Gene expression of RNAP II, JBP1 and JBP2 in Leishmania major exposed to antimonials, amphotericin B and paromomycin

Cutaneous leishmaniosis (CL) is treated with pentavalent antimony (SbV) as a first-line drug, while amphotericin B and paromomycin are potential alternatives in antimonial- resistant isolates. However, the mechanisms of drug resistance remain unclear. The present study analyses the gene expression of RNA polymerase II (RNAP II) and J-binding protein 1 (JBP1), and J-binding protein 2 (JBP2) in Leishmania major after exposure to drugs in vitro. L. major (MRHO/IR/75/ER) promastigotes were exposed to various concentrations of glucantime, paromomycin and amphotericin B for 72 hours. The RNA was then extracted and used for cDNA synthesis. The expressions of JBP1, JBP2 and RNAP II were analysed using SYBR Green real-time PCR. No change in JBP2 or RNAP II expression was associated with amphotericin B, but JBP1 expression decreased with increasing drug concentration. Paromomycin had no effect on JBP2 expression, but a 13.5-fold increase in JBP1 was observed at 100 μg/ml, and a decrease in RNAP II expression at 25 and 50 μg/ml. Exposure to glucantime resulted in 1.4-fold lower JBP1 expression at 5 μg/ml, and 333.33- to 500-fold lower RNAP II at concentrations of 5 to 15 μg/ml. As Base J synthesis requires both JBP1 and JBP2, RNAP II (encoding RNA polymerase II) could reduce expression. However, RNAP II was not expressed in all groups, indicating that the genes associated with drug resistance may be regulated in other ways.