Lizhou Sun

Metabolic Syndrome Risk after Gestational Diabetes: A Systematic Review and Meta-Analysis

Background A number of studies have been conducted to investigate the risk of metabolic syndrome (MS) after gestational diabetes mellitus (GDM), but the results are contradictory. Accordingly, we performed a systematic review and meta-analysis to assess the association between these two conditions. The aim was to better understand the risks of MS with prior gestational diabetes. Methods Pubmed, ISI Web of Science, and Cochrane databases from September 1, 1979 to July 11, 2013 were searched to identify relevant studies. 17 studies containing 5832 women and 1149 MS events were included. We calculated the odds ratio (OR) with 95% confidence interval (CI) in analysis for each study using a random-effect or fixed-effect model. We also determined heterogeneity among these 17 articles and their publication bias. Results Women with a history of gestational diabetes had a significantly higher risk of MS than those who had a normal pregnancy (OR, 3.96; 95% CI, 2.99 to 5.26), but had significant heterogeneity (I 2 = 52.6%). The effect remained robust (OR, 4.54; 95% CI, 3.78–5.46) in the subgroup of Caucasians, but no association (OR, 1.28; 95% CI, 0.64–2.56) was found in Asians. Heterogeneity was reduced (body mass index (BMI) matched group I 2 = 14.2%, BMI higher in the GDM group I 2 = 13.2%) in the subgroup of BMI. In addition, mothers with higher BMI in the GDM group had higher risk of MS than those in the BMI matched group (BMI higher in GDM group OR, 5.39; 95% CI, 4.47–6.50, BMI matched group OR, 2.53; 95% CI, 1.88–3.41). Conclusions This meta-analysis demonstrated increased risk of MS after gestational diabetes. Therefore, attention should be given to preventing or delaying the onset of MS in GDM mothers, particularly in Caucasian and obese mothers.

Tools for Investigation of the RNA Endonuclease Activity of Mammalian Argonaute2 Protein

Mammalian Argonaute2 (Ago2) protein is the key player of RNA-induced silencing complexes (RISCs), regulating gene function through RNA interference. In this paper, a method to investigate the RNA endonuclease activity of Ago2 is reported using electrochemical technique with G-quadruplex-hemin complexes as signal transduction probes. Experimental results reveal that Ago2 may exhibit its slicer activity without any biological partners or ATP in wide pH and temperature ranges; thus, a method to assay the activity of the enzyme is proposed. For purified samples, the endonuclease activity of Ago2 can be quantified in the range from 6.25 to 25 nM with a detection limit of 5.02 nM. In the case of porcine cardiocyte lysates which contain a certain amount of Ago2, a linear correlation can be also obtained between the electrochemical signal and the dilution radio of the lysates. The proposed method shows desirable sensitivity, high selectivity, and excellent reproducibility, implying that this method may hold considerable potential for functional studies of Ago2 and clinical diagnosis in the future.

Upregulation of Long Noncoding RNA SPRY4-IT1 Modulates Proliferation, Migration, Apoptosis, and Network Formation in Trophoblast Cells HTR-8SV/neo

SPRY4-IT1 has been reported to have extremely high expression in normal placenta tissues. It is a Long noncoding RNA (lncRNA), which is associated with cell growth, migration, invasion, and apoptosis in melanoma. A 2.8-fold increase of SPRY4-IT1 expression was validated by Real-time reverse transcription-polymerase chain reaction (qRT-PCR) in severe preeclamptic placenta as compared with that of the normal ones (n=25) in this study. Furthermore, the role of SPRY4-IT1 in proliferation, migration, apoptosis, and network formation ability of trophoblast cells HTR-8/SVneo was assessed. Suppression of SPRY4-IT1 using siRNA treatment and its overexpression using plasmid targeting SPRY4-IT1 were performed in order to explore the biological function of SPRY4-IT1 in the development and progression of trophoblast cells HTR-8/SVneo, in vitro. The results showed that SPRY4-IT1 knockdown enhanced the cell migration and proliferation, and reduced the response of cells to apoptosis. However, exogenous SPRY4-IT1 overexpression significantly decreased the cell migration and proliferation, while increased cell apoptosis. Our study showed for the first time that aberrant expression of lncRNA SPRY4-IT1 might contribute to the abnormal condition of trophoblast cells HTR-8/SVneo. Therefore, we proposed SPRY4-IT1 as a novel lncRNA molecule, which might be associated with the pathogenesis of preeclampsia and might provide a new target for its early diagnosis and treatment.

