Abstract

Using cell biological, biochemical, biophysical and immunomorphological methods, we seek to continue studies of the mechanisms involved in the transfer of bilirubin and other organic anions from blood to bile. (1) The role of hepatic endothelial cell fenestrae in controlling the uptake of bilirubin and other substances will be studied based upon characterization of fenestral dynamics in culture and effects on uptake mechanisms in isolated perfused rat liver. (2) Unique peptides from different isoforms of UDP glucuronyl transferase from normal and mutant (Gunn) rats will be sequenced and used for synthesis of oligonucleotide probes to identify isoform-specific cDNAs; the long range goal is to correct defective bilirubin UDPGI activity in Gunn rats and patients with the Crigler-Najjar syndrome, Type I. (3) Study of cellular mechanisms involved in cholestasis will be performed using isolated hepatocytes and vesicles derived from the sinusoidal and canalicular domains of the plasma membrane of hepatocytes; specifically, the role of membrane lipids, fluidity, polarity and the relation between transport events in the sinusoidal domain and observed defects in canalicular structure and function. A novel hypothesis that a group of canalicular plasma membrane ecto-""""""""ATPases"""""""" protect hepatocytes from extracellular ATP concentrations will also be tested. (4) Functional and structural studies will be performed using sinusoidal and canalicular plasma membrane vesicles from animals with autosomal recessively inherited defects in membrane transport affecting bilirubin and other organic anions. The group includes heterozygotes and homozygotes for an """"""""uptake defect"""""""" in Southdown sheep, the Dubin-Johnson syndrome in Corriedale sheep, and newly described conjugated hyperbilirubinemia in Wistar rats and cholestasis in homozygous athymic:heterozygous Gunn rat hybrids after administration of ethinyl estradiol. The goal is to define basic transport defects in these mutants.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37DK035652-06
Application #
3483690
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1984-12-01
Project End
1991-11-30
Budget Start
1990-01-01
Budget End
1990-11-30
Support Year
6
Fiscal Year
1990
Total Cost
Indirect Cost

  Institution

Name
Tufts University
Department
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02111

  Publications

Kagawa, Tatehiro; Watanabe, Norihito; Mochizuki, Kaori et al. (2008) Phenotypic differences in PFIC2 and BRIC2 correlate with protein stability of mutant Bsep and impaired taurocholate secretion in MDCK II cells. Am J Physiol Gastrointest Liver Physiol 294:G58-67
Mochizuki, Kaori; Kagawa, Tatehiro; Numari, Asano et al. (2007) Two N-linked glycans are required to maintain the transport activity of the bile salt export pump (ABCB11) in MDCK II cells. Am J Physiol Gastrointest Liver Physiol 292:G818-28
Wakabayashi, Yoshiyuki; Kipp, Helmut; Arias, Irwin M (2006) Transporters on demand: intracellular reservoirs and cycling of bile canalicular ABC transporters. J Biol Chem 281:27669-73
Wakabayashi, Yoshiyuki; Dutt, Parmesh; Lippincott-Schwartz, Jennifer et al. (2005) Rab11a and myosin Vb are required for bile canalicular formation in WIF-B9 cells. Proc Natl Acad Sci U S A 102:15087-92
Wakabayashi, Yoshiyuki; Lippincott-Schwartz, Jennifer; Arias, Irwin M (2004) Intracellular trafficking of bile salt export pump (ABCB11) in polarized hepatic cells: constitutive cycling between the canalicular membrane and rab11-positive endosomes. Mol Biol Cell 15:3485-96
Misra, Suniti; Varticovski, Lyuba; Arias, Irwin M (2003) Mechanisms by which cAMP increases bile acid secretion in rat liver and canalicular membrane vesicles. Am J Physiol Gastrointest Liver Physiol 285:G316-24
Kipp, Helmut; Arias, Irwin M (2002) Trafficking of canalicular ABC transporters in hepatocytes. Annu Rev Physiol 64:595-608
Ujhazy, P; Ortiz, D; Misra, S et al. (2001) Familial intrahepatic cholestasis 1: studies of localization and function. Hepatology 34:768-75
Kipp, H; Pichetshote, N; Arias, I M (2001) Transporters on demand: intrahepatic pools of canalicular ATP binding cassette transporters in rat liver. J Biol Chem 276:7218-24
Kipp, H; Arias, I M (2000) Intracellular trafficking and regulation of canalicular ATP-binding cassette transporters. Semin Liver Dis 20:339-51

Showing the most recent 10 out of 52 publications