Bisamidine Derivatives as Candidates for Tegumentary Leishmaniasis Therapy: Phenotypic Screening in Infection of Macrophages and Mechanistic Insights with Dual RNA-seq

Leishmania braziliensis is the primary
causative agent of American tegumentary leishmaniasis (ATL), a critical
parasitic tropical neglected disease. The chemotherapeutic arsenal
has limited efficacy and significant toxic effects that lead to an
urgent need to develop new medicines. Using the “drug repurposing”
approach, histone-modifying enzyme inhibitors have been the subject
of developing new drugs against neglected parasitic diseases. In this
work, furamidine, a known diphenyl furan inhibitor of human Protein
Arginine Methyltransferase (PRMT), along with a library of 31 developed
analogues, was tested for leishmanicidal activity against L. braziliensis in the in vitro infection of macrophage
assay. The most active and selective leishmanicidal analogue, BSF2
(EC50 of 0.64 μM (95% CI: 0.56–0.72), SI of
17.36), was further investigated by dual RNA-seq at 0.16 μM
BSF2. The dual-transcriptome detected only 10 genes with significant
differential expression (FDR ≤10%) in L. braziliensis related to ubiquitination, chromatin remodeling, and peroxisomal
membrane transport pathways, following BSF2 treatment of infected
macrophages. In addition, BSF2 had a significant effect (FDR ≤5%)
on the expression of 577 genes in the infected macrophages, including
the downregulation of TNF, IL-17, NF-κB, and Toll-like receptor
pathways. This work opens new venues for developing new chemotherapy
for leishmaniasis based on BSF2 or derivatives and highlights the
dual transcriptome as a valuable phenotypic assay tool to investigate
host–parasite interactions for antileishmanial drug discovery.