• Cellular aging: A basic paradox elucidat

    From ScienceDaily@1:317/3 to All on Tue Nov 9 21:30:36 2021
    Cellular aging: A basic paradox elucidated

    Date:
    November 9, 2021
    Source:
    University of Montreal Hospital Research Centre (CRCHUM)
    Summary:
    Cancer researchers show for the first time that cellular
    senescence, which occurs when aging cells stop dividing, is caused
    by irreversible damage to the genome rather than simply by telomere
    erosion.



    FULL STORY ==========================================================================
    In a study published in Nucleic Acids Research,the team of cancer
    researcher Francis Rodier, an Universite' de Montre'al professor, shows
    for the first time that cellular senescence, which occurs when aging
    cells stop dividing, is caused by irreversible damage to the genome
    rather than simply by telomere erosion.


    ==========================================================================
    This discovery goes against the scientific model most widely adopted
    in the last 15 years, which is based on one principle: telomeres, caps
    located at the ends of chromosomes whose purpose is to protect genetic information, erode with each cell division. When they get too short,
    they tell the cell to stop dividing, thus preventing damage to its
    DNA. Made dormant, the cell enters senescence.

    For this model to be valid, the inactivation of a single telomere should
    be sufficient to activate the senescence program. Rodier's laboratory
    and many others had already observed that several dysfunctional telomeres
    were necessary.

    "What's most surprising is that, before really entering senescence, the
    cells divide one last time," said Rodier. "In fact, the cell division
    caused by telomere dysfunction is so unstable that it ends up creating
    genetic defects.

    Contrary to what was believed, senescent cells have an abnormal
    genome. That's what we show in our study." Snapshots of the life of a
    cell To achieve such results, Rodier's research team was able to count
    on state-of- the-art imaging equipment funded by the Institut du cancer de?Montre'al.

    "Genetically, we were able to reproduce the phenomenon of cellular aging
    in the laboratory and ensured that all the telomeres of a population of
    cells became dysfunctional," said PhD student Marc-Alexandre Olivier,
    co-first author of the study with former colleague Sabrina Ghadaouia,
    currently pursuing postdoctoral studies in England. "With our equipment,
    we then observed in real time what was happening inside each single cell."
    With time, senescent cells build up in the body and are responsible
    for the development of diseases such as cancer. This study, therefore,
    opens up new research opportunities.

    For example, could telomeres be repaired prior to the senescence phase,
    thereby preventing cellular aging and genomic instability? The scientific community has been debating this potential cellular rejuvenation for
    several years now.

    Nevertheless, these emerging therapeutic approaches still need
    fine-tuning.

    ========================================================================== Story Source: Materials provided by University_of_Montreal_Hospital_Research_Centre_(CRCHUM).

    Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Sabrina Ghadaouia, Marc-Alexandre Olivier, Aure'lie Martinez, Tibila
    Kientega, Jian Qin, Patrick Lambert-Lanteigne, Guillaume B Cardin,
    Chantal Autexier, Nicolas Malaquin, Francis Rodier. Homologous
    recombination-mediated irreversible genome damage underlies
    telomere- induced senescence. Nucleic Acids Research, 2021; DOI:
    10.1093/nar/ gkab965 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2021/11/211109095334.htm

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