title: Improvement of deficient natural killer activity and delayed bactericidal activity by a thiol proteinase inhibitor, E-64-d, in leukocytes from Chediak-Higashi syndrome patients in vitro.
abstract: We previously reported that administration of a potent calpain inhibitor, E-64-d, which protects protein kinase C (PKC) from proteolysis, in a mouse model of Chediak-Higashi syndrome (CHS) (beige mice), decreases its susceptibility to Staphylococcus aureus infection. In the present study, we examined the in vitro effect of E-64-d on both deficient natural killer (NK) and delayed bactericidal activities of leukocytes from six CHS patients. Our results showed that pretreatment of peripheral blood mononuclear cells (PBMCs) obtained from CHS patients with E-64-d (1 microg/ml) significantly enhanced NK activity against K562 cells. The delayed bactericidal activity of polymorphonuclear cells (PMNs) against S. aureus also showed marked improvement. This was recovered to almost normal levels when PMNs were pretreated with E-64-d (1 microg/ml). On the other hand, the same concentration of E-64-d did not affect either the NK or bactericidal activity of normal controls. In addition, we confirmed that following E-64-d treatment, the abnormal down-regulation of PKC activity after concanavalin A (Con A) stimulation was eliminated in PBMCs obtained from CHS patients. To examine whether PKC is involved in the NK cell-mediated cytolysis and bactericidal activity of PMNs, two potent PKC inhibitors, chelerythrin and GO6976, were used. We found that chelerythrin inhibits NK activity of normal PBMCs in a dose-dependent manner, and GO6976 inhibits NK activity at doses that inhibit Ca(2+)-dependent PKC isozymes. These inhibitors also suppressed the bactericidal activity of PMNs against S. aureus. Taken together, our findings suggested that E-64-d improved the compromised NK and bactericidal activity of leukocytes from CHS patients by reversing the down-regulation of PKC activity.
authors.affiliation: Department of Human Science, Faculty of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan. ftanabe@yamanashi.ac.jp
authors.forename: Fuminori
authors.initials: F
authors.lastname: Tanabe
authors.forename: Hirotake
authors.initials: H
authors.lastname: Kasai
authors.forename: Limin
authors.initials: L
authors.lastname: He
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kin
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujikado
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kumamoto
authors.forename: Toshiro
authors.initials: T
authors.lastname: Hara
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Iwata
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ito
mesh_terms: D053119:Benzophenanthridines / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D002609:Chediak-Higashi Syndrome / Q000150:complications / Q000276:immunology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D007930:Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
chemical_list: D053119:Benzophenanthridines; D002227:Carbazoles; D015853:Cysteine Proteinase Inhibitors; D047428:Protein Kinase Inhibitors; C081021:Go 6976; C016299:chelerythrine; D011493:Protein Kinase C; D007930:Leucine; C024974:E 64