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Bernard Bouscarel, Ph.D., D.Sc. Associate Professor of Biochemistry and Molecular Biology and of Medicine Director, Digestive Diseases Center Director, Molecular Medicine Program [email protected] 202-994-2114. 1988. Bile acids, hormone AA responses and cirrhosis/diabetes. - PowerPoint PPT Presentation
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Bernard Bouscarel, Ph.D., D.Sc.
Associate Professor of Biochemistry and Molecular Biology
and of Medicine Director, Digestive Diseases Center
Director, Molecular Medicine Program
[email protected] 202-994-2114
Cell signaling and bile acid metabolism1988
1992
Chemotherapy and TopoI inhibitor
1994
UDCA as a chemotherapeutic
agent2000
Bile acid and chemoprevention
2006
UDCA and cholestatic liver
diseases
Elucidation of hepatic hormonal and AA response
Bile acids and skin fibroblast signaling
Bile acids and fibroblast proliferation
Bile acids and hepatic cell
proliferation
Bile acids, hormone AA responses and cirrhosis/diabetes
Relationship between fibroblasts and HSC
Hepatic fibrosis prevention
Bile acids & Taurine transport
Bile acids and hepatic signaling
C M C M
Total PKC
P-PKC
-actin
CTL CDCA
(1)
(1)
(2.13)
(4.45)
PKC phosphorylation
glucagon
Bile Acid
DAG PIP2IP3
Ca2+
? P
P P
?
??
GR
P ?
?P
PSDAG
Ca2+
PKC
Catalytic domain
Pseudosubstrate
PLC
GS
AC
ATP
cAMP
Cholestasis: Bile acids/ hormonal response
Background:
Hypothesis:
Methods:PKCtranslocation
10’
6’
0’
Co-localization of GR & PKC
0’ 20’
Green: GR, Red: PKC, Yellow; merge
GR phosphorylation
CTL CDCA(25M)
PL
WB
(1) (3.0)
Bile acids are responsible for the decreased hepatic glucagon responsiveness in cholestasis through a mechanism involving PKC and GR phosphorylation.
Genomics, proteomics, and pharmacologic approaches to identify the relevant amino acids phosphorylated by bile acids leading to activation of PKC and inhibition of GR cellular response.
Le et al. Am J Physiol. 2006Ikegami et al. Endocrinology. 2006Krilov et al. (in preparation)
GR: glucagon receptorAC: adenylyl cyclasePLC: phospholipase C
Cholestatic and cirrhotic patients (50-80%) display: glucose intolerance decreased gluconeogenic response to glucagon hepatic resistance to glucagon attenuation of glucagon-induced cAMP production
Bile acids attenuate glucagon-induced cAMP production through a mechanism involving PKC
Fibrosis: Bile acids/ fibroproliferation
Background:
Hypothesis:
Methods:
Co-Inv. and Collaborators:Drs. Rojkind, Ceryak and Kashanchi
Drs. Lin, Latham and Piper
Chronic liver disease and cirrhosis in particular, is the 12th leading cause of death in US.
Fibrosis is a hallmark of cirrhosis
Hepatic stellate cells (HSC) are key in the development of liver fibrosis.
ILK
Cox2
Growth arrest/death
Proliferation survival
Normal HSC
Cox2
ILK
Fibrotic HSC
Growth arrest/death Proliferation
survival
Zhang et al. Hepatology. 2006Meng et al. Am J Physiol. 2006Meng & Bouscarel (submitted)
HSC
CTL Chol
ILKCox-2
CDCACTL
Normal
CirrhosisFXR= farnesoid X receptorPKC= protein kinase CP38= p38 MAPKILK= integlin-liked kinase
PI3K
AKT
PKCFXR
ILKCox2P38
Proliferation
Bile acids
BA stimulate COX-2-mediated cell cycle arrest/death. In fibrosis, this signal is blunted through increased ILK expression/ activation fibroproliferation.
Isolation of HSC and Human skin fibroblasts (HSF) from control and patients with acute/chronic cholestasis.
Pharmacologic, genomic, and proteomic methods to identify key determinants of fibroproliferation.
Liver
Cancer: Bile acids/ topoisomerase I inhibitors
Background:
Purpose/ Methods:
Compare the effect of various agents, BA, H+-pump inhibitor, PLC, CPT-11 analogs, CPT-11…. on:
•Tumor cell metastasis•Survival rate•Cell proliferation, apoptosis, cell cycle factors•Tumor gene expression
Colorectal cancer (CRC) is a leading cause of cancer-related death.
Bile acids play an important role in the etiology of CRC.
Certain bile acids (UDCA) may have chemotherapeutic properties against CRC.
CPT-11 (Irinotecan, Camptostar) is one of the leading anti-cancer drugs for CRC therapy.
Liver
Spleen
Kidney
Heart
LungSpleenFluorescence intensity
Liver
2 weeks later
I.P. injection
CPT-11
UDCA
drinking
MC-26 cells transfected with GFP
Spleen
Liver
BALB/c mice
Spleen
Liver
BALB/c mice
Ikegami et al. Cancer Res. 2002Ikegami et al. Mol Cancer Ther. 2006Ikegami et al. (submitted)
Hypothesis:
UDCA enhances the antitumor chemotherapeutic
action of CPT-11.
www.gwu.edu/~ddc/
Bernard Bouscarel, PI
Jiamping Meng, Senior Scientist
Teruo Miyazaki, Post Doc
Maryam Alrashid, 5th year IBS student
Lada Krilov, 4th year IBS student
Amy Nguyen, 2nd year IBS student
Helen Johnston, 1st year IBS student (Rotation)
Nara Lee, Undergraduate student
Ivy Akid, Undergraduate student