title: HIV infection increases HCV-induced hepatocyte apoptosis.
abstract: OBJECTIVE
  HCV related liver disease is one of the most important complications in persons with HIV, with accelerated fibrosis progression in coinfected persons compared to those with HCV alone. We hypothesized that HCV-HIV coinfection increases HCV related hepatocyte apoptosis and that HCV and HIV influence TRAIL signaling in hepatocytes.
  
  
  METHODS
  We analyzed the effect of HIV in JFH1-infected Huh7.5.1 cells. Apoptosis was measured by Caspase-Glo 3/7 assay and Western blotting for cleaved PARP. TRAIL, TRAIL receptor 1 (DR4), and 2 (DR5) mRNA and protein levels were assessed by real-time PCR and Western blot, respectively. We also investigated activation of caspase pathways using caspase inhibitors and assessed expression of Bid and cytochrome C.
  
  
  RESULTS
  We found increased caspase 3/7 activity and cleaved PARP in JFH1 HCV-infected Huh7.5.1 cells in the presence of heat-inactivated HIV, compared to Huh7.5.1 cells infected with JFH1 or exposed to heat-inactivated HIV alone. Both DR4 and DR5 mRNA and protein expression were increased in JFH1-infected cells in the presence of inactivated HIV compared to Huh7.5.1 cells infected with JFH1 or exposed to heat-inactivated HIV alone. Pancaspase, caspase-8, and caspase-9 inhibition blocked apoptosis induced by HCV, inactivated HIV, and HCV plus inactivated HIV. A caspase-9 inhibitor blocked apoptosis induced by HCV, HIV, and HCV-HIV comparably to pancaspase and caspase-8 inhibitors. HCV induced the activation of Bid cleavage and cytochrome C release. The addition of HIV substantially augmented this induction.
  
  
  CONCLUSIONS
  Our findings indicate that hepatocyte apoptosis is increased in the presence of HCV and HIV compared to HCV or HIV alone, and that this increase is mediated by DR4 and DR5 up-regulation. These results provide an additional mechanism for the accelerated liver disease progression observed in HCV-HIV co-infection.
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Run-Xuan
authors.initials: RX
authors.lastname: Shao
authors.forename: Wenyu
authors.initials: W
authors.lastname: Lin
authors.forename: Ethan
authors.initials: E
authors.lastname: Weinberg
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Chung
authors.forename: Wei Lun
authors.initials: WL
authors.lastname: Tsai
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Kaku
authors.initials: K
authors.lastname: Goto
authors.forename: Leiliang
authors.initials: L
authors.lastname: Zhang
authors.forename: Jorge
authors.initials: J
authors.lastname: Mendez-Navarro
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Jilg
authors.forename: Lee F
authors.initials: LF
authors.lastname: Peng
authors.forename: Mark A
authors.initials: MA
authors.lastname: Brockman
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Chung
mesh_terms: D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D001483:Base Sequence; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D015658:HIV Infections / Q000150:complications* / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000472:pathogenicity*; D019698:Hepatitis C, Chronic / Q000150:complications* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000378:metabolism
chemical_list: D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D017931:DNA Primers; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505653:TNFSF10 protein, human; D045304:Cytochromes c; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053148:Caspase 3; D053179:Caspase 7