Note in Science page
Created Sep 21 11, Updated Nov 03 11 18:54
Aging is not an irreversible process go to comments

A paradigm shift: Adult stem cells can be rejuvenated

Researchers from the Buck institute and Georgia Tech found that while young adult stem cells are able to suppress the transcriptional activity of “junk” ALU genomic elements (integrated remains of old viral infections in Supraprimates) and deal with the damage to the DNA, older adult stem cells are not able to scavenge this transcription. By suppressing the accumulation of toxic transcripts from those ALU elements, they were able to reverse the process of human adult stem cell aging in culture!

image ©

Our results demonstrate that the cytotoxicity of induced Alu repeats is functionally relevant for the human adult stem cell aging. Stable suppression of Alu transcription can reverse the senescent phenotype, reinstating the cells’ self-renewing properties and increasing their plasticity by altering so-called “master” pluripotency regulators.

This is a major finding: cellular senescence and ultimately cellular aging, is not an irreversible process!

They used lenti-virus delivering Alu inhibitory shRNA (Small hairpin RNA) to “silence” / knockdown Alu transcription…
Not yet usable in live humans (although siRNA – without the need to pass via an shRNA precursor expressed by a virus – could be injected ~directly c.f. Performing RNAi Experiments in Animals), but this study represents a paradigm shift!

I think that future studies will have to be performed to determine if those rejuvenated cells are completely equivalent to “young” ones (and do not become cancerous) ... article article

original publication:
Inhibition of activated pericentromeric SINE/Alu repeat transcription in senescent human adult stem cells reinstates self-renewal, Cell Cycle, Volume 10, Issue 17, September 1, 2011 (PMID 21862875)

[Nov 2 2011] in the same vein, a new study (published in Nature journal!) as shown that removing senescent cells somehow rejuvenates mice! Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders

to summary: removing trash (junk genetic element expression, senescent cells) is good for you! ;-)

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