Gastrodin Ameliorates the Inflammation, Oxidative Stress, and Extracellular Matrix Degradation of IL-1ß-Mediated Fibroblast-Like Synoviocytes via Suppressing the Gremlin-1/NF-κB Pathway.

BACKGROUND: Synovial inflammation plays a crucial role in osteoarthritis (OA). Gastrodin (GAS), an active ingredient derived from the Gastrodia elata Blume rhizome, possesses antioxidant and anti-inflammatory pharmacological effects. This research aimed to evaluate the function and molecular mechanism of GAS on human fibroblast-like synoviocytes of osteoarthritis (HFLS-OA) induced by interleukin (IL)-1ß. METHODS: The impact of GAS on the viability of IL-1ß-treated HFLS-OA cells was assessed using the cell counting kit-8 (CCK-8). Quantitative real-time reverse transcription PCR (qRT-PCR) was employed to detect changes in IL-8, IL-6, monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor (TNF)-α, and Gremlin-1 mRNA expression in each group. Corresponding kits were utilized to measure the catalase (CAT) and superoxide dismutase (SOD) activities, as well as the nitric oxide (NO) level. Western blot analysis was conducted to examine the expression of extracellular matrix degradation-associated proteins and nuclear factor kappa-B (NF-κB) pathway-correlated proteins in each group. RESULTS: GAS significantly promoted the proliferation of IL-1ß-induced HFLS-OA cells and concurrently down-regulated Gremlin-1 mRNA expression (p < 0.05). Through the down-regulation of Gremlin-1 expression, GAS exhibited the following effects: decreased IL-8, IL-6, and TNF-α mRNA expression, as well as NO levels (p < 0.05); increased SOD and CAT activities (p < 0.05); down-regulated matrix metallopeptidase 13 (MMP-13) and MMP-1 protein expression levels (p < 0.01); and up-regulated collagen II protein expression level (p < 0.01) in IL-1ß-treated HFLS-OA cells. Additionally, GAS decreased phospho-inhibitory kappa B (p-IκB)/IκB, phospho-inhibitory kappa B kinase (p-IKK)/IKK, and p-p65/p65 ratios in IL-1ß-induced HFLS-OA cells by inhibiting Gremlin-1 expression (p < 0.01). CONCLUSION: GAS demonstrates a positive impact on inflammation, oxidative stress, and extracellular matrix degradation in IL-1ß-mediated HFLS-OA cells. This effect is achieved by suppressing Gremlin-1 expression and reducing NF-κB pathway activity.

Gremlin-1 promotes IL-1ß-stimulated chondrocyte inflammation and extracellular matrix degradation via activation of the MAPK signaling pathway.

The role and mechanism of Gremlin-1 in osteoarthritis (OA) were expected to be probed in this study. Firstly, an in vitro OA model was constructed by stimulating human chondrocyte cell line CHON-001 with IL-1ß. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were utilized for assessing the effect of IL-1ß with different concentrations (5, 10, and 20 ng/mL) on the activity and Gremlin-1 messenger RNA of CHON-001 cells, respectively. Besides, the influence of knocking down/over-expressing Gremlin-1 on the inflammatory factors (IL-6, TNF-α, IL-18 and PGE2), oxidative stress-related substances (malondialdehyde [MDA]; superoxide dismutase [SOD]; lactate dehydrogenase [LDH]), extracellular matrix (ECM) degradation-related proteins, and mitogen-activated protein kinase (MAPK) pathway proteins in IL-1ß-stimulated CHON-001 cells were tested by enzyme-linked immunosorbent assay, related kits, qRT-PCR, and western blot, respectively. IL-1ß inhibited CHON-001 cell proliferation and upregulated Gremlin-1 expression in a concentration-dependent manner. Overexpression of Gremlin-1 increased the IL-6, TNF-α, IL-18, PGE2, and MDA levels, enhanced the LDH activity, and decreased the SOD activity in IL-1ß-induced CHON-001 cells; while the effect of Gremlin-1 knockdown on the above factors was in contrast with that of the overexpression. Furthermore, overexpression of Gremlin-1 upregulated protein expression of matrix metalloproteinase (MMP)-3, MMP-13, and ADAMTS4 while downregulated protein expression of collagen III, aggrecan, and SOX-9 in IL-1ß-stimulated CHON-001 cells. Besides, overexpression of Gremlin-1 increased the p-p38/p38 value while decreased the p-JNK/JNK value in L-1ß-stimulated CHON-001 cells; however, knockdown of Gremlin-1 reversed the above results. Gremlin-1 may promote IL-1ß-stimulated CHON-001 cell inflammation and ECM degradation by activating the MAPK signaling pathway.