As many couples trying to conceive will attest, much can go wrong during that fateful meeting of sperm and egg. Now, scientists have identified a new protein eggs use to draw in sperm, which could one day lead to new fertility treatments and contraceptives.
Fertilization is a long chain of molecular events that need to happen in exactly the right way, in the right order, at the right time, and just one step not going to plan can mean the difference between conception and not. As such, for a large percentage of infertile couples the specific reason cannot be identified.
A new study, led by researchers at the University of Sheffield, investigated proteins on the surface of eggs that might help or hinder sperm that are trying to bond with them. The team used thousands of beads as artificial eggs, each of which had different peptides on their surfaces. These were then incubated with sperm, to see which beads – and as such, which peptides – attracted sperm in higher numbers.
The team performed several rounds of these tests, removing beads that failed to attract sperm in high enough numbers. Eventually they were left with beads that had consistently bound sperm from all five donors. On closer inspection, they identified a specific protein that was associated with these successful artificial eggs.
The researchers named this protein MAIA, after the Greek goddess of motherhood. To investigate further, the team inserted the gene associated with MAIA into human cells in culture, and found that these also became more receptive to sperm. This suggests MAIA plays a major role in drawing sperm into the egg to achieve fertilization.
Problems with MAIA may be an overlooked factor in infertility, and now that the protein has been identified it could help scientists develop new treatments to help people conceive – or going the other way, prevent conception.
“Infertility is unexplained in more than half of those who struggle to conceive naturally,” said Professor Harry Moore, lead investigator of the study. “The ingenious artificial fertilization technique which enabled us to identify the MAIA protein will not only allow scientists to better understand the mechanisms of human fertility, but will pave the way for novel ways to treat infertility and revolutionize the design of future contraceptives.”
The research was published in the journal Science Advances.
Source: University of Sheffield