Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Slides 29 38

54 views

Published on

SHAPE Society

Published in: Health & Medicine
  • Be the first to comment

  • Be the first to like this

Slides 29 38

  1. 1. Secretion and Regulation of ApoB48 by Primary Hamster Intestinal EnterocytesIntestinal Enterocytes B C LabeledApoB48(%control) LabeledApoB48(%control) 0 20 40 60 80 100 120 Total Cells Media Control MG132 P < 0.05 0 20 40 60 80 100 120 Total Cells Media Control Oleate P = 0.01 Cells Media 0 45 90 45 90 A Chase Time (min)
  2. 2. Cells Media Fructose-Fed Chow-Fed Chase Time (Min) 0 45 90 45 90 D Chase Time (Min) Chase Time (Min) 100 100 0 10 20 30 40 50 60 70 80 90 0 20 40 60 80 Total apoB 48 LabeledApoB48(%of0Time) LabeledApoB48(%of0Time) p= 0.003 p= 0.001 Secreted apoB 48 0 10 20 30 40 50 60 70 80 90 100 0 20 40 60 80 100 Chow-Fed Fructose-Fed E F Ex vivo evidence for oversecretion of intestinal apoB48 & Enhanced intracellular apoB48 stability in fructose- fed hamster enterocytes
  3. 3. In Vivo Production of TG & Intestinal ApoB48 in the Fasting State Time (min) 55 60 65 70 75 80 85 Sf>400TGconcentration (mmol/l) 0 1 2 3 4 Sf >400 after Triton WR1339 Time (min) 55 60 65 70 75 80 85 Sf>400ApoB48concentration (µg/ml) 140 160 180 200 220 240 260 280 Time (min) 55 60 65 70 75 80 85 Sf100-400TGconcentration (mmol/l) 0 1 2 3 Sf 100-400 after Triton WR1339 Time (min) 55 60 65 70 75 80 85 Sf100-400ApoB48concentration (µg/ml) 90 100 110 120 130 140 150 160 170 Triglyceridesecretion 0.0 0.2 0.4 0.6 0 1 2 3 ApoB48secretion 0 4 8 12 16 Triglyceridesecretion 0.0 0.1 0.2 0.3 ApoB48secretion 0 2 4 6p = 0.002 p = 0.01 p = 0.14 p = 0.59 A B DC
  4. 4. In Vivo Production of TG & Intestinal ApoB48 in the Postprandial State Time (min) 55 60 65 70 75 80 85 Triglyceridelevel(mmol/l) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Time (min) 55 60 65 70 75 80 85 ApoB48level(µg/ml) 80 90 100 110 120 130 140 150 Time (min) 55 60 65 70 75 80 85 Triglyceridelevel(mmol/l) 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Time (min) 55 60 65 70 75 80 85 ApoB48level(µg/ml) 50 60 70 80 90 100 Triglyceridesecretion(µmol/min) 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 Col 48: 0.07 Col 48: 0.06 Triglyceridesecretion(µmol/min) 0.00 0.02 0.04 0.06 0.08 0.10 Col 50: 0.08 Col 50: 0.09 0 1 2 3 ApoB48secretion(µg/min) 0 1 2 3 4 5 6 7 8 Col 52: 2.65 Col 52: 7.46 ApoB48secretion(µg/min) 0 1 2 3 4 5 6 7 8 Col 54: 3.85 Col 54: 7.26 Sf 100-400 after Triton WR1339 Sf >400 after Triton WR1339 A B C D p = 0.3 p = 0.003 p = 0.8 p = 0.007
  5. 5. 0 20 40 60 80 100 120 140 160 Fructose-Fed MTPProteinMass (%ofControl) Chow-Fed Fructose-Fed 0 20 40 60 80 100 120 0 0.5 1 1.5 2 2.5 3 3.5 MTP inhibitor (µM) ApoB48Secretion(%ofcontrol) Fructose-fed Chow-fed ∗ ∗ ∗ ∗ Chow-Fed p=0.006D E LabeledCholesterylEster (%ofControl) p= 0.002 0 50 100 150 200 250 Cellular p=0.001 Media B LabeledCholesterol (%ofControl) Chow-Fed Fructose-Fed 0 100 200 300 400 500 600 700 800 Cellular p=0.0018 p=0.0013A Media LabeledTriglyceride (%ofControl) Cellular 0 20 40 60 80 100 120 140 160 180 p=0.04 p=0.003 Media C Ex Vivo Evidence for Intestinal Overproduction of Lipoprotein Lipids and Increase MTP mass/activity
