A Central Role of MG53 in Metabolic Syndrome. and Type-2 Diabetes

Transcription

1 A Central Role of MG53 in Metabolic Syndrome and Type-2 Diabetes Yan Zhang, Chunmei Cao, Rui-Ping Xiao Institute of Molecular Medicine (IMM) Peking University, Beijing, China

2 Accelerated Aging in China Percentage of people over 6 (%) Y -15Y > 6Y Source:

3 Serious Unmet Medical Needs: Explosion of NCDs Diabetes 114 Mn in China Possible Asian DM phenotype with lower BMI onset, dissimilar glucose metabolism Hypertension 25 Mn in China: high incidence of complications Stroke mortality in China/India is 16/125 vs. US 47, 1k population/year

4 Metabolic Syndrome: A Clinical Constellation Abdominal Obesity Hypertension MS US 25% China, 15% Dyslipidemia Proinflammatory Prothrombotic Insulin Resistance Type-2 Diabetes The IDF consensus worldwide definition of the metabolic syndrome (25)

5 MS Increases the Risk of CVD and T2D Scott M. Grundy, NATURE REVIEWS DRUG DISCOVERY 5:295-39, 26

6 Common Soil of MS: Insulin Resistance Obesity Dyslipidemia Insulin Resistance Hyperglycemia Hypertension Lancet, 365: , 25

7 Glucose Metabolism Blood Glucose skeletal muscle accounts for 7-9% of insulin-stimulated glucose disposal Nature Medicine, 1: , 24 7

8 MG53: A Key Player in Insulin Resistance Insulin MG53 Hypertension Coronary Heart Disease Stroke Diabetes

9 MG53 is Specifically Expressed in Cardiac and Skeletal Muscles Brain Liver Spleen Lung Kidney Pancreas Intestine Stomach Heart M. Skeletal M. Testis White fat 1 White fat 2 Brown fat MG53 Northern blot of MG53 in wt mice. 1: subcutaneous adipose tissue; 2: visceral adipose tissue. 9

10 Upregulation of MG53 in Rodent Models with Metabolic Disorders A. Chow HFD Mouse Rat Lean db/db WKY SHR MG53 GAPDH B. MG53 protein (fold of control) Song et al., nature, 213

11 Transgenic Overexpression of MG53 Is Sufficient to Induce Obesity a b MG53 GSK3β Heart wt Skeletal muscle Heart wt Skeletal muscle mg53 TG Lung Brain Hypothalamus Liver Intestine Kidney Visceral fat Testis mg53 TG Body weight (g) c wt mg53 TG Age (weeks)

12 Transgenic Overexpression of MG53 Triggers Severe Insulin Resistance a. b. Glucose (mg/dl) Glucose (% of baseline) Glucose (min) Insulin (min) wt mg53 TG

13 Overexpression of MG53 Causes Hypertension and Metabolic Disorders a Blood pressure (mmhg) Systolic Diastolic b Cholesterol (mg/dl) c Insulin (ng/ml) wt mg53 TG

14 Transgenic Overexpression of MG53 Does Not Cause Skeletal Muscle Atrophy wt mg53 TG 5 µm Cross-sectional area (µm 2 ) 2 1 Weight (g).2.1. wt mg53 TG

15 Upregulation of MG53 Leads to Diabetic Cardiomyopathy Insulin MG53 Diabetic cardiomyopathy is the major cause of death (5%) in patients with diabetes Hypertension Coronary Heart Disease Stroke Diabetes Common Soil: Insulin Resistance

16 Overexpression of MG53 Causes Cardiac Hypertrophy and Ventricular Dilation A WT Mg53 TG C WT Mg53 TG B Heart weight (g)

17 Overexpression of MG53 Leads to Myocardial Lipid Accumulation WT mg53 TG

18 MG53 Ablation Attenuates HFD-induced Obesity A. B. A. Body weight (g) # # # # # # # wt Chow mg53-/- Chow wt HFD mg53-/- HFD wt Chow mg53-/- Chow wt HFD mg53-/- HFD Age (weeks) 1 cm

