Proteomic analysis reveals differentially expressed proteins in macrophages infected with Leishmania amazonensis or Leishmania major.

CBA macrophages effectively control Leishmania major infection, yet are permissive to Leishmania amazonensis. Employing a transcriptomic approach, we previously showed the up-regulation of the genes involved in the classical pathway of macrophage activation in resistant mice. However, microarray analyses do not evaluate changes in gene expression that occur after translation. To circumvent this analytical limitation, we employed a proteomics approach to increase our understanding of the modulations that occur during infection and identify novel targets for the control of Leishmania infection. To identify proteins whose expression changes in CBA macrophages infected with L. major or L. amazonensis, protein extracts were obtained and digested and the peptides were characterized using multi-dimensional liquid chromatography coupled with tandem mass spectrometry analyses. A total of 162 proteins were selected as potentially modulated. Using biological network analyses, these proteins were classified as primarily involved in cellular metabolism and grouped into cellular development biological networks. This study is the first to use a proteomics approach to describe the protein modulations involved in cellular metabolism during the initial events of Leishmania-macrophage interaction. Based on these findings, we hypothesize that these differentially expressed proteins likely play a pivotal role in determining the course of infection.