Chemokines and the regulation of matrix metalloproteinase activity in pulmonary tuberculosis.

Tuberculosis (Tb) causes over two million deaths every year world wide. One in 3 people in the entire world carry the bug in their system. Currently tablet treatment is prolonged and difficult to remember to take. Rising drug resistance rates by the bugs causing infection to current antibiotics is making treatment even more difficult. New approaches to therapy are required.
We wish to investigate the theory that overproduction of certain bodily proteins occurs in tuberculosis. Normally these proteins, called matrix metalloproteinases, are used to help fight the infection but in excess they cause destruction of any tissue infected by Tb resulting in permanent scarring or even death of the patient. We shall study this in a laboratory system using human lung cells. We shall focus on the local hormones (chemokines) which control these proteins and work to understand how they do this. Next, we shall look in samples from Tb patients to see if the ideas are confirmed in real disease. A fuller understanding of the train of events in Tb means we may be able to identify targets for developing new treatments that ensure better outcome for patients.

Tuberculosis (Tb) is a worldwide problem causing over 2 million deaths a year and the emergence of drug resistant strains (most recently XTB which is resistant to isoniazid, rifampicin and 3 second line drugs) is a serious threat with few new therapies available. Tb is increasingly common in the UK. Recruitment of immune cells to sites of Tb infection and their activation leads to tissue damage, morbidity and mortality. Matrix Metalloproteinases (MMPs) are enzymes which are immunomodulatory and cause direct tissue damage. Chemokines are small molecules secreted by immune and non-immune cells which recruit and activate immune cells. There is good evidence from JSF‘s and other groups that chemokines and MMPs have key roles in the immunopathology of TB. MMPs are known to regulate chemokines by cleaving them or their precursors to activate or inhibit their function. Evidence emerging that chemokines may also regulate MMP activity but little is known about this process in infection and there are no published data in Tb. The project hypothesis is that chemokines regulate MMP secretion and the development of a matrix degrading phenotype in Tb; it is based on good pilot data. Specific aims are to investigate:
kinetics and magnitude of MMP 1,3, 7 and 9 (shown to be key in Tb) and TIMP (Tissue inhibitor of metalloproteinase) gene expression and secretion in respiratory epithelial cells and fibroblasts.
the role of mitogen activated protein kinases and transcriptional control (eg by AP-1 and NF B) in regulation of chemokine-dependent MMP gene expression.
clinical correlates of chemokine, MMP and TIMP co-secretion in patients with pulmonary Tb.
In order to address these aims, the project will provide research training in cell and Tb culture in the category 3 laboratory, casein and gelatin zymography, ELISAs, western analysis, RNase protection assays, RT-PCR, EMSAs, transcription factor assays, promoter-reporter analyses, use of adenoviral vectors and finally, immunohistochemical studies on patient tissue.

The data arising from this project will be of broad scientific interest since interactions between chemokines and MMPs are likely to be involved in many pathological processes from infection to cancer. In addition, the aim is to identify potential targets for development of novel approaches to the medical management of Tb.

The project itself will allow me to develop a subspecialty interest in respiratory infection and successful completion of my PhD will be a stepping stone to my aspired career as an academic physician