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Biotech Science

Major Advance In Understanding Cell Reprogramming 54

Posted by kdawson from the stemming-the-tide dept.
Researchers at the Harvard Stem Cell Institute and Massachusetts General Hospital have taken a major step toward eventually being able to reprogram adult cells to an embryonic stem cell-like state without the use of viruses or cancer-causing genes. In a paper released online today by the journal Cell Stem Cell, Konrad Hochedlinger and colleagues report that they have both discovered how long adult cells need to be exposed to reprogramming factors before they convert to an embryonic-like state, and have "defined the sequence of events that occur during reprogramming."
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Major Advance In Understanding Cell Reprogramming More

Major Advance In Understanding Cell Reprogramming

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  • few comments from TA (Score:3, Informative)

    by mapkinase ( 958129 ) on Friday February 15, 2008 @12:44PM (#22435646) Homepage Journal
    Organism: mouse. Source cells: fibroblasts [wikipedia.org]:

    Mouse embryonic fibroblasts (MEFs) are often used as "feeder cells" in human embryonic stem cell research. However, many researchers are gradually phasing out MEF's in favor of culture media with precisely defined ingredients of exclusively human derivation. Further, the difficulty of exclusively using human derivation for media supplements is most often solved by the use of "defined media" where the supplements are synthetic and achieve the primary goal of eliminating the chance of contamination from derivative sources.

    What is interesting is that they are using adult cells.
    Article says [sciencedirect.com], that

    Fibroblasts were isolated from tail-tip biopsies of newborn (3-8 days of age) mice as well as from embryos and expanded in fibroblast medium
    • I'm not sure whether you read the actual article or where you got that last quote from but it specifically says they aren't using "adult" cells. Unless by adult you mean differentiated, but most cell populations in a newborn will still differ from cells taken from a mature adult in many ways, so thats a confusing way to put it.
    • I'm afraid I don't catch you point. I don't have time right now to read the article, but both embryonic fibroblasts and adult fibroblasts will work about the same for the feeder cells. The cells they're actually culturing though, you'd be more interested in the adult fibroblasts since those are easier to obtain in humans and would be more of a direct correlation.

      In other words, I would assume they're talking about fibroblasts that they reprogrammed, not fibroblasts they used as feeder cells.

      I realize that

  • A amjor milestone for stem cell therapies... (Score:3, Informative)

    by ZonkerWilliam ( 953437 ) * on Friday February 15, 2008 @12:45PM (#22435654) Journal
    This is actually a very major step because up until now most of the stem cell used caused cancerous tumors in the test subject, a definite problem and stumbling block.
    • "A major milestone..."! Damn dyslexia...

    • Re: (Score:2, Informative)

      by repapetilto ( 1219852 )
      Where does it say anything about the activity of the cells after they are implanted in an organism? As far as I can tell without paying anything they just figured out which transcription factors need to be expressed and in what order and for how long in order for a cell to be in a pluripotent state, a series of signaling factors trigger that gene expression, and developed a way to tell whether the cells are pluripotent or not. Nothing about what your talking about...
      • Well I'll be the first to say I'm not a stem cell researcher, I've tried to read up on it though. I've read there is plenty of problems with iPS cells causing tumors, and when I read the statement from the slashdot submission; major step toward eventually being able to reprogram adult cells to an embryonic stem cell-like state without the use of viruses or cancer-causing genes I made the assumption (bad on my part) the submitter was drawing the conclusion from the article. So shoot me.
    • From the abstract it seems they have only figured out the events to reprogramming. The abstract says nothing about figuring out how to re-differentiate these cells. The end product is the same. This is a step towards solving that, but it's not there yet. These cells will still produce teratomas if you were to inject them into SCID mice or people.

  • This is a big deal (Score:3, Interesting)

    by PIPBoy3000 ( 619296 ) on Friday February 15, 2008 @12:45PM (#22435660)
    I read the abstract (the article is for-purchase) and it looks like they have a better feel for what it takes to turn adult cells into embryonic stems cells. Furthermore, they identified cell markers that let you better isolate these cells from other cells that haven't made the transitions between the two states.

    I think what you'll start seeing is much better efficiencies for upcoming cloning experiments (currently it's incredibly poor), as well as people starting to talk about theraputic stem cell treatments (since you can better guarantee the "purity" of the cells you're injecting into people).

  • Thank you! (Score:5, Insightful)

    by kenthorvath ( 225950 ) on Friday February 15, 2008 @12:50PM (#22435734)
    Thank you for being one of the few people who actually links to the original publication when citing a scientific advance. I can't tell you how aggravating it is to try to look these things up when half the time they don't even tell you the name of the researcher who made the break through.

  • Cell aging (Score:2, Interesting)

    by bindo ( 82607 )
    I was under the impression that this is half the problem. Build replacements.

    The other half is rejuvenate cells and especially their DNA. Are the two separate or do embrionic cells behave differently in the handling of telomers as I understand gametes do ?

    If not this is useful to repair broken bits and pieces not to rejuvenate aging tissue.
    bindo

    • do embrionic cells behave differently in the handling of telomers as I understand gametes do ?

      The summary says:

      "reactivation of endogenous Oct4, Sox2, telomerase, and the silent X chromosome mark late events in the reprogramming process."
      • Telomerase, for those of you who don't know, is an enzyme that seems to extend the telomere, one step in making the cell capable of indefinite proliferation. I belive there is normal telomerase activity in stem cells, definitely in germ cells, and unfortunately cancer cells.

        I also have to point out that I think all the papers on iPS (induced pluripotent cells, the reprogrammed cells they're talking about) specifically measure and report telomerase activity in the cells. It's just one of the many suprising

        • Re: (Score:1)

          by bindo ( 82607 )
          thanks !
          that was exactly what I wanted someone to clarify. It's not that you get birth with telomerase's use set into your mind :)

          for all I knew telomerase was the enzyme that cut the telomers :))

          cheers
          BindO

    • Re: (Score:2)

      by cnettel ( 836611 )
      Existing cells in situ won't be changed. Injecting these in existing tissue will, supposedly, add into the empty spots of the cellular matrix and so could add a kind of rejuvenating effect. Any attempt to activate telomerase in general in existing tissue is outright dangerous, considering that it only takes a single cell out of a billion to seed a cancer.

  • Can it run Linux? (Score:4, Funny)

    by Fex303 ( 557896 ) on Friday February 15, 2008 @01:42PM (#22436478)
    So, now that we're reprogramming mouse cells, how long till someone gets Linux working on one? And would that be the greatest hardware hack of all time?

    I can't wait till I'm my own websever.

    • Yeah, um, I can barely get my video card drivers to install on my laptop with Linux. I can't imagine trying to configure my eye-sight to work and see that my heart maintains a steady resting 55bpm rate.

      Until some uber commmunity member writes those drivers, I'll stick with my body's OEM configuration, although I'm sure properly impelemented Linux could help me get rid of some of the 'bloat' :)
    • ...but when your cells get Slashdotted you'll think again.
    • I can't wait till I'm my own websever.

      Yeah, and I can't wait until someone gets the Microsoft web server therapy, and after a couple weeks starts walking around screaming "Hacked by Chinese!"
  • I fully oppose this up until the day I get cancer.
  • This identifies major steps and provides some information about them. Fully understanding what is going on in there and being able to manipulate it could still be quite a ways off. This is an advance, but has the typical one of a thousand steps look such work usally has.
  • That they can revert adult cells to a stem-cell status is a major leap forward, IMO.

    So far the most reliable source of stem cells has been obtained from harvesting dead babies. Anything that will put a stop to that, and give us a potentially more abundant source is a good thing.

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