JOINT EPSRC/MRC CHEMICAL BIOLOGY Pharmacological targeting of cytosolic calpain-1: The development of novel inhibitors

白色血细胞，如中性粒细胞和淋巴细胞通过离开血液循环进入组织并破坏感染微生物来对抗感染。然而，有一些炎症性疾病，其中这些细胞是问题的原因。例如，在类风湿性关节炎中，白色细胞不断地离开血流并迁移到受影响的关节，在那里它们被不适当地激活，以？攻击？关节的组织这会导致关节的逐渐破坏。 毫不奇怪，在试图了解白色细胞离开血流的机制方面已经做出了相当大的努力，以便设计有效的治疗方法来阻止这种情况。成功之一是使用单克隆抗体来阻断分子信号。打电话？使白色细胞离开血流。然而，这种方法存在问题。首先，治疗涉及昂贵的抗体输注，必须在医院进行。其次，抗体具有高度选择性，只能识别并阻断一组分子。因为可能有一系列的分子？打电话吗对于白色细胞，任何单一的单克隆抗体都可能无效。因此，我们研究了白色细胞如何离开血流的机制，因为这一定是一个共同的事件，而不管确切地涉及哪种召唤分子。我们已经发现细胞改变形状以穿过血管壁。这涉及细胞表面积的明显大幅增加。我们有证据表明，这是因为细胞膜最初非常褶皱。当一种叫做钙蛋白酶-1的酶破坏了将皱纹连接在一起的蛋白质连接时，这些皱纹就会展开。如果这种酶被抑制，展开就会停止，白色细胞离开血液的速度就会大大降低。这将是一种抗炎药物的基础，这种药物可以简单地口服。幸运的是，我们已经知道了一些抑制这种酶的合成分子。此外，我们知道它们与酶结合的位置。在这个项目中，我们计划利用这些知识？裁缝？这个分子家族变得更有效，只对钙蛋白酶-1有选择性。这将通过抑制也切割蛋白质的其他酶来最小化不必要的副作用的可能性。

White blood cells, such as neutrophils and lymphocytes combat infection by leaving the blood circulation to enter the tissues and destroy infecting microbes. However, there are a number of inflammatory disease in which these cells are the cause of the problem. In rheumatoid arthritis, for example, white cells continually leave the blood stream and migrate to the affected joints, where they are inappropriately activated to ?attack? the tissues of the joint. This causes a progressive destruction of the joint. Unsurprisingly, considerable effort has been made in trying to understand the mechanism by which white cells leave the blood stream so that effective treatments can be devised to stop this. One of the successes has been the use of monoclonal antibodies to block the molecular signals which ?call? white cells to leave the blood stream. However there are problems, with this approach. Firstly, the treatment involves a costly infusion of antibody which must be done in hospital. Secondly, antibodies are highly selectively and can only recognise, and so block, one set of molecules. Since there may be a range of molecules ?calling? to the white cells, any single monoclonal antibody may fail to be effective. We have therefore looked at the mechanics of how the white cells leave the blood stream, because this must be a common event regardless of precisely which calling molecules are involved. We have found that the cells change shape in order to slip through the blood vessel walls. This involves an apparent large increase in the surface area of the cells. We have evidence that this occurs because the membrane of the cells is initially very wrinkled. These wrinkles unfurl when the protein links which hold them together are broken by an enzyme called calpain-1. If this enzyme is inhibited, the unfurling stops and the speed which white cells can leave the blood is greatly reduced. This would be the basis for an anti-inflammatory drug which could be simply taken by mouth. Luckily, we already know of some synthetic molecules which inhibit the enzyme. Furthermore, we know where they bind to the enzyme. In this project, we plan to use this knowledge to ?tailor? this family of molecules to become more potent and selective only for calpain-1. This will minimise the possibility of unwanted side effects by inhibition of other enzymes which also cut proteins.