Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1989 Jul 15;261(2):395–400. doi: 10.1042/bj2610395

Lipocortin-independent effect of dexamethasone on phospholipase activity in a thymic epithelial cell line.

A Piltch 1, L Sun 1, R A Fava 1, J Hayashi 1
PMCID: PMC1138839  PMID: 2528346

Abstract

In the cloned rat thymic endocrine epithelial cell line TEA3A1, treatment with dexamethasone leads to decreased levels of prostaglandin E2, prostaglandin F2 alpha, and thromboxane B2. Dexamethasone treatment also leads to a decrease of both calcium-dependent and calcium-independent phospholipase A2 activity measured in a cell-free assay. Dexamethasone-treated cells also have increased levels of lipocortin-I, a putative modulator of phospholipase A2 activity. The property of calcium-dependent binding of lipocortin to the particulate fraction was used to prepare cytosolic and particulate subcellular fractions which contained phospholiphase A2 activity but no lipocortin-I. Dexamethasone decreased phospholipase A2 activity in both cytosolic and particulate fractions even in the absence of lipocortin, suggesting the presence of a lipocortin-independent mechanism.

Full text

PDF
395

Images in this article

398Fig. 2.
on p.398
398Fig. 3.
on p.398

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aarsman A. J., Mynbeek G., van den Bosch H., Rothhut B., Prieur B., Comera C., Jordan L., Russo-Marie F. Lipocortin inhibition of extracellular and intracellular phospholipases A2 is substrate concentration dependent. FEBS Lett. 1987 Jul 13;219(1):176–180. doi: 10.1016/0014-5793(87)81212-7. [DOI] [PubMed] [Google Scholar]
  2. Campbell W. B., Ojeda S. R. Measurement of prostaglandins by radioimmunoassay. Methods Enzymol. 1987;141:323–341. doi: 10.1016/0076-6879(87)41080-x. [DOI] [PubMed] [Google Scholar]
  3. Chouaib S., Welte K., Mertelsmann R., Dupont B. Prostaglandin E2 acts at two distinct pathways of T lymphocyte activation: inhibition of interleukin 2 production and down-regulation of transferrin receptor expression. J Immunol. 1985 Aug;135(2):1172–1179. [PubMed] [Google Scholar]
  4. Davidson F. F., Dennis E. A., Powell M., Glenney J. R., Jr Inhibition of phospholipase A2 by "lipocortins" and calpactins. An effect of binding to substrate phospholipids. J Biol Chem. 1987 Feb 5;262(4):1698–1705. [PubMed] [Google Scholar]
  5. Farrar W. L., Humes J. L. The role of arachidonic acid metabolism in the activities of interleukin 1 and 2. J Immunol. 1985 Aug;135(2):1153–1159. [PubMed] [Google Scholar]
  6. Fava R. A., Cohen S. Isolation of a calcium-dependent 35-kilodalton substrate for the epidermal growth factor receptor/kinase from A-431 cells. J Biol Chem. 1984 Feb 25;259(4):2636–2645. [PubMed] [Google Scholar]
  7. Fava R. A., Piltch A. S. Histological distribution of the 35-KD protein substrate of the epidermal growth factor receptor/kinase in thymus. J Histochem Cytochem. 1987 Nov;35(11):1309–1315. doi: 10.1177/35.11.3309047. [DOI] [PubMed] [Google Scholar]
  8. Hayari Y., Kukulansky T., Globerson A. Regulation of thymocyte proliferative response by macrophage-derived prostaglandin E2 and interleukin 1. Eur J Immunol. 1985 Jan;15(1):43–47. doi: 10.1002/eji.1830150109. [DOI] [PubMed] [Google Scholar]
