Higher levels of circulating TIMP-4 in preeclampsia is strongly associated with clinical parameters and microRNA

Circulating miRNAs and Preeclampsia: From Implantation to Epigenetics

In this review, we comprehensively present the literature on circulating microRNAs (miRNAs) associated with preeclampsia, a pregnancy-specific disease considered the primary reason for maternal and fetal mortality and morbidity. miRNAs are single-stranded non-coding RNAs, 20-24 nt long, which control mRNA expression. Changes in miRNA expression can induce a variation in the relative mRNA level and influence cellular homeostasis, and the strong presence of miRNAs in all body fluids has made them useful biomarkers of several diseases. Preeclampsia is a multifactorial disease, but the etiopathogenesis remains unclear. The functions of trophoblasts, including differentiation, proliferation, migration, invasion and apoptosis, are essential for a successful pregnancy. During the early stages of placental development, trophoblasts are strictly regulated by several molecular pathways; however, an imbalance in these molecular pathways can lead to severe placental lesions and pregnancy complications. We then discuss the role of miRNAs in trophoblast invasion and in the pathogenesis, diagnosis and prediction of preeclampsia. We also discuss the potential role of miRNAs from an epigenetic perspective with possible future therapeutic implications.

Circulating levels of tissue inhibitor of metalloproteinase 3, a protein with inhibitory effects on angiogenesis, are increased in pre-eclampsia

OBJECTIVE

To assess and compare circulating tissue inhibitor of metalloproteinase 3 (TIMP-3) concentrations between women with pre-eclampsia and healthy pregnant women. We also aimed to determine the relationships between circulating TIMP-3 and matrix metalloproteinase 2 (MMP-2), MMP-9, TIMP-1, and TIMP-2 concentrations in pre-eclampsia.

METHODS

A primary case-control study included patients with pre-eclampsia (n = 219) and gestational hypertension (n = 118), healthy pregnant women (n = 214), and non-pregnant women (n = 66), and a replication case-control study included patients with pre-eclampsia (n = 177) and healthy pregnant women (n = 124), all from southeastern Brazil. Plasma TIMP-3, MMP-2, MMP-9, TIMP-1, and TIMP-2 concentrations were assessed using commercially available enzyme-linked immunosorbent assay kits, and the relationships between them were analyzed using Spearman's correlation.

RESULTS

In our primary study, patients with pre-eclampsia and gestational hypertension exhibited increased TIMP-3 concentrations compared with healthy pregnant women (both P < 0.0001) and non-pregnant women (both P < 0.001). These findings were confirmed in the replication study, showing elevated TIMP-3 concentrations in women with pre-eclampsia versus healthy pregnant women (P < 0.001). We found no difference in TIMP-3 concentrations between early-onset and late-onset pre-eclampsia. Moreover, TIMP-3 concentrations were significantly correlated with plasma concentrations of TIMP-1 (r = 0.2333; P = 0.0086) and MMP-2 (r = 0.2159; P = 0.0156) in pre-eclampsia.

CONCLUSIONS

Circulating TIMP-3 concentration is increased in women with pre-eclampsia compared with healthy pregnant women, and it is positively correlated with plasma MMP-2 and TIMP-1 concentrations in pre-eclampsia.

Expression pattern and clinical significance of microRNA-let-7a and IFN-gamma in placental tissue of patients with preeclampsia with severe features

OBJECTIVES

Preeclampsia with severe features (PECsf) is a common disease in pregnant women. let-7a and IFN-gamma (interferon-gamma) are involved in diagnosis and prognosis of preeclampsia. This study explored effects of let-7a and IFN-gamma on PECsf patients.

METHODS

The placental tissue of 21 PECsf, 19 preeclampsia without severe features (PEC), and 20 normal pregnant women were collected, and clinical data were recorded. let-7a and IFN-gamma expressions in placental tissue were detected. The correlation between let-7a/IFN-gamma expression and clinical indexes was analyzed. According to let-7a and IFN-gamma expressions, PECsf patients were assigned into Hlet-7a group (let-7a high expression group), Llet-7a group (let-7a low expression group), HIFN-gamma group (IFN-gamma high expression group) and LIFN-gamma group (IFN-gamma low expression group). The incidence of adverse prognosis was compared.

RESULTS

let-7a and IFN-gamma were highly expressed in placental tissue of preeclampsia patients, with significant differences between PEC and PECsf. The high expressions of let-7a and IFN-gamma were positively correlated with mean arterial pressure, lactate dehydrogenase, and 24 h urinary protein in placental tissues of PECsf patients. High let-7a and IFN-gamma expressions were correlated with adverse outcomes of PECsf.

