In 10 seconds? Scientists have used gene therapy to fix an abnormal cell function causing infertility. They have targeted granulosa cells that regulate the development of oocytes (eggs) in ovaries.
What’s the breakthrough about? It's about restoring fertility in females rather than making people resort to assisted reproduction therapy. One of the causes of female infertility is impaired ovulation. Researchers have managed to ‘repair’ faulty communication between defective cells in the ovaries that blocks ovulation or oogenesis, to use a sciency word… but it's early days as they achieved this in lab mice.
“Gene therapy”… can I get some clarity on this? In (very) simple words, gene therapy is a medical approach that treats or prevents, diseases by gene transfer. Both the EMA (the European Medicines Agency) and the FDA (the US Food and Drug Administration) define gene therapy as a biological medicinal product. This could be a free nucleic acid, viruses, or genetically engineered microorganisms. This new genetic material is inserted in some target cells, through different techniques, to solve particular problems.
So, how did they do it? They used genetically modified mice that don’t produce a particular protein. The protein in question plays an important role in the communication between ovary cells (in this case, the oocyte and the granulosa cells), and in fostering ovarian follicles development. Basically, they’ve created female mice with abnormal oogenesis. The goal of this experiment was to figure out a delivery mechanism to reach the granulosa cells and insert a functional copy of the therapeutic molecule.
Were the researchers successful with the mice? Yes! It was hard because granulosa cells are protected by a shield that prevents harmful substances in the blood to reach the oocyte. So, the team had to find a way to penetrate this barrier. And they did it! They found that a special type of virus (called adeno-associated viruses, AAV) could penetrate this barrier and deliver the therapeutic gene into the nucleus of the cells. In fact, they didn’t just succeed to deliver the therapeutic gene and rescue the damaged granulosa cells but those mice went on to have healthy offspring!