Down‐Regulated Long Non‐Coding RNA MEG3 and its Effect on Promoting Apoptosis and Suppressing Migration of Trophoblast Cells

Preeclampsia is characterized by hypertension and proteinuria twenty weeks into pregnancy. Failure of uterine spiral artery remodeling contributes to preeclampsias development. The development might be associated with trophoblast cells functioning abnormally. Long non‐coding RNAs (lncRNAs) are aberrantly expressed in many diseases. Maternally expressed gene 3 (MEG3), one of these lncRNAs, might function as a tumor suppressor. Aberrant expression of MEG3 induces prenatal death, and little is known of MEG3s role in preeclampsia. This study aims to identify the role of lncRNA MEG3 on apoptosis and the migration of human trophoblast cells, and to investigate the involvement of lncRNA MEG3 in pathogenic mechanisms underlying preeclampsia. In this study, we found MEG3 levels were down‐regulated by approximately 80% in placental samples collected from preeclamptic patients (n = 30) compared to samples collected from normotensive patients (n = 30) by qRT‐PCR analysis. By designing RNA interference species to suppress MEG3 and specific plasmids designed to over‐express MEG3, we explored the role of MEG3 on the functions of two trophoblast cell‐lines, HTR‐8/SVneo and JEG3 cells. Over‐expression of MEG3 reduced apoptosis and promoted migration of HTR‐8/SVneo and JEG3 cells. Furthermore, inhibition of endogenous MEG3 increased apoptosis and decreased migration of HTR‐8/SVneo and JEG3 cells. Additionally, lncRNA MEG3 influenced expression of NF‐κB, Caspase‐3, and Bax protein expressions in trophoblast cells. Our findings highlight that abnormal levels of lncRNA MEG3 might lead to aberrant conditions in HTR‐8/SVneo and JEG3 trophoblast cells, which might be associated with uterine spiral artery remodeling failure and its contribution to preeclampsia. J. Cell. Biochem. 116: 542–550, 2015.

Activated effect of lignin on α-amylase.

This paper reports a new kind of activator of α-amylase, lignin, which can greatly increase α-amylase activity. The promoted ratio of lignin is even much higher than that of chloride ion, the traditional activator of α-amylase. Further experimental results reveal that lignin may interact with α-amylase to form a 1:1 complex with a binding constant of 4.47×10(5) M(-1). The binding is spontaneous and lignin/α-amylase complex formation is an exothermal reaction. Hydrogen bonding plays a key role and non-radiation energy transfers from α-amylase to lignin in the binding process. Lignin, combining with α-amylase, conforms to a first-order exponential decay function. The formation of the lignin/α-amylase complex results in the reduction of α-helical content from 57.7% to 53.9%, the increase of the polarity around tryptophan residues, the decrease of the hydrophobicity, and the enlargement of protein granule volume. This work will give a deeper insight into lignin as a kind of dietary fibre, known as an important food functional factor. Furthermore, it also contributes to the exploration of an activator of α-amylase, used in the food industry.

Resveratrol Inhibits Trophoblast Apoptosis through Oxidative Stress in Preeclampsia-Model Rats

Resveratrol has been shown to be a therapeutic agent for cardiovascular disorders by maintaining a lower redox level in vivo through its anti-oxidant properties. Resveratrol can prevent cells from p53- and reactive oxygen species-dependent apoptosis induced by interleukin-1b. We identified an inhibitory effect of resveratrol against oxidative stress and apoptosis using the TUNEL assay in NG-Nitro-l-arginine methyl ester-induced preeclampsia in rats. To investigate a possible association between resveratrol and the apoptosis caused by oxidative stress in vitro, assays for superoxide dismutase and malondialdehyde as well as flow cytometric analyses were conducted in HTR-8/SVneo cells after hypoxic treatment with or without resveratrol for 24 h. These data suggest that resveratrol significantly opposes the effects of oxidative stress in vivo and in vitro.

