PROTACs Regulating HIF in Mucosal Inflammation

University Of Colorado Denver, Aurora CO

Investigators

Abstract

Project Summary Inflammatory bowel disease (IBD) represents a group of chronic mucosal inflammatory disorders, including Crohn's disease and ulcerative colitis. Many IBD patients have limited therapeutic options. Oxygen metabolism and hypoxia play prominent roles in healthy intestinal tissue and energetic shifts during active inflammation. Hypoxia triggers the temporal stabilization of the transcription factors hypoxia-inducible factors HIF1 and HIF2, which are essential in maintaining intestinal homeostasis. HIF-1/2 are regulated by a family of prolyl hydroxylases (PHDs). Inhibition of PHDs results in transient stabilization of HIF-1/2 and thus, PHD inhibitors (PHDi) have become attractive targets for the therapeutic treatment of IBD. We have investigated the chemical knockdown of PHDs by “hijacking the proteasome system” using proteolysis targeting chimeras (PROTACs), heterobifunctional compounds that degrade proteins of interest. PROTACs advantages include enhanced specificity, higher potency, and sustained inhibition. In ongoing studies, we have produced a panel of PHD targeting PROTACs. In vitro, we observe significant PHD2 degradation and modest HIF stabilization at nanomolar concentrations, a 2-3 log increase in potency compared to PHDi. Importantly, the wound healing capacity of epithelial cells is significantly enhanced. These results warrant further investigation as there is vast room for improvement in developing fine-tuned PROTACs. The intent of this proposal is to design HIF stabilizing PROTACs and elucidate their role in barrier formation and wound healing as supported by metabolic shifts. The end goal is to reveal the therapeutic potential of PROTAC-HIF stabilization in murine models of IBD. The applicant, Dr. Ornelas Sanchez, has established a scientific niche in which to build a foundation for independent research on the development of PROTACs that influence inflammatory pathways. Dr. Ornelas Sanchez and his mentor, Dr. Colgan, assembled a mentorship committee to regularly meet as a group to provide feedback, critique the research plans, monitor publications, and provide career advice. Of note, he will train under the supervision of Dr. Reigan to learn molecular modeling of PROTACs. Furthermore, we have identified coursework to expand his knowledge in computational modeling, fundamental molecular biology, and cellular biology. Dr. Ornelas Sanchez will submit his work to present at conferences specific to his research to share his results, network with colleagues and potential collaborators, and get valuable feedback. His development will benefit from continued participation in the Mucosal Inflammation Program (MIP), a multi-disciplinary, multi- departmental program initiated to study mechanisms of mucosal inflammation and resolution. The MIP fosters a unique environment for collaboration between physician and research scientists and establishes an environment for young investigators to flourish and develop. The facilities and resources available to and development plan built for Dr. Ornelas provide an ideal environment and path towards his successful transition to independence.