National Institute for Health and Medical Research (INSERM), INSERM UMR 1166 ICAN, Paris, France; University of Pierre and Marie Curie-Paris 6, Paris, France; AP-HP, Groupe Hospitalier Pitié Salpétrière, Paris, France.
AP-HP, HUPS Hôpital de Bicêtre, Le Kremlin-Bicêtre, France; Lip(Sys)(2) Athérosclérose: homéostasie et trafic du cholestérol des macrophages, University Paris-Sud, University Paris-Saclay, 92296 Châtenay-Malabry. France.
Biochim Biophys Acta Mol Cell Biol Lipids. 2017 Sep;1862(9):890-900. doi: 10.1016/j.bbalip.2017.05.010. Epub 2017 May 18.
High-density lipoprotein (HDL) contains multiple components that endow it with biological activities. Apolipoprotein A-I (apoA-I) and surface phospholipids contribute to these activities; however, structure-function relationships in HDL particles remain incompletely characterised.
Reconstituted HDLs (rHDLs) were prepared from apoA-I and soy phosphatidylcholine (PC) at molar ratios of 1:50, 1:100 and 1:150. Oxidative status of apoA-I was varied using controlled oxidation of Met112 residue. HDL-mediated inactivation of PC hydroperoxides (PCOOH) derived from mildly pre-oxidized low-density lipoprotein (LDL) was evaluated by HPLC with chemiluminescent detection in HDL+LDL mixtures and re-isolated LDL. Cellular cholesterol efflux was characterised in RAW264.7 macrophages.
rHDL inactivated LDL-derived PCOOH in a dose- and time-dependent manner. The capacity of rHDL to both inactivate PCOOH and efflux cholesterol via ATP-binding cassette transporter A1 (ABCA1) increased with increasing apoA-I/PC ratio proportionally to the apoA-I content in rHDL. Controlled oxidation of apoA-I Met112 gradually decreased PCOOH-inactivating capacity of rHDL but increased ABCA1-mediated cellular cholesterol efflux.
Increasing apoA-I content in rHDL enhanced its antioxidative activity towards oxidized LDL and cholesterol efflux capacity via ABCA1, whereas oxidation of apoA-I Met112 decreased the antioxidative activity but increased the cholesterol efflux. These findings provide important considerations in the design of future HDL therapeutics. Non-standard abbreviations and acronyms: AAPH, 2,2'-azobis(-amidinopropane) dihydrochloride; ABCA1, ATP-binding cassette transporter A1; apoA-I, apolipoprotein A-I; BHT, butylated hydroxytoluene; CV, cardiovascular; EDTA, ethylenediaminetetraacetic acid; HDL-C, high-density lipoprotein cholesterol; LOOH, lipid hydroperoxides; Met(O), methionine sulfoxide; Met112, methionine 112 residue; Met86, methionine 86 residue; oxLDL, oxidized low-density lipoprotein; PBS, phosphate-buffered saline; PC, phosphatidylcholine; PL, phospholipid; PCOOH, phosphatidylcholine hydroperoxide; PLOOH, phospholipid hydroperoxide.
高密度脂蛋白 (HDL) 包含多种赋予其生物活性的成分。载脂蛋白 A-I (apoA-I) 和表面磷脂有助于这些活性；然而，HDL 颗粒的结构-功能关系仍不完全清楚。
采用摩尔比为 1:50、1:100 和 1:150 的载脂蛋白 A-I 和大豆磷脂酰胆碱 (PC) 制备再组装高密度脂蛋白 (rHDL)。通过 Met112 残基的控制氧化来改变 apoA-I 的氧化状态。通过 HPLC 结合化学发光检测在 HDL+LDL 混合物和再分离的 LDL 中评估 HDL 对源自轻度预氧化 LDL 的磷脂氢过氧化物 (PCOOH) 的失活作用。在 RAW264.7 巨噬细胞中表征细胞胆固醇流出。
rHDL 以剂量和时间依赖的方式失活 LDL 衍生的 PCOOH。rHDL 灭活 PCOOH 和通过 ABCA1 流出胆固醇的能力随着 apoA-I/PC 比例的增加而增加，与 rHDL 中的 apoA-I 含量成正比。apoA-I Met112 的控制氧化逐渐降低 rHDL 的 PCOOH 失活能力，但增加了 ABCA1 介导的细胞胆固醇流出。
增加 rHDL 中的 apoA-I 可增强其对氧化 LDL 的抗氧化活性和通过 ABCA1 的胆固醇流出能力，而 apoA-I Met112 的氧化则降低了抗氧化活性，但增加了胆固醇流出。这些发现为未来 HDL 治疗的设计提供了重要考虑。非标准缩写和缩写：AAPH，2,2'-偶氮双（-脒基丙烷）二盐酸盐；ABCA1，ATP 结合盒转运蛋白 A1；apoA-I，载脂蛋白 A-I；BHT，丁基羟基甲苯；CV，心血管；EDTA，乙二胺四乙酸；HDL-C，高密度脂蛋白胆固醇；LOOH，脂质氢过氧化物；Met(O)，蛋氨酸亚砜；Met112，蛋氨酸 112 残基；Met86，蛋氨酸 86 残基；oxLDL，氧化低密度脂蛋白；PBS，磷酸盐缓冲盐水；PC，磷脂酰胆碱；PL，磷脂；PCOOH，磷脂氢过氧化物；PLOOH，磷脂氢过氧化物。
