GABAA receptor composition and function on CD4+ T cells during the development of EAE

FERNÁNDEZ HURST, NICOLÁS; ZANETTI S.; BOUZAT CECILIA B.; ROTH GERMAN A.

Mar del Plata

Congreso; LXII Reunión Anual de la Sociedad Argentina de Inmunología (SAI) y LIX Reunión Científica de la Sociedad Argentina de Investigación Clínica (SAIC); 2014

SAIC - SAI

Experimental autoimmune encephalomyelitis (EAE) is an animal model that mimics many of the clinical and pathological features of the human disease, Multiple sclerosis. CD4+ T cells exert a critical role during the induction and development of the disease. In previous studies it was shown that T cells express GABAA receptors and in parallel the treatment with Diazepam, an allosteric agonist of GABAA receptor, reduced the incidence and clinical signs of EAE. In order to explain the effect of Diazepam in vivo during EAE, we evaluated the presence, composition and functionality of GABAA receptors on CD4+ T cells isolated from popliteal lymph nodes of controls and EAE animals. Also the possible non-neuronal cell plasticity phenomenon was investigated in immune cells comparing with brain tissue. The animals were sensitized with myelin in complete Freund?s adjuvant (CFA) to induce EAE or CFA alone as control group, and sacrificed during the acute state of the disease (13-14 days post-induction). The mononuclear cells (MNC) were isolated from the draining popliteal lymph nodes and the in vitro proliferation induced by anti-CD3 and in presence of GABAA agonists (GABA, Muscimol, Diazepam) was evaluated. GABAA agonists reduced the proliferation of CD4+ T cells (p<0.05). CD4+ T cells were also sorted and lysed in trizol to evaluate the subunit composition of GABAA receptor and a fraction of frontal cortex tissue was obtained for comparison. We observed that CD4+ T cells obtained from EAE animals does not have mRNA for Gamma2 subunit in contrast with CFA animals (p< 0.05). We did not find the same difference in frontal cortex. These results indicate that during the development of EAE occurs a non-neuronal cell plasticity phenomenon. Also, these data suggest that GABAA agonists can modulate the proliferation of CD4+ T cell, and therefore the Diazepam effect in vivo appear not to be mediated by GABAA receptor on CD4+ T cells since Gamma2 subunit is required for benzodiazepine binding.