Week 5 part 2 Flashcards
Define Lipidomics
Subset of metabolomics, which focus on the study lipidome (complete collection of lipids in a cell, an organ, or a biological system)
What does research in lipidomics involve?
- precise identification of structures of cellular lipid species, including the number of atoms, the number and location of double bonds, core structures and head groups, individual fatty acid chains)
- Determine the interaction of individual lipid species with other lipids, proteins and metabolites in vivo
- Accurately quantifying individual lipid species for pathway analysis
- disclosing the nutritional or therapeutics status for prevention or therapeutic intervention
What is the Lipids Maps Structure Database (LMSD) i?
Relational database encompassing structures and annotations of biologically relevant lipids
From 02/04/2019, What does the LMSD contain?
43308 unique lipid structures
What are the 8 classes of lipids?
- Fatty Acyls [FA] (e.g. eicosanoids)
- Glycerolipids [GL] (e.g. Triglycerides)
- Glycerophospholipids [GP] (e.g. phosphatidylserine]
- Sphingolipids [SP] (e.g. Ceramides]
- Sterol Lipids [ST] (e.g. steroids)
- Prenol Lipids [PR] (e.g. Quinones)
- Saccharolipids [SL] (e.g. Acylaminosugars)
- Polyketides [PK] (e.g. Flavonoids)
What is the key technology for lipid species?
mass spectrometry
Why do Lipidologist possess a ‘‘biological intelligence’’?
allows them to interpret MS data in a manner that recognises what is likely or not likely to be the correct structure of a particular lipid species
What are the requirements for lipids?
lipids should be defined by both their class and their nominal mass (Da)
What are the various structural combinations of Lipid nomenclature?
- location of double bonds or attachment groups
- Attachment groups
- Head group
- Backbone
What are two lipids involved in energy storage?
diglyceride and triglyceride
What is the function of fat/triglyceride?
- energy store formed via fatty acid synthesis predominantly in liver
- stored mainly as fat in adipose tissues
What do cells with mitochondria have?
Lipoproteins
What are the two cell types that doesn’t use triglyceride directly for energy?
- Red blood cells due to absent mitochondria
2. cells in brain due to triglyceride not being able to cross blood brain barrie
What is used for energy during non-fed state?
- Ketoacids made from fat in liver
What lipids are insoluble in water and must be transported in association with proteins in the circulation?
- Cholesterol
2. Triglyceride
What is transported as triglyceride to avoid toxicity?
- large quantities of fatty acids from meals
What are lipoproteins?
complex particles that have a central hydrophobic core of non-polar lipids
e.g. cholesterol esters and triglyceride
What are plasma lipoproteins
7 classes based on:
- size
- lipid composition
- Apolipoproteins
What can Lipoproteins exist in?
5 major forms
What does 5 major forms of Lipoproteins contain?
- Triglycerides
- Phospholipids
- Cholesterol
- Proteins
What are the 5 major forms of Lipoprotein?
- Chlyomicrons
- VLDL
- Intermediate density lipoprotein (IDL)
- LDL
- HDL
What are Chylomicron?
Exogenous lipids are packaged by endoplasmic reticulum in small intestine epithelial cells then transported to blood
metabolised by muscle and adipose tissue by lipoprotein lipase
ULDL remnants are taken up by liver and enter endogenous lipoprotein pathway
What are VLDL
Endogenous triglyceride are packaged in hepatocytes and transported to muscle for energy or adipocytes for storage via circulation
What are IDL?
partially metabolised VLDL
What are LDL?
Metabolised product from IDL and transport cholesterol to liver
More susceptible to oxidation, which could result in an enhanced uptake by macrophages
What are HDL?
Transport of cholesterol to steroidogenic organs ( e.g. adrenals, ovary, testes) or to live for excretion in bile
Have anti-oxidant, anti-inflammatory, anti-thrombotic and anti-apoptotic properties
Enriched in cholesterol and phospholipid
Where are chylomicrons made by?
Intestine
involved in transport of dietary triglyceride to periperhal tissues and liver
What does a high fat meal lead to?
Formation of large chylomicron due to the increased amount of triglyceride being transported
What results in the formation of IDL particles which are enriched in cholesterol?
The removal of triglyceride from VLDL by muscle and adipose tissue
What are LDL partciles susceptible to?
- Oxidation
result in an enhanced uptake of macrophages
What does HDL play an important role in?
Reverse cholesterol transport from peripheral tissues to the liver
What are the characteristics of HDL particles?
- anti-oxidant
- Anti-inflammatory
- Anti-thrombotic
- Anti-apoptotic
- Inhibit atherosclerosis
What are HDL particles enriched in?
- Cholesterol
2. Phospholipids