In today’s culture negativity is usually frowned upon; maintaining a positive outlook is almost essential to a successful scientific career, but an innovative team of researchers have put some negativity to good use in improving transfection of genome editing complexes using negatively charged proteins and nucleic acid transfection reagents.
Conventional protein-based therapeutics usually focus on extracellular targets, due to the inability of proteins to spontaneously penetrate mammalian cellular barriers. Research has shown that nucleic acids can be protected via liposomal complexation and effectively delivered to cells.
Feeling a little adventurous, John A. Zuris and colleagues at Harvard University decided to venture into the possibility of delivering therapeutic protein cargo directly to cells.
To effectively deliver their desired cargo to cells of interests, the team smartly designed protein complexes that allow for endocytosis and protect against enzymatic degradation by endogenous proteases.
Specifically, Zuris and colleagues engineered fuse proteins with supernegatively charged GFP with the complex protected by cationic lipids and deliver the complex into cultured mammalian cells.
Essentially what they did was fuse the protein or complex of interest to a very negatively charged protein, while still retaining activity. They then surrounded this negatively charged fusion with a bunch of positively charged lipids, to neutralize the overall charge.
Then entire thing could now get past cellular membranes (which like lipids) and deliver the protein fusion package into the cell and even into the nucleus.
Now this can be used to get all sorts of therapeutic proteins into a cell. But it also holds the potential to do so much more.
Cas9 is involved with several DNA recombination systems, including site-specific editing of genomic DNA, actually allowing direct genetic changes to be done.
Using their new delivery system, they increases the amount of Cas9 complexes that made it into the nucleus 10-fold from previous procedures resulting in up to 80% of the genomes being modified in the test systems
And these test systems include the living hair cells inside the inner ears of mice. We already know that using a virus to deliver a gene to hair cells can restore hearing.
What happens when we can do it directly and permanently?
Yes there are possible risks but the benefits are great also. We will adapt.