Overexpression of Ubiquitin and Amino Acid Permease Genes in Association with Antimony Resistance in Leishmania tropica Field Isolates

Abstract

The mainstay therapy against leishmaniasis is still pentavalent antimonial drugs; however, the rate of antimony resistance is increasing in endemic regions such as Iran. Understanding the molecular basis of resistance to antimonials could be helpful to improve treatment strategies. This study aimed to recognize genes involved in antimony resistance of Leishmania tropica field isolates. Sensitive and resistant L. tropica parasites were isolated from anthroponotic cutaneous leishmaniasis patients and drug susceptibility of parasites to meglumine antimoniate (Glucantime®) was confirmed using in vitro assay. Then, complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) and real-time reverse transcriptase-PCR (RT-PCR) approaches were utilized on mRNAs from resistant and sensitive L. tropica isolates. We identified 2 known genes, ubiquitin implicated in protein degradation and amino acid permease (AAP3) involved in arginine uptake. Also, we identified 1 gene encoding hypothetical protein. Real-time RT-PCR revealed a significant upregulation of ubiquitin (2.54-fold), and AAP3 (2.86-fold) (P<0.05) in a resistant isolate compared to a sensitive one. Our results suggest that overexpression of ubiquitin and AAP3 could potentially implicated in natural antimony resistance.

Comparative transcriptomic analysis of antimony resistant and susceptible Leishmania infantum lines

“…Twenty transcripts that are 2.03 to 9.14-fold upregulated in the LiSbR line were assigned to this category, described as: ubiquitin, ubiquitin-transferase (HECT domain -homologous to the E6-AP carboxyl terminus and SPRY domain -SPla and the RYanodine Receptor), cullin protein (involved in ubiquitination through participation in multisubunit ubiquitin ligase complexes), zinc nger containing proteins and others (Table 2 and Additional le 1). Similar to our results, antimony-resistant L. tropica isolate also showed overexpression of ubiquitin [50]. These data suggest that increased levels of protein ubiquitination may contribute to degradation of oxidized proteins, protecting the parasite against oxidative stress from antimony.…”

Comparative transcriptomic analysis of antimony resistant and susceptible Leishmania infantum lines

“…Twenty transcripts that are 2.03 to 9.14-fold upregulated in the LiSbR line were assigned to this category, described as: ubiquitin, ubiquitin-transferase (HECT domain -homologous to the E6-AP carboxyl terminus and SPRY domain -SPla and the RYanodine Receptor), cullin protein (involved in ubiquitination through participation in multisubunit ubiquitin ligase complexes), zinc nger containing proteins and others (Table 2 and Additional le 1: Table S1). Similar to our results, antimony-resistant L. tropica isolate also showed overexpression of ubiquitin [50]. These data suggest that increased levels of protein ubiquitination may contribute to degradation of oxidized proteins, protecting the parasite against oxidative stress from antimony.…”

Comparative Transcriptomic Analysis of Antimony Resistant and Susceptible Leishmania Infantum Lines

“…Twenty transcripts that are 2.03 to 9.14-fold upregulated in the LiSbR line were assigned to this category, described as: ubiquitin, ubiquitin-transferase (HECT domainhomologous to the E6-AP carboxyl terminus and SPRY domain -SPla and the RYanodine Receptor), cullin protein (involved in ubiquitination through participation in multisubunit ubiquitin ligase complexes), Zinc nger containing proteins and others (Table 2 and Additional le 1). Similar to our results, antimonyresistant L. tropica isolate also showed overexpression of ubiquitin [76]. These data suggest that increased levels of protein ubiquitination may contribute to degradation of oxidized proteins, protecting the parasite against oxidative stress from antimony.…”