CONCLUSIONS

High let-7a and IFN-gamma expressions were correlated with clinical features, and could be used as biomarkers for treatment and poor prognosis of PECsf.

Comprehensive analyses of DNA methylation of the TIMP3 promoter in placentas from early-onset and late-onset preeclampsia

Preeclampsia (PE) is classified into late-onset (LOPE) or early-onset (EOPE) according to gestational age of onset (≥34 or <34 weeks, respectively), and into preterm and term (delivery at <37 or ≥37 weeks, respectively). An imbalanced expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) impairs proper placentation in PE, and DNA methylation (DNAm) may affect their expression. We performed comprehensive analyses of DNAm and TIMP3 expression in placentas from PE reclassified into EOPE, LOPE, and term PE. We identified significant differentially methylated probes at the TIMP3 promoter in PE (28), EOPE (38), LOPE (20), and term PE (4) compared to controls, and in EOPE vs. LOPE (8). Moreover, we found a hypomethylation >70% in all groups (except EOPE vs. LOPE) and an increased TIMP3 expression in corresponding placental samples from PE, EOPE and LOPE compared to controls (p<0.05). Our findings highlight the role of DNAm of the TIMP3 promoter region regarding an epigenetic mechanism in PE.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Upregulated long noncoding RNA Linc00261 in pre-eclampsia and its effect on trophoblast invasion and migration via regulating miR-558/TIMP4 signaling pathway

Pre-eclampsia (PE) is a leading cause of maternal and perinatal morbidity and mortality but the exact underlying mechanisms of PE pathogenesis remain elusive. Accumulated data suggested that the long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of PE. The present study identified the changes of lncRNA Linc00261 in PE and its effects on trophoblasts invasion and migration. Our results showed that the expression of Linc00261 was upregulated in placental tissues of PE women compared with those of healthy pregnant women. Overexpression of Linc00261 suppressed cell invasion and migration, induced cell apoptosis, and caused cell-cycle arrest at G0 /G1 phase of HTR-8/SVneo cells; while knockdown of Linc00261 had the opposite effects on the HTR-8/SVneo cells. Mechanistic studies showed Linc00261 functioned as a competing endogenous RNA for miR-558 in HTR-8/SVneo cells, and miR-558 was negatively regulated by Linc00261. The expression level of miR-558 in the PE group was significantly lower than the control group, and the expression level of Linc00261 was negatively correlated with the expression level of miR-558 in the placental tissues of women with PE. Furthermore, miR-558 was found to negatively regulate the expression of TIMP metallopeptidase inhibitor 4 (TIMP4) via targeting the 3' untranslated region in the HTR-8/SVneo cells. Overexpression of miR-558 increased HTR-8/SVneo cell invasion and migration, which was attenuated by TIMP4 overexpression. More importantly, both overexpression of miR-558 and knockdown of TIMP4 partially reversed the suppressive effects of Linc00261 overexpression on cell invasion and migration of HTR-8/SVneo cells. Collectively, our results for the first time showed the upregulation of Linc00261 in the placental tissues of severe PE patients. The mechanistic results indicated that Linc00261 exerted the suppressive effects on the trophoblast invasion and migration via targeting miR-558/TIMP4 axis, which may involve in the pathogenesis of PE.

Circulating Tissue Inhibitor of Metalloproteinase-4 levels are not a Predictor of Preeclampsia in the period between 20 and 25 Weeks of Gestation

OBJECTIVE

 To evaluate whether the circulating level of tissue inhibitor of metalloproteinase-4 (TIMP-4) in the period between 20 and 25 weeks of gestation is a predictor of preeclampsia.

METHODS

 We have performed a case-control study, nested in a prospective study cohort in Ribeirão Preto, in the state of São Paulo, Brazil. Of the 1,400 pregnant women evaluated between 20 and 25 weeks of gestation, 460 delivered in hospitals outside of our institution. Of the 940 pregnant women who completed the protocol, 30 developed preeclampsia. Healthy pregnant women (controls, n = 90) were randomly selected from the remaining 910 participants. From blood samples collected between 20 and 25 weeks of gestation, we performed a screening of 55 angiogenesis-related proteins in 4 cases and 4 controls. The protein TIMP-4 was the most differentially expressed between cases and controls. Therefore, we measured this protein in all cases (n = 30) and controls selected (n = 90).

RESULTS

 There were no differences in the plasma TIMP-4 levels of cases compared with controls (1,144 ± 263 versus 1,160 ± 362 pg/mL, respectively; p > 0.05).

CONCLUSION

 Plasma TIMP-4 levels were not altered at 20 to 25 weeks of gestation, before the manifestation of clinical symptoms; therefore, they are not good predictors of the development of preeclampsia.