背景:本研究旨在研究利拉鲁肽(LIRA)对GLP-1R激动剂的作用,并揭示与软骨细胞中AGEs/RAGE相关的机制。
方法:为了说明GLP-1R激动剂对AGEs诱导的软骨细胞的潜在影响,通过AGEs与LIRA和GLP-1R抑制剂exendin一起施用软骨细胞。使用ELISA评估炎症因子。实时PCR用于评估MMPs和ADAMTSmRNA水平的分解代谢活性,以及合成代谢活性(聚集蛋白聚糖和胶原蛋白II)。通过Western印迹研究RAGE表达。TUNEL,caspase3活性和免疫荧光检测细胞凋亡活性。
结果:我们的结果显示用>100nM的LIRA处理减弱了AGE诱导的软骨细胞活力。Westernbolt表明,与AGEs组相比,通过LIRA治疗激活的GLP-1R降低了RAGE蛋白表达。ELISA显示,LIRA阻碍了AGEs诱导的原代软骨细胞中炎性细胞因子(IL-6,IL-12和TNF-α)的产生。AGEs诱导的分解代谢水平(MMP-1,-3,-13和ADAMTS-4,5)也被LIRA减弱,导致保留更多的细胞外基质(Aggrecan和胶原蛋白II)。TUNEL,caspase3活性和免疫荧光结果表明,LIRA抑制了AGEs诱导的原代软骨细胞炎性细胞因子的产生,并减弱了caspase3的水平,导致凋亡活性降低。所有的保护作用被exendin(GLP-1R阻断剂)逆转。
结论:本研究首次证明LIRA,GLP-1R的激动剂通常用于2型糖尿病,通过抑制RAGE信号传导逆转AGEs诱导的软骨细胞炎症和凋亡,有助于减少分解代谢和保留更多的细胞外基质。上述结果表明GLP-1R激动剂对治疗OA的可能作用。
BACKGROUND: This study aimed to investigate functions of GLP-1R agonist by liraglutide (LIRA) and revealing the mechanism related to AGEs/RAGE in chondrocytes.
METHODS: To illustrate potential effect of GLP-1R agonist on AGEs induced chondrocytes, chondrocytes were administrated by AGEs with LIRA and GLP-1R inhibitor exendin. Inflammatory factors were assessed using ELISA. Real-time PCR was used to evaluate the catabolic activity MMPs and ADAMTS mRNA level, as well as anabolic activity (aggrecan and collagen II). RAGE expression was investigated by Western blotting. TUNEL, caspase3 activity and immunofluorescence were performed to test the apoptotic activity.
RESULTS: Our results showed that treatment with LIRA at > 100 nM attenuated the AGE-induced chondrocyte viability. Western bolt demonstrated that GLP-1R activation by LIRA treatment reduced RAGE protein expression compared with the AGEs groups. ELISA showed that LIRA hindered the AGEs-induced production of inflammatory cytokines (IL-6, IL-12 and TNF-α) in primary chondrocytes. AGEs induced catabolism levels (MMP-1, -3, -13 and ADAMTS-4, 5) are also attenuated by LIRA, causing the retention of more extracellular matrix (Aggrecan and Collagen II). TUNEL, caspase3 activity and immunofluorescence results indicated that LIRA inhibited the AGEs-induced production of inflammatory cytokines in primary chondrocytes and attenuated the caspase 3 level, leading to the reduced apoptotic activity. All the protective effects are reversed by exendin (GLP-1R blockers).
CONCLUSIONS: The present study demonstrates for the first time that LIRA, an agonist for GLP-1R which is commonly used in type 2 diabetes reverses AGEs induced chondrocyte inflammation and apoptosis through suppressing RAGE signaling, contributing to reduced catabolism and retention of more extracellular matrix. The above results indicate the possible effect of GLP-1R agonist on treating OA.