Back to Search
Start Over
Uncovering Novel Immuno-metabolic Profiles in Cutaneous Leishmaniasis:From Vaccine Development to Analgesic Mechanisms
- Publication Year :
- 2022
-
Abstract
- Leishmaniasis is a neglected protozoan disease affecting over 12 million people globally. Cutaneous leishmaniasis (CL) is the most common form, characterized by chronic skin lesions. Currently, there are no approved vaccines for human use. We have generated centrin knock out Leishmania (L.) mexicana (LmexCen-/-) mutants using CRISPR/Cas9. Centrin is a cytoskeletal protein required only for intracellular amastigote replication in Leishmania. Here, we investigated the safety, immunogenicity, and efficacy of LmexCen-/- parasites in vitro and in vivo. Our data shows that LmexCen-/- amastigotes present a growth defect, which results in significantly lower parasitic burdens and increased protective cytokine production in infected macrophages and dendritic cells,compared to LmexWT. Furthermore, LmexCen-/- parasites are safe in susceptible mouse models and efficacious against challenge with LmexWT in genetically different BALB/c and C57BL/6 mice. Vaccinated mice did not develop cutaneous lesions, displayed protective immunity, and showed significantly lower parasitic burdens compared to the controls. Overall, we demonstrate that LmexCen-/- parasites are a promising candidate vaccine against CL in pre-clinical models.Next, we explored the metabolic drivers of these vaccine-mediated immunological profiles. Metabolomics are emerging as a useful tool to uncover unknown networks that govern immune regulation and determine functional specialization. We analyzed the metabolic changes occurring after immunization with LmexCen-/- and compared them with LmexWT infection. Our results show enriched aspartate metabolism and pentose phosphate pathway (PPP) in ears immunized with LmexCen-/- parasites. These pathways are both known to promote M1 polarization in macrophages, and PPP in particular induces nitric oxide production in macrophages cultured with LmexCen-/-, suggesting a shift to a pro-inflammatory phenotype following immunization. Furthermore, immunized mice showed enriched taurine/hypotaurine metabolism in their ears, and linoleic acid in their lymph nodes, important to enhance macrophage and T cell responses against Leishmania. Uncovering the unique metabolic signatures of vaccination and disease is invaluable to identify novel markers of vaccine efficacy and understand the correlates of protective immunity.Metabolomics can also be used to investigate interesting physiological phenomena in CL and identify the molecular mechanisms responsible. In particular, CL is known to cause painless lesions, indicating that Leishmania infection modulates pain signals within the infected area. Through mass spectrometry analysis, we found elevated levels of caffeine metabolites in L. mexicana-infected compared to uninfected macrophages. Similar results were obtained at the lesion site during chronic infection. These caffeine metabolites are anti-inflammatory and display analgesic properties. Furthermore, we found enriched arachidonic acid (AA) metabolism during infection in vivo. AA is a metabolite of endocannabinoids, well established anti-inflammatory and analgesic mediators. We also observed significantly higher transcript levels of enzymes involved in endocannabinoid biosynthesis, and significantly lower expression of enzymes important for their degradation in infected mice. This study provides the first evidence of metabolic pathways with a potential molecular basis for the analgesia experienced by CL patients. Overall, furthering our understanding of leishmaniasis, as well as the metabolic and immunological changes that affect resistance and susceptibility, can have broadimplications for the development of novel preventive and therapeutic strategies to fill a worldwide critical need.
- Subjects :
- Microbiology
Immunology
Parasitology
Neurosciences
Cutaneous leishmaniasis
Leishmania mexicana
live-attenuated vaccine
CRISPR/Cas9
centrin
growth defect
immunogenicity
efficacy
metabolic reprogramming
pentose phosphate pathway
painless lesions
caffeine metabolism
arachidonic acid metabolism
endocannabinoids
Subjects
Details
- Language :
- English
- Database :
- OpenDissertations
- Publication Type :
- Dissertation/ Thesis
- Accession number :
- ddu.oai.etd.ohiolink.edu.osu1648831730997539