Project overview
Neutrophil elastase (NE) is an enzyme normally found stored in white blood cells called neutrophils. Neutrophils form part of our immune system and when they detect foreign objects or particles in our blood, such as bacteria for example, they engulf them. Once engulfed within the cell, the bacteria are broken down and killed. It is believed that NE may have a part to play in these processes, but it is not clear. One approach has been to genetically modify mice so that their neutrophils do not make NE, and then investigate how this affects the function of their neutrophils. However the results are conflicting, and any way we do not know the relative contribution of NE to mouse and human immunity. We have therefore decided to adopt a novel approach to determine the biological functions of NE in normal human neutrophils. Our aim is to completely inhibit intracellular NE and test what effect this has on the ability of the neutrophils to move and engulf and kill bacteria. Our plan is to synthesise large spherical polymer molecules called dendrimers that we have noticed are engulfed by neutrophils. We will attach some of the best small molecule inhibitors of NE onto the surface of our dendrimers so that when they are engulfed by the neutrophils the NE inside the neutrophils will be inhibited. We will then test the neutrophils to see if they are able to perform their normal tasks or whether our drug-coated dendrimers have disabled the whole cell. We will perform our tests on blood samples taken from healthy human volunteers. The research will happen in a number of phases, first we must synthesise the dendrimers, then we must select suitable existing NE-inhibiting drugs and work out how best to attach them to the dendrimers. We will have to make sure that the dendrimers are still engulfed by neutrophils even after coating them with drugs and that the whole dendrimer-drug molecule is soluble in blood. When new dendrimer-drug molecules are made they will be put through a series of biological tests. Firstly to see which cells in the blood take them up, secondly to see if intracellular NE is inhibited in neutrophils, and finally to see what effect this has on neutrophil function. If we need to make changes to the dendrimer and/or drug we will do this then synthesise some new molecules and test them again. Most of our time will be spent in this research cycle of development and testing. If our research is successful we will have learned some very important facts about the role of NE in neutrophils and also our ability to control the levels of NE in our bodies. It might then be possible that our drug-coated dendrimers could be developed into new drugs themselves and used to treat diseases where NE is a problem or as an emergency treatment in some cases of chemical poisoning.