Mammalian lipid droplets (LDs) are specialized cytosolic organelles consisting of a neutral lipid core surrounded by a membrane made up of a phospholipid monolayer and a specific population of proteins that varies according to the location and function of each LD. Over the past decade, there have been significant advances in the understanding of LD biogenesis and functions. LDs are now recognized as dynamic organelles that participate in many aspects of cellular homeostasis plus other vital functions. LD biogenesis is a complex, highly-regulated process with assembly occurring on the endoplasmic reticulum although aspects of the underpinning molecular mechanisms remain elusive. For example, it is unclear how many enzymes participate in the biosynthesis of the neutral lipid components of LDs and how this process is coordinated in response to different metabolic cues to promote or suppress LD formation and turnover. In addition to enzymes involved in the biosynthesis of neutral lipids, various scaffolding proteins play roles in coordinating LD formation. Despite their lack of ultrastructural diversity, LDs in different mammalian cell types are involved in a wide range of biological functions. These include roles in membrane homeostasis, regulation of hypoxia, neoplastic inflammatory responses, cellular oxidative status, lipid peroxidation, and protection against potentially toxic intracellular fatty acids and lipophilic xenobiotics. Herein, the roles of mammalian LDs and their associated proteins are reviewed with a particular focus on their roles in pathological, immunological and anti-toxicological processes.

哺乳动物脂滴 (LD) 是一种特殊的胞质细胞器，由中性脂质核心组成，该核心被磷脂单层和特定蛋白质群组成的膜包围，这些蛋白质群根据每个 LD 的位置和功能而变化。在过去的十年中，人们对 LD 生物发生和功能的理解取得了重大进展。LD 现在被认为是参与细胞稳态和其他重要功能的许多方面的动态细胞器。LD 生物发生是一个复杂的、高度调控的过程，组装发生在内质网上，尽管基础分子机制的各个方面仍然难以捉摸。例如，目前尚不清楚有多少酶参与 LD 中性脂质成分的生物合成，以及如何协调该过程以响应不同的代谢线索以促进或抑制 LD 的形成和周转。除了参与中性脂质生物合成的酶之外，各种支架蛋白在协调 LD 形成中也发挥着作用。尽管缺乏超微结构多样性，但不同哺乳动物细胞类型中的 LD 涉及广泛的生物学功能。这些包括在膜稳态、缺氧调节、肿瘤炎症反应、细胞氧化状态、脂质过氧化以及针对潜在有毒的细胞内脂肪酸和亲脂性异生物质的保护中的作用。本文综述了哺乳动物 LD 及其相关蛋白的作用，特别关注它们在病理、免疫和抗毒理学过程中的作用。