  6. 6. Fructose-Fed Chow-fed 0 10 20 30 40 50 60 70 80 Large CM Small CM VLDL LDL HDL p<0.05 p= 0.06 p<0.03 %ofTotalLabeledApoB48 A 0 20 40 60 80 100 120 140 CM apoB48 Total-apoB48 LabeledApoB48 (%ofFructose-fed) p<0.0007 p<0.01C 0 10 20 30 40 50 60 70 80 Particles< 1.006 Particles > 1.006 %ofTotalLabeledAPoB48 p<0.024 p<0.026 B 0 40 20 60 80 100 120 CM apoB48 Total apoB48 LabeledApoB48 (%ofFructose-fed) P=0.008 P=0.0001 DFasting Postprandial Density/Size Distribution of Intestinal Lipoproteins Evidence for Increased Number & Size
  7. 7. Increased De Novo Lipogenesis in FF Enterocytes Evidence that ApoB48 Secretion is Linked to the Rate of De Novo Lipogenesis 0 10 20 30 40 50 60 70 80 90 100 110 0 2 4 6 8 10 12 14 16 Cholesterol Fatty Acid Triglyceride LabeledLipid(%ascontrol) Cerulenin µg/ml 0 50 100 150 200 250 300 350 Chow-fed Fructose-fed LabeledFattyAcid(%ascontrol) 0 10 20 30 40 50 60 70 80 90 100 110 0 2 4 6 8 10 12 14 16 Cerulenin µg/ml LabeledSecretedApoB-48(%ascontrol) A C p= 0.002 Sensitivity of ApoB48 Secretion to Cerulenin Fatty Acid Synthesis Sensitivity of TG & FA Secretion to Cerulenin
  8. 8. 20 60 80 100 0 40 120 Chow-fed Fructose-fed (2 days) 0 20 40 60 80 100 120 Control Fructose (3mM ) 0 200 400 600 800 1000 enterocytes hepatocytes P < 0.01 LabeledApoB-48(%ofcontrol) LabeledApoB-48(%ofcontrol) Labeledcholesterol 0 50 100 150 200 250 300 350 400 450 enterocytes hepatocytes LabeledTriglyceride P < 0.0001 Acute Fructose Feeding or Exposure Does NOT Affect Intestinal ApoB48 Secretion [14 C] Fructose Incorporation into TG & Cholesterol Two-day Fructose Feeding In Vitro Incubation of Enterocytes with Fructose
  9. 9. Mechanisms of Intestinal Lipoprotein Overproduction in Insulin Resistant/ Hyperinsulinemic States Apical Surface Basolateral Surface FA monoglyceride FABP-FA FABP TG TG TG ApoB48 PL CE De Novo (FA) Insulin (??) TGdietary SOS Grb-2 IRS PI3-K p110 SHP-2 NCK PTKPTK β β α α IR PKB (Akt) SREBP1c FAS & ACC Glucose + FA MTP ERER GolgiGolgi Intestinal Enterocyte TG ApoB48 Lipoprotein Particles p85Proteasome Degradation
  10. 10. Acknowledgements Laboratory Group: Changiz Taghibiglou Mehran Haidari Steven Van Iderstine Wei Qui Taryne Chong Farhana Mahboob Biao Chen Leyla Mangaloglu Louisa Pontrelli Fariborz Rashid Rita Kohen Debbie Rudy Collaborators: Gary Lewis- Toronto Andre Carpentier- Sherbrooke Sven Olof Olofsson - Sweden Janet Sparks - Rochester, NY Raphael Cheung – Windsor Michel Tremblay – Montreal Denny Trinh - Toronto Funding: Heart & Stroke Foundation of Ontario Canadian Institutes of Health Research NSERC Hospital for Sick Children Merck-Frosst pfizer GlaxoSmithKline BBDC, University of Toronto

×