Development of a novel therapeutic approach to the renal injury by the control of anaphylatoxins.

在本研究中，我们探讨了精氨酸特异性羧肽酶（CPR）作为体内有效抗萘曲霉毒素剂的可能性。众所周知，CPR通过去除精氨酸残留物来消除过敏毒素如C5 a。为了验证这一假设，我们首先克隆了人羧肽酶原R（pro-CPR）的大鼠同源物。通过尾静脉逆行注射人促红细胞生成素（EPO）基因，评价体内转基因技术的有效性和可靠性。通过该方法将EPO基因有效地导入肝细胞中。然后，我们使用pro-CPR基因的大鼠同源物，以增加血浆中pro-CPR的浓度。我们发现血浆pro-CPR浓度增加了2至4倍。然后，我们诱导过敏毒素依赖性疾病的大鼠。用少量LPS和抗肾小球基底膜抗体（anti-GBM）处理的大鼠表现出以血栓性肾小球毛细血管炎症为特征的非常严重的肾小球损伤。当未用抗C5 a受体拮抗剂或血栓调节素治疗时，大鼠在诱发疾病后24小时内死亡。pro-CPR基因转移对这些大鼠的影响有限。这些结果表明，需要进一步的研究，例如，通过基因转移的活性形式的CPR。

In the present study, we investigated the possibility that arginine specific carboxypeptidase (CPR) is used as the effective anti-naphylatoxin agent in vivo. It is well known that CPR inactivate anaphylatoxins such as C5a by removing the argine residue. In order to test this hypothesis, we first cloned the rat homolog of human pro-carboxypeptidase R (pro-CPR). We then evaluated the efficacy and the reliability of in vivo gene transfer technique by retrograde injection of human erythropoietin (EPO) gene via tail vein. The EPO gene was efficiently introduced into the liver cells by this method. Then, we used rat homolog of pro-CPR gene in order to increase the concentration of pro-CPR in plasma. We found that 2 to 4 folds increase of plasma pro-CPR concentration was achieved. Then we induced anaphylatoxin-dependent diseases in rats. Rats treated with small amount of LPS and anti-glomerular basement membrane antibody (anti-GBM) showed very severe glomerular lesions characterized by the thrombotic glomerular capillary inflammation. Rats died within 24 hours after induction of diseases when they are not treated with anti-C5a receptor antagonists or thrombomodulin. The effects of pro-CPR gene transfer to these rats were limited. These results suggest that the further study is needed, for example, by the gene transfer of active form of CPR.