Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway.
Department of Biochemistry and Molecular Biology, Biomedical Center, Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101, Reykjavik, Iceland.
Sci Rep. 2020 Mar 11;10(1):4528. doi: 10.1038/s41598-020-61352-0.
Dysregulated cholesterol homeostasis promotes the pathology of atherosclerosis, myocardial infarction and strokes. Cellular cholesterol is mainly regulated at the transcriptional level by SREBP2, but also through uptake of extracellular cholesterol from low density lipoproteins (LDL) via expression of LDL receptors (LDLR) at the cell surface. Identification of the mechanisms involved in regulation of these processes are thus key to understand the pathology of coronary artery disease. Here, we identify the large and poorly characterized BEACH domain protein Neurobeachin-like (NBEAL) 1 as a Golgi- associated protein required for regulation of cholesterol metabolism. NBEAL1 is most abundantly expressed in arteries. Genetic variants in NBEAL1 are associated with decreased expression of NBEAL1 in arteries and increased risk of coronary artery disease in humans. We show that NBEAL1 regulates cholesterol metabolism by modulating LDLR expression in a mechanism involving interaction with SCAP and PAQR3 and subsequent SREBP2-processing. Thus, low expression of NBEAL1 may lead to increased risk of coronary artery disease by downregulation of LDLR levels.
胆固醇稳态失调会促进动脉粥样硬化、心肌梗死和中风等疾病的发生。细胞内胆固醇主要通过 SREBP2 在转录水平上进行调节,但也可以通过细胞表面 LDL 受体(LDLR)表达从低密度脂蛋白(LDL)摄取细胞外胆固醇。因此,鉴定参与这些过程调节的机制是理解冠状动脉疾病病理学的关键。在这里,我们发现大型且特征不明确的 BEACH 结构域蛋白神经海滩样蛋白 1(NBEAL1)是高尔基体相关蛋白,对于胆固醇代谢的调节是必需的。NBEAL1 在动脉中表达最丰富。NBEAL1 中的遗传变异与动脉中 NBEAL1 表达降低以及人类患冠状动脉疾病的风险增加有关。我们表明,NBEAL1 通过调节 LDLR 的表达来调节胆固醇代谢,这一机制涉及与 SCAP 和 PAQR3 的相互作用以及随后的 SREBP2 加工。因此,NBEAL1 表达水平降低可能会通过下调 LDLR 水平增加患冠状动脉疾病的风险。