Understanding epigenetics: The potential rationale for BET - - PowerPoint PPT Presentation

▶
understanding epigenetics
SMART_READER_LITE
LIVE PREVIEW

Understanding epigenetics: The potential rationale for BET - - PowerPoint PPT Presentation

Oct 19, 2022 251 likes •587 views

Understanding epigenetics: The potential rationale for BET inhibition in management of CVD August 25, 2018 Munich, Germany Jorge Plutzky, MD Director, Preventive Cardiology Cardiovascular Division Brigham and Womens Hospital Harvard

slide-1
SLIDE 1

Jorge Plutzky, MD

Director, Preventive Cardiology Cardiovascular Division Brigham and Women’s Hospital Harvard Medical School Boston, Massachusetts

Understanding epigenetics: The potential rationale for BET inhibition in management of CVD

August 25, 2018 Munich, Germany

slide-2
SLIDE 2

Physiology Pathology

Coordinated Programs In Cardiometabolic States?

  • Fit
  • Normotensive
  • Insulin sensitivity
  • Less inflammation
  • Longevity
  • Central obesity
  • Diabetes
  • Hypertension
  • Inflammation
  • Alzheimer’s Disease
  • Cancer

+ +

  • Gene A

Gene C Gene J Gene X Gene Z

slide-3
SLIDE 3

Physiology CV Disease

Coordinated Programs In Cardiometabolic States?

  • Fit
  • Normotensive
  • Lower Triglycerides
  • Higher HDL
  • Insulin sensitivity
  • Less inflammation
  • Endothelial function
  • Longevity
  • Central obesity
  • Diabetes
  • Hypertension
  • Hypertriglyceridemia
  • Low HDL
  • Insulin resistance
  • Inflammation
  • Endothelial dysfunction
  • Coagulation
  • Myocardial injury

+ +

  • Gene A

Gene C Gene J Gene X Gene Z

Modulating key proximal transcription factors

slide-4
SLIDE 4

Energy Balance

RXR PPAR

slide-5
SLIDE 5

Energy Balance Obesity Dyslipidemia Diabetes Atherosclerosis

Lipids: Triglycerides (Fatty Acids) Glucose

RXR PPAR

Inflammation

slide-6
SLIDE 6

PPARs and Gene Regulation

PPARs in Transcriptional Regulation

slide-7
SLIDE 7

NF-kB

Hemodynamics Cytokines Lipids AngII AGEs

Collins, Cybulsky JCI 2001

A key integrator

  • f inflammation

and atherosclerosis

Inflammatory targets Matrix LPS

slide-8
SLIDE 8

PPARs and Gene Regulation

PPARs in Transcriptional Regulation Challenges in

  • Store vast genetic material in nucleus
  • Access specific genetic stretches

to enable transcription

slide-9
SLIDE 9

2 nm 30 nm 300 nm 700 nm 1400 nm

10,000 fold decrease in size

slide-10
SLIDE 10

Heterochromatin Euchromatin Transcription impeded Transcription Possible

Transcription Factors Transcription Factor Access

slide-11
SLIDE 11

CHROMOSOME FIBRE

DNA

NUCLEOSOME EPIGENETIC CODE chromatin fibre

Plutzky, El Assam, Circ Res, 2016

histone mark

slide-12
SLIDE 12

chromatin fibre histone mark

Plutzky, El Assam, Circ Res, 2016

acetylases, methylases phosphylases… deacetylases, demethylases dephosphylases… CHROMOSOME FIBRE NUCLEOSOME EPIGENETIC CODE

DNA

slide-13
SLIDE 13

chromatin fibre histone mark

Plutzky, El Assam, Circ Res, 2016

Acetylated lysines: BETs CHROMOSOME FIBRE

DNA

NUCLEOSOME EPIGENETIC CODE

slide-14
SLIDE 14

Physiology

Coordinated Programs In Cardiometabolic States?

  • Fit
  • Normotensive
  • Low TG/High HDL
  • Insulin sensitivity
  • Less inflammation
  • Endothelial function
  • Longevity

Gene J Gene Z

Epigenetics: BETs

Gene X

Master Transcription Factors Promoters Response elements mRNA Protein Enhancers

  • Central obesity
  • Diabetes
  • Hypertension
  • High TG/ Low HDL
  • Inflammation
  • Endothelial dysfunction
  • Coagulation
  • Myocardial injury

CV Disease

slide-15
SLIDE 15

Bromodomains

  • Structural motif (110 aa)
  • Interacts with acetylated lysines on histones
  • ~50 bromodomain-containing protein family

Bromodomain and Extra-Terminal Domain (BETs): Sub-family of proteins containing tandem bromodomains

1 74-185 345-457 632-710 801

BD 1 BD 2 E T

BRD2

1 34-145 307-419 562-640 726

BD 1 BD 2 E T

BRD3

1 58-159 349-461 600-678 1362

BD 1 BD 2 E T

BRD4

1 27-138 268-380 500-578 947

BD 1 BD 2 E T

BRDT*

slide-16
SLIDE 16

BET Proteins: Integral to Transcription Complex Assembly Along Gene Body

16

BET Protein 4 (BRD4)

Nature Reviews Mol Cell Biology 13, 543-547 Bradner, Nature 2010

BET Protein BET Inhibitor BET Inhibitor Selectivity

slide-17
SLIDE 17

Current Issues in Epigenetics/BETs: Super Enhancers

slide-18
SLIDE 18

Cell States: Transformation

Health Disease Differentiation Activation Adaptation Therapeutic?

