CELLULAR AGING: Telomeres & Telomerase, Sirtuins.

A series of video tutorials discussing the topics for undergraduates in Pathology
In this tutorial , i have discussed Cellular Aging
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Cellular aging
• Define cellular aging
• Changes that contribute to cellular aging
• DNA Damage
• Senescence
• Defective protein homeostasis
• Nutrient sensing system

• There is good evidence that aging-induced alterations in cells are an important component of the aging of the organism
• Cellular aging is the result of a progressive decrease in cellular function and viability
• caused by genetic abnormalities
&
• the accumulation of cellular and molecular damage due to the effects of exposure to exogenous influences
• Telomeres are…
• Repetitive DNA sequences at the ends of all human chromosomes
• They contain thousands of repeats of the six-nucleotide sequence, TTAGGG
• In humans there are 46 chromosomes and thus 92 telomeres (one at each end)
• They protect the chromosomes.
• They separate one chromosome from another in the DNA sequence
• Without telomeres, the ends of the chromosomes would be FUSED leading to massive genomic instability.
• Telomeres are also thought to be the "clock" that regulates how many times an individual cell can divide.
• Telomeric sequences shorten each time the DNA replicates.
• Once the telomere shrinks to a certain level, the cell can no longer divide. Its metabolism slows down, it ages, and dies.
• SENESCENCE
• Healthy human cells are MORTAL because they can divide only a finite number of times, growing older each time they divide.
• Thus cells in an elderly person are much older than cells in an infant.
• Telomerase (TEE-LÓM-ER-ACE) is a ribonucleoprotein enzyme complex (a cellular reverse transcriptase) that has been referred to as a cellular IMMORTALIZING enzyme.
• It stabilizes telomere length by adding (TTAGGG) repeats onto the telomeric ends of the chromosomes, thus compensating for the erosion of telomeres that occurs in its absence.
SIRTUINS!
• Family of NAD dependent protein deacetylaces.
• Promotes expression of several genes whose products increase longevity
• Inhibit metabolic activity, reduce apoptosis, decrease the effects of free radicals, they activate DNA repair enzymes,

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Please watch: "WARBURG EFFECT: Hallmark of CANCER. What, Why & How?"
https://www.youtube.com/watch?v=LXaO59IqQm8
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Видео CELLULAR AGING: Telomeres & Telomerase, Sirtuins. канала ilovepathology