title: Pharmacological assessment defines Leishmania donovani casein kinase 1 as a drug target and reveals important functions in parasite viability and intracellular infection.
abstract: Protein kinase inhibitors have emerged as new drugs in various therapeutic areas, including leishmaniasis, an important parasitic disease. Members of the Leishmania casein kinase 1 (CK1) family represent promising therapeutic targets. Leishmania casein kinase 1 isoform 2 (CK1.2) has been identified as an exokinase capable of phosphorylating host proteins, thus exerting a potential immune-suppressive action on infected host cells. Moreover, its inhibition reduces promastigote growth. Despite these important properties, its requirement for intracellular infection and its chemical validation as a therapeutic target in the disease-relevant amastigote stage remain to be established. In this study, we used a multidisciplinary approach combining bioinformatics, biochemical, and pharmacological analyses with a macrophage infection assay to characterize and define Leishmania CK1.2 as a valid drug target. We show that recombinant and transgenic Leishmania CK1.2 (i) can phosphorylate CK1-specific substrates, (ii) is sensitive to temperature, and (iii) is susceptible to CK1-specific inhibitors. CK1.2 is constitutively expressed at both the promastigote insect stage and the vertebrate amastigote stage. We further demonstrated that reduction of CK1 activity by specific inhibitors, such as D4476, blocks promastigote growth, strongly compromises axenic amastigote viability, and decreases the number of intracellular Leishmania donovani and L. amazonensis amastigotes in infected macrophages. These results underline the potential role of CK1 kinases in intracellular survival. The identification of differences in structure and inhibition profiles compared to those of mammalian CK1 kinases opens new opportunities for Leishmania CK1.2 antileishmanial drug development. Our report provides the first chemical validation of Leishmania CK1 protein kinases, required for amastigote intracellular survival, as therapeutic targets.
authors.affiliation: Institut Pasteur and CNRS URA2581, Unité de Parasitologie Moléculaire et Signalisation, Paris, France.
authors.forename: Najma
authors.initials: N
authors.lastname: Rachidi
authors.forename: Jean François
authors.initials: JF
authors.lastname: Taly
authors.forename: Emilie
authors.initials: E
authors.lastname: Durieu
authors.forename: Olivier
authors.initials: O
authors.lastname: Leclercq
authors.forename: Nathalie
authors.initials: N
authors.lastname: Aulner
authors.forename: Eric
authors.initials: E
authors.lastname: Prina
authors.forename: Pascale
authors.initials: P
authors.lastname: Pescher
authors.forename: Cedric
authors.initials: C
authors.lastname: Notredame
authors.forename: Laurent
authors.initials: L
authors.lastname: Meijer
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Späth
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D047389:Casein Kinase I / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D017124:Conserved Sequence / Q000235:genetics; D006224:Cricetinae / Q000469:parasitology; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D007893:Leishmania donovani / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D007898:Leishmaniasis, Visceral / Q000188:drug therapy / Q000469:parasitology; D008264:Macrophages / Q000469:parasitology; D008810:Mice, Inbred C57BL; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000494:pharmacology; D016415:Sequence Alignment; D014344:Trypanocidal Agents / Q000494:pharmacology
chemical_list: C493177:4-(4-(2,3-dihydrobenzo(1,4)dioxin-6-yl)-5-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; C411652:IC 261; D007093:Imidazoles; D007211:Indoles; D007546:Isoquinolines; D014344:Trypanocidal Agents; C058815:N-(2-aminoethyl)-5-chloroisoquinoline-8-sulfonamide; D010696:Phloroglucinol; D047389:Casein Kinase I