Lipidomic Analysis of Extracellular Vesicles Reveals Hybrid Vesicle Signatures during Giardia intestinalis Host Interaction

Julia Eduarda Charleaux1, Karoline dos Anjos Lima2, Bruna Sabatke1, Georgia Atella2, Marcel Ivan Ramirez 1

1. ICC, Instituto Carlos Chagas ; Rua Prof. Algacyr Munhoz Mader 3775, Curitiba, PR, 81350-010 (41) 3316-3230
2. UFRJ, Universidade Federal do Rio de Janeiro; Av Pedro Calmon 550, Rio de Janeiro

Introduction
Giardia intestinalis is a protozoan parasite responsible for giardiasis, an intestinal infection characterised by diarrhoea and epithelial barrier disruption. Extracellular vesicles (EVs) released by both the parasite and host cells have emerged as critical mediators of intercellular communication during infection. This study aimed to characterise the lipidomic composition of EVs derived from the parasite (gEVs), host epithelial cells (hEVs), and hybrid vesicles formed during host-parasite interaction (intEVs), to understand their functional relevance in modulating host responses.

Materials and Methods
EVs were isolated by differential ultracentrifugation and size-exclusion chromatography from cultures of G. intestinalis, Caco-2 cells, and co-cultures. EVs were classified as large (LEVs) or small (SEVs) and analysed at 1 h and 24 h of interaction. Lipidomic characterisation involved high-performance thin-layer chromatography (HPTLC) and radiolabelled palmitate incorporation assays to assess lipid content and turnover.

Results
IntEVs displayed a distinct lipid profile compared to gEVs and hEVs, with a marked enrichment in sphingolipids, cholesterol, phosphatidylserine, and ceramides. LEVs were rich in phosphatidylcholine and sphingomyelin, while SEVs showed higher levels of lysophospholipids and signalling lipids. Radiolabelled palmitate incorporation was significantly greater in intEVs, indicating active lipid remodelling. These lipidomic features are consistent with increased fusogenic capacity and potential for modulating immune signalling and vesicle uptake.

Conclusions
The hybrid vesicles (intEVs) formed during Giardia-host interaction exhibit a unique and dynamic lipid composition, distinct from those of parasite- or host-derived vesicles alone. Their enriched content in bioactive lipids suggests an enhanced ability to alter host cell functions and promote parasite survival. These findings provide new insights into vesicle-mediated pathogenesis and point to lipid components as promising therapeutic targets in giardiasis.

 

Agradecimentos: