A gene that weakens sperm function has been identified, could it help develop a male pill?

So far, all oral contraceptives that are effective in preventing unwanted pregnancies have been designed for women, and there are no effective contraceptives for men. The identification of a gene that influences the number, shape and movement of genes, reportedly paves the way for the development of an effective non-hormonal male contraceptive, according to a new report by researchers at Washington State University. increase.

ARRDC5 expression is conserved in mammalian tests and required for normal sperm morphogenesis | Nature Communications


New genetic target for male contraception identified – WSU Insider


As a contraceptive method for women, there are options such as taking oral contraceptive pills (pills) and emergency contraceptive pills (after pills), but the current situation is that condoms and pipe cuts are the only methods for men.

Sperm is the cell that carries male genes and is the only mammalian cell that functions outside the body. A normally formed sperm moves through the female reproductive tract by flagellar motility and fertilizes an egg by fusion of the head and egg cell membranes.

However, in some people, defects may occur in this series of movements and conditions, and the symptoms are ``oligospermia (low sperm count)'', ``asthenozoospermia (low sperm motility)'', and ``teratozoospermia''. (Lack of normal sperm)” is known to occur. These are collectively called 'OAT (Oligoasthenoteratospermia)', but the mechanism that can cause OAT has not been elucidated.

Mariana Giacetti and colleagues at Washington State University conducted germ cell analysis to identify gene expression that could be responsible for these symptoms. When Giacetti et al. created a list of candidate genes that have not been reported in the scientific literature so far, `` α-arrestin protein encoding gene (Arrdc5) '' emerges as a leading candidate.

When Giacetti et al. used CRISPR-Cas9 gene editing to create mice that do not produce the Arrdc5 gene product, the amount of sperm in Arrdc5-deficient mice was 28% lower than normal, and the movement was 2.8 of normal mice. About 98% of the sperm had abnormalities in the head and abdomen. Based on these conditions, the mouse was determined to have OAT.

Since this gene is found in mammals in general, the research team says that this finding can be expected to be applied not only to mice but also to humans and other animals. ``If this gene is inactivated or inhibited in the male body, it will produce eggs and sperm that cannot be fertilized.This gene is a good target for the development of male contraceptives.'' I was.

Existing research is investigating methods of sperm suppression by hormone therapy, but the current situation is that there are high hurdles because hormone administration may affect bone mass, muscle strength, and red blood cell production. If a contraceptive drug is developed targeting Arrdc5 identified by Mr. Giacetti et al., it may be possible to provide a simpler method that does not administer hormones.

It also showed the possibility of developing an alternative to castration surgery as a method of controlling reproduction not only in humans but also in livestock.

'Rather than making the sperm incapable of producing sperm, we should prevent the sperm from functioning properly,' said John Autry, who was involved in the research. Developing a way to control population growth and stop unwanted pregnancies is a truly important goal for the future of humanity.'

in Science, Posted by log1p_kr