Aims: The purpose of this study was to determine whether 3¢-5¢-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) and Sirtuin-1 (SIRT1) dependent mechanisms modulate ATP-binding Cassette (ABC) transport protein expression. ABC transport proteins (ABCC2-4) are essential for chemical elimination from hepatocytes and biliary excretion. Nuclear factor-E2 related-factor 2 (NRF2) is a transcription factor that mediates ABCC induction in response to chemical inducers and liver injury. However, a role for NRF2 in the regulation of transporter expression in nonchemical models of liver perturbation is largely undescribed. Results: Here we show that fasting increased NRF2 target gene expression through NRF2-and SIRT1-dependent mechanisms. In intact mouse liver, fasting induces NRF2 target gene expression by at least 1.5 to 5-fold. In mouse and human hepatocytes, treatment with 8-Bromoadenosine-cAMP, a cAMP analogue, increased NRF2 target gene expression and antioxidant response element activity, which was decreased by the PKA inhibitor, H-89. Moreover, fasting induced NRF2 target gene expression was decreased in liver and hepatocytes of SIRT1 liver-specific null mice and NRF2-null mice. Lastly, NRF2 and SIRT1 were recruited to MAREs and Antioxidant Response Elements (AREs) in the human ABCC2 promoter. Innovation: Oxidative stress mediated NRF2 activation is well described, yet the influence of basic metabolic processes on NRF2 activation is just emerging. Conclusion: The current data point toward a novel role of nutrient status in regulation of NRF2 activity and the antioxidant response, and indicates that cAMP/PKA and SIRT1 are upstream regulators for fasting-induced activation of the NRF2-ARE pathway. Antioxid. Redox Signal. 20,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]

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Background Cholestasis is a common disease of the liver. Chronic cholestasis eventually leads to hepatic cirrhosis and fibrosis, and rodent chronic cholestasis models are used to study aspects of fibrosis and cirrhosis. Cholestasis-induced liver injury and fibrosis are associated with increased oxidative stress and inflammation. Few pharmacological therapies exist for treatment of cholestasis or cirrhosis, but it is known that humans with better nutritional intake are less likely to develop certain types of cirrhosis. Eugenia jambolana (Jamun) is a tropical berry fruit rich in antioxidant anthocyanin compounds. Aim Because anthocyanins decrease cellular lipid peroxidation and oxidative stress, it was hypothesized that Jamun fruit extract (JFE) administration could protect against cholestatic liver injury and inflammation in mice. Method Starting 24 h after sham or bile-duct ligation (BDL) surgery, male C57Bl/6 mice were administered vehicle or JFE (100 mg/kg, po) for ten days. Results Mice that underwent BDL had elevated serum ALT levels, which were reduced 60% by JFE treatment. Likewise, BDL caused hepatic inflammation, macrophage infiltration, fibrosis, and necrosis, all of which were largely improved by JFE. Interestingly, hepatoprotection was observed in JFE-treated BDL mice, despite suppressed transporter expression and increased hepatic bile acid concentrations. Conclusion Jamun fruit phytochemicals decreased hepatic inflammation and oxidative stress, and protected against hepatocellular injury in mice. Jamun warrants further investigation as a potential antioxidant/anti-inflammatory therapy to treat not only cholestasis, but also other liver diseases with an inflammatory component.

Hemolysins produced by Vibrio anguillarum have been implicated in the development of hemorrhagic septicemia during vibriosis, a fatal fish disease. Previously, two hemolysin gene clusters responsible for the hemolysis and cytotoxicity of V. anguillarum were identified: the vah1-plp gene cluster and the rtxACHBDE gene cluster. In this study, we identified the hns gene, which encodes the H-NS protein and acts as a negative regulator of both gene clusters. The V. anguillarum H-NS protein shares strong homology with other bacterial H-NS proteins. An hns mutant exhibited increased hemolytic activity and cytotoxicity compared to the wild-type strain. Complementation of the hns mutation restored hemolytic activity and cytotoxicity levels to nearly wildtype levels. Furthermore, expression of rtxA, rtxH, rtxB, vah1, and plp increased in the hns mutant and decreased in the hnscomplemented mutant strain compared to expression in the wild-type strain. Additionally, experiments using DNase I showed that purified recombinant H-NS protected multiple sites in the promoter regions of both gene clusters. The hns mutant also exhibited significantly attenuated virulence against rainbow trout. Complementation of the hns mutation restored virulence to wild-type levels, suggesting that H-NS regulates many genes that affect fitness and virulence. Previously, we showed that HlyU is a positive regulator of expression for both gene clusters. In this study, we demonstrate that upregulation by hlyU is hns dependent, suggesting that H-NS acts to repress or silence both gene clusters and HlyU acts to relieve that repression or silencing. Vibrio anguillarum is the causative agent of vibriosis, a fatal hemorrhagic septicemic disease. V. anguillarum infects more than 50 fresh-and saltwater fish species, including various species of economic importance to the larviculture and aquaculture industries, such as salmon, rainbow trout, turbot, sea bass, sea bream, cod, eel, and ayu (1). Infections by this bacterium have mortality rates of 30% to 100%, resulting in severe economic losses to aquaculture worldwide (2).The ability of V. anguillarum to infect and cause disease in fish is dependent upon several virulence factors and their proper regulation (3). One of these virulence factors is hemolytic activity. In V. anguillarum M93Sm, there are two known gene clusters that encode at least three hemolysins (4, 5). Rock and Nelson (4) reported that the vah1-plp hemolysin gene cluster (Fig. 1A) contains at least two genes, vah1 and plp, that affect hemolytic activity. Vah1 (encoded by vah1) is a putative pore-forming hemolysin causing vacuolization of target cells that has strong amino acid sequence identity to Vibrio cholerae El Tor hemolysin (hlyA) and V. fluvialis hemolysin (5). Mutations in the divergently transcribed plp gene result in both increased expression of vah1 and increased hemolysis of sheep's blood, suggesting that Plp (encoded by plp) is a putative repressor of vah1 transcription (4). Restoration of plp by complementation restores the wild-...

Deltamethrin, a type II pyrethroid, is a widely used insecticide. The purpose of this study was to determine whether perinatal deltamethrin exposure altered the expression of adipogenic and lipogenic genes in white adipose tissue (WAT) in adult pups. C57BL/6 pregnant mice were administered 0, 1, or 3 mg/kg of deltamethrin orally every 3 days throughout gestation and lactation. Offspring were weaned on postnatal day 25, and WAT was collected from 5-month-old male mice. Perinatal deltamethrin exposure decreased the mRNA expression of adipogenesis-related transcription factors Pparγ, Cebpα, and lipogenic genes Srebp1c, Acc-1, Cd36, Lpl, Scd-1; along with Nrf2 and target genes Nqo1 and Gclc at the 1 mg/kg treatment. Cytokine expression of Fas/Tnf-R and Cd209e at the 1 mg/kg treatment was significantly decreased, and expression of Tnf, Cd11c, and Fas/Tnf-R was decreased at the 3 mg/kg treatment. Developmental deltamethrin exposure did not overtly affect body weight or adipose weight, but decreased mRNA expression of specific genes that may poten tially disrupt normal adipogenesis and lipid and glucose metabolism if the offspring are challenged by changes in diet or environment.