Study Provides New Insight on Stem Cell Function

Researchers in the Department of Biomedical Genetics have unraveled one of the key molecular mechanisms that regulate stem cell behavior, a discovery that could provide important insight into regenerative medicine and certain forms of cancer.

The study – led by Benoit Biteau, Ph.D. – appears in the journal Cell Reports, and was conducted in fruit flies, or drosophila.  While diminutive in stature, fruit flies have proven to be an invaluable research tool and have made oversized contributions to medicine, particularly in the fields of molecular biology and genetics.

Benoit and his colleagues focused on a transcription factor called Sox21a which is uniquely found in the stem cells of the drosophila intestine.  Transcription factors are proteins that control the expression of genes and, subsequently, help regulate cellular activity.  Sox21a is the equivalent of Sox2, a transcription factor found in humans that is known to play an important role in the function of stem cells and cell reprogramming.

Many tissues in the human body harbor a reservoir of stem cells whose primary function is to repair damaged tissue.  When cells die, they will send out signals in the form of small proteins called cytokines which activate stress signaling pathways in neighboring stem cells.

In the experiments in the new study, the stress pathways ultimately converge to induce the expression of Sox21a in fruit flies, which, in turn, activates the genetic instructions that cause the stem cells to divide and proliferate. 

While these mechanisms are essential for the process of repairing tissue, they may also play a role in certain types of cancers in which Sox2 is overexpressed – possibly due to chronic stress – and the stem cells multiply in an uncontrolled manner, forming tumors. 

The findings provide researchers with new model to continue to explore the mechanisms of stem cell biology – particularly the factors that control cell division – in a genetically responsive animal model.