Macrophages are essential innate immune cells and form our first line of immune defense. Also known as professional phagocytes, macrophages interact and take up various particles, including lipids. Defective lipid handling can drive excessive lipid accumulation leading to foam cell formation, a key feature of various cardiometabolic conditions such as atherosclerosis, non-alcoholic fatty liver disease, and obesity. At the same time, intracellular lipid storage and foam cell formation can also be viewed as a protective and anti-lipotoxic mechanism against a lipid-rich environment and associated elevated lipid uptake. Traditionally, foam cell formation has primarily been linked to cholesterol uptake via native and modified low-density lipoproteins. However, other lipids, including non-esterified fatty acids and triacylglycerol (TAG)-rich lipoproteins (very low-density lipoproteins and chylomicrons), can also interact with macrophages. Recent studies have identified multiple pathways mediating TAG uptake and processing by macrophages, including endocytosis and receptor/transporter-mediated internalization and transport. This review will present the current knowledge of how macrophages take up different lipids and lipoprotein particles and address how TAG-rich lipoproteins are processed intracellularly. Understanding how macrophages take up and process different lipid species such as TAG is necessary to design future therapeutic interventions to correct excessive lipid accumulation and associated co-morbidities.

中文翻译：

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巨噬细胞对三酰甘油的摄取和处理：从脂肪酸到脂蛋白


巨噬细胞是必不可少的先天免疫细胞，构成了我们的第一道免疫防御线。巨噬细胞也称为专业吞噬细胞，它们相互作用并吸收各种颗粒，包括脂质。有缺陷的脂质处理会导致脂质过度积累，导致泡沫细胞形成，这是各种心脏代谢疾病（如动脉粥样硬化、非酒精性脂肪肝和肥胖）的关键特征。同时，细胞内脂质储存和泡沫细胞形成也可以被视为针对富含脂质的环境和相关脂质摄取升高的保护和抗脂毒性机制。传统上，泡沫细胞的形成主要通过天然和修饰的低密度脂蛋白与胆固醇摄取有关。然而，其他脂质，包括非酯化脂肪酸和富含三酰甘油 （TAG） 的脂蛋白（极低密度脂蛋白和乳糜微粒），也可以与巨噬细胞相互作用。最近的研究确定了介导巨噬细胞 TAG 摄取和加工的多种途径，包括内吞作用和受体/转运蛋白介导的内吞和转运。本综述将介绍巨噬细胞如何吸收不同脂质和脂蛋白颗粒的当前知识，并讨论富含 TAG 的脂蛋白如何在细胞内加工。了解巨噬细胞如何吸收和处理不同的脂质种类（如 TAG）对于设计未来的治疗干预措施以纠正过度脂质积累和相关合并症是必要的。