By studying the workings of stem cells responsible for the replenishment of sperm in adults, researchers hope to understand why male fertility declines with age, and how to better treat infertility.
Scientists at Kyoto University were especially interested in Myc genes that participate in the self-renewal of stem cells, and in spermatogonial stem cells (SSCs) that are responsible for sperm production. SSCs are the only stem cells that relay genetic data to offspring.
As reported in Genes & Development, the Kyoto team demonstrated how Myc genes regulate the self-replenishment of SSCs in mice, using the activity of glycolysis control. Glycolysis is a primary aspect of our cells' energy producing process.
The discovery was made by injecting two batches of SSCs into lab animal testes. One batch was made up of normal SSC cells, and the other contained Myc gene-suppressed cells. After two months, the scientists found far fewer abnormal (gene-suppressed) SSCs than normal ones. Analysis revealed this occurred because the abnormal SSCs’ capacity for self-renewal was slowed, and it likely compromised sperm production in the affected mice.
Not only did the Myc gene-suppressed SSCs replenish at a diminished rate, it was associated with impaired glycolysis, implying that inadequate cell energy was being generated. “A difference in glycolysis could explain natural differences in SSC self-renewal between mice,” said lead study author Mito Kanatsu-Shinohara. Further experimentation confirmed that enhancing glycolysis in mice can increase their SSCs self-renewal rates.
“These findings could have important implications for infertility research in the future,” says Shinohara. “Stimulating the metabolism of SSCs could improve their proliferation. However, more careful study of the molecular pathways is necessary.”
Source: Science Daily
Photo credit: Iqbal Osman