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بسم الله الرحمن الرحيم

بسم الله الرحمن الرحيم. Glycolipids. By. Amr S. Moustafa, M.D.; Ph.D. Outlines. Overview and Functions Structure and Types Synthesis and Degradation Sphingolipidosis. Overview. Essential component of membranes Abundant in nervous tissue Extra-nervous tissue: e.g., Receptors for

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بسم الله الرحمن الرحيم

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  1. بسم الله الرحمن الرحيم

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

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

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

  8. Galactocerbroside

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

  10. Gangliosides GM2

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

  17. CONT’D Sphingolipidosis

  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 O2 Peroxidase (GSH) Parent Prostaglandin : PGH2

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

  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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