Metabolite profiling of experimental cutaneous leishmaniasis lesions demonstrates significant perturbations in tissue phospholipids
Each year 700,000 to 1.2 million new cases of cutaneous leishmaniasis (CL) are reported and yet CL remains one of thirteen diseases classified as neglected tropical diseases (NTDs). Leishmania major is one of several different species of that same genus that can cause CL. Current CL treatments are limited by adverse effects and rising resistance. Studying disease metabolism at the site of infection can lead to new drug targets. In this study, samples were collected from mice infected in the ear and footpad with L. major and analyzed by untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS). Significant differences in overall metabolite profiles were noted in the ear at the site of the lesion. Interestingly, lesion-adjacent, macroscopically healthy sites also showed alterations in specific metabolites, including select phosphocholines (PCs). Host-derived PCs in the lower m/z range (m/z 200-799) showed an increase with infection in the ear at the lesion site, while those in the higher m/z range (m/z 800-899) were decreased with infection at the lesion site. Overall, our results expanded our understanding of the mechanisms of CL pathogenesis through the host metabolism and may lead to new curative measures against infection with Leishmania. Author summaryCutaneous leishmaniasis (CL) is one of thirteen neglected tropical diseases in the world today. It is an infectious disease with a wide distribution spanning five continents, with increasing distribution expected due to climate change. CL manifests as skin lesions and ulcers that are disabling and stigmatized. With the current treatment options being limited, studying host-pathogen metabolism can uncover mechanisms of disease pathogenesis that may lead to new curative measures against infection. In this paper we used untargeted metabolomics to address molecular-level changes occurring in vivo in experimental skin lesions of Leishmania major. Distinct global metabolic profiles were observed. Total phosphocholines (PCs) and those in the lower m/z ranges were significantly higher at the site of the skin lesion in the ear. In addition, specific PCs as well as PCs of varied m/z ranges were also affected at healthy-appearing lesion-adjacent sites, indicating that infection-induced metabolic perturbations are not restricted to the lesion site. Ultimately, these results provide essential clues to the metabolic pathways affected by CL.