MAPK signaling contributes to rotaviral-induced cholangiocyte injury and viral replication.
BACKGROUND
Biliary atresia is a disease of newborns that results in obliteration of the biliary tree. Infection of mice with rhesus rotavirus (RRV) results in a cholangiopathy mirroring human disease. The Mitogen Associated Protein Kinase (MAPK) signaling pathway can be activated by viral binding to cell-surface receptors. We hypothesized that RRV infection of cholangiocytes results in activation of MAPK signaling.


METHODS
Extrahepatic bile ducts from BALB/c pups or immortalized cholangiocytes subjected to RRV infection or control were analyzed, using Western blots, for phosphorylated members of the MAPK family: p38, ERK 1/2, JNK 1/2, and downstream transcription factors. Inhibitors of the MAPK were used to downregulate activity. Viral replication and cytolysis in cholangiocytes were evaluated post-MAPK inhibition.


RESULTS
Phosphorylation of all MAPK increased in RRV-infected mice and cholangiocytes. Several downstream transcription factors had increased activity in vitro. Inhibition of p38 and ERK 1/2 resulted in decreased viral replication. ERK 1/2 inhibition decreased cytolysis without affecting viral entry or binding.


CONCLUSIONS
RRV infection of cholangiocytes resulted in increased MAPK signaling. Inhibition of p38 and ERK 1/2 influenced the ability of rotavirus to replicate. These novel findings provide insight into the signaling cascade involved in RRV-induced cholangiocyte injury.
Jafri
Mubeen
M
Department of Pediatric and Thoracic Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Donnelly
Bryan
B
McNeal
Monica
M
Ward
Richard
R
Tiao
Greg
G
D000818:Animals; D017734:Bile Ducts, Extrahepatic / Q000166:cytology / Q000821:virology; D001656:Biliary Atresia / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D002461:Cell Line, Transformed; D004195:Disease Models, Animal; D005260:Female; D066298:In Vitro Techniques; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012401:Rotavirus / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D012400:Rotavirus Infections / Q000150:complications / Q000378:metabolism* / Q000821:virology*; D014157:Transcription Factors / Q000378:metabolism; D014774:Virulence; D014779:Virus Replication
D047428:Protein Kinase Inhibitors; D014157:Transcription Factors