Prof. Haim Breitbart, Deputy Dean of the Faculty of Medicine and Former Dean of the Mina and Everard Goodman Faculty of Life Sciences, is a leading researcher of cell and developmental biology, best known for his contributions to the field of male fertility.
Breitbart’s research focuses on understanding signal transduction processes involved in the fertilization mechanism in mammals. For this purpose, studies are conducted on bull, ram, mouse and human spermatozoa, as well as mouse eggs. Mouse spermatozoa and eggs are used for the study of the biochemistry of the in vitro fertilization process. Research studies conducted in this laboratory use the most advanced technologies for biochemical characterization of the different systems. The focus is two-fold: breeding of agricultural animals, and finding treatment solutions for human infertility.
For the last 30 years, Breitbart’s group has focused on understanding the molecular mechanisms leading to fertilization, with primary emphasis on the male gamete, the spermatozoon.
During these years, they have discovered new information regarding the cellular mechanisms involved in sperm capacitation and acrosome reaction. As a result, it is well established today that mammalian spermatozoa are unable to fertilize the egg immediately after penetration to the female reproductive tract. They require a period of incubation in the female in order to acquire the capacity to fertilize. During this time, the spermatozoa undergo a process of maturation called capacitation. The binding of capacitated spermatozoon to the egg zona-pellucida induces the sperm to undergo the acrosome reaction which allows its penetration into the egg.
Recently, Breitbart’s research team discovered that protein synthesis occurs in sperm during capacitation, and that this process is essential for the sperm to become fertile. They are the first to describe this phenomenon, contributing a significant breakthrough to our understanding of the molecular mechanisms involved in sperm capacitation. Understanding the precise molecular mechanisms leading to capacitation has implications for various aspects of male infertility and its treatment.
Beitbart’s group has also developed a new assay to determine the ability of the sperm to penetrate the egg, and the likelihood of successful in vitro fertilization. In addition, they are using the information to develop a male contraceptive. They have found that several sperm specific proteins are synthesized during sperm capacitation. The mRNA for these proteins exists in sperm and the specific mRNA can be silenced by specific antisense or by using the RNAi technique. They have already demonstrated that sperm motility and capacitation can be blocked by using specific antisense and are now testing the effect of this antisensein vivo. If it is effective in mice, they will begin clinical testing in humans. Lastly, they have demonstrated that low-power laser irradiation of mouse sperm causes a 40% increase in their fertility rate, and they hope to conduct human clinical testing of this effect as well.