Age-related changes of apoptotic cell death in human lymphocytes
Introduction
Programmed cell death (PCD) or apoptosis is of particular interest in aging, as it is thought to play an important role in various age-related degenerative diseases. Apoptosis of white blood cells could be one reason for the decrease of the total number of leukocytes and the decrease of the immune response with aging related to cancer, infections, and autoimmune disorders [3]. Several changes in lymphocytes have been observed related to aging: diminished synthesis of growth and survive factors [46], [51], impaired intracellular calcium regulation [18], different surface molecule expression [43], and defects of signal transduction [36]. Some of these pathological changes are additionally altered in patients with Alzheimer’s disease (AD), but are not present in vascular dementia [13], [14], [15], [17]. In order to differentiate common and divergent mechanisms of an enhanced susceptibility of lymphocytes to apoptosis in aging and sporadic AD, we investigated in detail the molecular basis of enhanced apoptosis in aged human lymphocytes.
Oxidative stress increases with aging and leads to enhanced cellular damage (e.g. lipidperoxidation, protein oxidation, DNA damage (for review see ref. [10]). In addition, reactive oxygen species (ROS) can trigger cells to undergo programmed cell death and can act as second messenger by influencing transcription factors like NF-κB and AP-1. Increased oxidative stress and decreased ability to cope with ROS could amplify apoptotic cell death in aging lymphocytes. Bcl-2 acts in an antioxidative and antiapoptotic way and can interfere with the apoptotic pathway [7], [47].
One of the best known and characterized surface receptors related to PCD in lymphocytes is Apo1/Fas (CD95), a member of the tumor necrosis factor (TNF) superfamily. Stimulation of this receptor by binding to its physiological ligand (Fas-L) or an agonistic anti-Fas antibody leads to apoptosis via a distinct pathway [26]. In addition, activated lymphocytes express the α-chain of the IL2-receptor (CD25) and the MHC class-II related molecule HLA-DR. Lymphocytes bearing these surface molecules or activation markers [4] show enhanced sensitivity to apoptosis upon stimulation of these receptors. Accumulation of chronically activated lymphocytes seems to be one reason for the higher susceptibility to apoptotic cell death probably leading to a lowered leukocyte number in aged individuals. In the present study, we evaluated the basal, spontaneous, activation-, and agent-induced apoptosis and ROS of native and activated peripheral human lymphocytes. In addition, basal expression of activation markers (CD25, CD95, and HLA-DR) and Bcl-2 was determined.
Section snippets
Subjects
Blood samples were taken from n = 85 healthy subjects (55 women and 30 men) between 15 and 93 years. There were 20 women and 12 men in the aged group (n = 32; aged over 60 years, mean age 73.8 ± 8.3 years) and 25 women and 9 men in the group of young controls (n = 34; age under 35 years, mean age 26.4 ± 5.1 years). The remainders were part of the intermediate ages shown in Fig. 3, Fig. 4, Fig. 6. Subjects with psychiatric and neurodegenerative disorders or acute infections were excluded. In
Basal and spontaneous apoptosis are increased in lymphocytes of elderly subjects
Using PI staining, we quantified sub-G1-DNA content in lymphocytes from healthy elderly and young controls. Fig. 1 shows the histogram plots of PI-stained lymphocytes of two representative subjects. Student’s t-test revealed that the percentage of basal apoptotic nuclei in freshly isolated lymphocytes was significantly elevated in aged subjects compared to young controls (means ± SEM: old, 1.35 ± 0.20% versus young, 0.84 ± 0.11%; ∗, P < 0.05; Fig. 2 a). In addition, we found a significantly
Discussion
Previous results of our group reported an increased content of basal and dRib-induced apoptotic cells in PBMC from patients with Alzheimer’s disease relative to age-matched controls [13], [40]. This effect is probably not related to the physiological process of immunosenescence. In addition, apoptosis is a hallmark in brains derived from Alzheimer’s patients, possibly associated with states of increased oxidative stress [8], [45], [49], [52]. Similar alterations could also be detected in
Acknowledgements
This work was supported by grants from the Alzheimer Forschung Frankfurt and Fonds der chemischen Industrie.
References (53)
- et al.
Behavioural, physiological and morphological analysis of a line of apolipoprotein E knockout mouse
Neuroscience
(1998) - et al.
Oxidative stress as a mediator of apoptosis
Immunol Today
(1994) - et al.
Correlates of p53- and Fas (CD95)-mediated apoptosis in Alzheimer’s disease
J Neurol Sci
(1997) - et al.
Free intracellular calcium in peripheral cells in Alzheimer’s disease
Neurobiol Aging
(1997) - et al.
β-Amyloid protein enhances the mitogen-induced calcium response in circulating human lymphocytes
FEBS Lett
(1993) - et al.
Down-regulation of free intracellular calcium in dissociated brain cells of aged mice and rats
Life Sci
(1996) - et al.
Alteration of proteins regulating apoptosis, Bcl-2, Bcl-x, Bax, Bak, Bad, ICH-1 and CPP32, in Alzheimer’s disease
Brain Res
(1998) - et al.
The highly reducing sugar 2-deoxy-d-ribose induces apoptosis in human fibroblasts by reduced glutathione depletion and cytoskeletal disruption
Biochem Biophys Res Commun
(1998) - et al.
Admission criteria for immunogerontological studies in manthe SENIEUR protocol
Mech Ageing Dev
(1984) - et al.
The CD95 system and the death of a lymphocyte
Semin Immunol
(1997)
A rapid and simple method for measuring thymocyte apoptosis by propidium iodide staining and flow cytometry
J Immunol Methods
Fas antigen expression in brains of patients with Alzheimer-type dementia
Brain Res
Susceptibility to apoptosis of T lymphocytes from elderly humans is associated with increased in vivo expression of functional Fas receptors
Mech Ageing Dev
The decrease of CD8-positive lymphocytes in Alzheimer’s disease
J Neurol Sci
Apoptosis and ageing
Mech Ageing Dev
Influence of specimen age and anticoagulant on flow cytometric evaluation of granulocyte oxidative burst generation
J Immunol Methods
Age-related tyrosine-specific protein phosphorylation defect in human T lymphocytes activated through CD3, CD4, CD8 or the IL-2 receptor
Mech Aging Dev
A rapid method for measuring apoptosis and dual-color immunofluorescence by single laser flow cytometry
J Immunol Methods
T lymphocyte subpopulations and activation markers correlate with severity of Alzheimer’s disease
Clin Immunol Immunopathol
Expression of c-fos, c-jun and jun B in peripheral blood lymphocytes from young and elderly adults
Mech Ageing Dev
The Bcl-2 oncoprotein functions as a pro-oxidant
J Biol Chem
Age-related decreases in IL-2 production by human T cells are associated with impaired activation of nuclear transcriptional factors AP-1 and NF-AT
Cell Immunol
Increased TNF-alpha-induced apoptosis in lymphocytes from aged humanschanges in TNF-alpha receptor expression and activation of caspases
J Immunol
Absolute peripheral blood lymphocyte count and subsequent mortality of elderly men. The Baltimore Longitudinal Study of Aging
J Am Geriatr Soc
Lymphocyte activation in health and disease
Crit Rev Immunol
Different pathways of apoptosis revealed by 2-chloro-adenosine and deoxy-d-ribose in mammalian astroglial cells
J Neurosci Res
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