Unlike small molecules, macromolecules (proteins, nucleic acids and pathogens) require specific mechanisms to enter cells, such as receptor-mediated endocytosis, micropinocytosis and so on. The research in Laboratory of Macromolecule Drug Delivery (LMDD) is focused on 1) understanding the mechanisms of cellular uptake of macromolecules and 2) developing next-generation delivery technologies.
1. Dissection of mechanisms of macromolecule internalization
In order to understand the key molecules mediating the internalization of macromolecules, we constructed focused CRISPR/Cas9 sgRNA library targeting to surface protein (surfaceome library). Compared with genome-wide CRISPR sgRNA library, the surfaceome library does not contain gene targets that may interfere with the screen process (tumor suppressor genes etc.), thereby dramatically increasing the screening efficiency. Using this library, we have successfully identified host surface proteins that mediated Zika virus infection. We plan to use these focused libraries to understand the internalization mechanisms of macromolecules such as exosome and toxic proteins.
2. Precision genome editing using anti-CRISPR peptides and small molecules
CRISPR/Cas9 is often associated with unwanted off-target gene editing. One major cause of these off-target activity is the accumulated Cas9 nuclease and sgRNA inside cells. Inhibition of the excess CRISPR/Cas9 activity can be a feasible route for improving the genome editing fidelity. Using our house-made EGFP reporter cell line, we have identified lead peptides and small molecules that can suppress CRISPR/Cas9 activity.
3. Zinc finger protein (ZFP)-mediated macromolecule delivery system
Zinc finger protein is the most abundant transcription factors in human. From our previous studies, we have discovered that ZFP can be used as an efficient delivery tool to transport macromolecule cargos such as proteins and nucleic acids into mammalian cells. We have demonstrated that ZFP can mediate efficient delivery of botulinum neurotoxins, superoxide dismutase and targeted nucleases. These delivery technologies have been patented and licensed to biotech startup companies.