What Is Phospholipids
Phospholipids refers to lipids containing phosphate groups and belong to the class of complex lipids, which can be divided into two main categories: glycerophospholipids and sphingophospholipids, which are composed of glycerol and sphingosine, respectively. Phospholipids are amphipathic molecules, with one end being a hydrophilic head containing nitrogen or phosphate, and the other end being a hydrophobic (lipophilic) long hydrocarbon chain. Due to this structure, phospholipid molecules arrange themselves with hydrophilic ends close to each other and hydrophobic ends close to each other, forming lipid bilayers along with proteins, glycolipids, cholesterol, and other molecules to constitute the structure of the cell membrane.
What Is Phospholipidomics
In 2008, Jan and colleagues from the University of Bremen, Germany, proposed the concept of phospholipidomics. Phospholipidomics is an emerging discipline that involves the systematic analysis of the entire phospholipid profile. It is a branch of lipidomics that aims to identify key phospholipid biomarkers involved in metabolic regulation by comparing changes in phospholipid metabolic networks under different physiological conditions. Ultimately, phospholipidomics aims to uncover the mechanisms of phospholipids in various biological processes.
Electrospray Ionization-Mass Spectrometry (ESI-MS) is the core research technique in the field of phospholipidomics, enabling high-resolution, high-sensitivity, and high-throughput analysis of phospholipids. With the development of liquid chromatography-mass spectrometry (LC-MS), phospholipidomics has shown promising applications in the identification of phospholipid biomarkers for diseases, disease diagnosis, discovery of drug targets and lead compounds, and the study of drug action mechanisms. It holds significant importance for biomedical research and has broad prospects for application.
Classification of Phospholipids
Phospholipids possess a characteristic structure, consisting of a hydrophilic head (containing amino or alcohol groups) linked to a hydrophobic tail (composed of fatty acid chains) through a phosphate group. Phospholipids can be classified into two main categories based on the different alcohol components: glycerophospholipids and sphingolipids (SM).
Glycerophospholipids are the most abundant type of phospholipids in organisms. Apart from forming biological membranes, they also serve as components of bile and membrane surfactants. Additionally, they participate in cell membrane recognition and signal transduction of proteins. Glycerophospholipids can be further categorized into six classes based on the different polar heads: phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylglycerol (PG), and phosphatidic acid (PA). Within each class, there are numerous structurally similar subclasses distinguished by different fatty acid chains, such as plasmalogens and lysolecithins. Cardiolipin (CL) is a diphosphatidylglycerol, a complex phospholipid widely present in the inner mitochondrial membrane. It can regulate the activity of oxidative phosphorylation enzymes and plays a crucial role in maintaining mitochondrial function and membrane integrity.
Sphingolipids, also known as sphingomyelins, are widely distributed in various biological tissues, especially in high quantities within brain tissue.
Functions of Phospholipids
Phospholipids serve multiple critical physiological functions, and extensive research has shown that disruptions in phospholipid metabolism can lead to various diseases, such as diabetes, obesity, atherosclerosis, coronary heart disease, Alzheimer's disease, brain injuries, cancer, fatty liver, and Barth syndrome, among others. Consequently, the study of phospholipids and their metabolic processes in living organisms has become a key focus in understanding disease mechanisms, diagnosis, treatment, and pharmaceutical research.
In order to obtain a comprehensive profile of phospholipids in biological samples, better elucidate the mechanisms of phospholipid substances within the organism, and identify biomarkers or metabolic patterns associated with diseases, scientists have made phospholipid analysis a prominent area of research. This approach aims to provide a scientific basis for early disease diagnosis and further advance our understanding of the roles played by phospholipids in biological systems.
Phospholipid Mass Spectrometry Analysis Methods
Traditional analysis methods are complex and have low sensitivity, such as HPLC, TLC, and GC-MS. When using GC-MS analysis, phospholipids need to be hydrolyzed and derivatized first, and it can only provide information about the fatty acyl chains, lacking precise determination of the phospholipid structure.
Although the structural diversity of phospholipids increases the analytical challenges, with the advancement of modern analytical techniques, there are now various feasible methods available, such as shotgun lipidomics and High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS). Electrospray Ionization-Mass Spectrometry (ESI-MS) offers advantages of simple sample preparation, high resolution, and easy automation, making it particularly suitable for rapid, sensitive, and high-throughput qualitative and quantitative analysis of phospholipid mixtures. The hyphenation of liquid chromatography and mass spectrometry has significantly advanced phospholipidomics, with ESI-MS as the core technology, enhancing the separation and identification of phospholipids with high throughput, sensitivity, and efficiency. Moreover, multidimensional mass spectrometry techniques have shown new progress in phospholipidomics research.