19 Mg53 deficiency Prevents HFD-induced Glucose Intolerance Glucose (mg/dl) # # # # # wt Chow wt HFD mg53-/- Chow mg53-/- HFD Glucose (% of baseline) Glucose (min) # # # # # Insulin (min)

20 MG53 Ablation Attenuates HFD-induced Hypertension Blood pressure (mmhg) wt Chow mg53-/- Chow Systolic Diastolic wt HFD mg53-/- HFD

21 MG53 Ablation blocks HFD-induced Metabolic Disorders A. B. Blood glucose (mg/dl) wt Chow mg53-/- Chow Fast wt HFD mg53-/- HFD Fed Insulin (ng/dl) C. Cholesterol (mg/dl) Triglyceride (mg/dl)

22 MG53 Attenuates HFD-induced Fatty Liver wt Chow wt mg53-/- mg53-/- HFD HE staining of Liver

23 MG53 Deficiency Prevents HFD-induced Pancreatic Dysfunction wt Chow mg53-/-chow wt mg53-/- wt HFD mg53-/-hfd Chow HFD Insulin (% of baseline) # 15 3 Glucose (min)

24 Insulin Signaling Nature. 414: , 21.

25 MG53 Blocks Muscle Insulin Signaling a Insulin p-irβ t-irβ - wt mg53 TG b p-irβ (fold of wt) Insulin - + NS - + t-ir (fold of wt) 1 wt mg53 TG py-irs1 t-irs1 p-akt t-akt py-irs1 (fold of wt) Insulin - + NS - + t-irs1 (fold of wt) 1 MG53 GAPDH p-akt (fold of wt) 1 5 Insulin - + NS - + t-akt (fold of wt) 1

26 MG53 Blocks Insulin-induced Glucose Uptake in C2C12 Myotubes and Cardiac Myocytes A B Ad-GFP Ad-MG53 2-NBDG uptake (fold of Control) 2 1 Glucose uptake (fold of control) insulin min insulin 3 min insulin min insulin 3 min

27 MG53 Ablation Restores Insulin Sensitivity in Mice on HFD Chow HFD wtchow mg53-/- Chow wt HFD mg53-/- HFD Insulin p-irs1 t-irs1 wt mg53-/ wt mg53-/ p-irs1 (fold of wt Chow) Insulin p-akt t-akt p-gsk3β t-gsk3 p-akt (fold of wt Chow) Insulin MG53 GAPDH p-gsk3β (fold of wt Chow) Insulin

28 Progression and Outcomes of MS Grundy SM., Journal of the American College of Cardiology, 26

29 Different T2D Profile in China vs USA USA China 48% 14% 21% 9% 8% 17% 27% 56% T2DM T2DM + Hypertension T2DM + Obesity T2DM + Hypertension + Obesity DiBonaventura, The burden of the Complicated T2DM Patient in China

30 Tracking Insulin Sensitivity in Multiple Organs 3

31 Muscle Insulin Resistance Is the Earliest Defect in mg53 TG mice a Insulin p-akt t-akt Skeletal muscle wt mg53 TG wt Liver mg53 TG + Visceral fat wt mg53 TG MG53 b p-akt/t-akt (fold of WT) GAPDH w age wt mg53 TG Insulin Skeletal muscle Liver Visceral fat

32 Aberrant Muscle Insulin Signaling Precedes Systemic Insulin Resistance in Mice on HFD for 1 week Chow HFD Insulin p-akt t-akt MG53 GAPDH Skeletal muscle Chow HFD Insulin p-akt t-akt MG53 GAPDH Liver Visceral fat Chow HFD Insulin p-akt t-akt MG53 β-actin p-akt/t-akt (fold of control) 1 5 Chow HFD Insulin p-akt/t-akt (fold of control) 2 1 Insulin p-akt/t-akt (fold of control) 8 4 Insulin Chow HFD

33 Systemic Insulin Resistance in mg53 TG mice at 38 weeks of age Insulin p-akt t-akt MG53 GAPDH p-akt/t-akt (fold of wt) Skeletal muscle wt mg53 TG Liver wt mg53 TG w age Visceral fat wt mg53 TG wt mg53 TG Insulin Skeletal muscle Liver Visceral fat

