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2023 FDA Science Forum

Leishmania mexicana Centrin Knock out Parasites Promote M1-polarizing Metabolic Changes

Download the Poster (PDF; 2.21 MB)
Authors:
Poster Author(s)
Volpedo, Greta, Ohio State University; Pacheco-Fernandez, Thalia, Ohio State University; Oljuskin, Timur, USDA; Azodi, Nazli, FDA/CBER/OBRR; Markle, Hannah, FDA/CBER/OBRR; Hamano, Shinjiro, Nagasaki University; Matlashewski, Greg, McGill University; Satoskar, Abhay R., Ohio State University; Gannavaram, Sreenivas, FDA/CBER/OBRR; Nakhasi, Hira, FDA/CBER/OBRR
Center:
Contributing Office
Center for Biologics Evaluation and Research

Abstract

Poster Abstract

Background:

Leishmaniasis is a protozoan disease with a prevalence of 12 million individuals in more than 90 countries, with no vaccine currently approved for use. Our group has developed genetically modified centrin-deficient Leishmania parasites (LmexCen-/-) that show excellent safety and efficacy in pre-clinical studies against virulent L. mexicana parasites. LmexCen-/- parasites have been shown to induce a Th1 response through greater production of IL-12.

Purpose:

Understanding early immunoregulatory mechanisms following vaccination with LmexCen-/- parasites is important to evaluate safety and efficacy characteristics. Metabolomic reprogramming of host cells has been shown to drive early changes in the immune response against Leishmania parasites. Therefore, we sought to explore the metabolomic immune regulation underlying protection following LmexCen-/- immunization.

Methodology:

C57/BL6 mice were infected with wild type L. mexicana (LmexWT)and LmexCen-/-. The infected ear tissues were collected 7 days post infection and analyzed by untargeted LC/MS mass spectrometry, and the data were analyzed with the Metaboanalyst 5.0 for pathway analysis and Metscape 3.1.1 for integrative network analysis. To verify results, murine bone marrow-derived macrophages (BMDMs) were infected with LmexWT and LmexCen-/. BMDMs were cultured with inhibitors of the pentose phosphate pathway (PPP), and the expression levels of genes of interest were measured via qRT-PCR.

Results:

Our results showed that the PPP was enriched in the ears of LmexCen-/--immunized mice, compared to naïve and LmexWT-infected mice. Mass spectrometry analysis revealed upregulated PPP in the LmexCen-/- group, which is known to polarize macrophages towards a proinflammatory M1 phenotype. Treatment with PPP inhibitors resulted in a significant reduction in nitric oxide (NO) levels, IL-12 levels in both the uninfected and LmexCen-/- groups compared to their controls. Similar reduction in IL-1β was also observed in the LmexCen-/- group compared to controls.

Conclusion:

Application of metabolomic analysis to vaccine studies identified immune mechanisms of protection and may help identify novel biomarkers of vaccine efficacy of a live-attenuated vaccine candidate for human leishmaniasis.

Poster Image
2023 Science Forum Poster Thumbnail – Leishmania mexicana Centrin Knock out Parasites Promote M1-polarizing Metabolic Changes

Download the Poster (PDF; 2.21 MB)

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