studies

HEPATOLOGY, VOLUME 62, NUMBER 1 (SUPPL) AASLD ABSTRACTS 655A
(iv) pro-fusion (Mfn2) and pro-fission (Fis1) proteins of mitochondria,
were all significantly increased in rPADs from INT-
767-treated compared to HFD rabbits. Transmission electron
microscopy demonstrated that INT-767 treatment normalized
HFD-induced reduction of mitochondrial cristae. INT-767 treatment
was also able to: (i) improve mitochondrial architecture
and dynamic, with the majority of mitochondria continuously
moving and changing shape, as assessed by time lapse imaging
with mitochondria-targeted fluorescent probe MitoTracker,
(ii) reduce superoxide production, assessed by measuring the
time-dependent accumulation of dihydroethidium-derived fluorescence,
(iii) improve insulin sensitivity assessed by measuring
3 H-2-deoxy-D-glucose uptake in response to increasing insulin
concentrations. In conclusion, the dual FXR/TGR5 agonist INT-
767 ameliorates the metabolic profile and reduces visceral
adiposity by improving insulin sensitivity and promoting brown
differentiation in visceral adipose tissue.
Disclosures:
Luciano Adorini - Employment: Intercept Pharmaceuticals
Mario Maggi - Consulting: BAYER, ELI LILLY, MENARINI, PROSTRAKAN, INTER-
CEPT
The following authors have nothing to disclose: Linda Vignozzi, Ilaria Cellai,
Sandra Filippi, Paolo Comeglio, Tommaso Mello, Daniele Bani, Daniele Guasti,
Erica Sarchielli, Annamaria Morelli, Elena Maneschi, Gabriella Barbara Vannelli
903
CXCL1 promotes steatohepatitis and fibrosis in a mouse
model of high-fat diet-plus-binge ethanol feeding
Zhou Zhou 1 , Ming-Jiang Xu 1 , Binxia Chang 1,2 , Yan Cai 1 , Bin
Gao 1 ; 1 Laboratory of Liver Diseases, National Institute of Alcohol
Abuse and Alcoholism, Rockville, MD; 2 Diagnosis and Treatment
Center for Non-Infectious Liver Diseases, Institute of Alcoholic Liver
Disease, Beijing 302 Hospital, Beijing, China
Background and Aims: Obesity and alcohol abuse are independent
risk factors of human liver diseases. Although some
epidemic studies suggested a synergistic effect, the exact function
and mechanism of liver lipid accumulation and alcohol
intake on liver injury is elusive. Methods: In our present study
we developed a murine model of high fat diet (HFD)-plus-binge
ethanol feeding. By using this model, we examined the role of
CXCL1 in steatohepatitis and fibrosis. Results: This HFD-plusbinge
ethanol feeding model induced significant steatohepatitis
and liver fibrosis, as demonstrated by increased expression
of collagen genes and obvious collagen deposition shown in
Sirius Red staining. When we analyzed the mechanisms, we
found that HFD-plus-binge resulted in a significant increase
of neutrophil infiltration in the liver by flow cytometry analysis
of Gr-1 hi CD11b + cells and immunohistochemistry staining of
MPO. Hepatic and serum CXCL1 levels were highly elevated
after HFD-plus-binge ethanol feeding. This upregulation was
mediated by free fatty acid accumulation and the downstream
ERK, JNK and NF-kB pathways. Blocking CXCL1 by genetic
disruption or a neutralizing antibody improved steatohepatitis.
In contrast, overexpressing CXCL1 in hepatocytes with adenovirus
induced significant liver inflammation and injury. Moreover,
hepatocyte derived CXCL1 also contributed to liver fibrosis.
Overexpression of CXCL1 in hepatocytes devastated collagen
deposition in HFD mice, while neutralizing CXCL1 ameliorated
fibrosis induced by HFD-plus-binge ethanol feeding. Conclusions:
Our results revealed a pivotal role of hepatocyte derived
CXCL1 in the liver damage and fibrosis caused by fatty liver
disease and alcohol abuse. Inhibiting the production of CXCL1
or blocking its function might be a useful therapeutic strategy in
preventing alcoholic hepatitis and the related fibrosis.
