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Mechanisms for Improved Insulin Sensitivity byBranched-chain Amino Acids Deprivation
Reporter : Fei Xiao, PhDReporter : Fei Xiao, PhD
Shanghai Institute for Nutritional Sciences, Chinese Academia of Sciences
Prevalence of diabetes
Background
Insulin signaling
Nature. 2001, 414:799-806
Insulin Receptor,
IR
Insulin Receptor
Substrate, IRS
AKT
Insulin resistance:
a physiological condition where insulin becomes less effective at lowering blood glucose
a common feature of many metabolic diseases
Background
The DPP Research Group, NEJM,2002
Background
Various strategies to treat insulin resistance
Background
Branched-chain amino acids (BCAAs)
L-leucine L-isoleucine L-valine
The role of leucine in insulin sensitivity
Increased serum leucine level:
* Improves the whole body glucose metabolism
* Does not alter susceptibility to diet-Induced obesity
J. Nutr. 139: 715–719, 2009.
* Increases insulin resistance in models of obesity
Cell Metab 9:311-326, 2009
Diabetes 54:2674-2684, 2005
Diabetes 56:1647-1654, 2007
?
Metabolic diseases(insulin sensitivity/glucose
metabolism)
Nutrient(BCAAs)
Genetic factors
sensing
Metabolism regulationX
Research interest of our work
Outline
Part The role of leucine deprivation in insulin sensitivityⅠ
Part Effects of individual BCAAs on insulin sensitivity Ⅱ and glucose metabolism in mice
Part Looking for new genes regulating insulin Ⅲ sensitivity by leucine deprivation model
The role of leucine deprivation in insulin sensitivity
Part Ⅰ
Leucine deprivation
Fat mass Lipolysis in WAT
UCP1 in BAT
CNS food intake
Serum Insulin Blood Glucose Normal
In Our Lab
Cell Metab 5:103-114, 2007 Diabetes 59:17-25
?
Part Ⅰ
HypothesisHypothesis
Leucine deprivation may improve insulin sensitivity
Part Ⅰ
Experimental DesignExperimental Design
control
85% control
(-)leu
control
0d
Collect tissuesChange different dietsMice were acclimated to control diet for 7 days
ControlControl (-)leu(-)leu Pair-fedPair-fed
7d 14d
Part Ⅰ
Blo
od
Glu
co
se
(m
g/d
l)Result 1: (-) leu improves insulin sensitivity in vivo
0
50
100
150
200
#*
Se
rum
Ins
ulin
(n
g/m
l)
0
0.2
0.4
0.6
#*
ctrl (-) leu pf
HO
MA
-IR
0.5
1
1.5
0
#*
Fasting Fasting
*: p<0.05 vs. control #: p<0.05 vs. pf
Part Ⅰ
Result 2: (-) leu improves insulin sensitivity in vivo
0 20 40 60 80 100120
Time (min)
ITT
Blo
od
Glu
cose
(m
g/d
l)
Time (min)
0
100
200
0 20 40 60 80 100120
400
500
300
0
50
100
150
200
Blo
od
Glu
cose
(m
g/d
l)GTT
**
#
# **
ctrl (-) leu pf
*#
##
**
*#
*: p<0.05 vs. control #: p<0.05 vs. pf
Part Ⅰ
Result 3: (-) leu improves insulin sensitivity in vivo
- + - +
p-IR
t-IR
p-AKT
t-AKT
ctrlIns
Liver WAT Muscle
Arb
itra
ry U
nit
s * *
100
200
00
p-IR p-AKT
100
200
p-IR p-AKT p-IR p-AKT
300
0
100
300
ctrl + Ins (-) leu + Ins
*
*200
* *
(-) leu
- + - +
ctrl (-) leu
- + - +
ctrl (-) leu
*: p<0.05 vs. control
Part Ⅰ
Results 4 :(-) leu improves insulin sensitivity under insulin-resistance conditions
C
HFD(-) leu HFD
Blo
od
Glu
cose
(m
g/d
l)
0
50
100
200
250
150
Time (min)B
loo
d G
luco
se (
mg
/dl)
0
200
400
600
0Time (min)
ctrl db/db (-) leu db/db
ctrl WT
40 80 12020 60 100
ITT
* *
**
# # #
ITT
0 40 80 12020 60 100
*
**
*
ctrl
**
*
** *
*: p<0.05 vs. HFD#: p<0.05 vs. ctrl
*: p<0.05 vs. ctrl db/db#: p<0.05 vs. ctrl WT
* *
Part Ⅰ
Summary 1
leucine deprivation improves insulin sensitivity under normal and insulin-resistant conditon
Mechanisms ?