Programs that define cell state

Maladaptive Pathologic Epigenetics BETs

slide-19
SLIDE 19

Rest Inflammation Endothelium

Cell State Transitions Organ: functional, dynamic Interface: Circulation + Organs Transducer Cell States

slide-20
SLIDE 20

Cell State Transitions

Rest Inflammation

Endothelium

Transcriptional Programs Rapid Multiple stimuli: Physical, chemical Essential: Host defenses Reset Pathologic Chromatin Remodeling BET Epigenetic Readers Super-Enhancers Cell States

slide-21
SLIDE 21

DIABETES Hyperglycemia AGEs Dyslipidemia Inflammation

Modified, Reddy, Natarajan, Epigenetics: Development & Disease, Subcellular Biochemistry 61, p435, 2013

Epigenetic Readers: BETs

NFkB

Genetics Exposures : Cig HTN Maternal- Fetal Diet Cell States

slide-22
SLIDE 22

Pressure Overload: BET Bromodomains Mediate Transcriptional Pause Release In Heart Failure

Cell 154: 569-582, 2013

Anand, Brown, Plutzky, Bradner, Haldar et al

Transverse Aortic Constriction

Cell States

slide-23
SLIDE 23

BET bromodomain inhibition significantly decreases LDLr -/- atherosclerosis

Oil Red O Mac3 CD4 VCAM1

VEH JQ1

VEH JQ1

2 4 6

VEH JQ1

% Lesion Area

*

  • 12 Weeks of HC/HF Diet
  • JQ1 50mg/kg, IP daily

Mol Cell, 2013

Brown, Plutzky et al

slide-24
SLIDE 24

Crosslink protein to DNA binding sites in living cells or tissue: Harvest cells and fragment DNA Enrich for protein-bound DNA fragments with antibodies Massively parallel DNA sequencing

Chromatin Immunoprecipitation coupled with deep sequencing: ChIP-Seq

Myocardium Endothelium

slide-25
SLIDE 25

TNF-a induces BRD4 recruitment to specific EC enhancers, enabling execution of the inflammatory NFkB transcriptional program

VCAM1 p65

  • TNFa

+ TNFa BRD4

  • TNFa

+ TNFa

Start site

slide-26
SLIDE 26

chr17:29,622,217 TNFa gained SE chr17:29,571,987 CCL2 10.0 10.0 BRD4 ChIP-Seq TNFa (-) p65 ChIP-Seq TNFa (-) 10.0 10.0 TNFa (+) TNFa (+) 15.0

rpm/bp rpm/bp

15.0

rpm/bp

RNA Pol II ChIP-Seq TNFa (-) TNFa (+) 10kb H3K4me3 ChIP-Seq TNFa (-) 3.5 3.5 TNFa (+)

rpm/bp

H3K27ac ChIP-Seq TNFa (-) 3.0 3.0 TNFa (+)

rpm/bp

Chemokine CCL2

TNF-a induces BRD4 recruitment to specific EC enhancers, enabling execution of the inflammatory NFkB transcriptional program

slide-27
SLIDE 27

Dynamic, rapid remodeling of super-enhancers in Ecs directs a broad, canonical pro-atherosclerotic program

CCL2 SOX18 TNFa lost SEs TNFa gained SEs n=152 n=124 VCAM1 Change in BRD4 Log2 TNFa (+) vs. TNFa (-)

S up er฀ en han cer regi

  • n s

i n E C s ran k ed by chan ge i n B R D 4 s i gn al

100 200 300 400 500 ฀5 5 SELE

slide-28
SLIDE 28

Apabetalone Reduces Atheroma in Aorta of ApoE-/- Mice

28 WK 8

HF Diet

WK 19 High Fat (42% kcal) Diet Animal Arrival

Necropsy

WK 9 Chow Chow: TD 2016 +/- apabetalone WK 33

Chow Diet

PlaceboApabetalone (150 mg/kg)

 of -40% (p<0.045)

Plaque/whole area (%) +/- SE

20 15 10 5

15.081-608-519 11.081-607-040

Whole aorta Apabetalone Placebo

16.040-776-379 8.092-895-111

Aortic sinus Whole aorta

PlaceboApabetalone (150 mg/kg)

 of -31% (p<0.016)

Aortic sinus

Jahagirdar Atherosclerosis 2015

slide-29
SLIDE 29

29

PNAS, 2013 110 (49):19754-9.

(+)- JQ1

(+)- JQ1 (+)- JQ1

Tandem BET bromodomains allows for inhibitor selectivity: Distinct expression effects: Apabetalone (selective) vs. JQ-1 (pan) BET inhibition

slide-30
SLIDE 30

PPARg PTN Adipo DAY 2 Pre-Adipo Enhancers Ranked By BRD4 Signal PPARg PTN

PTN

PPARg CEBPa

 BRD4: Log D2 vs D0 BRD4 Regulates the Adipogenic Program

DAY 0 PNAS, 2018

slide-31
SLIDE 31

BET Action BET Inhibition Pathologic Transcriptional Programs

slide-32
SLIDE 32

Hepatocytes Tubular cells

Renal:

ECs VSMCs MF T cells Adipocytes b Cells Cardiomyocytes

Cardiovascular: Inflammation: Metabolism:

Pltlets

BET Action Pathologic Transcriptional Programs BET Inhibition

Apabetalone

Atherosclerosis Injury Inflammation

Direct Indirect Indirect