title: Two Novel Calcium-Dependent Protein Kinase 1 Inhibitors Interfere with Vertical Transmission in Mice Infected with Neospora caninum Tachyzoites.
abstract: We present the effects of two novel bumped kinase inhibitors, BKI-1517 and BKI-1553, againstNeospora caninumtachyzoitesin vitroand in experimentally infected pregnant mice. These compounds inhibited tachyzoite proliferation of a transgenic beta-galactosidase reporter strain cultured in human foreskin fibroblasts with 50% inhibitory concentrations (IC50s) of 0.05 ± 0.03 and 0.18 ± 0.03 μM, respectively. As assessed by an alamarBlue assay, fibroblast IC50s were above 20 μM; however, morphological changes occurred in cultures treated with >5 μM BKI-1517 after prolonged exposure (>6 days). Treatment of intracellular tachyzoites with 5 μM BKI-1553 for 6 days inhibited endodyogeny by interfering with the separation of newly formed zoites from a larger multinucleated parasite mass. In contrast, parasites treated with 5 μM BKI-1517 did not form large complexes and showed much more evidence of cell death. However, after a treatment duration of 10 daysin vitro, both compounds failed to completely prevent the regrowth of parasites from culture. BALB/c mice experimentally infected withN. caninumSpain7 (Nc-Spain7) and then treated during 6 days with BKI-1517 or BKI-1553 at different dosages showed a significant reduction of the cerebral parasite load. However, fertility was impaired by BKI-1517 when applied at 50 mg/kg of body weight/day. At 20 mg/kg/day, BKI-1517 significantly inhibited the vertical transmission ofN. caninumto pups and increased the rate of survival of offspring. BKI-1553 was less detrimental to fertility and also provided significant but clearly less pronounced protection of dams and offspring. These results demonstrate that, when judiciously applied, this compound class protects offspring from vertical transmission and disease.
authors.affiliation: Institute of Parasitology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Joachim
authors.initials: J
authors.lastname: Müller
authors.affiliation: Institute of Parasitology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Adriana
authors.initials: A
authors.lastname: Aguado-Martínez
authors.affiliation: Institute of Parasitology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Vreni
authors.initials: V
authors.lastname: Balmer
authors.affiliation: Department of Chemistry, University of Washington, Seattle, Washington, USA.
authors.forename: Dustin J
authors.initials: DJ
authors.lastname: Maly
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, Washington, USA.
authors.forename: Erkang
authors.initials: E
authors.lastname: Fan
authors.affiliation: SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain.
authors.forename: Luis-Miguel
authors.initials: LM
authors.lastname: Ortega-Mora
authors.affiliation: Center for Emerging and Reemerging Infectious Diseases, Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA.
authors.forename: Kayode K
authors.initials: KK
authors.lastname: Ojo
authors.affiliation: Center for Emerging and Reemerging Infectious Diseases, Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA.
authors.forename: Wesley C
authors.initials: WC
authors.lastname: Van Voorhis
authors.affiliation: Institute of Parasitology, Vetsuisse Faculty, University of Bern, Bern, Switzerland andrew.hemphill@vetsuisse.unibe.ch.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hemphill
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000469:parasitology; D049109:Cell Proliferation / Q000187:drug effects; D003048:Coccidiosis / Q000188:drug therapy* / Q000469:parasitology / Q000635:transmission; D003049:Coccidiostats / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D005298:Fertility / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000469:parasitology; D015870:Gene Expression; D017930:Genes, Reporter; D006801:Humans; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D008018:Life Cycle Stages / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D018688:Neospora / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D010078:Oxazines; D011247:Pregnancy; D061251:Primary Cell Culture; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011720:Pyrazoles / Q000737:chemistry / Q000494:pharmacology*; D011743:Pyrimidines / Q000737:chemistry / Q000494:pharmacology*; D011804:Quinolines / Q000737:chemistry / Q000494:pharmacology*; D014966:Xanthenes; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: C000623215:BK-1517; C000623214:BKI-1553; D003049:Coccidiostats; D010078:Oxazines; D047428:Protein Kinase Inhibitors; D015800:Protozoan Proteins; D011720:Pyrazoles; D011743:Pyrimidines; D011804:Quinolines; D014966:Xanthenes; C005843:resazurin; D011494:Protein Kinases; D001616:beta-Galactosidase
keywords: Neospora caninum; apicomplexan parasites; bumped kinase inhibitor; calcium-dependent protein kinase; chemotherapy; fertility; pregnant mouse model; vertical transmission