Part Ⅰ
Nature 431:200-205, 2004
Role of mTOR/S6K1 signaling in insulin sensitivity
mTOR : mammalian target of rapamycin S6K1 : ribosomal protein S6 kinase 1
Part Ⅰ
Results 5 :(-) leu increases insulin sensitivity by decreasing mTOR/S6K1 signaling in vivo
Liver
p-S6K1
t-S6K1
p-S6
t-S6
p-mTOR
t-mTOR
ctrl (-) leu
0
50
100
150
200
Blo
od
Glu
cose
(m
g/d
l)
0 40 80 120
Time (min)
ITT
20 60 100
+ Ad-CA-S6K1
**
*
- Ad-CA-S6K1
*: p<0.05 vs. control
On a leucine-deficient dietA B
Part Ⅰ
GCN2
General control nonderepressible (GCN)2
A serine protein kinase
Function as a sensor for amino acid deprivation
●
●
●
Leucine deprivation
p-IR/p-IRS/p-AKT
p-mTOR /p-S6K1 GCN2
?
Part Ⅰ
Results 6:(-) leu increases insulin sensitivity by activation of GCN2
p-GCN2
t-GCN2
Liver
Arb
itra
ry U
nit
s
0
100
200 *
ctrl (-) leu
0 40 80 120
Time (min)
20 60 1000
50
100
150
Blo
od
Glu
cose
(m
g/d
l) Gcn2-/-
ITT
Gcn2+/+
* **
*: p<0.05 vs. control
Part Ⅰ
AMPK
AMP-activated protein kinase
Energy sensor
●
●
Target of many drugs●
Leucine deprivation
p-IR/p-IRS/p-AKT
p-mTOR /p-S6K1
GCN2
AMPK
?
Part Ⅰ
Results 7 :(-)leu improves insulin sensitivity via activation of AMPK
DN-AMPKIns
p-ACC
- -- + - +
+ +
p-IR
t-AMPK
t-IR
t-ACC
t-IRS1
p-IRS1(Tyr612)
HepG2
p-AKT
t-AKT0
+ DN-AMPK + Ins
100
Arb
itra
ry U
nit
s
50
150
**
*
p-IR p-IRS1 p-Akt
HepG2
+leu -leu
*
p-AMPK
t-AMPK
Liver
Arb
itra
ry U
nit
s
0
100
200
*
ctrl (-) leu - DN-AMPK + Ins
*: p<0.05 vs. control
Part Ⅰ
Summary2
Leucine deprivation increases hepatic insulin sensitivity via GCN2/mTOR/S6K1 and AMPK pathways
model
Leucine deprivation
p-IR/p-IRS/p-AKT
p-mTOR/p-S6K1
p-GCN2 p-AMPK
Part Ⅰ
Conclusion One
Elucidate the mechanisms underlying increased insulin sensitivity by leucine deprivation
GCN2/mTOR/S6K1 and AMPK pathways
Demonstrate a novel function for GCN2 in the regulation of insulin sensitivity
●
●
Part Ⅰ
The paper titled “leucine deprivation increases hepatic insulin sensitivity via GCN2/mTOR/S6K1And AMPK pathways” was published in Diabetes, 60:746-756,2011.
L-isoleucine (ile)
L-valine (val)
How about the other two branched-chain amino acids ?
