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ФЕНОМЕН "СТАЦИОНАРНОГО СТАРЕНИЯ" КЛЕТОЧНЫХ КУЛЬТУР: ТРИДЦАТЬ ЛЕТ СПУСТЯ А.Н.Хохлов Сектор эволюционной цитогеронтологии, биологический факультет МГУ имени М.В.Ломоносова, Москва, Россия [email protected]. Cell Senescence. In culture experiments а la Hayflick , researchers - PowerPoint PPT Presentation
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ФЕНОМЕН "СТАЦИОНАРНОГО СТАРЕНИЯ" КЛЕТОЧНЫХ КУЛЬТУР: ТРИДЦАТЬ ЛЕТ ФЕНОМЕН "СТАЦИОНАРНОГО СТАРЕНИЯ" КЛЕТОЧНЫХ КУЛЬТУР: ТРИДЦАТЬ ЛЕТ СПУСТЯСПУСТЯ
А.Н.ХохловА.Н.Хохлов
Сектор эволюционной цитогеронтологии, биологический факультет МГУ имени М.В.Ломоносова, Москва, РоссияСектор эволюционной цитогеронтологии, биологический факультет МГУ имени М.В.Ломоносова, Москва, Россия
[email protected]@mail.bio.msu.ru
Cell SenescenceCell Senescence
In culture experiments а la Hayflick, researchersestimate the replicative capacity of cells by counting the number of times a culturecan be split before the cells stop dividing. Trypsin is added to free the cells from the extracellular matrix, and cultures are grown until cells carpet the floor of the flasks. This protocol spawned the legendary Hayflick limit (from Hopkin, 2001).
• Hayflick’s phenomenon (IOW - “cell senescence”; unfortunately, last years this term, in my opinion, has rather often been used incorrectly by those who relate it to so called DNA damage response) – limited normal cell proliferation in vitro and in vivo (Population Doubling Level limit)• From the first to the last passage of “senescing” cells they change in the same way as cells of aging multicellular organism• We cannot explain why we age just with the help of the Hayflick’s phenomenon (say, the most important organs – brain and heart – contain a lot of postmitotic cells like neurons or cardiomyocytes) • The Hayflick’s phenomenon is defined by a set of various correlations only
However, now we know how the Hayflick’s phenomenon is realized (thanks to Alexei
Olovnikov!)
Хохлов А.Н., Чиркова Е.Ю., Ушаков В.Л.Хохлов А.Н., Чиркова Е.Ю., Ушаков В.Л.
Использование стационарных культур Использование стационарных культур для изучения механизмов клеточного для изучения механизмов клеточного
старениястарения
В сб.: Первый съезд Белорус. общества В сб.: Первый съезд Белорус. общества геронтологов и гериатров. Тез. докл. геронтологов и гериатров. Тез. докл.
Минск, 1983, 188-189Минск, 1983, 188-189
THEORY OF AGINGCell proliferation restriction is the main cause of accumulation in cells of DNA
damage inducing, in turn, other damageand, as a result, cell death
PROPOSED MODELStationary cell cultures (it is assumed
that under in vitro cell proliferationrestriction cells accumulate the damage
similar to those in cells aging in vivo)
PRIMARY CAUSE OF AGINGDNA damage
ALL OTHER AGE-DEPENDENTCHANGES, AGE DISEASES
INCREASE OF ORGANISM’SDEATH PROBABILITY
Influence on this stageallows to find out whetherthe factor investigated isgeroprotector or geropromoter
Influence on this stageby geroprotector or geropromoter modulatesthe rate of aging onlytemporarily
Cell aging is the accumulation in a cell population of various
types of damage identical to the
damage arising in senescing
multicellular organism
Schematic representation of cultured cell “stationary phase aging” phenomenon
Cel
l d
ensi
ty (
rela
tive
un
its)
Time after subcultivation (days)
Survival curve of Chinese hamster stationary cell culture (solid line – experimental points; dotted line – approximation by the Gompertz equation;
straight line – mortality rate changes with time)
??
Telomeres and TelomeraseTelomeres and Telomerase
«Age» changes shown to really occur in stationary
cell cultures• Accumulation of DNA breaks and DNA-protein cross-
links• Accumulation of 8-oxo-2’-deoxyguanosine in DNA• Inhibition of poly-ADP-ribosylation of chromatin proteins• DNA demethylation• Changes of spontaneous sister chromatid exchange
level• Plasma membrane changes• Nuclear structure modulations• Decrease of the rate of mitogen-stimulated cell cycling
and of cell colony-forming ability
«Stationary phase aging» experiments have been already
carried out on:
• Normal and transformed human and animal cells
• Plant cells
• Bacteria
• Mycoplasmas
• Yeasts
BacteriaBacteria
YeastsYeasts
20122012
Thanks for your attention and patienceThanks for your attention and patience, , sincerely yours,sincerely yours,
AN KhAN Khokhlovokhlov
If you want to make God laugh – If you want to make God laugh – describe to Him your theory of describe to Him your theory of
agingaging
Naturally, anybody from the Naturally, anybody from the audience has the right to object to audience has the right to object to me. And I can certainly agree with me. And I can certainly agree with
him.him.
But then we'll both be wrong - But then we'll both be wrong - ..