studies

HEPATOLOGY, VOLUME 62, NUMBER 1 (SUPPL) AASLD ABSTRACTS 301A
Here, we investigated the underlying mechanisms of immune
tolerance by the gut-liver axis, focusing on interactions between
gut microbiota and hepatic immune competent cells. METHODS:
Male C57BL/6 mice were administered an initial and subsequent
sub-lethal dose of ConA to induce immunological tolerance.
Liver mononuclear cells were separated 12 h after the
final ConA injection and analyzed by flow cytometry. Immune
cell subset cytokine production stimulated with TLR ligands was
measured and the composition of intestinal bacterial flora was
evaluated by T-RFLP and comprehensive metagenomics. Intestinal
permeability was measured by FITC-dextran following
ConA injection. Mice were treated with antibiotics (ampicillin,
neomycin, metronidazole, and vancomycin) or fecal microbiota
transplantation to clarify the role of the gut-liver axis in liver
tolerance. RESULTS: A single ConA injection induced severe
liver inflammation but ConA administration 7 days after initial
injection increased immunosuppresive CD11c + DCs (D7-cDC)
and regulatory T cells in the liver and promoted immunological
tolerance. D7-cDC had regulatory characteristics and produced
IL-10 and TGF-β upon TLR9 ligand stimulation especially
from damaged hepatocytes. As an initiation of liver tolerance,
intestinal permeability was significantly increased at 4 h following
a single ConA injection. Importantly, the composition of
intestinal bacterial flora changed and the ratio of Clostridium
subcluster XIV to Bacteroides increased thereafter. Transplantation
of fecal microbiota derived from mice post-ConA administration,
but not from untreated mice, to gut sterilized mice
induced immunosuppressive CD11c + cDCs and regulatory T
cells in the liver and reduced liver injury by ConA. A similar
result was observed in germ-free and gnotobiotic mice inoculated
with fecal microbiota derived from ConA-injected SPF
mice. CONCLUSIONS: Dysbiosis with increased intestinal permeability
following ConA administration promotes the migration
of immunosuppressive cells in the liver in preparation for
further liver injury. This study identifies a novel homeostasis
pathway that regulates immune activation and tolerance in the
liver through the gut-liver axis.
Disclosures:
Takanori Kanai - Grant/Research Support: Mitsubishi Tanabe Pharma Corporation
The following authors have nothing to disclose: Nobuhiro Nakamoto, Hirotoshi
Ebinuma, Po-sung Chu, Nobuhito Taniki, Takeru Amiya, Akihiro Yamaguchi,
Shunsuke Shiba, Hidetsugu Saito
182
Chronic ethanol feeding suppresses Con A induced T cell
response and hepatitis in ALDH2-deficient mice
Yanhang Gao 1,2 , Yong He 1 , Dechun Feng 1 , Zhou Zhou 1 , Bin
Gao 1 ; 1 NIAAA, National Institutes of Health, Rockville, MD;
2 Hepatology, The first hospital of Jilin University, Changchun,
China
Background and Aims: Aldehyde dehydrogenase 2 (ALDH2)
is well known about its role on detoxifying aldehydes in ethanol
metabolism. An ALDH2 inactivating mutation is the most
common single point mutation in humans, mostly found in East
Asians, which can cause acetaldehyde accumulation after
alcohol consumption. However, how acetaldehyde accumulation
affects T cell response and hepatitis in ALDH2-deficent
individuals remains unknown. Methods: Wide-type and ALDH2
knockout mice were subjected to ethanol feeding for 6 weeks,
followed by injection of a single dose of Concanavalin A (Con
A). Liver injury and serum cytokine levels were evaluated.