Disclosures:
The following authors have nothing to disclose: Zhou Zhou, Ming-Jiang Xu, Binxia
Chang, Yan Cai, Bin Gao
904
Vitamin D through Induction of Paneth Cell Defensins
Attenuates Gut Dysbiosis and Improves Metabolic Disorders
in Animal Models
Yuan-Ping Han 1 , Danmei Su 1 , Yuanyang Nie 1 , Airu Zhu 1 , Zishuo
Chen 1 , Li Zhang 1 , Pengfei Wu 1 , Mei Luo 1 , Guihui Wu 2 , Richard
Hu 3 , Aurelia Lugea 4 , Jun Xu 5 , Hidekazu Tsukamoto 5 , Stephen J.
Pandol 4 ; 1 College of Life Sciences, Sichuan University, Chengdu
City, China; 2 Chengdu Public Health Clinical Center, Chengdu,
China; 3 Olive View-UCLA Medical Center, Los Angeles, CA;
4 Cedars-Sinai Medical Center, Los Angeles, CA; 5 University of
Southern California, Los Angeles, CA
Metabolic syndrome (MetS) and vitamin D insufficiency/deficiency
are co-prevalent in general population worldwide, but
their causal relationship and mechanisms remain to be determined.
Large body of clinical surveys shows vitamin D insufficiency/deficiency
is associated with type-2 diabetes, obesity,
non-alcoholic steatohepatitis (NASH), and metabolic disorders.
Our previous work also demonstrated dietary vitamin D deficiency
promotes the high fat feeding initiated NASH, in part
through impaired enterohepatic circulation. Since vitamin D
receptor (VDR) is highly expressed in ileum epithelia, we tested
the role of vitamin D signaling in maintaining intestinal integrity
and eubiosis. Balb/C and C57/B6 mice were fed for 4-5
months by (1) AIN93 chow with vitamin D 3
supplementation
as control, or (2) AIN93 with vitamin D depletion, VDD, or (3)
high fat (60% calorie) with vitamin D supplementation, HFD,
and (4) high fat chow with vitamin D depletion, HFD+VDD.
Our results showed that HFD alone was not sufficient to induce
NASH and metabolic disorders, but additional dietary vitamin
D deficiency (HFD+VDD) resulted in severe NASH and insulin
resistance. The interface of ileum—being defined by the intestinal
epithelia and the adjacent gut microbiota in the lumen—
was impaired by the mice fed with HFD+VDD. Specifically, the
Paneth cell-specific defensins including a-defensin 5 (DEFA5),
MMP7 which activates defensins, tight junction genes, and
goblet cell produced mucous protein MUC2 were all thoroughly
suppressed or down regulated in the ileum, resulting
in mucosal collapse, gut leakiness, dysbiosis, endotoxemia,
systemic inflammation, insulin resistance, hepatic steatosis,
and metabolic disorders. Moreover, Helicobacter hepaticus,
a known murine hepatic-pathogen causing chronic hepatitis,
was substantially amplified in within the ileum of the mice fed
with HFD+VDD, while the beneficial symbiotic Akkermansia
muciniphila was diminished. Mice deficient in VDR exhibited
spontaneous NASH and very similar dysbiosis to the mice fed
with HFD+VDD. Remarkably, oral administration of DEFA5 to
the metabolic mice restored gut eubiosis, showing suppression
of Helicobacter hepaticus and reviving Akkermansia muciniphila
within the lumen of ileum, where VD signaling and DEFA5
were impaired by VDD. Along with rebalancing of gut microbiota,
oral administration of DEFA5 resolved hepatic steatosis
in the HFD+VDD fed mice. These results reveal the critical roles
of vitamin D/VDR pathway in optimal expression of defensins,
which in turn regulate intestinal integrity and eubiosis to protect
the host from metabolic disorders including NASH.
Disclosures:
Stephen J. Pandol - Consulting: Calcimedica, Shire, Takeda; Grant/Research
Support: NIH, Department of Veterans Affairs, Calcimedica; Stock Shareholder:
GIRx, Phyteau, Pandol Bros. Inc., Ranch 50