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HSCs are responsible for keeping us alive by granting us an eternal supply of blood cells.  (Source: Microscopy Inc.)

Rice University bioengineers Oleg Igoshin (left) and Jatin Narula may have found the switch that tells HSCs when to differentiate and self renew.  (Source: Jeff Fitlow/Rice University)
Master regulator could allow for easy growth direction, organ creation

Scientists are racing towards a future vision in which humans can regrow failing organs and essentially obtain immortality.  Along the way, they're shooting for the more obtainable aim of curing a number of diseases (cancer, Alzheimer's, Parkinson's, and paralysis, to list but a few) using stem cells.

A critical problem though is how to direct stem cells to become the proper tissue type.  Within the human body, there are a rich variety of cells -- endothelial cells, muscle cells, blood cells, osteoblasts (bone), and nerve cells to name but a few.  At some point in the development of the human body, these cell lines were created by a biochemical signal which instructing stem cells to become the particular cell type.

Experimentalists at Cambridge University and Rice bioengineers Oleg Igoshin and Jatin Narula have examined one of these critical biochemical signals.  Based on a computer model developed at Rice and experiments at Cambridge, they believe that a trio of regulatory proteins known as the "Scl-Gata2-Fli1 triad" controls the differentiation of hematopoietic stem cells (HSCs), the self-renewing cells the body uses to make new blood cells.

In healthy adult humans, each day HSCs are responsible for the creation of 100 billion new white and red blood cells.  HSCs are also capable of "self-renewing" if the bone marrow is damaged.

The research at Rice delved into looking at the three regulatory proteins and developing an mathematical model for how they interacted with HSCs.  In their model, the proteins act as a bistable switch, with two states -- "replenish HSC" and "differentiate".  The system ignores extraneous signals and throws the switch only when a signal persisted.

Igoshin, an assistant professor in bioengineering at Rice, comments, "We don't yet have the experimental verification that this is the master-level regulator for HSCs, but based on our model, we can say that it has all the properties that we would expect to find in a master-level regulator."

Jatin Narula, a Rice graduate student, adds, "In examining the results from the model, we found the triad did have the characteristics of a master regulator.  The first time it's switched on, all the cells stay on. It also handles deactivation in a controlled manner, so that some cells differentiate and get deactivated and others don't. Finally, it has the ability to discern whether or not the level of signal is present only for a short burst or for a significantly long time."

Rice researchers hope that the regulatory triad motif reappears in other types of stem cells, possibly leading to more breakthroughs.

The results of the study are published in the journal 
PLoS Computational Biology.



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By pepito perez on 5/7/2010 4:46:21 PM , Rating: 2
In fairness I don't care about the extremist in either side. You will find fanatics everywhere. What really concerns me is when a significant number of educated and intelligent people choose to question the scientific community and method over an specific topic.

No, global warming is NOT a fabrication. As with any other scientific conclusion there is an error margin and in this case might be bigger due to the magnitude and complexity of the subject. So let's say that instead of 90% of screwing the planet, there is "just" a 50% or even a 30% probability (whoever thinks is 0% qualifies for homo but not for sapiens). Let me ask you: With how many bullets would you be willing to play Russian roulette?

Do people doubt of the scientific community and the scientific method when they switch on their computer, take a plain, open Google Earth? I wonder then why some people feel free to challenge that same scientific community and scientific method when it comes to evolution, global warming, the holocaust or any other subject they choose they don't like.


By ekv on 5/8/2010 3:28:19 AM , Rating: 2
Thanks for nothing. You clearly did not read the ref's posted.
quote:
Global warming alarmists relentlessly chant that there is scientific "consensus" that the "science is settled." Yet now we are told that somehow the main body for promoting the climate change agenda "neglected" to tell the world that the science wasn't settled.
The scientific method, for your information, involves advancing a theory based on repeatable observation. Other scientists then examine said theory, attempt to duplicate the results and either shoot down the theory or support it.

Telling me the science is settled when it isn't ... is just a lie. I can pull statistics out of my head just like anybody else. But then read what Disraeli wrote "There are three kinds of lies: lies, damned lies and statistics." If I believed like Chicken Little that the sky is falling then I'd be trying to make decisions based on a false dilemma. Similarly for your Russian roulette.

Your last paragraph is absolutely opaque and undecipherable, i.e. it does not make any sense. In general, just like AGW proponents.


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