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Cell proliferation and ku protein expression in ageing humans
D Frasca1, P Barattini, C Goso
1Laboratory of Immunology, ENEA CR Casaccia, Rome, Italy. frasca@casaccia.enea.it
Mechanisms of Ageing and Development
|April 16, 1998
Summary
Ageing impairs immune cell proliferation and cytokine production, but not significantly the expression of ku protein (a DNA damage recognition factor). This suggests DNA repair decline in aging is only partly due to reduced ku protein levels.
Area of Science:
- Immunology
- Gerontology
- Molecular Biology
Background:
- Aging is associated with increased DNA damage, including single and double-strand breaks in lymphocytes.
- This DNA damage can lead to decreased efficiency in DNA replication and repair mechanisms in elderly individuals.
Purpose of the Study:
- To investigate the relationship between cell proliferation and nuclear ku protein expression in humans across different ages.
- To assess how aging impacts the immune system's response, specifically mitotic responsiveness and cytokine production.
Main Methods:
- Peripheral blood lymphocytes (PBL) from 43 subjects of varying ages were PHA-activated.
- Stimulation index and Th1/Th2 cytokine production were evaluated.
- Gel retardation assays were used to assess the presence and activity of the ku 70/80 heterodimer in nuclear extracts of activated lymphocytes.
Main Results:
- Aging significantly affects mitotic responsiveness and cytokine production in lymphocytes.
- The expression and functional activity of the ku 70/80 protein were only marginally affected by age.
- Age-related decline in DNA repair efficiency is not solely explained by reduced ku protein levels.
Conclusions:
- While aging impacts immune cell proliferation and cytokine balance, the key DNA damage recognition protein, ku 70/80, remains largely unaffected.
- The findings suggest that age-related DNA repair deficits are multifactorial and only partially linked to diminished ku protein expression.