title: Anti-hepatitis B virus (HBV) response of imiquimod based toll like receptor 7 ligand in hbv-positive human hepatocelluar carcinoma cell line.
abstract: Toll like receptors (TLRs) play an important role in innate immunity and various studies suggest that TLRs play a crucial role in pathogenesis of hepatitis B virus (HBV) infection. The present study aims in looking into the status of crucial host and viral gene expression on inciting TLR7.
  
  
  
  The transcription of TLR7 pathway signaling molecules and HBV DNA viral load were quantified by Real Time-PCR after stimulation of TLR7 with its imiquimod based ligand, R837. Cell cycle analysis was performed using flow-cytometry. Expression of TLR7 and chief cell cycle regulator governing G1/S transition, p53 was also seen in liver biopsysss samples of CHB patients. HBV induced alteration in histone modifications in HepG2 cells and its restoration on TLR7 activation was determined using western blot.
  
  
  
  The TLR7 expression remains downregulated in HepG2.2.15 cells and in liver biopsy samples from CHB patients. Interestingly HBV DNA viral load showed an inverse relationship with the TLR7 expression in the biopsy samples. We also evaluated the anti-viral activity of R837, an agonist of TLR7. It was observed that there was a suppression of HBV replication and viral protein production upon TLR7 stimulation. R837 triggers the anti-viral action probably through the Jun N-terminal Kinase (JNK) pathway. We also observed a downregulation of histone H3K9Me3 repression mark upon R837 treatment in HBV replicating HepG2.2.15 cells, mimicking that of un-infected HepG2 cells. Additionally, the G1/S cell cycle arrest introduced by HBV in HepG2.2.15 cells was released upon ligand treatment.
  
  
  
  The study thus holds a close insight into the changes in hepatocyte micro-environment on TLR7 stimulation in HBV infection.
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India.
authors.forename: Dipanwita
authors.initials: D
authors.lastname: Das
authors.affiliation: Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India.
authors.forename: Isha
authors.initials: I
authors.lastname: Sengupta
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India.
authors.forename: Neelakshi
authors.initials: N
authors.lastname: Sarkar
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India.
authors.forename: Ananya
authors.initials: A
authors.lastname: Pal
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India.
authors.forename: Debraj
authors.initials: D
authors.lastname: Saha
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India.
authors.forename: Manikankana
authors.initials: M
authors.lastname: Bandopadhyay
authors.affiliation: Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India.
authors.forename: Chandrima
authors.initials: C
authors.lastname: Das
authors.affiliation: Department of Gastroenterology, SCB Medical College, Cuttack, India.
authors.forename: Jimmy
authors.initials: J
authors.lastname: Narayan
authors.affiliation: Department of Gastroenterology, SCB Medical College, Cuttack, India.|Kalinga Gastroenterology Foundation, Beam Diagnostics Premises, Cuttack, India.
authors.forename: Shivaram Prasad
authors.initials: SP
authors.lastname: Singh
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India.|National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors.forename: Sekhar
authors.initials: S
authors.lastname: Chakrabarti
authors.affiliation: ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, ICMR Virus Unit, GB 4, 700010, Kolkata, India. runugc@gmail.com.
authors.forename: Runu
authors.initials: R
authors.lastname: Chakravarty
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D015153:Blotting, Western; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D004279:DNA, Viral / Q000187:drug effects; D015536:Down-Regulation; D056945:Hep G2 Cells; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics; D022781:Hepatocytes / Q000187:drug effects* / Q000821:virology; D006657:Histones / Q000187:drug effects; D006801:Humans; D007113:Immunity, Innate; D019259:Lamivudine / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000235:genetics; D018613:Microscopy, Confocal; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D051199:Toll-Like Receptor 7 / Q000819:agonists*; D019562:Viral Load / Q000187:drug effects*; D014779:Virus Replication / Q000187:drug effects*
chemical_list: C557465:1-(2-methylpropyl)-1H-imidazo(4,5-c)quinolin 4-amine; D000998:Antiviral Agents; D004279:DNA, Viral; D006657:Histones; D016328:NF-kappa B; D011804:Quinolines; C495348:TLR7 protein, human; D051199:Toll-Like Receptor 7; D019259:Lamivudine
keywords: Cell-cycle arrest; Epigenetics; Hepatitis B virus; Innate immune response; TLR7