Triiodothyronine-stimulated Dendritic cells (DCs) release extracellular vesicles able to activate syngeneic immature DCs

BRAVO MIANA, ROCÍO M.; DONADIO, ANA CAROLINA; NEGRETTI BORGA, DANA MARÍA; DE PAUL, ANA L; PELLIZAS, CLAUDIA G; SOLER, MARÍA FLORENCIA; MONTESINOS, MARÍA DEL MAR

Buenos Aires

Congreso; XVII Latin American Thyroid Congress; 2019

Latin American Thyroid Society

Introduction: Triiodothyronine (T3) triggers Th1 and Th17 profiles through dendritic cell (DC) activation driving pro-inflammatoryand cytotoxic responses and restraining tolerogenic signals. Objectives: To characterize Extracellular Vesicles secreted by DCs (EV-DC)from control and T3-stimulated conditions and to assess their role in paracrine DC communication. Methods: Immature bone marrowDCs (iDC) obtained from C57BL/6 mice were stimulated (or not, control) with T3 (5 nM-18h). Secreted EV-DC from controland T3-stimulated DCs (EV-DC-T3) were isolated by differential ultracentrifugation (2,000g: 2K; 10,000g: 10K and 100,000g:100K). Morphological analysis was conducted by Transmission Electron Microscopy (TEM) and dynamic light scattering (DLS), andmolecular analysis by western blot (CD9 and CD81). A functional assay evaluated the syngeneic DC profile induced by EV-DC fromboth conditions (CD11c, MHCII and CD86 by FACS; IL-12 by FACS and ELISA). Statistical analysis: Dunn?s Multiple Comparisonsand Mann Whitney tests. Results: TEM and DLS analysis of EV-DC did not show morphological changes in control vs EV-DC-T3and revealed higher frequency of EV-DC > 150 nm for 2K and 10K-EVs, whereas 100K exhibited more than 90% of EV-DC sized30-150 nm. All fractions exhibited CD9 and CD81. 10K and 100K from both control and EV-DC-T3 activated syngeneic DCs(IL-12 production). The same effect was induced by 2K EV-DC-T3, but not by control EV-DC. Conclusion: The study allowed thecharacterization of EV-DC and demonstrated their ability to induce syngeneic iDC activation with fraction and condition dependence.Results suggest that EV-DC may be involved in the adaptive response induced by T3 exposure to DCs. Further ongoing studies willenlighten this issue. Conflict of interest: None declared.