Unique Leishmania mexicana clones secrete populations of extracellular vesicles with unique protein profile and
George Dong1, Noélie Douanne2, Christopher Fernandez-Prada2
1Infectious Diseases and Immunity in Global Health Program, Research Institute of McGill University Health Centre, Montréal, QC, Canada.
Abstract:
The study of extracellular vesicles has become an incredibly important field of study, but the inherent heterogeneity of these vesicles continues to make their study challenging. The genetic variability and well-documented protocols for the growth and vesicle isolation from Leishmania parasites provide a unique opportunity to compare the heterogeneity of different populations secreted by Leishmania clones. Leishmania mexicana was cultured on solid SDM agar plates and 8 clonal colonies were selected. The EVs collected from the liquid cultures of these 8 clones were assessed by NTA, TEM, and proteomic analysis. We found that all 8 clonal L. mexicana cultures were visually indistinguishable from each other and had similar growth rate, and these physical similarities extended to their EVs. However, proteomic analysis reveals that the EVs collected have unique protein profiles compared to each other and EVs isolated from a heterogeneous liquid culture of L. mexicana. We selected 3 clonal EVs for further mouse infection experiments and found that EVs from CL7 L. mexicana consistently caused reduced footpad swelling in C57BL6 mice footpads compared to EVs from CL1, CL8, and heterogenous L. mexicana. This trend was not observed when infecting Balb/C mice and C57BL6 with the parasites alone, with only CL1 L. mexicana causing significantly increased infection in Balb/c mice. Our results together show that EVs isolated from different clonal colonies of L. mexicana have distinct differences in protein cargo which can lead to varying outcomes on Leishmania infection. Further evaluation will be needed to determine the underlying mechanisms behind this and verify that differences observed in infectivity are directly caused by variations between our L. mexicana clones, especially genetic sequencing and immunoblotting to validate our results.
Insights
Extracellular vesicles (EVs) from different Leishmania clones show distinct protein profiles. These EV differences impact Leishmania infection outcomes in mice, highlighting the importance of EV heterogeneity in disease.
Area of Science:
- Parasitology
- Cell Biology
- Immunology
Background:
- Extracellular vesicles (EVs) are crucial in intercellular communication.
- EV heterogeneity poses challenges in understanding their biological roles.
- Leishmania parasites offer a model to study EV heterogeneity due to genetic variability.
Purpose of the Study:
- To investigate the heterogeneity of EVs secreted by different Leishmania mexicana clones.
- To compare the protein cargo and biological impact of EVs from clonal versus heterogeneous Leishmania populations.
- To assess the influence of Leishmania EVs on infection outcomes in mouse models.
Main Methods:
- Culture of 8 Leishmania mexicana clonal colonies.
- Isolation and characterization of EVs using Nanoparticle Tracking Analysis (NTA) and Transmission Electron Microscopy (TEM).
- Proteomic analysis of EVs.
- Mouse infection experiments with Leishmania EVs and parasites.
Main Results:
- Clonal Leishmania mexicana cultures and their EVs were physically similar but proteomically distinct.
- EVs from different clones exhibited unique protein profiles compared to heterogeneous cultures.
- Leishmania EVs influenced infection severity in mice, with CL7 EVs reducing swelling in C57BL6 mice.
- Parasite infection alone showed different trends, with CL1 increasing infection in Balb/c mice.
Conclusions:
- EVs from distinct Leishmania mexicana clones possess unique protein cargo.
- These protein cargo differences can lead to varied outcomes in Leishmania infection.
- Further research, including genetic sequencing, is needed to elucidate the mechanisms driving these observed differences.
