Institute of Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom
Institute of Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom.
J Lipid Res. 2019 Jan;60(1):98-110. doi: 10.1194/jlr.M088245. Epub 2018 Nov 5.
We have shown that aggregated LDL is internalized by macrophages and oxidized in lysosomes by redox-active iron. We have now investigated to determine whether the lysosomal oxidation of LDL impairs lysosomal function and whether a lysosomotropic antioxidant can prevent these alterations. LDL aggregated by SMase (SMase-LDL) caused increased lysosomal lipid peroxidation in human monocyte-derived macrophages or THP-1 macrophage-like cells, as shown by a fluorescent probe, Foam-LPO. The pH of the lysosomes was increased considerably by lysosomal LDL oxidation as shown by LysoSensor Yellow/Blue and LysoTracker Red. SMase-LDL induced senescence-like properties in the cells as shown by β-galactosidase staining and levels of p53 and p21. Inflammation plays a key role in atherosclerosis. SMase-LDL treatment increased the lipopolysaccharide-induced secretion of TNF-α, IL-6, and MCP-1. The lysosomotropic antioxidant, cysteamine, inhibited all of the above changes. Targeting lysosomes with antioxidants, such as cysteamine, to prevent the intralysosomal oxidation of LDL might be a novel therapy for atherosclerosis.
我们已经表明，聚集的 LDL 通过巨噬细胞内吞作用并在溶酶体中被氧化还原活性铁氧化。我们现在研究的目的是确定 LDL 在溶酶体中的氧化是否会损害溶酶体功能，以及溶酶体靶向抗氧化剂是否可以预防这些改变。用 SMase（SMase-LDL）聚集的 LDL 导致人单核细胞衍生的巨噬细胞或 THP-1 巨噬细胞样细胞中的溶酶体脂质过氧化增加，如荧光探针 Foam-LPO 所示。溶酶体 LDL 氧化使溶酶体的 pH 值显著增加，如 LysoSensor Yellow/Blue 和 LysoTracker Red 所示。SMase-LDL 诱导细胞出现衰老样特性，如β-半乳糖苷酶染色和 p53 和 p21 的水平。炎症在动脉粥样硬化中起关键作用。SMase-LDL 处理增加了脂多糖诱导的 TNF-α、IL-6 和 MCP-1 的分泌。溶酶体靶向抗氧化剂如半胱胺可以抑制所有上述变化。用抗氧化剂如半胱胺靶向溶酶体以防止 LDL 在溶酶体中的内体氧化可能是动脉粥样硬化的一种新的治疗方法。
