Production of functional exosomes by cell nanoperforation as a new strategy of gene therapy

The mechanism of exosomes release triggered by cell nanoperforation Scientists of chemical and Biomolecular Engineering at Ohio State University have developed a cell nano perforation technology, which can produce exosomes containing therapeutic mRNA and targeted peptide on a large scale Based on this, a new gene therapy strategy has the potential to reverse the disease process The study was published on December 16 in the journal Nature biological engineering https://doi.org/10.1038/s41551-019-0485-1 In 2017, Dr L James Lee and his colleagues announced a new discovery of regenerative medicine called tissue nanotransfection (TNT) The technology uses a nanotechnology based chip to deliver biological substances directly to the skin, transforming adult cells into any type of cell for treatment in patients The researchers further studied the mechanism behind the success of TNT and found that exosomes are the secret of transporting regenerative substances to tissues below the skin surface Exosomes are vesicles released by cells as a way of communicating with other cells Because of their large number and no immune response, they are gradually popularized as biological friendly carriers of therapeutic materials The key to gene therapy is to find a way for relatively large genetic instructions to exist in their tiny bodies on a scale that can produce therapeutic effects However, the insertion of exogenous nucleic acids, especially large mRNA, into the exosomes secreted by cells leads to a reduction in production Therefore, the researchers proposed a method of cell nanofiltration (CNP) to produce a large number of exosomes containing therapeutic mRNA and targeted peptide, which can induce human cells to spit out millions of exosomes, which can be used as nano carriers containing drugs after collection and purification The researchers placed about one million donated cells (such as mesenchymal cells collected from human fat) on the nano engineered silicon wafer and injected the synthesized DNA into the donor cells by using electrical stimulation The result of this DNA forced feeding is that the cells need to discharge unnecessary substances as part of DNA transcription messenger RNA, and repair the holes on the cell membrane Compared with the whole electroporation and other exosomes production strategies, the exosomes produced by the technology are up to 50 times, while the growth of exosomes mRNA transcripts is more than 1000 times, even from cells with low basal secretion level, which shows that the technology has scalability and can produce enough nanoparticles for human body CNP produces a large number of vesicles with mRNA transcription Of course, for any gene therapy, it is essential to know which genes need to be transmitted to solve medical problems In this work, the researchers chose to test the results of glioma brain tumors by passing a gene called PTEN, a cancer suppressor gene PTEN mutations that turn off inhibition allow cancer cells to grow uncontrollably In the mouse model of glioma with defects of phosphatase in situ and tensin homologue (PTEN), the exosomes containing mRNA restored tumor inhibition, enhanced tumor growth inhibition and increased survival rate Exosomes can be used as a universal nucleic acid carrier for transcription In vivo therapeutic efficacy of CNP generated exosomes in U87 glioma in situ model Exosomes are nontoxic and do not trigger immune responses They can be found almost anywhere in the human body, including through the blood-brain barrier However, most drugs cannot enter the brain Tests in mice have shown that the labeled exosomes are more likely to spread to brain tumors and slow down their growth than the substances used as controls; because they can enter the brain safely, the drug delivery system is also expected to be further used in nervous system diseases such as Alzheimer's disease and Parkinson's disease.