title: [Hepatitis B virus X protein upregulates the expression of CD59 and Crry in mouse podocytes].
abstract: OBJECTIVE
  Different from primary membranous nephropathy, hepatitis B virus associated membranous nephropathy (HBV-MN) shows lower deposits of membrane attack complex (C5b-9) in glomerular subepithelium. The causes of relatively low complement activation in this disease remain unclear. The aim of this study was to investigate the influence of hepatitis B x protein (HBx) on the expression of CD59 and Crry in mouse podocytes.
  
  
  METHODS
  Cultured mouse podocytes were divided into adenovirus vector hepatitis B virus X gene (Ad-HBx) transfected group (Ad-X group), blank podocytes group (B group) and adenovirus vector transfected group (Ad group). CD59 and Crry mRNA expression were assayed by semiquantitative RT-PCR. CD59 and Crry expression were tested by flow cytometry. The effect of HBx on complement activation was evaluated with MTT method. And then, the effects of P38MAPK, PI-3K and ERK1/2 pathway inhibitors (SB203580, LY294002, U0126) and DMSO on CD59 and Crry expression were respectively detected by flow cytometry.
  
  
  RESULTS
  Proteins CD59 and Crry expression rates (%) in group B, Ad group and Ad-X group were 17.71 ± 3.81, 18.29 ± 3.36 and 45.7 ± 9.01; 18 ± 2.31, 21.78 ± 2.01 and 47.45 ± 9.95, respectively. Compared with group B, CD59 and Crry expression in group Ad was not significantly different (P values for both > 0.05), but CD59 and Crry protein expression in Ad-X group was significantly higher than that in groups B and Ad (P values for both < 0.005); CD59 and Crry gene expression in group Ad was not significantly different from that in group B (P values for both > 0.05). However, CD59 and Crry gene expression of Ad-X group was significantly higher than that in groups B and Ad (P values for both < 0.05). Flow cytometry detected CD59 protein expression rates (%) were 17.35 ± 1.24, 46.19 ± 9.77, 43.03 ± 6.83 and 40.04 ± 6.39 and Crry protein expression rates (%) were 18.14 ± 3.56, 31.95 ± 1.68, 31.95 ± 1.69 and 37.14 ± 3.92 after SB203580, LY294002, U0126 and DMSO were added to Ad-X group respectively. P38 pathway inhibition resulted in significantly lower CD59 and Crry expression than Ad-X group (P values for all < 0.005), but PI-3K, ERK1/2 pathway inhibitors and DMSO had no significant effect on the expression of CD59 and Crry (P values for all > 0.05). The inhibition rates of cell lysis were significantly higher in Ad-X group than in groups B and Ad at each serum dilution point (P values for all < 0.05), while groups B and Ad had no significant difference in cell viability.
  
  
  CONCLUSIONS
  HBx can up-regulate CD59 and Crry expression in podocytes through activating P38 pathway, resulting in decreased complement activation, which may facilitate latent HBV infection in podocytes and play a role in development of hepatitis B virus associated glomerulonephritis (HBV-GN).
authors.affiliation: Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Xiao-ling
authors.initials: XL
authors.lastname: Yin
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Zhou
mesh_terms: D000818:Animals; D018957:CD59 Antigens / Q000378:metabolism*; D002478:Cells, Cultured; D051379:Mice; D050199:Podocytes / Q000276:immunology / Q000378:metabolism*; D011951:Receptors, Complement / Q000378:metabolism*; D017463:Receptors, Complement 3b; D015534:Trans-Activators / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D018957:CD59 Antigens; C081470:Cr1l protein, mouse; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D048051:p38 Mitogen-Activated Protein Kinases