RSS 1.0Faculty, Student Works School of Medicine
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Radiolabeling of human mesenchymal stem cells for imaging of intraarterial delivery to the brainMesenchymal stem cells (MSCs) are highly promising therapeutic agents. However, unknown biodistribution upon transplantation limits the understanding of their therapeutic effects. This limitation particularly affects advanced and more precise intraarterial routes of cell delivery. Intra-arterial delivery of cellular therapies might be highly beneficial due to the first-pass effect, lowering total cell dose; however, imaging might be instrumental in achieving high precision. Magnetic labeling was used for this purpose, but it interferes with diagnostic MRI and has low specificity on follow-up scans. Radiolabeling and PET imaging may address both drawbacks, although radiolabeling conditions were never studied systematically, and efficiencies needed to be higher to adapt methods of low-dose intra-arterial interventions. We hypothesize that radiolabeling of human mesenchymal stem cells might be beneficial by yielding higher sensitivity over a longer period and will provide quantitative results.
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SARS-CoV and SARS-CoV-2 Nucleocapsid Function is Affected by Inhibiting Mitochondrial ROS Release by CNPOverexpression of a protein called 2’, 3’-cyclic nucleotide 3’-phosphodiesterase (CNP) inhibits SARS-CoV-2 replication by localizing to and preventing depolarization of mitochondria. SARS-CoV-2 infection causes depolarization to release reactive oxygen species (ROS) from mitochondria, which is thought to aid in the viral nucleocapsid’s (N) function in virion assembly. This project explores two hypothetical mechanisms by which inhibition of ROS release affects the N protein and disrupts virion assembly. The first hypothesis is that cytoplasmic ROS are required for N protein dimerization, which is required for its function. The second hypothesis is that cytoplasmic ROS are required for efficient binding of the N protein to the viral genome. We used transient transfection to express and study the N protein; however, this means there is no infection and no stimulus for ROS release. We therefore analyzed N dimerization status in the presence and absence of hydrogen peroxide (H₂O₂). If the N protein dimerizes in the presence of H₂O₂ but not in its absence, it would suggest that ROS release is required for dimerization, which could affect virion assembly. Using immunoprecipitation (IP) and qPCR, we can isolate the N protein and determine the amount of viral genome bound. We hypothesize that the presence of H2O2 would result in more viral RNA being captured, whereas in its absence, the N protein would have no or significantly less RNA attached. Ultimately, this suggests that inhibition of ROS release disrupts the binding of the viral genome to the N protein. A better understanding of the mechanism by which the later stages of viral replication are hindered can be used to develop more effective therapeutic treatments.