Results: Con A injection rapidly induced T cell hepatitis, which
recapitulates the histological and pathological sequelae of T
cell-mediated hepatitis in viral hepatitis patients. Compared
with ethanol-fed wild-type mice, ethanol-fed ALDH2 -/- mice had
lower degree of liver damage post Con A injection, as demonstrated
by the lower level of serum alanine aminotransferase
(ALT), the less infiltration of neutrophils, the fewer number of
activated macrophages, and the smaller area of necrosis in
the liver. Furthermore, serum levels of several pro-inflammatory
cytokines including IFN-γ, TNF-α, MCP-1, IL-4, IL-6, IL-10,
IL12p70, were lower in ethanol-fed ALDH2 knockout mice than
in wide-type mice post Con A injection. In agree with serum
cytokine levels, hepatic activation of the IFN-, IL-6, IL-4 downstream
signaling molecule signal transducer and activator of
transcription (STAT1, 3, 6) were lower in ALDH2 knockout mice
than in wide-type mice. Furthermore, ethanol-fed ALDH2 knockout
mice had much higher levels of plasma corticosterone than
ethanol-fed wild-type mice. Inhibition of endogenous glucocorticoid
activity by pretreatment with the glucocorticoid receptor
antagonist RU-486 restored Con A-mediated liver injury in
ALDH2-deficeint mice. Conclusions: Chronic ethanol feeding
results in greater elevation of plasma corticosterone levels in
ALDH2 knockout mice than in wild-type mice. These elevated
corticosterone levels inhibit Con A-induced T cell response and
hepatitis in ALDH2 knockout mice. ALDH2-deficient individuals
who are excessive drinkers may have reduced T cell response
and are more susceptible to hepatitis viral infection.
Disclosures:
The following authors have nothing to disclose: Yanhang Gao, Yong He, Dechun
Feng, Zhou Zhou, Bin Gao
183
The antifibrotic effect of IL-4Rα signaling depends on
macrophage subsets prevalent during liver fibrosis progression
and reversal
Shih-Yen Weng 1 , Santosh Vijayan 1 , Xiaoyu Wang 1 , Yilang Tang 4 ,
Kornelius Padberg 1 , Yong Ook Kim 1 , Brombacher Frank 5 , Jeff R.
Crosby 3 , Michael L. McCaleb 3 , Ari Waisman 4 , Ernesto Bockamp 1 ,
Detlef Schuppan 1,2 ; 1 Institute of Translational Immunology, University
Medicine, Johannes Gutenberg University, Mainz, Germany,
Mainz, Germany; 2 Beth Israel Deaconess Medical Center, Boston,
MA; 3 Isis Pharmaceuticals, Carlsbad, CA; 4 Institute for Molecular
Medicine, Mainz, Germany; 5 Institute of Infectious Disease and
Molecular Medicine, Cape town, South Africa
Background and aims: In response to various stimuli, macrophages
can be functionally divided into M1 (inflammatory) and
M2 (anti-inflammatory) subsets. Alteration of the M1-M2 ratio
likely impacts liver fibrosis progression and reversal. IL-4Rα,
which is activated by IL-4 and IL-13 has been linked to M2
polarization. However, the functional role of IL-4Rα in liver
fibrosis progression and reversal remained unclear. Methods:
IL-4Rα -/- and wild type mice were treated with CCL 4
via oral
gavage for 6 weeks. Liver fibrosis reversal was investigated
after 2 weeks of CCL 4
withdrawal. Antisense oligonucleotides
(ASO) were applied intraperitoneally (40mg/kg, 3 times per
week) during the 6 week s of CCL 4
treatment or the during 2
weeks off CCL4. Results: At 6 weeks of CCL 4
treatment, IL-4Rα -/-
mice had 25% less fibrosis than their wild type littermates. Flow
cytometry analysis of the liver of IL-4Rα -/- mice showed less
inflammation indicated by a reduction of B cells, and CD4
and CD8 T cells. The proportion of resident M1 macrophages
was significantly increased and that of proinflammatory monocytic
Ly6c hi macrophages largely reduced in IL-4Rα -/- livers.
To further validate IL-4Rα function, mice with cell specific deletion
of IL-4Rα were generated and subjected to CCL 4
treatment.
No overt change of liver fibrosis induction was found
in T cell-specific knockout mice (IL-4Rα ∆CD4 ). However, after 6
weeks of CCL4-treatment, fibrosis was significantly attenuated
in mice with myeloid cell-specific IL-4Rα deletion (IL-4Rα ∆LysM ).