Therapeutically targeting a newly discovered function of Tuberous Sclerosis Complex 2

Tuberous Sclerosis Complex 2 (TSC2) is known to repress mechanistic target of rapamycin (mTOR) and cell growth. This basic discovery was fundamental to better understand an array of human diseases linked to mTOR dysregulation. By working on TSC cell models we now have striking data showing that TSC2 has a second function that drives pathology. This new function of TSC2 is regulated through the transcriptional activation (TA) domain, which is linked to disease traits associated with mTORopathies, epilepsy, peroxisomal disorders, and cancer. Preliminary data indicate that the TA domain regulates key transcription factors involved in redox homeostasis, orchestrating a broad array of cellular processes, including angiogenesis, extracellular matrix deposition, epithelial-to-mesenchymal transition, cell differentiation, lipid metabolism, inflammation, and immune evasion. This project aims to characterise the TA domain of TSC2, uncovering its functional role to orchestrate gene expression linked to redox homeostasis and will explore calcium and hormone signalling (Aim 1). We plan to identify downstream pathways and targets through transcriptomics in cell models harbouring either the TA or GTPase activating protein (GAP) domain mutants of TSC2. This will allow us to screen for clinically viable drugs that modulate these pathways and targets, aiming to address a broader spectrum of pathologies linked to signal dysregulation through this TSC2-TA domain (Aim 2). To further advance clinical applications, Aim 3 focuses on characterising extracellular vesicles (EVs) derived from TSC-disease cells, comparing TA and GAP domain mutants of TSC2 in their pathological cell communication to modulate transcription factor activity within recipient cells. EVs harbour detectable biosignatures that are reflective of TSC pathology. Therefore, we will also determine disease-specific EV biosignatures downstream of the GAP and TA domain of TSC2. In summary, this research will deepen our understanding of TSC function with focus on the TA domain of TSC2, uncover novel therapeutic avenues, and improve clinical management through advancing diagnostic biomarkers that are linked to the GAP- and TA-domain functions of TSC2. Findings obtained will advance our understanding of TSC and mTORopathies, as well as other diseases linked to the dysregulation of the TSC1/2 tumour suppressor complex. This includes cancer that have dysregulated signalling through TSC2.