Functional Mx Protein Does Not Prevent Experimental Biliary Atresia in Balb/c Mice

Abstract

Biliary atresia (BA) is a rare cholestatic disease, which manifests itself in the form of inflammation of the liver and bile ducts in newborns, with an unknown etiology and a poor outcome. Mx proteins, which are mediators of innate, antiviral resistance induced by type I interferon, were recently detected in the livers of children with BA. Therefore, the aim of this study was to examine whether the expression of Mx protein could affect the course of experimental BA in mice. A total of 185 newborn Balb/c mice (expressing dysfunctional Mx protein) and Balb/c-Mx+-A2G mice (with functional Mx protein) were intraperitoneally infected with rhesus rotavirus (RRV) or injected with saline solution as controls. They were sacrificed if they showed signs of cholestasis or at three weeks after infection. The expression of hepatic Mx protein was detected by immunostaining (POX) and the hepatic virus load was determined. There was no significant difference in the incidence of cholestasis between wild-type Balb/c mice and Balb/c-Mx+-A2G mice (67 % vs. 65 %). However, Mx protein was highly expressed in Balb/c-Mx+-A2G mice with BA phenotype, but not in wild type Balb/c mice or disease-free Balb/c-Mx+-A2G mice despite RRV infection. The difference in the hepatic virus load was not statistically significant in mice with BA. In conclusion, Mx protein does not prevent newborn Balb/c mice from developing biliary atresia after RRV infection. However, the expression of Mx protein is independent of the hepatic virus load and could be used as a marker of BA in humans, as well as in the RRV model.

Key words

biliary atresia - Mx protein - rhesus rotavirus - murine model

References

• 1 Al-Masri A N, Flemming P, Leonhardt J, Rodeck B, Petersen C. Expression of the IFN-induced Mx proteins in biliary atresia.  J Pediatr Surg. 2006;  41 1139-1143
• 2 Batusic D S, Armbrust T, Saile B, Ramadori G. Induction of Mx-2 in rat liver by toxic injury.  J Hepatol. 2004;  40 446-453
• 3 Czech-Schmidt G, Verhagen W, Szavay P, Leonhardt J, Petersen C. Immunological gap in the infectious animal model for biliary atresia.  J Surg Res. 2001;  101 62-67
• 4 Haller O, Stertz S, Kochs G. The Mx GTPase family of interferon-induced antiviral proteins.  Microbes Infect. 2007;  9 1636-1643
• 5 Halminen M, Ilonen J, Julkunen I, Ruuskanen O, Simell O, Mäkelä M J. Expression of MxA protein in blood lymphocytes discriminates between viral and bacterial infections in febrile children.  Ped Research. 1997;  41 647-650
• 6 Harada K, Sato Y, Itatsu K, Isse K, Ikeda H, Yasoshima M, Zen Y, Matsui A, Nakanuma Y. Innate immune response to double-stranded RNA in biliary epithelial cells is associated with the pathogenesis of biliary atresia.  Hepatology. 2007;  46 1146-1154
• 7 Huang Y H, Chou M H, Du Y Y, Huang C C, Wu C L, Chen C L, Chuang J H. Expression of Toll-like receptors and type 1 interferon specific protein MxA in biliary atresia.  Lab Invest. 2007;  87 66-74
• 8 Kuebler J F, Czech-Schmidt G, Leonhardt J, Ure B M, Petersen C. Type-I but not type-II interferon receptor knockout mice are susceptible to biliary atresia.  Pediatr Res. 2006;  59 790-794
• 9 Leifeld L, Ramakers J, Schneiders A M, Dumoulin F L, Sterneck M, Muller A, Sauerbruch T, Spengler U. Intrahepatic MxA expression is correlated with interferon-alpha expression in chronic and fulminant hepatitis.  J Pathol. 2001;  194 478-483
• 10 Mack C L, Tucker R M, Sokol R J, Karrer F M, Kotzin B L, Whitington P F, Miller S D. Biliary atresia is associated with CD4+Th1 cell-mediated portal tract inflammation.  Pediatr Res. 2004;  56 79-87
• 11 Petersen C, Bruns E, Kuske M, v. Wussow P. Treatment of extrahepatic biliary atresia with interferon-α in a murine infectious model.  Pediatr Res. 1997;  42 623-628
• 12 Petersen C, Kuske M, Bruns E, Biermanns D, Wussow P V, Mildenberger H. Progress in developing animal models for biliary atresia.  Eur J Pediatr Surg. 1998;  8 137-141
• 13 Petersen C. Pathogenesis and treatment opportunities for biliary atresia.  Clin Liver Dis. 2006;  10 73-88
• 14 Rauschenfels S, Krasmann M, Verhagen W, v. Wasielewski R, Al-Masri A N, Melter M, Leonhardt J, Kuebler J F, Petersen C. Incidence of hepatotropic viruses in biliary atresia.  Eur J Pediatr. 2008; 
• 15 Sokol R J, Mack C, Narkewicz M R, Karrer F M. Pathogenesis and outcome of biliary atresia: current concepts.  J Pediatr Gastroenterol Nutr. 2003;  37 4-21
• 16 Staeheli P, Pitossi F, Pavlovic J. Mx proteins: GTPases with antiviral activity.  Trends Cell Biol. 1993;  8 268-272
• 17 Szavay P O, Leonhardt J, Czech-Schmidt G, Petersen C. The role of reovirus type 3 infection in an established murine model for biliary atresia.  Eur J Pediatr Surg. 2002;  12 248-250