Selective Alteration of Cytokeratin Intermediate Filament by Cyclosporine A is a Lethal Toxicity in PTK2 Cell Cultures

  • Lawrence A. Vernetti
  • A. Jay Gandolfi
  • Raymond B. Nagle
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 283)


The cytoplasm of eukaryotic cells contain a series of three filamentous structures, microtubules, microfilaments, and intermediate filaments that are termed the cytoskeleton. Cytokeratin, one type of intermediate filament, has no known physiological function, yet, can comprise up to 30% of the total cytoplasmic protein content. As there are no selective toxins to cytokeratins, it is not known if alterations to these hydrophobic filaments is a lethal event. Cyclosporine A, a novel hydrophobic immunosuppressant compound used to prevent allograft rejection, may show a selective toxicity to the cytokeratin filaments. This effect is seen in PtK2 cell cultures as a single large perinuclear aggregate of collapsed cytokeratin filaments (5 mM, 72 hr). Microtubules and microfilaments are not affected in PtK2 cell cultures (5 mM, 72 hr). Increased LDH levels into cell culturing media occur soon after cyclosporine exposure to PtK2 cell cultures (5 mM, 2 hr). Cytokeratin filaments show no changes at 12 hr exposure but show thickening, decreased plasma membrane attachments and some peri-nuclear ring formations at 24 hr (5 mM, 24 hr). Cyclosporine G, an analog of cyclosporine A, does not exhibit the cytokeratin filament collapse (5 mM, 72 hr). The effect of cyclosporine A on DNA binding protein (Mr 64 kd), believed to be a nuclear scaffolding protein related to intermediate filaments, exhibited an early invagination and folding of the nuclear membrane (5 mM, 4 hr). Due to a hydrophobic bonding potential between cyclosporine A and cytokeratin and cytokeratin-like intermediate filaments, cyclosporin A may be a selective cytokeratin toxin. Alteration of the cytokeratin filaments in PtK2 cell cultures may be a lethal event.


Intermediate Filament Nuclear Matrix Amide Hydrogen PtK2 Cell Selective Alteration 
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  1. Achtstatter, T., Hatzfeld, M., Quinlan, R.A., Parmelee, D.C., Franke, W.W. (1986). Separation of cytokeratin polypeptides by gel electrophoretic and chromatographic techniques and their identification by immunoblotting. Methods in Enzymology 134, 355–371.CrossRefGoogle Scholar
  2. Barak, L.S., Yocum, R.R. (1981). 7-Nitrobenz-2-oxa-1,3- diazole (NBD)-phallacidin; synthesis of a fluorescent actin probe. Analyt. Biochem. 31, 110–117.Google Scholar
  3. Blose, S.H., Meltzer, D.I. (1981). Visualization of the 10-nm filament vimentin rings in vascular endothelial cells in situ: close resemblence to vimentin cytoskeletons found in monolayer in vitro. Exp. Cell. Res. 135, 299–300.CrossRefGoogle Scholar
  4. Chen, W. (1988). Yeast plasmid protein is a karyoskeleton component. EMBO J. 7, 4323–4328.Google Scholar
  5. Colambani, P.M., Donnenberg, A.D., Robb, A., Hess, A.D. (1987). Use of T lymphocyte clones to analyze cyclosporin binding. Transplan. Proc. 17, 1413–1419.Google Scholar
  6. Cress, A.E., Kurath, K. (1988). Identification of attachment proteins for DNA in Chinese hamster ovary cells. J. Biol. Chem. 263, 19678–19684.PubMedGoogle Scholar
  7. DeRobertis, E., Partington, G.A., Longthorne, R.F., Gurdon, J.B. (1977). Somatic nuclei in amphibian oocytes: evidence for selective gene expression. J. Embryo’. Ex. Morph. 50, 199–214.Google Scholar
  8. Gown, A.M. (1986). Immunocytochemical analysis of the cellular composition of human atherosclerotic lesions. Am. J. Path. 125, 191–207.PubMedGoogle Scholar
  9. Inselmann, G., Blank, M., Bauman, K. (1988). Cyclosporine A induced lipid peroxidation in microsomes and effect on active and passive glucose transport by brush border membrane vesicle of rat kidney. Re. Comm. Chem. Pathol. Pharmacol. 62, 207–220.Google Scholar
  10. Jackson, D.A., Cook, P.R. (1988). Visualization of a filamentous nucleoskeleton with a 23 nm axial repeat. EMBO J. 7, 3677–3687.Google Scholar
  11. Moll, R. et al. (1982). The catalog of human cytokeratins: patterns and expression in normal epithelia, tumors, and cultured cells. Cell 31, 11–24.PubMedCrossRefGoogle Scholar
  12. Nagle, R.B. (1988). Intermediate filaments: a review of basic biology. Am. J. Surg. Path. 12, 4–16.Google Scholar
  13. Nagle, R.B., Bocker, W., Davis, J.R., Heid, H.W., Kaufman, M., Lucas, D.O., Jarasch, E.D. (1988). Characterization of breast carcinoma by two monoclonal antibodies distinguishing myoepithelial from luminal epithelial cells. J. Hist. CytoChem. 34, 869–881.CrossRefGoogle Scholar
  14. O’Farrell, P.Z. et al. (1977). High resolution two dimensional electrophoresis of basic as well as acidic protein. Cell 12, 1133–1142.PubMedCrossRefGoogle Scholar
  15. Takahashi, N., Hayano, T., Susuki, M. (1989). Petidyl-prolyl cis-trans isomerase is the cyclosporin A-binding protein cyclophilin. Nature 337, 473–475.PubMedCrossRefGoogle Scholar
  16. Walker, R.J., Lazzaro, V.A., Duggin, G.G., Horvath, J.S., Tiller, D.J. (1989). Cyclosporin A inhibits protein kinase C activity: a contributing mechanism in the development of nephrotoxicity. Biochem. Biophys. Re. Comm. 160, 409–415.Google Scholar
  17. Weir, D.M. (1979). Handbook of Experimental Immunology, Blackwell Scientific Publications, England 3rd edition.Google Scholar

Copyright information

© Plenum Press, New York 1991

Authors and Affiliations

  • Lawrence A. Vernetti
    • 1
  • A. Jay Gandolfi
    • 1
  • Raymond B. Nagle
    • 2
  1. 1.Department of AnesthesiologyUniversity of ArizonaTucsonUSA
  2. 2.Department of PathologyUniversity of ArizonaTucsonUSA

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