Leishmania-infected macrophages release extracellular vesicles that can promote lesion development
Anna Gioseffi1, Tim Hamerly2, Kha Van1
1Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA.
Abstract:
Leishmania donovani infection of macrophages results in quantitative and qualitative changes in the protein profile of extracellular vesicles (EVs) released by the infected host cells. We confirmed mass spectrometry results orthogonally by performing Western blots for several Leishmania-infected macrophage-enriched EVs (LieEVs) molecules. Several host cell proteins in LieEVs have been implicated in promoting vascular changes in other systems. We also identified 59 parasite-derived proteins in LieEVs, including a putative L. donovani homolog of mammalian vasohibins (LdVash), which in mammals promotes angiogenesis. We developed a transgenic parasite that expressed an endogenously tagged LdVash/mNeonGreen (mNG) and confirmed that LdVash/mNG is indeed expressed in infected macrophages and in LieEVs. We further observed that LieEVs induce endothelial cells to release angiogenesis promoting mediators including IL-8, G-CSF/CSF-3, and VEGF-A. In addition, LieEVs induce epithelial cell migration and tube formation by endothelial cells in surrogate angiogenesis assays. Taken together, these studies show that Leishmania infection alters the composition of EVs from infected cells and suggest that LieEVs may play a role in the promotion of vascularization of Leishmania infections.
Insights
Leishmania donovani infection alters extracellular vesicles (EVs) released by macrophages. These altered EVs promote blood vessel growth, suggesting a role in Leishmania infection vascularization.
Area of Science:
- Parasitology
- Cell Biology
- Molecular Biology
Background:
- Leishmania donovani infects macrophages, altering host cell functions.
- Extracellular vesicles (EVs) mediate intercellular communication and can be modified by infection.
- Vascular changes are associated with various pathological conditions.
Purpose of the Study:
- To investigate the proteomic changes in EVs from Leishmania-infected macrophages.
- To identify parasite-derived proteins within EVs that may influence host cell behavior.
- To determine the role of these EVs in promoting angiogenesis.
Main Methods:
- Mass spectrometry and Western blotting to analyze EV protein composition.
- Development of transgenic parasites for protein expression tracking.
- In vitro assays using endothelial and epithelial cells to assess angiogenesis-related functions.
Main Results:
- Leishmania infection significantly altered the protein content of macrophage-derived EVs.
- Identified parasite-derived proteins, including a vasohibin homolog (LdVash), within EVs.
- EVs from infected macrophages induced endothelial cells to release pro-angiogenic factors and promoted endothelial cell migration and tube formation.
Conclusions:
- Leishmania infection modifies macrophage EVs, enriching them with specific host and parasite proteins.
- These altered EVs (LieEVs) possess pro-angiogenic properties.
- LieEVs may contribute to the vascularization of Leishmania infections, potentially impacting disease progression.
