studies

854A AASLD ABSTRACTS HEPATOLOGY, October, 2015
was a 4% difference in corticosteroid response between LM4
and LM7, the rate of responders that survived was unchanged
(36%). Whether earlier responders at day 4 have a favorable
prognosis need to be investigated.
Table-1 Operational characteristics of Lille Model on day 4 and
day 7
a known inhibitor of autophagy, and AMPK, that activates
autophagy due to dephosphorylation of these counter regulatory
signaling molecules. We also observed that the activity of
protein phosphatase 2A, a critical dephosphorylating enzyme,
increased while the activity of PI3Kγ, an upstream inhibitor of
PP2A, was reduced by alcohol.
Disclosures:
The following authors have nothing to disclose: Gangarao Davuluri, Samjhana
Thapaliya, Avinash Kumar, Megan R. McMullen, Rebecca L. McCullough, Laura
E. Nagy, Sathyamangla V. Naga Prasad, Srinivasan Dasarathy
Disclosures:
Andres Duarte-Rojo - Advisory Committees or Review Panels: Gilead Sciences;
Grant/Research Support: Vital Therapies; Speaking and Teaching: Roche
The following authors have nothing to disclose: Mauricio Garcia-Saenz de
Sicilia, Chitharanjan Duvoor, Jose Altamirano, Veronica Prado, Juan Caballeria
1308
Ethanol-impairs mTOR activity by a novel non-canonical
PI3Kγ-PP2A axis activating skeletal muscle autophagy
that underlies sarcopenia.
Gangarao Davuluri 2 , Samjhana Thapaliya 2 , Avinash Kumar 2 ,
Megan R. McMullen 2 , Rebecca L. McCullough 2 , Laura E. Nagy 2 ,
Sathyamangla V. Naga Prasad 3 , Srinivasan Dasarathy 1 ; 1 Department
Of Gastroenterology and Hepatology, Cleveland Clinic,
Cleveland, OH; 2 Pathobiology, Cleveland Clinic, Cleveland, OH;
3 Molecular Cardiology, Cleveland Clinic, Cleveland, OH
Background. Sarcopenia or loss of skeletal muscle mass in
alcoholic cirrhosis is frequent and contributes to morbidity and
mortality. No therapeutic interventions to reverse sarcopenia
in alcoholic cirrhosis exist because the mechanisms are poorly
understood. We have previously observed an alcohol mediated,
AMPK independent, PI3Kγ dependent inhibition of mTOR
signaling that activates skeletal muscle autophagy. In the present
studies we show that ethanol-induced mitochondrial reactive
oxygen species impairs mTOR activity by a novel non-canonical
PI3Kγ-protein phosphatase 2 A (PP2A) axis that is responsible
for increased skeletal muscle autophagy that underlies
sarcopenia. Methods. Skeletal muscle mass in patients and
controls and myotube diameter were quantified by image analysis.
Phosphorylation of AMPK, mTOR and its activity was measured
by Immunoblots of protein from C2C12 murine myotubes
exposed to 100 mM ethanol for 6 hr and skeletal muscle from
mice fed ethanol or pair fed for 25 days. Thin layer chromatography
blots for PI3Kγ activity was quantified in C2C12 myotubes
exposed to ethanol and gastrocnemius muscle from mice
fed ethanol or pair fed controls. Results. Here we report that
ethanol increases skeletal muscle autophagy in humans, mouse
models and murine myotubes with unaltered or reduced proteasome
activity and contributes to sarcopenia. The two major
regulators of autophagy are mTOR that inhibits autophagy and
AMPK that activates autophagy. Surprisingly, our data showed
that both mTOR signaling (autophagy inhibitor) and AMPK
activation (autophagy activation) were decreased in ethanol
treated myotubes and in mice exposed to ethanol. The surprising
signaling response via 2 pathways that converge on autophagy,
suggested that dephosphorylation may be a potential
mechanism for reduced phosphorylation of both mTOR and
AMPK. Consistently, we observed that skeletal muscle PP2A
activity was increased and was accompanied by a decreased
PI3Kγ activity, an inhibitor of PP2A. These data showed that
ethanol activates PP2A dependent dephosphorylation of mTOR
and AMPK. We confirmed this by using fostriecin, a PP2A
inhibitor, that reversed ethanol-induced inactivation of mTOR
and AMPK. Conclusions. Alcohol inhibits activation of mTOR,
1309
Differential Changes In Pro-Apoptotic Plasma Glycochenodeoxycholate
And Fecal Glycodeoxycholate Characterize
Bile Acid Metabolome In Alcoholic Liver Disease
Puneet Puri 2 , Andrew R. Joyce 1 , Amon Asgharpour 2 , Mohammad
S. Siddiqui 2 , Richard K. Sterling 2 , R. Todd Stravitz 2 , Velimir A.
Luketic 2 , Scott C. Matherly 2 , Kalyani Daita 2 , Susan A. Walker 2 ,
Stephanie Taylor 2 , Christian E. Ammons 2 , Faridoddin Mirshahi 2 ,
Arun J. Sanyal 2 ; 1 Venebio, Richmond, VA; 2 Virginia Commonwealth
University, Richmond, VA
BACKGROUND: Bile acid (BA) derangements are implicated
in the pathophysiology of alcoholic (ALD) and nonalcoholic
fatty liver disease (NAFLD). Two NAFLD phenotypes, fatty liver
(NAFL) and steatohepatitis (NASH) relate to disease severity.
Recently, a BA analogue showed encouraging therapeutic
potential for NASH. We hypothesized that ALD and NAFLD
are associated with dysregulated BA metabolism. AIMS: 1) To
characterize plasma and fecal BA metabolome compared to
controls (CTL), and 2) To evaluate BA metabolites as potential
biomarkers of ALD, NAFL and NASH. METHODS: Controls,
biopsy confirmed NAFL and NASH, and ALD subjects were
enrolled. Pertinent clinical data, plasma and stool samples
were collected. High throughput mass spectrometry was used
for metabolomics. Data were analyzed using pairwise and multiple
group comparisons by ANOVA, regularized Hotelling’s
T 2 , and partial least square discriminant analysis with variable
importance projection (VIP) scores. A VIP score >1 is significant.
Higher VIP score indicates importance of that variable contributing
to the change. RESULTS: Four groups with mean(±SD)
age (yrs): CTL (n=24, 39±12), NAFL (n=22, 53±10), NASH
(n=37, 58±9) and ALD (n=18, 50±11) were studied. Plasma
BA metabolome: ALD subjects had markedly increased total
primary (p