Investigating tuberculosis by engineering human granulomas

Tuberculosis continues to kill almost 2 million people per year worldwide and is becoming increasingly resistant to the drug therapy, because treatment has remained unchanged for over 30 years. Tuberculosis research relies heavily on animal studies, but these are simply not the same as disease in patients. We will develop an entirely new way of studying tuberculosis infection by using human cells and the tuberculosis bacteria sprayed into tiny balls incorporating fibres that support the human lung. We will use this model to study how the body responds to tuberculosis infection and investigate new treatments which may reduce the lung damage in patients with tuberculosis and also speed up the killing of the bacteria. This approach will replace the need for extensive screening experiments in laboratory animals and accelerate the development of new treatments which are urgently needed. The approach will also be valid to investigate other human diseases by using cells in culture to model the complex 3-dimensional interactions that happen in patients, and so has the potential to replace animal experiments used to study a wide array of human diseases.

Tuberculosis (TB) remains a global health pandemic but treatment has remained unchanged for over 30 years. TB research relies extensively on animal studies, including mice, guinea pigs, rabbits and non-human primates, but no model accurately reflects disease in man. We have recently identified matrix metalloproteinases (MMPs) as critical drives of immunopathology in TB and have shown that matrix destruction is a key step leading to TB immunopathology. In this fellowship, I will develop an in vitro granuloma model of TB infection by exploiting bioelectrospray technology to generate spheroids incorporating primary human cells, Mycobacterium tuberculosis (Mtb) and extracellular matrix components. I will determine the effect of different spheroid matrix composition on granuloma formation and MMP and cytokine production. Next, I will investigate regulation of intracellular signalling pathways and mycobacterial growth by the extracellular matrix, and incorporate divergent Mtb lineages and cells from patients with TB. Finally, I will develop the model to screen for new antimycobacterial compounds active within a granuloma and also to assess efficacy of vaccination strategies ex vivo from patients. These studies will dissect TB immunopathology in an entirely novel in vitro system to identify new therapeutic candidates and evaluate vaccine responses, replacing the need for extensive studies in suboptimal animal models. The 3-dimensional cell culture platform will also be applicable to other human diseases where cell-cell and cell-matrix interactions are important, and so has the potential to replace animal modelling in a wide range of diseases.

Impacts will be related both to the tuberculosis (TB) field and also more widely to the knowledge economy. The work will be of interest to pharmaceutical companies as it is directly translational and is addressing Cooksey's first gap in the translational pathway. The 3-dimensional cellular culture model which I will optimise will permit in vitro study of complex events in vivo, and therefore permit replacement of animal modelling where multicellular events require analysis within the context of physiological extracellular matrix. This will be applicable to the TB field, potentially replacing studies of drug screens in mice and also initial analysis of vaccine efficacy, but also to other diseases involving 3-dimensional cell-matrix interactions, such as atherosclerosis, cancer invasion, rheumatoid arthritis and pulmonary fibrosis. Therefore, the potential to replace animal modelling with an advanced 3-dimensional cell culture system is broad and extends beyond infectious diseases.

Specifically for the aims of the fellowship, tuberculosis is a disease of global importance, infecting a third of the world's population and causing approximately 8 million new cases per year and killing 1.7 million people per year. Despite the World Health Organisation highlighting that TB was a global health emergency in 1994, the disease incidence remains static and treatment has remained unchanged for over 30 years. We will develop a better model to improve the understanding of the pathophysiology of TB and to identify new therapeutic strategies to limit the immune-mediated tissue damage that results in morbidity and mortality. We will investigate a novel, innovative methodology cutting across bioengineering, biology and cellular imaging which have wide applicability to other research fields. The bio-electrospraying of viable cells into 3-dimensional granulomas impregnated with components of the extracellular matrix will be relevant to all diseases where matrix remodelling is involved. I propose to develop as a researcher competent in an extensive range of cutting-edge research techniques, including bio-electrospray methodology, quantitative confocal imaging and bioluminescence to establish a 3-dimensional cellular platform that can be applied to a wide range of diseases.

Our studies are of direct translational impact and so we anticipate pharmaceutical engagement and the potential to attract research and develop investment. We are already in discussion with Roche about testing one of their specific inhibitors (Ro32-3555) in our model system, and since this is a compound of proven safety in man, these studies have the potential to proceed rapidly to clinical trials. Similarly, we are discussing with GSK regarding accessing their portfolio of MMP inhibitors under their "Open Innovation" scheme. Inhibitors of matrix metalloproteinases have potential to reduce immune-mediated tissue damage in inflammatory diseases and although initial trials of non-specific MMP inhibitors were disappointing in cancer, they may have potential to limit immunopathology in other diseases. Tuberculosis can be considered the prototypic tissue destructive disease and so proving the efficacy of MMP inhibition in TB models will not only facilitate clinical trials to reduce morbidity and mortality in patients with TB, it will also prove the proof-of-concept for the efficacy of MMP inhibition in diverse inflammatory diseases.
Ultimately, our studies should identify candidate compounds to go forward to clinical trials to reduce matrix destruction and therefore morbidity and mortality in TB. The models developed and the inhibitors identified will also have potential to improve outcomes in other diseases characterised by pathological destruction of the extracellular matrix, replacing the need for extensive animal modelling where pathology does not accurately reflect disease in man.