Kinases are intracellular signalling enzymes that drive many physiological and physiopathological processes, and represent appealing “druggable” targets for therapy. The aim of the current study is to identify which kinases are involved in the pathogenesis of AH by performing a proteomic analysis based on modern high-throughput molecular techniques such as Reversed-ELISA. The results identified p90RSK as one of the most activated kinases in patients with AH. Methods: Whole protein extracts were obtained from patients with biopsy-proven AH (n=12) and fragments of normal livers (n=7). Sixty-three ZD1839 clinical trial analytes were analyzed by Reversed-ELISA. Gene and protein expression of p90RSK were assessed by quantitative

PCR, Western blotting and immunohistochemistry in patients with different types of liver disease. Furthermore, pharmacological inhibition of p90RSK by kaempferol, a natural inhibitor of p90RSK, was performed in two experimental approaches. First, in an in vivo approach using a mouse model of chronic liver injury by carbon tetrachloride (CCl4) administration and second,

in an in vitro approach using primary human hepatic stellate cells (HSC) and primary mouse hepatocytes in culture. Results: Eighteen proteins were differentially expressed in samples from patients with AH compared to normal livers, including STAT3, p38, mTO R and Akt. Importantly, p90RSK -a ribosomal S6 kinase- was significantly more phosphorylated in its Ser380 residue in patients with AH compared to controls (p<0.01). BGJ398 purchase p90RSK hepatic gene and protein expression and phosphorylation were found increased in patients with liver disease including patients with AH, hepatitis C virus (HCV) and cirrhosis compared to controls (p < 0.01 for all). Next, p90RSK inhibition medchemexpress by kaempferol attenuated fibrosis progression in CCl4-treated mice as shown by reduced expression of pro-fibrogenic genes and inflammatory cytokines, and reduced hepatic collagen deposition. Kaempferol also reduced activation of primary HSC in culture and showed protection against apoptotic mediators in primary cultured hepatocytes. Conclusions: Translational studies using a proteomic analysis on human samples identified

p90RSK as a possible mediator in the pathogenesis of AH. Importantly, inhibition of p90RSK attenuates liver inflammation, fibrosis and injury. These results suggest that p90RSK could be a novel target for patients with AH. Disclosures: Vicente Arroyo – Speaking and Teaching: GRIFOLS Pere Gines – Advisory Committees or Review Panels: Ferring; Grant/Research Support: Sequana Medical, Grifols The following people have nothing to disclose: Oriol Morales-Ibanez, Silvia Affó, Daniel Rodrigo-Torres, Cristina Millán, Montserrat Moreno, Juan Caballeria, Pau Sancho-Bru, Ramon Bataller Purpose: Liver injury causes activation of hepatic stellate cells (HSCs), key players in fibrogenesis. Methionine adenosyltransferases (MAT) catalyze biosynthesis of S-adenosylmethionine (SAMe), a methyl donor.