Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai, China (mainland).
Department of Histology and Embryology, Medical College, Nantong University, Nantong, Jiangsu, China (mainland).
Med Sci Monit. 2018 Dec 12;24:9007-9018. doi: 10.12659/MSM.912862.
BACKGROUND Acyl-coenzymeA: cholesterol acyltransferase (ACAT) 1, a key enzyme converting excess free cholesterol to cholesterol esters, has been demonstrated to be associated with the pathogenesis of Alzheimer disease (AD). However, the mechanism underlying the protective role of ACAT1 blockage in AD progression remains elusive. MATERIAL AND METHODS Human neuroblastoma SH-SY5Y cells were treated for 24 h with increasing concentrations of aggregated Aβ₂₅₋₃₅ (5, 15, 25, and 45 μmol) with or without the ACAT1 siRNA pretreatment. Cell viability analysis was measured by CCK-8 assay. The genome-wide correlation between ACAT1 and all other probe sets was measured by the Pearson correlation coefficient (r). Western blotting was used to detect the ACAT1 protein expression in the hippocampus of APP/PSN transgenic AD mice. The mRNA level for each target was analyzed by qPCR. Western blotting was used to detect the ACAT1, cyclo-oxygenase-2 (Cox2), Calcium voltage-gated channel subunits (CACNAs), and ERK/PKC proteins in SH-SY5Y cells with or without the ACAT1 siRNA pretreatment in the presence of Aβ₂₅₋₃₅. RESULTS The expression of ACAT1 was significantly increased in the hippocampus of APP/PSN mice, and also showed an increasing trend when SH-SY5Y cells were exposed to Aβ₂₅₋₃₅. Silencing ACAT1 significantly attenuated Aβ-induced cytotoxicity and cell apoptosis in SH-SY5Y cells. The genome-wide correlation analysis showed that Ptgs2 had the most significant correlation with Acat1 in the hippocampus of BXD RI mice. We further determined the regulatory effect of ACAT1 on COX2 expression by silencing or over-expressing ACAT1 in SH-SY5Y cells and found that silencing ACAT1 played a protective role in AD progression by regulating CACNAs and PKC/ERK signaling cascades. CONCLUSIONS Silencing ACAT1 attenuates Aβ₂₅₋₃₅-induced cytotoxicity and cell apoptosis in SH-SY5Y cells, which may due to the synergistic effect of ACAT1 and COX2 through PKC/ERK pathways.
酰基辅酶 A：胆固醇酰基转移酶（ACAT）1 是将过量游离胆固醇转化为胆固醇酯的关键酶，已被证明与阿尔茨海默病（AD）的发病机制有关。然而，ACAT1 阻断在 AD 进展中的保护作用的机制仍不清楚。
用浓度逐渐增加的聚集态 Aβ₂₅₋₃₅（5、15、25 和 45 μmol）处理人神经母细胞瘤 SH-SY5Y 细胞 24 小时，并用或不用 ACAT1 siRNA 预处理。通过 CCK-8 测定法测量细胞活力分析。通过 Pearson 相关系数（r）测量 ACAT1 与所有其他探针组之间的全基因组相关性。用 Western blot 法检测 APP/PSN 转基因 AD 小鼠海马中的 ACAT1 蛋白表达。通过 qPCR 分析每个靶标的 mRNA 水平。用 Western blot 法检测 SH-SY5Y 细胞中 ACAT1、环氧化酶-2（Cox2）、钙电压门控通道亚基（CACNAs）和 ERK/PKC 蛋白的表达，并用或不用 ACAT1 siRNA 预处理，同时存在 Aβ₂₅₋₃₅。
ACAT1 的表达在 APP/PSN 小鼠的海马中显著增加，当 SH-SY5Y 细胞暴露于 Aβ₂₅₋₃₅时也表现出增加的趋势。沉默 ACAT1 可显著减轻 SH-SY5Y 细胞中 Aβ 诱导的细胞毒性和细胞凋亡。全基因组相关性分析显示，BXD RI 小鼠海马中 Ptgs2 与 Acat1 相关性最强。我们进一步通过在 SH-SY5Y 细胞中沉默或过表达 ACAT1 来确定 ACAT1 对 COX2 表达的调节作用，发现沉默 ACAT1 通过调节 CACNAs 和 PKC/ERK 信号级联发挥 AD 进展的保护作用。
沉默 ACAT1 可减轻 SH-SY5Y 细胞中 Aβ₂₅₋₃₅诱导的细胞毒性和细胞凋亡，这可能是由于 ACAT1 和 COX2 通过 PKC/ERK 途径的协同作用。
