Bernuau D, Legrès L, Lamri Y, Giuily N, Fey G, Feldmann G
Laboratoire de Biologie Cellulaire, INSERM U24, Faculté de Médecine Xavier-Bichat, Paris, France.
J Exp Med. 1989 Jul 1;170(1):349-54. doi: 10.1084/jem.170.1.349.
Functional heterogeneity in the lobule with regard to plasma protein synthesis is still debated. Therefore, we have localized in liver sections from normal rats and from rats with turpentine-induced AIR the mRNA and protein products of three genes with different alterations in their hepatic expression during an AIR: alpha 2M and alpha 1PI, two positively reacting acute-phase genes, and alpha 1I3, a negative acute-phase reactant. In normal liver, all hepatocytes expressed alpha 2M and alpha 1I3 mRNA, but a preferential expression of alpha 2M and alpha 1I3 mRNA and protein in the PP and ML zones was observed. During an AIR, the level of alpha 2M mRNA increased fourfold in the cytoplasm of PP and ML hepatocytes, while the level of cytoplasmic alpha 1I3 mRNA was decreased about fourfold in the same zones, with parallel variations in the expression of the corresponding proteins. In contrast, no significant modulation of the RNA and protein concentrations of both genes was detected in PV areas. alpha 1PI mRNA was expressed at the same levels in the three lobular zones in normal liver, but staining for the alpha 1PI protein was more intense in the PV zones. During the acute-phase response alpha 1PI mRNA levels were increased twofold in all three lobular zones, and alpha 1PI staining became homogeneous within the lobule. These results demonstrate that the location of a hepatocyte with the liver lobule can influence the expression of the three genes under study both at pre- and post-translational levels, in basal conditions, as well as during modulation of their expression during the inflammatory reaction.
关于小叶中血浆蛋白合成的功能异质性仍存在争议。因此，我们在正常大鼠和松节油诱导的急性炎症反应（AIR）大鼠的肝脏切片中，定位了三个基因的mRNA和蛋白质产物，这三个基因在急性炎症反应期间肝脏表达有不同变化：α2M和α1PI，两个呈阳性反应的急性期基因，以及α1I3，一个阴性急性期反应物。在正常肝脏中，所有肝细胞均表达α2M和α1I3 mRNA，但在门静脉周围（PP）和中间带（ML）区域观察到α2M和α1I3 mRNA及蛋白质的优先表达。在急性炎症反应期间，PP和ML区肝细胞胞质中α2M mRNA水平增加了四倍，而同一区域胞质α1I3 mRNA水平下降了约四倍，相应蛋白质的表达也有平行变化。相比之下，在汇管区（PV）未检测到这两个基因的RNA和蛋白质浓度有明显调节。正常肝脏中，α1PI mRNA在三个小叶区域的表达水平相同，但α1PI蛋白染色在PV区更强。在急性期反应期间，所有三个小叶区域的α1PI mRNA水平均增加了两倍，并且α1PI染色在小叶内变得均匀。这些结果表明，肝细胞在肝小叶中的位置可在基础条件下以及炎症反应期间基因表达调节过程中，在翻译前和翻译后水平影响所研究的三个基因的表达。