Shotgun lipidomics provides high sensitivity, speed, and ease of automation, but it has some limitations when analyzing phospholipid isomers. The hyphenation of liquid chromatography and mass spectrometry effectively improves the deficiencies in shotgun lipidomics, such as ion suppression effects on low-abundance phospholipids and the inability to accurately analyze isomers.
Currently, liquid chromatography-mass spectrometry (LC-MS) has become the most widely used technology in phospholipid analysis.
Workflow for Phospholipid LC-MS Analysis Platform
Application of Phospholipid Mass Spectrometry Analysis
With the advancement of phospholipidomics research, the functions of phospholipids within living organisms will be further revealed. The application of mass spectrometry technology to analyze changes in the phospholipid profile in biological systems and identify potential biomarkers will find widespread applications in the following areas:
Early diagnosis: By identifying reliable biomarkers and correlating them with prognosis, mass spectrometry analysis can provide a basis for selecting appropriate treatment plans.
Disease monitoring: Monitoring changes in the types or quantities of phospholipid biomarkers can reflect the progression of diseases.
Drug development: Based on insights into the pathogenesis, mass spectrometry analysis can provide potential targets for drug design.
Studying the overall differences in phospholipid metabolism between normal and diseased states, identifying disease-specific phospholipid biomarkers, and combining them with enzyme research can lead to in-depth investigations of metabolic pathways or pathogenic mechanisms, ultimately leading to the discovery of effective diagnostic and therapeutic approaches.
It is foreseeable that as phospholipidomics research continues to progress, our understanding of the structure and mechanisms of phospholipids will deepen. The accuracy of diagnosing diseases and monitoring disease progression at the level of phospholipid metabolism will further improve. Through the regulation of the phospholipid metabolic network within the body, it is hoped that the treatment of diseases can be achieved.
Our Phospholipid LC-MS Analysis Platform
Currently, a reliable and reproducible method using highly sensitive LC-MS/MS platform for the identification and quantification of diverse phospholipid species in different sample types has been established by the scientists at Creative Proteomics, which can satisfy the needs of academic and industrial study in your lab.
Platform
- LC-MS/MS
Summary
Identification and quantification of diverse phospholipids by mixed organic solvent extraction in cells or tissue. These phospholipid species can be measured in a Phospholipid Panel by targeted LC-MS/MS or by shotgun approaches.
Sample Requirement
- Normal Volume: 200 uL plasma, 20 mg tissue, 1e7 cells
- Minimal Volume: 50uL, 5 mg tissue, 6e6 cells
Report
- A full report including all raw data, MS/MS instrument parameters and step-by-step calculations will be provided (Excel and PDF formats).
- Analytes are reported as uM or ug/mg (tissue), and CV's are generally<10%
| Phospholipid Classes | Bioactive Phospholipids |
|---|---|
| Phosphatidic acids (PA) | PAF (platelet activating factor) |
| Bismonoacylglycerophosphates (BMP) | Lyso-PA |
| Phosphatidylglycerols (PG) | Lyso-PS |
| Phosphatidylethanolamines (PE) | Lyso-PC |
| Phosphatidylcholines (PC) | S-1-P (Sphingosine-1-Phosphate) |
| Phosphatidylinositols (PI) | |
| Phosphatidylserines (PS) | |
| Cardiolipins (CL) | |
| Sphingomyelins (SM) |
| Phospholipids | ||
|---|---|---|
| Phosphatidic acid (PA) | Phosphatidylethanol (PEtOH) (or phosphatidylbutanol, PBuOH) | Phosphatidylglycerol (PG) |
| Phosphatidylcholine (PC) | Platelet-activating factor (PAF) | Phosphatidylethanolamine (PE) |
| Phosphatidylinositol (PI) | Monophosphorylated phosphatidylinositol (PIP) | Bisphosphorylated phosphatidylinositol (PIP2) |
| Trisphosphorylated phosphatidylinositol (PIP3) | Phosphatidylserine (PS) | Cardiolipin (CL) |
| The corresponding lyso-phospholipids (LPL) | The corresponding ether lipids | |
Ordering Procedure:
*If your organization requires signing of a confidentiality agreement, please contact us by email.
Staffed by experienced biological scientists, Creative Proteomicscan provide a wide range of services ranging from the sample preparation to the lipid extraction, characterization, identification and quantification. We promise accurate and reliable analysis, in shorter duration of time! You are welcome to discuss your project with us.
Reference
- Sen Yang, Jingyuan Xue, Cunqi Ye.Protocol for rapid and accurate quantification of phospholipids in yeast and mammalian systems using LC-MS.STAR Protocols. 2022