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. 1997 Oct;191(Pt 3):355–365. doi: 10.1046/j.1469-7580.1997.19130355.x

Modulation of dye-coupling and proliferation in cultured rat thymic epithelium by factors involved in thymulin secretion

G M HEAD 1 , R MENTLEIN 2 , A KRANZ 2 , J E G DOWNING 1 , M D KENDALL 3 ,✉
PMCID: PMC1467693  PMID: 9418992

Abstract

Cultures of rat thymic epithelium were used to measure the effect of thymulin secretagogues on dye-coupling and proliferation. Dye-coupling was assessed after the injection of lucifer yellow dextran which cannot permeate the connexin pore of gap junctions and the smaller, permeant cascade blue. In addition to gap junctional communication, larger intercellular bridges were demonstrated by the transfer of lucifer yellow dextran between cells. The extent of intercellular communication was found to be influenced by both cell density and the number of passages. In control cultures, intercellular communication was reduced in cell groups of low (<20 cells/group) or high cell densities (>100 cells/group) compared with groups of 20–60 cells. The highest coupling indices were found in subcultures 20–30. Taking these factors into account, significant decreases in coupling index were observed after pretreatment of test cultures with factors known to influence the secretion of thymulin (5 U/ml interleukin 1 (α and β), 1 μ M progesterone, 1 μ M oestrogen, 1 μ M testosterone, 1 ng/ml adrenocorticotropic hormone, 100 nm rat growth hormone) but 7.5 ng/ml thymulin had no effect on dye-coupling. The nonspecific gap junction uncoupler, octanol, abolished dye-coupling. Cellular proliferation, as measured by the uptake of tritiated thymidine, showed that the same factors that reduced coupling also increased proliferation. None of these factors affected the number of multinucleate cells present, except interleukin-1β which caused a significant reduction in the average number of nuclei per cell. Thus rat thymic epithelium in vitro provides a model for the study of the direct action of factors on cells of the thymic microenvironment.

