Brain Lipids
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Transcript of Brain Lipids
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BrainLipids
Dr. Mohammed Vaseem
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Classification of lipids
Simple Lipids
Compound Lipids Derived Lipids
LIPIDS
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Simple lipids of interest in the brain
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Compound Lipids
Esters of fatty acids with various alcohols along with an additional group.
a. Phospholipids b. Glycolipids
Simple lipid + Additional group = Compound Lipids
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a. Phospholipids: Lipids with phosphate groupGlycerophospholipids Sphingophospholipids
Glycerol
Sphingosine
Compound Lipids
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Glycerol
Glycerophospholipids
Phospholipids
SATURATED
Unsaturated
BASE
Phosphatidyl choline (also called Lecithin) : Base in this is choline
Phosphatidyl serine (cephalin) : Base in this is serine
Phosphatidyl ethanolamine : Base is ethanolamine
GlycerolFattyacidPhosphateBase
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Phospholipids
Sphingopohospholipids
Sphingosine
Base
Sphingosine instead of glycerolFattyacidPhosphateBase
Ex: Ceramide (Sphingosine + FA)
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b. Glycolipids: Cerebrosides
Gangliosides : Glycolipids with one or more N- acetyl neuraminic acid (sialic acid) in addition to other sugars
Compound Lipids
Sphingosine Carbohydrate
Fattyacid
Cer – Glucose – Galactose – N Acetyl Galactosamine - Galactose
SIALIC ACID
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Galactocerebroside (Ceramide + galactose)
Cerebroside with two or more carbohydrates attached are referred to as Globosides
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Ganglioside
GM1 ganglioside
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Plasmalogens
Constitute 7-10% of phospholipids in the brain
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Lipid storage disorders
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Myelin from a biochemical perspective
Myelin sheath is a greatly extended and modified plasma membrane wrapped around the nerve axon in a spiral fashion Oligodendrocytes in the CNS Schwann cells in the PNS
Responsible for the rapid impulse transmission by “Saltatory impulse transmission”
Also components are involved in various cell signalling processes
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Structure of Myelin sheath
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Schmidt – Laterman cleft
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Characteristic composition of Myelin40% water Dry mass
70-80% - Lipid 15 -30% - Protein
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Composition of CNS Myelin and Brain
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Myelin Proteins
Myelin Basic ProteinsProteolipid protein 60 – 80 % of
total protein
Except MBP none is water soluble
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PLP (Proteolipid protein)
Folch – Lees proteinTetraspan protein, MW - ~ 30000Structural Protein Involved in oligodendrocyte
migration and maturationModulates Vesicle transport and
Extracellular matrix interactions
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MBP
7 alternately spliced isoforms
Localized on cytoplasmic side of membrane
Stabilization of the myelin structure
May also be involved in process extension of neural cells
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Other proteins associated with myelin are
2’ 3’ cyclic mucleotide 3’ phosphodiesterases
P – type glycoproteinsEnzymesNeurotransmitter receptors – mAch,
NMDA etc
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Diseases related to MyelinMultiple Sclerosis
Guilliane – Barre syndrome
Lipid storage disorders (Sphingolipidoses)