Glycosomal ABC transporter 3 (GAT3) is associated with antileishmanial drug susceptibility in Leishmania infantum.
TL;DR
It is demonstrated that GAT3 is a non-essential glycosomal ABC transporter that contributes to antileishmanial drug susceptibility in L. infantum and the association between GAT3 deletion and reduced expression of AQP1 and MT suggests a previously unrecognized link between glycosomal transport processes and pathways involved in drug uptake and resistance.
Abstract
Leishmaniasis remains a major public health challenge due to the limited therapeutic options available and the increasing emergence of drug-resistant parasites. Membrane transporters play essential roles in parasite physiology and drug susceptibility; however, the biological functions of glycosomal ATP-binding cassette (ABC) transporters remain poorly understood in Leishmania. In this study, we investigated the role of glycosomal ABC transporter 3 (GAT3) in Leishmania infantum by generating knockout mutants using CRISPR-Cas9-mediated gene editing. Successful deletion of GAT3 was confirmed in two independent knockout clones, which were subsequently characterized with respect to growth, drug susceptibility, oxidative stress tolerance, and infectivity in THP-1-derived macrophages. GAT3 deletion resulted in a modest reduction in promastigote proliferation. Notably, GAT3-knockout promastigotes displayed a 2.3-fold increase in resistance to trivalent antimony and a 3.4-fold increase in resistance to miltefosine compared with control parasites. This phenotype was accompanied by decreased transcript levels of aquaglyceroporin 1 (AQP1) and the miltefosine transporter (MT), two membrane transporters known to mediate the uptake of these antileishmanial drugs. In contrast, GAT3 deletion did not alter susceptibility to amphotericin B or tolerance to hydrogen peroxide-induced oxidative stress. Furthermore, loss of GAT3 had no detectable effect on macrophage infectivity. Collectively, our findings demonstrate that GAT3 is a non-essential glycosomal ABC transporter that contributes to antileishmanial drug susceptibility in L. infantum. The association between GAT3 deletion and reduced expression of AQP1 and MT suggests a previously unrecognized link between glycosomal transport processes and pathways involved in drug uptake and resistance, expanding current knowledge of glycosomal transporter function in Leishmania.
