Anandamide inhibits cholangiocyte hyperplastic proliferation via activation of thioredoxin 1/redox factor 1 and AP-1 activation.
The endocannabinoid system regulates various aspects of hepatic fibrosis; however, nothing is known about its role in regulating cholangiocyte proliferation and function. We evaluated the effects of anandamide (AEA) on cholangiocyte proliferation and explored the effects of AEA on the thioredoxin 1 (TRX1)/redox factor 1 (Ref1)/activator protein-1 (AP-1) pathway. Mice underwent bile duct ligation (BDL) and were infused with AEA for 3 days postsurgery. Proliferation and apoptosis were evaluated in liver sections. Effects of in vitro AEA treatment on cholangiocyte proliferation and apoptosis were studied in purified cholangiocytes. The relative expression of cannabinoid receptors was also assessed in liver sections and cholangiocytes. mRNA expression of the cannabinoid receptors Cb1 and VR1 was decreased after BDL, whereas there was an upregulation of Cb2 mRNA. AEA decreased cholangiocyte growth and induced accumulation of reactive oxygen species, upregulation of TRX1, Ref1, c-Fos, and c-Jun expression, increased nuclear localization of TRX1, and increased AP-1 transcriptional activity. Specific knockdown of TRX1 or Ref1 expression ablated the AP-1 transcriptional activity and AEA-induced cell death but not expression of c-Fos and c-Jun. Knockdown of c-Fos and c-Jun expression also ablated AEA-induced apoptosis. We conclude that AEA suppresses cholangiocyte proliferation during cholestasis via a Cb2-dependent mechanism. Modulation of the endocannabinoid system may be important in the treatment of cholangiopathies.
DeMorrow
Sharon
S
Division of Research and Education, Scott & White Hospital, Temple, TX 76504, USA. demorrow@medicine.tamhsc.edu
Francis
Heather
H
Gaudio
Eugenio
E
Ueno
Yoshiyuki
Y
Venter
Julie
J
Onori
Paolo
P
Franchitto
Antonio
A
Vaculin
Bradley
B
Vaculin
Shelley
S
Alpini
Gianfranco
G
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001095:Arachidonic Acids / Q000494:pharmacology*; D001652:Bile Ducts / Q000166:cytology*; D001711:Biotransformation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D002469:Cell Separation; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism; D063388:Endocannabinoids; D016762:Genes, fos / Q000235:genetics; D016758:Genes, jun / Q000235:genetics; D006965:Hyperplasia / Q000473:pathology; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D053284:Polyunsaturated Alkamides / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D043882:Receptors, Cannabinoid / Q000096:biosynthesis; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D001095:Arachidonic Acids; D063388:Endocannabinoids; D053284:Polyunsaturated Alkamides; D017382:Reactive Oxygen Species; D043882:Receptors, Cannabinoid; D018808:Transcription Factor AP-1; D013879:Thioredoxins; D013880:Thioredoxin-Disulfide Reductase; C486216:Apex1 protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C078814:anandamide