Effects of individual branched-chain amino acids on insulin sensitivity and glucose metabolism in mice
Part Ⅱ
Results 8: (-)val and (-)ile improves insulin sensitivity in vivo
200
150
100
50
Time (min)
0Blo
od
Glu
cose
(m
g/d
l)
0 40 80 120
ITT
**
* *
A Bctrl (-) val ctrl (-) ile
Blo
od
Glu
cose
(m
g/d
l)
Time (min)
0
100
200
0 40 80 120
400
500
300
GTT
*
***
0
100
200
400
500
300
Blo
od
Glu
cose
(m
g/d
l)
Time (min)
0 40 80 120
GTT
*
***
0
50
100
150
200
Blo
od
Glu
cose
(m
g/d
l)
Time (min)
0 40 80 120
****
ITT
*
*
Part Ⅱ
Result 9: (-)val and (-)ile decrease mTOR/S6K1 and increase AMPK signaling
Liverctrl (-) Val
p-S6K1
t-S6K1
p-S6
t-S6
p-mTOR
t-mTOR
200
100
0
Liverctrl (-) Ile
p-S6K1
t-S6K1
p-S6
t-S6
p-mTOR
t-mTOR
Arb
itra
ry U
nit
s
Arb
itra
ry U
nit
s
* ** * * *
200
100
0
p-AMPK
t-AMPK
p-AMPK
t-AMPK
*
p-s6k
1
p-mTOR
p-s6
p-AM
PK
*
p-s6k
1
p-mTOR
p-s6
p-AM
PK
Part Ⅱ
150
100
50
0
* *
Blo
od
Glu
cose
(m
g/d
l)
0.4
0.2
0Ser
um
Insu
lin (
ng
/ml)
* *0.5
1
HO
MA
-IR
0
* *
ctrl (-) val (-) ile
Fasting Fasting
Results 10: Effects of individual BCAA deficiency on glucose metabolism
*: p<0.05 vs. control
Part Ⅱ
200
150
100
50
0
* *
Blo
od
Glu
cose
(m
g/d
l) 1.5
1
0.5
Ser
um
Insu
lin (
ng
/ml)
0
* *
g6pase0
100
200
Rel
ativ
e m
RN
A (
%)
Fed Fed
pepck
**
**
Results 11: Effects of individual BCAA deficiency on glucose metabolism
ctrl (-) val (-) ile( - ) leu
*: p<0.05 vs. control
Part Ⅱ
Results 12: BCAA deprivation for 1 day improves whole body insulin sensitivity
200
Blo
od
Glu
cose
(m
g/d
l)
100
0
** *
*
200B
loo
d G
luco
se (
mg
/dl)
100
0
*
** *
200
Blo
od
Glu
cose
(m
g/d
l)
100
0
*
**
*
Time (min)0 40 80 120
Time (min)0 40 80 120
Time (min)0 40 80 120
(-) leu (-) val (-) ile
ctrl (-) BCAA
*: p<0.05 vs. control
Part Ⅱ
Conclusion Two
Leucine deprivation represents a general effect of BCAAs on regulation of insulin sensitivity
●
● The effect of BCAAs deprivation differs in glucose metabolism
Part Ⅱ
The paper titled “Effects of individual branched-chain amino acids deprivation on insulin sensitivity and glucose metabolism in mice ” was published in Metabolism, 2014.
Looking for new genes regulating insulin sensitivity by leucine deprivation model (gene chip)
Part Ⅲ
Hepatic Gene Chip of lecine-deprived male mice
0200400
600
800
Prl
R m
RN
A le
vel
*
liver
con (-) leu
(( --)) leu/conleu/con Gene Gene numbernumber
Upregulate more than Upregulate more than twice twice
984984
Downregulate more than Downregulate more than twicetwice
11631163
Prolactin receptor (PRLR)
Part Ⅲ
Prolactin Receptor (PRLR)
Prolactin : A hormone best known for its role in lactation.
PRLR: Present in nearly all organs and tissues. Numerous biological functions of PRLR have been identified. (Regulates glucose levels by modulating the secretion of insulin)
a direct effect on insulin sensitivity
?
Part Ⅲ
working model
PRLR
p-STAT5
p-IR / p-AKT
db/db
Insulin sensitivity
Normal condition
Insulin resistance Insulin sensitivity
Leucine deprivation
GCN2/ mTOR/S6K
Part Ⅲ
Conclusion ThreeIdentify a novel function for hepatic PRLR in the regulation of insulin sensitivity
Provide important insights in the nutritional regulation of PRLR expression
●
●
Part Ⅲ
The paper titled “PRLR Regulates Hepatic Insulin Sensitivity in Mice via STAT5” was published in Diabetes, 62:3103-3113,2013.
Our lab:Feifan Guo, Ph.DChunxia Wang, Ph.DJunjie Yu , Ph.DShanghai ChenKai LiHao LiuYajie GuoJiali DengYuzhong XiaoYalan Deng
Acknowledgments
Previous members: Ying Cheng, PhDQian Zhang, Ph.DYing Du , Ph.DTingting Xia, Ph.DQingshu MengZhiying HuangBin Liu
Douglas cavener (Penn State Univ) Brad lowell (Harvard Med School)Xiang Gao (Nanjing Univ)Yong Liu (INS, CAS) Hongguang Sheng (CAS clinical center)
Houkai Li, PhD Ziquan Li, Ph.D