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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 dark matter on 5/8/2010 8:34:48 AM , Rating: 2
I don't we will ever be able to prevent ageing. It is such an important part of life that I believe you would have to fundamentally change so much DNA that we would no longer be even human.


By icanhascpu on 5/10/2010 5:44:20 PM , Rating: 2
Aging literally is preventable, its just way out of the reach of humanity right now and for many hundreds of years I would venture to guess. No to mention impractically expensive when we were do discover how to fix the degradation that happens to DNA.

I believe simple slowing of that degradation is going to be the future. We already live on average twice as long as we did a thousand years ago, and that is mainly from medical advances. The huge bottleneck a in human longevity is that degradation. Once that becomes slowed, or even able to regenerate that, mankind will see a huge jump in lifespan.

Saying its a part of life doesn't really mean anything. My computer crashing sometimes is a part of Windows too, but that doesn't stop MS from trying to improve the stability.

Saying they may not even be human from that is silly. Can they still breed with another human? Then they are human. Less syfy channel bro.


"There is a single light of science, and to brighten it anywhere is to brighten it everywhere." -- Isaac Asimov














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