Interaction between curcumin and mimetic biomembrane

Curcumin, a major bioactive compound in turmeric, has a broad spectrum of antioxidant, anticarcinogenic, antimutagenic and anti-inflammatory properties. At the molecular level, curcumin modulates many structurally unrelated membrane proteins through several signaling pathways. Curcumin has been suggested to change the properties of cell membranes and affect the membrane-bound proteins indirectly; however, the detailed mechanism has yet to be investigated. In this paper, self-assembled bilayer lipid membranes are artificially constructed on the surface of a gold electrode to mimic biomembranes, and interaction between the supported membranes and curcumin is studied electrochemically. Results show that curcumin interacts with the membranes strongly, in a concentration-dependent manner. At low concentrations, curcumin tends to insert into the outer monolayer only, while at high concentrations, it may also begin to penetrate the inner monolayer. The results obtained in this work may enhance our understanding of the effect of curcumin, and possibly flavonoids, on cell membranes and membrane proteins.

The Lnc RNA SPRY4-IT1 Modulates Trophoblast Cell Invasion and Migration by Affecting the Epithelial-Mesenchymal Transition

Preeclampsia is a common, pregnancy-specific disease and a major contributor to maternal and foetal morbidity and mortality. Some placental abnormalities, including deficient implantation, abnormal trophoblast cell function, and improper placental vascular development, are believed to lead to preeclampsia. The long noncoding RNA SPRY4-IT1 is more highly expressed in preeclamptic human placentas than in normal placentas. We assessed the role of epithelial-mesenchymal transition (EMT)-associated invasion and migration in HTR-8/SVneo trophoblast cells. Overexpression of SPRY4-IT1 suppressed trophoblast cell migration and invasion, whereas reduced expression of SPRY4-IT1 prevented the EMT process. Mechanistically, an RNA immunoprecipitation experiment showed that SPRY4-IT1 bound directly to HuR and mediated the β-catenin expression associated with EMT in HTR-8/SVneo cells. Moreover, the expression levels of genes in the WNT family, such as WNT3 and WNT5B, were changed after transfection of HTR-8/SVneo with SPRY4-IT1. Together, our results highlight the roles of SPRY4-IT1 in causing trophoblast cell dysfunction by acting through the Wnt/β-catenin pathway, and consequently in impairing spiral artery remodelling. These results suggest a new potential therapeutic target for intervention against preeclampsia.

Simulation and assay of protein biotinylation with electrochemical technique.

Protein biotinylation plays an important role in metabolism and transcription regulation, so study of protein biotinylation has received more and more interests. In this work, the bifunctional Escherichia coli biotin-inducible repressor protein A (BirA) and its substrate for protein biotinylation, a unique peptide with a specific sequence, are introduced as a model to electrochemically simulate the committed step in fatty acid biosynthesis. With the help of gold nanoparticles and peroxidase-labeled streptavidin involved in the electrochemical system, protein biotinylation is achieved on the surface of the working electrode, and the process of protein biotinylation can be electrochemically assayed by the obtained electrochemical response. Therefore, a new method to assay protein biotinylation is proposed and this work may provide a new perspective for understanding protein biotinylation in vitro.

The lncRNA TUG1 modulates proliferation in trophoblast cells via epigenetic suppression of RND3

Due to limited treatment options, pre-eclampsia (PE) is associated with fetal perinatal and maternal morbidity and mortality. During the causes of PE, failure of uterine spiral artery remodeling which might be related to functioning abnormally of trophoblast cells, result in the occurrence and progression of PE. Recently, abnormal expression of long non-coding RNAs (lncRNAs), as imperative regulators involved in human diseases progression (included PE), which has been indicated by increasing evidence. In this research, we found that TUG1, a lncRNA, was markedly reduced in placental samples from patients with PE. Loss-function assays indicated that knockdown TUG1 significantly affected cell proliferation, apoptosis, migration and network formation in vitro. RNA-seq revealed that TUG1 could affect abundant genes, and then explore the function and regulatory mechanism of TUG1 in trophoblast cells. Furthermore, RNA immunoprecipitation and chromatin immunoprecipitation assays validated that TUG1 can epigenetically inhibit the level of RND3 through binding to EZH2, thus promoting PE development. Therefore, via illuminating the TUG1 mechanisms underlying PE development and progression, our findings might furnish a prospective therapeutic strategy for PE intervention.