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Intracellular Molecular Delivery

Controlling the intracellular localization of synthetic molecules is essential for effective drug development. Nonetheless, rational control over intracellular trafficking of small molecules has remained a challenge. The Kelley lab has engineered peptide-based conjugates to deduce rules for manipulating intracellular localization of bioactive molecules. These compounds also provide useful tools for the cellular delivery of chemically or biologically active species and can be used to study organelle-specific processes.

We have used these vectors to delivery a variety of bioactive cargo to mitochondria.  Mitochondria are very interesting compartments within the eukaryotic cell with a unique evolutionary history.  The bacterial origin of mitochondria and retention of a genome differentiate this organelle from others within the cell.  Because of the impermeable nature of the mitochondrial membranes, genetic manipulation of the mitochondrial is difficult and as a result little is know about the processes within the organelle that involve nucleic acids.

We recently developed a peptide-based delivery vector that can carry reactive cargo into the mitochondria of live mammalian cells.  By attaching agents that generate reactive oxygen species or alkylation damage, we can site-specifically probe the cellular response to these insults and deconvolute this response from that resulting from nuclear damage.  This approach is revealing new insights into how mitochondrial DNA damage is responded to, and has also indicated that the makeup of mitochondria make them susceptible to other types of biomolecular damage.

 In addition, clinically-utilized anticancer drugs that typically act within the nucleus have been shown to have interesting activities when delivered to mitochondria, and we have also developed a strategy to detoxify antimicrobials within human cells by sequestering the drugs within this organelle.

Featured publications:

Lei, E. K.; Kelley, S. O. Delivery and Release of Small-Molecule Probes in Mitochondria Using Traceless Linkers.
J. Am. Chem. Soc. 2017, 139 (28), 9455–9458. https://doi.org/10.1021/jacs.7b04415.

Wisnovsky, S.; Jean, S. R.; Kelley, S. O. Mitochondrial DNA Repair and Replication Proteins Revealed by Targeted Chemical Probes.
Nature Chemical Biology 2016, 12 (7), 567–573. https://doi.org/10.1038/nchembio.2102.

Wisnovsky, S. P.; Wilson, J. J.; Radford, R. J.; Pereira, M. P.; Chan, M. R.; Laposa, R. R.; Lippard, S. J.; Kelley, S. O. Targeting Mitochondrial DNA with a Platinum-Based Anticancer Agent.
Chem. Biol. 2013, 20 (11), 1323–1328. https://doi.org/10.1016/j.chembiol.2013.08.010.

Chamberlain, G. R.; Tulumello, D. V.; Kelley, S. O. Targeted Delivery of Doxorubicin to Mitochondria.
ACS Chem. Biol. 2013, 8 (7), 1389–1395. https://doi.org/10.1021/cb400095v.

Pereira, M. P.; Kelley, S. O. Maximizing the Therapeutic Window of an Antimicrobial Drug by Imparting Mitochondrial Sequestration in Human Cells.
J. Am. Chem. Soc. 2011, 133 (10), 3260–3263. https://doi.org/10.1021/ja110246u.

Fonseca, S. B.; Pereira, M. P.; Mourtada, R.; Gronda, M.; Horton, K. L.; Hurren, R.; Minden, M. D.; Schimmer, A. D.; Kelley, S. O. Rerouting Chlorambucil to Mitochondria Combats Drug Deactivation and Resistance in Cancer Cells. Chem. Biol. 2011, 18 (4), 445–453.https://doi.org/10.1016/j.chembiol.2011.02.010.

Horton, K. L.; Stewart, K. M.; Fonseca, S. B.; Guo, Q.; Kelley, S. O. Mitochondria-Penetrating Peptides.
Chem. Biol. 2008, 15 (4), 375–382. https://doi.org/10.1016/j.chembiol.2008.03.015.