P-glycoprotein A Gene Expression in Glucantime-Resistant and Sensitive Leishmania major (MRHO/IR/75/ER)

Leishmaniasis is a parasitic disease caused by different species of Leishma­nia parasites with a wide range of clinical manifestations. Antimonial com­pounds such as meglumine antimoniate (glucantime) are the first line drugs for the treat­ment of leishmaniasis. However, according to reports of the drug resistance of parasites, the efficacy of antimonial compounds is low. The ATP-binding cassette (ABC) proteins are present in all organisms and mediate the transport of vital elements through biological membranes. One of the important mechanisms of resistance in Leishma­nia parasites is the overexpression of ABC efflux pumps. P-glycoprotein A (pgpA) is a related gene for ABC transporter in Leishmania species. The aim of this study was to compare the pgpA expression in laboratory-induced resistant L. major (MRHO/IR/75/ER) and sensitive parasites. RNA extraction of promastigotes of sensitive and resistant clones was per­formed and total RNA was reverse transcribed. The real-time quantitative polymerase chain reaction (PCR) was used to assess RNA expression profiles and the expression levels were calculated using 2-ΔCt method. The mean expression level of pgpA mRNA was 2.70 ± 0.51 in in sensitive Leishmania clone and 6.08 ± 1.50 in resistant Leishmania clone (P = 0.021). The expression of pgpA gene in resistant strains of L. major was almost fivefold higher than those in susceptible strains. Therefore, this can be used in field isolates, i.e. overexpression of the gene can prove resistance in wild type field isolates.