Extracellular vesicles spread adaptive pro-inflammmatory responses triggered by Triiodothyronine (T3) on mice dendritic cells (DCs)

NEGRETTI-BORGA D; ALAMINO VA; SOLER MF; BRAVO-MIANA R; BLANCO A; DONADIO, AC; MONTESINOS, MM; PELLIZAS CG

Congreso; Reunión de Sociedades de Biociencias 2020; 2020

Sociedad de Investigación Clínica (SAIC) y Sociedad Argentina de Inmunología (SAI)

T3 is the biologically more active thyroid hormone. DCs are specializedantigen presenting cells. T3 activates mice DCs (T3-DCs)inducing Th1 and Th17 proinflammatory, and cytotoxic responses,restraining Tregs. On this basis, antitumor antigen-specific T3-DCsbased vaccination strategies were exploited successfully for melanomaand colon cancer in mice. Extracellular vesicles (EVs) arenano-sized membrane vesicles that play key roles in intercellularcommunication. We reported that EVs released by T3-DCs (T3-EVs)activated syngeneic DCs with a pro-inflammatory profile, contributingto paracrine DC communication in vitro. To go further, the aim ofthis study was to evaluate the adaptive modulatory role of T3-EVs.Bone marrow DCs obtained from C57BL/6 WT mice were stimulated(or not) with T3 (10nM) for 18h. DC-EV fractions were isolated bydifferential ultracentrifugation of culture supernatants (2,000g: 2K;10,000g: 10K; and 100,000g: 100K). Allogenic splenocytes wereobtained from BALB/c mice and stimulated with DC-EV fractionsof T3-stimulated and Control (C) cells for 6 days. Intracellular andsecreted cytokine production were analyzed by flow cytometryand ELISA. Statistical analysis: Sidak?s multiple comparisons test.P<0.05 was considered statistically significant. Results showed that100 K and 2K T3-EVs increased CD8 splenocyte subpopulation (vstheir C). Moreover, the secretion of IFN-γ and IL-17 were augmentedin splenocyte cultures after 2K T3-EVs stimulus (vs C). Similarly,10K T3-EVs augmented IL17 secretion (vs C). We conclude that T3-EVs activated allogenic splenocytes increasing CD8 subpopulationin vitro, in an EV-fraction dependent manner. Besides, the secretionof splenocyte pro-inflammatory cytokines augmented after 2Kand 10K T3-EVs stimulus. This study underscores the role of EVsin immune-endocrine crosstalk and provides initial tools for futuredesigns of T3-DC based immunotherapies. Further research to enlightenthis topic is under course.