For the most part, decline in human immune function in advance age is due to decrease in T cell responses. The specific focus of this project is on determining the molecular and cellular alterations that lead to decreased in vitro proliferation of T cells from older subjects to mitogenic lectin and antibodies. Most of this decrease is due to diminished induction of synthesis of gene products that are required for entry into the cell cycle during the prereplicative interval, but early cytoplasmic intermediates that activate these genes are induced to the same level in young and old T cells. The hypothesis is that decreased expression of mitogen activated gene products is due to a specific defect in events at the nuclear level required for expression of newly synthesized gene products.
The Aims are: 1) To determine by Northern Blot analysis and other methods that reduced abundance of mRNA for mitogen activated gene products is responsible for diminished synthesis of these proteins in old T cells. The gene product analyzed will include Il-2 and the IL-2 receptor, and two proteins, HSP90 and p73, that are also part of the heat-shock response in lymphocytes. Induction of mRNA for HSP90 and p73 after heat-shock will be compared to induction following mitogen activation. 2) To determine the mechanisms responsible for reduced mRNA induction after heat-shock and mitogen activation. Transcriptional activation of specific genes will be determined by nuclear """"""""run-off"""""""" assays and mRNA half-life determined. The major test that aging affects mRNA processing in the nucleus will involve inhibition of mRNA splicing by severe heat-shock. 3) To determine the effect of aging on transport of proteins required for activation of DNA replication. Extracts from proliferating cells induce transport of high molecular weight proteins into quiescent nuclei leading to activation of DNA replication. The DNA replication response in lymphocyte nuclei isolated from older subjects is decreased and it will be determined if this is due to a defect in protein transport through the nuclear envelope.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
2R01AG002338-07A1
Application #
3114422
Study Section
Immunological Sciences Study Section (IMS)
Project Start
1985-09-01
Project End
1992-03-31
Budget Start
1989-04-01
Budget End
1990-03-31
Support Year
7
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Hansen, L K; O'Leary, J J; Skubitz, A P et al. (1995) Identification of a homologous heparin binding peptide sequence present in fibronectin and the 70 kDa family of heat-shock proteins. Biochim Biophys Acta 1252:135-45
Jackola, D R; O'Leary, J J (1992) Evidence for lymphocyte chemotaxis toward monocytes during PHA-induced aggregation in vitro. Cell Biophys 20:33-56
Hansen, L K; Houchins, J P; O'Leary, J J (1991) Differential regulation of HSC70, HSP70, HSP90 alpha, and HSP90 beta mRNA expression by mitogen activation and heat shock in human lymphocytes. Exp Cell Res 192:587-96
Jensen, T L; O'Leary, J J (1990) DNA synthesis in isolated resting nuclei: evidence for protease-dependent nonreplicative nucleotide incorporation. Exp Cell Res 190:85-90
Jackola, D R; O'Leary, J J (1989) Monocyte requirement for mitogen-induced aggregation of human peripheral mononuclear leukocytes in vitro. Exp Cell Res 184:119-30
Lustyik, G; O'Leary, J J (1989) Aging and the mobilization of intracellular calcium by phytohemagglutinin in human T cells. J Gerontol 44:B30-6
Hallgren, H M; Bergh, N; Rodysill, K J et al. (1988) Lymphocyte proliferative response to PHA and anti-CD3/Ti monoclonal antibodies, T cell surface marker expression, and serum IL-2 receptor levels as biomarkers of age and health. Mech Ageing Dev 43:175-85
Haire, R N; Peterson, M S; O'Leary, J J (1988) Mitogen activation induces the enhanced synthesis of two heat-shock proteins in human lymphocytes. J Cell Biol 106:883-91
Lustyik, G; Nagy, I (1988) Age dependent dehydration of postmitotic cells as measured by X-ray microanalysis of bulk specimens. Scanning Microsc 2:289-99
O'Leary, J J; Fox, R; Bergh, N et al. (1988) Expression of the human T cell antigen receptor complex in advanced age. Mech Ageing Dev 45:239-52

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