U937细胞向巨噬细胞分化过程中清道夫受体BI(SR-BI)表达的变化

Changes of expression of scavenger receptor class B typeⅠ(SRBI) in phorbol 12-myristate 13-acetate differentiated U937 cells

目的:研究应用佛波酯使U937细胞向巨噬细胞分化过程中清道夫受体B I(SR-B I)蛋白及mRNA表达的变化。方法:用免疫细胞化学法、W estern印迹法及RT-PCR法检测U937细胞诱导分化前和100 nmol/LPMA诱导分化24、48和72 h SR-B I蛋白及mRNA的表达。结果:诱导分化24、48及72 h,免疫细胞化学法检测的U937巨噬细胞SR-B I表达的平均积分吸光度值分别为15.94±3.56、27.86±4.39及9.08±2.37,前两者的平均积分吸光度值明显高于未分化细胞的SR-B I表达(7.76±1.74,P<0.05);W estern印迹法中诱导分化组SR-B I蛋白表达量分别是未分化组的2.08(P<0.05)、3.15(P<0.05)和1.24倍(P>0.05)。RT-PCR结果显示,未分化组与各分化组SR-B I mRNA相对表达量分别是0.112±0.006、0.235±0.014、0.344±0.140和0.138±0.010。结论:U937细胞向巨噬细胞分化过程中SR-B I蛋白及mRNA表达随着时间而先升高后降低,这种变化可能与泡沫细胞形成有关。

AIM： To investigate the changes of expression of SR - BI in phorbol 12 - myristate 13 - acetate （PMA） differentiated U937 cells. METHODS： U937 cells were cultured with 100 nmol/L PMA in order to differentiate the cells to macrophages. Immunocytochemical method, Western blotting analysis and reverse transcription polymerase chain reaction （ RT - PCR） were used to detect SR - BI protein and mRNA during differentiation. RESULTS ： Immunocytochemistry showed that after exposure of U937 cells to PMA for 24, 48, 72 hours, the values of SR - BI protein expression in U937 cells were 15.94 ±3.56, 27. 86 ±4. 39 and 9. 08± 2. 37, with the first two higher than that in undifferentiated cells （7. 76 ± 1.74, P 〈 0.01 ）. Western blotting showed that differentiation resulted in a 2. 08 - fold, 3. 15 - fold （ P 〈 0. 05 ） and 1.24 -fold （P 〉0. 05） increment in the expression of SR -BI protein compared with U937 monocytes. RT- PCR showed that relative SR - BI mRNA expression in different group was 0. 112 ± 0. 006, 0. 235 ± 0. 014, 0. 344 ± 0. 140 and 0. 138 ± 0. 010, respectively. CONCLUSION： SR - BI protein and mRNA were increased after differentiation, reached a peak at 48 hours, and decreased at 72 hours. High expression levels of SR - BI in U937 macrophages following PMA differentiation may be correlated with foam cell formation.