34 Systemic Insulin Resistance-induced by HFD (35 Weeks) Skeletal muscle Liver Visceral fat Insulin p-akt t-akt wt Chow HFD mg53-/- mg53-/-wt wt mg53-/ Chow HFD wt mg53-/-wt mg53-/ Chow HFD wt mg53-/ p-akt/t-akt Insulin p-akt/t-akt Insulin 6 p-akt/t-akt t Insulin

35 Posttranslational Downregulation of Both IR and IRS1 in MS Models a c IR β protein (fold of control) IRS1 protein (fold of control) b IR mrna (fold of control) d IRS1 mrna (fold of control)

36 Is MG53 an E3 Ligase? MG53 RING B-box Putative coiled-coil PRY SPRY TRIM SPRY Ring: E3 ligase? B-box: no clear function Coiled-coil: oligomerization SPRY: protein interaction

37 MG53 E3 Ligase Targets IR and IRS1 for Ubiquitin-dependent Degradation a c Chow HFD IP: IRβ IB: ubiquitin IRβ (Ub) n 95 kda IP: IRβ IB: ubiquitin IRβ (Ub) n 95 KDa Lysate IRβ MG53 IRβ MG53 Lysa te b IRS1 (Ub) n d Chow HFD IRS1 (Ub) n IP: IRS1 IB: ubiquitin 17 kda IP: IRS1 IB: ubiquitin 17 KDa Lysate IRS1 MG53 Lysate IRS1 MG53

38 Sequence Analysis of MG53 N-terminus RING B-box Putative coiled-coil PRY SPRY C14A Homo sapiens: Mus musculus: Xenopus laevis: C C CH C C C C RING (lacking 1-56 aa) Zn 2+ Zn 2+ Ring finger cross-brace motif 38

39 Ring Finger Domain Is Required for MG53- mediated IR and IRS1 Ubiquitination a b Flag-FL-MG Flag- RING Flag-C14A IR-Myc HA-Ub IP: Myc IB: HA IRβ (Ub) n 95 Kd Flag-FL-MG Flag- RING Flag-C14A IRS1-Myc HA-Ub IP: Myc IB: HA IRS1 (Ub) n 17 Kd Lysate IB: Flag IB: Myc Lysate IB: Flag IB: Myc

40 Central Role of E3 Ubiquitin Ligase MG53 in Insulin Resistance and Metabolic Syndrome Insulin receptor (IR) PM Glucose uptake GSK3 Akt IRS1 PI3K Ub Ub Ub Ub Ub Ub Ub Ub Proteosome MG53 E2 Ub UbUbUbUb Degradation of IR & IRS1 Glycogen synthesis Dietary factors Hypertension Genetic defects Stress Insulin Resistance, MS, Obesity, T2D and CVD

41 Summary 1. MG53 expression is universally elevated in various rodent, nonhuman primate models and humans with insulin resistance and metabolic disorders. 2. Transgenic overexpression of MG53 in mice is sufficient to cause severe insulin resistance and metabolic syndrome. 3. Upregulation of MG53 is indispensable for dietinduced insulin resistance and metabolic disorders. 4. Thus, upregulation of MG53, a novel E3 ligase, is both necessary and sufficient to target insulin resistance and resultant metabolic syndrome.

42 Ongoing Translational Research Man (disease detection, prevention, intervention and possible reversal; human tissue bank) Nonhuman Primate disease models Rodent Disease Models (KO, KI, TG models, in vivo physiology and pathology, cell signaling circuitries) Molecules (medical genetics; high-throughput gene sequencing and protemomics; bioinformatics)

43 NHP Model of Spontaneous Metabolic Syndrome

44 Insulin Resistance in MS Monkeys Glucose (mmol/l) MetS Control Insulin (μu/ml) Time (min) Time (min)

45 Upregulation of MG53 in NHPs and Humans with MS NHP Human Control MS Control MS MG53 MG53 GAPDH GAPDH MG53 protein (fold of control) 2 1 MG53 protein (fold of lean) 3 2 1

46 Human Population Genetic Study

47 Target Validation: MG53 as A Pomising Target for Metabolic and CV Diseases Discovery Development

48 Discovery to Delivery IP Portfolios University Healthcare Delivery

49 Team Efforts

50 Thank You!