RESEARCH ARTICLES CURRENT SCIENCE, VOL. 120, NO. 6, 25 MARCH 2021 1040 *For correspondence. (e-mail: nayebalia@sbmu.ac.ir) Prediction of potential drug targets for cutaneous leishmaniasis by Leishmania major and Leishmania tropica: a quantitative proteomics and bioinformatics approach Nasrin Amiri-Dashatan 1 , Marzieh Ashrafmansouri 2 , Mostafa Rezaei-Tavirani 1 , Mehdi Koushki 3 and Nayebali Ahmadi 1, * 1 Proteomics Research Center, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2 Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran 3 Department of Clinical Biochemistry, Zanjan University of Medical Sciences, Zanjan, Iran Leishmania spp. cause life-threatening infectious dis- eases which affect universal health. Novel treatments for leishmaniasis are crucially needed since those available are limited by emerging drug-resistant spe- cies, low efficacy and side effects. In this study, we have employed a quantitative shotgun proteomics and bioinformatics method to identify differentially ex- pressed proteins (DEPs) between Leishmania major and Leishmania tropica and to detect novel potential drug targets for cutaneous leishmaniasis, which may aid in the future drug discovery process. A total of 57 proteins were differentially expressed between the studied species. Based on KEGG pathway analysis, the more upregulated proteins in L. major are clearly re- lated to proteasome and metabolic pathways. In L. tropica, most of the upregulated proteins are related to the metabolic pathway and carbon metabolism. According to gene ontology analysis based on biologi- cal process, the upregulated proteins mainly partici- pated in translation and carbohydrate metabolism in L. tropica and L. major respectively. We have con- structed a protein–protein interaction network that is common for the two species. We detected the top 10 potential targets for drug design by topology analysis of the protein network. Additional in vivo studies are needed to confirm these targets. We have identified several new DEPs between the species which would help in the understanding of pathogenesis mecha- nisms, and offer potential drug targets and vaccine candidates. Analysis of the predicted protein network provides a catalogue of key proteins, which can be considered in future studies to be validated as drug- gable targets against cutaneous leishmaniasis. Keywords: Cutaneous leishmaniasis, Leishmania tro- pica, Leishmania major, protein interaction network, quantitative proteomics. LEISHMANIA spp. cause leishmaniasis, a vector-borne dis- ease. Clinical manifestation of the disease includes simple, self-limiting, cutaneous lesions, severe mucocu- taneous and fatal visceral disease 1 . Leishmaniasis is classified as one of the neglected tropical diseases by the World Health Organization because 98 tropical and sub- tropical countries are known to be endemic to this disease, with an estimated risk to 350 million people, prevalence of 12 million infected subjects and 0.9 –1.6 million new patients each year worldwide 2 . Iran is one of the endemic regions to cutaneous leishmaniasis (CL), which is mostly caused by Leishmania major and Leish- mania tropica 3,4 . Leishmania is a digenetic organism which shifts between the flagellated, free-living promas- tigotes (procyclic and metacyclic) form and a non-motile and intracellular amastigote form. Given the technical difficulty in generating large quantities of amastigotes, we used logarithmic-phase procyclic promastigotes in this study. Due to lack of effective drugs and vaccines against leishmaniasis, it remains a major health issue worldwide. The present anti-leishmanial treatment relies on pentavalent antimony (including Pentostam and Glu- cantime) therapy. This classical treatment is largely un- successful due to toxicity, Leishmania species diversity, and differences in their susceptibility to drugs and vary- ing sensitivity of host immune response. Severe side effects and the emergence of drug-resistant species are major problems in many endemic regions 5,6 . Thus, new and safe compounds are necessary. Over the past few years, proteomics study based on mass spectrometry (MS) has expanded its role in almost all diverse research fields of science. As drug discovery is an inherently com- plex and expensive process, new emerging technologies such as proteomics integrated with bioinformatics can accelerate this process. The drug discovery process has many stages in which proteomics plays a major role in target identification as the first step in the process. Exten- sive research has provided information on Leishmania