Core support for collaborative glycomic and proteomic research

Most of us have heard about DNA, how it is the basic template of life, and how it codes for molecules called Proteins which carry out many of the fundamental tasks both in and between the billions of cells which make up a living organism as complex as a human being. When things go wrong with the two key sets of molecules, either the DNA or the Proteins produced from it, then the living being can rapidly experience a deterioration of function which we classify as a disease state. Much of modern biological research is targeted at understanding how things can go wrong at the molecular level, and how we might correct them and thus make significant contributions to human health. But to say that there are just two key types of molecules in living systems is an over-simplification: there are others, and our Group at Imperial believes that the molecules commonly called Sugars or Carbohydrates deserve special attention because of the major potential role they can and do have in the way that molecules and cells recognise each other and therefore the interactions they have in the promotion of health or disease in the body as a whole. Every cell in our body is coated with a sugar-rich layer called the glycocalyx. Acting as 'identity tags', chains of sugars called glycans on the periphery of the glycocalyx interact with a whole variety of receptors (recognition molecules) and thereby help to control the social (correct) and anti-social (errant) behaviour of cells. The Imperial laboratory specialises in the development and exploitation of high sensitivity screening and structural techniques involving advanced mass spectrometric instrumentation for characterising the detailed structure of important glycans and thus providing a better understanding of how these interactions take place and how we might intervene at the molecular level when things go wrong. There are now numerous examples of fascinating glycan-mediated biological phenomena which demand our further understanding: How does a parasite camouflage itself against its host immune system? Why are developing foetuses not detected and rejected as 'foreign' by their mothers? How do defensive white blood cells circulating in the bloodstream know when to enter diseased tissues to fight infection? We, and others, believe that these and related questions about biological recognition, will be solved when we fully understand how glycans on cell surfaces engage with glycan-binding proteins to mediate adhesive and signalling events. Let us take a philosophical look at just one of the above examples which relates to our understanding of immunology, which as a discipline is a key area of research on this grant. The example of a pregnant woman above represents a very significant immunological puzzle. We know that our organs carry specific types of immune markers and, unless these markers match, transplanted organs will be rejected. In the case of normal pregnancy, half of the immune markers associated with the foetus will come from the father and are usually foreign to the mother. However, we also know that women can become surrogate mothers by using in vitro fertilisation techniques. In the case of surrogate pregnancy, none of these immune markers may match. Therefore the central question is why does the mother not reject her foetus? It is now evident that the mother sets up an 'immunosuppressive shield' that blocks her own immune response so that the foetus is not rejected. However the molecular interactions mediating this 'shielding' are not understood. Our hypothesis is that the sugar coats of cells and of proteins in body fluids play a vital recognition role in immune suppression, and part of our current grant proposal seeks to acquire the experimental evidence to address this hypothesis, thereby opening up potential new avenues for dealing with infection.