A recent study has revealed that glucose (blood sugar) plays a critical role as a master regulator of tissue differentiation, a process by which stem cells transform into specialized cells that make up the body's various tissues.
The study was conducted by researchers at Stanford University School of Medicine (USA), and its results were published in the journal Cell Stem Cell on March 21. The website EurekAlert also reported on it.
A chance discovery
Glucose wasn't the researchers' primary target when they began exploring molecules that stimulate cell differentiation. They conducted extensive experiments on stem cells derived from human skin, which were on their way to becoming mature keratinocytes—the dominant cells in the skin's outer layer. Using advanced techniques, they measured fluctuations in biomolecule concentrations during the differentiation process.
They concluded that molecules whose abundance increased significantly during differentiation could play a key role in this process.
The researchers identified 193 suspect molecules. Surprisingly, instead of observing a decrease in glucose levels, they observed a marked increase in its levels as differentiation progressed.
This increase led the team to reevaluate the importance of glucose. Using fluorescent or radioactive glucose analogs, the researchers were able to visualize glucose dynamics within cells during differentiation.
As cells progressed through their specialization pathway, the increase in light intensity observed in the cells indicated increasing glucose activity, suggesting that glucose acts as a key signal promoting differentiation.
Research on other human cell types—including fat, bone, and some developing white blood cells—has shown similar patterns, indicating that glucose's role in tissue differentiation appears to be widespread.
Much more than just an energy source
These results generated considerable interest, so the researchers further investigated the impact of varying glucose levels on keratinocyte differentiation under various experimental conditions. They discovered that human skin organoids—skin tissues reconstructed in the lab and grown in a medium mimicking real skin—failed to differentiate properly when glucose levels were lower than normal.
The solution was as simple as it was unexpected: introduce a glucose analogue that could not be metabolized. This intervention was enough to restore differentiation, reinforcing the idea that glucose plays a role that goes beyond its energy function.
Dr. Paul Khavari, MD, Ph.D., Chief of Dermatology at Stanford University, said:
« It was a shock. We were convinced that glucose was only an energy source. "But these non-metabolizable analogs support differentiation just as much as classic glucose. "
Researchers now hope to better understand the role of glucose in healthy and diseased cells. This new insight could help treat complications related to abnormal glucose regulation in diseases such as diabetes, or even in the development of cancer—a disorder often associated with undifferentiated cells and uncontrolled cell growth.
This study thus paves the way for future research, highlighting the multiple facets that simple molecules like glucose can play in cellular processes. As the scientific community reconsiders the place of glucose in cell biology, it is becoming increasingly clear that unsuspected functions could also be discovered in other small molecules.
