[Regulation of colony-stimulating factor 1 receptor inhibitor pexidartinib on the senescence of mouse bone marrow-derived macrophages stimulated by lipopolysaccharide].

Objective: To investigate the effects of colony-stimulating factor 1 receptor (CSF-1R) inhibitor pexidartinib (PLX3397) on the senescence of bone marrow-derived macrophages (BMDM) stimulated by lipopolysaccharide (LPS). Methods: BMDM were isolated and cultured from femurs and tibiae of 10 male C57BL/6 mice aged 6-8 weeks (obtained from Laboratory Animal Center of Guizhou Medical University). They were divided into blank control group, LPS group (treated with 1 μg/ml LPS for 24 h) as well as low, medium and high concentration PLX3397 pretreatment groups (treated with 100, 500 and 1 000 nmol/L PLX3397 for 4 h respectively followed by 1 μg/ml LPS for 24 h). The corresponding markers of macrophages were detected by flow cytometry. Cell viability was detected by cell counting kit-8 and cellular senescence was detected by senescence-associated-β-galactosidase (SA-β-gal) staining. Meanwhile, protein expressions of cycle-dependent kinase inhibitor p16, p21 and CSF-1R were detected by Western blotting, and the expressions of p16 and p21 were detected by intracellular immunofluorescence. Real-time fluorescence quantitative PCR (RT-qPCR) was used to investigate the mRNA levels of senescence-associated secretory phenotype (SASP) genes including interleukin (IL), IL-1β, chemokine-1/10 (CXCL-1/10), matrix metalloproteinase-8 (MMP-8), and transforming growth factor-β (TGF-β). Results: The rate of SA-β-gal positive staining in medium and high concentration PLX3397 pretreatment groups [(39.33±4.93)% and (36.33±3.06)% respectively] were significantly downregulated compared with LPS group [(52.00±3.00)%] (P=0.020, P=0.005). The expression of CSF-1R protein in low, medium and high concentration PLX3397 pretreatment groups were (0.74±0.18, 0.61±0.07, 0.54±0.06), all of which were significantly lower than that in LPS group (1.16±0.08) (P=0.013, P=0.002, P<0.001). The expression levels of CSF-1R mRNA in low, medium and high concentration PLX3397 pretreatment groups (1.04±0.06, 0.90±0.05, 1.18±0.08) showed similar trend (2.90±0.25) (P<0.001). The average fluorescence intensity of p16 in all PLX3397 pretreatment groups were 49.76±3.65, 48.21±1.72, 47.99±1.26 respectively, which were significantly lower than that in LPS group (66.88±5.85) (P=0.001, P<0.001, P<0.001). The average fluorescence intensity of p21 in medium and high concentration PLX3397 pretreatment groups were (34.43±3.62, 30.13±0.86), significantly lower than that in LPS group (46.82±5.33) (P=0.043, P=0.007). The expression of p16 protein in low, medium and high concentration PLX3397 pretreatment groups (0.56±0.04, 0.55±0.04, 0.35±0.19) were significantly lower than that in LPS group (0.98±0.10) (P=0.003, P=0.002, P<0.001), as well the expression of p21 protein (0.69±0.20, 0.42±0.08, 0.26±0.14) (P=0.032, P=0.002, P<0.001). According to the results of RT-qPCR, the expressions of IL-6, IL-1β, CXCL-1, CXCL-10 and MMP-8 in PLX3397 pretreatment groups were significantly lower than those in LPS group (P<0.001), while the expression of TGF-β increased (P<0.001). Conclusions: LPS could induce the cell senescence, increase the secretion of SASP and aggravate local inflammation by activating the CSF-1R on the cell surface of bone marrow-derived macrophages. CSF-1R inhibitor PLX3397 might attenuate CSF-1R activation associated with LPS and inhibit the senescence of bone marrow-derived macrophages induced by LPS.目的： 探讨集落刺激因子1受体（colony-stimulating factor 1 receptor，CSF-1R）抑制剂培西达替尼（pexidartinib，PLX3397）对脂多糖（lipopolysaccharide，LPS）刺激下的骨髓来源巨噬细胞（bone marrow-derived macrophages，BMDM）衰老的调节作用。 方法： 从10只6~8周龄雄性C57BL/6小鼠（贵州医科大学实验动物中心获取）的股骨和胫骨分离、培养BMDM，将BMDM分为空白对照组、LPS组（1 μg/ml LPS处理24 h）和低、中、高浓度PLX3397预处理组（分别给予100、500和1 000 nmol/L PLX3397处理4 h后，再以1 μg/ml LPS处理24 h），采用细胞计数（cell counting kit-8，CCK-8）试剂盒检测细胞活力；通过衰老相关β-半乳糖苷酶（senescence-associated-β-galactosidase，SA-β-gal）染色检测细胞衰老；蛋白质印迹法检测细胞周期依赖性激酶抑制因子p16、p21和CSF-1R的蛋白表达；细胞免疫荧光法检测p16、p21在细胞内的表达；实时定量PCR（real-time fluorescence quantitative PCR，RT-qPCR）检测衰老相关分泌表型（senescence-associated secretory phenotype，SASP）因子包括白细胞介素（interleukin，IL）、趋化因子1/10（chemokine-1/10，CXCL-1/10）、基质金属蛋白酶8（matrix metalloproteinase-8，MMP-8）、转化生长因子-β（transforming growth factor-β，TGF-β）的mRNA表达。 结果： 中、高浓度PLX3397预处理组SA-β-gal染色阳性细胞率［分别为（39.33±4.93）%、（36.33±3.06）%］均较LPS组［（52.00±3.00）%］显著下调（P=0.020，P=0.005）；低、中、高浓度PLX3397预处理组CSF-1R的蛋白表达（分别为0.74±0.18、0.61±0.07、0.54±0.06）均较LPS组（1.16±0.08）显著下调（P=0.013，P=0.002，P<0.001）；低、中、高浓度PLX3397预处理组CSF-1R的mRNA表达（分别为1.04±0.06、0.90±0.05、1.18±0.08）均较LPS组（2.90±0.25）显著下调（P<0.001）；低、中、高浓度PLX3397预处理组p16平均荧光强度（分别为49.76±3.65、48.21±1.72、47.99±1.26）均显著低于LPS组（66.88±5.85）（P=0.001，P<0.001，P<0.001）；中、高浓度PLX3397预处理组p21平均荧光强度（分别为34.43±3.62、30.13±0.86）均较LPS组（46.82±5.33）显著下调（P=0.043，P=0.007）；低、中、高浓度PLX3397预处理组p16蛋白表达（分别为0.56±0.04、0.55±0.04、0.35±0.19）均较LPS组（0.98±0.10）显著下调（P=0.003，P=0.002，P<0.001）。低、中、高浓度PLX3397预处理组p21蛋白表达（分别为0.69±0.20、0.42±0.08、0.26±0.14）均较于LPS组（1.16±0.24）显著降低（P=0.032，P=0.002，P<0.001）。RT-qPCR结果显示，与LPS组相比，PLX3397预处理组IL-6、IL-1β、CXCL-1、CXCL-10、MMP-8的表达均显著降低（P<0.001），TGF-β mRNA表达水平显著升高（P<0.001）。 结论： LPS可通过激活BMDM表面CSF-1R诱发细胞衰老，分泌SASP因子，加重局部炎症反应；CSF-1R抑制剂PLX3397可减弱LPS关联的CSF-1R激活，抑制LPS诱导的BMDM衰老。.