Systems Biology analysis of biological timers and inflammation

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As we get older our immune system tends to get weaker and it becomes increasingly difficult to shake off diseases. At the same time we tend to develop arthritis and other auto-immune diseases which are localised instances of uncontrolled inflammation. In this grant application our multidisciplinary team of scientists consisting of physiologists, biologists, mathematicians and computer scientists aim to look at a very important signalling system NF-kappaB. This system plays an important role in stress and the immune responses and determines the fate of cells in the body, which is essential for general health and wellbeing. We will use a combined experimental and mathematical approach to analyse integrated systems that control NF-kappaB signalling in normal cells and tissues. We found that NF-kappaB carries signal information in the timing of its movements between the nucleus and cytoplasm. The timing of these movements determines which genes are switched on. We now wish to understand how this key process of NFkappaB signalling is controlled through normal life. How is it controlled by the cell division cycle, and how is it controlled by the sleep-wake cycle of the 24 h circadian clock.Recently, we have found that the speed of the oscillations in the NF-kappaB signalling system are very temperature sensitive in the physiological and fever range between 35 and 40 degrees C. This also appears to markedly change the pattern of which genes are switched on or off. Our work so far has been in cell lines grown in the laboratory and we now wish to investigate NF-kappaB signalling in normal cells taken from transgenic mice that have fluorescently labelled NF-kappaB proteins. We will use these cells to determine the NF-kappaB response to temperature, a range of physiological stimuli including glucocorticoids (which are often used in inflammatory treatment), to screen small molecule drugs to find ones that modulate the response and to study the quantitative relationships with the cell cycle and the circadian clock. The data from these experiments and others published in the literature will be used to build integrated mathematical models that can predict important aspects of cell, tissue and animal physiology relevant to understanding the maintenance of a healthy organism and how this may change with age.Key aims will be to understand how the clock and cell cycle together affect the timing and level of NF-kappaB signalling and which target genes are switched on. One of the NF-kappaB family of proteins, p105 encoded by the NFkB1 gene, has been found to cause faster ageing in mice when this gene is missing (Mann and von Ziglnicki, personal communication). We wish to investigate whether changes in NF-kappaB dynamics are involved in this ageing condition. Therefore, we will make a BAC reporter for p105 with fluorescent fusions at either end of the protein.We are an ideal team to perform this work, because we have complementary interdisciplinary skills in cell imaging, image analysis, molecular cell biology, physiology, genomics, bioinformatics and mathematical modelling. A core part of the team has an excellent track record of working together to analyse the NF-kappaB signalling system. In addition, this new project brings in new team members with considerable expertise in animal physiology, circadian clocks and endocrinology.