A synthetic biology approach for T cell exhaustion

ended

Synthetic Biology has revolutionised approaches for several scientific, industrial and medical applications. These include the development of immunotherapies based on bioengineered cells, most notably engineering of patients T cells with tumor-targeting receptors, the CAR-T cells. Cell-based immunotherapies have shown remarkable clinical success; yet, long-term benefits are hampered by dysfunction of T cells occurring following antigen chronic exposure, a process known as T cell exhaustion. Current treatments of T cell exhaustion are limited and exhibit adverse effects. Synthetic T-rEX aims to reprogram exhausted T-cells using synthetic biology circuits, to implement enhanced and more effective immune cell-based therapies. We will develop specific, self-contained genetic circuits with improved capabilities that minimise the impact on normal cell physiology; by pre-programmed integration of exhaustion-specific intracellular signals, these will rewire T cell activity and restore normal function. Circuits will be developed using a stepwise, bottom-up approach to identify exhaustion-specific inputs by RNA and microRNA-sequencing profile performed on ex vivo exhausted human CD8+ T cells. We will then design (a) synthetic promoters and (b) microRNA-regulated 5’UTR that will compute information processing to trigger output activation. Localised therapy will rely on concerted action of genetically encoded immune-checkpoint blockade and fine-tuning of epigenetic modulators that play a major role in T cell exhaustion. Finally, we will engineer T cells with sensor-actuator synthetic devices that revert exhaustion (T-rEX cells). In summary, our proposal provides a paradigm shift in the development of strategies against T cell exhaustion and a solid break-through towards enhanced natural and cell-based immunotherapy. More broadly, the proposed approach will unleash the potential of synthetic biology to the next level of therapeutic intervention.