Chinese scientists have developed a new way of delivering DNA to animal and human cells for genetic modification. To do this, they use nanoparticles called artificial viruses by the authors of the study. They help genes to enter the cell nucleus, after which genome editing mechanisms are activated. The biologists' article was published in the ACS Nano journal. It is briefly described on the EurekAlert! Website.
Scientists use various approaches to edit genes in cells, including CRISPR / Cas9 technology. It allows you to precisely cut any selected sections of DNA, thus disabling certain genes. For delivery to eukaryotic cells, viral vectors (created from altered and rendered harmless viruses) are usually used, or plasmids - circular DNA molecules present in bacteria. Since plasmids cannot penetrate into eukaryotic cells themselves, pores are created in the latter using an electric field (electroporation), or they use particles (liposomes) that fuse with the outer membrane.
However, these methods have limitations, since viral vectors cannot carry large DNA fragments and penetrate into all types of cells, and electroporation and liposomes are effective against cell cultures, but not tissues of living organisms.
Image: American Chemical Society
To solve this problem, scientists have created an artificial RRPHC virus. It consists of a fluoropolymer core connected to the CRISPR / Cas9 system, as well as a shell formed by hyaluronic biopolymer, polyethylene glycol, and R8-RGD peptides. It has been shown that hyaluronic biopolymer can bind to proteins on the surface of cancer cells and specific to them.
After the RRPHC is introduced into the cell, the membrane is cleaved by enzymes and the fluoropolymer core is released. In the CRISPR / Cas9 experiment, it entered the nucleus of cancer cells of nude mice using an artificial virus, after which it attacked the MTH1 gene, which is active in many types of malignant tumors. It was found that the concentration of the protein encoded by MTH1 decreased after the introduction of nanoparticles.
According to scientists, their method will also be useful in editing the human genome. For example, it will be possible to remove defective cells from a patient, fix them with CRISPR / Cas9 and transplant them back. Similar experiments have already been carried out in China with the T-lymphocytes of a cancer patient who has been disabled by a gene that suppresses immunity. The RRPHC is expected to increase the efficiency of such operations.
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