Antileishmanial Mechanism of Diamidines Involves Targeting Kinetoplasts.
Leishmaniasis is a disease caused by pathogenic Leishmania parasites; current treatments are toxic and expensive, and drug resistance has emerged. While pentamidine, a diamidine-type compound, is one of the treatments, its antileishmanial mechanism of action has not been investigated in depth. Here we tested several diamidines, including pentamidine and its analog DB75, against Leishmania donovani and elucidated their antileishmanial mechanisms. We identified three promising new antileishmanial diamidine compounds with 50% effective concentrations (EC50s) of 3.2, 3.4, and 4.5 μM, while pentamidine and DB75 exhibited EC50s of 1.46 and 20 μM, respectively. The most potent antileishmanial inhibitor, compound 1, showed strong DNA binding properties, with a shift in the melting temperature (ΔTm) of 24.2°C, whereas pentamidine had a ΔTmvalue of 2.1°C, and DB75 had a ΔTmvalue of 7.7°C. Additionally, DB75 localized in L. donovani kinetoplast DNA (kDNA) and mitochondria but not in nuclear DNA (nDNA). For 2 new diamidines, strong localization signals were observed in kDNA at 1 μM, and at higher concentrations, the signals also appeared in nuclei. All tested diamidines showed selective and dose-dependent inhibition of kDNA, but not nDNA, replication, likely by inhibiting L. donovani topoisomerase IB. Overall, these results suggest that diamidine antileishmanial compounds exert activity by accumulating toward and blocking replication of parasite kDNA.
Leishmania Research Laboratory, Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, Republic of Korea.|Interdisciplinary Programs of Functional Genomics, Yonsei University, Seoul, Republic of Korea.
Gyongseon
G
Yang
Leishmania Research Laboratory, Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, Republic of Korea.
Gahee
G
Choi
Leishmania Research Laboratory, Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, Republic of Korea joohwan.no@ip-korea.org.
Joo Hwan
JH
No
D000578:Amidines / Q000737:chemistry / Q000494:pharmacology*; D001550:Benzamidines / Q000737:chemistry / Q000494:pharmacology; D004261:DNA Replication / Q000187:drug effects; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism; D018105:DNA, Kinetoplast / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005453:Fluorescence; D007893:Leishmania donovani / Q000187:drug effects* / Q000254:growth & development; D058990:Molecular Targeted Therapy; D010419:Pentamidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D059005:Topoisomerase II Inhibitors / Q000737:chemistry / Q000494:pharmacology; D014344:Trypanocidal Agents / Q000737:chemistry / Q000494:pharmacology*
D000578:Amidines; D001550:Benzamidines; D018105:DNA, Kinetoplast; D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D015800:Protozoan Proteins; D059005:Topoisomerase II Inhibitors; D014344:Trypanocidal Agents; D010419:Pentamidine; C033286:furamidine; D004250:DNA Topoisomerases, Type II