Post on 25-Jul-2018
transcript
The Renin-angiotensin System in Obesity and Vascular Diseases
Lisa A. Cassis, PhD
Professor and Chair
Department of Molecular and Biomedical Pharmacology
University of Kentucky
No relevant financial relationships exist.
Harriett Dustan
• Pioneer in clinical cardiovascular research
• 1st person to give sodium nitroprusside to humans,
• Thiazide diuretics potentiate blood pressure lowering of other antihypertensives,
• Definition of hemodynamics of primary aldosteronism,
• Pathophysiology of obesity-related hypertension
In Memoriam, Circulation 100:2122-2123, 1999
Acknowledgments: Lab/Trainees
The Ever Evolving RAS Angiotensinogen
Angiotensin I (1-10)
Renin
Angiotensin II (1-8)
ACE
Angiotensin III (2-8)
Aminopeptidase A
Angiotensin IV (3-8)
Aminopeptidase N
Ang1-9 Ang1-7 ACE2 ACE
Prorenin ?
(Pro)Renin Receptor
Activates Renin
Signals
Research Program
Angiotensin II
Adipose Tissue Atherosclerosis
AAA Hypertension
EC
Muscle
Adventitia
Adipose
Ao
Ao
Ao
Ao
Ao
Ao
Ao
Ao
Ao Ao Ao
Ao
Ao
Ao
Ao
Expression of RAS components during adipocyte differentiation
Undiff4hrs 8hrs 12hrs D1 D2 D3 D4 D5 D6 D7 D8 D9 D100.0
0.5
1.0
1.5
2.0
*
*
*
*
**
* *
*,P<0.05
AO
/18S
Undiff 4hrs 8hrs 12hrs 1d 2d 3d 4d 5d 6d 7d 8d 9d 10d0.00
0.01
0.02
0.03
0.04
**
AT
1a/1
8S
*
*,P<0.05
Angiotensinogen
AT1 receptor
ACE2
UD 4hrs8hrs12hrs D1 D2 D3 D4 D5 D6 D7 D8 D9 D100.000
0.025
0.050
0.075
0.100
***
*
*,P<0.05
AC
E2/1
8s
Undifferentiated 1 2 3 4 5 6 7 8 9 10
Cocktail
Gupte et al., AJP 295: R781-8, 2008
Prevalence Obesity* Trends Among U.S. Adults
(*BMI 30)
No data <10% 10-14% 15-19% 20-24% 25-29% >30%
Source: CDC, Behavioral Risk Factor Surveillance System, February 2010
1999 1990 2009
OBESITY
↑Angiotensin II
Hypertension
↑Angiotensinogen (AGT)
Frederique Yiannikouris, PhD
Neocassette Exon 2
Lox P Lox P FRT FRT
Lox P Lox P
Exon 3
Flp
Ap2-Cre
Lox P flanked allele
Deleted allele
Lox P
FRT
Exon 2 Exon 3 Neo
Lox P
Exon 3
a
b
c
0
10
20
30
40
Day 0 Day 8
Agtfl/fl
AgtaP2
*
*,**
**A
GT
(n
g/m
l)
AGT mRNA abundance AGT protein
Agtfl/fl, wild type, AgtaP2 adipocyte AGT deficient
Adipocyte AGT deficiency has no effect on body weight, fat mass, or glucose tolerance
A
0
10
20
30
40
50
LF HF
** *,**
*
AgtaP2
Agtfl/fl
Fat
mass (
% l
ean
)
0
10
20
30
40
50
60
70
80
LF HF
** **
Agtfl /fl
AgtaP2
Lean
mass (
% B
W)
B
0 2 4 6 8 10 12 14 160
Agtfl/fl, LF
AgtaP2, LF
Agtfl/fl, HFAgtaP2, HF
*****
* ***
***
20
30
40
50
Time
Bo
dy w
eig
ht
(g)
Agtfl/fl = controls AgtaP2 = Adipocyte AGT deficient
Adipocyte deficiency of AGT ablates obesity-hypertension
0
LF HF
Agtfl/fl
AgtaP2 *
**
100
110
120
130
140
SB
P (
mm
Hg
)
Hypertension, in press, 2012
Reductions in plasma AngII in obese adipocyte AGT-deficient mice are paralleled by reduced adipose AngII content
0
50
100
150
200
250
300
Agtfl/fl
AgtaP2
LF HF
*
**
An
g II (p
g/m
l)
0
5000
10000
15000
20000
25000
Agtfl/fl
AgtaP2
LF HF
An
gII (
pg
x t
ota
l fa
t
ma
ss
)
PLASMA ADIPOSE TISSUE
Summary
• Deficiency of AGT in adipocytes prevents obesity-induced increases in plasma AngII and obesity-related hypertension
• Tissue production of AngII (e.g., adipose) can be a significant source of circulating AngII in the setting of obesity and in the development of obesity-induced hypertension
Hypertension, in press, 2012
OBESITY
↑Angiotensin II (AGT)
Undiff 4hrs 8hrs 12hrs 1d 2d 3d 4d 5d 6d 7d 8d 9d 10d0.00
0.01
0.02
0.03
0.04
**
AT
1a/1
8S
*
*,P<0.05
Why do adipocytes have AT1aR? What does AngII do to an adipocyte? Is this influenced by obesity and does it contribute to obesity-associated diseases?
