title: Cytolysis by Ca-permeable transmembrane channels. Pore formation causes extensive DNA degradation and cell lysis.
abstract: This study investigates the effect of the purified membrane pore formers, staphylococcal alpha-toxin and CTL perforin, on target cell lysis as measured by 51Cr release and on nuclear damage as measured by DNA degradation and 125IUdR release. Both pore formers cause dose-dependent cell lysis, which is accompanied by DNA release. The ratio of DNA/Cr release depends on the nature of target cell and shows the same pattern as the ratio of release of the two markers reported for CTL-mediated lysis of the same targets. DNA degradation is dependent on the presence of intracellular Ca in the target cell and is totally blocked if Ca is chelated by Quin 2 intracellularly and EGTA extracellularly. DNA degradation, in addition, is inhibited by the lysosomotropic agents NH4Cl, chloroquine, and monensin. rTNF doubles the degree of DNA degradation mediated by alpha-toxin in 3-h assays. We conclude that pore formers alone can mediate DNA degradation. In addition, they may promote the uptake of other factors and thereby accelerate their time course of action. DNA degradation by pore formers requires active target participation in a pathway that is dependent on intracellular Ca and lysosomes. These aspects of target lysis resemble CTL- and NK cell-mediated cytolysis.
authors.affiliation: Department of Microbiology and Immunology, University of Miami, School of Medicine, Florida 33101.
authors.forename: A
authors.initials: A
authors.lastname: Hameed
authors.forename: K J
authors.initials: KJ
authors.lastname: Olsen
authors.forename: M K
authors.initials: MK
authors.lastname: Lee
authors.forename: M G
authors.initials: MG
authors.lastname: Lichtenheld
authors.forename: E R
authors.initials: ER
authors.lastname: Podack
mesh_terms: D000634:Aminoquinolines / Q000494:pharmacology; D000643:Ammonium Chloride / Q000494:pharmacology; D001427:Bacterial Toxins / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology*; D002460:Cell Line; D002463:Cell Membrane Permeability; D002470:Cell Survival; D002738:Chloroquine / Q000494:pharmacology; D002860:Chromium Radioisotopes; D004247:DNA / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D006460:Hemolysin Proteins; D006801:Humans; D007065:Idoxuridine / Q000378:metabolism; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000502:physiology; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000494:pharmacology; D008985:Monensin / Q000494:pharmacology; D009498:Neurotoxins; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D013210:Staphylococcus; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D000634:Aminoquinolines; D001427:Bacterial Toxins; D015220:Calcium Channels; D002860:Chromium Radioisotopes; D006460:Hemolysin Proteins; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009498:Neurotoxins; D052899:Pore Forming Cytotoxic Proteins; D014409:Tumor Necrosis Factor-alpha; C021091:staphylococcal alpha-toxin; D000643:Ammonium Chloride; D054353:Perforin; D004533:Egtazic Acid; D002738:Chloroquine; D004247:DNA; D008985:Monensin; D007065:Idoxuridine; C035739:Quin2; D002118:Calcium