The hallmarks of adult stem cells

by Alexey Bersenev on March 30, 2011 · 3 comments

in educational

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Our knowledge about stem cells is evolving. I’d like to summarize the current understanding of adult stem cell properties as a whole. Recent research has shown there are some common features for all somatic stem cells residing in different organs. Some of these features overlap with embryonic stem cells, some are distinct.

1. Self-renewal
The most important and fundamental quality of stem cells. Self-renewal is defined as an ability of a cell to replicate itself, thereby allowing indefinite replenishment:

Self-renewal is the process by which a stem cell divides asymmetrically or symmetrically to generate one or two daughter stem cells that have a developmental potential similar to the mother cell

(definition from the review)

2. Multipotency
Ability to give progeny of many distinct lineages via differentiation process:

Stem cells whose progeny are of multiple differentiated cell types, but all within a particular tissue, organ, or physiological system.

(ISSCR definition)

Unlike adult stem cells, embryonic stem cells are pluripotent.

3. Niche
Specific anatomical location (microenvironment) within tissue where stem cell resides. Niche is ensuring self-renewal and stem cell properties via signals from surrounding cells, nervous system and mechanical cues.

4. Quiescence and specific cell cycle kinetics
Adult stem cells possess slow cell cycle kinetics with distinct large quiescent and dormant fractions. The ability of cycling stem cells to undergo quiescence and vice versa underlie the system of dynamic equilibrium.

NB: Predominant quiescence as an hallmark of adult stem cells was recently challenged for hematopoietic system.

5. Regenerative potential
Ability to replenish, replace or repair of mature cell types in normal or damaged (pathological) tissue. Regenerative potential could occur through such processes as: differentiation, growth factors release, fusion, horizontal genetic material transfer.

Taken together, the hallmarks indicated above define the adult stem cell. Please let me know if I have missed something.

Related posts:

  1. The model of coexistence 2 populations of adult stem cells
  2. Embryonic vs Adult stem cells wars
  3. Studying hematopoietic stem cells in adult spleen
  4. Reviews: Chemokine-mobilized adult stem cells; defining a better hematopoietic graft by Pelus LM & S. Fukuda
  5. Potential risk of tumor formation from adult stem cell therapy could be underestimated

{ 3 comments… read them below or add one }

Sonja March 30, 2011 at 6:01 am

Thanks – this is a really nice summary!

Reply

Denis English March 30, 2011 at 8:49 am

Alex:

You are an amazing person, let me say at the onset. I am presently encumbered writing the most important paper I have penned during my career and do not have time just now to study your other comments above but I wanted to use your introduction and response to the definition of pluripotentiality above to introduce the scientific community to my theory of Cellular Singlarity. This name, I made up. I get to do that since I edit journals; I think it is a deserved perk. My theory is that, similar to certain aspects and concepts in physics, there exist problems or concepts in biology that are amendable to “proof” and there exist some that by their very nature defy Proof, and therefor shall forever remain a theory. It for example is said that Maxwell and Lorentz proved that light was an electromagnetic wave. In contrast it is said that relativity because of the concepts that the theory presents shall always remain a theory, and by its nature cannot be proven. As a scientist, I never understood what was meant when I read papers entitled, protein structure “solved”, and I dont think I ever will. But that is I think a different problem. Given certain assumptions, some things can, I recon, be proven, but other things defy proof. We have the theory of evolution in biology which I guess is considered to be not amendable to proof.

Here, I for the first time maintain that cellular pluripotentiality cannot be proven. It will always remain a theory unless discounted, and it may soon be. Given the premise that differentiation can be irrersible, an irreversible event, then I maintain that pluripotentiality can never be proven. I do admit that when differentiation is reversible, such as I think it is early after fertilization, then a cell can bear diverse progeny. I can expound more on that later. But apart from that, and a paper inFASEB express concluding that “transdifferentiation” in fact occurs postnatally and that this process is reversible by Rocky Twan, an excellent scientist who misinterpreted his data in that paper (I think), then I herein hypothesize that if pluripotential cells exist, there is no way to prove that.

I must discount the interpretation of experimental results purporting to show complete restoration of an organ system from a single cell injected in vivo, or from cells derived from a single cell in culture then injected in vivo. Certainly, an egg is “pluripotent”. Certainly cells stunned by radiation may be ready, willing and able to proliferate, and given a little prompt, proceed to, but absent these arguments, I challenge the audience to tell how one can prove any cell to be pluripotential.

Personally, I do not think any are.

Denis

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Michael E. Sparks May 26, 2011 at 5:23 pm

Denis,

This is a longshot but I saw that you had posted on here and thought perhaps you could contact me about one of your properties in Indianapolis.

Although I am working on my masters in psychology and am fascinated by stem cell research, I am posting here for other business matters.

If you see this please text me at 317-250-2649.

Thanks you.

Reply

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