Expression And Correlation Of MTA3, Snail1and E-cadherin In The Liver Of Biliary Atresia

Objective: Although biliary atresia (BA) is the most common infantileobstructive cholangiopathy, its etiology and pathogenesis still remain unclear.Of the possible theories, including hereditary inclination, virus infection,chronic inflammatory or autoimmune-mediated bile duct injury and congenitalmalformation of biliary tract, the key pathogenesis is related to virus infectionand immunoreaction. Despite of surgical intervention with the Kasaiportoenterostomy, the lesion of intrahepatic bile duct is still developed. In theend, biliary cirrhosis occur in most children. Therefore, more than50%children with BA necessite liver transplantion ultimately. Only15%-20%children with BA can survive up to their adulthood, with their chronic liverdisease or cirrhosis. Sclerosing cholangitis in BA has recently been foundclosely related to epithelial-mesenchymal transition (EMT). Moreover, Snailhas played a vital role in the process of EMT. Snail1and Snail2, two highlyrelated members of the Snail superfamily, are direct transcriptional repressorsof E-cadherin and EMT inducers. Metastasis-associated gene3(MTA3) caninhibit the transcription of Snail gene. This study aimed to investigate theexpression and correlation of MTA3, Snail1and E-cadherin gene in the liverof BA and to analyze their roles and significants in the development andprogression of BA.Methods: From February2012to September2013, totally48cases wereenrolled in this study at the department of pediatric surgery in the SecondHospital of Hebei Medical University. Of them,21children with BA were putinto the experimental group, meanwhile17cases with congenital choledochalcyst (CCC) and10cases with hepatic injuries (normal liver, NL) wereclassified into the control groups respectively. The expression of MTA3,Snail1and E-cadherin of the liver biopsies in the three groups were detected and compared by the immunohistochemistry. At the same time, Reversetranscription-polymerase chain reaction (RT-PCR) was applied to measure themRNA expression of MTA3, Snail1and E-cadherin of the liver specimens inthe three groups. All of data were input into SPSS13.0software and werestatistically analyzed. P values <0.05were considered statistically significant.P values <0.01were considered very statistically significant.Results：1Expression of MTA3：Immunohistochemistry was applied to measurethe expression of MTA3of liver tissues in21BA、17CCC and10NL. Thepositive expression rate of MTA3protein were28.57%,82.35%, and90.00%respectively. There were statistically significant differences among them(P<0.01). Furthermore, the expression of MTA3in BA was lower than that inCCC (P<0.01), also lower than that in NL (P<0.01). No significant differencewas found between the expression of MTA3in CCC and that in NL (P>0.05).RT-PCR was applied to measure the expression of MTA3mRNA in the threegroups. The expression of MTA3mRNA were0.10±0.05,0.25±0.10and0.23±0.11respectively and significant difference occurred in them (P<0.01).Furthermore, The expression of MTA3mRNA in BA was lower than that inCCC (P<0.01) and was lower than in NL (P<0.01). No significant differencewas found between the expression of MTA3in CCC and that in NL(P>0.05).2Expression of Snail1：Immunohistochemistry was applied to detect theexpression of Snail1of the liver tissues in21BA,17CCC and10NL. Thepositive expression rate of Snail1protein were66.67%,23.53%and20.00%,there were statistically significant differences among them (P<0.01).Furthermore，the expression of Snail1in BA was higher than that in CCC(P<0.05), also higher than that in NL（P<0.05）. No significant difference wasfound between the expression of Snail1in CCC and that in NL (P>0.05).RT-PCR was applied to measure the expression of Snail1mRNA in the threegroups. The expression of Snail1mRNA were0.09±0.03,0.05±0.03and0.05±0.03respectively and significance difference occurred in them (P<0.01). Furthermore, the expression of Snail1mRNA in BA was higher than that inCCC (P<0.01), and was, higher than in NL (P<0.01).No significantdifference was found between the expression of Snail1in CCC and that in NL(P>0.05).3Expression of E-cadherin：Immunohistochemistry was applied toobserve the expression of E-cadherin of the liver tissues in21BA,17CCCand10NL. The positive expression rate of E-cadherin protein were33.33%,94.12%and90.00%, and statistically significant difference among them(P<0.01). Furthermore，the expression of E-cadherin in BA was lower thanthat in CCC (P<0.01), also lower than that in NL (P<0.01). No significantdifference was found between the expression of E-cadherin in CCC and that inNL (P>0.05). RT-PCR was applied to measure the expression of E-cadherinmRNA in the three groups. The expression of E-cadherin mRNA were0.32±0.16,0.69±0.22and0.75±0.23respectively and significant differenceoccurred in them（P<0.01）. Furthermore,the expression of E-cadherin mRNAin BA was lower than that in CCC (P<0.01), and was higher than in NL(P<0.01). No significant difference was found between the expression ofE-cadherin in CCC and that in NL (P>0.05).4The correlations of three gene mRNA and protein：Both mRNA andprotein, there were negative correlations between MTA3and Snail1expression (r=-0.862, P<0.01; r=-0.671, P<0.05) and between Snail1andE-cadherin (r=-0.715, P<0.01; r=-0.571, P<0.01) expression in BA livertissues. There was a positive correlation between MTA3and E-cadherin in BAliver tissues (r=0.752, P<0.01; r=0.671, P<0.01).Conclusions：The higher expression of Snail1and the lower expressionof MTA3and E-cadherin in BA suggest aforementioned three genes wereclosely correlated with the development of BA. Positive correlations betweenthe expression of MTA3and E-cadherin and negative correlation between theexpression of MTA3and Snail1in liver tissues of BA pointed outdownregulation of MTA3expression was related to EMT in the developmentand progression of BA by promoting Snail1expression and inhibiting E-cadherin expression. The epithelial cell polarity and intercellular adhesionwere destroyed in intrahepatic and outhepatic bile ducts, promoting theprogress of biliary tract inflammation and fibrosis, causing sclerosingcholangitis.