Kelly Putnam
Endocrinology, epub ahead of press, 2012
Adipocyte AT1aR
Liver Kidney Heart Brain Spleen BAT WAT0.0
0.1
0.2
AT1aRfl/fl
AT1aRaP2
*
* *
0.2
1.2
AT
1a
R:1
8s
X FLPE
LoxP3
FRT
LoxP1
Exon 3 AT1aRfl/fl
Exon 3 Neocassette
FRT FRT
LoxP1 LoxP2 LoxP3
X aP2-Cre
AT1aRaP2
Floxed AT1aR Gene
LoxP1-3
Adipocyte deletion of the AT1aR
Adipocyte AT1aR deficiency has no effect on the development of obesity
0 5 10 15
20
40
60
AT1aRaP2 HF
AT1aRfl/fl HF
AT1aRaP2 LF
AT1aRfl/fl LF
Weeks on diet
We
igh
t (g
)
0 AT1aRfl/fl
AT1aRaP2
AT1aRfl/fl
AT1aRaP2
0
20
40
60
80
100
% Lean mass
% Fat mass
LF HF
* *
% o
f b
od
y m
as
s
, but……
0
1000
2000
3000
4000
5000
6000
7000
0
20
40
60
80AT1aR
fl /fl LF
AT1aRaP2
LF
Adipocyte size (m2)
# o
f c
ell
s
LF HF0
1000
2000
3000
4000AT1aR
fl /fl
AT1aRaP2
***
Me
an
ad
ipo
cyte
siz
e (
m2)
AT1aRfl/fl
AT1aRaP2
0.0
0.2
0.4
0.6
0.8
1.0
*
Ab
so
rb
an
ce
(5
10
nm
)
AT1aRfl/fl
AT1aRaP2
0
200
400
600
*
PP
AR:1
8s
Summary
• Adipocytes have AT1aR, but they play no major role in the development of obesity
• In lean mice, deficiency of AT1aR on adipocytes decreases adipocyte differentiation, resulting in hypertrophy of remaining adipocytes
OBESITY
ACE2 AngII Ang-(1-7)
UD 4hrs8hrs12hrs D1 D2 D3 D4 D5 D6 D7 D8 D9 D100.000
0.025
0.050
0.075
0.100
***
*
*,P<0.05
AC
E2/1
8s
X
Sean Thatcher, PhD Assistant Professor
Manisha Gupte, PhD
Hypertension prevalence is greater in men than women before menopause: Are females protected
against obesity hypertension?
