RESUMEN

Autophagy is a lysosomal degradation pathway that removes protein aggregates and damaged organelles maintaining cellular integrity. It seems to be essential for cell survival during stress, starvation, hypoxia, and consequently to the placenta implantation and development. Preeclampsia (PE) is a multisystemic disorder characterized by the onset of hypertension associated or not with proteinuria and other maternal complications. Considering that the placenta seems to play an important role in the pathogenesis of PE, the objective of the present study was to evaluate protein levels of light chain protein (LC3), beclin-1, and the mammalian target of rapamycin (mTOR) in the placenta of pregnant women with PE. Placental tissues collected from 20 women with PE and 20 normotensive (NT) pregnant women were evaluated for LC3, beclin-1, and mTOR expression by qPCR and immunohistochemistry. The mRNA for LC3 and beclin-1 were significantly lower, while mTOR gene expression was significantly higher in the placenta of pregnant women with PE than in the NT group. Placentas of PE women showed significantly decreased protein expression of LC3-II and beclin-1, whereas mTOR was significantly increased compared with the NT pregnant women. There was a negative correlation between protein expression of mTOR and LC3-II in the placental tissue of PE women. In conclusion, the results showed autophagy deficiency suggesting that failure in this degradation process may contribute to the pathogenesis of PE; however, new studies involving cross-talk between autophagy and inflammatory molecular mechanisms might help to better understand the autophagy process in this obstetric pathology.

Asunto(s)

Placenta , Preeclampsia , Femenino , Embarazo , Humanos , Mujeres Embarazadas , Preeclampsia/genética , Beclina-1/genética , Beclina-1/metabolismo , Regulación hacia Abajo , Serina-Treonina Quinasas TOR/metabolismo , Autofagia/fisiología

RESUMEN

Autophagy is a lysosomal degradation pathway that removes protein aggregates and damaged organelles maintaining cellular integrity. It seems to be essential for cell survival during stress, starvation, hypoxia, and consequently to the placenta implantation and development. Preeclampsia (PE) is a multisystemic disorder characterized by the onset of hypertension associated or not with proteinuria and other maternal complications. Considering that the placenta seems to play an important role in the pathogenesis of PE, the objective of the present study was to evaluate protein levels of light chain protein (LC3), beclin-1, and the mammalian target of rapamycin (mTOR) in the placenta of pregnant women with PE. Placental tissues collected from 20 women with PE and 20 normotensive (NT) pregnant women were evaluated for LC3, beclin-1, and mTOR expression by qPCR and immunohistochemistry. The mRNA for LC3 and beclin-1 were significantly lower, while mTOR gene expression was significantly higher in the placenta of pregnant women with PE than in the NT group. Placentas of PE women showed significantly decreased protein expression of LC3-II and beclin-1, whereas mTOR was significantly increased compared with the NT pregnant women. There was a negative correlation between protein expression of mTOR and LC3-II in the placental tissue of PE women. In conclusion, the results showed autophagy deficiency suggesting that failure in this degradation process may contribute to the pathogenesis of PE; however, new studies involving cross-talk between autophagy and inflammatory molecular mechanisms might help to better understand the autophagy process in this obstetric pathology.

RESUMEN

INTRODUCTION: Preeclampsia is a human pregnancy-specific syndrome characterized by the onset of hypertension and proteinuria. These manifestations may occur before the 34th week of gestation or from this period on, being denominated early-onset or late-onset preeclampsia respectively. The etiology of both disorders seems to differ qualitatively; therefore, different strategies of prevention and treatment must be studied. OBJECTIVES: The aim of the present study is to determine whether the plasma levels of heat-shock proteins Hsp60 and Hsp70 as well as specific antibodies anti-Hsp60 and anti-Hsp70 may differentiate early-onset from late-onset preeclampsia. METHODS: We evaluated 175 pregnant women with PE (55 early-onset PE and 120 late-onset PE). Plasma was obtained from peripheral blood and Hsp60, Hsp70 as well as anti-Hsp60 and anti-Hsp70 antibody levels were determined by enzyme immunoassay. Uric acid levels were also determined in the plasma of patients. For statistical analyses, the Mann-Whitney U-test and the Spearman rank order correlation were applied with significance level set at 5%. RESULTS: Hsp70 levels obtained from early-onset PE group were significantly higher than the late-onset PE women and showed positive correlation with uric acid (r=0.4547; p=0.0028). The Hsp60 production was similar in both groups. Our results also indicate that there was no significant difference of anti-Hsp60 and anti-Hsp70 antibody levels between women with early- and late-onset PE. However,these antibody levels were high,indicating a strong relationship with the production of HSP60 and Hsp70 protein. CONCLUSION: Association between levels of Hsp70 and uric acid in plasma of patients with early-onset PE seems to reflect the oxidative stress in this group of patients. This study provides evidence that Hsp70 determination may be utilized to assess the differentiation between early- and late-onset PE. FINANCIAL SUPPORT: FAPESP 2010/09241-2.

RESUMEN

INTRODUCTION: Toll-like receptor (TLR)-4 and TLR-2 are involved in inflammatory response of monocytes. These cells are activated in pregnant women with preeclampsia (PE), and over-produce inflammatory cytokines. TLR4 may recognize endogenous ligands, the so-called danger signals released by damaged cells, leading to production of pro-inflammatory cytokines. OBJECTIVES: This study investigated TLR2 and TLR4 expression and cytokine production by monocytes from women with PE before and after stimulation with TLR ligands. METHODS: Monocytes (5×10(5)cell/mL) were obtained from 32 preeclamptic (PE) and 20 normotensive (NT) pregnant women in the last trimester of pregnancy. TLR2 and TLR4 expression on monocyte surface was determined by flow cytometry in non-stimulated cells, and after 18h of culture with lipopysaccharide (LPS) and peptidoglycan (PG). TNF-α, IL-10 and IL-12p70 production by these cells stimulated or not with LPS or PG was evaluated by enzyme immunoassay. Results were analyzed by non-parametric tests with significance level set at 5%. RESULTS: In the absence of stimulation, the basal TLR4 expression by monocytes detected by the median fluorescence intensity (MFI) was significantly higher in the PE group than in the NT group while no significant differences were observed between groups in relation to endogenous TLR2 expression. An increase in TLR4 MFIs was detected after monocytes from NT pregnant women were stimulated with LPS while TLR2 expression was increased after PG-stimulation. No alterations in TLR expression was detected after LPS or PG-stimulation in monocytes from patients with PE. Evaluation of endogenous cytokine levels in supernatant culture of monocytes showed higher concentrations of TNF-α and IL-12p70 in preeclamptic women in comparison with the NT group, whereas IL-10 values were significantly higher in NT pregnant women than in the PE group. In contrast, when monocytes were stimulated with the TLRs ligands LPS and PG, the release of TNF-α was significantly reduced, while IL-12p70 levels were significantly higher in women with PE compared to NT group. IL-10 production was similar in both groups studied. CONCLUSION: The basal up-regulation of TLR4 expression associated with endogenous high TNF-α and IL-12p70 production by monocytes from preeclamptic women confirms the activated profile of these cells by the disease process. These findings provide new insights into possible roles for TLRs in the pathogenesis of systemic inflammation detected in PE. FINANCIAL SUPPORT: FAPESP 2009/11924-3 and 2010/20207-0.