A research group led by Tomoko Sakamoto, a researcher at Kyoto University, has clarified the process by which normal sperm morphology is generated by the interaction between "Sertoli cells" present in the testis and sperm cells, and "actin cells" in the Sertoli cells. It was shown that abnormalities in the "skeletal system" are one of the causes of male infertility.The development of new treatments for male infertility is expected.
In recent years, the declining birthrate has become a social problem, and the diagnosis and treatment of infertility has become an urgent issue.About 10-15% of couples who want to become pregnant are infertile, and about half of them are thought to be due to the male side.Most of the causes of male infertility are spermatogenic disorders, but the cause is unknown and there is no cure.However, previous research reports have shown that close interaction between sperm cells and Sertoli cells, the sustentacular cells present in the testis, is important for normal spermatogenesis.
During the sperm formation process, the research group found that proteins called "mDia1" and "mDia3" polymerize reticulated actin in Sertoli cells, producing continuous contractile actomyosin and adhering between Sertoli cells and sperm cells. It was found that the formation and maintenance contributed to the formation of normal sperm morphology.It was also confirmed that deficiency of both mDia1 and mDia3 causes disorders in the formation and maintenance of adhesion between spermatids and Sertoli cells, resulting in spermatogenic hypoplasia.These results have been elucidated using a super-resolution microscope and single-molecule imaging that can be observed in nanometers (one billionth of a meter).
The results of this study suggest that abnormalities in the actin cytoskeleton system in Sertoli cells are one of the causes of male infertility.It is expected that it will be applied to the development of new diagnosis and treatment of male infertility in the future.