  9. Hirata F., Notsu Y., Yamada R., Ishihara Y., Wano Y., Kunos I., Kunos G. Isolation and characterization of lipocortin (lipomodulin). Agents Actions. 1986 Jan;17(3-4):263–266. doi: 10.1007/BF01982617. [DOI] [PubMed] [Google Scholar]
  10. Homo F., Russo-Marie F., Papiernik M. Prostaglandin secretion by human thymic epithelium: in vitro effects of steroids. Prostaglandins. 1981 Sep;22(3):377–385. doi: 10.1016/0090-6980(81)90100-3. [DOI] [PubMed] [Google Scholar]
  11. Horrobin D. F., Morgan R. O., Karmali R. A., Ally A. I., Manku M. S., Karmazyn M., Cunnane S. C. Thymic changes in muscular dystrophy and evidence for an abnormality related to prostaglandin synthesis or action. Ann N Y Acad Sci. 1979;317:534–549. doi: 10.1111/j.1749-6632.1979.tb56574.x. [DOI] [PubMed] [Google Scholar]
  12. Knudsen P. J., Dinarello C. A., Strom T. B. Prostaglandins posttranscriptionally inhibit monocyte expression of interleukin 1 activity by increasing intracellular cyclic adenosine monophosphate. J Immunol. 1986 Nov 15;137(10):3189–3194. [PubMed] [Google Scholar]
  13. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  14. Markwell M. A., Haas S. M., Bieber L. L., Tolbert N. E. A modification of the Lowry procedure to simplify protein determination in membrane and lipoprotein samples. Anal Biochem. 1978 Jun 15;87(1):206–210. doi: 10.1016/0003-2697(78)90586-9. [DOI] [PubMed] [Google Scholar]
  15. McKeehan W. L., Adams P. S., Rosser M. P. Direct mitogenic effects of insulin, epidermal growth factor, glucocorticoid, cholera toxin, unknown pituitary factors and possibly prolactin, but not androgen, on normal rat prostate epithelial cells in serum-free, primary cell culture. Cancer Res. 1984 May;44(5):1998–2010. [PubMed] [Google Scholar]
  16. Piltch A., Naylor P., Hayashi J. A cloned rat thymic epithelial cell line established from serum-free selective culture. In Vitro Cell Dev Biol. 1988 Apr;24(4):289–293. doi: 10.1007/BF02628829. [DOI] [PubMed] [Google Scholar]
  17. Sawyer S. T., Cohen S. Epidermal growth factor stimulates the phosphorylation of the calcium-dependent 35,000-dalton substrate in intact A-431 cells. J Biol Chem. 1985 Jul 15;260(14):8233–8236. [PubMed] [Google Scholar]
  18. Schlaepfer D. D., Haigler H. T. Characterization of Ca2+-dependent phospholipid binding and phosphorylation of lipocortin I. J Biol Chem. 1987 May 15;262(14):6931–6937. [PubMed] [Google Scholar]
  19. Shakir K. M. Phospholipase A2 activity of post-heparin plasma: a rapid and sensitive assay and partial characterization. Anal Biochem. 1981 Jun;114(1):64–70. doi: 10.1016/0003-2697(81)90452-8. [DOI] [PubMed] [Google Scholar]
  20. Shipman P. M., Schmidt R. R., Chepenik K. P. Relation between arachidonic acid metabolism and development of thymocytes in fetal thymic organ cultures. J Immunol. 1988 Apr 15;140(8):2714–2720. [PubMed] [Google Scholar]
  21. Singh U., Owen J. J. Studies on the effect of various agents on the maturation of thymus stem cells. Eur J Immunol. 1975 Apr;5(4):286–288. doi: 10.1002/eji.1830050414. [DOI] [PubMed] [Google Scholar]
  22. Towbin H., Staehelin T., Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4350–4354. doi: 10.1073/pnas.76.9.4350. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Zurier R. B. Prostaglandins, immune responses, and murine lupus. Arthritis Rheum. 1982 Jul;25(7):804–809. doi: 10.1002/art.1780250718. [DOI] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES