The researchers examined a signaling pathway called TOR that the cells use to gauge nutrition levels and stress, said study senior author Dr. Julian A. Martinez-Agosto, an assistant professor of human genetics and pediatrics and a researcher with the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA.
“We wondered how an organism knows how many blood cells to make and when to make them in the context of injury and repair to tissue. In particular, we wondered how the blood progenitor cells sense that change and know when it’s time to make more blood cells,” Martinez-Agosto said. “We found that the TOR pathway uses these two genes to regulate its function and, when activated, it expands or increases the number of blood progenitor cells in the fly’s blood.”
The study appears Sept. 5, 2012 in the advance online issue of the peer-reviewed journal Development.
Michelle Dragojlovic-Munther, a graduate student in the Martinez-Agosto laboratory and first author of the study, found that cells with increased activity of TOR have a competitive advantage, allowing them to divide and make more of themselves so they can make blood. These progenitors, Dragojlovic-Munther found, also have high levels of reactive oxygen species (ROS) - ions or very small molecules that include free radicals – which are known to damage cells and can predispose humans to aging and heart disease. But in this case, the ROS proved valuable.
The precursors, Martinez-Agosto said, were producing ROS all the time and when TOR was activated, the levels increased dramatically. Too much ROS caused them to divide more than normal. If they treated the flies with antioxidants, which reduce ROS levels, the cells would develop normally.
The finding could be important because the TOR pathway is abnormally activated in many cancers, and it may be possible to target the levels of ROS, which may help regulate the pathway.
“What this study may be telling us is that too much ROS is causing more cells to divide and we may be able to target therapies that reduce ROS to significantly improve the condition,” Martinez-Agosto said, adding that specifically targeted antioxidants might be a potential treatment in certain subsets of blood disorders. “Sometimes that pathway is working more than it should, and we need the right amount of ROS for balance. It’s like Goldilocks, there can’t be too little or too much. We need it just right.”
Going forward, Martinez-Agosto and his team will try to determine where the ROS is coming from and perhaps discover an enzyme that may be a good target for therapeutics. They know that the higher ROS levels in blood progenitors are not coming from mitochondria, the cell’s power source, but have not identified how they are being produced.
“This study highlights mechanistic differences between TSC and PTEN on TOR function and demonstrates the multifaceted roles of a nutrient-sensing pathway in orchestrating proliferation and differentiation of myeloid-specific blood progenitors through regulation of ROS levels and the resulting myeloproliferative disorder when deregulated,” the study states.
The study was funded by a Ruth L. Kirschstein National Research Service Award from the National Institutes of Health (GM007185) and the David Geffen School of Medicine at UCLA.
The stem cell center was launched in 2005 with a UCLA commitment of $20 million over five years. A $20 million gift from the Eli and Edythe Broad Foundation in 2007 resulted in the renaming of the center. With more than 200 members, the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research is committed to a multi-disciplinary, integrated collaboration of scientific, academic and medical disciplines for the purpose of understanding adult and human embryonic stem cells. The center supports innovation, excellence and the highest ethical standards focused on stem cell research with the intent of facilitating basic scientific inquiry directed towards future clinical applications to treat disease. The center is a collaboration of the David Geffen School of Medicine, UCLA’s Jonsson Cancer Center, the Henry Samueli School of Engineering and Applied Science and the UCLA College of Letters and Science. To learn more about the center, visit our web site at http://www.stemcell.ucla.edu.
Kim Irwin | Newswise Science News
Further reports about: > Broad Institute > Dragojlovic-Munther > Medicine > Precursor > Regenerative Therapien > Stem cell innovation > blood cell > blood flow > cell death > clinical application > embryonic stem cell > fly > fresh fruit > genes > human embryonic stem cell > methanol fuel cells > progenitor cells > suppressor
Molecular Force Sensors
20.09.2017 | Max-Planck-Institut für Biochemie
Foster tadpoles trigger parental instinct in poison frogs
20.09.2017 | Veterinärmedizinische Universität Wien
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
20.09.2017 | Life Sciences
20.09.2017 | Power and Electrical Engineering
20.09.2017 | Physics and Astronomy