Designer Molecular Probes for Biomedical Applications

University Of Pennsylvania, Philadelphia PA

Investigators

Linked publications, trials & patents

Abstract

PROJECT SUMMARY For two decades the PI has led a research program developing molecular probes that have yielded breakthroughs in Chemical Biology, Radiology, Cellular Genomics/Transcriptomics, Anesthesiology, and Photochemistry. Since 2019, the PI has published 20 peer-reviewed research manuscripts and 2 review articles with NIH-MIRA support, and several related papers. The PI has mentored 2 postdoctoral fellows to successful job placement, 4 graduate students to Ph.D. completion and chemistry careers, and 6 undergraduates to STEM Ph.D. programs. The MIRA grant continues to provide primary support to 8 graduate students and 2 undergraduates who are carrying out the studies that underpin this renewal application. The PI’s service confirms a strong commitment to scientific review, undergraduate and graduate education, outreach, community building, and junior faculty mentoring. This MIRA grant renewal will build on several exciting advances made in the current funding cycle. In the first project, several new small-molecule capsules and proteins have been developed for xenon binding. Key principles have been elucidated for controlling the xenon exchange rate in these systems, and a suite of new tools will drive the development of sensitive xenon contrast agents (Xe CAs) for molecular imaging and also lead to improved understanding of xenon anesthesia and analgesia. Critically, the FDA approved hyperpolarized Xe-129 for human lung magnetic resonance imaging (MRI) in Dec, 2022. Imaging equipment has been assembled at UPenn with collaborators (Kadlecek and Gade), and we propose to perform cutting-edge Xe-129 MRI studies and investigate Xe CAs developed in the PI’s laboratory for lung cancer detection in mice. Notably, a Xe CA employing ribose-binding protein (RBP) led to the discovery of 5 mM ribose in HeLa cells, 1000x more than previously estimated. This has spawned a second project, which is the development of the first useful fluorescence resonance energy transfer (FRET)-based sensor for real-time quantitation of ribose levels in mammalian cells. This offers the opportunity to study natural fluctuations in ribose (likely as a function of cell cycle), and also explore enzymatic pathways that we hypothesize convert ribose-5-phosphate (originating from the pentose phosphate pathway) to ribose. Finally, a third project stems from the development of fluorescein- and Cy5-labeled siRNA molecules as first-in-class ratiometric pH probes for elucidating details of endosomal entrapment and release and improving delivery of therapeutic oligonucleotides to skeletal muscle. Novel bicyclic oligonucleotides are proposed for achieving potent enzyme inhibition.