Aim

Studies have pivoted on the position of microRNAs (miRNAs) in knee osteoarthritis (KOA) but not the more specific function of miR-199-3p. Thus, this study is to uncover the mechanism of miR-199-3p in KOA.

Methods

Rats KOA models were established by modified Hulth method. miR-199-3p expression was observed in cartilage of KOA rats. The binding sites of miR-199-3p were predicted by bioinformatics analysis and the potential interaction between DNA methyltransferase 3A (DNMT3A) and miR-199-3p was verified by dual-luciferase reporter gene assay. Rats were injected with miR-199-3p agomir or antagomir and DNMT3A siRNA into the knee joint. Inflammatory response factors in serum and cartilage tissues, cell apoptosis, and pathological status of cartilage tissues were detected. Chondrocytes were isolated from KOA cartilages and treated with miR-199-3p mimic or inhibitor and DNMT3A siRNA. Chondrocyte proliferation and apoptosis were detected.

Results

miR-199-3p expression was suppressed in cartilage of KOA rats. Dual-luciferase reporter gene assay proved that a miR-199-3p-binding site was located in the 3′UTR of DNMT3A mRNA. Inflammation, chondrocyte apoptosis and cartilage pathological changes were improved by miR-199-3p agomir but aggravated by miR-199-3p antagomir. The effects of miR-199-3p antagomir on KOA rats were partially reversed by DNMT3A siRNA. miR-199-3p mimic or DNMT3A siRNA decreased KOA chondrocytes apoptosis and promoted proliferation. miR-199-3p inhibitor showed the opposite functions to miR-199-3p mimic. The effects of miR-199-3p inhibitor on chondrocytes were reversed by DNMT3A siRNA.

Conclusion

This study highlights that miR-199-3p up-regulation or down-regulation of DNMT3A induces chondrocyte proliferation and inhibits apoptosis in KOA, which may widen our eyes to treat patients with KOA.

中文翻译：

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MicroRNA-199-3p 上调通过 DNMT3A 抑制增强软骨细胞增殖并抑制膝骨关节炎的细胞凋亡

目的

研究的重点是微小 RNA (miRNA) 在膝关节骨关节炎 (KOA) 中的位置，而不是 miR-199-3p 的更具体的功能。因此，本研究旨在揭示 miR-199-3p 在 KOA 中的作用机制。

方法

采用改良Hulth方法建立大鼠KOA模型。在 KOA 大鼠的软骨中观察到 miR-199-3p 表达。通过生物信息学分析预测 miR-199-3p 的结合位点，并通过双荧光素酶报告基因测定验证 DNA 甲基转移酶 3A (DNMT3A) 和 miR-199-3p 之间的潜在相互作用。将 miR-199-3p agomir 或 antagomir 和 DNMT3A siRNA 注射到大鼠膝关节中。检测血清和软骨组织中的炎症反应因子、细胞凋亡和软骨组织的病理状态。从 KOA 软骨中分离出软骨细胞，并用 miR-199-3p 模拟物或抑制剂和 DNMT3A siRNA 处理。检测到软骨细胞增殖和凋亡。

结果

miR-199-3p 表达在 KOA 大鼠的软骨中被抑制。双荧光素酶报告基因检测证明 miR-199-3p 结合位点位于 DNMT3A mRNA 的 3'UTR。炎症、软骨细胞凋亡和软骨病理改变被 miR-199-3p agomir 改善，但被 miR-199-3p antagomir 加重。miR-199-3p antagomir 对 KOA 大鼠的影响被 DNMT3A siRNA 部分逆转。miR-199-3p 模拟物或 DNMT3A siRNA 减少 KOA 软骨细胞凋亡并促进增殖。miR-199-3p 抑制剂显示出与 miR-199-3p 模拟物相反的功能。miR-199-3p抑制剂对软骨细胞的作用被DNMT3A siRNA逆转。

结论

本研究强调 miR-199-3p 上调或下调 DNMT3A 诱导软骨细胞增殖并抑制 KOA 中的细胞凋亡，这可能会拓宽我们治疗 KOA 患者的视野。