Why is HDL Cholesterol Low in People with Insulin Resistance and Type 2 Diabetes Mellitus?

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1 Why is HDL Cholesterol Low in People with Insulin Resistance and Type 2 Diabetes Mellitus? Henry Ginsberg, MD Columbia University College of Physicians and Surgeons

2 Henry Ginsberg: Disclosures Research Grant; Significant; Merck, Genzyme/Sanofi, AstraZeneca. Consultant/Advisory Board; Modest; Pfizer, Roche, Kowa, Sanofi, Isis, Novartis. Consultant/Advisory Board; Significant; Merck.

3 Patient #1 60 yr old man Post-MI x 3 yrs Hypertension- treated BMI 30 HbA1c 6.9% Fasting Insulin 25 uu/ml TC 230 LDL 138 TG 300 HDL 32

4 Lipids in Diabetics and Nondiabetics: Framingham Offspring Men Nondiabetics Diabetic % HDL-C<35 Total-C 240+ LDL-C 160+ TG 250+ HDL-C<35 TG 250+ Siegel RD et al. Metabolism. 1996;45:

5 Lipids in Diabetics and Nondiabetics: Framingham Offspring Women % Nondiabetics Diabetic HDL-C<35 Total-C 240+ LDL-C 160+ TG 250+ HDL-C<35 TG Siegel RD et al. Metabolism. 1996;45:

6 Mechanisms Relating Insulin Resistance and Dyslipidemia Fat Cells Liver FFA IR TG Apo B VLDL VLDL Insulin

7 Mechanisms Relating Insulin Resistance and Dyslipidemia Fat Cells Liver FFA CE IR TG Apo B VLDL VLDL (CETP) TG HDL (hepatic lipase) Apo A-1 Insulin Kidney

8 Patient #1 60 yr old man Post-MI x 3 yrs Hypertension- treated BMI 30 HbA1c 6.9% Fasting Insulin 25 uu/ml TC 230 LDL 138 TG 300 HDL 32 Of course, it is high TG, CETP mediated transfer, etc etc

9 But.Patient #2 60 yr old man Post-MI x 3 yrs Hypertension- treated BMI 30 HbA1c 6.9% Fasting Insulin 25 uu/ml TC 200 LDL 138 TG 150 HDL 32

10 And what about patient #1 on fibrate? 60 yr old man Post-MI x 3 yrs Hypertension- treated BMI 30 HbA1c 6.4% Fasting Insulin 30 uu/ml TC 212 LDL 138 TG 200 HDL 34

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12 Lipid Measurement (mg/dl) HTG/Low HDL-C (N=941) All Others (N= 4548) Cholesterol Triglyceride* LDL-Cholesterol HDL-Cholesterol (Men) HDL-Cholesterol (Women) Data are mean + sem (95% confidence limits) * Median value

13 HDL-C Decrease with Fenofibrate: HTG/Low HDLC = mg/dl All Others = - 8.9mg/dl Increase with Fenofibrate: HTG/Low HDLC = + 4.5mg/dl All Others = + 2.3mg/dl

14 Why do people with insulin resistance or type 2 diabetes have low HDL cholesterol levels? Maybe it is not so simple: can we learn anything from mouse models?

15 Triglyceride (mg/dl) TG Increase (mg/dl) Weight (grams) Glucose (mg/dl) Insulin (ng/ml) ApoB/BATless mice are obese, insulin resistant, and hypertg due to increased VLDL secretion Siri P, Candela N, Zhang YL, Ko C, Plasma Eusufzai glucose S, Ginsberg levels were HN, not Huang different, LS but J Biol Chem. 2001;276:46064 mice without BAT were hyperinsulinemic Weight increased steadily over 22 weeks * * 30 ** WT BATless ApoB B/BATless WT BATless ApoB B/BATless Plasma 0 triglycerides were increased with VLDL secretion is increased in apob expression Time (weeks) the apob/batless mouse * p<0.05 vs B & WT ** p < 0.05 vs other 3 groups ** * WT BATless ApoB ApoB/BATless 0 ApoB ApoB/BATless

16 Total Cholesterol HDL cholesterol levels were reduced in apob/batless mice 200 VLDL IDL + LDL HDL ( m g/fraction) Fraction No. (0.5 ml/fraction)

17 Hepatic insulin resistance is sufficient to produce dyslipidemia and susceptibility to atherosclerosis Biddinger, Hernandez-Ono et al; Cell Metab : LIRKO Severe Hepatic Insulin Resistance insulin glucose

18 apob100 secretion (% flox cpm / timepoint) apob100 Secretion is Increased in Male LIRKO on a Western-Type Diet p=0.001 p=0.033 n = 7-9 / group Flox LIRKO Flox LIRKO 60 min 120 min

19 Triglycerides (mg/dl) TG increase (mg/dl) * Triglyceride Secretion is Decreased in LIRKO vs Floxed Mice on a Western-type Diet * p < LIRKO n = 5 Flox n = 4 * * * * p < 0.05 Time (min) 0 Male Flox Male LIRKO Age: 14 to 17 wks *

