Researchers discover how cells make decisions during embryonic development

The early stages of embryonic development hold numerous enigmas that, once unraveled, can provide valuable insights into birth defects and facilitate the development of regenerative medicine treatments. Researchers at Monash University’s Australian Regenerative Medicine Institute (ARMI) have shed light on a crucial phase in mammalian embryonic development through innovative imaging techniques, as reported in Nature Communications.

Lead researcher Dr. Jennifer Zenker explained that within a few days of embryogenesis, when the embryo consists of 16 cells, a critical decision must be made. The embryo must determine which cells will contribute to its own development and which will become extra-embryonic tissue like the placenta.

In their study, the research team uncovered the mechanisms behind this decision-making process by examining the internal organization of individual cells in the early embryo.

“RNA, specifically ribonucleic acid, plays a pivotal role in this process. At the 16-cell stage, different types of RNA, including rRNAs, mRNAs, and tRNAs, are sorted to the apical and basal sides of the cell. The distribution of these RNA subtypes determines the fate of the next generation of cells in the embryo,” Dr. Zenker elaborated.

Interestingly, while most mRNAs and tRNAs remain localized at the apical side, the majority of rRNA molecules travel to the basal side by hitchhiking on lysosomes, which are organelles within the cell. Despite containing less overall RNA content, the apical sides of the outer 16-cell stage cells house the complete collection of RNAs and other factors necessary for protein production.

Conversely, the crowded basal side primarily contains rRNAs. Daughter cells that inherit the more active protein factories from the apical side become more specialized and develop into future placental cells. On the other hand, daughter cells that retain pluripotency—the ability to differentiate into any cell type in the adult organism—receive the less translationally active bulk of rRNA.

Such cell fate decisions, including the one described above, are pivotal during development as they determine how these early cells ultimately differentiate into specific cell types like skin cells, heart muscle cells, or brain cells. The ability to orchestrate cell fate has profound implications for regenerative medicine, as it opens up avenues for generating stem cell-based treatments for various diseases and conditions.

Dr. Zenker highlighted the significance of early cellular organization in influencing the trajectory of cell fate, stating that their research could pave the way for predicting and guiding such decisions.

Source: Monash University

Leave a Comment