Glycogen synthase kinase 3 is a potential drug target for African trypanosomiasis therapy.
Development of a safe, effective, and inexpensive therapy for African trypanosomiasis is an urgent priority. In this study, we evaluated the validity of Trypanosoma brucei glycogen synthase kinase 3 (GSK-3) as a potential drug target. Interference with the RNA of either of two GSK-3 homologues in bloodstream-form T. brucei parasites led to growth arrest and altered parasite morphology, demonstrating their requirement for cell survival. Since the growth arrest after RNA interference appeared to be more profound for T. brucei GSK-3 "short" (Tb10.161.3140) than for T. brucei GSK-3 "long" (Tb927.7.2420), we focused on T. brucei GSK-3 short for further studies. T. brucei GSK-3 short with an N-terminal maltose-binding protein fusion was cloned, expressed, and purified in a functional form. The potency of a GSK-3-focused inhibitor library against the recombinant enzyme of T. brucei GSK-3 short, as well as bloodstream-form parasites, was evaluated with the aim of determining if compounds that inhibit enzyme activity could also block the parasites' growth and proliferation. Among the compounds active against the cell, there was an excellent correlation between activity inhibiting the T. brucei GSK-3 short enzyme and the inhibition of T. brucei growth. Thus, there is reasonable genetic and chemical validation of GSK-3 short as a drug target for T. brucei. Finally, selective inhibition may be required for therapy targeting the GSK-3 enzyme, and a molecular model of the T. brucei GSK-3 short enzyme suggests that compounds that selectively inhibit T. brucei GSK-3 short over the human GSK-3 enzymes can be found.
Ojo
Kayode K
KK
Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98195-7185, USA.
Gillespie
J Robert
JR
Riechers
Aaron J
AJ
Napuli
Alberto J
AJ
Verlinde
Christophe L M J
CL
Buckner
Frederick S
FS
Gelb
Michael H
MH
Domostoj
Mathias M
MM
Wells
Susan J
SJ
Scheer
Alexander
A
Wells
Timothy N C
TN
Van Voorhis
Wesley C
WC
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D017125:Genes, Protozoan; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D014346:Trypanosoma brucei brucei / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D014353:Trypanosomiasis, African / Q000188:drug therapy* / Q000469:parasitology*
D017931:DNA Primers; D016054:DNA, Protozoan; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D038362:Glycogen Synthase Kinase 3