Quantitative proteomic analysis to determine differentially expressed proteins in axenic amastigotes of Leishmania tropica and Leishmania major

Abstract

Cutaneous leishmaniasis is commonly caused by Leishmania major and Leishmania tropica. In the present study, the differential expression of proteins was identified in the amastigote-like forms of L. tropica and L. major in Iranian isolates. Initially, the samples were cultured and identified using PCR-RFLP technique. The Leishmania isolates were then grown in host-free (axenic) culture and prepared to amastigote-like forms, followed by the extraction of their proteins. To identify significant differentially expressed proteins (DEPs) of two types of Leishmania, the label-free quantitative proteomic technique was used based on sequential window acquisition of all theoretical fragment ion spectra mass spectrometry. A total of 51 up/down-DEPs (fold change >2 and p-value <.05) were identified between the axenic amastigote forms of L. major and L. tropica. Of these, 34 and 17 proteins were up-regulated in L. major and L. tropica, respectively. Several enriched GO terms were identified via biological process analyses for DEPs; furthermore, the metabolic process and translation were disclosed as top category in the up-regulated proteins of both L. major and L. tropica species. Also, the KEGG analysis revealed carbon metabolism and metabolic pathways term as the top pathways in the proteins up-regulated in L. major and L. tropica, respectively. Taken together, the numerous novel DEPs identified between the studied species could help fully understand the molecular mechanisms of pathogenesis and provide potential drug targets and vaccine candidates.