Tang Guo, Asou Yoshinori, Matsumura Etsuko, Nakagawa Yusuke, Miyatake Kazumasa, Katagiri Hiroki, Nakamura Tomomasa, Koga Hideyuki, Komori Keiichiro, Sekiya Ichiro, Ezura Yoich, Tsuji Kunikazu
Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Department of Nano-Bioscience, Tokyo Medical and Dental University, Tokyo, Japan.
Heliyon. 2022 May 18;8(5):e09476. doi: 10.1016/j.heliyon.2022.e09476. eCollection 2022 May.
IL1β enhances proliferation of synovial mesenchymal stem/stromal cells (synMSCs) although they don't express its receptor, IL1R1/CD121a, on the cell surface. This study was aimed to elucidate the underlying mechanisms of IL1β-mediated growth promotion.
Human synMSCs were isolated from the suprapatellar synovial membrane. Cell proliferation was measured by MTT. Flowcytometric analyses were performed for surface antigen expression. Intracellular signaling pathway was analyzed by western blotting, immunocytochemistry and Q-PCR.
IL1β enhanced proliferation through IL1R1/CD121a because IL1 receptor antagonist (IL1Ra) completely inhibited it. Expression analyses indicated that a short isoform of IL1R1/CD121a is expressed in synMSCs. Immunocytochemistry indicated that IL1R1/CD121a was majorly localized to the cytoplasm. Western blotting indicated that IL1β induced delayed timing of the ERK1/2 phosphorylation and IκBα degradation in synMSCs. Q-PCR analyses for IL1β-target genes indicated that cyclin D was specifically downregulated by a MAPK/ERK inhibitor, U0126, but not by a NFκB inhibitor, TPCA-1. In contrast, the expression of inflammatory cytokines such as IL1α and IL6 are significantly decreased by TPCA-1 but less effectively decreased by U0126.
Our data indicated that the cytoplasmic IL1R1/CD121a transduced IL1β signal in synMSCs. And the growth-promoting effect of IL1β can be separated from its inflammatory cytokine-inducing function in synMSCs.
白细胞介素1β（IL1β）可增强滑膜间充质干/基质细胞（synMSCs）的增殖，尽管这些细胞在细胞表面不表达其受体白细胞介素1受体1（IL1R1）/CD121a。本研究旨在阐明IL1β介导的生长促进的潜在机制。
从髌上滑膜分离出人synMSCs。通过MTT法测定细胞增殖。对表面抗原表达进行流式细胞术分析。通过蛋白质印迹法、免疫细胞化学和定量聚合酶链反应分析细胞内信号通路。
IL1β通过IL1R1/CD121a增强增殖，因为白细胞介素1受体拮抗剂（IL1Ra）可完全抑制该增殖。表达分析表明，synMSCs中表达IL1R1/CD121a的短异构体。免疫细胞化学表明，IL1R1/CD121a主要定位于细胞质。蛋白质印迹法表明，IL1β诱导synMSCs中细胞外信号调节激酶1/2（ERK1/2）磷酸化和IκBα降解的时间延迟。对IL1β靶基因的定量聚合酶链反应分析表明，细胞周期蛋白D被丝裂原活化蛋白激酶/细胞外信号调节激酶（MAPK/ERK）抑制剂U0126特异性下调，但未被核因子κB（NFκB）抑制剂TPCA-1下调。相反，IL1α和IL6等炎性细胞因子的表达被TPCA-1显著降低，但被U0126降低的效果较差。
我们的数据表明，细胞质中的IL1R1/CD121a在synMSCs中传导IL1β信号。并且IL1β的生长促进作用与其在synMSCs中诱导炎性细胞因子的功能可以分离。
