高磷环境下胆固醇敏感器SCAP功能失调促进巨噬细胞内胆固醇蓄积

发布时间：2018-06-23 08:37

本文选题：巨噬细胞 + 高磷酸盐血症　；参考：《第二军医大学学报》2017年12期

【摘要】：目的观察高磷环境对巨噬细胞内胆固醇蓄积的影响及其分子机制。方法将人单核细胞株(THP-1)源性巨噬细胞分为对照组(磷1.0mmol/L)、高磷处理组(磷3.0mmol/L)、磷甲酸钠(PFA)处理组(磷1.0mmol/L加PFA 1.0mmol/L)以及高磷联合PFA处理组(磷3.0mmol/L加PFA 1.0mmol/L),按不同要求分别处理各组细胞。培养24h后,油红O染色观察细胞内中性脂质的分布,酶催化比色法定量测定细胞内的胆固醇含量,qPCR检测细胞内羟甲基戊二酸单酰辅酶A还原酶(HMGCoAR)、低密度脂蛋白受体(LDLR)、固醇调节元件结合蛋白裂解激活蛋白(SCAP)mRNA的表达,蛋白质印迹法测定细胞内SCAP、LDLR、HMGCoAR及核内固醇调节元件结合蛋白2(N-SREBP2)的蛋白水平,激光共聚焦法检测SCAP从内质网向高尔基体的移位情况。结果与对照组相比,高磷处理组巨噬细胞内中性脂质明显聚集,细胞内总胆固醇与胆固醇酯的含量增加(P0.05),LDLR、HMGCoAR mRNA与蛋白的表达增高(P0.05,P0.01),细胞核内N-SREBP2的蛋白表达水平增加(P0.05),SCAP从内质网向高尔基体的移位增加;PFA处理(高磷联合PFA处理组)可阻断高磷引起的上述作用(P0.05,P0.01)。高磷处理组巨噬细胞内SCAP的蛋白水平相比对照组增高(P0.05),PFA处理能抑制高磷导致的SCAP蛋白水平增高,但SCAP mRNA的表达在各组间差异均无统计学意义(P0.05)。结论高磷环境下,钠磷转运体介导磷离子进入巨噬细胞内,通过基因转录后机制增加SCAP的蛋白水平,诱导其功能失调并促使其异常转运SREBP2至高尔基体裂解释放NSREBP2,后者转位入核促进HMGCoAR和LDLR的表达,促使细胞内源性胆固醇合成和外源性LDL经LDLR摄入的增加,最终导致细胞内胆固醇异常蓄积。
[Abstract]:Objective to observe the effect of high phosphorus on cholesterol accumulation in macrophages and its molecular mechanism. Methods Human monocyte (THP-1) macrophages were divided into control group (P 1.0 mmol / L), high phosphorus treatment group (P 3.0 mmol / L), sodium phosphate formate group (P 1.0 mmol / L + PFA 1.0 mmol / L) and high phosphorus combined PFA group (P 3.0 mmol / L plus PFA 1.0 mmol / L). After 24 hours of culture, the distribution of neutral lipid in cells was observed by oil red O staining. The expression of HMGCoAR, low density lipoprotein receptor (LDLR) and steroid regulatory element binding protein lytic activator (SCAP) mRNA was detected by enzyme catalytic colorimetry and qPCR. The protein levels of SCAP LDLRN HMGCoAR and N-SREBP2 (N-SREBP2) were measured by Western blot. The translocation of SCAP from endoplasmic reticulum to Golgi body was detected by confocal laser. Results compared with the control group, the neutrophil lipid accumulation in the high phosphorus treatment group was significantly higher than that in the control group. The content of total cholesterol and cholesterol ester increased (P0.05) and the expression of HMGCoAR mRNA and protein increased (P0.05 + P0.01), and the protein expression level of N-SREBP2 increased (P0.05). The shift of SCAP from endoplasmic reticulum to Golgi body increased (PFA treatment group). The above effects induced by high phosphorus can be blocked (P0.05, P0.01). The protein level of SCAP in macrophages of high phosphorus treatment group was higher than that of control group (P0.05). PFA treatment could inhibit the increase of SCAP protein level induced by high phosphorus, but the expression of SCAP mRNA had no significant difference among the groups (P0.05). Conclusion in high phosphorous environment, sodium phosphate transporter mediates phosphorous ion into macrophages and increases the protein level of SCAP through gene posttranscriptional mechanism. It induced dysfunction and caused abnormal transport of SREBP2 to Golgi apparatus to release NSREBP2.The latter translocated into nucleus promoted the expression of HMGCoAR and LDLR, promoted intracellular cholesterol synthesis and increased the uptake of exogenous LDL through LDLR. Eventually lead to abnormal accumulation of cholesterol in cells.
【作者单位】：重庆医科大学附属第一医院心血管内科;重庆代谢性疾病转化医学重点实验室;重庆医科大学附属第一医院肾脏内科;
【基金】：国家自然科学基金青年科学基金(81500341)~~
【分类号】：R543.5

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