Sperm are constantly replenished in the adult male entire body. Understanding the workings of stem cells responsible for this renewal is expected to shed light on why male fertility diminishes with age group, and possibly lead to new treatments for infertility.
“So-called Myc genes play an important part in stem cells’ ability to self-renew, ” explains Kyoto University’s Takashi Shinohara, who is interested specifically in spermatogonial stem cells (SSCs), which are responsible for producing sperm. Shinohara adds that SSCs are unique, because they are “the just stem cells that transmit genetic information to children. ”
In a new report in Genetics & Development, the Shinohara lab demonstrates how the Myc gene regulates the self-renewal of mouse SSCs, with a process of glycolysis control. Glycolysis is a key part of cells’ energy-making mechanism.
The scientists injected 2 types of SSCs into mouse testes: normal cells in certain, and Myc gene-suppressed in others. Two months later, these people found that the total number of abnormal SSCs was significantly fewer than normal ones. Gene analysis showed that the convenience of self-renewal had been compromised, with possibly important implications pertaining to sperm production in these mice.
“We discovered changes in the expression of genes that would slow the cellular cycle, ” says Shinohara.
In other words, under control SSCs could self-renew, but at a slower than regular rate. Further study showed that this diminished rate has been accompanied by impaired glycolysis, suggesting that the cells were not producing sufficient energy.
“A difference in glycolysis could explain natural differences in SSC self-renewal between rodents, ” elaborates Mito Kanatsu-Shinohara, first-author of the paper. “DBA/2 and B6 are two mouse types in which SSCs are know to self-renew at different rates. inch
Further experiments confirmed that glycolysis has been more active in the cells of DBA/2 mice. Moreover, separating cells from B6 mice and treating them with specific chemicals that enhanced glycolysis could increase the proliferation price to levels comparable with DBA/2.
“These findings could have important implications for infertility research later on, ” says Shinohara. “Stimulating the metabolism of SSCs could improve their proliferation. However , more careful study from the molecular pathways is necessary. ”
Materials provided by Kyoto University . Note: Content may be edited for style plus length.