Age Men (%) Women (%)
20-34 9.2 2.2
35-44 21.1 12.6
45-54 36.2 36.2
55-64 50.2 54.4
65-74 64.1 70.8
75 and older 65.0 80.2
All 31.8 30.3
CDC
Menopause
0 5 10 150
515
20
25
30
35
40
45
50
55Male, LFMale, HF
Female, LF
Female, HF
*
**
**
**
* *
* *
**
**
*
Bo
dy w
eig
ht
(gm
)
Male Female0
5
10
15
20
25LF
HF *
*,**
**
Fat
mass (
g)
Female mice gain more weight and fat mass than males
65%
97%
86%
236%
*, P<0.05 compared to LF
*, P<0.05 compared to LF **, P<0.05 compared to male Male Female
0
50
100
150LF
HF **
**
SB
P N
igh
t (m
mH
g)
but are protected from obesity-hypertension
Arteriosclerosis, Thrombosis and Vascular Biology 32:1392-9, 2012
The AngII/Ang-(1-7) balance is different between obese males and females, and ACE2 deficiency promotes
hypertension in both sexes
Male Female0.0
0.2
0.4
0.6
0.8 LF
HF
***
**
Pla
sm
a A
ng
-(1-7
) (n
g/m
l)
Male Female0
50
100
150
200Ace2
+/+, HF
Ace2-/-
, HF
*,****
*
SB
P N
igh
t (m
mH
g)
Summary
• ACE2 is important in regulating the AngII/Ang-(1-7) balance in the development of obesity-hypertension
• Females rule!, they are protected against obesity-hypertension potentially through an ACE2-dependent mechanism
Research Program
Angiotensin II
Adipose Tissue Atherosclerosis
AAA Hypertension
AAA
• 13th leading cause of death in the United States
• Risk factors – Male Gender
– Smoking
– Age >65
– Family history
– Hypertension
– Obesity
• No pharmacologic treatments for AAA • Surgical repair is the only therapeutic option to prevent
rupture (> ~ 5.0 cm)
Allison et al. J Vasc Surg 2008; 48:121-7, Golledge et al. Circulation 2007; 116:2275-2279.
Angiotensin II
28 days Osmotic mini-pump
apoE-/- LDLr-/-
AAA
Atherosclerosis
AngII-induced Vascular Pathology
Daugherty A, Manning MW, Cassis LA. J Clin Invest. 2000 Jun;105(11):1605-12.
Risk Factors: Effects of Male Gender
Hypothesis:
Sex hormones mediate gender differences in AngII-induced vascular diseases by regulating the AT1a receptor
Xuan Zhang, PhD
Androgen is the primary regulator of AAA susceptibility in male mice through regulation of
aortic AT1aR
Sham Orx
% A
AA
Incid
ence
0
20
40
60
80
100
*
Male Female
% In
cid
ence
0
20
40
60
80
100
intact 1 week 5 weeks 1 week 5 week0.0
0.1
0.2
0.3
0.4
0.5
0.6
thoracic
abdominal
Castration Castration+DHT
AT
1a/1
8S
Male/Female AAA susceptibility Testosterone is the mediator
Aortic Development
Adapted from Majesky M. ATVB 2007
AR
Can we turn a female into a male with enhanced
AAA susceptibility by exposing her to testosterone
early in life?
Day 1
Testosterone (400 µg/mouse)
or Vehicle
10-12 weeks
•Aortic gene expression
•AngII infusion
Question
Circulation Research 25:373-85, 2012.
Neonatal testosterone strikingly promotes AngII-induced AAAs in adult female mice
500 750 10000
20
40
60
80vehicletestosterone
AngII infusion rate (ng/kg/min)
AA
A in
cid
en
ce
(%
)
*,**
A
C
B
vehicle testosterone
saline AngII0.0
0.5
1.0
1.5
2.0
2.5vehicletestosterone
Maxim
al exte
rnal
ab
do
min
al ao
rtic
dia
mete
r (m
m)
*,**
*
vehicle testosterone0.00
0.01
0.02
0.03
0.04
0.05thoracic
abdominalA
T1aR
/18s r
ati
o
ApoE-/-
*,**
Summary
• Testosterone has pronounced effects during development to influence the vasculature.
• AT1a receptors are a target of testosterone in smooth muscle cells to influence vascular remodeling in aneurysm formation.
• Vascular disease is sexually dimorphic.
Acknowledgments: Grant Support
• NIH HL73085 (LAC)
• NIH HL107326 (LAC)
• NIH P01 HL080100 (AD, LAC)
• NIH P42 ES007380 (BH, LAC)
• NIH T32 DK007778 (LAC)
• NIH P20 GM103527 (LAC)
• AHA: 0815419D (MG), 11PRE6760002 (KP), Pre0815513D (XZ), 12PRE12050430 (RS)
Alan Daugherty