The long term goal of the proposed research is to understand the action of adrenal steroid hormones (glucocorticoids) on lymphocytes and the immune system in general. We will continue to investigate in detail the glucocorticoid induced cellular mechanisms which ultimately lead to lymphocyte death and thereby suppressed immune function. The thymic lymphocyte of the adrenalectomized rat will be the focus of our attention. The cells are well suited for these investigations because they are abundant, uniform in cell cycle stage. uniform in state of differentiation, responsive to glucocorticoids in vitro and in vivo and a well studied model for adrenal steroid action. Three seminal observations concerning glucocorticoid induced lymphocytolysis have been made during the past granting period. They are: 1) Glucocorticoid induced lymphocyte cell death is preceeded by DNA degradation; 2) Glucocorticoid induced DNA degradation is not random, implying specificity; 3) A nuclear glucocorticoid """"""""induced"""""""" nuclease activity has been identified. Based on these observations, we wish to propose the following hypothesis: Glucocorticoids induce or activate a deoxyribonuclease which selectively alters the integrity of genomic DNA and causes the cells to die. To test this hypothesis, we propose the following Specific Aims: 1) To evaluate whether glucocorticoid induced """"""""breaks"""""""" in DNA occur in transcribed or non-transcribed genomic sequences; 2) To purify to homogeneity the glucocorticoid """"""""induced"""""""" nuclease and test its specificity in vitro; 3) To clone the glucocorticoid """"""""induced"""""""" nuclease gene and evaluate its role in glucocorticoid induced cell death by transfection experiments; 4) Lastly, to evaluate via selective cell sorting the development of glucocorticoid resistance during the differentiation of rat thymic lymphocytes to mature T cells. Together, these studies should test the proposed hypothesis and provide data on the molecular basis for glucocorticoid induced lymphoid cell death.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK032078-06
Application #
3230542
Study Section
Endocrinology Study Section (END)
Project Start
1983-04-01
Project End
1991-03-31
Budget Start
1988-04-01
Budget End
1989-03-31
Support Year
6
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
King, K L; Cidlowski, J A (1995) Cell cycle and apoptosis: common pathways to life and death. J Cell Biochem 58:175-80
Montague, J W; Cidlowski, J A (1995) Glucocorticoid-induced death of immune cells: mechanisms of action. Curr Top Microbiol Immunol 200:51-65
Montague, J W; Gaido, M L; Frye, C et al. (1994) A calcium-dependent nuclease from apoptotic rat thymocytes is homologous with cyclophilin. Recombinant cyclophilins A, B, and C have nuclease activity. J Biol Chem 269:18877-80
Caron-Leslie, L A; Evans, R B; Cidlowski, J A (1994) Bcl-2 inhibits glucocorticoid-induced apoptosis but only partially blocks calcium ionophore or cycloheximide-regulated apoptosis in S49 cells. FASEB J 8:639-45
Hughes Jr, F M; Cidlowski, J A (1994) Regulation of apoptosis in S49 cells. J Steroid Biochem Mol Biol 49:303-10
Schwartzman, R A; Cidlowski, J A (1994) Glucocorticoid-induced apoptosis of lymphoid cells. Int Arch Allergy Immunol 105:347-54
Schwartzman, R A; Cidlowski, J A (1993) Apoptosis: the biochemistry and molecular biology of programmed cell death. Endocr Rev 14:133-51
Schwartzman, R A; Cidlowski, J A (1993) Mechanism of tissue-specific induction of internucleosomal deoxyribonucleic acid cleavage activity and apoptosis by glucocorticoids. Endocrinology 133:591-9
Caron-Leslie, L M; Schwartzman, R A; Gaido, M L et al. (1991) Identification and characterization of glucocorticoid-regulated nuclease(s) in lymphoid cells undergoing apoptosis. J Steroid Biochem Mol Biol 40:661-71
Gaido, M L; Cidlowski, J A (1991) Identification, purification, and characterization of a calcium-dependent endonuclease (NUC18) from apoptotic rat thymocytes. NUC18 is not histone H2B. J Biol Chem 266:18580-5

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