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Embryonic stem cells - those revered cells that give rise to every cell type in thebody - just got another badge of honor. If they suffer damage thatmakes them a threat to the developing embryo, they swiftly fall ontheir swords for the greater good, according to a study publishedonline in the journal Molecular Cell. The finding offers a new glimpse into the private lives of stemcells that could help scientists use them to grow new neurons orother cells to replace those that have been lost in patients withParkinson's and other diseases. "Despite the huge potential of stemcells for therapeutic use, very few people have actuallyinvestigated their basic biology," said study senior researcherMohanish Deshmukh, PhD, professor of cell and developmental biologyat the University of North Carolina at Chapel Hill. "These resultscould have significant implications from a therapeuticperspective." Of all the important things our bodies' cells do, staying alive isclearly key. But a cell's ability to die when something goes wrongis equally critical. For example, a faulty self-destruct button isone factor that allows cancer cells to proliferate unchecked and cause tumors. Deshmukh and his colleagues discovered stem cells are extremelysensitive to DNA damage, which can be caused by factors likechemicals, radiation or viruses. The experiment showed thatvirtually 100 percent of human embryonic stem cells treated with aDNA-damaging drug killed themselves within 5 hours, as compared to24 hours for other types of cells. "That's an incredibly rapid rateof death," said Deshmukh, who also is a member of the UNCNeuroscience Center and Lineberger Comprehensive Cancer Center The hair-trigger suicidal response is an important adaptation forembryonic stem cells, said the UNC School of Medicine researcher,because a slower response could allow DNA damage to proliferate andharm the embryo. "Mutations that develop in these cells could becatastrophic for the developing organism, so it would make sensefor these cells to be rapidly eliminated." The key to the stem cells' quick response is that they pre-activatea critical protein called Bax, the researchers found. In mostcells, Bax is is kept in an inactive form, waiting for a long chainof events to rouse it into action if the cell becomes damagedenough to kill itself. In human embryonic stem cells, the teamfound Bax standing at attention in its active form in the Golgiapparatus, a part of the cell that processes and modifies proteins. "What these cells do is very clever," said Deshmukh. "They haveactivated Bax, but they've also parked it in a safe littlecompartment - the Golgi." If the cell detects DNA damage, Bax zipsover to the mitochondrion (the cell's power plant), where itsignals other proteins to shut the cell down. It's like starting a 100-yard race at the 80-yard line, saidDeshmukh. You're guaranteed to get to the finish line first becauseyou did most of the work before the race began. However, there arebuilt-in safeguards against a hair trigger activation of death.Pre-activated Bax is housed in the Golgi keeping the protein fromaccidentally triggering cell death when it's not warranted. This extreme sensitivity to DNA damage lasts only a few days duringearly development. After the embryonic stem cells begindifferentiating into early progenitors that give rise to specificcell types (like heart cells or skin cells), Bax reverts to itsinactive state. Additional References Citations. I am an expert from opticalfiberpatchcable.com, while we provides the quality product, such as China Led Dimmable Drivers , Fiber Fan Out Kit, Fiber Optic Adaptor,and more.
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