RESUMEN
Chagas disease caused by Trypanosoma cruzi parasite is an endemic infection in America. It is well known that T. cruzi causes a strong immunosuppression during the acute phase of infection. However, it is not clear whether T. cruzi infection is related to metabolic alterations in CD4 T cells that prevent downstream effector function. Here, we evaluated the CD4 T cell metabolic and mitochondrial profiles from non-infected (NI), acute phase (AP) and chronic phase (CP) T. cruzi infected mice. CD4 T cells from all groups showed increased glucose uptake after stimulation. Moreover, the bioenergetic analysis revealed a rise in glycolysis and a higher oxidative metabolism in CD4 T cells from the AP. These cells showed increased proton leak and uncoupling protein 3 (UCP3) expression that correlated with mitochondrial ROS (mROS) accumulation, mitochondrial membrane potential (MMP) depolarization and expression of PD-1. In addition, CD4 T cells with mitochondrial alteration displayed an activated phenotype, and were less functional and more prone to apoptosis. In contrast, mitochondrial alterations were not observed during in vivo activation of CD4 T cells in a model of OVA-immunization. The Mn-superoxide dismutase (SOD2) expression, which is involved in mROS detoxification, was increased during the AP and CP of infection. Remarkably, the apoptosis observed in CD4 T cells with MMP depolarization was prevented by incubation with N-acetyl cysteine (NAC). Thus, our results showed that infection triggered an exacerbated metabolism together with mROS production in CD4 T cells from the AP of infection. However, antioxidant availability may not be sufficient to avoid mitochondrial alterations rendering these cells more susceptible to apoptosis. Our investigation is the first to demonstrate an association between a disturbed metabolism and an impaired CD4 T cell response during T. cruzi infection.
Asunto(s)
Enfermedad de Chagas , Trypanosoma cruzi , Animales , Apoptosis , Linfocitos T CD4-Positivos , Enfermedad de Chagas/genética , Ratones , Especies Reactivas de OxígenoRESUMEN
OBJECTIVES: 17ß-oestradiol interacts with growth factors to modulate lactotroph cell population. However, contribution of isoforms of the oestrogen receptor in these activities is not fully understood. In the present study, we have established participation of α and ß oestrogen receptors in effects of 17ß-oestradiol on lactotroph proliferation induced by insulin and shown involvement of the NO/sGC/cGMP pathway. MATERIALS AND METHODS: Cell cultures were prepared from anterior pituitaries of female rats to evaluate lactotroph cell proliferation using bromodeoxyuridine (BrdUrd) detection, protein expression by western blotting and cGMP by enzyme immunoassay. RESULTS: In serum-free conditions, 17ß-oestradiol and α and ß oestrogen receptor agonists (PPT and DPN) failed to increase numbers of lactotroph cells undergoing mitosis. Co-incubation of 17ß-oestradiol/insulin and PPT/insulin significantly decreased lactotroph mitogenic activity promoted by insulin alone. Both ICI 182780 and NOS inhibitors (L-NMMA and L-NAME) induced reversal of the anti-proliferative effect promoted by 17ß-oestradiol/insulin and PPT/insulin. Moreover, 17ß-oestradiol, PPT and insulin increased sGC α1 protein expression and inhibited ß1, whereas co-incubation of 17ß-oestradiol/insulin or PPT/insulin induced increases of the two isoforms α1 and ß1. 17ß-oestradiol and insulin reduced cGMP production, while 17ß-oestradiol/insulin co-incubation increased this cyclic nucleotide. CONCLUSIONS: Our results suggest that 17ß-oestradiol is capable of arresting lactotroph proliferation induced by insulin through ER α with participation of the signalling NO/sGC/cGMP pathway.