Keywords: Gap junctions, intercellular bridges

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Selected References

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  1. Alves L. A., Campos de Carvalho A. C., Cirne Lima E. O., Rocha e Souza C. M., Dardenne M., Spray D. C., Savino W. Functional gap junctions in thymic epithelial cells are formed by connexin 43. Eur J Immunol. 1995 Feb;25(2):431–437. doi: 10.1002/eji.1830250219. [DOI] [PubMed] [Google Scholar]
  2. Alves L. A., de Carvalho A. C., Parreira-Martins L., Dardenne M., Savino W. Intrathymic gap junction-mediated communication. Adv Exp Med Biol. 1994;355:155–158. doi: 10.1007/978-1-4615-2492-2_26. [DOI] [PubMed] [Google Scholar]
  3. Bach J., Bardenne M., Pleau J., Rosa J. Biochemical characterisation of a serum thymic factor. Nature. 1977 Mar 3;266(5597):55–57. doi: 10.1038/266055a0. [DOI] [PubMed] [Google Scholar]
  4. Bordigoni P., Béné M. C., Faure G., Donner M., Janot C., Dardenne M., Duheille J., Olive D. Allogeneic bone marrow transplantation in man: in vitro activity of FTS-Zn on T-cell markers and functions. Br J Haematol. 1984 Dec;58(4):661–669. doi: 10.1111/j.1365-2141.1984.tb06113.x. [DOI] [PubMed] [Google Scholar]
  5. Combettes L., Tran D., Tordjmann T., Laurent M., Berthon B., Claret M. Ca(2+)-mobilizing hormones induce sequentially ordered Ca2+ signals in multicellular systems of rat hepatocytes. Biochem J. 1994 Dec 1;304(Pt 2):585–594. doi: 10.1042/bj3040585. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Cook J. E., Becker D. L. Gap junctions in the vertebrate retina. Microsc Res Tech. 1995 Aug 1;31(5):408–419. doi: 10.1002/jemt.1070310510. [DOI] [PubMed] [Google Scholar]
  7. Coto J. A., Hadden E. M., Sauro M., Zorn N., Hadden J. W. Interleukin 1 regulates secretion of zinc-thymulin by human thymic epithelial cells and its action on T-lymphocyte proliferation and nuclear protein kinase C. Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7752–7756. doi: 10.1073/pnas.89.16.7752. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Dardenne M., Savino W. Control of thymus physiology by peptidic hormones and neuropeptides. Immunol Today. 1994 Nov;15(11):518–523. doi: 10.1016/0167-5699(94)90207-0. [DOI] [PubMed] [Google Scholar]
  9. Dokhelar M. C., Tursz T., Dardenne M., Bach J. F. Effect of a synthetic thymic factor (facteur thymique serique) on natural killer cell activity in humans. Int J Immunopharmacol. 1983;5(4):277–282. doi: 10.1016/0192-0561(83)90029-2. [DOI] [PubMed] [Google Scholar]
  10. Fabris N., Muzzioli M., Mocchegiani E. Recovery of age-dependent immunological deterioration in Balb/c mice by short-term treatment with L-thyroxine. Mech Ageing Dev. 1982 Apr;18(4):327–338. doi: 10.1016/0047-6374(82)90036-7. [DOI] [PubMed] [Google Scholar]
  11. Hadden J. W., Galy A., Chen H., Hadden E. M. A pituitary factor induces thymic epithelial cell proliferation in vitro. Brain Behav Immun. 1989 Jun;3(2):149–159. doi: 10.1016/0889-1591(89)90015-9. [DOI] [PubMed] [Google Scholar]
  12. Hossain M. D., Evers A. S. Volatile anesthetic-induced efflux of calcium from IP3-gated stores in clonal (GH3) pituitary cells. Anesthesiology. 1994 Jun;80(6):1379–28A. [PubMed] [Google Scholar]
  13. Jambon B., Montagne P., Bene M. C., Brayer M. P., Faure G., Duheille J. Immunohistologic localization of "facteur thymique serique" (FTS) in human thymic epithelium. J Immunol. 1981 Nov;127(5):2055–2059. [PubMed] [Google Scholar]
  14. Kaiserlian D., Dardenne M. Studies on the mechanisms of the inhibitory effects of serum thymic factor on murine allograft immunity. Cell Immunol. 1982 Jan 15;66(2):360–371. doi: 10.1016/0008-8749(82)90186-1. [DOI] [PubMed] [Google Scholar]
  15. Kendall M. D. Functional anatomy of the thymic microenvironment. J Anat. 1991 Aug;177:1–29. [PMC free article] [PubMed] [Google Scholar]
  16. Kendall M. D. The outer and inner thymus cortex is a functional syncytium. Cell Biol Int Rep. 1985 Jan;9(1):3–3. doi: 10.1016/0309-1651(85)90135-3. [DOI] [PubMed] [Google Scholar]
  17. Kendall M. D. The syncytial nature of epithelial cells in the thymic cortex. J Anat. 1986 Aug;147:95–106. [PMC free article] [PubMed] [Google Scholar]
  18. Krenács T., Rosendaal M. Immunohistological detection of gap junctions in human lymphoid tissue: connexin43 in follicular dendritic and lymphoendothelial cells. J Histochem Cytochem. 1995 Nov;43(11):1125–1137. doi: 10.1177/43.11.7560895. [DOI] [PubMed] [Google Scholar]
  19. Kumar N. M., Gilula N. B. Molecular biology and genetics of gap junction channels. Semin Cell Biol. 1992 Feb;3(1):3–16. doi: 10.1016/s1043-4682(10)80003-0. [DOI] [PubMed] [Google Scholar]
  20. Kurz B., von Gaudecker B., Krisch B., Mentlein R. Rat thymic epithelial cells in vitro and in situ: characterization by immunocytochemistry and morphology. Cell Tissue Res. 1996 Feb;283(2):221–229. doi: 10.1007/s004410050533. [DOI] [PubMed] [Google Scholar]
  21. Loewenstein W. R. Junctional intercellular communication: the cell-to-cell membrane channel. Physiol Rev. 1981 Oct;61(4):829–913. doi: 10.1152/physrev.1981.61.4.829. [DOI] [PubMed] [Google Scholar]
