Regulation of Pulmonary Neutrophils In Vivo: Direct Interrogation by Intravital Microscopy

Neutrophils are the most numerous white blood cells in the blood. They are critical in fighting disease causing microbes (bacteria, etc.). The blood vessels of the lung are extensive, very narrow and uniquely composed in order to allow the oxygen necessary for us to live into the blood and the carbon dioxide generated by our muscles and other organs to escape. When we breathe, microbes can come into close contact with the cells of the lung, therefore white blood cell function is critical in protecting the lung from infection. However, a lot of the processes that make neutrophils so good at fighting disease can be dangerous if not properly controlled. Neutrophils have been implicated in several 'inflammatory' lung diseases including acute respiratory distress syndrome caused by lung infections or injury, and severe asthma.
The way that neutrophils act can be regulated by several factors. Blood cells are produced in the bone marrow, and what stimulates their release into the blood can have marked effects on their function. Additionally, the cells that line blood vessels and the other white blood cells encountered can affect neutrophil function. New microscope technology allows us for the first time to look at white blood function in real lung blood vessels. This proposal investigates how neutrophils are regulated by building and combining new technologies to allow us to directly observe neutrophils in lung blood vessels and using these techniques to better understand the behaviour of neutrophils in healthy and diseased lungs.
The study aims to uncover fundamental aspects of neutrophil function, both beneficial in defence against microbes, and dangerous in terms of lung disease.

Neutrophils are critical early mediators of inflammation involved in protective immunity to pathogens and implicated in the pathology of several lung diseases including acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD) and severe asthma. The microvasculature of the lung is unique in terms of how extensive and small the capillaries are and in particular with respect to their proximity to an external mucosa. The vascular endothelium in alveolar capillaries shares a basement membrane with the epithelium to facilitate gas transport. As such, tissue cells and cells within the capillaries are potentially under assault from the external environment. An understanding of the molecular mechanisms underlying inflammation in the lung is critical, since inflammation left unchecked compromises lung function.
This project develops and uses cutting-edge imaging techniques to directly interrogate how neutrophils are regulated in the lung microvasculature in situ to test the hypothesis that: Neutrophil regulation in lung homeostasis and inflammation is dependent upon bone marrow release, the lung microenvironment and their interaction with other leukocytes in pulmonary capillaries. Experiments will directly address these important influences in their physiological context.

The findings of this study with make impact at several different levels:
Basic understanding of leukocyte function is critical to be able to build on to understand the pathogenesis of lung disease. These studies will provide fundamental understanding of how neutrophils are regulated in the blood vessels of the lung. This award will allow me to break new ground and provide the foundation of my own research programme, future publications and grant applications. This will be of great benefit my own future work to address more complicated disease pathogenesis, and also that of others in terms of generation of new knowledge and also the training of new scientists.
Intravital microscopy of leukocytes in the mouse lung is still a cutting-edge technology. To my knowledge, mine is the only UK lab where it is currently established. Its continued development and use to address the hypotheses here is a clear example of the development and utilisation of new and innovative methodologies, equipment, techniques and technologies. These skills will be shared with other researchers nationally and internationally. It will directly benefit students and post-doctoral trainees coming to the lab giving providing them with training in technology that has a great deal of potential across a number of disciplines.
Neutrophils have been implicated in the pathology of several serious and debilitating lung diseases, fundamental understanding of how neutrophils contribute to these diseases addresses globally important sources of mortality and morbidity.
I will also use the findings of the research to continue to contribute to increasing public awareness and understanding of science by taking part or continuing to take part in the Imperial Festival public engagement forum, the Pint of Science festival and continuing to co-organise Imperial CREST academy.