Luca Valenti Department of Pathophysiology and Transplantation, Università degli Studi di Milano Internal Medicine, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico [email protected] Genetics & Epigenetics Monotematica AISF 8 Ottobre 2015
Luca ValentiDepartment of Pathophysiology and Transplantation, Università degli Studi di Milano
Internal Medicine, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico
Genetics & Epigenetics
Monotematica AISF 8 Ottobre 2015
Steatosis
Peri-cellular/venular fibrosis Cirrhosis
Histological spectrum of NAFLD:From simple steatosis to NASH and HCC
HCC
Lobular inflammationBallooning
Liver histology in 351 consecutive severely obese individuals
Normal liver 14%
Simple steatosis 31.5%
NASH w/o Significant fibrosis
31%
NASH & Significant fibrosis
11.5%
Browning, Hepatology 2004
Prevalence of steatosis varies with ethnicity
Hispanics Whites Blacks
Fat
ty li
ver
%
45%
M F
24%
M F
42%
M F
24%
LYPAL1
Speliotes
PPP1R3B
GCKR
NCAN
TRIB1
Chambers
HSD17B13
CPN1
GWA studies in NAFLD: an overview
PNPLA3rs738409
C>G
Romeo
Anstee
Kitamoto
1 48117910
I148MDGGVGASAG
16647
PATATIN-LIKE PHOSPHOLIPASE DOMAIN-CONTAINING 3 (PNPLA3)
II
IM
MM
0
2
4
6
Hep
atic
Fat
(%
)
p = 7 x 10-14
0
10
20
30
40
BM
I (kg
/m2 )
0
1
2
3
4
HO
MA
-IR
0
25
50
75
100
Pla
sma
TG
(m
g/d
l)PNPLA3 rs738409 C>G (I148M)
always confirmed top hit with larger effect size
Tg
Endoplasmic Reticulum
Lipid droplets
Obesity and insulin resistance favor lipid droplets accumulation in hepatocytes
FFAs
Extracellularspace
VLDLsecretion
Early Golgi
TM6SF2167E Nascent
VLDL
ObesityInsulin resistance
PNPLA3148I
HFC: 0-5%
Dongiovanni, BMC Research International, 2015
Endoplasmic Reticulum
Lipid droplets
Romeo, Nat Genet 2008, He, J Biol Chem 2010; Ruhanen, J Lipid Res 2014; Dongiovanni, World J Gastroentorol2013; Dongiovanni, Hepatology 2014
Impaired lipid droplets remodeling causes NASH in PNPLA3 I148M carriers
FFAs
Extracellularspace
VLDLsecretion
Early Golgi
TM6SF2167E Nascent
VLDL
PNPLA3148M
ObesityInsulin resistance
Tg
HFC: 6% �
Alle
licO
dd
s R
atio
0
0,5
1
1,5
2
2,51.77
[1.42-2.19]p= 2.8 x 10-7
1.55[1.03-2.34]
p= 3.5 x 10-2
2.20[1.80-2.67]
p=4.7 x 10-15
945 1,374n= 2,503
Trépo E, Hepatology 2014
PNPLA3 I148M and HCC risk in cirrhosisan individual patient data meta-analysis
Obesity andinsulin resistance
Excess alcoholFructose
Hepatitis C virus
PNPLA3 148I
Mild uncomplicated steatosis
PNPLA3 148M
Steatohepatitis &
fibrogenesis
Cirrhosis
Valenti, Hepatology 2012Valenti, Dig Liver Dis 2013
PNPLA3 I148M and progressive liver disease:a new paradigm in hepatology
Hepatocellularcarcinoma
PNPLA3 148M/M
Directcarcinogenic
activity
Endoplasmic Reticulum
Lipid droplets
Kozlitina, Nat Genet 2014; Holmen, Nat Genet 2014; Mahdessian, PNAS 2014; Dongiovanni, Hepatology 2014
Impaired VLDL secretion in E167K TM6SF2carriers causes NASH
FFAs
Extracellularspace
VLDLsecretion
Early Golgi
TM6SF2167K Nascent
VLDL
ObesityInsulin resistance
PNPLA3148I
HFC: 6% �
E167K TM6SF2
0
20
40
60
80
100
NASH Advanced fibrosis Carotid plaques
Pre
vale
nce
%
EE
EK + KK‡
p=0.003 p=0.008 p=0.031
n = 1,044
n = 157
TM6SF2 E167K variant disentangles NASH from cardiovascular disease
Endoplasmic Reticulum
Fattyacids
Extracellularspace
VLDLsecretion
Early Golgi
TM6SF2Nascent
VLDL
PNPLA3
ObesityInsulin resistance
APOB
Lipid droplets
GCKR
HyperglycemiaHyperinsulinemia
TRIB1
MTTP
Mitochondria
Lipotoxicity FFAR4IL28B
UCP2SOD2
IRS1ENPP1
KLF1FABP5
LYPLAL1
Maternal fat intake alters gene expression and DNA methylation
Dudley, PONE 2011
p21 demethylation correlates with:• increased expression
• cell senescence
Differential methylation in NAFLD impacts on gene expression and disease
severity
Murphy, Gastroenterology 2013
Key points :� NASH is a strongly heritable disease
� PNPLA3 I148M variant is the major common genetic riskfactor, but the phenotypic expression triggered byenvironment and diet (obesity, fructose, alcohol)
� Most genetic risk variants regulate hepatic lipidmetabolism
� NASH is associated with altered chromatin remodeling,mainly characterized by DNA hypomethylation, andaltered miRNA expression
� Epigenetic modifications mediate the effect ofenvironment, diet-insulin resistance, aging andheritability on NAFLD phenotype
AcknowledgementsMetabolic Liver Diseases Lab
Benedetta DonatiMarta MilanoMarica MeroniOscar BorsaniGuido BaselliClaudia Lanti
Paola DongiovanniRaffaela RamettaAlessandro Pietrelli
Clinical centerSilvia FargionAnna FracanzaniCristina BertelliErika FattaGiuseppina PisanoSerena PelusiMarianna PorzioRosa LombardiVittorio Borroni
UdineGiorgio Soardo
Migliavacca CenterMassimo Colombo
Alessio AghemoPietro Lampertico
INGMRaffaele Defrancesco
Cristina Cheroni
PathologyValentina VairaMarco MaggioniSilvano Bosari
NewcastleQuentin Anstee
Chris Day
GothenburgStefano Romeo
New YorkDomenico Accili
Utpal Pajvani
SurgeryStefano GattiEnrico Mozzi
TorinoElisabetta Bugianesi
Ester VanniRoma
Valerio NobiliLuca Miele, Anna Alisi
PalermoSalvo Petta
Zurich/DresdenFelix Stickel
Jochen Hampe
DallasJulia Kozlitina