Konishi Tomokazu, Takahashi Yoko
Graduate School of Bioresource Sciences, Akita Prefectural University, Akita, Japan.
Division of Food Function Research, Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan.
PLoS One. 2018 Feb 20;13(2):e0192955. doi: 10.1371/journal.pone.0192955. eCollection 2018.
Although lipoproteins are conventionally separated into a few classes using density gradient centrifugation, there may be a much higher number of physical classes that differ in origin or phase. Comprehensive knowledge of the classes of lipoproteins is rather limited, which hinders both the study of their functions and the identification of the primary causes of related diseases. This study aims to determine the number of classes of lipoproteins that can be practically distinguishable and identify the differences between them. We separated rat serum samples by gel filtration. The elution was continuously monitored for triglyceride (TG), cholesterol, and protein, and fractionated for further SDS-PAGE and immunological detection of apoprotein A-I (ApoA1) and apoprotein B (ApoB). The elution patterns were analyzed using a parsimonious method, i.e., the estimation of the least number of classes. Ten classes were recognized that contained different amounts of TG and cholesterol, as well as a unique protein content. Each of the classes contained much more protein than that observed previously, especially in low-density lipoproteins (LDL) classes. In particular, two major antiproteases formed complexes with specific classes of LDL; because these classes exclusively carry cholesterol and antiproteases, they may lead to the progression of atheroma by supplying materials that enlarge fatty streaks and protecting thrombi from enzymatic digestion. The separated classes may have specific biological functions. The attribution of protein species to certain classes will help understand the functions. A distinction among lipoprotein classes may provide important information in the field of vascular pathology.
尽管传统上使用密度梯度离心法将脂蛋白分为几类，但可能存在更多起源或相不同的物理类别。目前对脂蛋白类别的全面了解相当有限，这既阻碍了对其功能的研究，也妨碍了对相关疾病主要病因的识别。本研究旨在确定实际可区分的脂蛋白类别数量，并识别它们之间的差异。我们通过凝胶过滤法分离大鼠血清样本。连续监测洗脱液中的甘油三酯（TG）、胆固醇和蛋白质，并进行分馏以便进一步进行SDS-PAGE以及载脂蛋白A-I（ApoA1）和载脂蛋白B（ApoB）的免疫检测。使用一种简约方法分析洗脱模式，即估计最少的类别数量。识别出了十个类别，它们含有不同量的TG和胆固醇以及独特的蛋白质含量。每个类别所含的蛋白质都比之前观察到的要多得多，尤其是在低密度脂蛋白（LDL）类别中。特别地，两种主要的抗蛋白酶与特定类别的LDL形成复合物；由于这些类别专门携带胆固醇和抗蛋白酶，它们可能通过提供扩大脂肪条纹的物质并保护血栓免受酶消化而导致动脉粥样硬化的进展。分离出的类别可能具有特定的生物学功能。将蛋白质种类归属于某些类别将有助于理解其功能。脂蛋白类别的区分可能会在血管病理学领域提供重要信息。
