GUDC inhibits cytochrome c release from human cholangiocyte mitochondria

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Although ursodeoxycholic acid (UDC) is considered effective treatment for primary biliary cirrhosis (PBC), its mechanism of action is unclear. We tested the hypothesis that UDC is taken up by cholangiocytes and inhibits caspase 3-dependent apoptosis. We used the human cholangiocyte cell line (H69) and assessed it for expression and function of an apical sodium- dependent bile acid transporter (ASBT) by RT-PCR and uptake of tritiated taurocholic acid. We experimentally induced apoptosis in H69 cells using beauvericin (BV) and determined caspase 3 activation using a fluorogenic substrate and mitochondrial cytochrome c release (CC) into the cytosol by immunoblot analysis. We found that a functional ASBT is expressed by H69 cells as demonstrated by RT-PCR and bile acid uptake studies. Exposure of H69 cells to BV induced apoptosis in 39.4 ± 1.3% of cells at 2 h (0.23 ± 0.2% in controls). In contrast, when H69 cells were preincubated with GUDC (50 mM) for 24 h and then exposed to BV, apoptosis was inhibited by 23% (P < 0.03). In cholangiocytes pretreated with GUDC for 24 h and those treated with BV for 2 h, caspase 3-like activity was reduced by 79% and mitochondrial CC release was inhibited. In summary, the human cholangiocyte cell line H69 possesses a functional bile acid transporter, and GUDC decreases BV-induced apoptosis and inhibits activity of caspase 3 protease by blocking CC release from mitochondria. These preliminary results are consistent with our hypothesis that the beneficial effect of UDC on PBC may involve decreased apoptosis after GUDC uptake by cholangiocytes.

Original languageEnglish (US)
Pages (from-to)100-105
Number of pages6
JournalJournal of Surgical Research
Volume83
Issue number2
DOIs
StatePublished - May 15 1999

Fingerprint

Cytochromes c
Mitochondria
Apoptosis
Ursodeoxycholic Acid
Caspase 3
Biliary Liver Cirrhosis
Cell Line
Polymerase Chain Reaction
Taurocholic Acid
Bile Acids and Salts
Fluorescent Dyes
Cytosol
Peptide Hydrolases
beauvericin

Keywords

  • Beauvericin
  • Caspase
  • Caspase 3
  • Cholangiocytes
  • Cytochrome c
  • Fluorogenic caspase protease substrates

ASJC Scopus subject areas

  • Surgery

Cite this

GUDC inhibits cytochrome c release from human cholangiocyte mitochondria. / Que, Florencia; Phan, Vy A.; Phan, Van H.; La Russo, Nicholas F; Gores, Gregory James.

In: Journal of Surgical Research, Vol. 83, No. 2, 15.05.1999, p. 100-105.

Research output: Contribution to journalArticle

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abstract = "Although ursodeoxycholic acid (UDC) is considered effective treatment for primary biliary cirrhosis (PBC), its mechanism of action is unclear. We tested the hypothesis that UDC is taken up by cholangiocytes and inhibits caspase 3-dependent apoptosis. We used the human cholangiocyte cell line (H69) and assessed it for expression and function of an apical sodium- dependent bile acid transporter (ASBT) by RT-PCR and uptake of tritiated taurocholic acid. We experimentally induced apoptosis in H69 cells using beauvericin (BV) and determined caspase 3 activation using a fluorogenic substrate and mitochondrial cytochrome c release (CC) into the cytosol by immunoblot analysis. We found that a functional ASBT is expressed by H69 cells as demonstrated by RT-PCR and bile acid uptake studies. Exposure of H69 cells to BV induced apoptosis in 39.4 ± 1.3{\%} of cells at 2 h (0.23 ± 0.2{\%} in controls). In contrast, when H69 cells were preincubated with GUDC (50 mM) for 24 h and then exposed to BV, apoptosis was inhibited by 23{\%} (P < 0.03). In cholangiocytes pretreated with GUDC for 24 h and those treated with BV for 2 h, caspase 3-like activity was reduced by 79{\%} and mitochondrial CC release was inhibited. In summary, the human cholangiocyte cell line H69 possesses a functional bile acid transporter, and GUDC decreases BV-induced apoptosis and inhibits activity of caspase 3 protease by blocking CC release from mitochondria. These preliminary results are consistent with our hypothesis that the beneficial effect of UDC on PBC may involve decreased apoptosis after GUDC uptake by cholangiocytes.",
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AU - Que, Florencia

AU - Phan, Vy A.

