Inhibition of T-bet-mediated transcriptional elongation as a novel therapeutic target for inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a condition that can lead to distressing symptoms including bloody diarrhoea, abdominal pain and weight loss. Complications of IBD include cancer, intestinal failure and bowel perforation requiring emergency surgery. Even with the most effective of treatments, a large proportion of patient's fail to respond and continue to suffer with debilitating symptoms. We are interested in discovering more targeted therapies that may ultimately benefit these patients.

We believe that IBD is caused by over-activity of the immune system, particularly in the gut. A protein called T-bet plays a fundamental role in maintaining a healthy and regulated immune system. Research has shown that some patients with IBD have abnormal T-bet activity and that this may lead to immune over-activity and ultimately IBD.

We would like to test the effects of blocking the activity of T-bet with new experimental treatments to see if this can treat IBD. We will initially treat mice with IBD to ensure the treatment is safe and effective before studying the effects on colonic specimens from patients with IBD. We hope to discover a new and effective treatment that can be developed, tested and benefit patients in the future.

Inflammatory bowel disease (IBD) affects 240,000 people in the UK, costing the NHS £720m per annum. Despite the advent of biological therapies, 30% of patients fail to respond and develop complications including bowel perforation, colorectal cancer and intestinal failure. The T-box transcription factor T-bet is essential for maintaining immune homeostasis and is implicated in the pathogenesis of IBD. T-bet is upregulated in the colonic mucosa of Crohn's disease patients, driving Th1 cell activation and inflammation. Our recent work has identified a strong association between IBD and genetic polymorphisms that give rise to abnormal T-bet binding. We hypothesise that inhibiting T-bet mediated transcriptional elongation will abrogate intestinal inflammation in preclinical models of IBD and in in vitro human IBD. We will use cyclin-dependent kinase 9 (CDK9) inhibitors (Flavopiridol, AT7591, and LDC000067) that disrupt T-bet binding to enhancer elements of Th1 gene targets.

We aim to investigate the effects of inhibiting T-bet function in innate (anti-CD40 Rag-/-) and adaptive (naïve T-cell transfer) pre-clinical models of colitis. In vitro assessment will be performed by culturing colonic explants with CDK9 inhibitors for 24 hours. Pro-inflammatory cytokines and canonical T-bet target genes will then be measured using ELISA. The experiment will be repeated in vivo, delivering the compounds via intraperitoneal injection. Response will be measured by assessing clinical parameters and colonic histology. In parallel, we will study the therapeutic potential of CDK9 inhibition on lamina propria mononuclear cells (LPMCs) of IBD patients. We will isolate LPMCs from colonic biopsies and stimulate these in the presence of CDK9 inhibitors. Cytokine production will be measured by flow cytometry to determine response to treatment. Ultimately, we hope to identify a novel treatment strategy for IBD, paving the way for effective targeted therapies which will benefit patients.

Our proposal presents the unique opportunity to evaluate the effects of inhibiting T-bet-mediated transcriptional elongation in pre-clinical models of colitis, ultimately to expand our understanding of the role of T-bet in the pathogenesis of inflammatory bowel disease (IBD). We will disseminate our findings through scientific meetings and publications in high impact journals. This will have academic impact on the scientific community including immunologists and mucosal biologists with a special interest in inflammatory disorders and T-bet biology.

By testing the therapeutic potential of CDK9 inhibitors ex vivo in human IBD, we hope to identify a novel therapeutic strategy, which has the potential for commercial application. The objective of our proposal is to demonstrate that the inhibition of T-bet-mediated transcriptional elongation has therapeutic potential and identify a suitable compound which can be developed in collaboration with the pharmaceutical industry. We hope that the outcome of our proposal will pave the way for early phase clinical trials. Longer term, we believe that CDK9 inhibitors could play an important role in the management of inflammatory bowel disease. IBD affects 240,000 people in the UK costing the NHS over £700 million per annum. There are therefore great societal and economic benefits in delivering a new and effective treatment.

There is great interest in the use of CDK inhibitors in managing solid organ tumours, haematological malignancies and auto-inflammatory disorders. In these areas, research has not extended beyond early phase clinical trials. Our study will provide greater insight into the functional effects of CDK9 inhibition on innate and adaptive immune responses which will be directly relevant to other fields of medicine including rheumatology, oncology and haematology.

The institutions supporting our work including the Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London will also benefit through ongoing use of its advanced immune monitoring facilities. We hope that undertaking cutting-edge translational research will lead to high impact publications and presentations contributing to the university's excellent academic reputation.

From a personal perspective, the project will allow me to develop fundamental skills as a researcher. I will gain further experience of critical appraisal, patient recruitment, laboratory techniques, bioinformatics and scientific communication. I hope that the project will culminate in a PhD and will form a stepping stone to go on to a Clinical Lectureship, providing the opportunity to complete my specialist training whilst continuing my research interests.