Downregulation of Calcineurin Gene Is Associated with Glucan¬time® Resiatance in Leishmania infantum

Pentavalent antimonials are the first line drugs for the treatment of leishmaniasis. Unresponsiveness of Leishmania spp. to antimonial drugs is a serious problem in some endemic areas. Investigations on molecular mechanisms involved in drug resistance are essential for monitoring and managing of the disease. Calcineu­rin is an essential protein phosphatase for number of signal transduction pathways in eukaryotic cells and it has a mediated role in apoptosis. This study aimed to determine of biomarker(s) in Glucantime® resiatance strain of L. infan­tum. We used cDNA amplified fragment length polymorphism (cDNA-AFLP) and real time-RT PCR assays to compare gene expression profiles at the mRNA levels in resistant and susceptible L. infantum field isolates. The cDNA-AFLP results showed downlegulation of calcineurin in resis­tant isolate in comparison with susceptible one. Significant downregulation of calcineu­rin (0.42 fold) (P<0.05) was found in resistant isolate compared to suscepti­ble one by Real time-RT PCR. This is the first report of calcineurin implication in Glucantime® drug resistance of field (natural) isolate of L. infantum. Downregulation of calcineurin could protect parasites from antimonial-induced apoptosis.