Rat Hepatocyte Aquaporin–8 Water Channels Are Down–Regulated in Extrahepatic Cholestasis

Carreras, Flavia I.

doi:10.1053/jhep.2003.50170

Cited by 72 publications

(75 citation statements)

References 37 publications

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“…While T3 alone stimulated expression of AQP9 mRNA, there appeared to be no coordinate induction of protein synthesis or accumulation as a consequence of T3 stimulation. Lack of correlation between protein levels and gene expression has been well documented in several systems [23][24][25] and recently it has been shown that while bile duct ligation depressed the levels of AQP8 in rat liver, gene expression was actually enhanced [26]. These data suggest that analysis of changes in mRNA levels does not necessarily reflect or predict changes in AQP protein levels or how cell function might be altered.…”

Section: Discussionmentioning

confidence: 93%

Identification and characterization of aquaporin-9 (AQP9) in porcine hepatic tissue and hepatocytes in monolayer culture

Caperna

Shannon

Richards

et al. 2007

Domestic Animal Endocrinology

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Aquaporins (AQPs) are members of a large family of integral membrane proteins involved in the rapid movement of water and neutral solutes across cell membranes. In this study, we have prepared an affinity-purified porcine-specific polyclonal antiserum to AQP9 and have investigated the distribution and expression of AQP9 in pig liver tissue and in hepatocytes in primary culture. Immunocytochemical analysis showed that AQP9 was primarily localized in the membrane structures of hepatocytes and was not associated with intrahepatic bile ducts or blood vessels. Western blot analysis indicated that AQP9 ranged in apparent molecular mass between 27 and 38 kD in whole liver and hepatocyte membrane fractions; minor components were also observed at approximately 34 kD in the cytosol compartment of hepatocytes, bile duct and gall bladder. A prominent immunoreactive band at 44 kD was shown to be an artifact of Western blot analysis. In primary cultures of porcine hepatocytes, glucagon enhanced absolute levels of AQP9 protein, while gene expression was enhanced by T3 and glucagon. Insulin alone had no discernable influence on AQP9 gene expression or its cellular protein levels. These data ଝ Mention of trade name, proprietary product or vendor does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture or imply its approval to the exclusion of other products or vendors that also may be suitable.* This article is a U.S. government work, and is not subject to copyright in the United States. 274T.J. Caperna et al. / Domestic Animal Endocrinology 32 (2007) [273][274][275][276][277][278][279][280][281][282][283][284][285][286] suggest that AQP9 is a major AQP in porcine hepatic tissue and appears to be primarily responsive to glucagon induction.

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Section: Discussionmentioning

confidence: 93%

Identification and characterization of aquaporin-9 (AQP9) in porcine hepatic tissue and hepatocytes in monolayer culture

Caperna

Shannon

Richards

et al. 2007

Domestic Animal Endocrinology

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“…In addition to the regulated food intake aquaporin-8 a water channel which is mainly localized in the intracellular vesicles of hepatocytes and facilitates osmotic water movement during canalicular bile secretion is downregulated. 13 Similarly the genes which play important role in the transport of lipids and cholesterol (Slc27a5 and Npc1) and oxygen (Hba-a1) are also downregulated. 14,15 The differential expression of the above genes implies that the metabolic functions in the regenerating liver are carried out at a reduced sub-optimal level at the onset of DNA synthesis.…”

Section: Resultsmentioning

confidence: 99%

Gene Expression Profile at the G1/S Transition of Liver Regeneration after Partial Hepatectomy in Mice

et al. 2004

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Liver is a quiescent organ with >90% of the cells present in the G 0 stage of the cell cycle. However, adult hepatocytes have enormous ability to proliferate in response to liver injury. After 70% liver resection hepatocytes enter the cell cycle in a highly synchronized manner and undergo 1 to 2 rounds of cell division to restore the lost organ mass, thus, representing one of the most reliable model systems to study cell cycle progression in vivo. Using high density oligonucleotide micro-array we analyzed the expression patterns of genes at the G 1 /S transition of liver regeneration in comparison to quiescent livers. The G 1 /S boundary was identified by in vivo BrdU pulse labeling and we observed 199 genes/ESTs which were either up/down regulated at this time point. These differentially regulated genes have a wide range of functions including transcriptional regulation, signal transduction, cell cycle regulation, chromatin reorganization, protein targeting, metabolism, transport, surface receptors, circadian rhythms, xenobiotic metabolism, inflammation and acute phase response. The functions of most of the genes identified in this screen are not known in the process of liver regeneration and cell cycle control at G 1 /S transition.

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“…In separate experiments, we tested the effect of UB (17.1 μM) by exposing the cells for 15 min to the pigment, previous to the incubation with tBuOOH (100 μM) for 15 min or its solvent. Cytosolic (supernatant) and total membrane (pellet)-enriched fractions were obtained by ultracentrifugation for 60 min at 100,000 × g (Carreras et al 2003) and total protein determined (Lowry et al 1951). Proteins were separated by electrophoresis on a 12%-SDS-polyacrylamide gel and after electrotransfer, nitrocellulose membranes (Immobilon-P membranes) were incubated overnight with a mouse monoclonal antibody to PKCα (BD Biosciences Pharmingen; 1:1,000).…”

Section: Assessment Of Biliary Secretion Of Bile Salts Anddinitrophenmentioning

confidence: 99%

Physiological concentrations of unconjugated bilirubin prevent oxidative stress-induced hepatocanalicular dysfunction and cholestasis

et al. 2013

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Bilirubin is an endogenous antioxidant with cytoprotective properties, and several studies highlight its potential in the treatment of pro-oxidant diseases. We demonstrated that oxidative stress (OS), a key feature in most hepatopathies, induces cholestasis by actin cytoskeleton disarrangement and further endocytic internalization of key canalicular transporters, such as the bile salt export pump (Bsep) and the multidrug resistance-associated protein 2 (Mrp2). Here, we evaluated the capability of physiological concentrations of unconjugated bilirubin (UB)

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Rat Hepatocyte Aquaporin–8 Water Channels Are Down–Regulated in Extrahepatic Cholestasis

Cited by 72 publications

References 37 publications

Identification and characterization of aquaporin-9 (AQP9) in porcine hepatic tissue and hepatocytes in monolayer culture

Identification and characterization of aquaporin-9 (AQP9) in porcine hepatic tissue and hepatocytes in monolayer culture

Gene Expression Profile at the G1/S Transition of Liver Regeneration after Partial Hepatectomy in Mice

Physiological concentrations of unconjugated bilirubin prevent oxidative stress-induced hepatocanalicular dysfunction and cholestasis

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