人脐带间充质干细胞对放射线照射后人肺成纤维细胞中经典WNT/β-catenin通路的影响

目的探讨人脐带间充质干细胞(HUMSCs)对放射线照射后的人肺成纤维细胞(HLFs)影响的机制。方法 HLFs分为照射组(A)、照射+共培养组(B)和正常对照组(C),A组和B组在5Gy X射线照射后,B组与HUMSCs通过Transwell系统共培养。照射12、24、36h后western blot检测HLFs中α-SMA、GSK-3β、p-GSK-3β和胞核内β-catenin蛋白表达,ELISA法检测细胞培养液中WISP-1、SFRP-1蛋白表达。Real time PCR检测正常和B组第36h HUMSCs中SFRP-1 mRNA表达。结果放射线照射后第24h、36h,HLFs中α-SMA、p-GSK-3β、p-GSK-3β/GSK-3β、胞核内β-catenin,以及培养液中WISP-1蛋白表达水平,A组较C组明显升高,而B组较A组明显下降,差异有统计学意义(P0.01);B组培养液中SFRP-1蛋白水平较A组、C组各时间点均显著升高,差异有统计学意义(P0.05);B组第36h的HUMSCs中SFRP-1 mRNA表达明显高于正常HUMSCs,差异有统计学意义(P0.01)。结论 HUMSCs可抑制放射线导致的HLFs中经典WNT/β-catenin通路的活化,并有可能通过该途径影响肺成纤维细胞的分化。

Effect of human umbilical cord mesenchymal stem cells on lung fibroblasts exposed to radiation through the canonical WNT/β-catenin signaling pathway

Objective To investigate the mechanism of human umbilical cord mesenchymal stem cells ( HUMSCs) on irradiated human lung fibroblasts ( HLFs) exposed to radiation through the canonical WNT/β-catenin signaling pathway. Methods HLFs were divided into the irradiated group ( A) , the irradiated+cocultured group (B) and the control group (C). The groups A and B were irradiated by 5Gy X-rays, and then the group B was co-cultured with HUMSCs by Transwell system. 12, 24 and 36 hours after irradiation, the expression ofα-SMA, GSK-3β, p-GSK-3β and β-catenin in nucleus protein were examined by Western blot respectively. The levels of SFRP-1 and WISP-1 protein in conditioned medium ( CM) were examined by ELISA. The mRNA level of co-cultured HUM-SCs 36 hours after irradiation was examined by real time PCR. Results The protein levels ofα-SMA and some com-ponents of the canonical Wnt/-catenin signaling pathway, p-GSK3β/GSK3β,β-catenin, and WISP-1 increased more significantly in the group A than in the group C, and they decreased more obviously in the group B than in the group C (P<0. 01). ELISA showed an increase of SFRP-1 in CM of the group B in contrast with CM of the groups A and C (P<0. 05). The mRNA level of SFRP-1 increased in co-cultured HUMSCs 36 hours after irradiation while compared with normal HUMSCs (P<0. 01). Conclusion HUMSCs can prevent fibroblasts of postradiation from differentiating into myofibroblast, which may be through reversing the activation of canonical Wnt/-catenin signaling pathway.