title: Cytotoxic activity and probable apoptotic effect of Sph2, a sphigomyelinase hemolysin from Leptospira interrogans strain Lai.
abstract: Our previous work confirmed that Sph2/LA1029 was a sphigomyelinase-like hemolyisn of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai. Characteristics of both hemolytic and cytotoxic activities of Sph2 were reported in this paper. Sph2 was a heat-labile neutral hemolysin and had similar hemolytic behavior as the typical sphingomyelinase C of Staphylococcus aureus upon sheep erythrocytes. The cytotoxic activity of Sph2 was shown in mammalian cells such as BALB/C mouse lymphocytes and macrophages, as well as human L-02 liver cells. Transmission electron microscopic observation showed that the Sph2 treated BALB/C mouse lymphocytes were swollen and ruptured with membrane breakage. They also demonstrated condensed chromatin as a high-density area. Cytoskeleton changes were observed via fluorescence confocal microscope in Sph2 treated BALB/C mouse lymphocytes and macrophages, where both cytokine IL-1beta and IL-6 were induced. In addition, typical apoptotic morphological features were observed in Sph2 treated L-02 cells via transmission electron microscope and the percentage of apoptotic cells did increase after the Sph2 treatment detected by flow cytometry. Therefore, Sph2 was likely an apoptosis-inducing factor of human L-02 liver cells.
authors.affiliation: School of Life Science and Biopharmaceuticals, Shenyang Pharmaceutical University Shenyang, China.
authors.forename: Yi-Xuan
authors.initials: YX
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Geng
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Yang
authors.forename: Xiao-Kui
authors.initials: XK
authors.lastname: Guo
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Zhao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001426:Bacterial Proteins / Q000633:toxicity*; D003599:Cytoskeleton / Q000378:metabolism; D004912:Erythrocytes / Q000473:pathology*; D005434:Flow Cytometry; D006460:Hemolysin Proteins / Q000633:toxicity*; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D007921:Leptospira interrogans / Q000201:enzymology*; D008099:Liver / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D008214:Lymphocytes / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D008264:Macrophages / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D051379:Mice; D008807:Mice, Inbred BALB C; D012756:Sheep
chemical_list: D001426:Bacterial Proteins; D006460:Hemolysin Proteins; D053583:Interleukin-1beta; D015850:Interleukin-6; C443499:SphH protein, Leptospira interrogans