Molecular pathobiological studies on the multi-functional SERPIN, protein C inhibitor-dependent diseases

蛋白C抑制物(PCI)是SERPIN家族的成员之一，在人体的各种组织中都有产生，包括肝脏、肾脏和睾丸。除了抑制抗凝蛋白C途径外，经皮冠状动脉介入治疗还抑制尿液uPA，这是一种众所周知的肿瘤细胞侵袭的介质。(1)比较了人肾细胞癌(RCC)组织和非肿瘤肾组织中PCI1的表达，探讨了PCI1在肾组织中的生物学意义。PCImRNA在正常肾小管上皮细胞中有表达，但在肾癌和肾癌细胞系(Caki-1细胞)中未见表达。在肾癌细胞系中发现了pCI基因启动子区域的部分CpG岛甲基化，而在非肿瘤肾细胞中未检测到甲基化。与对照组相比，转导pCI表达载体的Caki-1细胞的体外侵袭力显著降低。这些都是…更多的研究表明，PCI通过抑制肾癌细胞分泌uPA而调节其侵袭潜能。(2)建立了人pCI基因转基因(TG)小鼠，并对其表达的pCI基因的组织分布和生物学功能进行了研究。Northern印迹和免疫组织化学分析表明，在TG小鼠中，人的pCI不仅在睾丸、卵巢和子宫等生殖器官中表达，而且在肝、肝、肾上皮细胞、心脏和脑中也有表达，这些pCI的组织分布与人类相似。在TG小鼠中表达的pCI通过与人活化蛋白C(APC)形成复合物，有效地抑制了体外注射的APC在TG小鼠体内的抗凝和抗炎活性。这些结果表明，人pCI基因TG小鼠可作为评价人pCI的病理意义和体内治疗效果的实验动物模型。较少

Protein C inhibitor (PCI), a member of the SERPIN family, is produced in various human tissues, including the liver, kidney, and testis. In addition to inhibit the anticoagulant protein C pathway, PCI also inhibits urinary uPA, which is a well-known mediator of tumor cell invasion. (1) To clarify the biological significance of PCI in the kidney, we compared the expression of PCI between human renal cell carcinoma (RCC) tissue and non-tumor kidney tissue. The PCI level in RCC tissue was found to be significantly lower than in non-tumor kidney tissue, and expression of PCI mRNA was detected in normal renal proximal tubular epithelial cells, but not in RCC nor in an RCC cell line (Caki-1cells). Methylation of some CpG islands in the promoter region of PCI gene was detected from RCC cell lines, but not from non-tumor kidney cells. The in vitro invasiveness of Caki-1 cells transfected with a PCI expression vector was significantly decreased compared to mock-transfected Caki-1 cells. These f … More indings suggest that PCI regulates the invasive potential of RCC cells by inhibiting uPA secreted by these cells. (2) Moreover, we produced human PCI gene-transgenic (TG) mice and characterized the tissue distribution and biological functions of PCI expressed in the TG mice. Northern blot and immunohistochemical analyses showed that in the TG mice the human PCI is expressed not only in the reproductive organs such as testis, ovary and uterus, but also in the liver hepatocytes, renal epithelial cells, heart and brain; these tissue distribution of the PCI being similar to that in humans. The PCI expressed in the TG mice efficiently inhibited the anticoagulant and anti-inflammatory activities of the extraneously injected human activated protein C (APC) in the TG mice by forming a complex with APC. These findings demonstrate that human PCI gene TG mice are useful as experimental animal models to evaluate pathological significance of human PCI and also therapeutic effects of human APC in vivo. Less