单核细胞向巨噬细胞分化过程中CD44mRNA表达和黏附功能的变化

Changes of CD44 mRNA expression and adhesion function during differentiation from monocytes to macrophages

目的探讨单核细胞向巨噬细胞分化过程中CD44 mRNA表达和黏附功能的变化。方法应用豆蔻佛波醇乙酯(PMA)诱导单核细胞系U937向巨噬细胞分化;应用RT-PCR分析U937细胞CD44 mRNA表达变化,并以β-actin作为内参进行半定量评价,并对主要条带进行测序;应用荧光染料BCECF/AM作为探针,测定黏附于激活的内皮细胞上的U937细胞数目。结果与对照组比较,PMA诱导的U937细胞CD44 mRNA总体表达显著增加(P=0.01037),异构体/标准CD44比例显著上升(P=0.0005551),测序结果显示PMA刺激后显著增加的是947 bp(V8+V9+V10)和1208 bp(V7+V8+V9+V10)CD44异构体。同时,PMA刺激后U937细胞黏附功能显著增加(P=0.0029)。结论单核细胞向巨噬细胞分化过程中CD44 mRNA,特别是947bp(V8+V9+V10)和1208 bp(V7+V8+V9+V10)CD44异构体的表达显著增加,可能与细胞黏附功能的增强相关。

Objective To explore the changes of CD44 mRNA expression and adhesion function of U937 cells during differentiation from monocytes to macrophages. Methods U937 cells were induced by phorbol myristate acetate （PMA） to differentiate from monocytes to macrophages. CD44 mRNA expression of U937 cells was analysed with RT-PCR and semiquantitied by J3-actin as internal standard, and major CD44 bands were sequenced. BCECF/AM as indicator, the number of U937 cells attached to activated endothelial cells was counted. Results Compared with control, total CD44 mRNA expression of PMA-induced U937 cells was significantly increased （ P = 0. 01037） , and the ratio of isoforms to standard CD44 was significantly increased （P = 0. 0005551 ）. The isoforms with signicant changes after PMA stimulation were 947 bp （ V8 ＋ V9 ＋ VIO） and 1208 bp（ V7 ＋ V8 ＋ V9 ＋ V10） CD44 isoform. Adhesion function of U937 cells was also significantly increased （P = 0. 0029）. Conclusion During differentiation from monocytes to macrophages, increased CD44 mRNA expression of U937 cells, especially 947bp （ V8 ＋ V9 ＋ V10） and 1208bp （ V7 ＋ V8 ＋ V9 ＋ V10） isoforms, may be associated with enhanced adhesion function.