Although the changes and heterogeneity in functional identity of human B cells during aging are well-described, the biochemical mechanisms underlying these changes are poorly understood. Our investigations demonstrate that stimulated B cells from substantial proportions of elderly subjects display impairments of early activation events not seen in B cells from young subjects. These include i) decreased G-O/G-1 progression, ii) reduced expression of early B cell activation molecules and iii) impaired cytosolic free calcium [Ca2+]i responses. Recent data directly demonstrate that stimulated B cells from approximately 50% of elderly subjects display impaired expression of tyrosine kinase (PTK) and protein kinase C (PKC) enzymatic activity not observed in B cells from young subjects. The overall objective of this revised proposal is to determine the biochemical mechanisms responsible for the differential expression of kinase activity observed with aging. This objective will help understand whether age-related imbalances can take place in selected biochemical events which affect the normal plasticity of early signaling and may modify the functional identity of human B cells.
The specific aims are 1) to quantitate the expression of PTK and PKC enzymatic activity in resting and stimulated B cells from elderly and young subjects, 2) to determine whether age-related changes take place in the levels and isozyme composition of PKC, 3) to investigate whether age-related alterations occur in the normal proteolytic conversion and degradation of PKC, and 4) to determine whether PKC inhibitors or PP1/PP2A phosphatases alter the expression of PKC enzymatic activity during aging. The methodologies for quantitating the alterations in PTK and PKC are enzymatic assays and immunoblots utilizing radiolabeled indicator systems operational in our laboratories. The design of the project now defines the age-related heterogeneity and impairments in the expression of kinase enzymatic activity among elderly humans using quantitative analyses and standard biostatistical procedures to assess the precision of measurements and to reach valid conclusions. The results from this project will provide new information about alterations in early biochemical events and signaling mechanisms which can occur in B cells from a substantial proportion of elderly humans. The work is intended to define the molecular mechanisms and biochemical events which can affect the plasticity and balance of early signaling events during aging. Defining age-related changes in the biochemical events and in the plasticity of early signals important for the functional identity of B cells will provide insights into the molecular basis of the immunobiology of aging. Furthermore, the definition of heterogeneity and of alterations in important biochemical events of human B cells during aging may serve to eventually understand the molecular basis for the heterogeneous effects of the aging process on the immune system of different elderly individuals.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG003763-09
Application #
2048777
Study Section
Immunological Sciences Study Section (IMS)
Project Start
1983-08-01
Project End
1996-12-31
Budget Start
1995-01-15
Budget End
1995-12-31
Support Year
9
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Ohio State University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
098987217
City
Columbus
State
OH
Country
United States
Zip Code
43210
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Karanfilov, C I; Liu, B; Fox, C C et al. (1999) Age-related defects in Th1 and Th2 cytokine production by human T cells can be dissociated from altered frequencies of CD45RA+ and CD45RO+ T cell subsets. Mech Ageing Dev 109:97-112
Whisler, R L; Chen, M; Liu, B et al. (1999) Age-related impairments in TCR/CD3 activation of ZAP-70 are associated with reduced tyrosine phosphorylations of zeta-chains and p59fyn/p56lck in human T cells. Mech Ageing Dev 111:49-66
Liu, B; Whisler, R L (1998) Transcriptional activation and redox regulation of the tumor necrosis factor-alpha promoter in human T cells: role of the CRE/kappa3 promoter region. J Interferon Cytokine Res 18:999-1007
Whisler, R L; Karanfilov, C I; Newhouse, Y G et al. (1998) Phosphorylation and coupling of zeta-chains to activated T-cell receptor (TCR)/CD3 complexes from peripheral blood T-cells of elderly humans. Mech Ageing Dev 105:115-35
Ginn-Pease, M E; Whisler, R L (1998) Redox signals and NF-kappaB activation in T cells. Free Radic Biol Med 25:346-61
Liu, B; Carle, K W; Whisler, R L (1997) Reductions in the activation of ERK and JNK are associated with decreased IL-2 production in T cells from elderly humans stimulated by the TCR/CD3 complex and costimulatory signals. Cell Immunol 182:79-88
Whisler, R L; Bagenstose, S E; Newhouse, Y G et al. (1997) Expression and catalytic activities of protein tyrosine kinases (PTKs) Fyn and Lck in peripheral blood T cells from elderly humans stimulated through the T cell receptor (TCR)/CD3 complex. Mech Ageing Dev 98:57-73
Whisler, R L; Chen, M; Beiqing, L et al. (1997) Impaired induction of c-fos/c-jun genes and of transcriptional regulatory proteins binding distinct c-fos/c-jun promoter elements in activated human T cells during aging. Cell Immunol 175:41-50
Whisler, R L; Beiqing, L; Chen, M (1996) 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 169:185-95

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