRNA 和 miRNA 测序数据，我们创建了 miRNA-mRNA 相互作用网络，这可能控制对炎症细胞因子的反应。在网络中，确定了枢纽 miRNA、miR-29b-3p、miR-17-5p 和 miR-20a-5p。作为对这些发现的验证，我们发现 miR-17-5p 和 miR-20a-5p 模拟物的递送显着降低了降解酶活性水平，同时还降低了细胞因子处理细胞中炎症相关基因的表达。