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

NEGRETTI BORGA DANA; ALAMINO VA; SOLER MF; BRAVO MIANA RDC; BLANCO A; DONADIO AC; MONTESINOS MM; PELLIZAS CG

Buenos Aires

Congreso; Reunión Anual de Sociedades de Biociencias SAIC-SAI-SAFIS (Virtual); 2020

T3 is the biologically more active thyroid hormone. DCs are specialized antigen 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-DCs based vaccination strategies were exploited successfully for melanoma and colon cancer in mice. Extracellular vesicles (EVs) are nano-sized membrane vesicles that play key roles in intercellular communication. We reported that EVs released by T3-DCs (T3-EVs) activated syngeneic DCs with a pro-inflammatory profile, contributing to paracrine DC communication in vitro. To go further, the aim of this 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 by differential 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 and secreted cytokine production were analyzed by flow cytometry and ELISA. Statistical analysis: Sidak’s multiple comparisons test. P<0.05 was considered statistically significant. Results showed that 100 K and 2K T3-EVs increased CD8 splenocyte subpopulation (vs their C). Moreover, the secretion of IFN-γ and IL-17 were augmented in 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 subpopulation in vitro, in an EV-fraction dependent manner. Besides, the secre-tion of splenocyte pro-inflammatory cytokines augmented after 2K and 10K T3-EVs stimulus. This study underscores the role of EVs in immune-endocrine crosstalk and provides initial tools for future designs of T3-DC based immunotherapies. Further research to enlighten this topic is under course.