Description of Technology:

The Transforming Growth Factor Beta (TGF-ß) ligands (i.e., TGF-ß1, -ß2, -ß3) are key regulatory proteins in animal physiology. Disruption of normal TGF-ß signaling is associated with many diseases from cancer to fibrosis. In mice and humans, TGF-ß activates TGF-ß receptors (e.g., TGFBR1), which activates SMAD proteins that alter gene expression and contribute to tumorigenesis.  Reliable animal models are essential for the study of TGF-ß signaling. A previously developed animal model for TGF-ß signaling utilizes a luciferase expression system under the control of SMAD protein responsive promoter elements (Lin et al., 2005, J. Immunol). The luciferase-based reporter mouse requires administering luciferin for bioluminescence detection. Another previously developed model is a SMAD protein-responsive, green fluorescent protein (GFP)-based reporter mouse (Neptune et al., 2003, Nat. Genet.); however, the model is no longer available. Thus, there remains a need for novel reporter animal models to study TGF-ß signaling.

NCI investigators designed an enhanced GFP (eGFP)-based reporter construct that is more sensitive to SMAD3 activation than other existing reporter constructs. Expression of eGFP is driven by an artificial enhancer element consisting of six repeats of a strong SMAD3 binding element. This reporter was greater than ten times more sensitive in vitro than the CAGA12-based reporter, another commonly used construct to detect TGF-ß signaling.  Using CRISPR/Cas9 technology, the inventors knocked this reporter construct into the Rosa26 locus, a ubiquitously expressed gene in most cells of the mouse. This strategy allows identification of tissues and cells in which signaling of TGF-βs are endogenously active during normal development, tissue homeostasis, and disease.

The mouse model is currently undergoing further validation using genetic and pharmacological approaches. It is available for licensing.

Potential Commercial Applications:

• Development of oncology therapeutics
• Developing of fibrosis therapeutics
• Pre-clinical in vivo model to study TGF-β signaling and pathway antagonists
• Pre-clinical model for TGF-β/SMAD3 disease states

Competitive Advantages:

• No requirement for luciferin injections
• Higher sensitivity for SMAD3 activation than other reporters