Immunomodulatory role of Sphingosine kinase 1 (SK1) on Triiodothyronine (T3)-matured dendritic cells (DC) and the driven adaptive response

NEGRETTI-BORGA D; BLANCO A; PIRES TEXEIRA M; SOLER MF; PUENTES E; DONADIO AC; CLARKKE CJ; MONTESINOS MM; HANNUN YA; PELLIZAS CG

Mar del Plata

Congreso; LXVII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC). LXX Reunión Anual de la Sociedad Argentina de Inmunología (SAI).; 2022

Sociedad Argentina de Investigación Clínica y Sociedad Argentina de Inmunología

Our group demonstrated that T3 generates adaptive proinflammatory and cytotoxic responses through DC activation, restraining regulatory signals. This protocol was successfully exploited in T3-stimulated DC (T3-DC)-based antitumor vaccines. T3 effects are mainlytriggered by non-genomic mechanisms involving thyroid hormonereceptor, Akt and NF-kB. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid produced by SK1 and 2. Although this pathwayis involved in many proinflammatory conditions, little is known aboutits role in innate immune cells. We aim to evaluate the role of SK1in T3-DC, and the driven adaptive immunity. Bone marrow DC wereobtained from C57BL/6 WT or SK1-KO mice and stimulated (or not)with T3 (10nM). PF-543 (SK1 inhibitor, 100nM) was added, and 30min later the T3 stimuli (PF-T3-DC). After 30 min, p-Akt/total Aktwas analyzed by Western Blot. Allogenic splenocytes isolated fromBALB/c mice were co-cultured with T3-DC or PF-T3-DC (exposedto T3 for 18h), for 3 days. Viability and proliferation were evaluatedby FACS. Cytokines were measured by FACS and ELISA. Statistical analysis: Two-way ANOVA/Tukey test, and paired t test. p<0.05,statistically significant. Results showed that intracellular IL-12 production was increased in T3-DC (18h T3 exposure) from SK1-KOmice (vs WT, p< 0.0001). Accordingly, IL-12 secretion was higherin PF-T3-DC (vs T3-DC, p< 0.005). Of note, DC viability was notmodified by PF-543. In turn, SK1 inhibition reduced p-Akt in T3-DC(p< 0.005). IFN-γ and IL-17 production and secretion, as well assplenocytes proliferation, were modified in the co-culture with PFT3-DC (vs. T3-DC, p<0.05). Our results revealed for the first timethat the Sphingolipid intracellular pathway is involved in T3-DC activation. The immunomodulation exerted by SK1 on T3-DC and thedriven adaptive response disclose a novel role of Sphingolipids inthe immune-endocrine crosstalk. Further research would unveil theintimate signaling process.