  22. Meda P., Pepper M. S., Traub O., Willecke K., Gros D., Beyer E., Nicholson B., Paul D., Orci L. Differential expression of gap junction connexins in endocrine and exocrine glands. Endocrinology. 1993 Nov;133(5):2371–2378. doi: 10.1210/endo.133.5.8404689. [DOI] [PubMed] [Google Scholar]
  23. Millington G., Buckingham J. C. Thymic peptides and neuroendocrine-immune communication. J Endocrinol. 1992 May;133(2):163–168. doi: 10.1677/joe.0.1330163. [DOI] [PubMed] [Google Scholar]
  24. Monier J. C., Dardenne M., Pléau J. M., Schmitt D., Deschaux P., Bach J. F. Characterization of facteur thymique sérique (FTS) in the thymus. I. Fixation of anti-FTS antibodies on thymic reticulo-epithelial cells. Clin Exp Immunol. 1980 Dec;42(3):470–476. [PMC free article] [PubMed] [Google Scholar]
  25. Munari-Silem Y., Lebrethon M. C., Morand I., Rousset B., Saez J. M. Gap junction-mediated cell-to-cell communication in bovine and human adrenal cells. A process whereby cells increase their responsiveness to physiological corticotropin concentrations. J Clin Invest. 1995 Apr;95(4):1429–1439. doi: 10.1172/JCI117813. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Muzzioli M., Mocchegiani E., Bressani N., Bevilacqua P., Fabris N. In vitro restoration by thymulin of NK activity of cells from old mice. Int J Immunopharmacol. 1992 Jan;14(1):57–61. doi: 10.1016/0192-0561(92)90105-t. [DOI] [PubMed] [Google Scholar]
  27. Pappas C. A., Rioult M. G., Ransom B. R. Octanol, a gap junction uncoupling agent, changes intracellular [H+] in rat astrocytes. Glia. 1996 Jan;16(1):7–15. doi: 10.1002/(SICI)1098-1136(199601)16:1<7::AID-GLIA2>3.0.CO;2-2. [DOI] [PubMed] [Google Scholar]
  28. Robinson D. N., Cooley L. Stable intercellular bridges in development: the cytoskeleton lining the tunnel. Trends Cell Biol. 1996 Dec;6(12):474–479. doi: 10.1016/0962-8924(96)84945-2. [DOI] [PubMed] [Google Scholar]
  29. Rosendaal M., Green C. R., Rahman A., Morgan D. Up-regulation of the connexin43+ gap junction network in haemopoietic tissue before the growth of stem cells. J Cell Sci. 1994 Jan;107(Pt 1):29–37. doi: 10.1242/jcs.107.1.29. [DOI] [PubMed] [Google Scholar]
  30. Russell L. D., Goh J. C., Rashed R. M., Vogl A. W. The consequences of actin disruption at Sertoli ectoplasmic specialization sites facing spermatids after in vivo exposure of rat testis to cytochalasin D. Biol Reprod. 1988 Aug;39(1):105–118. doi: 10.1095/biolreprod39.1.105. [DOI] [PubMed] [Google Scholar]
  31. Russell L. D., Vogl A. W., Weber J. E. Actin localization in male germ cell intercellular bridges in the rat and ground squirrel and disruption of bridges by cytochalasin D. Am J Anat. 1987 Sep;180(1):25–40. doi: 10.1002/aja.1001800103. [DOI] [PubMed] [Google Scholar]
  32. Santos-Sacchi J. Isolated supporting cells from the organ of Corti: some whole cell electrical characteristics and estimates of gap junctional conductance. Hear Res. 1991 Mar;52(1):89–98. doi: 10.1016/0378-5955(91)90190-k. [DOI] [PubMed] [Google Scholar]
  33. Savino W., Dardenne M., Bach J. F. Thymic hormone containing cells. III. Evidence for a feed-back regulation of the secretion of the serum thymic factor (FTS) by thymic epithelial cells. Clin Exp Immunol. 1983 Apr;52(1):7–12. [PMC free article] [PubMed] [Google Scholar]
  34. Savino W., Dardenne M., Papiernik M., Bach J. F. Thymic hormone-containing cells. Characterization and localization of serum thymic factor in young mouse thymus studied by monoclonal antibodies. J Exp Med. 1982 Aug 1;156(2):628–633. doi: 10.1084/jem.156.2.628. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Savino W., Dardenne M. Thymic hormone-containing cells VI. Immunohistologic evidence for the simultaneous presence of thymulin, thymopoietin and thymosin alpha 1 in normal and pathological human thymuses. Eur J Immunol. 1984 Nov;14(11):987–991. doi: 10.1002/eji.1830141105. [DOI] [PubMed] [Google Scholar]
  36. Schmitt D., Monier J. C., Dardenne M., Pleau J. M., Bach J. F. Location of FTS (facteur thymique sérique) in the thymus of normal and auto-immune mice. Thymus. 1982 Jul;4(4):221–231. [PubMed] [Google Scholar]
  37. Trosko J. E., Madhukar B. V., Chang C. C. Endogenous and exogenous modulation of gap junctional intercellular communication: toxicological and pharmacological implications. Life Sci. 1993;53(1):1–19. doi: 10.1016/0024-3205(93)90606-4. [DOI] [PubMed] [Google Scholar]
  38. Witkin J. W., O'Sullivan H., Silverman A. J. Novel associations among gonadotropin-releasing hormone neurons. Endocrinology. 1995 Oct;136(10):4323–4330. doi: 10.1210/endo.136.10.7664651. [DOI] [PubMed] [Google Scholar]
  39. Zhang M., Thorgeirsson S. S. Modulation of connexins during differentiation of oval cells into hepatocytes. Exp Cell Res. 1994 Jul;213(1):37–42. doi: 10.1006/excr.1994.1170. [DOI] [PubMed] [Google Scholar]
  40. van de Wijngaert F. P., Kendall M. D., Schuurman H. J., Rademakers L. H., Kater L. Heterogeneity of epithelial cells in the human thymus. An ultrastructural study. Cell Tissue Res. 1984;237(2):227–237. doi: 10.1007/BF00217140. [DOI] [PubMed] [Google Scholar]

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