Serrano-Mendioroz Irantzu, Sampedro Ana, Mora María Isabel, Mauleón Itsaso, Segura Victor, Enríquez de Salamanca Rafael, Harper Pauline, Sardh Eliane, Corrales Fernando José, Fontanellas Antonio
Hepatology Area, Centre for Applied Medical Research, University of Navarra, Spain.
Hepatology Area, Centre for Applied Medical Research, University of Navarra, Spain; Proteomics and Bioinformatics Laboratory, CIMA, University of Navarra, ProteoRed-ISCIII, Spain.
J Proteomics. 2015 Sep 8;127(Pt B):377-85. doi: 10.1016/j.jprot.2015.05.004. Epub 2015 May 13.
Acute intermittent porphyria (AIP) is an autosomal dominant metabolic disorder caused by a deficiency of hepatic porphobilinogen deaminase (PBGD). The disease is characterized by life threatening acute neurovisceral attacks. The aim of this study was to identify metabolites secreted by the hepatocytes that reflect differential metabolic status in the liver and that may predict response to the acute attack treatment. Plasma vitamin D binding protein (VDBP) from a mouse model of AIP displayed an abnormal migration in 2D-electrophoresis that is efficiently recovered upon gene therapy leading to liver specific over-expression of the PBGD protein. The change in VDBP mobility results from a differential isoelectric point suggesting a post-translational modification that takes place preferably in the liver. Liquid chromatography-mass spectrometry (LC-MS) analysis of human samples before and after glycosidase treatment revealed glycosylated plasma VDBP specifically in patients with recurrent attacks of AIP. Glycosylated VDBP recovered normal values in three severely afflicted AIP patients submitted to therapeutic liver transplantation. Our findings suggest that post-translational modification of VDBP might be considered as a promising biomarker to study and monitor the liver metabolic status in patients with AIP.
We describe an increased glycosylation of VDBP in porphyric livers. Normal glycosylation was recovered upon liver gene therapy in a mouse model of porphyria or after liver transplantation in severely afflicted patients with AIP. Moreover, quantification of glycosylated VDBP by our ELISA immunoassay or LC-MS protocol in patients undergoing PBGD-gene therapy (www.aipgene.org) may be used as a marker indicating improvement or normalization of the patient's hepatic metabolism. This article is part of a Special Issue entitled: HUPO 2014.
急性间歇性卟啉病（AIP）是一种常染色体显性代谢紊乱疾病，由肝脏卟胆原脱氨酶（PBGD）缺乏引起。该疾病的特征是危及生命的急性神经内脏发作。本研究的目的是鉴定肝细胞分泌的代谢物，这些代谢物反映肝脏中不同的代谢状态，并可能预测对急性发作治疗的反应。来自AIP小鼠模型的血浆维生素D结合蛋白（VDBP）在二维电泳中显示出异常迁移，基因治疗导致PBGD蛋白在肝脏中特异性过表达后，这种异常迁移可有效恢复。VDBP迁移率的变化是由不同的等电点引起的，这表明翻译后修饰主要发生在肝脏中。糖苷酶处理前后人类样本的液相色谱 - 质谱（LC - MS）分析显示，AIP复发患者血浆中存在糖基化的VDBP。在接受治疗性肝移植的三名严重AIP患者中，糖基化VDBP恢复到正常水平。我们的研究结果表明，VDBP的翻译后修饰可能被视为研究和监测AIP患者肝脏代谢状态的一种有前景的生物标志物。
我们描述了卟啉病肝脏中VDBP糖基化增加。在卟啉病小鼠模型中进行肝脏基因治疗后，或在严重AIP患者进行肝移植后，糖基化恢复正常。此外，通过我们的ELISA免疫测定法或LC - MS方法对接受PBGD基因治疗（www.aipgene.org）患者的糖基化VDBP进行定量，可作为指示患者肝脏代谢改善或正常化的标志物。本文是名为：HUPO 2014的特刊的一部分。
