BIOE: Krishanu Saha - "Nanoscale assembly of CRISPR components and nonviral coatings for efficient gene editing and delivery"
(sign-up)Krishanu Saha, Assistant Professor, Department of Biomedical Engineering & Wisconsin Institute for Discovery, University of Wisconsin-Madison
|Time:||11:30 a.m. - 12:30 p.m.|
1265 Digital Computer Lab, 1304 W Springfield Avenue, Urbana, IL
|Event Contact:||Lisa Leininger
Department of Bioengineering
(Please note this seminar is on a Thursday in room 1265 DCL and the start time is 11:30 a.m.)
"Nanoscale assembly of CRISPR components and nonviral coatings for efficient gene editing and delivery"
Abstract: CRISPR ribonucleoproteins (RNPs) can generate programmable gene edits, however imprecise editing and efficient delivery to human cells are key challenges. Here we describe novel biochemical techniques to assemble various biomolecules and coatings with nanoscale precision around a RNP. First, by modifying the sgRNA with a short S1m RNA aptamer, we developed a modular strategy, termed an “S1mplex,” to assemble Cas9 RNPs with biotinylated moieties. Using S1mplexes with biotinylated short oligonucleotides improves the ratio of precise to imprecise editing up to 18-fold over conventional methods approaching a ratio of 4 precise edits to every imprecise mutation, while assembly with fluorescent molecules allows selection and enrichment for cells with multiplexed gene edits. Second, we developed two separate synthetic coatings for nonviral delivery of RNPs to mammalian cells. The “nanocapsule” coating strategy encapsulates Cas9 RNPs into a novel cell-degradable thin polymeric shell that can be decorated with cell targeting ligands and other biomolecules. Nanocapsules frequently outperform commercial liposomal reagents, while having significantly lower toxicity and higher stability. In human pluripotent stem cells in vitro and via subretinal injection into mice in vivo, robust gene editing ~5-20% is observed with nanocapsules. The “polyplex” coating strategy is a pre-polymerized polymer that coats and assembles with S1mplexes and nucleic acids. Polyplexes also have improved cytotoxic properties and enable nonviral delivery of CRISPR machinery with high levels of precise gene edits. Combined, these strategies, which utilize chemically-defined, off-the-shelf reagents, have significant promise for gene editing applications in vitro e.g., drug discovery, disease modeling and in vivo e.g., somatic gene editing.
About the Speaker: Krishanu Saha is an Assistant Professor in the Department of Biomedical Engineering at the University of Wisconsin-Madison. He is also a member of the Wisconsin Institute for Discovery, Carbone Cancer Center, and Stem Cell and Regenerative Medicine Center. Prior to his arrival in Madison, Dr. Saha studied Chemical Engineering at Cornell University and at the University of California in Berkeley. He was a Society in Science: Branco-Weiss fellow at the Whitehead Institute for Biomedical Research at MIT and in the Science and Technology Studies program at Harvard University. Major thrusts of his lab involve gene editing and cell engineering of human cells found in the retina, central nervous system and blood.
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