SHIGA TOXIN 2 (STX2) AND LPS FROM ENTERO- HEMORRHAGIC ESCHERICHIA COLI (EHEC) PRODUCE A TLR4-INDEPENDENT MICROGLIAL REACTIVITY AND PRO-INFLAMMATORY CYTOKINES

CELI AB.; VILLAREAL A.; ELIZAGARAY L.; GOLDSTEIN J.

CABA

Congreso; Reunión Anual de Sociedades de Biociencia; 2020

Sociedad Argentina de Investigación Clínica

Stx2 from EHEC is the main cause of hemolytic uremic syndromethat is defined clinically by microangiopathic hemolytic anemia,thrombocytopenia, and acute renal failure. Stx2 can also lead toencephalopathy with motor, cognitive and emotional impairmentsin 30% of cases. We have studied that Stx2 can bind to neuronsthrough its receptor Gb3. Other authors have reported that Stx2 maybind to TLR4 in leukocytes, which leads to its activation and cytokinerelease. Given that microglial cells (MC) are CNS resident macro-phages, we hypothesize that MC would respond to Stx2 through aTLR4 receptor. Therefore, our aim was to determine by in vivo andin vitro studies whether Stx2 produces MC activation through TLR4and cytokine release. Mice were subjected to the following sublethaltreatments: vehicle (control) or Stx2 (3ng)+LPS (800ng), to deter-mine MC reactivity by immunofluorescence and cytokine releaseby flow cytometry. In vitro assays of MC were obtained from TLR4KO rat brains which were treated with either control, LPS (50ng/ml), Stx2 (50 or 200ng/ml) or Stx2+LPS. One way ANOVA analysis,and Bonferroni post-hoc analysis were performed for in vivo and invitro studies. After 24h of treatment, Stx2+LPS treated mice showedan increase in the expression of IBA1 as well as in the number ofMC (p