King's College London British Heart Foundation Centre, School of Cardiovascular Medicine and Sciences, United Kingdom (S.A.B., E.D., R.L., K. Theofilatos, K. Takov, M.M.).
Institute for Pathophysiology, University Hospital Essen, West German Heart and Vascular Center, Germany (K.S., G.H.).
Circ Res. 2021 Nov 12;129(11):1039-1053. doi: 10.1161/CIRCRESAHA.121.319272. Epub 2021 Oct 4.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) circulates in a free and lipoprotein-bound form, yet the functional consequence of the association between PCSK9 and high-density lipoprotein (HDL) remains unexplored.
This study sought to interrogate the novel relationship between PCSK9 and HDL in humans.
Comparing lipoprotein and apolipoprotein profiles by nuclear magnetic resonance and targeted mass spectrometry measurements with PCSK9 levels in the community-based Bruneck (n=656) study revealed a positive association of plasma PCSK9 with small HDL, alongside a highly significant positive correlation between plasma levels of PCSK9 and apolipoprotein-C3, an inhibitor of lipoprotein lipase. The latter association was replicated in an independent cohort, the SAPHIR study (n=270). Thus, PCSK9-HDL association was determined during the postprandial response in two dietary studies (n=20 participants each, 8 times points). Peak triglyceride levels coincided with an attenuation of the PCSK9-HDL association, a loss of apolipoprotein-C3 from HDL and lower levels of small HDL as measured by nuclear magnetic resonance. Crosslinking mass spectrometry (XLMS) upon isolated HDL identified PCSK9 as a potential HDL-binding partner. PCSK9 association with HDL was confirmed through size-exclusion chromatography and immuno-isolation. Quantitative proteomics upon HDL isolated from patients with coronary artery disease (n=172) returned PCSK9 as a core member of the HDL proteome. Combined interrogation of the HDL proteome and lipidome revealed a distinct cluster of PCSK9, phospholipid transfer protein, clusterin and apolipoprotein-E within the HDL proteome, that was altered by sex and positively correlated with sphingomyelin content. Mechanistically, HDL facilitated PCSK9-mediated low-density lipoprotein receptor degradation and reduced low-density lipoprotein uptake through the modulation of PCSK9 internalisation and multimerisation.
This study reports HDL as a binder of PCSK9 and regulator of its function. The combination of -omic technologies revealed postprandial lipaemia as a driver of PCSK9 and apolipoprotein-C3 release from HDL.
前蛋白转化酶枯草溶菌素 9（PCSK9）以游离形式和脂蛋白结合形式循环，但 PCSK9 与高密度脂蛋白（HDL）之间的关联的功能后果仍未得到探索。
本研究旨在探讨人类 PCSK9 与 HDL 之间的新关系。
通过比较社区为基础的布伦瑞克研究（n=656）中的脂蛋白和载脂蛋白图谱与核磁共振和靶向质谱测量的 PCSK9 水平，发现血浆 PCSK9 与小 HDL 呈正相关，同时血浆 PCSK9 水平与脂蛋白脂肪酶抑制剂载脂蛋白 C3 呈高度显著正相关。后一种关联在独立队列 SAPHIR 研究（n=270）中得到了复制。因此，在两项饮食研究（n=20 名参与者，每个研究 8 个时间点）中，在餐后反应期间确定了 PCSK9-HDL 关联。甘油三酯水平峰值与 PCSK9-HDL 关联减弱、载脂蛋白 C3 从 HDL 丢失以及核磁共振测量的小 HDL 水平降低同时发生。对分离的 HDL 进行交联质谱（XLMS）鉴定 PCSK9 为潜在的 HDL 结合伴侣。通过凝胶排阻色谱法和免疫分离法证实了 PCSK9 与 HDL 的关联。对冠心病患者（n=172）分离的 HDL 进行定量蛋白质组学分析，发现 PCSK9 是 HDL 蛋白质组的核心成员。对 HDL 蛋白质组和脂质组的综合分析揭示了 HDL 蛋白质组中 PCSK9、磷脂转移蛋白、载脂蛋白 E 和簇蛋白的一个独特簇，该簇受性别影响，并与神经鞘磷脂含量呈正相关。从机制上讲，HDL 促进了 PCSK9 介导的低密度脂蛋白受体降解，并通过调节 PCSK9 的内化和多聚化减少了低密度脂蛋白的摄取。
本研究报道 HDL 是 PCSK9 的结合物，并调节其功能。组学技术的结合揭示了餐后脂血症是 PCSK9 和载脂蛋白 C3 从 HDL 释放的驱动因素。
