Association between cytokine profile and transcription factors produced by T cells subsets in early- and late- onset preeclampsia

Author(s)

Vanessa Rocha Ribeiro

• Document type: Master's Dissertation
• Press: Botucatu. 2017-03-13.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina. Botucatu
• Defense date: 2017-02-22
• Advisor: Maria Terezinha Serrão Peraçoli

Abstract

Introduction: Preeclampsia (PE) is an obstetric pathology and one of the main causes of maternal and fetal morbidity and mortality. In PE there is a state of maladaptation of immunological tolerance, characterized by abnormal activation of the innate and adaptive immune system. Regulatory T cells (Treg) represent a population of T lymphocytes responsible for tolerance maintenance and inflammation control, whereas Th17 cells mediate different types of inflammatory reactions. Therefore, the balance between Treg and Th17 cells may be critical for fetal tolerance and PE prevention. Objective: To evaluate the subpopulations of CD4+ T cells (Th1, Th2, Th17 and Treg) and the cytokine profile produced by these cells in pregnant women with PE, classified in early-onset PE and late-onset PE. Methods: Sixty pregnant women, 20 normotensive and 40 preeclamptic women, matched by gestational age, were studied. Pregnant women with PE were classified according to clinical manifestations in early-onset PE (<34 weeks gestation; n = 20) and late-onset PE (≥ 34 weeks gestation; n = 20). Peripheral blood mononuclear cells (PBMCs) obtained from pregnant women were evaluated for the production of pro and anti-inflammatory cytokines and expression of transcription factors involved in the characterization of CD4+ T cell subpopulations. Expression of the intracytoplasmic transcription factors of Th1 (T-bet), Th2 (GATA-3), Th17 (RORc) and Treg (FoxP3) cells was assessed by flow cytometry and the gene expression of these transcription factors was determined by reverse-transcription quantitative polymerase chain reaction (RT-qPCR) shortly after blood collection to evaluate the endogenous expression of these different T-cell subpopulations. The cytokine profile of Th1 cells (IFN-γ and TNF-α), Th2 (IL -4), Th17 (IL-6, IL-17 and IL-22) and Treg (IL-10 and TGF-β1) were measured in the plasma of the pregnant women by the ELISA. The results were analyzed using parametric or non-parametric tests with a significance level of 5%. Results: Th1 and Th17 inflammatory profiles were identified by a significant increase in mean fluorescence intensity (FMI) and by the percentage of cells expressing specific transcription factors in pregnant women with early-onset PE and late-onset PE in relation to the normotensive groups with corresponding gestational age. The percentage of Th17 cells was significantly higher in early-onset PE than in late-onset PE group. On the other hand, analysis of Th2 and Treg anti-inflammatory profiles showed percentages of cells expressing GATA-3 and FoxP3 significantly lower in the early- and late-onset PE groups compared to the normotensive groups, whereas the comparison between preeclamptic groups showed significantly lower percentage of Treg cells in pregnant women with early-onset PE. The gene expression of the T-bet transcription factor by PBMCs did not show significant differences between the preeclamptic and normotensive pregnant groups. Significant increase in the gene expression of RORc and decrease in the expression of the GATA-3 and FoxP3 genes were observed in both groups of preeclamptic women compared with the normotensive ones of corresponding gestational age. Among the preeclamptic pregnant women lower transcriptional level of GATA-3 transcription factor was detected in early-onset PE. Plasma levels of the cytokines IFN-γ, IL-6, IL-17 and TNF-α were significantly higher in pregnant women with PE, whereas IL-10 and TGF-β1 concentrations were significantly lower than in the normotensive corresponding groups. It was also observed higher levels of IL-6, IL-17, TGF-β1 and TNF-α in early-onset than in late-onset PE group. Protein expression of IL-4 (Th2 profile) and IL-22 (Th17 profile), did not show significant differences between the groups studied. Conclusion: The results show that the balance between Treg and Th17 cells is deficient in PE, with polarization to the Th17 profile in early-onset PE. This imbalance can be attributed to the predominance of pro-inflammatory cytokines over the anti-inflammatory ones present in the circulation of pregnant women with preeclampsia. (AU)

• FAPESP's process: 14/25124-7 - Association between cytokine profile and transcription factors produced by T cells subsets in early- and late- onset preeclampsia
• Grantee: Vanessa Rocha Ribeiro Vasques
• Support Opportunities: Scholarships in Brazil - Master