Isobenzofuranone derivative JVPH3, an inhibitor of L. donovani topoisomerase II, disrupts mitochondrial architecture in trypanosomatid parasites

Abstract

Kinetoplast DNA (kDNA) bearing unusual mitochondrion of trypanosomatid parasites offers a new paradigm in chemotherapy modality. Topoisomerase II of Leishmania donovani (LdTopII), a key enzyme associated with kDNA replication, is emerging as a potential drug target. However, mode of action of LdTopII targeted compounds in the parasites at sub-cellular level remains largely unknown. Previously, we reported that an isobenzofuranone derivative, namely 3,5-bis(4-chlorophenyl)-7-hydroxyisobenzofuran-1(3H)-one (JVPH3), targets LdTopII and induces apoptosis-like cell death in L. donovani. Here, we elucidate the phenotypic changes and the events occurring at sub-cellular level caused by JVPH3 in L. donovani. In addition, we have evaluated the cytotoxicity and ultrastructural alterations caused by JVPH3 in two brazilian trypanosomatid pathogens viz. L. amazonensis and Trypanosoma cruzi. Despite killing these parasites, JVPH3 caused significantly different phenotypes in L. donovani and L. amazonensis. More than 90% population of parasites showed altered morphology. Mitochondrion was a major target organelle subsequently causing kinetoplast network disorganization in Leishmania. Altered mitochondrial architecture was evident in 75–80% Leishmania population being investigated. Quantification of mitochondrial function using JC-1 fluorophore to measure a possible mitochondrial membrane depolarization further confirmed the mitochondrion as an essential target of the JVPH3 corroborating with the phenotype observed by electron microscopy. However, the impact of JVPH3 was lesser on T. cruzi than Leishmania. The molecule caused mitochondrial alteration in 40% population of the epimastigotes being investigated. To our knowledge, this is the first report to evaluate the proliferation pattern and ultrastructural alterations caused in Brazilian kinetoplastid pathogens by a synthetic LdTopII inhibitor previously established to have promising in vivo activity against Indian strain of L. donovani.

Anti-Leishmania major Properties of Nuphar lutea (Yellow Water Lily) Leaf Extracts and Purified 6,6′ Dihydroxythiobinupharidine (DTBN)

“…The toxicity of DTBN was also determined in this paper on Vero E6 cells [21]. These results are consistent with Topoisomerase II being a crucial enzyme associated with replication in parasites [33,34].…”

Twist and Turn—Topoisomerase Functions in Mitochondrial DNA Maintenance

“…The role of topoisomerases in organelle genome maintenance is perhaps best studied in trypanosomatid parasites such as Trypanosoma and Leishmania . In these organisms, the mitochondrial (kinetoplast) genome is organized in a complex network of interlocked circles, which requires both type I and II topoisomerase activity for maintenance [52,53]. The type I topoisomerase Top1A is required in the last phases of replication, while the type II Top2βmt re-attaches freshly replicated minicircles to the network and keeps the network intact [54].…”

Potential therapeutic targets shared between leishmaniasis and cancer

“…As aforementioned, similarly to TOP IB targeting agents, there are two groups of TOP II inhibitors depending of their mode of action, and some of them are even able to target both, type I and type II TOPs (Ray et al ., 1997 ). For instance, isobenzofuranone derivatives are capable to inhibit Leishmania TOP II linked to DNA (Mishra et al ., 2014 ; Chowdhury et al ., 2018 ), whereas protoberberine perform its effect by stabilizing TOP II–DNA cleavage complex (Marquis et al ., 2003 ). Mitonafide had demonstrated its activity on Leishmania nuclear and kinetoplast-TOP II (Slunt et al ., 1996 ).…”