Regulation of the Arachidonic Acid Cascade and PAF Metabolism in Reproductive Tissues
Murray D. Mitchell in Eicosanoids in Reproduction, 2020
Glycerophospholipid degradation in mammalian tissue is primarily catalyzed by the action of phospholipases, as illustrated in Figure 2. With the exception of phosphatidylinositol, most glycerophospholipids are degraded via phospholipase A enzymes. The phosphatidylinositol pathway employs phospholipase C; the products of this reaction are inositol phosphate(s) and diacylglycerol. The role of the inositol polyphosphates and diacylglycerol as second messengers and the relationship of Ca2+ to signal transduction and protein kinase C activity have recently been reviewed.31,32 More recently, a role for phospholipase D, which has been purified from mammalian tissues,33 has been implicated in the generation of phosphatidic acid, which may subsequently function as a second messenger.34
Cell Structure and Functions
Malgorzata Lekka in Cellular Analysis by Atomic Force Microscopy, 2017
The major glycerophospholipids assembled in the endoplasmic reticulum (ER) are phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidic acid. In addition, the ER synthesizes ceramides, galactosylceramide, cholesterol, and ergosterol. Both the ER and lipid droplets participate in steryl ester and triacylglycerol synthesis. The Golgi lumen is the site of synthesis of sphingomyelin, complex glycosphingolipids, and yeast inositol sphingolipid. Phosphatidylcholine is also synthesized in the Golgi, and may be coupled to protein secretion at the level of its diacylglycerol precursor. Approximately 45% of the phospholipids (mostly phosphatidylethanolamine, phosphatidic acid, and cardiolipin) in mitochondria are autonomously synthesized by this organelle. The inner membrane of late endosomes produces mostly bis(mono-acylglycero) phosphate (BMP).
Annexes
Claude Leray in Dietary Lipids for Healthy Brain Function, 2017
Phospholipids are mostly glycerophospholipids; therefore, they contain one molecule of glycerol esterified with two fatty acids, most frequently different from each other, and a “head group.” This polar head group gives an originality to phospholipids; thus, for the most important, it is a phosphocholine for phosphatidylcholine, a phosphoserine for phosphatidylserine, and a phosphoethanolamine for phosphatidylethanolamine. They are the main lipid constituents of cellular membranes and are therefore present in all meats, but they also are in the form of fat depots in milk and egg yolk. Plants also contain these phospholipids, but their content remains low (up to 0.2%), greatly reducing their nutritional value except when consumed in the form of supplements prepared from seeds. Their interest lies in their polar head and their fatty acid content (Leray 2015).
Mechanistic exploration of Yiqi Liangxue Shengji prescription on restenosis after balloon injury by integrating metabolomics with network pharmacology
Published in Pharmaceutical Biology, 2023
Tianshi Mao, Long Xie, Yanqiong Guo, Xiang Ji, Jie Wan, Xiaoyun Cui, Qian Fan, Wei Liu, Shuai Wang, Wenbo Han, Qian Lin, Wenhao Jia
Glycerophospholipid metabolism was proven to be relevant to vascular inflammation and injury. In this pathway, there are multiple enzymatic lipid metabolites, such as phosphatidylcholine (PC) and lyso-phosphatidylcholine (LPC), which play vital roles in inflammation and lipid oxidation (Lu et al. 2017). LPC, together with a proinflammatory factor, is the key constituent of oxidized low-density lipoprotein (ox-LDL). Under oxidative stress, the enzyme phospholipase A2 (PLA2) is activated. PC is converted into LPC via catalysis and degradation by PLA2. LPC shows a proatherogenic effect by promoting EC apoptosis and VSMC proliferation and migration to the endothelium and transforming lipids into foam cells (Schmitz and Ruebsaamen 2010). Interestingly, TNF signaling pathway could enhance the conversion of PC to LPC during glycerophospholipid metabolism (Su et al. 2022). In the model group, the level of LPC (16:1/0:0) increased, and that of PC (15:0/15:0) decreased. After treatment, the above two metabolites recovered to normal levels. It is thus suggested that YQLXSJ may inhibit VSMC proliferation and migration by decreasing PLA2 activity and decreasing LPC production through glycerophospholipid metabolism.
Liposomes for drug delivery: review of vesicular composition, factors affecting drug release and drug loading in liposomes
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
Shantanu Pande
Phospholipids are categorised into glycerophospholipids, and sphingomyelins based on the alcohol groups present in their structures [9]. The most used glycerophospholipids in formation of liposomes are Phosphatidylcholine (PC), Phosphatidyl ethanolamine (PE), Phosphatidylserine (PS), Phosphatidylinositol (PI) and Phosphatidylglycerol (PG) [7, 8]. Hydrogenated Soy Phosphatidylcholine (HSPC) a glycerophospholipid is a saturated phospholipid which is hydrogenated and possesses greater physicochemical stability compared to unsaturated lipids [11]. The degree of unsaturation, fatty acid side chains and phase transition temperature of phospholipids determine the stability of liposomes [12]. An important property of phospholipids especially in the formation of liposomes in the phase transition temperature (TC). The phase transition temperature of phospholipids is the temperature at which the state of phospholipids changes from gel to liquid crystalline phase [9, 13]. The phospholipids which are tightly packed in the bilayer region of liposomes start loosening up and become more permeable when the phase transition temperature of phospholipids is reached [13]. This change causes more empty spaces between the phospholipids thereby aiding in the film formation step of liposome preparation [13]. The phase transition temperature of HSPC is 53 °C and phospholipids with high transition temperature provide increased physical stability at room temperature [9, 14].
Systematic review on activity of liposomal encapsulated antioxidant, antibiotics, and antiviral agents
Published in Journal of Liposome Research, 2022
Reshna K. R, Preetha Balakrishnan, Sreerag Gopi
Phospholipid contains two major categories including glycerophospholipids and sphingolipids (categorized into sphingomyelin and glycolipid). The glycerophospholipids are considered as a backbone of liposome. The chemical structure of glycerophospholipids consists of a hydrophilic head group and a hydrophobic side chain. Different glycerophospholipids are obtained as a result of head group variation, for example, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidic acid (PA), phosphatidylglycerol (PG), and cardiolipin (CL). Decreased nonpolar moieties with varying lengths produce a wide range of different glycerophospholipids, such as dimyristoyl, dipalmitoyl, and distearoyl PC, among others. Furthermore, the type of bond formed between glycerol and aliphatic chains (ether or ester) results in the formation of distinct glycerophospholipids.
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