title: Differential expression of transforming growth factor-β1 and HBx enhances hepatitis B virus replication and augments host immune cytokines and chemokines.
abstract: OBJECTIVE
  This study investigated how HBV replication and host immune response are effected by reduced expression of TGF-β1 and HBx.
  
  
  METHODS
  Short interfering RNA (siRNA) knockdown technology has been used to examine the role of TGF-β1 in hepatitis B virus replication. The siTGF-β1 has been transfected along with 1.3mer HBV x-null to investigate the knockdown effect of TGF-β1 on HBV replication and host immune factors.
  
  
  RESULTS
  In this study, we found that diminished expression of TGF-β1 and increased expression of HBx enhances HBV replication several folds. The differential expression of TGF-β1 and HBx also stimulated transcriptional viral replicative intermediate (pgRNA) and secretion of core and 'e' antigen at translational level. Consequently, several cytokines such as IL-2, IL-8 and chemokine monocyte- chemoattractant protein (MCP-1) were increased significantly in response to stimulation of HBV replication. In contrast, TNF-α and RANTES mRNA expression increased insignificantly in response to enhanced HBV replication.
  
  
  CONCLUSIONS
  We concluded that reduced expression of TGF-β1 together with HBx expression stimulate HBV replication and immune response, although the underlying mechanism of stimulation most likely differs.
authors.affiliation: Department of Botany and Microbiology College of Science, King Saud University, Riyadh, Saudi Arabia. majhdi@ksu.edu.sa
authors.forename: Fahad N
authors.initials: FN
authors.lastname: Almajhdi
authors.forename: Ahmed Y
authors.initials: AY
authors.lastname: Al-Qudari
authors.forename: Zahid
authors.initials: Z
authors.lastname: Hussain
mesh_terms: D018925:Chemokines / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D056945:Hep G2 Cells; D006512:Hepatitis B Core Antigens / Q000378:metabolism; D006513:Hepatitis B e Antigens / Q000378:metabolism; D006515:Hepatitis B virus / Q000235:genetics / Q000254:growth & development* / Q000276:immunology / Q000378:metabolism; D022781:Hepatocytes / Q000276:immunology / Q000821:virology*; D006801:Humans; D012313:RNA / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins; D014779:Virus Replication
chemical_list: D018925:Chemokines; D016207:Cytokines; D006512:Hepatitis B Core Antigens; D006513:Hepatitis B e Antigens; D012333:RNA, Messenger; C508960:TGFB1 protein, human; D015534:Trans-Activators; D053773:Transforming Growth Factor beta1; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; C100808:pgRNA; D012313:RNA