20 LIRKO mice have low HDL cholesterol levels

21 PI3K knockout has low HDL cholesterol

22 Restoration of insulin signaling via AKT restores HDL cholesterol

23 ug cholesterol/fraction Lirko mice had a lower HDL cholesterol (20 week female mice ) Flox LIRKO FloxP (n=7), LIRKO (n=5)

24 Lirko mice had a lower plasma apoai level (16 week month male mice) Floxp(n=6) Lirko(n=6)

25 ug cholesterol/fraction AKT1&2DKO(fast) WT DKO Leavens et al Cell Metab 2009;10:

26 Serum apoai levels decreased in AKT1&2DKO mice WT AKT1&2DKO

27 Isolated loss of hepatic insulin signaling results in lower levels of HDL C and plasma apoai: What is the mechanism? Work done by Jing Liu, PhD Poster 506: Friday morning

28 Acute knockdown of hepatic insulin receptor Inslr floxp on chow 8-9 wks Day 0 Day 3 Day 6 Day 11 Injection of Ad-Cre(n=6) and Ad-LacZ(n=6) X X X X: sacrifice FPLC and western for Insulin receptor

29 Adenovirus-mediated acute knockdown of hepatic insulin receptor Day 3 Day 6 Day11 Ad-Cre Ad-LacZ Ad-Cre Ad-LacZ Ad-Cre Ad-LacZ IR- β β -actin

30 ug/fraction Knockdown of hepatic IR decreases HDL cholesterol Ad-Lacz Ad-Cre 6 days after Ad-LacZ (n=3) and Ad-Cre(n=3) injection

31 Microarray Clustering results lipid metabolism process

32 Knockdown of hepatic Insr decreased Dio1 mrna *

33 Deiodinases Dio1 is a single transmembrane protein in the plasma membrane with a cytosolic catalytic site. It is mainly expressed in liver, kidney, thyroid. Dio2 is located in ER membrane. It exists in brain, muscle, brown adipose tissue, pituitary & placenta. Deiodinase type 3: fetal and placenta; white adipose tissue

34 Deiodinase type I conversion of the prohormone thyroxine (T 4 ) to the active hormone triiodothyronine (T 3 ) through the removal of an iodine atom on the outer ring

35 qpcr result confirmed microarray data * * * * *

36 Restoration of insulin signaling LIRKO mice in chow 12 wks Injection of CA-AKT(n=4) and Ad-LacZ(n=4) 12 days Collection of the blood and liver

37 Restoration of insulin signaling reverts DIO1 Levels in LIRKO mice *

38 Dio1 knockout mouse has reduced levels of apoai mrna

39 Treated LIRKO mice with Ad-Dio1 and Ad-GFP LIRKO mice in chow 16 wks 0 day Injection of Ad-Dio1(n=3) and Ad-GFP( n=3) 5 days 12 days Collection of the blood Collection of the blood and liver

40 Liver Dio1 mrna increased after Ad-Dio1 administration *

41 ug cholesterol/fraction HDL cholesterol went up in Lirko after Ad- Dio1 treatment GFP-2 GFP-1 Dio1-6 Dio

42 apoai from FPLC fraction Fraction Ad-GFP Ad-Dio1

43 apoai mrna tended to increase in Lirko mice after Ad-Dio1 treatment

44 Knockdown of insulin receptor in McA cells using sirna McA-RH 7777 cells were placed in 24 wells plate Mission sirna from sigma N-TER Nanoparticle sirna Transfection System 30nm SiRNA serum free pre-incubation 48 hrs

45 Knockdown of Insr reduced Dio1 and apoai mrna levels in McA cells * * *

46 Knockdown of Insr or Dio1 reduced apoai promoter activity in McA cells * *

47 Ad-Dio1 reversed apoai promoter activity in HepG2 cells treated with sirna-insr * *

48 Insulin signaling regulates human apoai promoter activity by acting on the B site Schematic representation of human apoa I promoter constructs. A and C contain HREs which bind nuclear receptor superfamily. Element B binds C/EBP. Claudel.et al JCI, 2002

49 Insulin signaling regulates human apoai promoter activity by acting on the B site * * Schematic representation of human apoa I promoter constructs. A and C contain HREs which bind nuclear receptor superfamily. Element B binds C/EBP. Claudel.et al JCI, 2002

50 Summary LIRKO mice have very low levels of HDL cholesterol and low levels of apoai in the absence of high TG (and CETP); PI3K ko mice and Akt ko mice also have low HDL levels Restoration of insulin signaling increases HDL levels LIRKO mice have very low levels of Dio1 mrna as well as low levels of AI (and several other lipoprotein related genes) RNA levels Restoration of insulin signaling increases Dio1 expression Expression of Dio1 in LIRKO was associated with increases in HDL cholesterol and plasma AI levels, and a trend toward increased AI mrna levels Knockdown of insulin receptors in McA or HepG2 cells reduces expression of Dio1 and apoai mrna Knockdown of Dio1 in McA or HepG2 cells reduces expression of an apoai-luciferase reporter construct. Dio1 knockout mouse has reduced levels of apoai mrna

51 Hypothesis Altered hepatic insulin signaling plays a role in the low HDL cholesterol and apoai levels seen in people with insulin resistance/t2dm via reduced levels of deiodinase 1. Further elucidation of the molecular pathway between deiodinase 1 and the apoai gene could provide a new target for treating low HDL in this large group of people.