Epigallocatechin-3-O-gallate up-regulates microRNA-199a-3p expression by down-regulating the expression of cyclooxygenase-2 in stimulated human osteoarthritis chondrocytes.

Osteoarthritis (OA) is a most common form of arthritis worldwide leading to significant disability. MicroRNAs (miRNAs) are non-coding RNAs involved in various aspects of cartilage development, homoeostasis and pathology. Several miRNAs have been identified which have shown to regulate expression of target genes relevant to OA pathogenesis such as matrix metalloproteinase (MMP)-13, cyclooxygenase (COX)-2, etc. Epigallocatechin-3-O-gallate (EGCG), the most abundant and active polyphenol in green tea, has been reported to have anti-arthritic effects, however, the role of EGCG in the regulation of miRNAs has not been investigated in OA. Here, we showed that EGCG inhibits COX-2 mRNA/protein expression or prostaglandin E2 (PGE2 ) production via up-regulating microRNA hsa-miR-199a-3p expression in interleukin (IL)-1β-stimulated human OA chondrocytes. This negative co-regulation of hsa-miR-199a-3p and COX-2 by EGCG was confirmed by transfection of OA chondrocytes with anti-miR-199a-3p. Transfection of OA chondrocytes with anti-miR-199a-3p significantly enhanced COX-2 expression and PGE2 production (P < 0.001), while EGCG treatment significantly inhibited anti-miR-199a-3p transfection-induced COX-2 expression or PGE2 production in a dose-dependent manner. These results were further re-validated by co-treatment of these transfection OA chondrocytes with IL-1β and EGCG. EGCG treatment consistently up-regulated the IL-1β-decreased hsa-miR-199a-3p expression (P < 0.05) and significantly inhibited the IL-1β-induced COX-2 expression/PGE2 production (P < 0.05) in OA chondrocytes transfected with anti-hsa-miR-199a-3p. Taken together, these results clearly indicate that EGCG inhibits COX-2 expression/PGE2 production via up-regulation of hsa-miR-199a-3p expression. These novel pharmacological actions of EGCG on IL-1β-stimulated human OA chondrocytes provide new suggestions that EGCG or EGCG-derived compounds inhibit cartilage breakdown or pain by up-regulating the expression of microRNAs in human chondrocytes.

Rasheed Z ，Rasheed N ，Al-Shobaili HA 《-》

Epigallocatechin-3-O-gallate modulates global microRNA expression in interleukin-1β-stimulated human osteoarthritis chondrocytes: potential role of EGCG on negative co-regulation of microRNA-140-3p and ADAMTS5.

Rasheed Z ，Rasheed N ，Al-Shaya O 《-》

Epigallocatechin-3-O-gallate promotes extracellular matrix and inhibits inflammation in IL-1β stimulated chondrocytes by the PTEN/miRNA-29b pathway.

Yang D ，Cao G ，Ba X ，Jiang H ... -  《-》

MicroRNA-558 regulates the expression of cyclooxygenase-2 and IL-1β-induced catabolic effects in human articular chondrocytes.

Cyclooxygenase-2 (COX-2) is a major prostaglandin E2 (PGE2) synthetic enzyme and is involved in the pathogenesis of chronic inflammation and pain in osteoarthritis (OA). The objective of this study was to directly address whether microRNA (miR)-558 can control the interleukin (IL)-1β-mediated induction of COX-2 and catabolic effects in human articular chondrocytes. Total RNA was extracted from the cartilage tissues of normal and OA donors or cultured human articular chondrocytes. The expression of miR-558 was quantified by TaqMan assay. To investigate the repressive effect of miR-558 on COX-2 expression, human chondrocytes and chondrogenic SW1353 cells were transfected with mature miR-558 or an antisense inhibitor (anti-miR-558). The expression of COX-2 protein was determined by Western blot analysis and the involvement of miR-558 in IL-1β-induced catabolic effects was examined by Western blot analysis and enzyme-linked immunosorbent assay (ELISA). Direct interaction between miR-558 and the putative site in the 3'-untranslated region (UTR) of COX-2 messenger RNA (mRNA) was validated by luciferase reporter assay. Normal human articular cartilage expressed miR-558, and its expression was significantly lower in OA cartilage. Stimulation with IL-1β led to a significant reduction in miR-558 expression in normal and OA chondrocytes. IL-1β-induced activation of MAP kinase (MAPK) and nuclear factor-κB (NF-κB) decreased miR-558 expression and induced COX-2 expression in chondrocytes. The overexpression of miR-558 directly suppressed the luciferase activity of a reporter construct containing the 3'-UTR of human COX-2 mRNA and significantly inhibited IL-1β-induced upregulation of COX-2, while treatment with anti-miR-558 enhanced IL-1β-induced COX-2 expression and reporter activity in chondrocytes. Interestingly, IL-1β-induced activation of NF-κB and expression of matrix metalloproteinase (MMP)-1 and MMP-13 was significantly inhibited by miR-558 overexpression. These findings demonstrated that cartilage homeostasis is influenced by miR-558, which directly targets COX-2 and regulates IL-1β-stimulated catabolic effects in human chondrocytes.

Park SJ ，Cheon EJ ，Kim HA 《-》

MicroRNA-199a* regulates the expression of cyclooxygenase-2 in human chondrocytes.

Akhtar N ，Haqqi TM 《-》