AU - Phan, Van H.

AU - La Russo, Nicholas F

AU - Gores, Gregory James

PY - 1999/5/15

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N2 - Although ursodeoxycholic acid (UDC) is considered effective treatment for primary biliary cirrhosis (PBC), its mechanism of action is unclear. We tested the hypothesis that UDC is taken up by cholangiocytes and inhibits caspase 3-dependent apoptosis. We used the human cholangiocyte cell line (H69) and assessed it for expression and function of an apical sodium- dependent bile acid transporter (ASBT) by RT-PCR and uptake of tritiated taurocholic acid. We experimentally induced apoptosis in H69 cells using beauvericin (BV) and determined caspase 3 activation using a fluorogenic substrate and mitochondrial cytochrome c release (CC) into the cytosol by immunoblot analysis. We found that a functional ASBT is expressed by H69 cells as demonstrated by RT-PCR and bile acid uptake studies. Exposure of H69 cells to BV induced apoptosis in 39.4 ± 1.3% of cells at 2 h (0.23 ± 0.2% in controls). In contrast, when H69 cells were preincubated with GUDC (50 mM) for 24 h and then exposed to BV, apoptosis was inhibited by 23% (P < 0.03). In cholangiocytes pretreated with GUDC for 24 h and those treated with BV for 2 h, caspase 3-like activity was reduced by 79% and mitochondrial CC release was inhibited. In summary, the human cholangiocyte cell line H69 possesses a functional bile acid transporter, and GUDC decreases BV-induced apoptosis and inhibits activity of caspase 3 protease by blocking CC release from mitochondria. These preliminary results are consistent with our hypothesis that the beneficial effect of UDC on PBC may involve decreased apoptosis after GUDC uptake by cholangiocytes.

AB - Although ursodeoxycholic acid (UDC) is considered effective treatment for primary biliary cirrhosis (PBC), its mechanism of action is unclear. We tested the hypothesis that UDC is taken up by cholangiocytes and inhibits caspase 3-dependent apoptosis. We used the human cholangiocyte cell line (H69) and assessed it for expression and function of an apical sodium- dependent bile acid transporter (ASBT) by RT-PCR and uptake of tritiated taurocholic acid. We experimentally induced apoptosis in H69 cells using beauvericin (BV) and determined caspase 3 activation using a fluorogenic substrate and mitochondrial cytochrome c release (CC) into the cytosol by immunoblot analysis. We found that a functional ASBT is expressed by H69 cells as demonstrated by RT-PCR and bile acid uptake studies. Exposure of H69 cells to BV induced apoptosis in 39.4 ± 1.3% of cells at 2 h (0.23 ± 0.2% in controls). In contrast, when H69 cells were preincubated with GUDC (50 mM) for 24 h and then exposed to BV, apoptosis was inhibited by 23% (P < 0.03). In cholangiocytes pretreated with GUDC for 24 h and those treated with BV for 2 h, caspase 3-like activity was reduced by 79% and mitochondrial CC release was inhibited. In summary, the human cholangiocyte cell line H69 possesses a functional bile acid transporter, and GUDC decreases BV-induced apoptosis and inhibits activity of caspase 3 protease by blocking CC release from mitochondria. These preliminary results are consistent with our hypothesis that the beneficial effect of UDC on PBC may involve decreased apoptosis after GUDC uptake by cholangiocytes.

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