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Glycolipids By Amr S. Moustafa, M.D.; Ph.D. Outlines Overview and Functions Structure and Types Synthesis and Degradation Sphingolipidosis.

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Presentation on theme: "Glycolipids By Amr S. Moustafa, M.D.; Ph.D. Outlines Overview and Functions Structure and Types Synthesis and Degradation Sphingolipidosis."— Presentation transcript:

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2 Glycolipids By Amr S. Moustafa, M.D.; Ph.D.

3 Outlines Overview and Functions Structure and Types Synthesis and Degradation Sphingolipidosis

4 Overview  Essential component of membranes  Abundant in nervous tissue  Extra-nervous tissue: e.g., Receptors for Cholera toxins Diphtheria toxins Viruses

5  Regulation of growth & development  Very antigenic: Blood group antigen Embryonic antigen Tumor antigen  Cell transformation Overview CONT’D

6 Sphingolipids: Structure and Types Ceramide = Sphingosine + fatty acid Sphingomyelin = Ceramide + Phosphorylcholine Cerebrosides = Ceramide + Monosaccharides Gangliosides = Ceramide oligosaccharides + NANA Globoosides = Ceramide + Oligosaccharides

7 Neutral Glycosphingolipids Globosides = Ceramide Oilgosaccharides Cerebrosides = Ceramide monosaccharides Galactocerbrosides = Ceramide + Galactose Glucocerbrosides = Ceramide + Glucose Lactosylceramide = Cer-Glc-Gal Forssman antigen = Cer-Glc-(Gal) 2 -(GalNac) 2

8 Galactocerbroside

9 Acidic Acidic Glycosphingolipids Negatively charged at physiological pH 1.Gangliosides: Most complex Ganglion cells Ceramide oligosaccharides + NANA 2. Sulfatides: Nerve tissue and kidneys Cerbrosides + Sulfated Gal

10 Gangliosides G M2

11 Sulfate donor: PAPS

12 Sulfatides Galactocerbroside 3-sulfate

13 Sphingolipids’ Synthesis

14 Sphingolipids’ Degradation Lysosomal hydrolytic enzymes Last on, First off Defective: Total or partial Sphingolipidosis

15  Synthesis (Normal); Degradation (Defective)  Substrate accumulates in organs  Progressive, early death  Phenotypic and genotypic variability  Autosomal recessive, Except Fabry (X-linked)  Rare, Except Ashkenazi Jewish

16 Sphingolipidosis  Measure enzyme activity Cultured fibroblasts or peripheral leukocytes Cultured amniocytes (prenatal)  Histologic examination  DNA analysis  Replacement Therapy: Recombinant human enzyme  Bone marrow transplantation: Gaucher disease Diagnosis: Treatment: CONT’D

17 Sphingolipidosis CONT’D

18 Niemann - Pick Disease

19 Gaucher Disease

20 Prostaglandins Eicosanoids (20 C): Prostaglandins (PG) Thromboxanes (TX) Leukotrienes (LT) PG Vs Hormones: All cells Local acting & Not stored Short half-life Plasma membrane & nuclear receptors

21 Prostaglandin’S Synthesis Dietary precursor: Linoleic acid 18:2 (9, 12) Immediate precursor: Arachidonic acid 20:4 (5, 8,11,14) Prostaglandin endoperoxide synthase: Microsomal enzyme Two Catalytic activities: Fatty acid cyclooxygenase (COX), 2 O 2 Peroxidase (GSH) Parent Prostaglandin : PGH 2

22 Prostaglandin’S Synthesis CONT’D

23 COX Isoenzymes COX-1: Constitutive Most tissues Important for: Integrity of gastric mucosa Renal homeostasis Platelet aggregation

24 COX Isoenzymes COX-2 Inducible Limited No. of tissues Stimulus: Products of inflammatory & immune cells Mediates: Inflammatory response: Pain, Redness & Swelling Fever of infection CONT’D

25 COX Inhibitors Cortisol (Steroid): Selective COX-2 (-) Phospholipase A2 (-) NSAIDS: Both COX-1 and –2 (-) Side effects: Gastric, Renal & Clotting Low-dose Asprin therapy Celecoxib: Selective COX-2 (-)

26 Prostaglandin’S Functions


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