Dendritic cell metabolism is targeted by thyroid hormone action

BLANCO A; NEGRETTI BORGA, DM; PUENTES EN; TEIXEIRA MP; DONADIO AC; MONTESINOS MM; PELLIZAS CG

Curitiba

Congreso; XIX LATS Congress; 2023

Latin American Thyroid Society (LATS)

The adaptive immune response is initiated after antigens (Ag) recognition by professional Ag presenting cells, like Dendritic Cells (DC), which integrate these signals and activate T lymphocytes to different effector profiles. The differentiation of DC from murine bone marrow precursors (BMP) with granulocyte and macrophages colony stimulating factor (GM-DC) is one of the in vitro models most used to study DC’s biology. Our group demonstrated that Triiodothyronine (T3) induced GM-DC’s maturation and activation, directing pro-inflammatory and cytotoxic T cells responses, restraining regulatory signals. These results were successfully exploited in T3-stimulated GM-DC (T3-GM-DC)-based antitumor vaccines against melanoma and colon carcinoma in mice. In recent years, it became clear that DC’s function in response to stimulus is highly dependent on its cellular metabolism. Maturation signals induce a metabolic reprograming in GM-DC, favoring glycolytic metabolism over oxidative phosphorylation (OXPHOS). Sustained commitment to glycolysis relays on OXPHOS inhibition caused by nitric oxide (NO) produced by inducible NO Synthase (iNOS). On this basis, considering the potential of T3-GM-DC vaccines on cancer immunotherapy, and given the well-known role of T3 as a metabolic regulator, our aim was to assess T3 effects on GM-DC’s metabolic programming. GM-DC were differentiated from C57BL/6 mice BMP and stimulated (or not) with T3 (10nM, T3- GM-DC) for different time points. Glucose and lactate were measured in culture’s supernatants (SN) with commercial kits. Glucose uptake was evaluated using the glucose analog fluorescent dye 2-NBDG by Flow Cytometry. Glucose transporter 1 (Glut1) and iNOS expression were analyzed by Western Blot. Nitrite levels were measured in SN by the Griess reaction. Statistics: ANOVA, t test, t test with Welch’s correction or Mann Whitney test, p<0.05 was considered statistically significant. Results showed a significant increase in glucose consumption in a time dependent manner after T3 stimulus of GM-DC. This process was accompanied by a higher lactate production in T3-GM-DC (p<0.01), indicating an anaerobic use of the glucose. In addition, T3-GM-DC exhibited a significant increase in both glucose uptake and Glut1 expression (p<0.05) when compared to GM-DC. Besides, T3-GM-DC expressed high levels of iNOS (p<0.01), not detected in GM-DC. In accordance, nitrite levels, indicative of NO production, were significantly increased in T3-GM-DC (p<0.05) compared to GM-DC. This study gives the first insights into the impact of T3 on DC’s metabolism, focusing on the glycolytic pathway. In this regard, the increase in the glycolysis may be the consequence of OXPHOS’ inhibition caused by NO. Further research under course will help elucidating the DC’s metabolic reprogramming induced by T3 and its impact on DC’s functionality, giving the basis to develop new strategies to improve immunotherapies by manipulating the immunogenic potential of DC.